include/classes/DAO/UserCoursesDAO.class.php

   1 <?php
   2 /************************************************************************/
   3 /* AContent                                                             */
   4 /************************************************************************/
   5 /* Copyright (c) 2010                                                   */
   6 /* Inclusive Design Institute                                           */
   7 /*                                                                      */
   8 /* This program is free software. You can redistribute it and/or        */
   9 /* modify it under the terms of the GNU General Public License          */
  10 /* as published by the Free Software Foundation.                        */
  11 /************************************************************************/
  12
  13 /**
  14  * DAO for "user_courses" table
  15  * @access      public
  16  * @author      Cindy Qi Li
  17  * @package     DAO
  18  */
  19
  20 if (!defined('TR_INCLUDE_PATH')) exit;
  21
  22 require_once(TR_INCLUDE_PATH. 'classes/DAO/DAO.class.php');
  23
  24 class UserCoursesDAO extends DAO {
  25
  26         /**
  27          * Create a new row
  28          * @access  public
  29          * @param   user_id
  30          *          course_id
  31          *          last_cid
  32          * @return  true if a new row is inserted successfully or the record with (user_id, course_id) already exists
  33          *          otherwise, false
  34          * @author  Cindy Qi Li
  35          */
  36         public function Create($user_id, $course_id, $role, $last_cid)
  37         {
  38                 // check whether the record already exists
  39                 if (!$this->isExist($user_id, $course_id))
  40                 {
  41                         /* insert into the db */
  42                         $sql = "INSERT INTO ".TABLE_PREFIX."user_courses
  43                                       (user_id, course_id, role, last_cid)
  44                                VALUES (".$user_id.",
  45                                        ".$course_id.",
  46                                        ".$role.",
  47                                        ".$last_cid.")";
  48
  49                         return $this->execute($sql);
  50                 }
  51                 else
  52                 {
  53                         return true;
  54                 }
  55         }
  56
  57         /**
  58          * Update last cid based on user id and course id
  59          * @access  public
  60          * @param   user_id
  61          *          course_id
  62          *          last_cid
  63          * @return  true if successful
  64          *          otherwise, false
  65          * @author  Cindy Qi Li
  66          */
  67         public function UpdateLastCid($user_id, $course_id, $last_cid)
  68         {
  69                 // only save last cid for courses that are on the user's course list
  70                 if ($this->isExist($user_id, $course_id))
  71                 {
  72                         $sql = "UPDATE ".TABLE_PREFIX."user_courses
  73                                    SET last_cid = ".$last_cid."
  74                                  WHERE user_id = ".$user_id."
  75                                    AND course_id = ".$course_id;
  76
  77                         return $this->execute($sql);
  78                 }
  79                 else return true;
  80         }
  81
  82         /**
  83          * Delete a record
  84          * @access  public
  85          * @param   user id, course id
  86          * @return  true, if successful, otherwise, return false
  87          * @author  Cindy Qi Li
  88          */
  89         public function Delete($user_id, $course_id)
  90         {
  91                 $sql = "DELETE FROM ".TABLE_PREFIX."user_courses
  92                          WHERE user_id = ".$user_id." AND course_id = ".$course_id;
  93                 return $this->execute($sql);
  94         }
  95
  96         /**
  97          * Return course information by given user id & course_id
  98          * @access  public
  99          * @param   user id
 100          *          course_id
 101          * @return  one row from table "user_courses"
 102          * @author  Cindy Qi Li
 103          */
 104         public function get($user_id, $course_id)
 105         {
 106                 $sql = "SELECT * FROM ".TABLE_PREFIX."user_courses
 107                          WHERE user_id=".$user_id."
 108                            AND course_id = ".$course_id;
 109                 if ($rows = $this->execute($sql))
 110                 {
 111                         return $rows[0];
 112                 }
 113                 else return false;
 114         }
 115
 116         /**
 117          * Return course information by given user id
 118          * @access  public
 119          * @param   user id
 120          * @return  course row
 121          * @author  Cindy Qi Li
 122          */
 123         public function getByUserID($user_id)
 124         {
 125                 $sql = "SELECT * FROM ".TABLE_PREFIX."user_courses uc, ".TABLE_PREFIX."courses c
 126                          WHERE uc.user_id=".$user_id."
 127                            AND uc.course_id = c.course_id
 128                          ORDER BY c.title";
 129                 return $this->execute($sql);
 130         }
 131
 132         /**
 133          * Return course information by given user id
 134          * @access  public
 135          * @param   user id
 136          * @return  course row
 137          * @author  Cindy Qi Li
 138          */
 139         public function isExist($user_id, $course_id)
 140         {
 141                 $sql = "SELECT * FROM ".TABLE_PREFIX."user_courses
 142                          WHERE user_id=".$user_id."
 143                            AND course_id=".$course_id;
 144                 $rows = $this->execute($sql);
 145
 146                 return is_array($rows);
 147         }
 148
 149 }
 150 ?>