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class Truncate in Drupal 9

Same name in this branch
  1. 9 core/lib/Drupal/Core/Database/Query/Truncate.php \Drupal\Core\Database\Query\Truncate
  2. 9 core/lib/Drupal/Core/Database/Driver/sqlite/Truncate.php \Drupal\Core\Database\Driver\sqlite\Truncate
  3. 9 core/lib/Drupal/Core/Database/Driver/pgsql/Truncate.php \Drupal\Core\Database\Driver\pgsql\Truncate
  4. 9 core/tests/fixtures/database_drivers/module/corefake/src/Driver/Database/corefakeWithAllCustomClasses/Truncate.php \Drupal\corefake\Driver\Database\corefakeWithAllCustomClasses\Truncate
  5. 9 core/modules/system/tests/modules/driver_test/src/Driver/Database/DrivertestPgsql/Truncate.php \Drupal\driver_test\Driver\Database\DrivertestPgsql\Truncate
Same name and namespace in other branches
  1. 8 core/lib/Drupal/Core/Database/Query/Truncate.php \Drupal\Core\Database\Query\Truncate

General class for an abstracted TRUNCATE operation.

Hierarchy

Expanded class hierarchy of Truncate

4 files declare their use of Truncate
Connection.php in core/lib/Drupal/Core/Database/Connection.php
Truncate.php in core/lib/Drupal/Core/Database/Driver/sqlite/Truncate.php
Truncate.php in core/lib/Drupal/Core/Database/Driver/pgsql/Truncate.php
Truncate.php in core/tests/fixtures/database_drivers/module/corefake/src/Driver/Database/corefakeWithAllCustomClasses/Truncate.php
3 string references to 'Truncate'
Connection::getDriverClass in core/lib/Drupal/Core/Database/Connection.php
Gets the driver-specific override class if any for the specified class.
Connection::truncate in core/lib/Drupal/Core/Database/Connection.php
Prepares and returns a TRUNCATE query object.
ConnectionTest::providerGetDriverClass in core/tests/Drupal/Tests/Core/Database/ConnectionTest.php
Data provider for testGetDriverClass().

File

core/lib/Drupal/Core/Database/Query/Truncate.php, line 11

Namespace

Drupal\Core\Database\Query
View source
class Truncate extends Query {

  /**
   * The table to truncate.
   *
   * @var string
   */
  protected $table;

  /**
   * Constructs a Truncate query object.
   *
   * @param \Drupal\Core\Database\Connection $connection
   *   A Connection object.
   * @param string $table
   *   Name of the table to associate with this query.
   * @param array $options
   *   Array of database options.
   */
  public function __construct(Connection $connection, $table, array $options = []) {
    $options['return'] = Database::RETURN_AFFECTED;
    parent::__construct($connection, $options);
    $this->table = $table;
  }

  /**
   * {@inheritdoc}
   */
  public function compile(Connection $connection, PlaceholderInterface $queryPlaceholder) {
    return $this->condition
      ->compile($connection, $queryPlaceholder);
  }

  /**
   * {@inheritdoc}
   */
  public function compiled() {
    return $this->condition
      ->compiled();
  }

  /**
   * Executes the TRUNCATE query.
   *
   * @return
   *   Return value is dependent on whether the executed SQL statement is a
   *   TRUNCATE or a DELETE. TRUNCATE is DDL and no information on affected
   *   rows is available. DELETE is DML and will return the number of affected
   *   rows. In general, do not rely on the value returned by this method in
   *   calling code.
   *
   * @see https://learnsql.com/blog/difference-between-truncate-delete-and-drop-table-in-sql
   */
  public function execute() {
    $stmt = $this->connection
      ->prepareStatement((string) $this, $this->queryOptions, TRUE);
    try {
      $stmt
        ->execute([], $this->queryOptions);
      return $stmt
        ->rowCount();
    } catch (\Exception $e) {
      $this->connection
        ->exceptionHandler()
        ->handleExecutionException($e, $stmt, [], $this->queryOptions);
    }
  }

  /**
   * Implements PHP magic __toString method to convert the query to a string.
   *
   * @return string
   *   The prepared statement.
   */
  public function __toString() {

    // Create a sanitized comment string to prepend to the query.
    $comments = $this->connection
      ->makeComment($this->comments);

    // In most cases, TRUNCATE is not a transaction safe statement as it is a
    // DDL statement which results in an implicit COMMIT. When we are in a
    // transaction, fallback to the slower, but transactional, DELETE.
    // PostgreSQL also locks the entire table for a TRUNCATE strongly reducing
    // the concurrency with other transactions.
    if ($this->connection
      ->inTransaction()) {
      return $comments . 'DELETE FROM {' . $this->connection
        ->escapeTable($this->table) . '}';
    }
    else {
      return $comments . 'TRUNCATE {' . $this->connection
        ->escapeTable($this->table) . '} ';
    }
  }

}

Members

Namesort descending Modifiers Type Description Overrides
Query::$comments protected property An array of comments that can be prepended to a query.
Query::$connection protected property The connection object on which to run this query.
Query::$connectionKey protected property The key of the connection object.
Query::$connectionTarget protected property The target of the connection object.
Query::$nextPlaceholder protected property The placeholder counter.
Query::$queryOptions protected property The query options to pass on to the connection object.
Query::$uniqueIdentifier protected property A unique identifier for this query object.
Query::comment public function Adds a comment to the query.
Query::getComments public function Returns a reference to the comments array for the query.
Query::getConnection public function Gets the database connection to be used for the query.
Query::nextPlaceholder public function Gets the next placeholder value for this query object. Overrides PlaceholderInterface::nextPlaceholder
Query::uniqueIdentifier public function Returns a unique identifier for this object. Overrides PlaceholderInterface::uniqueIdentifier
Query::__clone public function Implements the magic __clone function. 1
Query::__sleep public function Implements the magic __sleep function to disconnect from the database.
Query::__wakeup public function Implements the magic __wakeup function to reconnect to the database.
Truncate::$table protected property The table to truncate.
Truncate::compile public function
Truncate::compiled public function
Truncate::execute public function Executes the TRUNCATE query. Overrides Query::execute 1
Truncate::__construct public function Constructs a Truncate query object. Overrides Query::__construct
Truncate::__toString public function Implements PHP magic __toString method to convert the query to a string. Overrides Query::__toString 1