class StatementEmpty

Empty implementation of a database statement.

This class satisfies the requirements of being a database statement/result object, but does not actually contain data. It is useful when developers need to safely return an "empty" result set without connecting to an actual database. Calling code can then treat it the same as if it were an actual result set that happens to contain no records.

Hierarchy

Expanded class hierarchy of StatementEmpty

Deprecated

in drupal:9.2.0 and is removed from drupal:10.0.0. There is no replacement. Use mocked StatementInterface classes in tests if needed.

See also

\Drupal\search\SearchQuery

https://www.drupal.org/node/1234567

1 file declares its use of StatementEmpty
EmptyStatementTest.php in core/tests/Drupal/Tests/Core/Database/EmptyStatementTest.php

File

core/lib/Drupal/Core/Database/StatementEmpty.php, line 23

Namespace

Drupal\Core\Database
View on git.drupalcode.org
View source 
class StatementEmpty implements \Iterator, StatementInterface {
  
  /**
   * Is rowCount() execution allowed.
   *
   * @var bool
   */
  public $allowRowCount = FALSE;
  
  /**
   * {@inheritdoc}
   */
  public function execute($args = [], $options = []) {
    return FALSE;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getQueryString() {
    return '';
  }
  
  /**
   * {@inheritdoc}
   */
  public function rowCount() {
    if ($this->allowRowCount) {
      return 0;
    }
    throw new RowCountException();
  }
  
  /**
   * {@inheritdoc}
   */
  public function setFetchMode($mode, $a1 = NULL, $a2 = []) {
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetch($mode = NULL, $cursor_orientation = NULL, $cursor_offset = NULL) {
    return NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchField($index = 0) {
    return NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchObject(string $class_name = NULL, array $constructor_arguments = NULL) {
    return NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchAssoc() {
    return NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchAll($mode = NULL, $column_index = NULL, $constructor_arguments = NULL) {
    return [];
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchCol($index = 0) {
    return [];
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchAllKeyed($key_index = 0, $value_index = 1) {
    return [];
  }
  
  /**
   * {@inheritdoc}
   */
  public function fetchAllAssoc($key, $fetch = NULL) {
    return [];
  }
  
  /**
   * {@inheritdoc}
   */
  public function current() {
    return NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function key() {
    return NULL;
  }
  
  /**
   * {@inheritdoc}
   */
  public function rewind() {
    // Nothing to do: our DatabaseStatement can't be rewound.
  }
  
  /**
   * {@inheritdoc}
   */
  public function next() {
    // Do nothing, since this is an always-empty implementation.
  }
  
  /**
   * {@inheritdoc}
   */
  public function valid() {
    return FALSE;
  }

}

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