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diff --git a/phpBB/phpbb/db/tools/mssql.php b/phpBB/phpbb/db/tools/mssql.php
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+++ b/phpBB/phpbb/db/tools/mssql.php
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+<?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\tools;
+
+/**
+ * Database Tools for handling cross-db actions such as altering columns, etc.
+ * Currently not supported is returning SQL for creating tables.
+ */
+class mssql extends tools
+{
+	/**
+	 * Is the used MS SQL Server a SQL Server 2000?
+	 * @var bool
+	 */
+	protected $is_sql_server_2000;
+
+	/**
+	 * Get the column types for mssql based databases
+	 *
+	 * @return array
+	 */
+	public static function get_dbms_type_map()
+	{
+		return array(
+			'mssql'		=> array(
+				'INT:'		=> '[int]',
+				'BINT'		=> '[float]',
+				'UINT'		=> '[int]',
+				'UINT:'		=> '[int]',
+				'TINT:'		=> '[int]',
+				'USINT'		=> '[int]',
+				'BOOL'		=> '[int]',
+				'VCHAR'		=> '[varchar] (255)',
+				'VCHAR:'	=> '[varchar] (%d)',
+				'CHAR:'		=> '[char] (%d)',
+				'XSTEXT'	=> '[varchar] (1000)',
+				'STEXT'		=> '[varchar] (3000)',
+				'TEXT'		=> '[varchar] (8000)',
+				'MTEXT'		=> '[text]',
+				'XSTEXT_UNI'=> '[varchar] (100)',
+				'STEXT_UNI'	=> '[varchar] (255)',
+				'TEXT_UNI'	=> '[varchar] (4000)',
+				'MTEXT_UNI'	=> '[text]',
+				'TIMESTAMP'	=> '[int]',
+				'DECIMAL'	=> '[float]',
+				'DECIMAL:'	=> '[float]',
+				'PDECIMAL'	=> '[float]',
+				'PDECIMAL:'	=> '[float]',
+				'VCHAR_UNI'	=> '[varchar] (255)',
+				'VCHAR_UNI:'=> '[varchar] (%d)',
+				'VCHAR_CI'	=> '[varchar] (255)',
+				'VARBINARY'	=> '[varchar] (255)',
+			),
+
+			'mssqlnative'	=> array(
+				'INT:'		=> '[int]',
+				'BINT'		=> '[float]',
+				'UINT'		=> '[int]',
+				'UINT:'		=> '[int]',
+				'TINT:'		=> '[int]',
+				'USINT'		=> '[int]',
+				'BOOL'		=> '[int]',
+				'VCHAR'		=> '[varchar] (255)',
+				'VCHAR:'	=> '[varchar] (%d)',
+				'CHAR:'		=> '[char] (%d)',
+				'XSTEXT'	=> '[varchar] (1000)',
+				'STEXT'		=> '[varchar] (3000)',
+				'TEXT'		=> '[varchar] (8000)',
+				'MTEXT'		=> '[text]',
+				'XSTEXT_UNI'=> '[varchar] (100)',
+				'STEXT_UNI'	=> '[varchar] (255)',
+				'TEXT_UNI'	=> '[varchar] (4000)',
+				'MTEXT_UNI'	=> '[text]',
+				'TIMESTAMP'	=> '[int]',
+				'DECIMAL'	=> '[float]',
+				'DECIMAL:'	=> '[float]',
+				'PDECIMAL'	=> '[float]',
+				'PDECIMAL:'	=> '[float]',
+				'VCHAR_UNI'	=> '[varchar] (255)',
+				'VCHAR_UNI:'=> '[varchar] (%d)',
+				'VCHAR_CI'	=> '[varchar] (255)',
+				'VARBINARY'	=> '[varchar] (255)',
+			),
+		);
+	}
+
+	/**
+	* Constructor. Set DB Object and set {@link $return_statements return_statements}.
+	*
+	* @param \phpbb\db\driver\driver_interface	$db					Database connection
+	* @param bool		$return_statements	True if only statements should be returned and no SQL being executed
+	*/
+	public function __construct(\phpbb\db\driver\driver_interface $db, $return_statements = false)
+	{
+		parent::__construct($db, $return_statements);
+
+		// Determine mapping database type
+		switch ($this->db->get_sql_layer())
+		{
+			case 'mssql':
+			case 'mssql_odbc':
+				$this->sql_layer = 'mssql';
+			break;
+
+			case 'mssqlnative':
+				$this->sql_layer = 'mssqlnative';
+			break;
+		}
+
+		$this->dbms_type_map = self::get_dbms_type_map();
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_list_tables()
+	{
+		$sql = "SELECT name
+			FROM sysobjects
+			WHERE type='U'";
+		$result = $this->db->sql_query($sql);
+
+		$tables = array();
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$name = current($row);
+			$tables[$name] = $name;
+		}
+		$this->db->sql_freeresult($result);
+
+		return $tables;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_create_table($table_name, $table_data)
+	{
+		// holds the DDL for a column
+		$columns = $statements = array();
+
+		if ($this->sql_table_exists($table_name))
+		{
+			return $this->_sql_run_sql($statements);
+		}
+
+		// Begin transaction
+		$statements[] = 'begin';
+
+		// Determine if we have created a PRIMARY KEY in the earliest
+		$primary_key_gen = false;
+
+		// Determine if the table requires a sequence
+		$create_sequence = false;
+
+		// Begin table sql statement
+		$table_sql = 'CREATE TABLE [' . $table_name . '] (' . "\n";
+
+		if (!isset($table_data['PRIMARY_KEY']))
+		{
+			$table_data['COLUMNS']['mssqlindex'] = array('UINT', null, 'auto_increment');
+			$table_data['PRIMARY_KEY'] = 'mssqlindex';
+		}
+
+		// Iterate through the columns to create a table
+		foreach ($table_data['COLUMNS'] as $column_name => $column_data)
+		{
+			// here lies an array, filled with information compiled on the column's data
+			$prepared_column = $this->sql_prepare_column_data($table_name, $column_name, $column_data);
+
+			if (isset($prepared_column['auto_increment']) && $prepared_column['auto_increment'] && strlen($column_name) > 26) // "${column_name}_gen"
+			{
+				trigger_error("Index name '${column_name}_gen' on table '$table_name' is too long. The maximum auto increment column length is 26 characters.", E_USER_ERROR);
+			}
+
+			// here we add the definition of the new column to the list of columns
+			$columns[] = "\t [{$column_name}] " . $prepared_column['column_type_sql_default'];
+
+			// see if we have found a primary key set due to a column definition if we have found it, we can stop looking
+			if (!$primary_key_gen)
+			{
+				$primary_key_gen = isset($prepared_column['primary_key_set']) && $prepared_column['primary_key_set'];
+			}
+
+			// create sequence DDL based off of the existance of auto incrementing columns
+			if (!$create_sequence && isset($prepared_column['auto_increment']) && $prepared_column['auto_increment'])
+			{
+				$create_sequence = $column_name;
+			}
+		}
+
+		// this makes up all the columns in the create table statement
+		$table_sql .= implode(",\n", $columns);
+
+		// Close the table for two DBMS and add to the statements
+		$table_sql .= "\n);";
+		$statements[] = $table_sql;
+
+		// we have yet to create a primary key for this table,
+		// this means that we can add the one we really wanted instead
+		if (!$primary_key_gen)
+		{
+			// Write primary key
+			if (isset($table_data['PRIMARY_KEY']))
+			{
+				if (!is_array($table_data['PRIMARY_KEY']))
+				{
+					$table_data['PRIMARY_KEY'] = array($table_data['PRIMARY_KEY']);
+				}
+
+				// We need the data here
+				$old_return_statements = $this->return_statements;
+				$this->return_statements = true;
+
+				$primary_key_stmts = $this->sql_create_primary_key($table_name, $table_data['PRIMARY_KEY']);
+				foreach ($primary_key_stmts as $pk_stmt)
+				{
+					$statements[] = $pk_stmt;
+				}
+
+				$this->return_statements = $old_return_statements;
+			}
+		}
+
+		// Write Keys
+		if (isset($table_data['KEYS']))
+		{
+			foreach ($table_data['KEYS'] as $key_name => $key_data)
+			{
+				if (!is_array($key_data[1]))
+				{
+					$key_data[1] = array($key_data[1]);
+				}
+
+				$old_return_statements = $this->return_statements;
+				$this->return_statements = true;
+
+				$key_stmts = ($key_data[0] == 'UNIQUE') ? $this->sql_create_unique_index($table_name, $key_name, $key_data[1]) : $this->sql_create_index($table_name, $key_name, $key_data[1]);
+
+				foreach ($key_stmts as $key_stmt)
+				{
+					$statements[] = $key_stmt;
+				}
+
+				$this->return_statements = $old_return_statements;
+			}
+		}
+
+		// Commit Transaction
+		$statements[] = 'commit';
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_list_columns($table_name)
+	{
+		$columns = array();
+
+		$sql = "SELECT c.name
+			FROM syscolumns c
+			LEFT JOIN sysobjects o ON c.id = o.id
+			WHERE o.name = '{$table_name}'";
+		$result = $this->db->sql_query($sql);
+
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$column = strtolower(current($row));
+			$columns[$column] = $column;
+		}
+		$this->db->sql_freeresult($result);
+
+		return $columns;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_index_exists($table_name, $index_name)
+	{
+		$sql = "EXEC sp_statistics '$table_name'";
+		$result = $this->db->sql_query($sql);
+
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			if ($row['TYPE'] == 3)
+			{
+				if (strtolower($row['INDEX_NAME']) == strtolower($index_name))
+				{
+					$this->db->sql_freeresult($result);
+					return true;
+				}
+			}
+		}
+		$this->db->sql_freeresult($result);
+
+		return false;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_unique_index_exists($table_name, $index_name)
+	{
+		$sql = "EXEC sp_statistics '$table_name'";
+		$result = $this->db->sql_query($sql);
+
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			// Usually NON_UNIQUE is the column we want to check, but we allow for both
+			if ($row['TYPE'] == 3)
+			{
+				if (strtolower($row['INDEX_NAME']) == strtolower($index_name))
+				{
+					$this->db->sql_freeresult($result);
+					return true;
+				}
+			}
+		}
+		$this->db->sql_freeresult($result);
+
+		return false;
+	}
+
+	/**
+	 * {@inheritDoc}
+	*/
+	function sql_prepare_column_data($table_name, $column_name, $column_data)
+	{
+		if (strlen($column_name) > 30)
+		{
+			trigger_error("Column name '$column_name' on table '$table_name' is too long. The maximum is 30 characters.", E_USER_ERROR);
+		}
+
+		// Get type
+		list($column_type, ) = $this->get_column_type($column_data[0]);
+
+		// Adjust default value if db-dependent specified
+		if (is_array($column_data[1]))
+		{
+			$column_data[1] = (isset($column_data[1][$this->sql_layer])) ? $column_data[1][$this->sql_layer] : $column_data[1]['default'];
+		}
+
+		$sql = '';
+
+		$return_array = array();
+
+		$sql .= " {$column_type} ";
+		$sql_default = " {$column_type} ";
+
+		// For adding columns we need the default definition
+		if (!is_null($column_data[1]))
+		{
+			// For hexadecimal values do not use single quotes
+			if (strpos($column_data[1], '0x') === 0)
+			{
+				$return_array['default'] = 'DEFAULT (' . $column_data[1] . ') ';
+				$sql_default .= $return_array['default'];
+			}
+			else
+			{
+				$return_array['default'] = 'DEFAULT (' . ((is_numeric($column_data[1])) ? $column_data[1] : "'{$column_data[1]}'") . ') ';
+				$sql_default .= $return_array['default'];
+			}
+		}
+
+		if (isset($column_data[2]) && $column_data[2] == 'auto_increment')
+		{
+			// $sql .= 'IDENTITY (1, 1) ';
+			$sql_default .= 'IDENTITY (1, 1) ';
+		}
+
+		$return_array['textimage'] = $column_type === '[text]';
+
+		if (!is_null($column_data[1]) || (isset($column_data[2]) && $column_data[2] == 'auto_increment'))
+		{
+			$sql .= 'NOT NULL';
+			$sql_default .= 'NOT NULL';
+		}
+		else
+		{
+			$sql .= 'NULL';
+			$sql_default .= 'NULL';
+		}
+
+		$return_array['column_type_sql_default'] = $sql_default;
+
+		$return_array['column_type_sql'] = $sql;
+
+		return $return_array;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_column_add($table_name, $column_name, $column_data, $inline = false)
+	{
+		$column_data = $this->sql_prepare_column_data($table_name, $column_name, $column_data);
+		$statements = array();
+
+		// Does not support AFTER, only through temporary table
+		$statements[] = 'ALTER TABLE [' . $table_name . '] ADD [' . $column_name . '] ' . $column_data['column_type_sql_default'];
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_column_remove($table_name, $column_name, $inline = false)
+	{
+		$statements = array();
+
+		// We need the data here
+		$old_return_statements = $this->return_statements;
+		$this->return_statements = true;
+
+		$indexes = $this->get_existing_indexes($table_name, $column_name);
+		$indexes = array_merge($indexes, $this->get_existing_indexes($table_name, $column_name, true));
+
+		// Drop any indexes
+		$recreate_indexes = array();
+		if (!empty($indexes))
+		{
+			foreach ($indexes as $index_name => $index_data)
+			{
+				$result = $this->sql_index_drop($table_name, $index_name);
+				$statements = array_merge($statements, $result);
+				if (sizeof($index_data) > 1)
+				{
+					// Remove this column from the index and recreate it
+					$recreate_indexes[$index_name] = array_diff($index_data, array($column_name));
+				}
+			}
+		}
+
+		// Drop default value constraint
+		$result = $this->mssql_get_drop_default_constraints_queries($table_name, $column_name);
+		$statements = array_merge($statements, $result);
+
+		// Remove the column
+		$statements[] = 'ALTER TABLE [' . $table_name . '] DROP COLUMN [' . $column_name . ']';
+
+		if (!empty($recreate_indexes))
+		{
+			// Recreate indexes after we removed the column
+			foreach ($recreate_indexes as $index_name => $index_data)
+			{
+				$result = $this->sql_create_index($table_name, $index_name, $index_data);
+				$statements = array_merge($statements, $result);
+			}
+		}
+
+		$this->return_statements = $old_return_statements;
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_index_drop($table_name, $index_name)
+	{
+		$statements = array();
+
+		$statements[] = 'DROP INDEX ' . $table_name . '.' . $index_name;
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_table_drop($table_name)
+	{
+		$statements = array();
+
+		if (!$this->sql_table_exists($table_name))
+		{
+			return $this->_sql_run_sql($statements);
+		}
+
+		// the most basic operation, get rid of the table
+		$statements[] = 'DROP TABLE ' . $table_name;
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_create_primary_key($table_name, $column, $inline = false)
+	{
+		$statements = array();
+
+		$sql = "ALTER TABLE [{$table_name}] WITH NOCHECK ADD ";
+		$sql .= "CONSTRAINT [PK_{$table_name}] PRIMARY KEY  CLUSTERED (";
+		$sql .= '[' . implode("],\n\t\t[", $column) . ']';
+		$sql .= ')';
+
+		$statements[] = $sql;
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_create_unique_index($table_name, $index_name, $column)
+	{
+		$statements = array();
+
+		$this->check_index_name_length($table_name, $index_name);
+
+		$statements[] = 'CREATE UNIQUE INDEX [' . $index_name . '] ON [' . $table_name . ']([' . implode('], [', $column) . '])';
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_create_index($table_name, $index_name, $column)
+	{
+		$statements = array();
+
+		$this->check_index_name_length($table_name, $index_name);
+
+		// remove index length
+		$column = preg_replace('#:.*$#', '', $column);
+
+		$statements[] = 'CREATE INDEX [' . $index_name . '] ON [' . $table_name . ']([' . implode('], [', $column) . '])';
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_list_index($table_name)
+	{
+		$index_array = array();
+		$sql = "EXEC sp_statistics '$table_name'";
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			if ($row['TYPE'] == 3)
+			{
+				$index_array[] = strtolower($row['INDEX_NAME']);
+			}
+		}
+		$this->db->sql_freeresult($result);
+
+		return $index_array;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	function sql_column_change($table_name, $column_name, $column_data, $inline = false)
+	{
+		$column_data = $this->sql_prepare_column_data($table_name, $column_name, $column_data);
+		$statements = array();
+
+		// We need the data here
+		$old_return_statements = $this->return_statements;
+		$this->return_statements = true;
+
+		$indexes = $this->get_existing_indexes($table_name, $column_name);
+		$unique_indexes = $this->get_existing_indexes($table_name, $column_name, true);
+
+		// Drop any indexes
+		if (!empty($indexes) || !empty($unique_indexes))
+		{
+			$drop_indexes = array_merge(array_keys($indexes), array_keys($unique_indexes));
+			foreach ($drop_indexes as $index_name)
+			{
+				$result = $this->sql_index_drop($table_name, $index_name);
+				$statements = array_merge($statements, $result);
+			}
+		}
+
+		// Drop default value constraint
+		$result = $this->mssql_get_drop_default_constraints_queries($table_name, $column_name);
+		$statements = array_merge($statements, $result);
+
+		// Change the column
+		$statements[] = 'ALTER TABLE [' . $table_name . '] ALTER COLUMN [' . $column_name . '] ' . $column_data['column_type_sql'];
+
+		if (!empty($column_data['default']))
+		{
+			// Add new default value constraint
+			$statements[] = 'ALTER TABLE [' . $table_name . '] ADD CONSTRAINT [DF_' . $table_name . '_' . $column_name . '_1] ' . $this->db->sql_escape($column_data['default']) . ' FOR [' . $column_name . ']';
+		}
+
+		if (!empty($indexes))
+		{
+			// Recreate indexes after we changed the column
+			foreach ($indexes as $index_name => $index_data)
+			{
+				$result = $this->sql_create_index($table_name, $index_name, $index_data);
+				$statements = array_merge($statements, $result);
+			}
+		}
+
+		if (!empty($unique_indexes))
+		{
+			// Recreate unique indexes after we changed the column
+			foreach ($unique_indexes as $index_name => $index_data)
+			{
+				$result = $this->sql_create_unique_index($table_name, $index_name, $index_data);
+				$statements = array_merge($statements, $result);
+			}
+		}
+
+		$this->return_statements = $old_return_statements;
+
+		return $this->_sql_run_sql($statements);
+	}
+
+	/**
+	* Get queries to drop the default constraints of a column
+	*
+	* We need to drop the default constraints of a column,
+	* before being able to change their type or deleting them.
+	*
+	* @param string $table_name
+	* @param string $column_name
+	* @return array		Array with SQL statements
+	*/
+	protected function mssql_get_drop_default_constraints_queries($table_name, $column_name)
+	{
+		$statements = array();
+		if ($this->mssql_is_sql_server_2000())
+		{
+			// http://msdn.microsoft.com/en-us/library/aa175912%28v=sql.80%29.aspx
+			// Deprecated in SQL Server 2005
+			$sql = "SELECT so.name AS def_name
+				FROM sysobjects so
+				JOIN sysconstraints sc ON so.id = sc.constid
+				WHERE object_name(so.parent_obj) = '{$table_name}'
+					AND so.xtype = 'D'
+					AND sc.colid = (SELECT colid FROM syscolumns
+						WHERE id = object_id('{$table_name}')
+							AND name = '{$column_name}')";
+		}
+		else
+		{
+			$sql = "SELECT dobj.name AS def_name
+				FROM sys.columns col
+					LEFT OUTER JOIN sys.objects dobj ON (dobj.object_id = col.default_object_id AND dobj.type = 'D')
+				WHERE col.object_id = object_id('{$table_name}')
+					AND col.name = '{$column_name}'
+					AND dobj.name IS NOT NULL";
+		}
+
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$statements[] = 'ALTER TABLE [' . $table_name . '] DROP CONSTRAINT [' . $row['def_name'] . ']';
+		}
+		$this->db->sql_freeresult($result);
+
+		return $statements;
+	}
+
+	/**
+	* Get a list with existing indexes for the column
+	*
+	* @param string $table_name
+	* @param string $column_name
+	* @param bool $unique Should we get unique indexes or normal ones
+	* @return array		Array with Index name => columns
+	*/
+	public function get_existing_indexes($table_name, $column_name, $unique = false)
+	{
+		$existing_indexes = array();
+		if ($this->mssql_is_sql_server_2000())
+		{
+			// http://msdn.microsoft.com/en-us/library/aa175912%28v=sql.80%29.aspx
+			// Deprecated in SQL Server 2005
+			$sql = "SELECT DISTINCT ix.name AS phpbb_index_name
+				FROM sysindexes ix
+				INNER JOIN sysindexkeys ixc
+					ON ixc.id = ix.id
+						AND ixc.indid = ix.indid
+				INNER JOIN syscolumns cols
+					ON cols.colid = ixc.colid
+						AND cols.id = ix.id
+				WHERE ix.id = object_id('{$table_name}')
+					AND cols.name = '{$column_name}'
+					AND INDEXPROPERTY(ix.id, ix.name, 'IsUnique') = " . ($unique ? '1' : '0');
+		}
+		else
+		{
+			$sql = "SELECT DISTINCT ix.name AS phpbb_index_name
+				FROM sys.indexes ix
+				INNER JOIN sys.index_columns ixc
+					ON ixc.object_id = ix.object_id
+						AND ixc.index_id = ix.index_id
+				INNER JOIN sys.columns cols
+					ON cols.column_id = ixc.column_id
+						AND cols.object_id = ix.object_id
+				WHERE ix.object_id = object_id('{$table_name}')
+					AND cols.name = '{$column_name}'
+					AND ix.is_unique = " . ($unique ? '1' : '0');
+		}
+
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			if (!isset($row['is_unique']) || ($unique && $row['is_unique'] == 'UNIQUE') || (!$unique && $row['is_unique'] == 'NONUNIQUE'))
+			{
+				$existing_indexes[$row['phpbb_index_name']] = array();
+			}
+		}
+		$this->db->sql_freeresult($result);
+
+		if (empty($existing_indexes))
+		{
+			return array();
+		}
+
+		if ($this->mssql_is_sql_server_2000())
+		{
+			$sql = "SELECT DISTINCT ix.name AS phpbb_index_name, cols.name AS phpbb_column_name
+				FROM sysindexes ix
+				INNER JOIN sysindexkeys ixc
+					ON ixc.id = ix.id
+						AND ixc.indid = ix.indid
+				INNER JOIN syscolumns cols
+					ON cols.colid = ixc.colid
+						AND cols.id = ix.id
+				WHERE ix.id = object_id('{$table_name}')
+					AND " . $this->db->sql_in_set('ix.name', array_keys($existing_indexes));
+		}
+		else
+		{
+			$sql = "SELECT DISTINCT ix.name AS phpbb_index_name, cols.name AS phpbb_column_name
+				FROM sys.indexes ix
+				INNER JOIN sys.index_columns ixc
+					ON ixc.object_id = ix.object_id
+						AND ixc.index_id = ix.index_id
+				INNER JOIN sys.columns cols
+					ON cols.column_id = ixc.column_id
+						AND cols.object_id = ix.object_id
+				WHERE ix.object_id = object_id('{$table_name}')
+					AND " . $this->db->sql_in_set('ix.name', array_keys($existing_indexes));
+		}
+
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$existing_indexes[$row['phpbb_index_name']][] = $row['phpbb_column_name'];
+		}
+		$this->db->sql_freeresult($result);
+
+		return $existing_indexes;
+	}
+
+	/**
+	* Is the used MS SQL Server a SQL Server 2000?
+	*
+	* @return bool
+	*/
+	protected function mssql_is_sql_server_2000()
+	{
+		if ($this->is_sql_server_2000 === null)
+		{
+			$sql = "SELECT CAST(SERVERPROPERTY('productversion') AS VARCHAR(25)) AS mssql_version";
+			$result = $this->db->sql_query($sql);
+			$properties = $this->db->sql_fetchrow($result);
+			$this->db->sql_freeresult($result);
+			$this->is_sql_server_2000 = $properties['mssql_version'][0] == '8';
+		}
+
+		return $this->is_sql_server_2000;
+	}
+
+}