class Connection in Drupal 9

MySQL implementation of \Drupal\Core\Database\Connection.

Hierarchy

• class \Drupal\Core\Database\Connection
  • class \Drupal\Core\Database\Driver\mysql\Connection

Related topics

Database abstraction layer

Allow the use of different database servers using the same code base.

6 files declare their use of Connection

Connection.php in core/modules/system/tests/modules/database_statement_monitoring_test/src/mysql/Connection.php

Connection.php in core/modules/system/tests/modules/driver_test/src/Driver/Database/DrivertestMysql/Connection.php

Connection.php in core/modules/system/tests/modules/driver_test/src/Driver/Database/DrivertestMysqlDeprecatedVersion/Connection.php

ConnectionTest.php in core/tests/Drupal/Tests/Core/Database/Driver/mysql/ConnectionTest.php

Tasks.php in core/lib/Drupal/Core/Database/Driver/mysql/Install/Tasks.php

... See full list

File

core/lib/Drupal/Core/Database/Driver/mysql/Connection.php, line 24

Namespace

Drupal\Core\Database\Driver\mysql

class Connection extends DatabaseConnection {

  /**
   * Error code for "Unknown database" error.
   */
  const DATABASE_NOT_FOUND = 1049;

  /**
   * Error code for "Access denied" error.
   */
  const ACCESS_DENIED = 1045;

  /**
   * Error code for "Can't initialize character set" error.
   */
  const UNSUPPORTED_CHARSET = 2019;

  /**
   * Driver-specific error code for "Unknown character set" error.
   */
  const UNKNOWN_CHARSET = 1115;

  /**
   * SQLSTATE error code for "Syntax error or access rule violation".
   */
  const SQLSTATE_SYNTAX_ERROR = 42000;

  /**
   * {@inheritdoc}
   */
  protected $statementClass = NULL;

  /**
   * {@inheritdoc}
   */
  protected $statementWrapperClass = StatementWrapper::class;

  /**
   * Flag to indicate if the cleanup function in __destruct() should run.
   *
   * @var bool
   */
  protected $needsCleanup = FALSE;

  /**
   * Stores the server version after it has been retrieved from the database.
   *
   * @var string
   *
   * @see \Drupal\Core\Database\Driver\mysql\Connection::version
   */
  private $serverVersion;

  /**
   * The minimal possible value for the max_allowed_packet setting of MySQL.
   *
   * @link https://mariadb.com/kb/en/mariadb/server-system-variables/#max_allowed_packet
   * @link https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_max_allowed_packet
   *
   * @var int
   */
  const MIN_MAX_ALLOWED_PACKET = 1024;

  /**
   * {@inheritdoc}
   */
  protected $identifierQuotes = [
    '"',
    '"',
  ];

  /**
   * {@inheritdoc}
   */
  public function __construct(\PDO $connection, array $connection_options) {

    // If the SQL mode doesn't include 'ANSI_QUOTES' (explicitly or via a
    // combination mode), then MySQL doesn't interpret a double quote as an
    // identifier quote, in which case use the non-ANSI-standard backtick.
    //
    // Because we still support MySQL 5.7, check for the deprecated combination
    // modes as well.
    //
    // @see https://dev.mysql.com/doc/refman/5.7/en/sql-mode.html#sqlmode_ansi_quotes
    $ansi_quotes_modes = [
      'ANSI_QUOTES',
      'ANSI',
      'DB2',
      'MAXDB',
      'MSSQL',
      'ORACLE',
      'POSTGRESQL',
    ];
    $is_ansi_quotes_mode = FALSE;
    foreach ($ansi_quotes_modes as $mode) {

      // None of the modes in $ansi_quotes_modes are substrings of other modes
      // that are not in $ansi_quotes_modes, so a simple stripos() does not
      // return false positives.
      if (stripos($connection_options['init_commands']['sql_mode'], $mode) !== FALSE) {
        $is_ansi_quotes_mode = TRUE;
        break;
      }
    }
    if ($this->identifierQuotes === [
      '"',
      '"',
    ] && !$is_ansi_quotes_mode) {
      $this->identifierQuotes = [
        '`',
        '`',
      ];
    }
    parent::__construct($connection, $connection_options);
  }

  /**
   * {@inheritdoc}
   */
  protected function handleQueryException(\PDOException $e, $query, array $args = [], $options = []) {

    // In case of attempted INSERT of a record with an undefined column and no
    // default value indicated in schema, MySql returns a 1364 error code.
    // Throw an IntegrityConstraintViolationException here like the other
    // drivers do, to avoid the parent class to throw a generic
    // DatabaseExceptionWrapper instead.
    if (!empty($e->errorInfo[1]) && $e->errorInfo[1] === 1364) {
      @trigger_error('Connection::handleQueryException() is deprecated in drupal:9.2.0 and is removed in drupal:10.0.0. Get a handler through $this->exceptionHandler() instead, and use one of its methods. See https://www.drupal.org/node/3187222', E_USER_DEPRECATED);
      $query_string = $query instanceof StatementInterface ? $query
        ->getQueryString() : $query;
      $message = $e
        ->getMessage() . ": " . $query_string . "; " . print_r($args, TRUE);
      throw new IntegrityConstraintViolationException($message, is_int($e
        ->getCode()) ? $e
        ->getCode() : 0, $e);
    }
    parent::handleQueryException($e, $query, $args, $options);
  }

  /**
   * {@inheritdoc}
   */
  public static function open(array &$connection_options = []) {
    if (isset($connection_options['_dsn_utf8_fallback']) && $connection_options['_dsn_utf8_fallback'] === TRUE) {

      // Only used during the installer version check, as a fallback from utf8mb4.
      $charset = 'utf8';
    }
    else {
      $charset = 'utf8mb4';
    }

    // 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']);
    }

    // Character set is added to dsn to ensure PDO uses the proper character
    // set when escaping. This has security implications. See
    // https://www.drupal.org/node/1201452 for further discussion.
    $dsn .= ';charset=' . $charset;
    if (!empty($connection_options['database'])) {
      $dsn .= ';dbname=' . $connection_options['database'];
    }

    // Allow PDO options to be overridden.
    $connection_options += [
      'pdo' => [],
    ];
    $connection_options['pdo'] += [
      \PDO::ATTR_ERRMODE => \PDO::ERRMODE_EXCEPTION,
      // So we don't have to mess around with cursors and unbuffered queries by default.
      \PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => TRUE,
      // Make sure MySQL returns all matched rows on update queries including
      // rows that actually didn't have to be updated because the values didn't
      // change. This matches common behavior among other database systems.
      \PDO::MYSQL_ATTR_FOUND_ROWS => TRUE,
      // Because MySQL's prepared statements skip the query cache, because it's dumb.
      \PDO::ATTR_EMULATE_PREPARES => TRUE,
      // Limit SQL to a single statement like mysqli.
      \PDO::MYSQL_ATTR_MULTI_STATEMENTS => FALSE,
      // Convert numeric values to strings when fetching. In PHP 8.1,
      // \PDO::ATTR_EMULATE_PREPARES now behaves the same way as non emulated
      // prepares and returns integers. See https://externals.io/message/113294
      // for further discussion.
      \PDO::ATTR_STRINGIFY_FETCHES => TRUE,
    ];
    try {
      $pdo = new \PDO($dsn, $connection_options['username'], $connection_options['password'], $connection_options['pdo']);
    } catch (\PDOException $e) {
      if ($e
        ->getCode() == static::DATABASE_NOT_FOUND) {
        throw new DatabaseNotFoundException($e
          ->getMessage(), $e
          ->getCode(), $e);
      }
      if ($e
        ->getCode() == static::ACCESS_DENIED) {
        throw new DatabaseAccessDeniedException($e
          ->getMessage(), $e
          ->getCode(), $e);
      }
      throw $e;
    }

    // Force MySQL to use the UTF-8 character set. Also set the collation, if a
    // certain one has been set; otherwise, MySQL defaults to
    // 'utf8mb4_general_ci' (MySQL 5) or 'utf8mb4_0900_ai_ci' (MySQL 8) for
    // utf8mb4.
    if (!empty($connection_options['collation'])) {
      $pdo
        ->exec('SET NAMES ' . $charset . ' COLLATE ' . $connection_options['collation']);
    }
    else {
      $pdo
        ->exec('SET NAMES ' . $charset);
    }

    // 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
    // https://www.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 += [
      'init_commands' => [],
    ];
    $connection_options['init_commands'] += [
      'sql_mode' => "SET sql_mode = 'ANSI,TRADITIONAL'",
    ];

    // Execute initial commands.
    foreach ($connection_options['init_commands'] as $sql) {
      $pdo
        ->exec($sql);
    }
    return $pdo;
  }

  /**
   * {@inheritdoc}
   */
  public function __destruct() {
    if ($this->needsCleanup) {
      $this
        ->nextIdDelete();
    }
    parent::__destruct();
  }
  public function queryRange($query, $from, $count, array $args = [], array $options = []) {
    return $this
      ->query($query . ' LIMIT ' . (int) $from . ', ' . (int) $count, $args, $options);
  }

  /**
   * {@inheritdoc}
   */
  public function queryTemporary($query, array $args = [], array $options = []) {
    @trigger_error('Connection::queryTemporary() is deprecated in drupal:9.3.0 and is removed from drupal:10.0.0. There is no replacement. See https://www.drupal.org/node/3211781', E_USER_DEPRECATED);
    $tablename = $this
      ->generateTemporaryTableName();
    $this
      ->query('CREATE TEMPORARY TABLE {' . $tablename . '} Engine=MEMORY ' . $query, $args, $options);
    return $tablename;
  }
  public function driver() {
    return 'mysql';
  }

  /**
   * {@inheritdoc}
   */
  public function version() {
    if ($this
      ->isMariaDb()) {
      return $this
        ->getMariaDbVersionMatch();
    }
    return $this
      ->getServerVersion();
  }

  /**
   * Determines whether the MySQL distribution is MariaDB or not.
   *
   * @return bool
   *   Returns TRUE if the distribution is MariaDB, or FALSE if not.
   */
  public function isMariaDb() : bool {
    return (bool) $this
      ->getMariaDbVersionMatch();
  }

  /**
   * Gets the MariaDB portion of the server version.
   *
   * @return string
   *   The MariaDB portion of the server version if present, or NULL if not.
   */
  protected function getMariaDbVersionMatch() : ?string {

    // MariaDB may prefix its version string with '5.5.5-', which should be
    // ignored.
    // @see https://github.com/MariaDB/server/blob/f6633bf058802ad7da8196d01fd19d75c53f7274/include/mysql_com.h#L42.
    $regex = '/^(?:5\\.5\\.5-)?(\\d+\\.\\d+\\.\\d+.*-mariadb.*)/i';
    preg_match($regex, $this
      ->getServerVersion(), $matches);
    return empty($matches[1]) ? NULL : $matches[1];
  }

  /**
   * Gets the server version.
   *
   * @return string
   *   The PDO server version.
   */
  protected function getServerVersion() : string {
    if (!$this->serverVersion) {
      $this->serverVersion = $this->connection
        ->query('SELECT VERSION()')
        ->fetchColumn();
    }
    return $this->serverVersion;
  }
  public function databaseType() {
    return 'mysql';
  }

  /**
   * Overrides \Drupal\Core\Database\Connection::createDatabase().
   *
   * @param string $database
   *   The name of the database to create.
   *
   * @throws \Drupal\Core\Database\DatabaseNotFoundException
   */
  public function createDatabase($database) {

    // Escape the database name.
    $database = Database::getConnection()
      ->escapeDatabase($database);
    try {

      // Create the database and set it as active.
      $this->connection
        ->exec("CREATE DATABASE {$database}");
      $this->connection
        ->exec("USE {$database}");
    } catch (\Exception $e) {
      throw new DatabaseNotFoundException($e
        ->getMessage());
    }
  }
  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 ()', [], [
      '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', [
        ':value' => $existing_id,
      ]);
      $new_id = $this
        ->query('INSERT INTO {sequences} () VALUES ()', [], [
        'return' => Database::RETURN_INSERT_ID,
      ]);
    }
    $this->needsCleanup = 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 ::delete().
      $this
        ->query('DELETE FROM {sequences} WHERE value < :value', [
        ':value' => $max_id,
      ]);
    } catch (DatabaseException $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)) {
        $this
          ->doCommit();
      }
      else {

        // Attempt to release this savepoint in the standard way.
        try {
          $this
            ->query('RELEASE SAVEPOINT ' . $name);
        } catch (DatabaseExceptionWrapper $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
            ->getPrevious()->errorInfo[1] == '1305') {

            // If one SAVEPOINT was released automatically, then all were.
            // Therefore, clean the transaction stack.
            $this->transactionLayers = [];

            // We also have to explain to PDO that the transaction stack has
            // been cleaned-up.
            $this
              ->doCommit();
          }
          else {
            throw $e;
          }
        }
      }
    }
  }

  /**
   * {@inheritdoc}
   */
  public function rollBack($savepoint_name = 'drupal_transaction') {

    // MySQL will automatically commit transactions when tables are altered or
    // created (DDL transactions are not supported). Prevent triggering an
    // exception to ensure that the error that has caused the rollback is
    // properly reported.
    if (!$this->connection
      ->inTransaction()) {

      // On PHP 7 $this->connection->inTransaction() will return TRUE and
      // $this->connection->rollback() does not throw an exception; the
      // following code is unreachable.
      // If \Drupal\Core\Database\Connection::rollBack() would throw an
      // exception then continue to throw an exception.
      if (!$this
        ->inTransaction()) {
        throw new TransactionNoActiveException();
      }

      // A previous rollback to an earlier savepoint may mean that the savepoint
      // in question has already been accidentally committed.
      if (!isset($this->transactionLayers[$savepoint_name])) {
        throw new TransactionNoActiveException();
      }
      trigger_error('Rollback attempted when there is no active transaction. This can cause data integrity issues.', E_USER_WARNING);
      return;
    }
    return parent::rollBack($savepoint_name);
  }

  /**
   * {@inheritdoc}
   */
  protected function doCommit() {

    // MySQL will automatically commit transactions when tables are altered or
    // created (DDL transactions are not supported). Prevent triggering an
    // exception in this case as all statements have been committed.
    if ($this->connection
      ->inTransaction()) {

      // On PHP 7 $this->connection->inTransaction() will return TRUE and
      // $this->connection->commit() does not throw an exception.
      $success = parent::doCommit();
    }
    else {

      // Process the post-root (non-nested) transaction commit callbacks. The
      // following code is copied from
      // \Drupal\Core\Database\Connection::doCommit()
      $success = TRUE;
      if (!empty($this->rootTransactionEndCallbacks)) {
        $callbacks = $this->rootTransactionEndCallbacks;
        $this->rootTransactionEndCallbacks = [];
        foreach ($callbacks as $callback) {
          call_user_func($callback, $success);
        }
      }
    }
    return $success;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Connection::$connection	protected	property	The actual PDO connection.
Connection::$connectionOptions	protected	property	The connection information for this connection object.
Connection::$driverClasses	protected	property	Index of what driver-specific class to use for various operations.
Connection::$escapedAliases	protected	property	List of escaped aliases names, keyed by unescaped aliases.
Connection::$escapedFields	protected	property	List of escaped field names, keyed by unescaped names.
Connection::$escapedNames Deprecated	protected	property	List of escaped database, table, and field names, keyed by unescaped names.
Connection::$escapedTables	protected	property	List of escaped table names, keyed by unescaped names.
Connection::$identifierQuotes	protected	property	The identifier quote characters for the database type. Overrides Connection::$identifierQuotes
Connection::$key	protected	property	The key representing this connection.
Connection::$logger	protected	property	The current database logging object for this connection.
Connection::$needsCleanup	protected	property	Flag to indicate if the cleanup function in __destruct() should run.
Connection::$prefixes	protected	property	The prefixes used by this database connection.
Connection::$prefixReplace	protected	property	List of replacement values for use in prefixTables().
Connection::$prefixSearch	protected	property	List of search values for use in prefixTables().
Connection::$rootTransactionEndCallbacks	protected	property	Post-root (non-nested) transaction commit callbacks.
Connection::$schema	protected	property	The schema object for this connection.
Connection::$serverVersion	private	property	Stores the server version after it has been retrieved from the database.
Connection::$statementClass	protected	property	The name of the Statement class for this connection. Overrides Connection::$statementClass
Connection::$statementWrapperClass	protected	property	The name of the StatementWrapper class for this connection. Overrides Connection::$statementWrapperClass
Connection::$target	protected	property	The database target this connection is for.
Connection::$temporaryNameIndex Deprecated	protected	property	An index used to generate unique temporary table names.
Connection::$transactionalDDLSupport	protected	property	Whether this database connection supports transactional DDL.	2
Connection::$transactionLayers	protected	property	Tracks the number of "layers" of transactions currently active.
Connection::$unprefixedTablesMap	protected	property	List of un-prefixed table names, keyed by prefixed table names.
Connection::ACCESS_DENIED		constant	Error code for "Access denied" error.
Connection::addRootTransactionEndCallback	public	function	Adds a root transaction end callback.
Connection::clientVersion	public	function	Returns the version of the database client.
Connection::commit	public	function	Throws an exception to deny direct access to transaction commits.
Connection::condition	public	function	Prepares and returns a CONDITION query object.
Connection::createConnectionOptionsFromUrl	public static	function	Creates an array of database connection options from a URL.	1
Connection::createDatabase	public	function	Overrides \Drupal\Core\Database\Connection::createDatabase(). Overrides Connection::createDatabase
Connection::createUrlFromConnectionOptions	public static	function	Creates a URL from an array of database connection options.	1
Connection::databaseType	public	function	Returns the name of the PDO driver for this connection. Overrides Connection::databaseType
Connection::DATABASE_NOT_FOUND		constant	Error code for "Unknown database" error.
Connection::defaultOptions	protected	function	Returns the default query options for any given query.
Connection::delete	public	function	Prepares and returns a DELETE query object.
Connection::destroy Deprecated	public	function	Destroys this Connection object.
Connection::doCommit	protected	function	Do the actual commit, invoke post-commit callbacks. Overrides Connection::doCommit
Connection::driver	public	function	Returns the type of database driver. Overrides Connection::driver
Connection::escapeAlias	public	function	Escapes an alias name string.
Connection::escapeDatabase	public	function	Escapes a database name string.
Connection::escapeField	public	function	Escapes a field name string.
Connection::escapeLike	public	function	Escapes characters that work as wildcard characters in a LIKE pattern.
Connection::escapeTable	public	function	Escapes a table name string.
Connection::exceptionHandler	public	function	Returns the database exceptions handler.
Connection::expandArguments	protected	function	Expands out shorthand placeholders.
Connection::filterComment	protected	function	Sanitize a query comment string.
Connection::generateTemporaryTableName Deprecated	protected	function	Generates a temporary table name.
Connection::getConnectionOptions	public	function	Returns the connection information for this connection object.
Connection::getDriverClass	public	function	Gets the driver-specific override class if any for the specified class.
Connection::getFullQualifiedTableName	public	function	Get a fully qualified table name.	2
Connection::getKey	public	function	Returns the key this connection is associated with.
Connection::getLogger	public	function	Gets the current logging object for this connection.
Connection::getMariaDbVersionMatch	protected	function	Gets the MariaDB portion of the server version.
Connection::getPagerManager	public	function	Get the pager manager service, if available.
Connection::getProvider	public	function	Get the module name of the module that is providing the database driver.
Connection::getServerVersion	protected	function	Gets the server version.	1
Connection::getSQLState	protected static	function	Extracts the SQLSTATE error from the PDOException.
Connection::getTarget	public	function	Returns the target this connection is associated with.
Connection::getUnprefixedTablesMap	public	function	Gets a list of individually prefixed table names.
Connection::handleQueryException	protected	function	Wraps and re-throws any PDO exception thrown by static::query(). Overrides Connection::handleQueryException
Connection::insert	public	function	Prepares and returns an INSERT query object.
Connection::inTransaction	public	function	Determines if there is an active transaction open.
Connection::isMariaDb	public	function	Determines whether the MySQL distribution is MariaDB or not.	1
Connection::makeComment	public	function	Flatten an array of query comments into a single comment string.
Connection::makeSequenceName	public	function	Creates the appropriate sequence name for a given table and serial field.
Connection::mapConditionOperator	public	function	Gets any special processing requirements for the condition operator. Overrides Connection::mapConditionOperator
Connection::merge	public	function	Prepares and returns a MERGE query object.
Connection::MIN_MAX_ALLOWED_PACKET		constant	The minimal possible value for the max_allowed_packet setting of MySQL.
Connection::nextId	public	function	Retrieves a unique ID from a given sequence. Overrides Connection::nextId
Connection::nextIdDelete	public	function
Connection::open	public static	function	Opens a PDO connection. Overrides Connection::open
Connection::popCommittableTransactions	protected	function	Overridden to work around issues to MySQL not supporting transactional DDL. Overrides Connection::popCommittableTransactions
Connection::popTransaction	public	function	Decreases the depth of transaction nesting.
Connection::prefixTables	public	function	Appends a database prefix to all tables in a query.
Connection::prepare Deprecated	public	function	Prepares a statement for execution and returns a statement object.	1
Connection::prepareQuery Deprecated	public	function	Prepares a query string and returns the prepared statement.
Connection::prepareStatement	public	function	Returns a prepared statement given a SQL string.	2
Connection::preprocessStatement	protected	function	Returns a string SQL statement ready for preparation.
Connection::pushTransaction	public	function	Increases the depth of transaction nesting.
Connection::query	public	function	Executes a query string against the database.	1
Connection::queryRange	public	function	Runs a limited-range query on this database object. Overrides Connection::queryRange
Connection::queryTemporary	public	function	Runs a SELECT query and stores its results in a temporary table. Overrides Connection::queryTemporary
Connection::quote	public	function	Quotes a string for use in a query.
Connection::quoteIdentifiers	public	function	Quotes all identifiers in a query.
Connection::rollBack	public	function	Rolls back the transaction entirely or to a named savepoint. Overrides Connection::rollBack
Connection::schema	public	function	Returns a DatabaseSchema object for manipulating the schema.
Connection::select	public	function	Prepares and returns a SELECT query object.
Connection::setKey	public	function	Tells this connection object what its key is.
Connection::setLogger	public	function	Associates a logging object with this connection.
Connection::setPrefix	protected	function	Set the list of prefixes used by this database connection.
Connection::setTarget	public	function	Tells this connection object what its target value is.
Connection::SQLSTATE_SYNTAX_ERROR		constant	SQLSTATE error code for "Syntax error or access rule violation".
Connection::startTransaction	public	function	Returns a new DatabaseTransaction object on this connection.
Connection::supportsTransactionalDDL	public	function	Determines if this driver supports transactional DDL.
Connection::supportsTransactions Deprecated	public	function	Determines if this driver supports transactions.
Connection::tablePrefix	public	function	Find the prefix for a table.
Connection::transactionDepth	public	function	Determines the current transaction depth.
Connection::truncate	public	function	Prepares and returns a TRUNCATE query object.
Connection::UNKNOWN_CHARSET		constant	Driver-specific error code for "Unknown character set" error.
Connection::UNSUPPORTED_CHARSET		constant	Error code for "Can't initialize character set" error.
Connection::update	public	function	Prepares and returns an UPDATE query object.
Connection::upsert	public	function	Prepares and returns an UPSERT query object.
Connection::version	public	function	Returns the version of the database server. Overrides Connection::version
Connection::__construct	public	function	Constructs a Connection object. Overrides Connection::__construct
Connection::__destruct	public	function	Ensures that the PDO connection can be garbage collected. Overrides Connection::__destruct
Connection::__sleep	public	function	Prevents the database connection from being serialized.