transactionSupport = !isset($connection_options['transactions']) || ($connection_options['transactions'] !== FALSE); // MySQL never supports transactional DDL. $this->transactionalDDLSupport = FALSE; $this->connectionOptions = $connection_options; // The DSN should use either a socket or a host/port. if (isset($connection_options['unix_socket'])) { $dsn = 'mysql:unix_socket=' . $connection_options['unix_socket']; } else { // Default to TCP connection on port 3306. $dsn = 'mysql:host=' . $connection_options['host'] . ';port=' . (empty($connection_options['port']) ? 3306 : $connection_options['port']); } $dsn .= ';dbname=' . $connection_options['database']; // Allow PDO options to be overridden. $connection_options += array( 'pdo' => array(), ); $connection_options['pdo'] += array( // So we don't have to mess around with cursors and unbuffered queries by default. PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE, // Because MySQL's prepared statements skip the query cache, because it's dumb. PDO::ATTR_EMULATE_PREPARES => TRUE, ); parent::__construct($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']); // Force MySQL to use the UTF-8 character set. Also set the collation, if a // certain one has been set; otherwise, MySQL defaults to 'utf8_general_ci' // for UTF-8. if (!empty($connection_options['collation'])) { $this->exec('SET NAMES utf8 COLLATE ' . $connection_options['collation']); } else { $this->exec('SET NAMES utf8'); } // Set MySQL init_commands if not already defined. Default Drupal's MySQL // behavior to conform more closely to SQL standards. This allows Drupal // to run almost seamlessly on many different kinds of database systems. // These settings force MySQL to behave the same as postgresql, or sqlite // in regards to syntax interpretation and invalid data handling. See // http://drupal.org/node/344575 for further discussion. Also, as MySQL 5.5 // changed the meaning of TRADITIONAL we need to spell out the modes one by // one. $connection_options += array( 'init_commands' => array(), ); $connection_options['init_commands'] += array( 'sql_mode' => "SET sql_mode = 'ANSI,STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER'", ); // Set connection options. $this->exec(implode('; ', $connection_options['init_commands'])); } public function queryRange($query, $from, $count, array $args = array(), array $options = array()) { return $this->query($query . ' LIMIT ' . (int) $from . ', ' . (int) $count, $args, $options); } public function queryTemporary($query, array $args = array(), array $options = array()) { $tablename = $this->generateTemporaryTableName(); $this->query(preg_replace('/^SELECT/i', 'CREATE TEMPORARY TABLE {' . $tablename . '} Engine=MEMORY SELECT', $query), $args, $options); return $tablename; } public function driver() { return 'mysql'; } public function databaseType() { return 'mysql'; } public function mapConditionOperator($operator) { // We don't want to override any of the defaults. return NULL; } public function nextId($existing_id = 0) { $new_id = $this->query('INSERT INTO {sequences} () VALUES ()', array(), array('return' => Database::RETURN_INSERT_ID)); // This should only happen after an import or similar event. if ($existing_id >= $new_id) { // If we INSERT a value manually into the sequences table, on the next // INSERT, MySQL will generate a larger value. However, there is no way // of knowing whether this value already exists in the table. MySQL // provides an INSERT IGNORE which would work, but that can mask problems // other than duplicate keys. Instead, we use INSERT ... ON DUPLICATE KEY // UPDATE in such a way that the UPDATE does not do anything. This way, // duplicate keys do not generate errors but everything else does. $this->query('INSERT INTO {sequences} (value) VALUES (:value) ON DUPLICATE KEY UPDATE value = value', array(':value' => $existing_id)); $new_id = $this->query('INSERT INTO {sequences} () VALUES ()', array(), array('return' => Database::RETURN_INSERT_ID)); } if (!$this->shutdownRegistered) { // Use register_shutdown_function() here to keep the database system // independent of Drupal. register_shutdown_function(array($this, 'nextIdDelete')); $shutdownRegistered = TRUE; } return $new_id; } public function nextIdDelete() { // While we want to clean up the table to keep it up from occupying too // much storage and memory, we must keep the highest value in the table // because InnoDB uses an in-memory auto-increment counter as long as the // server runs. When the server is stopped and restarted, InnoDB // reinitializes the counter for each table for the first INSERT to the // table based solely on values from the table so deleting all values would // be a problem in this case. Also, TRUNCATE resets the auto increment // counter. try { $max_id = $this->query('SELECT MAX(value) FROM {sequences}')->fetchField(); // We know we are using MySQL here, no need for the slower db_delete(). $this->query('DELETE FROM {sequences} WHERE value < :value', array(':value' => $max_id)); } // During testing, this function is called from shutdown with the // simpletest prefix stored in $this->connection, and those tables are gone // by the time shutdown is called so we need to ignore the database // errors. There is no problem with completely ignoring errors here: if // these queries fail, the sequence will work just fine, just use a bit // more database storage and memory. catch (PDOException $e) { } } /** * Overridden to work around issues to MySQL not supporting transactional DDL. */ protected function popCommittableTransactions() { // Commit all the committable layers. foreach (array_reverse($this->transactionLayers) as $name => $active) { // Stop once we found an active transaction. if ($active) { break; } // If there are no more layers left then we should commit. unset($this->transactionLayers[$name]); if (empty($this->transactionLayers)) { if (!PDO::commit()) { throw new DatabaseTransactionCommitFailedException(); } } else { // Attempt to release this savepoint in the standard way. try { $this->query('RELEASE SAVEPOINT ' . $name); } catch (PDOException $e) { // However, in MySQL (InnoDB), savepoints are automatically committed // when tables are altered or created (DDL transactions are not // supported). This can cause exceptions due to trying to release // savepoints which no longer exist. // // To avoid exceptions when no actual error has occurred, we silently // succeed for MySQL error code 1305 ("SAVEPOINT does not exist"). if ($e->errorInfo[1] == '1305') { // If one SAVEPOINT was released automatically, then all were. // Therefore, clean the transaction stack. $this->transactionLayers = array(); // We also have to explain to PDO that the transaction stack has // been cleaned-up. PDO::commit(); } else { throw $e; } } } } } } /** * @} End of "addtogroup database". */