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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  /**
  18   * An object that contains sql join fragments.
  19   *
  20   * @since      Moodle 3.1
  21   * @package    core
  22   * @category   dml
  23   * @copyright  2016 The Open University
  24   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25   */
  26  
  27  namespace core\dml;
  28  
  29  defined('MOODLE_INTERNAL') || die();
  30  
  31  /**
  32   * An object that contains sql join fragments.
  33   *
  34   * An example of how to use this class in a simple query, where you have got
  35   * a join that is a join to the user table:
  36   *
  37   * $users = $DB->get_records_sql("SELECT u.*
  38   *         FROM {user} u
  39   *         {$sqljoin->joins}
  40   *         WHERE {$sqljoin->wheres}", $sqljoin->params);
  41   *
  42   * @since      Moodle 3.1
  43   * @package    core
  44   * @category   dml
  45   * @copyright  2016 The Open University
  46   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  47   */
  48  class sql_join {
  49  
  50      /**
  51       * @var string joins.
  52       */
  53      public $joins;
  54  
  55      /**
  56       * @var string wheres.
  57       */
  58      public $wheres;
  59  
  60      /**
  61       * @var array params.
  62       */
  63      public $params;
  64  
  65      /**
  66       * @var bool if true this join is guaranteed to never match any rows.
  67       *      In this case, the calling code may be able to completely
  68       *      skip doing the database query.
  69       * @since Moodle 3.9/3.8.3/3.7.6.
  70       */
  71      public $cannotmatchanyrows;
  72  
  73      /**
  74       * Create an object that contains sql join fragments.
  75       *
  76       * Note, even if you set $cannotmatchanyrows to true, it is
  77       * important to also set the other fields because the calling
  78       * code is not required to check it. For example
  79       * new \core\dml\sql_join('', '1 = 2', [], true);
  80       *
  81       * @param string $joins The join sql fragment.
  82       * @param string $wheres The where sql fragment.
  83       * @param array $params Any parameter values.
  84       * @param bool $cannotmatchanyrows If true, this join is guaranteed to match no rows. See comment on the field above.
  85       */
  86      public function __construct($joins = '', $wheres = '', $params = array(), $cannotmatchanyrows = false) {
  87          $this->joins = $joins;
  88          $this->wheres = $wheres;
  89          $this->params = $params;
  90          $this->cannotmatchanyrows = $cannotmatchanyrows;
  91      }
  92  }