Subversion Repositories SmartDukaan

<?php

/**

 * MySQL layer for DBO

 *

 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)

 * Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)

 *

 * Licensed under The MIT License

 * For full copyright and license information, please see the LICENSE.txt

 * Redistributions of files must retain the above copyright notice.

 *

 * @copyright     Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)

 * @link          http://cakephp.org CakePHP(tm) Project

 * @package       Cake.Model.Datasource.Database

 * @since         CakePHP(tm) v 0.10.5.1790

 * @license       http://www.opensource.org/licenses/mit-license.php MIT License

 */

App::uses('DboSource', 'Model/Datasource');

/**

 * MySQL DBO driver object

 *

 * Provides connection and SQL generation for MySQL RDMS

 *

 * @package       Cake.Model.Datasource.Database

 */

class Mysql extends DboSource {

/**

 * Datasource description

 *

 * @var string

 */

	public $description = "MySQL DBO Driver";

/**

 * Base configuration settings for MySQL driver

 *

 * @var array

 */

	protected $_baseConfig = array(

		'persistent' => true,

		'host' => 'localhost',

		'login' => 'root',

		'password' => '',

		'database' => 'cake',

		'port' => '3306',

		'flags' => array()

	);

/**

 * Reference to the PDO object connection

 *

 * @var PDO

 */

	protected $_connection = null;

/**

 * Start quote

 *

 * @var string

 */

	public $startQuote = "`";

/**

 * End quote

 *

 * @var string

 */

	public $endQuote = "`";

/**

 * use alias for update and delete. Set to true if version >= 4.1

 *

 * @var bool

 */

	protected $_useAlias = true;

/**

 * List of engine specific additional field parameters used on table creating

 *

 * @var array

 */

	public $fieldParameters = array(

		'charset' => array('value' => 'CHARACTER SET', 'quote' => false, 'join' => ' ', 'column' => false, 'position' => 'beforeDefault'),

		'collate' => array('value' => 'COLLATE', 'quote' => false, 'join' => ' ', 'column' => 'Collation', 'position' => 'beforeDefault'),

		'comment' => array('value' => 'COMMENT', 'quote' => true, 'join' => ' ', 'column' => 'Comment', 'position' => 'afterDefault'),

		'unsigned' => array(

			'value' => 'UNSIGNED', 'quote' => false, 'join' => ' ', 'column' => false, 'position' => 'beforeDefault',

			'noVal' => true,

			'options' => array(true),

			'types' => array('integer', 'float', 'decimal', 'biginteger')

		)

	);

/**

 * List of table engine specific parameters used on table creating

 *

 * @var array

 */

	public $tableParameters = array(

		'charset' => array('value' => 'DEFAULT CHARSET', 'quote' => false, 'join' => '=', 'column' => 'charset'),

		'collate' => array('value' => 'COLLATE', 'quote' => false, 'join' => '=', 'column' => 'Collation'),

		'engine' => array('value' => 'ENGINE', 'quote' => false, 'join' => '=', 'column' => 'Engine'),

		'comment' => array('value' => 'COMMENT', 'quote' => true, 'join' => '=', 'column' => 'Comment'),

	);

/**

 * MySQL column definition

 *

 * @var array

 */

	public $columns = array(

		'primary_key' => array('name' => 'NOT NULL AUTO_INCREMENT'),

		'string' => array('name' => 'varchar', 'limit' => '255'),

		'text' => array('name' => 'text'),

		'biginteger' => array('name' => 'bigint', 'limit' => '20'),

		'integer' => array('name' => 'int', 'limit' => '11', 'formatter' => 'intval'),

		'float' => array('name' => 'float', 'formatter' => 'floatval'),

		'decimal' => array('name' => 'decimal', 'formatter' => 'floatval'),

		'datetime' => array('name' => 'datetime', 'format' => 'Y-m-d H:i:s', 'formatter' => 'date'),

		'timestamp' => array('name' => 'timestamp', 'format' => 'Y-m-d H:i:s', 'formatter' => 'date'),

		'time' => array('name' => 'time', 'format' => 'H:i:s', 'formatter' => 'date'),

		'date' => array('name' => 'date', 'format' => 'Y-m-d', 'formatter' => 'date'),

		'binary' => array('name' => 'blob'),

		'boolean' => array('name' => 'tinyint', 'limit' => '1')

	);

/**

 * Mapping of collation names to character set names

 *

 * @var array

 */

	protected $_charsets = array();

/**

 * Connects to the database using options in the given configuration array.

 *

 * MySQL supports a few additional options that other drivers do not:

 *

 * - `unix_socket` Set to the path of the MySQL sock file. Can be used in place

 *   of host + port.

 * - `ssl_key` SSL key file for connecting via SSL. Must be combined with `ssl_cert`.

 * - `ssl_cert` The SSL certificate to use when connecting via SSL. Must be

 *   combined with `ssl_key`.

 * - `ssl_ca` The certificate authority for SSL connections.

 *

 * @return bool True if the database could be connected, else false

 * @throws MissingConnectionException

 */

	public function connect() {

		$config = $this->config;

		$this->connected = false;

		$flags = $config['flags'] + array(

			PDO::ATTR_PERSISTENT => $config['persistent'],

			PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true,

			PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION

		);

		if (!empty($config['encoding'])) {

			$flags[PDO::MYSQL_ATTR_INIT_COMMAND] = 'SET NAMES ' . $config['encoding'];

		}

		if (!empty($config['ssl_key']) && !empty($config['ssl_cert'])) {

			$flags[PDO::MYSQL_ATTR_SSL_KEY] = $config['ssl_key'];

			$flags[PDO::MYSQL_ATTR_SSL_CERT] = $config['ssl_cert'];

		}

		if (!empty($config['ssl_ca'])) {

			$flags[PDO::MYSQL_ATTR_SSL_CA] = $config['ssl_ca'];

		}

		if (empty($config['unix_socket'])) {

			$dsn = "mysql:host={$config['host']};port={$config['port']};dbname={$config['database']}";

		} else {

			$dsn = "mysql:unix_socket={$config['unix_socket']};dbname={$config['database']}";

		}

		try {

			$this->_connection = new PDO(

				$dsn,

				$config['login'],

				$config['password'],

				$flags

			);

			$this->connected = true;

			if (!empty($config['settings'])) {

				foreach ($config['settings'] as $key => $value) {

					$this->_execute("SET $key=$value");

				}

			}

		} catch (PDOException $e) {

			throw new MissingConnectionException(array(

				'class' => get_class($this),

				'message' => $e->getMessage()

			));

		}

		$this->_charsets = array();

		$this->_useAlias = (bool)version_compare($this->getVersion(), "4.1", ">=");

		return $this->connected;

	}

/**

 * Check whether the MySQL extension is installed/loaded

 *

 * @return bool

 */

	public function enabled() {

		return in_array('mysql', PDO::getAvailableDrivers());

	}

/**

 * Returns an array of sources (tables) in the database.

 *

 * @param mixed $data List of tables.

 * @return array Array of table names in the database

 */

	public function listSources($data = null) {

		$cache = parent::listSources();

		if ($cache) {

			return $cache;

		}

		$result = $this->_execute('SHOW TABLES FROM ' . $this->name($this->config['database']));

		if (!$result) {

			$result->closeCursor();

			return array();

		}

		$tables = array();

		while ($line = $result->fetch(PDO::FETCH_NUM)) {

			$tables[] = $line[0];

		}

		$result->closeCursor();

		parent::listSources($tables);

		return $tables;

	}

/**

 * Builds a map of the columns contained in a result

 *

 * @param PDOStatement $results The results to format.

 * @return void

 */

	public function resultSet($results) {

		$this->map = array();

		$numFields = $results->columnCount();

		$index = 0;

		while ($numFields-- > 0) {

			$column = $results->getColumnMeta($index);

			if ($column['len'] === 1 && (empty($column['native_type']) || $column['native_type'] === 'TINY')) {

				$type = 'boolean';

			} else {

				$type = empty($column['native_type']) ? 'string' : $column['native_type'];

			}

			if (!empty($column['table']) && strpos($column['name'], $this->virtualFieldSeparator) === false) {

				$this->map[$index++] = array($column['table'], $column['name'], $type);

			} else {

				$this->map[$index++] = array(0, $column['name'], $type);

			}

		}

	}

/**

 * Fetches the next row from the current result set

 *

 * @return mixed array with results fetched and mapped to column names or false if there is no results left to fetch

 */

	public function fetchResult() {

		if ($row = $this->_result->fetch(PDO::FETCH_NUM)) {

			$resultRow = array();

			foreach ($this->map as $col => $meta) {

				list($table, $column, $type) = $meta;

				$resultRow[$table][$column] = $row[$col];

				if ($type === 'boolean' && $row[$col] !== null) {

					$resultRow[$table][$column] = $this->boolean($resultRow[$table][$column]);

				}

			}

			return $resultRow;

		}

		$this->_result->closeCursor();

		return false;

	}

/**

 * Gets the database encoding

 *

 * @return string The database encoding

 */

	public function getEncoding() {

		return $this->_execute('SHOW VARIABLES LIKE ?', array('character_set_client'))->fetchObject()->Value;

	}

/**

 * Query charset by collation

 *

 * @param string $name Collation name

 * @return string Character set name

 */

	public function getCharsetName($name) {

		if ((bool)version_compare($this->getVersion(), "5", "<")) {

			return false;

		}

		if (isset($this->_charsets[$name])) {

			return $this->_charsets[$name];

		}

		$r = $this->_execute(

			'SELECT CHARACTER_SET_NAME FROM INFORMATION_SCHEMA.COLLATIONS WHERE COLLATION_NAME = ?',

			array($name)

		);

		$cols = $r->fetch(PDO::FETCH_ASSOC);

		if (isset($cols['CHARACTER_SET_NAME'])) {

			$this->_charsets[$name] = $cols['CHARACTER_SET_NAME'];

		} else {

			$this->_charsets[$name] = false;

		}

		return $this->_charsets[$name];

	}

/**

 * Returns an array of the fields in given table name.

 *

 * @param Model|string $model Name of database table to inspect or model instance

 * @return array Fields in table. Keys are name and type

 * @throws CakeException

 */

	public function describe($model) {

		$key = $this->fullTableName($model, false);

		$cache = parent::describe($key);

		if ($cache) {

			return $cache;

		}

		$table = $this->fullTableName($model);

		$fields = false;

		$cols = $this->_execute('SHOW FULL COLUMNS FROM ' . $table);

		if (!$cols) {

			throw new CakeException(__d('cake_dev', 'Could not describe table for %s', $table));

		}

		while ($column = $cols->fetch(PDO::FETCH_OBJ)) {

			$fields[$column->Field] = array(

				'type' => $this->column($column->Type),

				'null' => ($column->Null === 'YES' ? true : false),

				'default' => $column->Default,

				'length' => $this->length($column->Type)

			);

			if (in_array($fields[$column->Field]['type'], $this->fieldParameters['unsigned']['types'], true)) {

				$fields[$column->Field]['unsigned'] = $this->_unsigned($column->Type);

			}

			if ($fields[$column->Field]['type'] === 'timestamp' && strtoupper($column->Default) === 'CURRENT_TIMESTAMP') {

				$fields[$column->Field]['default'] = null;

			}

			if (!empty($column->Key) && isset($this->index[$column->Key])) {

				$fields[$column->Field]['key'] = $this->index[$column->Key];

			}

			foreach ($this->fieldParameters as $name => $value) {

				if (!empty($column->{$value['column']})) {

					$fields[$column->Field][$name] = $column->{$value['column']};

				}

			}

			if (isset($fields[$column->Field]['collate'])) {

				$charset = $this->getCharsetName($fields[$column->Field]['collate']);

				if ($charset) {

					$fields[$column->Field]['charset'] = $charset;

				}

			}

		}

		$this->_cacheDescription($key, $fields);

		$cols->closeCursor();

		return $fields;

	}

/**

 * Generates and executes an SQL UPDATE statement for given model, fields, and values.

 *

 * @param Model $model The model to update.

 * @param array $fields The fields to update.

 * @param array $values The values to set.

 * @param mixed $conditions The conditions to use.

 * @return array

 */

	public function update(Model $model, $fields = array(), $values = null, $conditions = null) {

		if (!$this->_useAlias) {

			return parent::update($model, $fields, $values, $conditions);

		}

		if (!$values) {

			$combined = $fields;

		} else {

			$combined = array_combine($fields, $values);

		}

		$alias = $joins = false;

		$fields = $this->_prepareUpdateFields($model, $combined, empty($conditions), !empty($conditions));

		$fields = implode(', ', $fields);

		$table = $this->fullTableName($model);

		if (!empty($conditions)) {

			$alias = $this->name($model->alias);

			if ($model->name === $model->alias) {

				$joins = implode(' ', $this->_getJoins($model));

			}

		}

		$conditions = $this->conditions($this->defaultConditions($model, $conditions, $alias), true, true, $model);

		if ($conditions === false) {

			return false;

		}

		if (!$this->execute($this->renderStatement('update', compact('table', 'alias', 'joins', 'fields', 'conditions')))) {

			$model->onError();

			return false;

		}

		return true;

	}

/**

 * Generates and executes an SQL DELETE statement for given id/conditions on given model.

 *

 * @param Model $model The model to delete from.

 * @param mixed $conditions The conditions to use.

 * @return bool Success

 */

	public function delete(Model $model, $conditions = null) {

		if (!$this->_useAlias) {

			return parent::delete($model, $conditions);

		}

		$alias = $this->name($model->alias);

		$table = $this->fullTableName($model);

		$joins = implode(' ', $this->_getJoins($model));

		if (empty($conditions)) {

			$alias = $joins = false;

		}

		$complexConditions = false;

		foreach ((array)$conditions as $key => $value) {

			if (strpos($key, $model->alias) === false) {

				$complexConditions = true;

				break;

			}

		}

		if (!$complexConditions) {

			$joins = false;

		}

		$conditions = $this->conditions($this->defaultConditions($model, $conditions, $alias), true, true, $model);

		if ($conditions === false) {

			return false;

		}

		if ($this->execute($this->renderStatement('delete', compact('alias', 'table', 'joins', 'conditions'))) === false) {

			$model->onError();

			return false;

		}

		return true;

	}

/**

 * Sets the database encoding

 *

 * @param string $enc Database encoding

 * @return bool

 */

	public function setEncoding($enc) {

		return $this->_execute('SET NAMES ' . $enc) !== false;

	}

/**

 * Returns an array of the indexes in given datasource name.

 *

 * @param string $model Name of model to inspect

 * @return array Fields in table. Keys are column and unique

 */

	public function index($model) {

		$index = array();

		$table = $this->fullTableName($model);

		$old = version_compare($this->getVersion(), '4.1', '<=');

		if ($table) {

			$indexes = $this->_execute('SHOW INDEX FROM ' . $table);

			// @codingStandardsIgnoreStart

			// MySQL columns don't match the cakephp conventions.

			while ($idx = $indexes->fetch(PDO::FETCH_OBJ)) {

				if ($old) {

					$idx = (object)current((array)$idx);

				}

				if (!isset($index[$idx->Key_name]['column'])) {

					$col = array();

					$index[$idx->Key_name]['column'] = $idx->Column_name;

					if ($idx->Index_type === 'FULLTEXT') {

						$index[$idx->Key_name]['type'] = strtolower($idx->Index_type);

					} else {

						$index[$idx->Key_name]['unique'] = (int)($idx->Non_unique == 0);

					}

				} else {

					if (!empty($index[$idx->Key_name]['column']) && !is_array($index[$idx->Key_name]['column'])) {

						$col[] = $index[$idx->Key_name]['column'];

					}

					$col[] = $idx->Column_name;

					$index[$idx->Key_name]['column'] = $col;

				}

				if (!empty($idx->Sub_part)) {

					if (!isset($index[$idx->Key_name]['length'])) {

						$index[$idx->Key_name]['length'] = array();

					}

					$index[$idx->Key_name]['length'][$idx->Column_name] = $idx->Sub_part;

				}

			}

			// @codingStandardsIgnoreEnd

			$indexes->closeCursor();

		}

		return $index;

	}

/**

 * Generate a MySQL Alter Table syntax for the given Schema comparison

 *

 * @param array $compare Result of a CakeSchema::compare()

 * @param string $table The table name.

 * @return array Array of alter statements to make.

 */

	public function alterSchema($compare, $table = null) {

		if (!is_array($compare)) {

			return false;

		}

		$out = '';

		$colList = array();

		foreach ($compare as $curTable => $types) {

			$indexes = $tableParameters = $colList = array();

			if (!$table || $table === $curTable) {

				$out .= 'ALTER TABLE ' . $this->fullTableName($curTable) . " \n";

				foreach ($types as $type => $column) {

					if (isset($column['indexes'])) {

						$indexes[$type] = $column['indexes'];

						unset($column['indexes']);

					}

					if (isset($column['tableParameters'])) {

						$tableParameters[$type] = $column['tableParameters'];

						unset($column['tableParameters']);

					}

					switch ($type) {

						case 'add':

							foreach ($column as $field => $col) {

								$col['name'] = $field;

								$alter = 'ADD ' . $this->buildColumn($col);

								if (isset($col['after'])) {

									$alter .= ' AFTER ' . $this->name($col['after']);

								}

								$colList[] = $alter;

							}

							break;

						case 'drop':

							foreach ($column as $field => $col) {

								$col['name'] = $field;

								$colList[] = 'DROP ' . $this->name($field);

							}

							break;

						case 'change':

							foreach ($column as $field => $col) {

								if (!isset($col['name'])) {

									$col['name'] = $field;

								}

								$alter = 'CHANGE ' . $this->name($field) . ' ' . $this->buildColumn($col);

								if (isset($col['after'])) {

									$alter .= ' AFTER ' . $this->name($col['after']);

								}

								$colList[] = $alter;

							}

							break;

					}

				}

				$colList = array_merge($colList, $this->_alterIndexes($curTable, $indexes));

				$colList = array_merge($colList, $this->_alterTableParameters($curTable, $tableParameters));

				$out .= "\t" . implode(",\n\t", $colList) . ";\n\n";

			}

		}

		return $out;

	}

/**

 * Generate a "drop table" statement for the given table

 *

 * @param type $table Name of the table to drop

 * @return string Drop table SQL statement

 */

	protected function _dropTable($table) {

		return 'DROP TABLE IF EXISTS ' . $this->fullTableName($table) . ";";

	}

/**

 * Generate MySQL table parameter alteration statements for a table.

 *

 * @param string $table Table to alter parameters for.

 * @param array $parameters Parameters to add & drop.

 * @return array Array of table property alteration statements.

 */

	protected function _alterTableParameters($table, $parameters) {

		if (isset($parameters['change'])) {

			return $this->buildTableParameters($parameters['change']);

		}

		return array();

	}

/**

 * Format indexes for create table

 *

 * @param array $indexes An array of indexes to generate SQL from

 * @param string $table Optional table name, not used

 * @return array An array of SQL statements for indexes

 * @see DboSource::buildIndex()

 */

	public function buildIndex($indexes, $table = null) {

		$join = array();

		foreach ($indexes as $name => $value) {

			$out = '';

			if ($name === 'PRIMARY') {

				$out .= 'PRIMARY ';

				$name = null;

			} else {

				if (!empty($value['unique'])) {

					$out .= 'UNIQUE ';

				}

				$name = $this->startQuote . $name . $this->endQuote;

			}

			if (isset($value['type']) && strtolower($value['type']) === 'fulltext') {

				$out .= 'FULLTEXT ';

			}

			$out .= 'KEY ' . $name . ' (';

			if (is_array($value['column'])) {

				if (isset($value['length'])) {

					$vals = array();

					foreach ($value['column'] as $column) {

						$name = $this->name($column);

						if (isset($value['length'])) {

							$name .= $this->_buildIndexSubPart($value['length'], $column);

						}

						$vals[] = $name;

					}

					$out .= implode(', ', $vals);

				} else {

					$out .= implode(', ', array_map(array(&$this, 'name'), $value['column']));

				}

			} else {

				$out .= $this->name($value['column']);

				if (isset($value['length'])) {

					$out .= $this->_buildIndexSubPart($value['length'], $value['column']);

				}

			}

			$out .= ')';

			$join[] = $out;

		}

		return $join;

	}

/**

 * Generate MySQL index alteration statements for a table.

 *

 * @param string $table Table to alter indexes for

 * @param array $indexes Indexes to add and drop

 * @return array Index alteration statements

 */

	protected function _alterIndexes($table, $indexes) {

		$alter = array();

		if (isset($indexes['drop'])) {

			foreach ($indexes['drop'] as $name => $value) {

				$out = 'DROP ';

				if ($name === 'PRIMARY') {

					$out .= 'PRIMARY KEY';

				} else {

					$out .= 'KEY ' . $this->startQuote . $name . $this->endQuote;

				}

				$alter[] = $out;

			}

		}

		if (isset($indexes['add'])) {

			$add = $this->buildIndex($indexes['add']);

			foreach ($add as $index) {

				$alter[] = 'ADD ' . $index;

			}

		}

		return $alter;

	}

/**

 * Format length for text indexes

 *

 * @param array $lengths An array of lengths for a single index

 * @param string $column The column for which to generate the index length

 * @return string Formatted length part of an index field

 */

	protected function _buildIndexSubPart($lengths, $column) {

		if ($lengths === null) {

			return '';

		}

		if (!isset($lengths[$column])) {

			return '';

		}

		return '(' . $lengths[$column] . ')';

	}

/**

 * Returns a detailed array of sources (tables) in the database.

 *

 * @param string $name Table name to get parameters

 * @return array Array of table names in the database

 */

	public function listDetailedSources($name = null) {

		$condition = '';

		if (is_string($name)) {

			$condition = ' WHERE name = ' . $this->value($name);

		}

		$result = $this->_connection->query('SHOW TABLE STATUS ' . $condition, PDO::FETCH_ASSOC);

		if (!$result) {

			$result->closeCursor();

			return array();

		}

		$tables = array();

		foreach ($result as $row) {

			$tables[$row['Name']] = (array)$row;

			unset($tables[$row['Name']]['queryString']);

			if (!empty($row['Collation'])) {

				$charset = $this->getCharsetName($row['Collation']);

				if ($charset) {

					$tables[$row['Name']]['charset'] = $charset;

				}

			}

		}

		$result->closeCursor();

		if (is_string($name) && isset($tables[$name])) {

			return $tables[$name];

		}

		return $tables;

	}

/**

 * Converts database-layer column types to basic types

 *

 * @param string $real Real database-layer column type (i.e. "varchar(255)")

 * @return string Abstract column type (i.e. "string")

 */

	public function column($real) {

		if (is_array($real)) {

			$col = $real['name'];

			if (isset($real['limit'])) {

				$col .= '(' . $real['limit'] . ')';

			}

			return $col;

		}

		$col = str_replace(')', '', $real);

		$limit = $this->length($real);

		if (strpos($col, '(') !== false) {

			list($col, $vals) = explode('(', $col);

		}

		if (in_array($col, array('date', 'time', 'datetime', 'timestamp'))) {

			return $col;

		}

		if (($col === 'tinyint' && $limit === 1) || $col === 'boolean') {

			return 'boolean';

		}

		if (strpos($col, 'bigint') !== false || $col === 'bigint') {

			return 'biginteger';

		}

		if (strpos($col, 'int') !== false) {

			return 'integer';

		}

		if (strpos($col, 'char') !== false || $col === 'tinytext') {

			return 'string';

		}

		if (strpos($col, 'text') !== false) {

			return 'text';

		}

		if (strpos($col, 'blob') !== false || $col === 'binary') {

			return 'binary';

		}

		if (strpos($col, 'float') !== false || strpos($col, 'double') !== false) {

			return 'float';

		}

		if (strpos($col, 'decimal') !== false || strpos($col, 'numeric') !== false) {

			return 'decimal';

		}

		if (strpos($col, 'enum') !== false) {

			return "enum($vals)";

		}

		if (strpos($col, 'set') !== false) {

			return "set($vals)";

		}

		return 'text';

	}

/**

 * {@inheritDoc}

 */

	public function value($data, $column = null, $null = true) {

		$value = parent::value($data, $column, $null);

		if (is_numeric($value) && substr($column, 0, 3) === 'set') {

			return $this->_connection->quote($value);

		}

		return $value;

	}

/**

 * Gets the schema name

 *

 * @return string The schema name

 */

	public function getSchemaName() {

		return $this->config['database'];

	}

/**

 * Check if the server support nested transactions

 *

 * @return bool

 */

	public function nestedTransactionSupported() {

		return $this->useNestedTransactions && version_compare($this->getVersion(), '4.1', '>=');

	}

/**

 * Check if column type is unsigned

 *

 * @param string $real Real database-layer column type (i.e. "varchar(255)")

 * @return bool True if column is unsigned, false otherwise

 */

	protected function _unsigned($real) {

		return strpos(strtolower($real), 'unsigned') !== false;

	}

}