class Statement in Drupal 8

SQLite implementation of \Drupal\Core\Database\Statement.

The PDO SQLite driver only closes SELECT statements when the PDOStatement destructor is called and SQLite does not allow data change (INSERT, UPDATE etc) on a table which has open SELECT statements. This is a user-space mock of PDOStatement that buffers all the data and doesn't have those limitations.

Hierarchy

• class \Drupal\Core\Database\StatementPrefetch implements \Drupal\Core\Database\Iterator, StatementInterface
  • class \Drupal\Core\Database\Driver\sqlite\Statement implements StatementInterface

File

core/lib/Drupal/Core/Database/Driver/sqlite/Statement.php, line 17

Namespace

Drupal\Core\Database\Driver\sqlite

class Statement extends StatementPrefetch implements StatementInterface {

  /**
   * {@inheritdoc}
   *
   * The PDO SQLite layer doesn't replace numeric placeholders in queries
   * correctly, and this makes numeric expressions (such as COUNT(*) >= :count)
   * fail. We replace numeric placeholders in the query ourselves to work
   * around this bug.
   *
   * See http://bugs.php.net/bug.php?id=45259 for more details.
   */
  protected function getStatement($query, &$args = []) {
    if (is_array($args) && !empty($args)) {

      // Check if $args is a simple numeric array.
      if (range(0, count($args) - 1) === array_keys($args)) {

        // In that case, we have unnamed placeholders.
        $count = 0;
        $new_args = [];
        foreach ($args as $value) {
          if (is_float($value) || is_int($value)) {
            if (is_float($value)) {

              // Force the conversion to float so as not to loose precision
              // in the automatic cast.
              $value = sprintf('%F', $value);
            }
            $query = substr_replace($query, $value, strpos($query, '?'), 1);
          }
          else {
            $placeholder = ':db_statement_placeholder_' . $count++;
            $query = substr_replace($query, $placeholder, strpos($query, '?'), 1);
            $new_args[$placeholder] = $value;
          }
        }
        $args = $new_args;
      }
      else {

        // Else, this is using named placeholders.
        foreach ($args as $placeholder => $value) {
          if (is_float($value) || is_int($value)) {
            if (is_float($value)) {

              // Force the conversion to float so as not to loose precision
              // in the automatic cast.
              $value = sprintf('%F', $value);
            }

            // We will remove this placeholder from the query as PDO throws an
            // exception if the number of placeholders in the query and the
            // arguments does not match.
            unset($args[$placeholder]);

            // PDO allows placeholders to not be prefixed by a colon. See
            // http://marc.info/?l=php-internals&m=111234321827149&w=2 for
            // more.
            if ($placeholder[0] != ':') {
              $placeholder = ":{$placeholder}";
            }

            // When replacing the placeholders, make sure we search for the
            // exact placeholder. For example, if searching for
            // ':db_placeholder_1', do not replace ':db_placeholder_11'.
            $query = preg_replace('/' . preg_quote($placeholder) . '\\b/', $value, $query);
          }
        }
      }
    }
    return $this->pdoConnection
      ->prepare($query);
  }

  /**
   * {@inheritdoc}
   */
  public function execute($args = [], $options = []) {
    try {
      $return = parent::execute($args, $options);
    } catch (\PDOException $e) {
      if (!empty($e->errorInfo[1]) && $e->errorInfo[1] === 17) {

        // The schema has changed. SQLite specifies that we must resend the query.
        $return = parent::execute($args, $options);
      }
      else {

        // Rethrow the exception.
        throw $e;
      }
    }

    // In some weird cases, SQLite will prefix some column names by the name
    // of the table. We post-process the data, by renaming the column names
    // using the same convention as MySQL and PostgreSQL.
    $rename_columns = [];
    foreach ($this->columnNames as $k => $column) {

      // In some SQLite versions, SELECT DISTINCT(field) will return "(field)"
      // instead of "field".
      if (preg_match("/^\\((.*)\\)\$/", $column, $matches)) {
        $rename_columns[$column] = $matches[1];
        $this->columnNames[$k] = $matches[1];
        $column = $matches[1];
      }

      // Remove "table." prefixes.
      if (preg_match("/^.*\\.(.*)\$/", $column, $matches)) {
        $rename_columns[$column] = $matches[1];
        $this->columnNames[$k] = $matches[1];
      }
    }
    if ($rename_columns) {

      // DatabaseStatementPrefetch already extracted the first row,
      // put it back into the result set.
      if (isset($this->currentRow)) {
        $this->data[0] =& $this->currentRow;
      }

      // Then rename all the columns across the result set.
      foreach ($this->data as $k => $row) {
        foreach ($rename_columns as $old_column => $new_column) {
          $this->data[$k][$new_column] = $this->data[$k][$old_column];
          unset($this->data[$k][$old_column]);
        }
      }

      // Finally, extract the first row again.
      $this->currentRow = $this->data[0];
      unset($this->data[0]);
    }
    return $return;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Statement::execute	public	function	Executes a prepared statement Overrides StatementPrefetch::execute
Statement::getStatement	protected	function	The PDO SQLite layer doesn't replace numeric placeholders in queries correctly, and this makes numeric expressions (such as COUNT(*) >= :count) fail. We replace numeric placeholders in the query ourselves to work around this bug. Overrides StatementPrefetch::getStatement
StatementPrefetch::$allowRowCount	public	property	Is rowCount() execution allowed.
StatementPrefetch::$columnNames	protected	property	The list of column names in this result set.
StatementPrefetch::$currentKey	protected	property	The key of the current row.
StatementPrefetch::$currentRow	protected	property	The current row, retrieved in \PDO::FETCH_ASSOC format.
StatementPrefetch::$data	protected	property	Main data store.
StatementPrefetch::$dbh	public	property	Reference to the Drupal database connection object for this statement.
StatementPrefetch::$defaultFetchOptions	protected	property	Holds supplementary default fetch options.
StatementPrefetch::$defaultFetchStyle	protected	property	Holds the default fetch style.
StatementPrefetch::$driverOptions	protected	property	Driver-specific options. Can be used by child classes.
StatementPrefetch::$fetchOptions	protected	property	Holds supplementary current fetch options (which will be used by the next fetch).
StatementPrefetch::$fetchStyle	protected	property	Holds the current fetch style (which will be used by the next fetch).
StatementPrefetch::$pdoConnection	protected	property	Reference to the PDO connection object for this statement.
StatementPrefetch::$queryString	protected	property	The query string.
StatementPrefetch::$resultRowCount	protected	property	The number of rows in this result set.
StatementPrefetch::$rowCount	protected	property	The number of rows affected by the last query.
StatementPrefetch::current	public	function	Return the current row formatted according to the current fetch style.
StatementPrefetch::fetch	public	function	Fetches the next row from a result set. Overrides StatementInterface::fetch
StatementPrefetch::fetchAll	public	function	Returns an array containing all of the result set rows. Overrides StatementInterface::fetchAll
StatementPrefetch::fetchAllAssoc	public	function	Returns the result set as an associative array keyed by the given field. Overrides StatementInterface::fetchAllAssoc
StatementPrefetch::fetchAllKeyed	public	function	Returns the entire result set as a single associative array. Overrides StatementInterface::fetchAllKeyed
StatementPrefetch::fetchAssoc	public	function	Fetches the next row and returns it as an associative array. Overrides StatementInterface::fetchAssoc
StatementPrefetch::fetchCol	public	function	Returns an entire single column of a result set as an indexed array. Overrides StatementInterface::fetchCol
StatementPrefetch::fetchColumn	public	function
StatementPrefetch::fetchField	public	function	Returns a single field from the next record of a result set. Overrides StatementInterface::fetchField
StatementPrefetch::fetchObject	public	function	Fetches the next row and returns it as an object. Overrides StatementInterface::fetchObject
StatementPrefetch::getQueryString	public	function	Gets the query string of this statement. Overrides StatementInterface::getQueryString
StatementPrefetch::key	public	function
StatementPrefetch::next	public	function
StatementPrefetch::rewind	public	function
StatementPrefetch::rowCount	public	function	Returns the number of rows affected by the last SQL statement. Overrides StatementInterface::rowCount
StatementPrefetch::setFetchMode	public	function	Sets the default fetch mode for this statement. Overrides StatementInterface::setFetchMode
StatementPrefetch::throwPDOException	protected	function	Throw a PDO Exception based on the last PDO error.
StatementPrefetch::valid	public	function
StatementPrefetch::__construct	public	function