Delete.php

1. 8.x drupal/core/lib/Drupal/Core/Database/Query/Delete.php
2. 8.x drupal/core/lib/Drupal/Core/Database/Driver/sqlite/Delete.php
3. 8.x drupal/core/lib/Drupal/Core/Database/Driver/mysql/Delete.php
4. 8.x drupal/core/lib/Drupal/Core/Database/Driver/pgsql/Delete.php

<?php

/**
 * @file
 * Definition of Drupal\Core\Database\Driver\sqlite\Delete
 */
namespace Drupal\Core\Database\Driver\sqlite;

use Drupal\Core\Database\Query\Delete as QueryDelete;

/**
 * SQLite specific implementation of DeleteQuery.
 *
 * When the WHERE is omitted from a DELETE statement and the table being deleted
 * has no triggers, SQLite uses an optimization to erase the entire table content
 * without having to visit each row of the table individually.
 *
 * Prior to SQLite 3.6.5, SQLite does not return the actual number of rows deleted
 * by that optimized "truncate" optimization.
 */
class Delete extends QueryDelete {
  public function execute() {
    if (!count($this->condition)) {
      $total_rows = $this->connection
        ->query('SELECT COUNT(*) FROM {' . $this->connection
        ->escapeTable($this->table) . '}')
        ->fetchField();
      parent::execute();
      return $total_rows;
    }
    else {
      return parent::execute();
    }
  }

}