class Select in Drupal 10

PostgreSQL implementation of \Drupal\Core\Database\Query\Select.

Hierarchy

• class \Drupal\pgsql\Driver\Database\pgsql\Select extends \Drupal\Core\Database\Query\Select

Related topics

Database abstraction layer

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

2 files declare their use of Select

Select.php in core/lib/Drupal/Core/Database/Driver/pgsql/Select.php

Select.php in core/modules/system/tests/modules/driver_test/src/Driver/Database/DrivertestPgsql/Select.php

6 string references to 'Select'

ConnectionTest::providerGetDriverClass in core/tests/Drupal/Tests/Core/Database/ConnectionTest.php

Data provider for testGetDriverClass().

ConnectionTest::testConnectionOptions in core/tests/Drupal/KernelTests/Core/Database/ConnectionTest.php

Tests the connection options of the active database.

ContentModerationConfigureForm::buildConfigurationForm in core/modules/content_moderation/src/Form/ContentModerationConfigureForm.php

Form constructor.

FilterPluginBase::buildExposedFiltersGroupForm in core/modules/views/src/Plugin/views/filter/FilterPluginBase.php

Build the form to let users create the group of exposed filters.

FormTestValidateRequiredForm::buildForm in core/modules/system/tests/modules/form_test/src/Form/FormTestValidateRequiredForm.php

Form constructor.

... See full list

File

core/modules/pgsql/src/Driver/Database/pgsql/Select.php, line 15

Namespace

Drupal\pgsql\Driver\Database\pgsql

class Select extends QuerySelect {

  /**
   * {@inheritdoc}
   */
  public function __construct(Connection $connection, $table, $alias = NULL, array $options = []) {

    // @todo Remove the __construct in Drupal 11.
    // @see https://www.drupal.org/project/drupal/issues/3256524
    parent::__construct($connection, $table, $alias, $options);
    unset($this->queryOptions['return']);
  }
  public function orderRandom() {
    $alias = $this
      ->addExpression('RANDOM()', 'random_field');
    $this
      ->orderBy($alias);
    return $this;
  }

  /**
   * Overrides SelectQuery::orderBy().
   *
   * PostgreSQL adheres strictly to the SQL-92 standard and requires that when
   * using DISTINCT or GROUP BY conditions, fields and expressions that are
   * ordered on also need to be selected. This is a best effort implementation
   * to handle the cases that can be automated by adding the field if it is not
   * yet selected.
   *
   * @code
   *   $query = \Drupal::database()->select('example', 'e');
   *   $query->join('example_revision', 'er', '[e].[vid] = [er].[vid]');
   *   $query
   *     ->distinct()
   *     ->fields('e')
   *     ->orderBy('timestamp');
   * @endcode
   *
   * In this query, it is not possible (without relying on the schema) to know
   * whether timestamp belongs to example_revision and needs to be added or
   * belongs to node and is already selected. Queries like this will need to be
   * corrected in the original query by adding an explicit call to
   * SelectQuery::addField() or SelectQuery::fields().
   *
   * Since this has a small performance impact, both by the additional
   * processing in this function and in the database that needs to return the
   * additional fields, this is done as an override instead of implementing it
   * directly in SelectQuery::orderBy().
   */
  public function orderBy($field, $direction = 'ASC') {

    // Only allow ASC and DESC, default to ASC.
    // Emulate MySQL default behavior to sort NULL values first for ascending,
    // and last for descending.
    // @see http://www.postgresql.org/docs/9.3/static/queries-order.html
    $direction = strtoupper($direction) == 'DESC' ? 'DESC NULLS LAST' : 'ASC NULLS FIRST';
    $this->order[$field] = $direction;
    if ($this
      ->hasTag('entity_query')) {
      return $this;
    }

    // If there is a table alias specified, split it up.
    if (strpos($field, '.') !== FALSE) {
      [
        $table,
        $table_field,
      ] = explode('.', $field);
    }

    // Figure out if the field has already been added.
    foreach ($this->fields as $existing_field) {
      if (!empty($table)) {

        // If table alias is given, check if field and table exists.
        if ($existing_field['table'] == $table && $existing_field['field'] == $table_field) {
          return $this;
        }
      }
      else {

        // If there is no table, simply check if the field exists as a field or
        // an aliased field.
        if ($existing_field['alias'] == $field) {
          return $this;
        }
      }
    }

    // Also check expression aliases.
    foreach ($this->expressions as $expression) {
      if ($expression['alias'] == $this->connection
        ->escapeAlias($field)) {
        return $this;
      }
    }

    // If a table loads all fields, it can not be added again. It would
    // result in an ambiguous alias error because that field would be loaded
    // twice: Once through table_alias.* and once directly. If the field
    // actually belongs to a different table, it must be added manually.
    foreach ($this->tables as $table) {
      if (!empty($table['all_fields'])) {
        return $this;
      }
    }

    // If $field contains characters which are not allowed in a field name
    // it is considered an expression, these can't be handled automatically
    // either.
    if ($this->connection
      ->escapeField($field) != $field) {
      return $this;
    }

    // This is a case that can be handled automatically, add the field.
    $this
      ->addField(NULL, $field);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function addExpression($expression, $alias = NULL, $arguments = []) {
    if (empty($alias)) {
      $alias = 'expression';
    }

    // This implements counting in the same manner as the parent method.
    $alias_candidate = $alias;
    $count = 2;
    while (!empty($this->expressions[$alias_candidate])) {
      $alias_candidate = $alias . '_' . $count++;
    }
    $alias = $alias_candidate;
    $this->expressions[$alias] = [
      'expression' => $expression,
      'alias' => $this->connection
        ->escapeAlias($alias_candidate),
      'arguments' => $arguments,
    ];
    return $alias;
  }

  /**
   * {@inheritdoc}
   */
  public function execute() {
    $this->connection
      ->addSavepoint();
    try {
      $result = parent::execute();
    } catch (\Exception $e) {
      $this->connection
        ->rollbackSavepoint();
      throw $e;
    }
    $this->connection
      ->releaseSavepoint();
    return $result;
  }

}

Members

Name	Modifiers	Type	Description	Overrides
Select::addExpression	public	function
Select::execute	public	function
Select::orderBy	public	function	Overrides SelectQuery::orderBy().
Select::orderRandom	public	function
Select::__construct	public	function