File Source for exerciselink.class.php

<?php
/**
* Defines a gradebook ExerciseLink object.
* @author Bert Stepp�
* @package dokeos.gradebook
*/
class ExerciseLink extends AbstractLink
{
// INTERNAL VARIABLES
private $course_info = null;
private $exercise_table = null;
private $exercise_data = null;
// CONSTRUCTORS
function ExerciseLink()
{
$this->set_type(LINK_EXERCISE);
}
// FUNCTIONS IMPLEMENTING ABSTRACTLINK
/**
* Generate an array of exercises that a teacher hasn't created a link for.
* @return array 2-dimensional array - every element contains 2 subelements (id, name)
*/
public function get_not_created_links()
{
if (empty($this->course_code))
die('Error in get_not_created_links() : course code not set');
$tbl_grade_links = Database :: get_main_table(TABLE_MAIN_GRADEBOOK_LINK);
$sql = 'SELECT id,title from '.$this->get_exercise_table()
.' WHERE id NOT IN'
.' (SELECT ref_id FROM '.$tbl_grade_links
.' WHERE type = '.LINK_EXERCISE
." AND course_code = '".$this->get_course_code()."'"
.')';
$result = api_sql_query($sql, __FILE__, __LINE__);
$cats=array();
while ($data=mysql_fetch_array($result))
{
$cats[] = array ($data['id'], $data['title']);
}
return $cats;
}
/**
* Generate an array of all exercises available.
* @return array 2-dimensional array - every element contains 2 subelements (id, name)
*/
public function get_all_links()
{
if (empty($this->course_code))
die('Error in get_not_created_links() : course code not set');
$course_info = api_get_course_info($this->course_code);
$tbl_grade_links = Database :: get_main_table(TABLE_MAIN_GRADEBOOK_LINK,$course_info['dbName']);
$sql = 'SELECT id,title from '.$this->get_exercise_table();
$result = api_sql_query($sql, __FILE__, __LINE__);
$cats=array();
while ($data=mysql_fetch_array($result))
{
$cats[] = array ($data['id'], $data['title']);
}
return $cats;
}
/**
* Has anyone done this exercise yet ?
*/
public function has_results()
{
$tbl_stats = Database::get_statistic_table(TABLE_STATISTIC_TRACK_E_EXERCICES);
$sql = 'SELECT count(exe_id) AS number FROM '.$tbl_stats
." WHERE exe_cours_id = '".$this->get_course_code()."'"
.' AND exe_exo_id = '.$this->get_ref_id();
$result = api_sql_query($sql, __FILE__, __LINE__);
$number=mysql_fetch_row($result);
return ($number[0] != 0);
}
/**
* Get the score of this exercise. Only the first attempts are taken into account.
* @param $stud_id student id (default: all students who have results - then the average is returned)
* @return array (score, max) if student is given
* array (sum of scores, number of scores) otherwise
* or null if no scores available
*/
public function calc_score($stud_id = null)
{
$tbl_stats = Database::get_statistic_table(TABLE_STATISTIC_TRACK_E_EXERCICES);
$sql = 'SELECT * FROM '.$tbl_stats
." WHERE exe_cours_id = '".$this->get_course_code()."'"
.' AND exe_exo_id = '.$this->get_ref_id();
if (isset($stud_id))
$sql .= ' AND exe_user_id = '.$stud_id;
// order by id, that way the student's first attempt is accessed first
$sql .= ' ORDER BY exe_id';
$scores = api_sql_query($sql, __FILE__, __LINE__);
// for 1 student
if (isset($stud_id))
{
if ($data=mysql_fetch_array($scores))
return array ($data['exe_result'], $data['exe_weighting']);
else
return null;
}
// all students -> get average
else
{
$students=array(); // user list, needed to make sure we only
// take first attempts into account
$rescount = 0;
$sum = 0;
while ($data=mysql_fetch_array($scores))
{
if (!(array_key_exists($data['exe_user_id'],$students)))
{
if ($data['exe_weighting'] != 0)
{
$students[$data['exe_user_id']] = $data['exe_result'];
$rescount++;
$sum += ($data['exe_result'] / $data['exe_weighting']);
}
}
}
if ($rescount == 0)
return null;
else
return array ($sum , $rescount);
}
}
/**
* Get URL where to go to if the user clicks on the link.
* First we go to exercise_jump.php and then to the result page.
* Check this php file for more info.
*/
public function get_link()
{
$url = api_get_path(WEB_PATH)
.'main/gradebook/exercise_jump.php?cid='.$this->get_course_code();
if (!api_is_allowed_to_create_course()
&& $this->calc_score(api_get_user_id()) == null)
$url .= '&doexercise='.$this->get_ref_id();
return $url;
}
/**
* Get name to display: same as exercise title
*/
public function get_name()
{
$data = $this->get_exercise_data();
return $data['title'];
}
/**
* Get description to display: same as exercise description
*/
public function get_description()
{
$data = $this->get_exercise_data();
return $data['description'];
}
/**
* Check if this still links to an exercise
*/
public function is_valid_link()
{
$sql = 'SELECT count(id) from '.$this->get_exercise_table()
.' WHERE id = '.$this->get_ref_id();
$result = api_sql_query($sql, __FILE__, __LINE__);
$number=mysql_fetch_row($result);
return ($number[0] != 0);
}
public function get_type_name()
{
return get_lang('DokeosExercises');
}
public function needs_name_and_description()
{
return false;
}
public function needs_max()
{
return false;
}
public function needs_results()
{
return false;
}
public function is_allowed_to_change_name()
{
return false;
}
// INTERNAL FUNCTIONS
/**
* Lazy load function to get the database table of the exercise
*/
private function get_exercise_table ()
{
if (!isset($this->exercise_table))
{
$course_info = Database :: get_course_info($this->get_course_code());
$database_name = $course_info['db_name'];
$this->exercise_table = Database :: get_course_table(TABLE_QUIZ_TEST, $database_name);
}
return $this->exercise_table;
}
/**
* Lazy load function to get the database contents of this exercise
*/
private function get_exercise_data()
{
if (!isset($this->exercise_data))
{
$sql = 'SELECT * from '.$this->get_exercise_table()
.' WHERE id = '.$this->get_ref_id();
$result = api_sql_query($sql, __FILE__, __LINE__);
$this->exercise_data=mysql_fetch_array($result);
}
return $this->exercise_data;
}
}
?>

Source for file exerciselink.class.php