class.ilCourseObjectiveQuestion.php

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<?php
/*
        +-----------------------------------------------------------------------------+
        | ILIAS open source                                                           |
        +-----------------------------------------------------------------------------+
        | Copyright (c) 1998-2001 ILIAS open source, University of Cologne            |
        |                                                                             |
        | This program is free software; you can redistribute it and/or               |
        | modify it under the terms of the GNU General Public License                 |
        | as published by the Free Software Foundation; either version 2              |
        | of the License, or (at your option) any later version.                      |
        |                                                                             |
        | This program is distributed in the hope that it will be useful,             |
        | but WITHOUT ANY WARRANTY; without even the implied warranty of              |
        | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               |
        | GNU General Public License for more details.                                |
        |                                                                             |
        | You should have received a copy of the GNU General Public License           |
        | along with this program; if not, write to the Free Software                 |
        | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA. |
        +-----------------------------------------------------------------------------+
*/


class ilCourseObjectiveQuestion
{
        const TYPE_SELF_ASSESSMENT = 0;
        const TYPE_FINAL_TEST = 1;
        
        public $db = null;

        public $objective_id = null;
        public $questions;
        protected $tests = array();

        public function __construct($a_objective_id)
        {
                global $ilDB;

                $this->db = $ilDB;
        
                $this->objective_id = $a_objective_id;

                $this->__read();
        }
        
        
        public static function lookupObjectivesOfQuestion($a_qid)
        {
                global $ilDB;
                
                $query = 'SELECT objective_id FROM crs_objective_qst '.
                                'WHERE question_id = '.$ilDB->quote($a_qid,'integer');
                $res = $ilDB->query($query);
                $objectiveIds = array();
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $objectiveIds[] = $row->objective_id;
                }
                return $objectiveIds;
        }
        
        public static function _isTestAssignedToObjective($a_test_id,$a_objective_id)
        {
                global $ilDB;
                
                $query = "SELECT qst_ass_id FROM crs_objective_qst ".
                        "WHERE ref_id = ".$ilDB->quote($a_test_id ,'integer')." ".
                        "AND objective_id = ".$ilDB->quote($a_objective_id ,'integer');
                $res = $ilDB->query($query);
                return $res->numRows() ? true : false;
        }
        
        public function cloneDependencies($a_new_objective,$a_copy_id)
        {
                global $ilObjDataCache,$ilLog,$ilDB;
                
                include_once('Services/CopyWizard/classes/class.ilCopyWizardOptions.php');
                $cwo = ilCopyWizardOptions::_getInstance($a_copy_id);
                $mappings = $cwo->getMappings();
                foreach($this->getQuestions() as $question)
                {
                        $mapping_key = $question['ref_id'].'_question_'.$question['question_id'];
                        if(!isset($mappings[$mapping_key]) or !$mappings[$mapping_key])
                        {
                                continue;
                        }                       
                        $question_ref_id = $question['ref_id'];
                        $question_obj_id = $question['obj_id'];
                        $question_qst_id = $question['question_id'];
                        $new_ref_id = $mappings[$question_ref_id];
                        $new_obj_id = $ilObjDataCache->lookupObjId($new_ref_id);
                        
                        if($new_obj_id == $question_obj_id)
                        {
                                ilLoggerFactory::getLogger('crs')->info('Test has been linked. Keeping question id');
                                // Object has been linked
                                $new_question_id = $question_qst_id;
                        }
                        else
                        {
                                $new_question_info = $mappings[$question_ref_id.'_question_'.$question_qst_id];
                                $new_question_arr = explode('_',$new_question_info);
                                if(!isset($new_question_arr[2]) or !$new_question_arr[2])
                                {
                                        ilLoggerFactory::getLogger('crs')->debug('found invalid format of question id mapping: ' . print_r($new_question_arr,TRUE));
                                        continue;
                                }
                                $new_question_id = $new_question_arr[2];
                                ilLoggerFactory::getLogger('crs')->info('New question id is: '.$new_question_id);
                        }
        
                        ilLoggerFactory::getLogger('crs')->debug('Copying question assignments');
                        $new_question = new ilCourseObjectiveQuestion($a_new_objective);
                        $new_question->setTestRefId($new_ref_id);
                        $new_question->setTestObjId($new_obj_id);
                        $new_question->setQuestionId($new_question_id);
                        $new_question->add();
                }
                
                // Copy tests
                foreach($this->getTests() as $test)
                {
                        $new_test_id = $mappings["$test[ref_id]"];
                        
                        $query = "UPDATE crs_objective_tst ".
                                "SET tst_status = ".$this->db->quote($test['tst_status'] ,'integer').", ".
                                "tst_limit_p = ".$this->db->quote($test['tst_limit'] ,'integer')." ".
                                "WHERE objective_id = ".$this->db->quote($a_new_objective ,'integer')." ".
                                "AND ref_id = ".$this->db->quote($new_test_id ,'integer');
                        $res = $ilDB->manipulate($query);
                }
        }
        
        public static function _getAssignableTests($a_container_ref_id)
        {
                global $tree;
                
                return $tree->getSubTree($tree->getNodeData($a_container_ref_id),true,'tst');
        }

        // ########################################################  Methods for test table
        function setTestStatus($a_status)
        {
                $this->tst_status = $a_status;
        }
        function getTestStatus()
        {
                return (int) $this->tst_status;
        }
        function setTestSuggestedLimit($a_limit)
        {
                $this->tst_limit = $a_limit;
        }
        function getTestSuggestedLimit()
        {
                return (int) $this->tst_limit;
        }
        function __addTest()
        {
                global $ilDB;
                
                $query = "UPDATE crs_objective_tst ".
                        "SET tst_status = ".$this->db->quote($this->getTestStatus() ,'integer')." ".
                        "WHERE objective_id = ".$this->db->quote($this->getObjectiveId() ,'integer')." ".
                        "AND ref_id = ".$this->db->quote($this->getTestRefId() ,'integer')." ";
                $res = $ilDB->manipulate($query);
                

                // CHECK if entry already exists
                $query = "SELECT * FROM crs_objective_tst ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ".
                        "AND ref_id = ".$ilDB->quote($this->getTestRefId() ,'integer')."";

                $res = $this->db->query($query);
                if($res->numRows())
                {
                        return false;
                }
                
                // Check for existing limit
                $query = "SELECT tst_limit_p FROM crs_objective_tst ".
                        "WHERE objective_id = ".$this->db->quote($this->getObjectiveId() ,'integer')." ".
                        "AND tst_status = ".$this->db->quote($this->getTestStatus() ,'integer')." ";
                        
                $res = $this->db->query($query);
                
                $limit = 100;
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $limit = $row->tst_limit_p;
                }
                
                $next_id = $ilDB->nextId('crs_objective_tst');
                $query = "INSERT INTO crs_objective_tst (test_objective_id,objective_id,ref_id,obj_id,tst_status,tst_limit_p) ".
                        "VALUES( ".
                        $ilDB->quote($next_id,'integer').", ".
                        $ilDB->quote($this->getObjectiveId() ,'integer').", ".
                        $ilDB->quote($this->getTestRefId() ,'integer').", ".
                        $ilDB->quote($this->getTestObjId() ,'integer').", ".
                        $ilDB->quote($this->getTestStatus() ,'integer').", ".
                        $this->db->quote($limit ,'integer')." ".
                        ")";
                $res = $ilDB->manipulate($query);

                return true;
        }

        function __deleteTest($a_test_ref_id)
        {
                global $ilDB;
                
                // Delete questions
                $query = "DELETE FROM crs_objective_qst ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ".
                        "AND ref_id = ".$ilDB->quote($a_test_ref_id ,'integer')." ";
                $res = $ilDB->manipulate($query);

                // delete tst entries
                $query = "DELETE FROM crs_objective_tst ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ".
                        "AND ref_id = ".$ilDB->quote($a_test_ref_id ,'integer')." ";
                $res = $ilDB->manipulate($query);

                unset($this->tests[$a_test_ref_id]);

                return true;
        }

        public static function _updateTestLimits($a_objective_id,$a_status,$a_limit)
        {
                global $ilDB;
                
                $query = "UPDATE crs_objective_tst ".
                        "SET tst_limit_p = ".$ilDB->quote($a_limit ,'integer')." ".
                        "WHERE tst_status = ".$ilDB->quote($a_status ,'integer')." ".
                        "AND objective_id = ".$ilDB->quote($a_objective_id ,'integer');
                $res = $ilDB->manipulate($query);
                return true;
        }

        function updateTest($a_objective_id)
        {
                global $ilDB;
                
                $query = "UPDATE crs_objective_tst ".
                        "SET tst_status = ".$ilDB->quote($this->getTestStatus() ,'integer').", ".
                        "tst_limit_p = ".$ilDB->quote($this->getTestSuggestedLimit() ,'integer')." ".
                        "WHERE test_objective_id = ".$ilDB->quote($a_objective_id ,'integer')."";
                $res = $ilDB->manipulate($query);

                return true;
        }

        function getTests()
        {
                global $ilDB;
                
                $query = "SELECT * FROM crs_objective_tst cot ".
                        "JOIN object_data obd ON cot.obj_id = obd.obj_id ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ".
                        "ORDER BY title ";

                $res = $this->db->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $test['test_objective_id'] = $row->test_objective_id;
                        $test['objective_id']           = $row->objective_id;
                        $test['ref_id']                 = $row->ref_id;
                        $test['obj_id']                 = $row->obj_id;
                        $test['tst_status']             = $row->tst_status;
                        $test['tst_limit']              = $row->tst_limit_p;
                        $test['title']                  = $row->title;

                        $tests[] = $test;
                }

                return $tests ? $tests : array();
        }
        
        public function getSelfAssessmentTests()
        {
                foreach($this->tests as $test)
                {
                        if($test['status'] == self::TYPE_SELF_ASSESSMENT)
                        {
                                $self[] = $test;
                        }
                }
                return $self ? $self : array();
        }
        
        public function getFinalTests()
        {
                foreach($this->tests as $test)
                {
                        if($test['status'] == self::TYPE_FINAL_TEST)
                        {
                                $final[] = $test;
                        }
                }
                return $final ? $final : array();
        }
        
        public static function _getTest($a_test_objective_id)
        {
                global $ilDB;

                $query = "SELECT * FROM crs_objective_tst ".
                        "WHERE test_objective_id = ".$ilDB->quote($a_test_objective_id ,'integer')." ";

                $res = $ilDB->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $test['test_objective_id'] = $row->test_objective_id;
                        $test['objective_id']           = $row->objective_id;
                        $test['ref_id']                 = $row->ref_id;
                        $test['obj_id']                 = $row->obj_id;
                        $test['tst_status']             = $row->tst_status;
                        $test['tst_limit']              = $row->tst_limit_p;
                }

                return $test ? $test : array();
        }

        // ############################################################# METHODS for question table
        function getQuestions()
        {
                return $this->questions ? $this->questions : array();
        }
        
        public function getSelfAssessmentQuestions()
        {
                foreach($this->questions as $question)
                {
                        if($question['test_type'] == self::TYPE_SELF_ASSESSMENT)
                        {
                                $self[] = $question; 
                        }
                }
                return $self ? $self : array();
        }

        public function getSelfAssessmentPoints()
        {
                foreach($this->getSelfAssessmentQuestions() as $question)
                {
                        $points += $question['points'];
                }
                return $points ? $points : 0;
        }
        
        public function getFinalTestPoints()
        {
                foreach($this->getFinalTestQuestions() as $question)
                {
                        $points += $question['points'];
                }
                return $points ? $points : 0;
        }
        
        public function isSelfAssessmentQuestion($a_question_id)
        {
                foreach($this->questions as $question)
                {
                        if($question['question_id'] == $a_question_id)
                        {
                                return $question['test_type'] == self::TYPE_SELF_ASSESSMENT;
                        }
                }
                return false;
        }
        
        public function isFinalTestQuestion($a_question_id)
        {
                foreach($this->questions as $question)
                {
                        if($question['question_id'] == $a_question_id)
                        {
                                return $question['test_type'] == self::TYPE_FINAL_TEST;
                        }
                }
                return false;
                
        }
        
        public function getFinalTestQuestions()
        {
                foreach($this->questions as $question)
                {
                        if($question['test_type'] == self::TYPE_FINAL_TEST)
                        {
                                $final[] = $question; 
                        }
                }
                return $final ? $final : array();
        }
        
        
        
        public function getQuestionsOfTest($a_test_id)
        {
                foreach($this->getQuestions() as $qst)
                {
                        if($a_test_id == $qst['obj_id'])
                        {
                                $questions[] = $qst;
                        }
                }
                return $questions ? $questions : array();
        }
        
        function getQuestion($question_id)
        {
                return $this->questions[$question_id] ? $this->questions[$question_id] : array();
        }

        function getObjectiveId()
        {
                return $this->objective_id;
        }

        function setTestRefId($a_ref_id)
        {
                $this->tst_ref_id = $a_ref_id;
        }
        function getTestRefId()
        {
                return $this->tst_ref_id ? $this->tst_ref_id : 0;
        }
        function setTestObjId($a_obj_id)
        {
                $this->tst_obj_id = $a_obj_id;
        }
        function getTestObjId()
        {
                return $this->tst_obj_id ? $this->tst_obj_id : 0;
        }
        function setQuestionId($a_question_id)
        {
                $this->question_id = $a_question_id;
        }
        function getQuestionId()
        {
                return $this->question_id;
        }


        function getMaxPointsByObjective()
        {
                include_once './Modules/Test/classes/class.ilObjTest.php';

                $points = 0;
                foreach($this->getQuestions() as $question)
                {
                        $tmp_test =& ilObjectFactory::getInstanceByRefId($question['ref_id']);

                        $tmp_question =& ilObjTest::_instanciateQuestion($question['question_id']);

                        $points += $tmp_question->getMaximumPoints();

                        unset($tmp_question);
                        unset($tmp_test);
                }
                return $points;
        }
        
        function getMaxPointsByTest($a_test_ref_id)
        {
                $points = 0;

                $tmp_test =& ilObjectFactory::getInstanceByRefId($a_test_ref_id);

                foreach($this->getQuestions() as $question)
                {
                        if($question['ref_id'] == $a_test_ref_id)
                        {
                                $tmp_question =& ilObjTest::_instanciateQuestion($question['question_id']);

                                $points += $tmp_question->getMaximumPoints();

                                unset($tmp_question);
                        }
                }
                unset($tmp_test);

                return $points;
        }
        
        public static function _lookupMaximumPointsOfQuestion($a_question_id)
        {
                include_once('Modules/TestQuestionPool/classes/class.assQuestion.php');
                return assQuestion::_getMaximumPoints($a_question_id);
        }
        

        function getNumberOfQuestionsByTest($a_test_ref_id)
        {
                $counter = 0;

                foreach($this->getQuestions() as $question)
                {
                        if($question['ref_id'] == $a_test_ref_id)
                        {
                                ++$counter;
                        }
                }
                return $counter;
        }

        function getQuestionsByTest($a_test_ref_id)
        {
                foreach($this->getQuestions() as $question)
                {
                        if($question['ref_id'] == $a_test_ref_id)
                        {
                                $qst[] = $question['question_id'];
                        }
                }
                return $qst ? $qst : array();
        }

        public function updateLimits()
        {
                global $ilDB;
                
                foreach($this->tests as $ref_id => $test_data)
                {
                        switch($test_data['status'])
                        {
                                case self::TYPE_SELF_ASSESSMENT:
                                        $points = $this->getSelfAssessmentPoints();
                                        break;
                                
                                case self::TYPE_FINAL_TEST:
                                        $points = $this->getFinalTestPoints();
                                        break;
                        }
                        if($test_data['limit'] == -1 or $test_data['limit'] > $points)
                        {
                                switch($test_data['status'])
                                {
                                        case self::TYPE_SELF_ASSESSMENT:
                                                $points = $this->getSelfAssessmentPoints();
                                                break;
                                        
                                        case self::TYPE_FINAL_TEST:
                                                $points = $this->getFinalTestPoints();
                                                break;
                                }
                                $query = "UPDATE crs_objective_tst ".
                                        "SET tst_limit = ".$this->db->quote($points ,'integer')." ".
                                        "WHERE test_objective_id = ".$this->db->quote($test_data['test_objective_id'] ,'integer')." ";
                                $res = $ilDB->manipulate($query);
                        }
                }
        }


        function add()
        {
                global $ilDB;
                
                $query = "DELETE FROM crs_objective_qst ".
                        "WHERE objective_id = ".$this->db->quote($this->getObjectiveId() ,'integer')." ".
                        "AND question_id = ".$this->db->quote($this->getQuestionId() ,'integer')." ";
                $res = $ilDB->manipulate($query);
                
                $next_id = $ilDB->nextId('crs_objective_qst');
                $query = "INSERT INTO crs_objective_qst (qst_ass_id, objective_id,ref_id,obj_id,question_id) ".
                        "VALUES( ".
                        $ilDB->quote($next_id,'integer').", ".
                        $ilDB->quote($this->getObjectiveId() ,'integer').", ".
                        $ilDB->quote($this->getTestRefId() ,'integer').", ".
                        $ilDB->quote($this->getTestObjId() ,'integer').", ".
                        $ilDB->quote($this->getQuestionId() ,'integer').
                        ")";
                $res = $ilDB->manipulate($query);

                $this->__addTest();
                
                $this->__read();

                return true;
        }
        function delete($qst_id)
        {
                global $ilDB;
                
                if(!$qst_id)
                {
                        return false;
                }
                
                $query = "SELECT * FROM crs_objective_qst ".
                        "WHERE qst_ass_id = ".$ilDB->quote($qst_id ,'integer')." ";

                $res = $this->db->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $test_rid = $row->ref_id;
                        $test_oid = $row->obj_id;
                }

                $query = "DELETE FROM crs_objective_qst ".
                        "WHERE qst_ass_id = ".$ilDB->quote($qst_id ,'integer')." ";
                $res = $ilDB->manipulate($query);

                // delete test if it was the last question
                $query = "SELECT * FROM crs_objective_qst ".
                        "WHERE ref_id = ".$ilDB->quote($test_rid ,'integer')." ".
                        "AND obj_id = ".$ilDB->quote($test_oid ,'integer')." ".
                        "AND objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ";

                $res = $this->db->query($query);
                if(!$res->numRows())
                {
                        $this->__deleteTest($test_rid);
                }

                return true;
        }
        
        // begin-patch lok
        public static function deleteTest($a_tst_ref_id) 
        {
                global $ilDB;
                
                $query = 'DELETE FROM crs_objective_tst '.
                                'WHERE ref_id = '.$ilDB->quote($a_tst_ref_id,'integer');
                $ilDB->manipulate($query);

                $query = 'DELETE FROM crs_objective_qst '.
                                'WHERE ref_id = '.$ilDB->quote($a_tst_ref_id,'integer');
                $ilDB->manipulate($query);
        }
        
        
        public function deleteByTestType($a_type)
        {
                global $ilDB;
                
                
                // Read tests by type
                $deletable_refs = array();
                foreach((array) $this->tests as $tst_data)
                {
                        if($tst_data['status'] == $a_type)
                        {
                                $deletable_refs[] = $tst_data['ref_id'];
                        }
                }
                
                $query = 'DELETE from crs_objective_tst '.
                                'WHERE objective_id = '.$ilDB->quote($this->getObjectiveId(),'integer').' '.
                                'AND tst_status = '.$ilDB->quote($a_type,'integer');
                $ilDB->manipulate($query);
                
                
                $query = 'DELETE from crs_objective_tst '.
                                'WHERE objective_id = '.$ilDB->quote($this->getObjectiveId(),'integer').' '.
                                'AND '.$ilDB->in('ref_id',$deletable_refs,false,'integer');
                $ilDB->manipulate($query);
                
                return true;
        }
        // end-patch lok
        

        function deleteAll()
        {
                global $ilDB;
                
                $query = "DELETE FROM crs_objective_qst ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ";
                $res = $ilDB->manipulate($query);

                $query = "DELETE FROM crs_objective_tst ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ";
                $res = $ilDB->manipulate($query);

                return true;
        }


        // PRIVATE
        function __read()
        {
                global $ilDB,$tree;
                
                include_once './Modules/Test/classes/class.ilObjTest.php';
                include_once('Modules/Course/classes/class.ilCourseObjective.php');

                $container_ref_ids = ilObject::_getAllReferences(ilCourseObjective::_lookupContainerIdByObjectiveId($this->objective_id));
                $container_ref_id  = current($container_ref_ids);
                
                // Read test data
                $query = "SELECT * FROM crs_objective_tst ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ";
                $res = $this->db->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $this->tests[$row->ref_id]['test_objective_id'] = $row->test_objective_id;
                        $this->tests[$row->ref_id]['ref_id'] = $row->ref_id;
                        $this->tests[$row->ref_id]['obj_id'] = $row->obj_id;
                        $this->tests[$row->ref_id]['status'] = $row->tst_status;
                        $this->tests[$row->ref_id]['limit'] = $row->tst_limit_p;
                }

                $this->questions = array();
                $query = "SELECT * FROM crs_objective_qst coq ".
                        "JOIN qpl_questions qq ON coq.question_id = qq.question_id ".
                        "WHERE objective_id = ".$ilDB->quote($this->getObjectiveId() ,'integer')." ".
                        "ORDER BY title";

                $res = $this->db->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        if(!$tree->isInTree($row->ref_id) or !$tree->isGrandChild($container_ref_id,$row->ref_id))
                        {
                                $this->__deleteTest($row->ref_id);
                                continue;
                        }
                        if(!$question = ilObjTest::_instanciateQuestion($row->question_id))
                        {
                                $this->delete($row->question_id);
                                continue;
                        }
        
                        $qst['ref_id'] = $row->ref_id;
                        $qst['obj_id'] = $row->obj_id;
                        $qst['question_id'] = $row->question_id;
                        $qst['qst_ass_id'] = $row->qst_ass_id;
                        $qst['title'] = $question->getTitle();
                        $qst['description'] = $question->getComment();
                        $qst['test_type'] = $this->tests[$row->ref_id]['status'];
                        $qst['points'] = $question->getPoints();

                        $this->questions[$row->qst_ass_id] = $qst;
                }

                return true;
        }

        // STATIC
        public static function _hasTests($a_course_id)
        {
                global $ilDB;
                
                $query = "SELECT co.objective_id FROM crs_objectives co JOIN ".
                        "crs_objective_tst cot ON co.objective_id = cot.objective_id ".
                        "WHERE crs_id = ".$ilDB->quote($a_course_id ,'integer')." ";
                $res = $ilDB->query($query);
                return $res->numRows() ? true : false;
        }
        
        
        static function _isAssigned($a_objective_id,$a_tst_ref_id,$a_question_id)
        {
                global $ilDB;

                $query = "SELECT crs_qst.objective_id objective_id FROM crs_objective_qst crs_qst, crs_objectives crs_obj ".
                        "WHERE crs_qst.objective_id = crs_obj.objective_id ".
                        "AND crs_qst.objective_id = ".$ilDB->quote($a_objective_id ,'integer') ." ".
                        "AND ref_id = ".$ilDB->quote($a_tst_ref_id ,'integer')." ".
                        "AND question_id = ".$ilDB->quote($a_question_id ,'integer')." ";

                $res = $ilDB->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $objective_id = $row->objective_id;
                }
                
                return $objective_id ? $objective_id : 0;
        }
        
        // begin-patch lok
        public static function lookupQuestionsByObjective($a_test_id, $a_objective)
        {
                global $ilDB;
                
                $query = 'SELECT question_id FROM crs_objective_qst '.
                                'WHERE objective_id = '.$ilDB->quote($a_objective,'integer').' '.
                                'AND obj_id = '.$ilDB->quote($a_test_id,'integer');
                $res = $ilDB->query($query);
                
                $questions = array();
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        $questions[] = $row->question_id;
                }
                return (array) $questions;
        }
        
        public static function loookupTestLimit($a_test_id, $a_objective_id)
        {
                global $ilDB;
                
                $query = 'SELECT tst_limit_p FROM crs_objective_tst '.
                                'WHERE objective_id = '.$ilDB->quote($a_objective_id,'integer').' '.
                                'AND obj_id = '.$ilDB->quote($a_test_id,'integer');
                $res = $ilDB->query($query);
                while($row = $res->fetchRow(ilDBConstants::FETCHMODE_OBJECT))
                {
                        return (int) $row->tst_limit_p;
                }
                return 0;
        }
        
        public function toXml(ilXmlWriter $writer)
        {
                foreach($this->getTests() as $test)
                {
                        include_once './Modules/Course/classes/Objectives/class.ilLOXmlWriter.php';
                        $writer->xmlStartTag(
                                'Test',
                                array(
                                        'type' => ilLOXmlWriter::TYPE_TST_ALL,
                                        'refId' => $test['ref_id'],
                                        'testType' => $test['tst_status'],
                                        'limit' => $test['tst_limit']
                                )
                        );
                        
                        // questions
                        foreach($this->getQuestionsByTest($test['ref_id']) as $question_id)
                        {
                                $writer->xmlElement('Question', array('id' => $question_id));
                        }
                        $writer->xmlEndTag('Test');
                }
                
        }
        
        // end-patch lok

}
?>