14 files changed, 6518 insertions, 0 deletions
diff --git a/phpBB/phpbb/db/driver/driver.php b/phpBB/phpbb/db/driver/driver.php
new file mode 100644
index 0000000000..01dd66cd6e
--- /dev/null
+++ b/phpBB/phpbb/db/driver/driver.php
@@ -0,0 +1,1078 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* Database Abstraction Layer
+*/
+abstract class driver implements driver_interface
+{
+	var $db_connect_id;
+	var $query_result;
+	var $return_on_error = false;
+	var $transaction = false;
+	var $sql_time = 0;
+	var $num_queries = array();
+	var $open_queries = array();
+
+	var $curtime = 0;
+	var $query_hold = '';
+	var $html_hold = '';
+	var $sql_report = '';
+
+	var $persistency = false;
+	var $user = '';
+	var $server = '';
+	var $dbname = '';
+
+	// Set to true if error triggered
+	var $sql_error_triggered = false;
+
+	// Holding the last sql query on sql error
+	var $sql_error_sql = '';
+	// Holding the error information - only populated if sql_error_triggered is set
+	var $sql_error_returned = array();
+
+	// Holding transaction count
+	var $transactions = 0;
+
+	// Supports multi inserts?
+	var $multi_insert = false;
+
+	/**
+	* Current sql layer
+	*/
+	var $sql_layer = '';
+
+	/**
+	* Wildcards for matching any (%) or exactly one (_) character within LIKE expressions
+	*/
+	var $any_char;
+	var $one_char;
+
+	/**
+	* Exact version of the DBAL, directly queried
+	*/
+	var $sql_server_version = false;
+
+	/**
+	* Constructor
+	*/
+	function __construct()
+	{
+		$this->num_queries = array(
+			'cached'	=> 0,
+			'normal'	=> 0,
+			'total'		=> 0,
+		);
+
+		// Fill default sql layer based on the class being called.
+		// This can be changed by the specified layer itself later if needed.
+		$this->sql_layer = substr(get_class($this), strlen('phpbb\db\driver\\'));
+
+		// Do not change this please! This variable is used to easy the use of it - and is hardcoded.
+		$this->any_char = chr(0) . '%';
+		$this->one_char = chr(0) . '_';
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_layer()
+	{
+		return $this->sql_layer;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_db_name()
+	{
+		return $this->dbname;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_any_char()
+	{
+		return $this->any_char;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_one_char()
+	{
+		return $this->one_char;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_db_connect_id()
+	{
+		return $this->db_connect_id;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_error_triggered()
+	{
+		return $this->sql_error_triggered;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_error_sql()
+	{
+		return $this->sql_error_sql;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_transaction()
+	{
+		return $this->transaction;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_time()
+	{
+		return $this->sql_time;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_error_returned()
+	{
+		return $this->sql_error_returned;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_multi_insert()
+	{
+		return $this->multi_insert;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function set_multi_insert($multi_insert)
+	{
+		$this->multi_insert = $multi_insert;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_return_on_error($fail = false)
+	{
+		$this->sql_error_triggered = false;
+		$this->sql_error_sql = '';
+
+		$this->return_on_error = $fail;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_num_queries($cached = false)
+	{
+		return ($cached) ? $this->num_queries['cached'] : $this->num_queries['normal'];
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_add_num_queries($cached = false)
+	{
+		$this->num_queries['cached'] += ($cached !== false) ? 1 : 0;
+		$this->num_queries['normal'] += ($cached !== false) ? 0 : 1;
+		$this->num_queries['total'] += 1;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_close()
+	{
+		if (!$this->db_connect_id)
+		{
+			return false;
+		}
+
+		if ($this->transaction)
+		{
+			do
+			{
+				$this->sql_transaction('commit');
+			}
+			while ($this->transaction);
+		}
+
+		foreach ($this->open_queries as $query_id)
+		{
+			$this->sql_freeresult($query_id);
+		}
+
+		// Connection closed correctly. Set db_connect_id to false to prevent errors
+		if ($result = $this->_sql_close())
+		{
+			$this->db_connect_id = false;
+		}
+
+		return $result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		if (empty($query))
+		{
+			return false;
+		}
+
+		// Never use a negative total or offset
+		$total = ($total < 0) ? 0 : $total;
+		$offset = ($offset < 0) ? 0 : $offset;
+
+		return $this->_sql_query_limit($query, $total, $offset, $cache_ttl);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrowset($query_id = false)
+	{
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($query_id !== false)
+		{
+			$result = array();
+			while ($row = $this->sql_fetchrow($query_id))
+			{
+				$result[] = $row;
+			}
+
+			return $result;
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		$this->sql_freeresult($query_id);
+		$query_id = $this->sql_query($this->last_query_text);
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		// We do not fetch the row for rownum == 0 because then the next resultset would be the second row
+		for ($i = 0; $i < $rownum; $i++)
+		{
+			if (!$this->sql_fetchrow($query_id))
+			{
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchfield($field, $rownum = false, $query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($query_id !== false)
+		{
+			if ($rownum !== false)
+			{
+				$this->sql_rowseek($rownum, $query_id);
+			}
+
+			if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+			{
+				return $cache->sql_fetchfield($query_id, $field);
+			}
+
+			$row = $this->sql_fetchrow($query_id);
+			return (isset($row[$field])) ? $row[$field] : false;
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_like_expression($expression)
+	{
+		$expression = utf8_str_replace(array('_', '%'), array("\_", "\%"), $expression);
+		$expression = utf8_str_replace(array(chr(0) . "\_", chr(0) . "\%"), array('_', '%'), $expression);
+
+		return $this->_sql_like_expression('LIKE \'' . $this->sql_escape($expression) . '\'');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_not_like_expression($expression)
+	{
+		$expression = utf8_str_replace(array('_', '%'), array("\_", "\%"), $expression);
+		$expression = utf8_str_replace(array(chr(0) . "\_", chr(0) . "\%"), array('_', '%'), $expression);
+
+		return $this->_sql_not_like_expression('NOT LIKE \'' . $this->sql_escape($expression) . '\'');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_case($condition, $action_true, $action_false = false)
+	{
+		$sql_case = 'CASE WHEN ' . $condition;
+		$sql_case .= ' THEN ' . $action_true;
+		$sql_case .= ($action_false !== false) ? ' ELSE ' . $action_false : '';
+		$sql_case .= ' END';
+		return $sql_case;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' || ' . $expr2;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_buffer_nested_transactions()
+	{
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				// If we are within a transaction we will not open another one, but enclose the current one to not loose data (preventing auto commit)
+				if ($this->transaction)
+				{
+					$this->transactions++;
+					return true;
+				}
+
+				$result = $this->_sql_transaction('begin');
+
+				if (!$result)
+				{
+					$this->sql_error();
+				}
+
+				$this->transaction = true;
+			break;
+
+			case 'commit':
+				// If there was a previously opened transaction we do not commit yet...
+				// but count back the number of inner transactions
+				if ($this->transaction && $this->transactions)
+				{
+					$this->transactions--;
+					return true;
+				}
+
+				// Check if there is a transaction (no transaction can happen if
+				// there was an error, with a combined rollback and error returning enabled)
+				// This implies we have transaction always set for autocommit db's
+				if (!$this->transaction)
+				{
+					return false;
+				}
+
+				$result = $this->_sql_transaction('commit');
+
+				if (!$result)
+				{
+					$this->sql_error();
+				}
+
+				$this->transaction = false;
+				$this->transactions = 0;
+			break;
+
+			case 'rollback':
+				$result = $this->_sql_transaction('rollback');
+				$this->transaction = false;
+				$this->transactions = 0;
+			break;
+
+			default:
+				$result = $this->_sql_transaction($status);
+			break;
+		}
+
+		return $result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_build_array($query, $assoc_ary = false)
+	{
+		if (!is_array($assoc_ary))
+		{
+			return false;
+		}
+
+		$fields = $values = array();
+
+		if ($query == 'INSERT' || $query == 'INSERT_SELECT')
+		{
+			foreach ($assoc_ary as $key => $var)
+			{
+				$fields[] = $key;
+
+				if (is_array($var) && is_string($var[0]))
+				{
+					// This is used for INSERT_SELECT(s)
+					$values[] = $var[0];
+				}
+				else
+				{
+					$values[] = $this->_sql_validate_value($var);
+				}
+			}
+
+			$query = ($query == 'INSERT') ? ' (' . implode(', ', $fields) . ') VALUES (' . implode(', ', $values) . ')' : ' (' . implode(', ', $fields) . ') SELECT ' . implode(', ', $values) . ' ';
+		}
+		else if ($query == 'MULTI_INSERT')
+		{
+			trigger_error('The MULTI_INSERT query value is no longer supported. Please use sql_multi_insert() instead.', E_USER_ERROR);
+		}
+		else if ($query == 'UPDATE' || $query == 'SELECT' || $query == 'DELETE')
+		{
+			$values = array();
+			foreach ($assoc_ary as $key => $var)
+			{
+				$values[] = "$key = " . $this->_sql_validate_value($var);
+			}
+			$query = implode(($query == 'UPDATE') ? ', ' : ' AND ', $values);
+		}
+
+		return $query;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_in_set($field, $array, $negate = false, $allow_empty_set = false)
+	{
+		if (!sizeof($array))
+		{
+			if (!$allow_empty_set)
+			{
+				// Print the backtrace to help identifying the location of the problematic code
+				$this->sql_error('No values specified for SQL IN comparison');
+			}
+			else
+			{
+				// NOT IN () actually means everything so use a tautology
+				if ($negate)
+				{
+					return '1=1';
+				}
+				// IN () actually means nothing so use a contradiction
+				else
+				{
+					return '1=0';
+				}
+			}
+		}
+
+		if (!is_array($array))
+		{
+			$array = array($array);
+		}
+
+		if (sizeof($array) == 1)
+		{
+			@reset($array);
+			$var = current($array);
+
+			return $field . ($negate ? ' <> ' : ' = ') . $this->_sql_validate_value($var);
+		}
+		else
+		{
+			return $field . ($negate ? ' NOT IN ' : ' IN ') . '(' . implode(', ', array_map(array($this, '_sql_validate_value'), $array)) . ')';
+		}
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_bit_and($column_name, $bit, $compare = '')
+	{
+		if (method_exists($this, '_sql_bit_and'))
+		{
+			return $this->_sql_bit_and($column_name, $bit, $compare);
+		}
+
+		return $column_name . ' & ' . (1 << $bit) . (($compare) ? ' ' . $compare : '');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_bit_or($column_name, $bit, $compare = '')
+	{
+		if (method_exists($this, '_sql_bit_or'))
+		{
+			return $this->_sql_bit_or($column_name, $bit, $compare);
+		}
+
+		return $column_name . ' | ' . (1 << $bit) . (($compare) ? ' ' . $compare : '');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function cast_expr_to_bigint($expression)
+	{
+		return $expression;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function cast_expr_to_string($expression)
+	{
+		return $expression;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER($column_name)";
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_multi_insert($table, $sql_ary)
+	{
+		if (!sizeof($sql_ary))
+		{
+			return false;
+		}
+
+		if ($this->multi_insert)
+		{
+			$ary = array();
+			foreach ($sql_ary as $id => $_sql_ary)
+			{
+				// If by accident the sql array is only one-dimensional we build a normal insert statement
+				if (!is_array($_sql_ary))
+				{
+					return $this->sql_query('INSERT INTO ' . $table . ' ' . $this->sql_build_array('INSERT', $sql_ary));
+				}
+
+				$values = array();
+				foreach ($_sql_ary as $key => $var)
+				{
+					$values[] = $this->_sql_validate_value($var);
+				}
+				$ary[] = '(' . implode(', ', $values) . ')';
+			}
+
+			return $this->sql_query('INSERT INTO ' . $table . ' ' . ' (' . implode(', ', array_keys($sql_ary[0])) . ') VALUES ' . implode(', ', $ary));
+		}
+		else
+		{
+			foreach ($sql_ary as $ary)
+			{
+				if (!is_array($ary))
+				{
+					return false;
+				}
+
+				$result = $this->sql_query('INSERT INTO ' . $table . ' ' . $this->sql_build_array('INSERT', $ary));
+
+				if (!$result)
+				{
+					return false;
+				}
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	* Function for validating values
+	* @access private
+	*/
+	function _sql_validate_value($var)
+	{
+		if (is_null($var))
+		{
+			return 'NULL';
+		}
+		else if (is_string($var))
+		{
+			return "'" . $this->sql_escape($var) . "'";
+		}
+		else
+		{
+			return (is_bool($var)) ? intval($var) : $var;
+		}
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_build_query($query, $array)
+	{
+		$sql = '';
+		switch ($query)
+		{
+			case 'SELECT':
+			case 'SELECT_DISTINCT';
+
+				$sql = str_replace('_', ' ', $query) . ' ' . $array['SELECT'] . ' FROM ';
+
+				// Build table array. We also build an alias array for later checks.
+				$table_array = $aliases = array();
+				$used_multi_alias = false;
+
+				foreach ($array['FROM'] as $table_name => $alias)
+				{
+					if (is_array($alias))
+					{
+						$used_multi_alias = true;
+
+						foreach ($alias as $multi_alias)
+						{
+							$table_array[] = $table_name . ' ' . $multi_alias;
+							$aliases[] = $multi_alias;
+						}
+					}
+					else
+					{
+						$table_array[] = $table_name . ' ' . $alias;
+						$aliases[] = $alias;
+					}
+				}
+
+				// We run the following code to determine if we need to re-order the table array. ;)
+				// The reason for this is that for multi-aliased tables (two equal tables) in the FROM statement the last table need to match the first comparison.
+				// DBMS who rely on this: Oracle, PostgreSQL and MSSQL. For all other DBMS it makes absolutely no difference in which order the table is.
+				if (!empty($array['LEFT_JOIN']) && sizeof($array['FROM']) > 1 && $used_multi_alias !== false)
+				{
+					// Take first LEFT JOIN
+					$join = current($array['LEFT_JOIN']);
+
+					// Determine the table used there (even if there are more than one used, we only want to have one
+					preg_match('/(' . implode('|', $aliases) . ')\.[^\s]+/U', str_replace(array('(', ')', 'AND', 'OR', ' '), '', $join['ON']), $matches);
+
+					// If there is a first join match, we need to make sure the table order is correct
+					if (!empty($matches[1]))
+					{
+						$first_join_match = trim($matches[1]);
+						$table_array = $last = array();
+
+						foreach ($array['FROM'] as $table_name => $alias)
+						{
+							if (is_array($alias))
+							{
+								foreach ($alias as $multi_alias)
+								{
+									($multi_alias === $first_join_match) ? $last[] = $table_name . ' ' . $multi_alias : $table_array[] = $table_name . ' ' . $multi_alias;
+								}
+							}
+							else
+							{
+								($alias === $first_join_match) ? $last[] = $table_name . ' ' . $alias : $table_array[] = $table_name . ' ' . $alias;
+							}
+						}
+
+						$table_array = array_merge($table_array, $last);
+					}
+				}
+
+				$sql .= $this->_sql_custom_build('FROM', implode(' CROSS JOIN ', $table_array));
+
+				if (!empty($array['LEFT_JOIN']))
+				{
+					foreach ($array['LEFT_JOIN'] as $join)
+					{
+						$sql .= ' LEFT JOIN ' . key($join['FROM']) . ' ' . current($join['FROM']) . ' ON (' . $join['ON'] . ')';
+					}
+				}
+
+				if (!empty($array['WHERE']))
+				{
+					$sql .= ' WHERE ' . $this->_sql_custom_build('WHERE', $array['WHERE']);
+				}
+
+				if (!empty($array['GROUP_BY']))
+				{
+					$sql .= ' GROUP BY ' . $array['GROUP_BY'];
+				}
+
+				if (!empty($array['ORDER_BY']))
+				{
+					$sql .= ' ORDER BY ' . $array['ORDER_BY'];
+				}
+
+			break;
+		}
+
+		return $sql;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_error($sql = '')
+	{
+		global $auth, $user, $config;
+
+		// Set var to retrieve errored status
+		$this->sql_error_triggered = true;
+		$this->sql_error_sql = $sql;
+
+		$this->sql_error_returned = $this->_sql_error();
+
+		if (!$this->return_on_error)
+		{
+			$message = 'SQL ERROR [ ' . $this->sql_layer . ' ]<br /><br />' . $this->sql_error_returned['message'] . ' [' . $this->sql_error_returned['code'] . ']';
+
+			// Show complete SQL error and path to administrators only
+			// Additionally show complete error on installation or if extended debug mode is enabled
+			// The DEBUG constant is for development only!
+			if ((isset($auth) && $auth->acl_get('a_')) || defined('IN_INSTALL') || defined('DEBUG'))
+			{
+				$message .= ($sql) ? '<br /><br />SQL<br /><br />' . htmlspecialchars($sql) : '';
+			}
+			else
+			{
+				// If error occurs in initiating the session we need to use a pre-defined language string
+				// This could happen if the connection could not be established for example (then we are not able to grab the default language)
+				if (!isset($user->lang['SQL_ERROR_OCCURRED']))
+				{
+					$message .= '<br /><br />An sql error occurred while fetching this page. Please contact an administrator if this problem persists.';
+				}
+				else
+				{
+					if (!empty($config['board_contact']))
+					{
+						$message .= '<br /><br />' . sprintf($user->lang['SQL_ERROR_OCCURRED'], '<a href="mailto:' . htmlspecialchars($config['board_contact']) . '">', '</a>');
+					}
+					else
+					{
+						$message .= '<br /><br />' . sprintf($user->lang['SQL_ERROR_OCCURRED'], '', '');
+					}
+				}
+			}
+
+			if ($this->transaction)
+			{
+				$this->sql_transaction('rollback');
+			}
+
+			if (strlen($message) > 1024)
+			{
+				// We need to define $msg_long_text here to circumvent text stripping.
+				global $msg_long_text;
+				$msg_long_text = $message;
+
+				trigger_error(false, E_USER_ERROR);
+			}
+
+			trigger_error($message, E_USER_ERROR);
+		}
+
+		if ($this->transaction)
+		{
+			$this->sql_transaction('rollback');
+		}
+
+		return $this->sql_error_returned;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_report($mode, $query = '')
+	{
+		global $cache, $starttime, $phpbb_root_path, $phpbb_path_helper, $user;
+		global $request;
+
+		if (is_object($request) && !$request->variable('explain', false))
+		{
+			return false;
+		}
+
+		if (!$query && $this->query_hold != '')
+		{
+			$query = $this->query_hold;
+		}
+
+		switch ($mode)
+		{
+			case 'display':
+				if (!empty($cache))
+				{
+					$cache->unload();
+				}
+				$this->sql_close();
+
+				$mtime = explode(' ', microtime());
+				$totaltime = $mtime[0] + $mtime[1] - $starttime;
+
+				echo '<!DOCTYPE html>
+					<html dir="ltr">
+					<head>
+						<meta charset="utf-8">
+						<meta http-equiv="X-UA-Compatible" content="IE=edge">
+						<title>SQL Report</title>
+						<link href="' . htmlspecialchars($phpbb_path_helper->update_web_root_path($phpbb_root_path) . $phpbb_path_helper->get_adm_relative_path()) . 'style/admin.css" rel="stylesheet" type="text/css" media="screen" />
+					</head>
+					<body id="errorpage">
+					<div id="wrap">
+						<div id="page-header">
+							<a href="' . build_url('explain') . '">Return to previous page</a>
+						</div>
+						<div id="page-body">
+							<div id="acp">
+							<div class="panel">
+								<span class="corners-top"><span></span></span>
+								<div id="content">
+									<h1>SQL Report</h1>
+									<br />
+									<p><b>Page generated in ' . round($totaltime, 4) . " seconds with {$this->num_queries['normal']} queries" . (($this->num_queries['cached']) ? " + {$this->num_queries['cached']} " . (($this->num_queries['cached'] == 1) ? 'query' : 'queries') . ' returning data from cache' : '') . '</b></p>
+
+									<p>Time spent on ' . $this->sql_layer . ' queries: <b>' . round($this->sql_time, 5) . 's</b> | Time spent on PHP: <b>' . round($totaltime - $this->sql_time, 5) . 's</b></p>
+
+									<br /><br />
+									' . $this->sql_report . '
+								</div>
+								<span class="corners-bottom"><span></span></span>
+							</div>
+							</div>
+						</div>
+						<div id="page-footer">
+							Powered by <a href="https://www.phpbb.com/">phpBB</a>&reg; Forum Software &copy; phpBB Limited
+						</div>
+					</div>
+					</body>
+					</html>';
+
+				exit_handler();
+
+			break;
+
+			case 'stop':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$this->sql_report .= '
+
+					<table cellspacing="1">
+					<thead>
+					<tr>
+						<th>Query #' . $this->num_queries['total'] . '</th>
+					</tr>
+					</thead>
+					<tbody>
+					<tr>
+						<td class="row3"><textarea style="font-family:\'Courier New\',monospace;width:99%" rows="5" cols="10">' . preg_replace('/\t(AND|OR)(\W)/', "\$1\$2", htmlspecialchars(preg_replace('/[\s]*[\n\r\t]+[\n\r\s\t]*/', "\n", $query))) . '</textarea></td>
+					</tr>
+					</tbody>
+					</table>
+
+					' . $this->html_hold . '
+
+					<p style="text-align: center;">
+				';
+
+				if ($this->query_result)
+				{
+					if (preg_match('/^(UPDATE|DELETE|REPLACE)/', $query))
+					{
+						$this->sql_report .= 'Affected rows: <b>' . $this->sql_affectedrows() . '</b> | ';
+					}
+					$this->sql_report .= 'Before: ' . sprintf('%.5f', $this->curtime - $starttime) . 's | After: ' . sprintf('%.5f', $endtime - $starttime) . 's | Elapsed: <b>' . sprintf('%.5f', $endtime - $this->curtime) . 's</b>';
+				}
+				else
+				{
+					$error = $this->sql_error();
+					$this->sql_report .= '<b style="color: red">FAILED</b> - ' . $this->sql_layer . ' Error ' . $error['code'] . ': ' . htmlspecialchars($error['message']);
+				}
+
+				$this->sql_report .= '</p><br /><br />';
+
+				$this->sql_time += $endtime - $this->curtime;
+			break;
+
+			case 'start':
+				$this->query_hold = $query;
+				$this->html_hold = '';
+
+				$this->_sql_report($mode, $query);
+
+				$this->curtime = explode(' ', microtime());
+				$this->curtime = $this->curtime[0] + $this->curtime[1];
+
+			break;
+
+			case 'add_select_row':
+
+				$html_table = func_get_arg(2);
+				$row = func_get_arg(3);
+
+				if (!$html_table && sizeof($row))
+				{
+					$html_table = true;
+					$this->html_hold .= '<table cellspacing="1"><tr>';
+
+					foreach (array_keys($row) as $val)
+					{
+						$this->html_hold .= '<th>' . (($val) ? ucwords(str_replace('_', ' ', $val)) : '&nbsp;') . '</th>';
+					}
+					$this->html_hold .= '</tr>';
+				}
+				$this->html_hold .= '<tr>';
+
+				$class = 'row1';
+				foreach (array_values($row) as $val)
+				{
+					$class = ($class == 'row1') ? 'row2' : 'row1';
+					$this->html_hold .= '<td class="' . $class . '">' . (($val) ? $val : '&nbsp;') . '</td>';
+				}
+				$this->html_hold .= '</tr>';
+
+				return $html_table;
+
+			break;
+
+			case 'fromcache':
+
+				$this->_sql_report($mode, $query);
+
+			break;
+
+			case 'record_fromcache':
+
+				$endtime = func_get_arg(2);
+				$splittime = func_get_arg(3);
+
+				$time_cache = $endtime - $this->curtime;
+				$time_db = $splittime - $endtime;
+				$color = ($time_db > $time_cache) ? 'green' : 'red';
+
+				$this->sql_report .= '<table cellspacing="1"><thead><tr><th>Query results obtained from the cache</th></tr></thead><tbody><tr>';
+				$this->sql_report .= '<td class="row3"><textarea style="font-family:\'Courier New\',monospace;width:99%" rows="5" cols="10">' . preg_replace('/\t(AND|OR)(\W)/', "\$1\$2", htmlspecialchars(preg_replace('/[\s]*[\n\r\t]+[\n\r\s\t]*/', "\n", $query))) . '</textarea></td></tr></tbody></table>';
+				$this->sql_report .= '<p style="text-align: center;">';
+				$this->sql_report .= 'Before: ' . sprintf('%.5f', $this->curtime - $starttime) . 's | After: ' . sprintf('%.5f', $endtime - $starttime) . 's | Elapsed [cache]: <b style="color: ' . $color . '">' . sprintf('%.5f', ($time_cache)) . 's</b> | Elapsed [db]: <b>' . sprintf('%.5f', $time_db) . 's</b></p><br /><br />';
+
+				// Pad the start time to not interfere with page timing
+				$starttime += $time_db;
+
+			break;
+
+			default:
+
+				$this->_sql_report($mode, $query);
+
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function get_estimated_row_count($table_name)
+	{
+		return $this->get_row_count($table_name);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function get_row_count($table_name)
+	{
+		$sql = 'SELECT COUNT(*) AS rows_total
+			FROM ' . $this->sql_escape($table_name);
+		$result = $this->sql_query($sql);
+		$rows_total = $this->sql_fetchfield('rows_total');
+		$this->sql_freeresult($result);
+
+		return $rows_total;
+	}
+}
diff --git a/phpBB/phpbb/db/driver/driver_interface.php b/phpBB/phpbb/db/driver/driver_interface.php
new file mode 100644
index 0000000000..8b487c5d42
--- /dev/null
+++ b/phpBB/phpbb/db/driver/driver_interface.php
@@ -0,0 +1,453 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+interface driver_interface
+{
+	/**
+	* Gets the name of the sql layer.
+	*
+	* @return string
+	*/
+	public function get_sql_layer();
+
+	/**
+	* Gets the name of the database.
+	*
+	* @return string
+	*/
+	public function get_db_name();
+
+	/**
+	* Wildcards for matching any (%) character within LIKE expressions
+	*
+	* @return string
+	*/
+	public function get_any_char();
+
+	/**
+	* Wildcards for matching exactly one (_) character within LIKE expressions
+	*
+	* @return string
+	*/
+	public function get_one_char();
+
+	/**
+	* Gets the time spent into the queries
+	*
+	* @return int
+	*/
+	public function get_sql_time();
+
+	/**
+	* Gets the connect ID.
+	*
+	* @return mixed
+	*/
+	public function get_db_connect_id();
+
+	/**
+	* Indicates if an error was triggered.
+	*
+	* @return bool
+	*/
+	public function get_sql_error_triggered();
+
+	/**
+	* Gets the last faulty query
+	*
+	* @return string
+	*/
+	public function get_sql_error_sql();
+
+	/**
+	* Indicates if we are in a transaction.
+	*
+	* @return bool
+	*/
+	public function get_transaction();
+
+	/**
+	* Gets the returned error.
+	*
+	* @return array
+	*/
+	public function get_sql_error_returned();
+
+	/**
+	* Indicates if multiple insertion can be used
+	*
+	* @return bool
+	*/
+	public function get_multi_insert();
+
+	/**
+	* Set if multiple insertion can be used
+	*
+	* @param bool $multi_insert
+	*/
+	public function set_multi_insert($multi_insert);
+
+	/**
+	* Gets the exact number of rows in a specified table.
+	*
+	* @param string $table_name Table name
+	* @return string	Exact number of rows in $table_name.
+	*/
+	public function get_row_count($table_name);
+
+	/**
+	* Gets the estimated number of rows in a specified table.
+	*
+	* @param string $table_name Table name
+	* @return string	Number of rows in $table_name.
+	*					Prefixed with ~ if estimated (otherwise exact).
+	*/
+	public function get_estimated_row_count($table_name);
+
+	/**
+	* Run LOWER() on DB column of type text (i.e. neither varchar nor char).
+	*
+	* @param string $column_name	The column name to use
+	* @return string		A SQL statement like "LOWER($column_name)"
+	*/
+	public function sql_lower_text($column_name);
+
+	/**
+	* Display sql error page
+	*
+	* @param string		$sql	The SQL query causing the error
+	* @return mixed		Returns the full error message, if $this->return_on_error
+	*					is set, null otherwise
+	*/
+	public function sql_error($sql = '');
+
+	/**
+	* Returns whether results of a query need to be buffered to run a
+	* transaction while iterating over them.
+	*
+	* @return bool	Whether buffering is required.
+	*/
+	public function sql_buffer_nested_transactions();
+
+	/**
+	* Run binary OR operator on DB column.
+	*
+	* @param string	$column_name	The column name to use
+	* @param int	$bit			The value to use for the OR operator,
+	*					will be converted to (1 << $bit). Is used by options,
+	*					using the number schema... 0, 1, 2...29
+	* @param string	$compare	Any custom SQL code after the check (e.g. "= 0")
+	* @return string	A SQL statement like "$column | (1 << $bit) {$compare}"
+	*/
+	public function sql_bit_or($column_name, $bit, $compare = '');
+
+	/**
+	* Version information about used database
+	*
+	* @param bool $raw			Only return the fetched sql_server_version
+	* @param bool $use_cache	Is it safe to retrieve the value from the cache
+	* @return string sql server version
+	*/
+	public function sql_server_info($raw = false, $use_cache = true);
+
+	/**
+	* Return on error or display error message
+	*
+	* @param bool	$fail		Should we return on errors, or stop
+	* @return null
+	*/
+	public function sql_return_on_error($fail = false);
+
+	/**
+	* Build sql statement from an array
+	*
+	* @param	string	$query		Should be on of the following strings:
+	*						INSERT, INSERT_SELECT, UPDATE, SELECT, DELETE
+	* @param	array	$assoc_ary	Array with "column => value" pairs
+	* @return	string		A SQL statement like "c1 = 'a' AND c2 = 'b'"
+	*/
+	public function sql_build_array($query, $assoc_ary = array());
+
+	/**
+	* Fetch all rows
+	*
+	* @param	mixed	$query_id	Already executed query to get the rows from,
+	*								if false, the last query will be used.
+	* @return	mixed		Nested array if the query had rows, false otherwise
+	*/
+	public function sql_fetchrowset($query_id = false);
+
+	/**
+	* SQL Transaction
+	*
+	* @param	string	$status		Should be one of the following strings:
+	*								begin, commit, rollback
+	* @return	mixed	Buffered, seekable result handle, false on error
+	*/
+	public function sql_transaction($status = 'begin');
+
+	/**
+	* Build a concatenated expression
+	*
+	* @param	string	$expr1		Base SQL expression where we append the second one
+	* @param	string	$expr2		SQL expression that is appended to the first expression
+	* @return	string		Concatenated string
+	*/
+	public function sql_concatenate($expr1, $expr2);
+
+	/**
+	* Build a case expression
+	*
+	* Note: The two statements action_true and action_false must have the same
+	* data type (int, vchar, ...) in the database!
+	*
+	* @param	string	$condition		The condition which must be true,
+	*							to use action_true rather then action_else
+	* @param	string	$action_true	SQL expression that is used, if the condition is true
+	* @param	mixed	$action_false	SQL expression that is used, if the condition is false
+	* @return	string		CASE expression including the condition and statements
+	*/
+	public function sql_case($condition, $action_true, $action_false = false);
+
+	/**
+	* Build sql statement from array for select and select distinct statements
+	*
+	* Possible query values: SELECT, SELECT_DISTINCT
+	*
+	* @param	string	$query	Should be one of: SELECT, SELECT_DISTINCT
+	* @param	array	$array	Array with the query data:
+	*					SELECT		A comma imploded list of columns to select
+	*					FROM		Array with "table => alias" pairs,
+	*								(alias can also be an array)
+	*		Optional:	LEFT_JOIN	Array of join entries:
+	*						FROM		Table that should be joined
+	*						ON			Condition for the join
+	*		Optional:	WHERE		Where SQL statement
+	*		Optional:	GROUP_BY	Group by SQL statement
+	*		Optional:	ORDER_BY	Order by SQL statement
+	* @return	string		A SQL statement ready for execution
+	*/
+	public function sql_build_query($query, $array);
+
+	/**
+	* Fetch field
+	* if rownum is false, the current row is used, else it is pointing to the row (zero-based)
+	*
+	* @param	string	$field		Name of the column
+	* @param	mixed	$rownum		Row number, if false the current row will be used
+	*								and the row curser will point to the next row
+	*								Note: $rownum is 0 based
+	* @param	mixed	$query_id	Already executed query to get the rows from,
+	*								if false, the last query will be used.
+	* @return	mixed		String value of the field in the selected row,
+	*						false, if the row does not exist
+	*/
+	public function sql_fetchfield($field, $rownum = false, $query_id = false);
+
+	/**
+	* Fetch current row
+	*
+	* @param	mixed	$query_id	Already executed query to get the rows from,
+	*								if false, the last query will be used.
+	* @return	mixed		Array with the current row,
+	*						false, if the row does not exist
+	*/
+	public function sql_fetchrow($query_id = false);
+
+	/**
+	* Returns SQL string to cast a string expression to an int.
+	*
+	* @param  string $expression An expression evaluating to string
+	* @return string             Expression returning an int
+	*/
+	public function cast_expr_to_bigint($expression);
+
+	/**
+	* Get last inserted id after insert statement
+	*
+	* @return	string		Autoincrement value of the last inserted row
+	*/
+	public function sql_nextid();
+
+	/**
+	* Add to query count
+	*
+	* @param bool $cached	Is this query cached?
+	* @return null
+	*/
+	public function sql_add_num_queries($cached = false);
+
+	/**
+	* Build LIMIT query
+	*
+	* @param	string	$query		The SQL query to execute
+	* @param	int		$total		The number of rows to select
+	* @param	int		$offset
+	* @param	int		$cache_ttl	Either 0 to avoid caching or
+	*				the time in seconds which the result shall be kept in cache
+	* @return	mixed	Buffered, seekable result handle, false on error
+	*/
+	public function sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0);
+
+	/**
+	* Base query method
+	*
+	* @param	string	$query		The SQL query to execute
+	* @param	int		$cache_ttl	Either 0 to avoid caching or
+	*				the time in seconds which the result shall be kept in cache
+	* @return	mixed	Buffered, seekable result handle, false on error
+	*/
+	public function sql_query($query = '', $cache_ttl = 0);
+
+	/**
+	* Returns SQL string to cast an integer expression to a string.
+	*
+	* @param	string	$expression		An expression evaluating to int
+	* @return string		Expression returning a string
+	*/
+	public function cast_expr_to_string($expression);
+
+	/**
+	 * Connect to server
+	 *
+	 * @param	string	$sqlserver		Address of the database server
+	 * @param	string	$sqluser		User name of the SQL user
+	 * @param	string	$sqlpassword	Password of the SQL user
+	 * @param	string	$database		Name of the database
+	 * @param	mixed	$port			Port of the database server
+	 * @param	bool	$persistency
+	 * @param	bool	$new_link		Should a new connection be established
+	 * @return	mixed	Connection ID on success, string error message otherwise
+	 */
+	public function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false);
+
+	/**
+	* Run binary AND operator on DB column.
+	* Results in sql statement: "{$column_name} & (1 << {$bit}) {$compare}"
+	*
+	* @param string	$column_name	The column name to use
+	* @param int	$bit			The value to use for the AND operator,
+	*								will be converted to (1 << $bit). Is used by
+	*								options, using the number schema: 0, 1, 2...29
+	* @param string	$compare		Any custom SQL code after the check (for example "= 0")
+	* @return string	A SQL statement like: "{$column} & (1 << {$bit}) {$compare}"
+	*/
+	public function sql_bit_and($column_name, $bit, $compare = '');
+
+	/**
+	* Free sql result
+	*
+	* @param	mixed	$query_id	Already executed query result,
+	*								if false, the last query will be used.
+	* @return	null
+	*/
+	public function sql_freeresult($query_id = false);
+
+	/**
+	* Return number of sql queries and cached sql queries used
+	*
+	* @param	bool	$cached		Should we return the number of cached or normal queries?
+	* @return	int		Number of queries that have been executed
+	*/
+	public function sql_num_queries($cached = false);
+
+	/**
+	* Run more than one insert statement.
+	*
+	* @param string	$table		Table name to run the statements on
+	* @param array	$sql_ary	Multi-dimensional array holding the statement data
+	* @return bool		false if no statements were executed.
+	*/
+	public function sql_multi_insert($table, $sql_ary);
+
+	/**
+	* Return number of affected rows
+	*
+	* @return	mixed		Number of the affected rows by the last query
+	*						false if no query has been run before
+	*/
+	public function sql_affectedrows();
+
+	/**
+	* DBAL garbage collection, close SQL connection
+	*
+	* @return	mixed		False if no connection was opened before,
+	*						Server response otherwise
+	*/
+	public function sql_close();
+
+	/**
+	* Seek to given row number
+	*
+	* @param	mixed	$rownum		Row number the curser should point to
+	*								Note: $rownum is 0 based
+	* @param	mixed	$query_id	ID of the query to set the row cursor on
+	*								if false, the last query will be used.
+	*								$query_id will then be set correctly
+	* @return	bool		False if something went wrong
+	*/
+	public function sql_rowseek($rownum, &$query_id);
+
+	/**
+	* Escape string used in sql query
+	*
+	* @param	string	$msg	String to be escaped
+	* @return	string		Escaped version of $msg
+	*/
+	public function sql_escape($msg);
+
+	/**
+	* Correctly adjust LIKE expression for special characters
+	* Some DBMS are handling them in a different way
+	*
+	* @param	string	$expression	The expression to use. Every wildcard is
+	*						escaped, except $this->any_char and $this->one_char
+	* @return string	A SQL statement like: "LIKE 'bertie_%'"
+	*/
+	public function sql_like_expression($expression);
+
+	/**
+	* Correctly adjust NOT LIKE expression for special characters
+	* Some DBMS are handling them in a different way
+	*
+	* @param	string	$expression	The expression to use. Every wildcard is
+	*						escaped, except $this->any_char and $this->one_char
+	* @return string	A SQL statement like: "NOT LIKE 'bertie_%'"
+	*/
+	public function sql_not_like_expression($expression);
+
+	/**
+	* Explain queries
+	*
+	* @param	string	$mode		Available modes: display, start, stop,
+	 *								add_select_row, fromcache, record_fromcache
+	* @param	string	$query		The Query that should be explained
+	* @return	mixed		Either a full HTML page, boolean or null
+	*/
+	public function sql_report($mode, $query = '');
+
+	/**
+	* Build IN or NOT IN sql comparison string, uses <> or = on single element
+	* arrays to improve comparison speed
+	*
+	* @param	string	$field			Name of the sql column that shall be compared
+	* @param	array	$array			Array of values that are (not) allowed
+	* @param	bool	$negate			true for NOT IN (), false for IN ()
+	* @param	bool	$allow_empty_set	If true, allow $array to be empty,
+	*								this function will return 1=1 or 1=0 then.
+	* @return string	A SQL statement like: "IN (1, 2, 3, 4)" or "= 1"
+	*/
+	public function sql_in_set($field, $array, $negate = false, $allow_empty_set = false);
+}
diff --git a/phpBB/phpbb/db/driver/factory.php b/phpBB/phpbb/db/driver/factory.php
new file mode 100644
index 0000000000..fb3a826254
--- /dev/null
+++ b/phpBB/phpbb/db/driver/factory.php
@@ -0,0 +1,443 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+use \Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+* Database Abstraction Layer
+*/
+class factory implements driver_interface
+{
+	/**
+	* @var driver_interface
+	*/
+	protected $driver = null;
+
+	/**
+	* @var ContainerInterface
+	*/
+	protected $container;
+
+	/**
+	* Constructor.
+	*
+	* @param ContainerInterface $container A ContainerInterface instance
+	*/
+	public function __construct(ContainerInterface $container)
+	{
+		$this->container = $container;
+	}
+
+	/**
+	* Return the current driver (and retrieved it from the container if necessary)
+	*
+	* @return driver_interface
+	*/
+	protected function get_driver()
+	{
+		if ($this->driver === null)
+		{
+			$this->driver = $this->container->get('dbal.conn.driver');
+		}
+
+		return $this->driver;
+	}
+
+	/**
+	* Set the current driver
+	*
+	* @param driver_interface $driver
+	*/
+	public function set_driver(driver_interface $driver)
+	{
+		$this->driver = $driver;
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_layer()
+	{
+		return $this->get_driver()->get_sql_layer();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_db_name()
+	{
+		return $this->get_driver()->get_db_name();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_any_char()
+	{
+		return $this->get_driver()->get_any_char();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_one_char()
+	{
+		return $this->get_driver()->get_one_char();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_db_connect_id()
+	{
+		return $this->get_driver()->get_db_connect_id();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_error_triggered()
+	{
+		return $this->get_driver()->get_sql_error_triggered();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_error_sql()
+	{
+		return $this->get_driver()->get_sql_error_sql();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_transaction()
+	{
+		return $this->get_driver()->get_transaction();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_time()
+	{
+		return $this->get_driver()->get_sql_time();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_sql_error_returned()
+	{
+		return $this->get_driver()->get_sql_error_returned();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_multi_insert()
+	{
+		return $this->get_driver()->get_multi_insert();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function set_multi_insert($multi_insert)
+	{
+		$this->get_driver()->set_multi_insert($multi_insert);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_row_count($table_name)
+	{
+		return $this->get_driver()->get_row_count($table_name);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function get_estimated_row_count($table_name)
+	{
+		return $this->get_driver()->get_estimated_row_count($table_name);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_lower_text($column_name)
+	{
+		return $this->get_driver()->sql_lower_text($column_name);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_error($sql = '')
+	{
+		return $this->get_driver()->sql_error($sql);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_buffer_nested_transactions()
+	{
+		return $this->get_driver()->sql_buffer_nested_transactions();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_bit_or($column_name, $bit, $compare = '')
+	{
+		return $this->get_driver()->sql_bit_or($column_name, $bit, $compare);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_server_info($raw = false, $use_cache = true)
+	{
+		return $this->get_driver()->sql_server_info($raw, $use_cache);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_return_on_error($fail = false)
+	{
+		return $this->get_driver()->sql_return_on_error($fail);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_build_array($query, $assoc_ary = array())
+	{
+		return $this->get_driver()->sql_build_array($query, $assoc_ary);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_fetchrowset($query_id = false)
+	{
+		return $this->get_driver()->sql_fetchrowset($query_id);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_transaction($status = 'begin')
+	{
+		return $this->get_driver()->sql_transaction($status);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $this->get_driver()->sql_concatenate($expr1, $expr2);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_case($condition, $action_true, $action_false = false)
+	{
+		return $this->get_driver()->sql_case($condition, $action_true, $action_false);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_build_query($query, $array)
+	{
+		return $this->get_driver()->sql_build_query($query, $array);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_fetchfield($field, $rownum = false, $query_id = false)
+	{
+		return $this->get_driver()->sql_fetchfield($field, $rownum, $query_id);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_fetchrow($query_id = false)
+	{
+		return $this->get_driver()->sql_fetchrow($query_id);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function cast_expr_to_bigint($expression)
+	{
+		return $this->get_driver()->cast_expr_to_bigint($expression);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_nextid()
+	{
+		return $this->get_driver()->sql_nextid();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_add_num_queries($cached = false)
+	{
+		return $this->get_driver()->sql_add_num_queries($cached);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		return $this->get_driver()->sql_query_limit($query, $total, $offset, $cache_ttl);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_query($query = '', $cache_ttl = 0)
+	{
+		return $this->get_driver()->sql_query($query, $cache_ttl);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function cast_expr_to_string($expression)
+	{
+		return $this->get_driver()->cast_expr_to_string($expression);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		throw new \Exception('Disabled method.');
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_bit_and($column_name, $bit, $compare = '')
+	{
+		return $this->get_driver()->sql_bit_and($column_name, $bit, $compare);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_freeresult($query_id = false)
+	{
+		return $this->get_driver()->sql_freeresult($query_id);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_num_queries($cached = false)
+	{
+		return $this->get_driver()->sql_num_queries($cached);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_multi_insert($table, $sql_ary)
+	{
+		return $this->get_driver()->sql_multi_insert($table, $sql_ary);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_affectedrows()
+	{
+		return $this->get_driver()->sql_affectedrows();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_close()
+	{
+		return $this->get_driver()->sql_close();
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_rowseek($rownum, &$query_id)
+	{
+		return $this->get_driver()->sql_rowseek($rownum, $query_id);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_escape($msg)
+	{
+		return $this->get_driver()->sql_escape($msg);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_like_expression($expression)
+	{
+		return $this->get_driver()->sql_like_expression($expression);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_not_like_expression($expression)
+	{
+		return $this->get_driver()->sql_not_like_expression($expression);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_report($mode, $query = '')
+	{
+		return $this->get_driver()->sql_report($mode, $query);
+	}
+
+	/**
+	* {@inheritdoc}
+	*/
+	public function sql_in_set($field, $array, $negate = false, $allow_empty_set = false)
+	{
+		return $this->get_driver()->sql_in_set($field, $array, $negate, $allow_empty_set);
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mssql.php b/phpBB/phpbb/db/driver/mssql.php
new file mode 100644
index 0000000000..f9ea884ce2
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mssql.php
@@ -0,0 +1,476 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* MSSQL Database Abstraction Layer
+* Minimum Requirement is MSSQL 2000+
+*/
+class mssql extends \phpbb\db\driver\driver
+{
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		if (!function_exists('mssql_connect'))
+		{
+			$this->connect_error = 'mssql_connect function does not exist, is mssql extension installed?';
+			return $this->sql_error('');
+		}
+
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+		$this->dbname = $database;
+
+		$port_delimiter = (defined('PHP_OS') && substr(PHP_OS, 0, 3) === 'WIN') ? ',' : ':';
+		$this->server = $sqlserver . (($port) ? $port_delimiter . $port : '');
+
+		@ini_set('mssql.charset', 'UTF-8');
+		@ini_set('mssql.textlimit', 2147483647);
+		@ini_set('mssql.textsize', 2147483647);
+
+		$this->db_connect_id = ($this->persistency) ? @mssql_pconnect($this->server, $this->user, $sqlpassword, $new_link) : @mssql_connect($this->server, $this->user, $sqlpassword, $new_link);
+
+		if ($this->db_connect_id && $this->dbname != '')
+		{
+			if (!@mssql_select_db($this->dbname, $this->db_connect_id))
+			{
+				@mssql_close($this->db_connect_id);
+				return false;
+			}
+		}
+
+		return ($this->db_connect_id) ? $this->db_connect_id : $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mssql_version')) === false)
+		{
+			$result_id = @mssql_query("SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY('productlevel'), SERVERPROPERTY('edition')", $this->db_connect_id);
+
+			$row = false;
+			if ($result_id)
+			{
+				$row = @mssql_fetch_assoc($result_id);
+				@mssql_free_result($result_id);
+			}
+
+			$this->sql_server_version = ($row) ? trim(implode(' ', $row)) : 0;
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('mssql_version', $this->sql_server_version);
+			}
+		}
+
+		if ($raw)
+		{
+			return $this->sql_server_version;
+		}
+
+		return ($this->sql_server_version) ? 'MSSQL<br />' . $this->sql_server_version : 'MSSQL';
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' + ' . $expr2;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return @mssql_query('BEGIN TRANSACTION', $this->db_connect_id);
+			break;
+
+			case 'commit':
+				return @mssql_query('COMMIT TRANSACTION', $this->db_connect_id);
+			break;
+
+			case 'rollback':
+				return @mssql_query('ROLLBACK TRANSACTION', $this->db_connect_id);
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @mssql_query($query, $this->db_connect_id)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// Since TOP is only returning a set number of rows we won't need it if total is set to 0 (return all rows)
+		if ($total)
+		{
+			// We need to grab the total number of rows + the offset number of rows to get the correct result
+			if (strpos($query, 'SELECT DISTINCT') === 0)
+			{
+				$query = 'SELECT DISTINCT TOP ' . ($total + $offset) . ' ' . substr($query, 15);
+			}
+			else
+			{
+				$query = 'SELECT TOP ' . ($total + $offset) . ' ' . substr($query, 6);
+			}
+		}
+
+		$result = $this->sql_query($query, $cache_ttl);
+
+		// Seek by $offset rows
+		if ($offset)
+		{
+			$this->sql_rowseek($offset, $result);
+		}
+
+		return $result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->db_connect_id) ? @mssql_rows_affected($this->db_connect_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		$row = @mssql_fetch_assoc($query_id);
+
+		// I hope i am able to remove this later... hopefully only a PHP or MSSQL bug
+		if ($row)
+		{
+			foreach ($row as $key => $value)
+			{
+				$row[$key] = ($value === ' ' || $value === null) ? '' : $value;
+			}
+		}
+
+		return $row;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		return ($query_id !== false) ? @mssql_data_seek($query_id, $rownum) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		$result_id = @mssql_query('SELECT SCOPE_IDENTITY()', $this->db_connect_id);
+		if ($result_id)
+		{
+			if ($row = @mssql_fetch_assoc($result_id))
+			{
+				@mssql_free_result($result_id);
+				return $row['computed'];
+			}
+			@mssql_free_result($result_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if (isset($this->open_queries[(int) $query_id]))
+		{
+			unset($this->open_queries[(int) $query_id]);
+			return @mssql_free_result($query_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		return str_replace(array("'", "\0"), array("''", ''), $msg);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
+	/**
+	* Build LIKE expression
+	* @access private
+	*/
+	function _sql_like_expression($expression)
+	{
+		return $expression . " ESCAPE '\\'";
+	}
+
+	/**
+	* Build NOT LIKE expression
+	* @access private
+	*/
+	function _sql_not_like_expression($expression)
+	{
+		return $expression . " ESCAPE '\\'";
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if (function_exists('mssql_get_last_message'))
+		{
+			$error = array(
+				'message'	=> @mssql_get_last_message(),
+				'code'		=> '',
+			);
+
+			// Get error code number
+			$result_id = @mssql_query('SELECT @@ERROR as code', $this->db_connect_id);
+			if ($result_id)
+			{
+				$row = @mssql_fetch_assoc($result_id);
+				$error['code'] = $row['code'];
+				@mssql_free_result($result_id);
+			}
+
+			// Get full error message if possible
+			$sql = 'SELECT CAST(description as varchar(255)) as message
+				FROM master.dbo.sysmessages
+				WHERE error = ' . $error['code'];
+			$result_id = @mssql_query($sql);
+
+			if ($result_id)
+			{
+				$row = @mssql_fetch_assoc($result_id);
+				if (!empty($row['message']))
+				{
+					$error['message'] .= '<br />' . $row['message'];
+				}
+				@mssql_free_result($result_id);
+			}
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Build db-specific query data
+	* @access private
+	*/
+	function _sql_custom_build($stage, $data)
+	{
+		return $data;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @mssql_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+				$html_table = false;
+				@mssql_query('SET SHOWPLAN_TEXT ON;', $this->db_connect_id);
+				if ($result = @mssql_query($query, $this->db_connect_id))
+				{
+					@mssql_next_result($result);
+					while ($row = @mssql_fetch_row($result))
+					{
+						$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+					}
+				}
+				@mssql_query('SET SHOWPLAN_TEXT OFF;', $this->db_connect_id);
+				@mssql_free_result($result);
+
+				if ($html_table)
+				{
+					$this->html_hold .= '</table>';
+				}
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @mssql_query($query, $this->db_connect_id);
+				while ($void = @mssql_fetch_assoc($result))
+				{
+					// Take the time spent on parsing rows into account
+				}
+				@mssql_free_result($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mssql_base.php b/phpBB/phpbb/db/driver/mssql_base.php
new file mode 100644
index 0000000000..514df9eaca
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mssql_base.php
@@ -0,0 +1,71 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* MSSQL Database Base Abstraction Layer
+ */
+abstract class mssql_base extends \phpbb\db\driver\driver
+{
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return $expr1 . ' + ' . $expr2;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		return str_replace(array("'", "\0"), array("''", ''), $msg);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
+	/**
+	* Build LIKE expression
+	* @access private
+	*/
+	function _sql_like_expression($expression)
+	{
+		return $expression . " ESCAPE '\\'";
+	}
+
+	/**
+	* Build NOT LIKE expression
+	* @access private
+	*/
+	function _sql_not_like_expression($expression)
+	{
+		return $expression . " ESCAPE '\\'";
+	}
+
+	/**
+	* Build db-specific query data
+	* @access private
+	*/
+	function _sql_custom_build($stage, $data)
+	{
+		return $data;
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mssql_odbc.php b/phpBB/phpbb/db/driver/mssql_odbc.php
new file mode 100644
index 0000000000..8e5d4c7a4c
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mssql_odbc.php
@@ -0,0 +1,377 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* Unified ODBC functions
+* Unified ODBC functions support any database having ODBC driver, for example Adabas D, IBM DB2, iODBC, Solid, Sybase SQL Anywhere...
+* Here we only support MSSQL Server 2000+ because of the provided schema
+*
+* @note number of bytes returned for returning data depends on odbc.defaultlrl php.ini setting.
+* If it is limited to 4K for example only 4K of data is returned max, resulting in incomplete theme data for example.
+* @note odbc.defaultbinmode may affect UTF8 characters
+*/
+class mssql_odbc extends \phpbb\db\driver\mssql_base
+{
+	var $last_query_text = '';
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+		$this->dbname = $database;
+
+		$port_delimiter = (defined('PHP_OS') && substr(PHP_OS, 0, 3) === 'WIN') ? ',' : ':';
+		$this->server = $sqlserver . (($port) ? $port_delimiter . $port : '');
+
+		$max_size = @ini_get('odbc.defaultlrl');
+		if (!empty($max_size))
+		{
+			$unit = strtolower(substr($max_size, -1, 1));
+			$max_size = (int) $max_size;
+
+			if ($unit == 'k')
+			{
+				$max_size = floor($max_size / 1024);
+			}
+			else if ($unit == 'g')
+			{
+				$max_size *= 1024;
+			}
+			else if (is_numeric($unit))
+			{
+				$max_size = floor((int) ($max_size . $unit) / 1048576);
+			}
+			$max_size = max(8, $max_size) . 'M';
+
+			@ini_set('odbc.defaultlrl', $max_size);
+		}
+
+		if ($this->persistency)
+		{
+			if (!function_exists('odbc_pconnect'))
+			{
+				$this->connect_error = 'odbc_pconnect function does not exist, is odbc extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @odbc_pconnect($this->server, $this->user, $sqlpassword);
+		}
+		else
+		{
+			if (!function_exists('odbc_connect'))
+			{
+				$this->connect_error = 'odbc_connect function does not exist, is odbc extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @odbc_connect($this->server, $this->user, $sqlpassword);
+		}
+
+		return ($this->db_connect_id) ? $this->db_connect_id : $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mssqlodbc_version')) === false)
+		{
+			$result_id = @odbc_exec($this->db_connect_id, "SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY('productlevel'), SERVERPROPERTY('edition')");
+
+			$row = false;
+			if ($result_id)
+			{
+				$row = @odbc_fetch_array($result_id);
+				@odbc_free_result($result_id);
+			}
+
+			$this->sql_server_version = ($row) ? trim(implode(' ', $row)) : 0;
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('mssqlodbc_version', $this->sql_server_version);
+			}
+		}
+
+		if ($raw)
+		{
+			return $this->sql_server_version;
+		}
+
+		return ($this->sql_server_version) ? 'MSSQL (ODBC)<br />' . $this->sql_server_version : 'MSSQL (ODBC)';
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return @odbc_exec($this->db_connect_id, 'BEGIN TRANSACTION');
+			break;
+
+			case 'commit':
+				return @odbc_exec($this->db_connect_id, 'COMMIT TRANSACTION');
+			break;
+
+			case 'rollback':
+				return @odbc_exec($this->db_connect_id, 'ROLLBACK TRANSACTION');
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->last_query_text = $query;
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @odbc_exec($this->db_connect_id, $query)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// Since TOP is only returning a set number of rows we won't need it if total is set to 0 (return all rows)
+		if ($total)
+		{
+			// We need to grab the total number of rows + the offset number of rows to get the correct result
+			if (strpos($query, 'SELECT DISTINCT') === 0)
+			{
+				$query = 'SELECT DISTINCT TOP ' . ($total + $offset) . ' ' . substr($query, 15);
+			}
+			else
+			{
+				$query = 'SELECT TOP ' . ($total + $offset) . ' ' . substr($query, 6);
+			}
+		}
+
+		$result = $this->sql_query($query, $cache_ttl);
+
+		// Seek by $offset rows
+		if ($offset)
+		{
+			$this->sql_rowseek($offset, $result);
+		}
+
+		return $result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->db_connect_id) ? @odbc_num_rows($this->query_result) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		return ($query_id !== false) ? @odbc_fetch_array($query_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		$result_id = @odbc_exec($this->db_connect_id, 'SELECT @@IDENTITY');
+
+		if ($result_id)
+		{
+			if (@odbc_fetch_array($result_id))
+			{
+				$id = @odbc_result($result_id, 1);
+				@odbc_free_result($result_id);
+				return $id;
+			}
+			@odbc_free_result($result_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if (isset($this->open_queries[(int) $query_id]))
+		{
+			unset($this->open_queries[(int) $query_id]);
+			return @odbc_free_result($query_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if (function_exists('odbc_errormsg'))
+		{
+			$error = array(
+				'message'	=> @odbc_errormsg(),
+				'code'		=> @odbc_error(),
+			);
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @odbc_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @odbc_exec($this->db_connect_id, $query);
+				while ($void = @odbc_fetch_array($result))
+				{
+					// Take the time spent on parsing rows into account
+				}
+				@odbc_free_result($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mssqlnative.php b/phpBB/phpbb/db/driver/mssqlnative.php
new file mode 100644
index 0000000000..46a9b3a477
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mssqlnative.php
@@ -0,0 +1,442 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+/**
+* This is the MS SQL Server Native database abstraction layer.
+* PHP mssql native driver required.
+* @author Chris Pucci
+*
+*/
+
+namespace phpbb\db\driver;
+
+class mssqlnative extends \phpbb\db\driver\mssql_base
+{
+	var $m_insert_id = null;
+	var $last_query_text = '';
+	var $query_options = array();
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		// Test for driver support, to avoid suppressed fatal error
+		if (!function_exists('sqlsrv_connect'))
+		{
+			$this->connect_error = 'Native MS SQL Server driver for PHP is missing or needs to be updated. Version 1.1 or later is required to install phpBB3. You can download the driver from: http://www.microsoft.com/sqlserver/2005/en/us/PHP-Driver.aspx';
+			return $this->sql_error('');
+		}
+
+		//set up connection variables
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+		$this->dbname = $database;
+		$port_delimiter = (defined('PHP_OS') && substr(PHP_OS, 0, 3) === 'WIN') ? ',' : ':';
+		$this->server = $sqlserver . (($port) ? $port_delimiter . $port : '');
+
+		//connect to database
+		$this->db_connect_id = sqlsrv_connect($this->server, array(
+			'Database' => $this->dbname,
+			'UID' => $this->user,
+			'PWD' => $sqlpassword
+		));
+
+		return ($this->db_connect_id) ? $this->db_connect_id : $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mssql_version')) === false)
+		{
+			$arr_server_info = sqlsrv_server_info($this->db_connect_id);
+			$this->sql_server_version = $arr_server_info['SQLServerVersion'];
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('mssql_version', $this->sql_server_version);
+			}
+		}
+
+		if ($raw)
+		{
+			return $this->sql_server_version;
+		}
+
+		return ($this->sql_server_version) ? 'MSSQL<br />' . $this->sql_server_version : 'MSSQL';
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_buffer_nested_transactions()
+	{
+		return true;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return sqlsrv_begin_transaction($this->db_connect_id);
+			break;
+
+			case 'commit':
+				return sqlsrv_commit($this->db_connect_id);
+			break;
+
+			case 'rollback':
+				return sqlsrv_rollback($this->db_connect_id);
+			break;
+		}
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->last_query_text = $query;
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @sqlsrv_query($this->db_connect_id, $query, array(), $this->query_options)) === false)
+				{
+					$this->sql_error($query);
+				}
+				// reset options for next query
+				$this->query_options = array();
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+		return $this->query_result;
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// total == 0 means all results - not zero results
+		if ($offset == 0 && $total !== 0)
+		{
+			if (strpos($query, "SELECT") === false)
+			{
+				$query = "TOP {$total} " . $query;
+			}
+			else
+			{
+				$query = preg_replace('/SELECT(\s*DISTINCT)?/Dsi', 'SELECT$1 TOP '.$total, $query);
+			}
+		}
+		else if ($offset > 0)
+		{
+			$query = preg_replace('/SELECT(\s*DISTINCT)?/Dsi', 'SELECT$1 TOP(10000000) ', $query);
+			$query = 'SELECT *
+					FROM (SELECT sub2.*, ROW_NUMBER() OVER(ORDER BY sub2.line2) AS line3
+					FROM (SELECT 1 AS line2, sub1.* FROM (' . $query . ') AS sub1) as sub2) AS sub3';
+
+			if ($total > 0)
+			{
+				$query .= ' WHERE line3 BETWEEN ' . ($offset+1) . ' AND ' . ($offset + $total);
+			}
+			else
+			{
+				$query .= ' WHERE line3 > ' . $offset;
+			}
+		}
+
+		$result = $this->sql_query($query, $cache_ttl);
+
+		return $result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->db_connect_id) ? @sqlsrv_rows_affected($this->query_result) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		$row = @sqlsrv_fetch_array($query_id, SQLSRV_FETCH_ASSOC);
+
+		if ($row)
+		{
+			foreach ($row as $key => $value)
+			{
+				$row[$key] = ($value === ' ' || $value === null) ? '' : $value;
+			}
+
+			// remove helper values from LIMIT queries
+			if (isset($row['line2']))
+			{
+				unset($row['line2'], $row['line3']);
+			}
+		}
+		return (sizeof($row)) ? $row : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		$result_id = @sqlsrv_query($this->db_connect_id, 'SELECT @@IDENTITY');
+
+		if ($result_id !== false)
+		{
+			$row = @sqlsrv_fetch_array($result_id);
+			$id = $row[0];
+			@sqlsrv_free_stmt($result_id);
+			return $id;
+		}
+		else
+		{
+			return false;
+		}
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if (isset($this->open_queries[(int) $query_id]))
+		{
+			unset($this->open_queries[(int) $query_id]);
+			return @sqlsrv_free_stmt($query_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if (function_exists('sqlsrv_errors'))
+		{
+			$errors = @sqlsrv_errors(SQLSRV_ERR_ERRORS);
+			$error_message = '';
+			$code = 0;
+
+			if ($errors != null)
+			{
+				foreach ($errors as $error)
+				{
+					$error_message .= "SQLSTATE: " . $error['SQLSTATE'] . "\n";
+					$error_message .= "code: " . $error['code'] . "\n";
+					$code = $error['code'];
+					$error_message .= "message: " . $error['message'] . "\n";
+				}
+				$this->last_error_result = $error_message;
+				$error = $this->last_error_result;
+			}
+			else
+			{
+				$error = (isset($this->last_error_result) && $this->last_error_result) ? $this->last_error_result : array();
+			}
+
+			$error = array(
+				'message'	=> $error,
+				'code'		=> $code,
+			);
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @sqlsrv_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+				$html_table = false;
+				@sqlsrv_query($this->db_connect_id, 'SET SHOWPLAN_TEXT ON;');
+				if ($result = @sqlsrv_query($this->db_connect_id, $query))
+				{
+					@sqlsrv_next_result($result);
+					while ($row = @sqlsrv_fetch_array($result))
+					{
+						$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+					}
+				}
+				@sqlsrv_query($this->db_connect_id, 'SET SHOWPLAN_TEXT OFF;');
+				@sqlsrv_free_stmt($result);
+
+				if ($html_table)
+				{
+					$this->html_hold .= '</table>';
+				}
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @sqlsrv_query($this->db_connect_id, $query);
+				while ($void = @sqlsrv_fetch_array($result))
+				{
+					// Take the time spent on parsing rows into account
+				}
+				@sqlsrv_free_stmt($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+
+	/**
+	* Utility method used to retrieve number of rows
+	* Emulates mysql_num_rows
+	* Used in acp_database.php -> write_data_mssqlnative()
+	* Requires a static or keyset cursor to be definde via
+	* mssqlnative_set_query_options()
+	*/
+	function mssqlnative_num_rows($res)
+	{
+		if ($res !== false)
+		{
+			return sqlsrv_num_rows($res);
+		}
+		else
+		{
+			return false;
+		}
+	}
+
+	/**
+	* Allows setting mssqlnative specific query options passed to sqlsrv_query as 4th parameter.
+	*/
+	function mssqlnative_set_query_options($options)
+	{
+		$this->query_options = $options;
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mysql.php b/phpBB/phpbb/db/driver/mysql.php
new file mode 100644
index 0000000000..e93c7239e8
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mysql.php
@@ -0,0 +1,485 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* MySQL4 Database Abstraction Layer
+* Compatible with:
+* MySQL 3.23+
+* MySQL 4.0+
+* MySQL 4.1+
+* MySQL 5.0+
+*/
+class mysql extends \phpbb\db\driver\mysql_base
+{
+	var $multi_insert = true;
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+		$this->server = $sqlserver . (($port) ? ':' . $port : '');
+		$this->dbname = $database;
+
+		$this->sql_layer = 'mysql4';
+
+		if ($this->persistency)
+		{
+			if (!function_exists('mysql_pconnect'))
+			{
+				$this->connect_error = 'mysql_pconnect function does not exist, is mysql extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @mysql_pconnect($this->server, $this->user, $sqlpassword);
+		}
+		else
+		{
+			if (!function_exists('mysql_connect'))
+			{
+				$this->connect_error = 'mysql_connect function does not exist, is mysql extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @mysql_connect($this->server, $this->user, $sqlpassword, $new_link);
+		}
+
+		if ($this->db_connect_id && $this->dbname != '')
+		{
+			if (@mysql_select_db($this->dbname, $this->db_connect_id))
+			{
+				// Determine what version we are using and if it natively supports UNICODE
+				if (version_compare($this->sql_server_info(true), '4.1.0', '>='))
+				{
+					@mysql_query("SET NAMES 'utf8'", $this->db_connect_id);
+
+					// enforce strict mode on databases that support it
+					if (version_compare($this->sql_server_info(true), '5.0.2', '>='))
+					{
+						$result = @mysql_query('SELECT @@session.sql_mode AS sql_mode', $this->db_connect_id);
+						$row = @mysql_fetch_assoc($result);
+						@mysql_free_result($result);
+						$modes = array_map('trim', explode(',', $row['sql_mode']));
+
+						// TRADITIONAL includes STRICT_ALL_TABLES and STRICT_TRANS_TABLES
+						if (!in_array('TRADITIONAL', $modes))
+						{
+							if (!in_array('STRICT_ALL_TABLES', $modes))
+							{
+								$modes[] = 'STRICT_ALL_TABLES';
+							}
+
+							if (!in_array('STRICT_TRANS_TABLES', $modes))
+							{
+								$modes[] = 'STRICT_TRANS_TABLES';
+							}
+						}
+
+						$mode = implode(',', $modes);
+						@mysql_query("SET SESSION sql_mode='{$mode}'", $this->db_connect_id);
+					}
+				}
+				else if (version_compare($this->sql_server_info(true), '4.0.0', '<'))
+				{
+					$this->sql_layer = 'mysql';
+				}
+
+				return $this->db_connect_id;
+			}
+		}
+
+		return $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mysql_version')) === false)
+		{
+			$result = @mysql_query('SELECT VERSION() AS version', $this->db_connect_id);
+			$row = @mysql_fetch_assoc($result);
+			@mysql_free_result($result);
+
+			$this->sql_server_version = $row['version'];
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('mysql_version', $this->sql_server_version);
+			}
+		}
+
+		return ($raw) ? $this->sql_server_version : 'MySQL ' . $this->sql_server_version;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return @mysql_query('BEGIN', $this->db_connect_id);
+			break;
+
+			case 'commit':
+				return @mysql_query('COMMIT', $this->db_connect_id);
+			break;
+
+			case 'rollback':
+				return @mysql_query('ROLLBACK', $this->db_connect_id);
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @mysql_query($query, $this->db_connect_id)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		if ($this->db_connect_id)
+		{
+			// We always want the number of matched rows
+			// instead of changed rows, when running an update.
+			// So when mysql_info() returns the number of matched rows
+			// we return that one instead of mysql_affected_rows()
+			$mysql_info = @mysql_info($this->db_connect_id);
+			if ($mysql_info !== false)
+			{
+				$match = array();
+				preg_match('#^Rows matched: (\d)+  Changed: (\d)+  Warnings: (\d)+$#', $mysql_info, $match);
+				if (isset($match[1]))
+				{
+					return $match[1];
+				}
+			}
+
+			return @mysql_affected_rows($this->db_connect_id);
+		}
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		return ($query_id !== false) ? @mysql_fetch_assoc($query_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		return ($query_id !== false) ? @mysql_data_seek($query_id, $rownum) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		return ($this->db_connect_id) ? @mysql_insert_id($this->db_connect_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if (isset($this->open_queries[(int) $query_id]))
+		{
+			unset($this->open_queries[(int) $query_id]);
+			return @mysql_free_result($query_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		if (!$this->db_connect_id)
+		{
+			return @mysql_real_escape_string($msg);
+		}
+
+		return @mysql_real_escape_string($msg, $this->db_connect_id);
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if ($this->db_connect_id)
+		{
+			$error = array(
+				'message'	=> @mysql_error($this->db_connect_id),
+				'code'		=> @mysql_errno($this->db_connect_id),
+			);
+		}
+		else if (function_exists('mysql_error'))
+		{
+			$error = array(
+				'message'	=> @mysql_error(),
+				'code'		=> @mysql_errno(),
+			);
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @mysql_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		static $test_prof;
+
+		// current detection method, might just switch to see the existance of INFORMATION_SCHEMA.PROFILING
+		if ($test_prof === null)
+		{
+			$test_prof = false;
+			if (version_compare($this->sql_server_info(true), '5.0.37', '>=') && version_compare($this->sql_server_info(true), '5.1', '<'))
+			{
+				$test_prof = true;
+			}
+		}
+
+		switch ($mode)
+		{
+			case 'start':
+
+				$explain_query = $query;
+				if (preg_match('/UPDATE ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+				else if (preg_match('/DELETE FROM ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+
+				if (preg_match('/^SELECT/', $explain_query))
+				{
+					$html_table = false;
+
+					// begin profiling
+					if ($test_prof)
+					{
+						@mysql_query('SET profiling = 1;', $this->db_connect_id);
+					}
+
+					if ($result = @mysql_query("EXPLAIN $explain_query", $this->db_connect_id))
+					{
+						while ($row = @mysql_fetch_assoc($result))
+						{
+							$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+						}
+					}
+					@mysql_free_result($result);
+
+					if ($html_table)
+					{
+						$this->html_hold .= '</table>';
+					}
+
+					if ($test_prof)
+					{
+						$html_table = false;
+
+						// get the last profile
+						if ($result = @mysql_query('SHOW PROFILE ALL;', $this->db_connect_id))
+						{
+							$this->html_hold .= '<br />';
+							while ($row = @mysql_fetch_assoc($result))
+							{
+								// make <unknown> HTML safe
+								if (!empty($row['Source_function']))
+								{
+									$row['Source_function'] = str_replace(array('<', '>'), array('&lt;', '&gt;'), $row['Source_function']);
+								}
+
+								// remove unsupported features
+								foreach ($row as $key => $val)
+								{
+									if ($val === null)
+									{
+										unset($row[$key]);
+									}
+								}
+								$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+							}
+						}
+						@mysql_free_result($result);
+
+						if ($html_table)
+						{
+							$this->html_hold .= '</table>';
+						}
+
+						@mysql_query('SET profiling = 0;', $this->db_connect_id);
+					}
+				}
+
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @mysql_query($query, $this->db_connect_id);
+				while ($void = @mysql_fetch_assoc($result))
+				{
+					// Take the time spent on parsing rows into account
+				}
+				@mysql_free_result($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mysql_base.php b/phpBB/phpbb/db/driver/mysql_base.php
new file mode 100644
index 0000000000..5e0b359134
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mysql_base.php
@@ -0,0 +1,138 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* Abstract MySQL Database Base Abstraction Layer
+*/
+abstract class mysql_base extends \phpbb\db\driver\driver
+{
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_concatenate($expr1, $expr2)
+	{
+		return 'CONCAT(' . $expr1 . ', ' . $expr2 . ')';
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// if $total is set to 0 we do not want to limit the number of rows
+		if ($total == 0)
+		{
+			// MySQL 4.1+ no longer supports -1 in limit queries
+			$total = '18446744073709551615';
+		}
+
+		$query .= "\n LIMIT " . ((!empty($offset)) ? $offset . ', ' . $total : $total);
+
+		return $this->sql_query($query, $cache_ttl);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function get_estimated_row_count($table_name)
+	{
+		$table_status = $this->get_table_status($table_name);
+
+		if (isset($table_status['Engine']))
+		{
+			if ($table_status['Engine'] === 'MyISAM')
+			{
+				return $table_status['Rows'];
+			}
+			else if ($table_status['Engine'] === 'InnoDB' && $table_status['Rows'] > 100000)
+			{
+				return '~' . $table_status['Rows'];
+			}
+		}
+
+		return parent::get_row_count($table_name);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function get_row_count($table_name)
+	{
+		$table_status = $this->get_table_status($table_name);
+
+		if (isset($table_status['Engine']) && $table_status['Engine'] === 'MyISAM')
+		{
+			return $table_status['Rows'];
+		}
+
+		return parent::get_row_count($table_name);
+	}
+
+	/**
+	* Gets some information about the specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return array
+	*
+	* @access protected
+	*/
+	function get_table_status($table_name)
+	{
+		$sql = "SHOW TABLE STATUS
+			LIKE '" . $this->sql_escape($table_name) . "'";
+		$result = $this->sql_query($sql);
+		$table_status = $this->sql_fetchrow($result);
+		$this->sql_freeresult($result);
+
+		return $table_status;
+	}
+
+	/**
+	* Build LIKE expression
+	* @access private
+	*/
+	function _sql_like_expression($expression)
+	{
+		return $expression;
+	}
+
+	/**
+	* Build NOT LIKE expression
+	* @access private
+	*/
+	function _sql_not_like_expression($expression)
+	{
+		return $expression;
+	}
+
+	/**
+	* Build db-specific query data
+	* @access private
+	*/
+	function _sql_custom_build($stage, $data)
+	{
+		switch ($stage)
+		{
+			case 'FROM':
+				$data = '(' . $data . ')';
+			break;
+		}
+
+		return $data;
+	}
+}
diff --git a/phpBB/phpbb/db/driver/mysqli.php b/phpBB/phpbb/db/driver/mysqli.php
new file mode 100644
index 0000000000..c0ddfbf76c
--- /dev/null
+++ b/phpBB/phpbb/db/driver/mysqli.php
@@ -0,0 +1,475 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* MySQLi Database Abstraction Layer
+* mysqli-extension has to be compiled with:
+* MySQL 4.1+ or MySQL 5.0+
+*/
+class mysqli extends \phpbb\db\driver\mysql_base
+{
+	var $multi_insert = true;
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		if (!function_exists('mysqli_connect'))
+		{
+			$this->connect_error = 'mysqli_connect function does not exist, is mysqli extension installed?';
+			return $this->sql_error('');
+		}
+
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+
+		// If persistent connection, set dbhost to localhost when empty and prepend it with 'p:' prefix
+		$this->server = ($this->persistency) ? 'p:' . (($sqlserver) ? $sqlserver : 'localhost') : $sqlserver;
+
+		$this->dbname = $database;
+		$port = (!$port) ? null : $port;
+
+		// If port is set and it is not numeric, most likely mysqli socket is set.
+		// Try to map it to the $socket parameter.
+		$socket = null;
+		if ($port)
+		{
+			if (is_numeric($port))
+			{
+				$port = (int) $port;
+			}
+			else
+			{
+				$socket = $port;
+				$port = null;
+			}
+		}
+
+		$this->db_connect_id = mysqli_init();
+
+		if (!@mysqli_real_connect($this->db_connect_id, $this->server, $this->user, $sqlpassword, $this->dbname, $port, $socket, MYSQLI_CLIENT_FOUND_ROWS))
+		{
+			$this->db_connect_id = '';
+		}
+
+		if ($this->db_connect_id && $this->dbname != '')
+		{
+			@mysqli_query($this->db_connect_id, "SET NAMES 'utf8'");
+
+			// enforce strict mode on databases that support it
+			if (version_compare($this->sql_server_info(true), '5.0.2', '>='))
+			{
+				$result = @mysqli_query($this->db_connect_id, 'SELECT @@session.sql_mode AS sql_mode');
+				if ($result !== null)
+				{
+					$row = @mysqli_fetch_assoc($result);
+
+					$modes = array_map('trim', explode(',', $row['sql_mode']));
+				}
+				else
+				{
+					$modes = array();
+				}
+				@mysqli_free_result($result);
+
+				// TRADITIONAL includes STRICT_ALL_TABLES and STRICT_TRANS_TABLES
+				if (!in_array('TRADITIONAL', $modes))
+				{
+					if (!in_array('STRICT_ALL_TABLES', $modes))
+					{
+						$modes[] = 'STRICT_ALL_TABLES';
+					}
+
+					if (!in_array('STRICT_TRANS_TABLES', $modes))
+					{
+						$modes[] = 'STRICT_TRANS_TABLES';
+					}
+				}
+
+				$mode = implode(',', $modes);
+				@mysqli_query($this->db_connect_id, "SET SESSION sql_mode='{$mode}'");
+			}
+			return $this->db_connect_id;
+		}
+
+		return $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('mysqli_version')) === false)
+		{
+			$result = @mysqli_query($this->db_connect_id, 'SELECT VERSION() AS version');
+			if ($result !== null)
+			{
+				$row = @mysqli_fetch_assoc($result);
+
+				$this->sql_server_version = $row['version'];
+
+				if (!empty($cache) && $use_cache)
+				{
+					$cache->put('mysqli_version', $this->sql_server_version);
+				}
+			}
+			@mysqli_free_result($result);
+		}
+
+		return ($raw) ? $this->sql_server_version : 'MySQL(i) ' . $this->sql_server_version;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return @mysqli_autocommit($this->db_connect_id, false);
+			break;
+
+			case 'commit':
+				$result = @mysqli_commit($this->db_connect_id);
+				@mysqli_autocommit($this->db_connect_id, true);
+				return $result;
+			break;
+
+			case 'rollback':
+				$result = @mysqli_rollback($this->db_connect_id);
+				@mysqli_autocommit($this->db_connect_id, true);
+				return $result;
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @mysqli_query($this->db_connect_id, $query)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->db_connect_id) ? @mysqli_affected_rows($this->db_connect_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		if ($query_id !== false && $query_id !== null)
+		{
+			$result = @mysqli_fetch_assoc($query_id);
+			return $result !== null ? $result : false;
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		return ($query_id !== false) ? @mysqli_data_seek($query_id, $rownum) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		return ($this->db_connect_id) ? @mysqli_insert_id($this->db_connect_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		return @mysqli_free_result($query_id);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		return @mysqli_real_escape_string($this->db_connect_id, $msg);
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if ($this->db_connect_id)
+		{
+			$error = array(
+				'message'	=> @mysqli_error($this->db_connect_id),
+				'code'		=> @mysqli_errno($this->db_connect_id)
+			);
+		}
+		else if (function_exists('mysqli_connect_error'))
+		{
+			$error = array(
+				'message'	=> @mysqli_connect_error(),
+				'code'		=> @mysqli_connect_errno(),
+			);
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @mysqli_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		static $test_prof;
+
+		// current detection method, might just switch to see the existance of INFORMATION_SCHEMA.PROFILING
+		if ($test_prof === null)
+		{
+			$test_prof = false;
+			if (strpos(mysqli_get_server_info($this->db_connect_id), 'community') !== false)
+			{
+				$ver = mysqli_get_server_version($this->db_connect_id);
+				if ($ver >= 50037 && $ver < 50100)
+				{
+					$test_prof = true;
+				}
+			}
+		}
+
+		switch ($mode)
+		{
+			case 'start':
+
+				$explain_query = $query;
+				if (preg_match('/UPDATE ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+				else if (preg_match('/DELETE FROM ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+
+				if (preg_match('/^SELECT/', $explain_query))
+				{
+					$html_table = false;
+
+					// begin profiling
+					if ($test_prof)
+					{
+						@mysqli_query($this->db_connect_id, 'SET profiling = 1;');
+					}
+
+					if ($result = @mysqli_query($this->db_connect_id, "EXPLAIN $explain_query"))
+					{
+						while ($row = @mysqli_fetch_assoc($result))
+						{
+							$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+						}
+					}
+					@mysqli_free_result($result);
+
+					if ($html_table)
+					{
+						$this->html_hold .= '</table>';
+					}
+
+					if ($test_prof)
+					{
+						$html_table = false;
+
+						// get the last profile
+						if ($result = @mysqli_query($this->db_connect_id, 'SHOW PROFILE ALL;'))
+						{
+							$this->html_hold .= '<br />';
+							while ($row = @mysqli_fetch_assoc($result))
+							{
+								// make <unknown> HTML safe
+								if (!empty($row['Source_function']))
+								{
+									$row['Source_function'] = str_replace(array('<', '>'), array('&lt;', '&gt;'), $row['Source_function']);
+								}
+
+								// remove unsupported features
+								foreach ($row as $key => $val)
+								{
+									if ($val === null)
+									{
+										unset($row[$key]);
+									}
+								}
+								$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+							}
+						}
+						@mysqli_free_result($result);
+
+						if ($html_table)
+						{
+							$this->html_hold .= '</table>';
+						}
+
+						@mysqli_query($this->db_connect_id, 'SET profiling = 0;');
+					}
+				}
+
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @mysqli_query($this->db_connect_id, $query);
+				if ($result !== null)
+				{
+					while ($void = @mysqli_fetch_assoc($result))
+					{
+						// Take the time spent on parsing rows into account
+					}
+				}
+				@mysqli_free_result($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/oracle.php b/phpBB/phpbb/db/driver/oracle.php
new file mode 100644
index 0000000000..6dcab5dd7d
--- /dev/null
+++ b/phpBB/phpbb/db/driver/oracle.php
@@ -0,0 +1,807 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* Oracle Database Abstraction Layer
+*/
+class oracle extends \phpbb\db\driver\driver
+{
+	var $last_query_text = '';
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+		$this->server = $sqlserver . (($port) ? ':' . $port : '');
+		$this->dbname = $database;
+
+		$connect = $database;
+
+		// support for "easy connect naming"
+		if ($sqlserver !== '' && $sqlserver !== '/')
+		{
+			if (substr($sqlserver, -1, 1) == '/')
+			{
+				$sqlserver == substr($sqlserver, 0, -1);
+			}
+			$connect = $sqlserver . (($port) ? ':' . $port : '') . '/' . $database;
+		}
+
+		if ($new_link)
+		{
+			if (!function_exists('ocinlogon'))
+			{
+				$this->connect_error = 'ocinlogon function does not exist, is oci extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @ocinlogon($this->user, $sqlpassword, $connect, 'UTF8');
+		}
+		else if ($this->persistency)
+		{
+			if (!function_exists('ociplogon'))
+			{
+				$this->connect_error = 'ociplogon function does not exist, is oci extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @ociplogon($this->user, $sqlpassword, $connect, 'UTF8');
+		}
+		else
+		{
+			if (!function_exists('ocilogon'))
+			{
+				$this->connect_error = 'ocilogon function does not exist, is oci extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @ocilogon($this->user, $sqlpassword, $connect, 'UTF8');
+		}
+
+		return ($this->db_connect_id) ? $this->db_connect_id : $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		/**
+		* force $use_cache false.  I didn't research why the caching code below is commented out
+		* but I assume its because the Oracle extension provides a direct method to access it
+		* without a query.
+		*/
+
+		$use_cache = false;
+/*
+		global $cache;
+
+		if (empty($cache) || ($this->sql_server_version = $cache->get('oracle_version')) === false)
+		{
+			$result = @ociparse($this->db_connect_id, 'SELECT * FROM v$version WHERE banner LIKE \'Oracle%\'');
+			@ociexecute($result, OCI_DEFAULT);
+			@ocicommit($this->db_connect_id);
+
+			$row = array();
+			@ocifetchinto($result, $row, OCI_ASSOC + OCI_RETURN_NULLS);
+			@ocifreestatement($result);
+			$this->sql_server_version = trim($row['BANNER']);
+
+			$cache->put('oracle_version', $this->sql_server_version);
+		}
+*/
+		$this->sql_server_version = @ociserverversion($this->db_connect_id);
+
+		return $this->sql_server_version;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return true;
+			break;
+
+			case 'commit':
+				return @ocicommit($this->db_connect_id);
+			break;
+
+			case 'rollback':
+				return @ocirollback($this->db_connect_id);
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* Oracle specific code to handle the fact that it does not compare columns properly
+	* @access private
+	*/
+	function _rewrite_col_compare($args)
+	{
+		if (sizeof($args) == 4)
+		{
+			if ($args[2] == '=')
+			{
+				return '(' . $args[0] . ' OR (' . $args[1] . ' is NULL AND ' . $args[3] . ' is NULL))';
+			}
+			else if ($args[2] == '<>')
+			{
+				// really just a fancy way of saying foo <> bar or (foo is NULL XOR bar is NULL) but SQL has no XOR :P
+				return '(' . $args[0] . ' OR ((' . $args[1] . ' is NULL AND ' . $args[3] . ' is NOT NULL) OR (' . $args[1] . ' is NOT NULL AND ' . $args[3] . ' is NULL)))';
+			}
+		}
+		else
+		{
+			return $this->_rewrite_where($args[0]);
+		}
+	}
+
+	/**
+	* Oracle specific code to handle it's lack of sanity
+	* @access private
+	*/
+	function _rewrite_where($where_clause)
+	{
+		preg_match_all('/\s*(AND|OR)?\s*([\w_.()]++)\s*(?:(=|<[=>]?|>=?|LIKE)\s*((?>\'(?>[^\']++|\'\')*+\'|[\d-.()]+))|((NOT )?IN\s*\((?>\'(?>[^\']++|\'\')*+\',? ?|[\d-.]+,? ?)*+\)))/', $where_clause, $result, PREG_SET_ORDER);
+		$out = '';
+		foreach ($result as $val)
+		{
+			if (!isset($val[5]))
+			{
+				if ($val[4] !== "''")
+				{
+					$out .= $val[0];
+				}
+				else
+				{
+					$out .= ' ' . $val[1] . ' ' . $val[2];
+					if ($val[3] == '=')
+					{
+						$out .= ' is NULL';
+					}
+					else if ($val[3] == '<>')
+					{
+						$out .= ' is NOT NULL';
+					}
+				}
+			}
+			else
+			{
+				$in_clause = array();
+				$sub_exp = substr($val[5], strpos($val[5], '(') + 1, -1);
+				$extra = false;
+				preg_match_all('/\'(?>[^\']++|\'\')*+\'|[\d-.]++/', $sub_exp, $sub_vals, PREG_PATTERN_ORDER);
+				$i = 0;
+				foreach ($sub_vals[0] as $sub_val)
+				{
+					// two things:
+					// 1) This determines if an empty string was in the IN clausing, making us turn it into a NULL comparison
+					// 2) This fixes the 1000 list limit that Oracle has (ORA-01795)
+					if ($sub_val !== "''")
+					{
+						$in_clause[(int) $i++/1000][] = $sub_val;
+					}
+					else
+					{
+						$extra = true;
+					}
+				}
+				if (!$extra && $i < 1000)
+				{
+					$out .= $val[0];
+				}
+				else
+				{
+					$out .= ' ' . $val[1] . '(';
+					$in_array = array();
+
+					// constuct each IN() clause
+					foreach ($in_clause as $in_values)
+					{
+						$in_array[] = $val[2] . ' ' . (isset($val[6]) ? $val[6] : '') . 'IN(' . implode(', ', $in_values) . ')';
+					}
+
+					// Join the IN() clauses against a few ORs (IN is just a nicer OR anyway)
+					$out .= implode(' OR ', $in_array);
+
+					// handle the empty string case
+					if ($extra)
+					{
+						$out .= ' OR ' . $val[2] . ' is ' . (isset($val[6]) ? $val[6] : '') . 'NULL';
+					}
+					$out .= ')';
+
+					unset($in_array, $in_clause);
+				}
+			}
+		}
+
+		return $out;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->last_query_text = $query;
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				$in_transaction = false;
+				if (!$this->transaction)
+				{
+					$this->sql_transaction('begin');
+				}
+				else
+				{
+					$in_transaction = true;
+				}
+
+				$array = array();
+
+				// We overcome Oracle's 4000 char limit by binding vars
+				if (strlen($query) > 4000)
+				{
+					if (preg_match('/^(INSERT INTO[^(]++)\\(([^()]+)\\) VALUES[^(]++\\((.*?)\\)$/sU', $query, $regs))
+					{
+						if (strlen($regs[3]) > 4000)
+						{
+							$cols = explode(', ', $regs[2]);
+
+							preg_match_all('/\'(?:[^\']++|\'\')*+\'|[\d-.]+/', $regs[3], $vals, PREG_PATTERN_ORDER);
+
+/*						The code inside this comment block breaks clob handling, but does allow the
+						database restore script to work.  If you want to allow no posts longer than 4KB
+						and/or need the db restore script, uncomment this.
+
+
+							if (sizeof($cols) !== sizeof($vals))
+							{
+								// Try to replace some common data we know is from our restore script or from other sources
+								$regs[3] = str_replace("'||chr(47)||'", '/', $regs[3]);
+								$_vals = explode(', ', $regs[3]);
+
+								$vals = array();
+								$is_in_val = false;
+								$i = 0;
+								$string = '';
+
+								foreach ($_vals as $value)
+								{
+									if (strpos($value, "'") === false && !$is_in_val)
+									{
+										$vals[$i++] = $value;
+										continue;
+									}
+
+									if (substr($value, -1) === "'")
+									{
+										$vals[$i] = $string . (($is_in_val) ? ', ' : '') . $value;
+										$string = '';
+										$is_in_val = false;
+
+										if ($vals[$i][0] !== "'")
+										{
+											$vals[$i] = "''" . $vals[$i];
+										}
+										$i++;
+										continue;
+									}
+									else
+									{
+										$string .= (($is_in_val) ? ', ' : '') . $value;
+										$is_in_val = true;
+									}
+								}
+
+								if ($string)
+								{
+									// New value if cols != value
+									$vals[(sizeof($cols) !== sizeof($vals)) ? $i : $i - 1] .= $string;
+								}
+
+								$vals = array(0 => $vals);
+							}
+*/
+
+							$inserts = $vals[0];
+							unset($vals);
+
+							foreach ($inserts as $key => $value)
+							{
+								if (!empty($value) && $value[0] === "'" && strlen($value) > 4002) // check to see if this thing is greater than the max + 'x2
+								{
+									$inserts[$key] = ':' . strtoupper($cols[$key]);
+									$array[$inserts[$key]] = str_replace("''", "'", substr($value, 1, -1));
+								}
+							}
+
+							$query = $regs[1] . '(' . $regs[2] . ') VALUES (' . implode(', ', $inserts) . ')';
+						}
+					}
+					else if (preg_match_all('/^(UPDATE [\\w_]++\\s+SET )([\\w_]++\\s*=\\s*(?:\'(?:[^\']++|\'\')*+\'|[\d-.]+)(?:,\\s*[\\w_]++\\s*=\\s*(?:\'(?:[^\']++|\'\')*+\'|[\d-.]+))*+)\\s+(WHERE.*)$/s', $query, $data, PREG_SET_ORDER))
+					{
+						if (strlen($data[0][2]) > 4000)
+						{
+							$update = $data[0][1];
+							$where = $data[0][3];
+							preg_match_all('/([\\w_]++)\\s*=\\s*(\'(?:[^\']++|\'\')*+\'|[\d-.]++)/', $data[0][2], $temp, PREG_SET_ORDER);
+							unset($data);
+
+							$cols = array();
+							foreach ($temp as $value)
+							{
+								if (!empty($value[2]) && $value[2][0] === "'" && strlen($value[2]) > 4002) // check to see if this thing is greater than the max + 'x2
+								{
+									$cols[] = $value[1] . '=:' . strtoupper($value[1]);
+									$array[$value[1]] = str_replace("''", "'", substr($value[2], 1, -1));
+								}
+								else
+								{
+									$cols[] = $value[1] . '=' . $value[2];
+								}
+							}
+
+							$query = $update . implode(', ', $cols) . ' ' . $where;
+							unset($cols);
+						}
+					}
+				}
+
+				switch (substr($query, 0, 6))
+				{
+					case 'DELETE':
+						if (preg_match('/^(DELETE FROM [\w_]++ WHERE)((?:\s*(?:AND|OR)?\s*[\w_]+\s*(?:(?:=|<>)\s*(?>\'(?>[^\']++|\'\')*+\'|[\d-.]+)|(?:NOT )?IN\s*\((?>\'(?>[^\']++|\'\')*+\',? ?|[\d-.]+,? ?)*+\)))*+)$/', $query, $regs))
+						{
+							$query = $regs[1] . $this->_rewrite_where($regs[2]);
+							unset($regs);
+						}
+					break;
+
+					case 'UPDATE':
+						if (preg_match('/^(UPDATE [\\w_]++\\s+SET [\\w_]+\s*=\s*(?:\'(?:[^\']++|\'\')*+\'|[\d-.]++|:\w++)(?:, [\\w_]+\s*=\s*(?:\'(?:[^\']++|\'\')*+\'|[\d-.]++|:\w++))*+\\s+WHERE)(.*)$/s',  $query, $regs))
+						{
+							$query = $regs[1] . $this->_rewrite_where($regs[2]);
+							unset($regs);
+						}
+					break;
+
+					case 'SELECT':
+						$query = preg_replace_callback('/([\w_.]++)\s*(?:(=|<>)\s*(?>\'(?>[^\']++|\'\')*+\'|[\d-.]++|([\w_.]++))|(?:NOT )?IN\s*\((?>\'(?>[^\']++|\'\')*+\',? ?|[\d-.]++,? ?)*+\))/', array($this, '_rewrite_col_compare'), $query);
+					break;
+				}
+
+				$this->query_result = @ociparse($this->db_connect_id, $query);
+
+				foreach ($array as $key => $value)
+				{
+					@ocibindbyname($this->query_result, $key, $array[$key], -1);
+				}
+
+				$success = @ociexecute($this->query_result, OCI_DEFAULT);
+
+				if (!$success)
+				{
+					$this->sql_error($query);
+					$this->query_result = false;
+				}
+				else
+				{
+					if (!$in_transaction)
+					{
+						$this->sql_transaction('commit');
+					}
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		$query = 'SELECT * FROM (SELECT /*+ FIRST_ROWS */ rownum AS xrownum, a.* FROM (' . $query . ') a WHERE rownum <= ' . ($offset + $total) . ') WHERE xrownum >= ' . $offset;
+
+		return $this->sql_query($query, $cache_ttl);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->query_result) ? @ocirowcount($this->query_result) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		if ($query_id !== false)
+		{
+			$row = array();
+			$result = @ocifetchinto($query_id, $row, OCI_ASSOC + OCI_RETURN_NULLS);
+
+			if (!$result || !$row)
+			{
+				return false;
+			}
+
+			$result_row = array();
+			foreach ($row as $key => $value)
+			{
+				// Oracle treats empty strings as null
+				if (is_null($value))
+				{
+					$value = '';
+				}
+
+				// OCI->CLOB?
+				if (is_object($value))
+				{
+					$value = $value->load();
+				}
+
+				$result_row[strtolower($key)] = $value;
+			}
+
+			return $result_row;
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		// Reset internal pointer
+		@ociexecute($query_id, OCI_DEFAULT);
+
+		// We do not fetch the row for rownum == 0 because then the next resultset would be the second row
+		for ($i = 0; $i < $rownum; $i++)
+		{
+			if (!$this->sql_fetchrow($query_id))
+			{
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		$query_id = $this->query_result;
+
+		if ($query_id !== false && $this->last_query_text != '')
+		{
+			if (preg_match('#^INSERT[\t\n ]+INTO[\t\n ]+([a-z0-9\_\-]+)#is', $this->last_query_text, $tablename))
+			{
+				$query = 'SELECT ' . $tablename[1] . '_seq.currval FROM DUAL';
+				$stmt = @ociparse($this->db_connect_id, $query);
+				@ociexecute($stmt, OCI_DEFAULT);
+
+				$temp_result = @ocifetchinto($stmt, $temp_array, OCI_ASSOC + OCI_RETURN_NULLS);
+				@ocifreestatement($stmt);
+
+				if ($temp_result)
+				{
+					return $temp_array['CURRVAL'];
+				}
+				else
+				{
+					return false;
+				}
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if (isset($this->open_queries[(int) $query_id]))
+		{
+			unset($this->open_queries[(int) $query_id]);
+			return @ocifreestatement($query_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		return str_replace(array("'", "\0"), array("''", ''), $msg);
+	}
+
+	/**
+	* Build LIKE expression
+	* @access private
+	*/
+	function _sql_like_expression($expression)
+	{
+		return $expression . " ESCAPE '\\'";
+	}
+
+	/**
+	* Build NOT LIKE expression
+	* @access private
+	*/
+	function _sql_not_like_expression($expression)
+	{
+		return $expression . " ESCAPE '\\'";
+	}
+
+	function _sql_custom_build($stage, $data)
+	{
+		return $data;
+	}
+
+	function _sql_bit_and($column_name, $bit, $compare = '')
+	{
+		return 'BITAND(' . $column_name . ', ' . (1 << $bit) . ')' . (($compare) ? ' ' . $compare : '');
+	}
+
+	function _sql_bit_or($column_name, $bit, $compare = '')
+	{
+		return 'BITOR(' . $column_name . ', ' . (1 << $bit) . ')' . (($compare) ? ' ' . $compare : '');
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if (function_exists('ocierror'))
+		{
+			$error = @ocierror();
+			$error = (!$error) ? @ocierror($this->query_result) : $error;
+			$error = (!$error) ? @ocierror($this->db_connect_id) : $error;
+
+			if ($error)
+			{
+				$this->last_error_result = $error;
+			}
+			else
+			{
+				$error = (isset($this->last_error_result) && $this->last_error_result) ? $this->last_error_result : array();
+			}
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @ocilogoff($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+
+				$html_table = false;
+
+				// Grab a plan table, any will do
+				$sql = "SELECT table_name
+					FROM USER_TABLES
+					WHERE table_name LIKE '%PLAN_TABLE%'";
+				$stmt = ociparse($this->db_connect_id, $sql);
+				ociexecute($stmt);
+				$result = array();
+
+				if (ocifetchinto($stmt, $result, OCI_ASSOC + OCI_RETURN_NULLS))
+				{
+					$table = $result['TABLE_NAME'];
+
+					// This is the statement_id that will allow us to track the plan
+					$statement_id = substr(md5($query), 0, 30);
+
+					// Remove any stale plans
+					$stmt2 = ociparse($this->db_connect_id, "DELETE FROM $table WHERE statement_id='$statement_id'");
+					ociexecute($stmt2);
+					ocifreestatement($stmt2);
+
+					// Explain the plan
+					$sql = "EXPLAIN PLAN
+						SET STATEMENT_ID = '$statement_id'
+						FOR $query";
+					$stmt2 = ociparse($this->db_connect_id, $sql);
+					ociexecute($stmt2);
+					ocifreestatement($stmt2);
+
+					// Get the data from the plan
+					$sql = "SELECT operation, options, object_name, object_type, cardinality, cost
+						FROM plan_table
+						START WITH id = 0 AND statement_id = '$statement_id'
+						CONNECT BY PRIOR id = parent_id
+							AND statement_id = '$statement_id'";
+					$stmt2 = ociparse($this->db_connect_id, $sql);
+					ociexecute($stmt2);
+
+					$row = array();
+					while (ocifetchinto($stmt2, $row, OCI_ASSOC + OCI_RETURN_NULLS))
+					{
+						$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+					}
+
+					ocifreestatement($stmt2);
+
+					// Remove the plan we just made, we delete them on request anyway
+					$stmt2 = ociparse($this->db_connect_id, "DELETE FROM $table WHERE statement_id='$statement_id'");
+					ociexecute($stmt2);
+					ocifreestatement($stmt2);
+				}
+
+				ocifreestatement($stmt);
+
+				if ($html_table)
+				{
+					$this->html_hold .= '</table>';
+				}
+
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @ociparse($this->db_connect_id, $query);
+				$success = @ociexecute($result, OCI_DEFAULT);
+				$row = array();
+
+				while (@ocifetchinto($result, $row, OCI_ASSOC + OCI_RETURN_NULLS))
+				{
+					// Take the time spent on parsing rows into account
+				}
+				@ocifreestatement($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/postgres.php b/phpBB/phpbb/db/driver/postgres.php
new file mode 100644
index 0000000000..a3b9aa4c6b
--- /dev/null
+++ b/phpBB/phpbb/db/driver/postgres.php
@@ -0,0 +1,490 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* PostgreSQL Database Abstraction Layer
+* Minimum Requirement is Version 8.3+
+*/
+class postgres extends \phpbb\db\driver\driver
+{
+	var $multi_insert = true;
+	var $last_query_text = '';
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		$connect_string = '';
+
+		if ($sqluser)
+		{
+			$connect_string .= "user=$sqluser ";
+		}
+
+		if ($sqlpassword)
+		{
+			$connect_string .= "password=$sqlpassword ";
+		}
+
+		if ($sqlserver)
+		{
+			// $sqlserver can carry a port separated by : for compatibility reasons
+			// If $sqlserver has more than one : it's probably an IPv6 address.
+			// In this case we only allow passing a port via the $port variable.
+			if (substr_count($sqlserver, ':') === 1)
+			{
+				list($sqlserver, $port) = explode(':', $sqlserver);
+			}
+
+			if ($sqlserver !== 'localhost')
+			{
+				$connect_string .= "host=$sqlserver ";
+			}
+
+			if ($port)
+			{
+				$connect_string .= "port=$port ";
+			}
+		}
+
+		$schema = '';
+
+		if ($database)
+		{
+			$this->dbname = $database;
+			if (strpos($database, '.') !== false)
+			{
+				list($database, $schema) = explode('.', $database);
+			}
+			$connect_string .= "dbname=$database";
+		}
+
+		$this->persistency = $persistency;
+
+		if ($this->persistency)
+		{
+			if (!function_exists('pg_pconnect'))
+			{
+				$this->connect_error = 'pg_pconnect function does not exist, is pgsql extension installed?';
+				return $this->sql_error('');
+			}
+			$collector = new \phpbb\error_collector;
+			$collector->install();
+			$this->db_connect_id = (!$new_link) ? @pg_pconnect($connect_string) : @pg_pconnect($connect_string, PGSQL_CONNECT_FORCE_NEW);
+		}
+		else
+		{
+			if (!function_exists('pg_connect'))
+			{
+				$this->connect_error = 'pg_connect function does not exist, is pgsql extension installed?';
+				return $this->sql_error('');
+			}
+			$collector = new \phpbb\error_collector;
+			$collector->install();
+			$this->db_connect_id = (!$new_link) ? @pg_connect($connect_string) : @pg_connect($connect_string, PGSQL_CONNECT_FORCE_NEW);
+		}
+
+		$collector->uninstall();
+
+		if ($this->db_connect_id)
+		{
+			if ($schema !== '')
+			{
+				@pg_query($this->db_connect_id, 'SET search_path TO ' . $schema);
+			}
+			return $this->db_connect_id;
+		}
+
+		$this->connect_error = $collector->format_errors();
+		return $this->sql_error('');
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('pgsql_version')) === false)
+		{
+			$query_id = @pg_query($this->db_connect_id, 'SELECT VERSION() AS version');
+			$row = @pg_fetch_assoc($query_id, null);
+			@pg_free_result($query_id);
+
+			$this->sql_server_version = (!empty($row['version'])) ? trim(substr($row['version'], 10)) : 0;
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('pgsql_version', $this->sql_server_version);
+			}
+		}
+
+		return ($raw) ? $this->sql_server_version : 'PostgreSQL ' . $this->sql_server_version;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return @pg_query($this->db_connect_id, 'BEGIN');
+			break;
+
+			case 'commit':
+				return @pg_query($this->db_connect_id, 'COMMIT');
+			break;
+
+			case 'rollback':
+				return @pg_query($this->db_connect_id, 'ROLLBACK');
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->last_query_text = $query;
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @pg_query($this->db_connect_id, $query)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* Build db-specific query data
+	* @access private
+	*/
+	function _sql_custom_build($stage, $data)
+	{
+		return $data;
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// if $total is set to 0 we do not want to limit the number of rows
+		if ($total == 0)
+		{
+			$total = 'ALL';
+		}
+
+		$query .= "\n LIMIT $total OFFSET $offset";
+
+		return $this->sql_query($query, $cache_ttl);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->query_result) ? @pg_affected_rows($this->query_result) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		return ($query_id !== false) ? @pg_fetch_assoc($query_id, null) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		return ($query_id !== false) ? @pg_result_seek($query_id, $rownum) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		$query_id = $this->query_result;
+
+		if ($query_id !== false && $this->last_query_text != '')
+		{
+			if (preg_match("/^INSERT[\t\n ]+INTO[\t\n ]+([a-z0-9\_\-]+)/is", $this->last_query_text, $tablename))
+			{
+				$query = "SELECT currval('" . $tablename[1] . "_seq') AS last_value";
+				$temp_q_id = @pg_query($this->db_connect_id, $query);
+
+				if (!$temp_q_id)
+				{
+					return false;
+				}
+
+				$temp_result = @pg_fetch_assoc($temp_q_id, null);
+				@pg_free_result($query_id);
+
+				return ($temp_result) ? $temp_result['last_value'] : false;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if (isset($this->open_queries[(int) $query_id]))
+		{
+			unset($this->open_queries[(int) $query_id]);
+			return @pg_free_result($query_id);
+		}
+
+		return false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		return @pg_escape_string($msg);
+	}
+
+	/**
+	* Build LIKE expression
+	* @access private
+	*/
+	function _sql_like_expression($expression)
+	{
+		return $expression;
+	}
+
+	/**
+	* Build NOT LIKE expression
+	* @access private
+	*/
+	function _sql_not_like_expression($expression)
+	{
+		return $expression;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function cast_expr_to_bigint($expression)
+	{
+		return 'CAST(' . $expression . ' as DECIMAL(255, 0))';
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function cast_expr_to_string($expression)
+	{
+		return 'CAST(' . $expression . ' as VARCHAR(255))';
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		// pg_last_error only works when there is an established connection.
+		// Connection errors have to be tracked by us manually.
+		if ($this->db_connect_id)
+		{
+			$message = @pg_last_error($this->db_connect_id);
+		}
+		else
+		{
+			$message = $this->connect_error;
+		}
+
+		return array(
+			'message'	=> $message,
+			'code'		=> ''
+		);
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @pg_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+
+				$explain_query = $query;
+				if (preg_match('/UPDATE ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+				else if (preg_match('/DELETE FROM ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+
+				if (preg_match('/^SELECT/', $explain_query))
+				{
+					$html_table = false;
+
+					if ($result = @pg_query($this->db_connect_id, "EXPLAIN $explain_query"))
+					{
+						while ($row = @pg_fetch_assoc($result, null))
+						{
+							$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+						}
+					}
+					@pg_free_result($result);
+
+					if ($html_table)
+					{
+						$this->html_hold .= '</table>';
+					}
+				}
+
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @pg_query($this->db_connect_id, $query);
+				while ($void = @pg_fetch_assoc($result, null))
+				{
+					// Take the time spent on parsing rows into account
+				}
+				@pg_free_result($result);
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/sqlite.php b/phpBB/phpbb/db/driver/sqlite.php
new file mode 100644
index 0000000000..d5da0e2438
--- /dev/null
+++ b/phpBB/phpbb/db/driver/sqlite.php
@@ -0,0 +1,378 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* Sqlite Database Abstraction Layer
+* Minimum Requirement: 2.8.2+
+*/
+class sqlite extends \phpbb\db\driver\driver
+{
+	var $connect_error = '';
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		$this->persistency = $persistency;
+		$this->user = $sqluser;
+		$this->server = $sqlserver . (($port) ? ':' . $port : '');
+		$this->dbname = $database;
+
+		$error = '';
+		if ($this->persistency)
+		{
+			if (!function_exists('sqlite_popen'))
+			{
+				$this->connect_error = 'sqlite_popen function does not exist, is sqlite extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @sqlite_popen($this->server, 0666, $error);
+		}
+		else
+		{
+			if (!function_exists('sqlite_open'))
+			{
+				$this->connect_error = 'sqlite_open function does not exist, is sqlite extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @sqlite_open($this->server, 0666, $error);
+		}
+
+		if ($this->db_connect_id)
+		{
+			@sqlite_query('PRAGMA short_column_names = 1', $this->db_connect_id);
+//			@sqlite_query('PRAGMA encoding = "UTF-8"', $this->db_connect_id);
+		}
+
+		return ($this->db_connect_id) ? true : array('message' => $error);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('sqlite_version')) === false)
+		{
+			$result = @sqlite_query('SELECT sqlite_version() AS version', $this->db_connect_id);
+			$row = @sqlite_fetch_array($result, SQLITE_ASSOC);
+
+			$this->sql_server_version = (!empty($row['version'])) ? $row['version'] : 0;
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('sqlite_version', $this->sql_server_version);
+			}
+		}
+
+		return ($raw) ? $this->sql_server_version : 'SQLite ' . $this->sql_server_version;
+	}
+
+	/**
+	* SQL Transaction
+	* @access private
+	*/
+	function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return @sqlite_query('BEGIN', $this->db_connect_id);
+			break;
+
+			case 'commit':
+				return @sqlite_query('COMMIT', $this->db_connect_id);
+			break;
+
+			case 'rollback':
+				return @sqlite_query('ROLLBACK', $this->db_connect_id);
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @sqlite_query($query, $this->db_connect_id)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+				else if (strpos($query, 'SELECT') === 0 && $this->query_result)
+				{
+					$this->open_queries[(int) $this->query_result] = $this->query_result;
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* Build LIMIT query
+	*/
+	function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// if $total is set to 0 we do not want to limit the number of rows
+		if ($total == 0)
+		{
+			$total = -1;
+		}
+
+		$query .= "\n LIMIT " . ((!empty($offset)) ? $offset . ', ' . $total : $total);
+
+		return $this->sql_query($query, $cache_ttl);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_affectedrows()
+	{
+		return ($this->db_connect_id) ? @sqlite_changes($this->db_connect_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		return ($query_id !== false) ? @sqlite_fetch_array($query_id, SQLITE_ASSOC) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		return ($query_id !== false) ? @sqlite_seek($query_id, $rownum) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_nextid()
+	{
+		return ($this->db_connect_id) ? @sqlite_last_insert_rowid($this->db_connect_id) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	function sql_escape($msg)
+	{
+		return @sqlite_escape_string($msg);
+	}
+
+	/**
+	* {@inheritDoc}
+	*
+	* For SQLite an underscore is a not-known character... this may change with SQLite3
+	*/
+	function sql_like_expression($expression)
+	{
+		// Unlike LIKE, GLOB is unfortunately case sensitive.
+		// We only catch * and ? here, not the character map possible on file globbing.
+		$expression = str_replace(array(chr(0) . '_', chr(0) . '%'), array(chr(0) . '?', chr(0) . '*'), $expression);
+
+		$expression = str_replace(array('?', '*'), array("\?", "\*"), $expression);
+		$expression = str_replace(array(chr(0) . "\?", chr(0) . "\*"), array('?', '*'), $expression);
+
+		return 'GLOB \'' . $this->sql_escape($expression) . '\'';
+	}
+
+	/**
+	* {@inheritDoc}
+	*
+	* For SQLite an underscore is a not-known character...
+	*/
+	function sql_not_like_expression($expression)
+	{
+		// Unlike NOT LIKE, NOT GLOB is unfortunately case sensitive.
+		// We only catch * and ? here, not the character map possible on file globbing.
+		$expression = str_replace(array(chr(0) . '_', chr(0) . '%'), array(chr(0) . '?', chr(0) . '*'), $expression);
+
+		$expression = str_replace(array('?', '*'), array("\?", "\*"), $expression);
+		$expression = str_replace(array(chr(0) . "\?", chr(0) . "\*"), array('?', '*'), $expression);
+
+		return 'NOT GLOB \'' . $this->sql_escape($expression) . '\'';
+	}
+
+	/**
+	* return sql error array
+	* @access private
+	*/
+	function _sql_error()
+	{
+		if (function_exists('sqlite_error_string'))
+		{
+			$error = array(
+				'message'	=> @sqlite_error_string(@sqlite_last_error($this->db_connect_id)),
+				'code'		=> @sqlite_last_error($this->db_connect_id),
+			);
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Build db-specific query data
+	* @access private
+	*/
+	function _sql_custom_build($stage, $data)
+	{
+		return $data;
+	}
+
+	/**
+	* Close sql connection
+	* @access private
+	*/
+	function _sql_close()
+	{
+		return @sqlite_close($this->db_connect_id);
+	}
+
+	/**
+	* Build db-specific report
+	* @access private
+	*/
+	function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = @sqlite_query($query, $this->db_connect_id);
+				while ($void = @sqlite_fetch_array($result, SQLITE_ASSOC))
+				{
+					// Take the time spent on parsing rows into account
+				}
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}
diff --git a/phpBB/phpbb/db/driver/sqlite3.php b/phpBB/phpbb/db/driver/sqlite3.php
new file mode 100644
index 0000000000..cc3352af34
--- /dev/null
+++ b/phpBB/phpbb/db/driver/sqlite3.php
@@ -0,0 +1,405 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\db\driver;
+
+/**
+* SQLite3 Database Abstraction Layer
+* Minimum Requirement: 3.6.15+
+*/
+class sqlite3 extends \phpbb\db\driver\driver
+{
+	/**
+	* @var	string		Stores errors during connection setup in case the driver is not available
+	*/
+	protected $connect_error = '';
+
+	/**
+	* @var	\SQLite3	The SQLite3 database object to operate against
+	*/
+	protected $dbo = null;
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false, $new_link = false)
+	{
+		$this->persistency = false;
+		$this->user = $sqluser;
+		$this->server = $sqlserver . (($port) ? ':' . $port : '');
+		$this->dbname = $database;
+
+		if (!class_exists('SQLite3', false))
+		{
+			$this->connect_error = 'SQLite3 not found, is the extension installed?';
+			return $this->sql_error('');
+		}
+
+		try
+		{
+			$this->dbo = new \SQLite3($this->server, SQLITE3_OPEN_READWRITE | SQLITE3_OPEN_CREATE);
+			$this->dbo->busyTimeout(60000);
+			$this->db_connect_id = true;
+		}
+		catch (\Exception $e)
+		{
+			$this->connect_error = $e->getMessage();
+			return array('message' => $this->connect_error);
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_server_info($raw = false, $use_cache = true)
+	{
+		global $cache;
+
+		if (!$use_cache || empty($cache) || ($this->sql_server_version = $cache->get('sqlite_version')) === false)
+		{
+			$version = \SQLite3::version();
+
+			$this->sql_server_version = $version['versionString'];
+
+			if (!empty($cache) && $use_cache)
+			{
+				$cache->put('sqlite_version', $this->sql_server_version);
+			}
+		}
+
+		return ($raw) ? $this->sql_server_version : 'SQLite ' . $this->sql_server_version;
+	}
+
+	/**
+	* SQL Transaction
+	*
+	* @param	string	$status		Should be one of the following strings:
+	*								begin, commit, rollback
+	* @return	bool	Success/failure of the transaction query
+	*/
+	protected function _sql_transaction($status = 'begin')
+	{
+		switch ($status)
+		{
+			case 'begin':
+				return $this->dbo->exec('BEGIN IMMEDIATE');
+			break;
+
+			case 'commit':
+				return $this->dbo->exec('COMMIT');
+			break;
+
+			case 'rollback':
+				return $this->dbo->exec('ROLLBACK');
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_query($query = '', $cache_ttl = 0)
+	{
+		if ($query != '')
+		{
+			global $cache;
+
+			// EXPLAIN only in extra debug mode
+			if (defined('DEBUG'))
+			{
+				$this->sql_report('start', $query);
+			}
+			else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+			{
+				$this->curtime = microtime(true);
+			}
+
+			$this->last_query_text = $query;
+			$this->query_result = ($cache && $cache_ttl) ? $cache->sql_load($query) : false;
+			$this->sql_add_num_queries($this->query_result);
+
+			if ($this->query_result === false)
+			{
+				if (($this->query_result = @$this->dbo->query($query)) === false)
+				{
+					$this->sql_error($query);
+				}
+
+				if (defined('DEBUG'))
+				{
+					$this->sql_report('stop', $query);
+				}
+				else if (defined('PHPBB_DISPLAY_LOAD_TIME'))
+				{
+					$this->sql_time += microtime(true) - $this->curtime;
+				}
+
+				if ($cache && $cache_ttl)
+				{
+					$this->query_result = $cache->sql_save($this, $query, $this->query_result, $cache_ttl);
+				}
+			}
+			else if (defined('DEBUG'))
+			{
+				$this->sql_report('fromcache', $query);
+			}
+		}
+		else
+		{
+			return false;
+		}
+
+		return $this->query_result;
+	}
+
+	/**
+	* Build LIMIT query
+	*
+	* @param	string	$query		The SQL query to execute
+	* @param	int		$total		The number of rows to select
+	* @param	int		$offset
+	* @param	int		$cache_ttl	Either 0 to avoid caching or
+	*				the time in seconds which the result shall be kept in cache
+	* @return	mixed	Buffered, seekable result handle, false on error
+	*/
+	protected function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
+	{
+		$this->query_result = false;
+
+		// if $total is set to 0 we do not want to limit the number of rows
+		if ($total == 0)
+		{
+			$total = -1;
+		}
+
+		$query .= "\n LIMIT " . ((!empty($offset)) ? $offset . ', ' . $total : $total);
+
+		return $this->sql_query($query, $cache_ttl);
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_affectedrows()
+	{
+		return ($this->db_connect_id) ? $this->dbo->changes() : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_fetchrow($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_fetchrow($query_id);
+		}
+
+		return is_object($query_id) ? $query_id->fetchArray(SQLITE3_ASSOC) : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_nextid()
+	{
+		return ($this->db_connect_id) ? $this->dbo->lastInsertRowID() : false;
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_freeresult($query_id = false)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if ($cache && !is_object($query_id) && $cache->sql_exists($query_id))
+		{
+			return $cache->sql_freeresult($query_id);
+		}
+
+		if ($query_id)
+		{
+			return @$query_id->finalize();
+		}
+	}
+
+	/**
+	* {@inheritDoc}
+	*/
+	public function sql_escape($msg)
+	{
+		return \SQLite3::escapeString($msg);
+	}
+
+	/**
+	* {@inheritDoc}
+	*
+	* For SQLite an underscore is an unknown character.
+	*/
+	public function sql_like_expression($expression)
+	{
+		// Unlike LIKE, GLOB is unfortunately case sensitive.
+		// We only catch * and ? here, not the character map possible on file globbing.
+		$expression = str_replace(array(chr(0) . '_', chr(0) . '%'), array(chr(0) . '?', chr(0) . '*'), $expression);
+
+		$expression = str_replace(array('?', '*'), array("\?", "\*"), $expression);
+		$expression = str_replace(array(chr(0) . "\?", chr(0) . "\*"), array('?', '*'), $expression);
+
+		return 'GLOB \'' . $this->sql_escape($expression) . '\'';
+	}
+
+	/**
+	* {@inheritDoc}
+	*
+	* For SQLite an underscore is an unknown character.
+	*/
+	public function sql_not_like_expression($expression)
+	{
+		// Unlike NOT LIKE, NOT GLOB is unfortunately case sensitive
+		// We only catch * and ? here, not the character map possible on file globbing.
+		$expression = str_replace(array(chr(0) . '_', chr(0) . '%'), array(chr(0) . '?', chr(0) . '*'), $expression);
+
+		$expression = str_replace(array('?', '*'), array("\?", "\*"), $expression);
+		$expression = str_replace(array(chr(0) . "\?", chr(0) . "\*"), array('?', '*'), $expression);
+
+		return 'NOT GLOB \'' . $this->sql_escape($expression) . '\'';
+	}
+
+	/**
+	* return sql error array
+	*
+	* @return array
+	*/
+	protected function _sql_error()
+	{
+		if (class_exists('SQLite3', false) && isset($this->dbo))
+		{
+			$error = array(
+				'message'	=> $this->dbo->lastErrorMsg(),
+				'code'		=> $this->dbo->lastErrorCode(),
+			);
+		}
+		else
+		{
+			$error = array(
+				'message'	=> $this->connect_error,
+				'code'		=> '',
+			);
+		}
+
+		return $error;
+	}
+
+	/**
+	* Build db-specific query data
+	*
+	* @param	string	$stage		Available stages: FROM, WHERE
+	* @param	mixed	$data		A string containing the CROSS JOIN query or an array of WHERE clauses
+	*
+	* @return	string	The db-specific query fragment
+	*/
+	protected function _sql_custom_build($stage, $data)
+	{
+		return $data;
+	}
+
+	/**
+	* Close sql connection
+	*
+	* @return	bool		False if failure
+	*/
+	protected function _sql_close()
+	{
+		return $this->dbo->close();
+	}
+
+	/**
+	* Build db-specific report
+	*
+	* @param	string	$mode		Available modes: display, start, stop,
+	*								add_select_row, fromcache, record_fromcache
+	* @param	string	$query		The Query that should be explained
+	* @return	mixed		Either a full HTML page, boolean or null
+	*/
+	protected function _sql_report($mode, $query = '')
+	{
+		switch ($mode)
+		{
+			case 'start':
+
+				$explain_query = $query;
+				if (preg_match('/UPDATE ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+				else if (preg_match('/DELETE FROM ([a-z0-9_]+).*?WHERE(.*)/s', $query, $m))
+				{
+					$explain_query = 'SELECT * FROM ' . $m[1] . ' WHERE ' . $m[2];
+				}
+
+				if (preg_match('/^SELECT/', $explain_query))
+				{
+					$html_table = false;
+
+					if ($result = $this->dbo->query("EXPLAIN QUERY PLAN $explain_query"))
+					{
+						while ($row = $result->fetchArray(SQLITE3_ASSOC))
+						{
+							$html_table = $this->sql_report('add_select_row', $query, $html_table, $row);
+						}
+					}
+
+					if ($html_table)
+					{
+						$this->html_hold .= '</table>';
+					}
+				}
+
+			break;
+
+			case 'fromcache':
+				$endtime = explode(' ', microtime());
+				$endtime = $endtime[0] + $endtime[1];
+
+				$result = $this->dbo->query($query);
+				while ($void = $result->fetchArray(SQLITE3_ASSOC))
+				{
+					// Take the time spent on parsing rows into account
+				}
+
+				$splittime = explode(' ', microtime());
+				$splittime = $splittime[0] + $splittime[1];
+
+				$this->sql_report('record_fromcache', $query, $endtime, $splittime);
+
+			break;
+		}
+	}
+}