Source for file HarmoniGradingManager.class.php

<?php 
 
require_once(OKI2."/osid/grading/GradingManager.php");
 
 
require_once(HARMONI."oki2/grading/HarmoniGradableObject.class.php");
require_once(HARMONI."oki2/grading/HarmoniGradeRecord.class.php");
require_once(HARMONI."oki2/grading/HarmoniGradableObjectIterator.class.php");
require_once(HARMONI."oki2/grading/HarmoniGradeRecordIterator.class.php");
 
 
 
/**
 * <p>
 * GradingManager handles creating and deleting:
 * 
 * <ul>
 * <li>
 * GradableObject,
 * </li>
 * <li>
 * GradeRecord
 * </li>
 * </ul>
 * 
 * and getting:
 * 
 * <ul>
 * <li>
 * GradableObject,
 * </li>
 * <li>
 * GradeRecords,
 * </li>
 * <li>
 * various implementation Types.
 * </li>
 * </ul>
 * </p>
 * 
 * <p>
 * All implementations of OsidManager (manager) provide methods for accessing
 * and manipulating the various objects defined in the OSID package. A manager
 * defines an implementation of an OSID. All other OSID objects come either
 * directly or indirectly from the manager. New instances of the OSID objects
 * are created either directly or indirectly by the manager.  Because the OSID
 * objects are defined using interfaces, create methods must be used instead
 * of the new operator to create instances of the OSID objects. Create methods
 * are used both to instantiate and persist OSID objects.  Using the
 * OsidManager class to define an OSID's implementation allows the application
 * to change OSID implementations by changing the OsidManager package name
 * used to load an implementation. Applications developed using managers
 * permit OSID implementation substitution without changing the application
 * source code. As with all managers, use the OsidLoader to load an
 * implementation of this interface.
 * </p>
 * 
 * <p></p>
 * 
 * <p>
 * OSID Version: 2.0
 * </p>
 * 
 * <p>
 * Licensed under the {@link org.osid.SidImplementationLicenseMIT MIT}
 * O.K.I&#46; OSID Definition License}.
 * </p>
 * 
 * @package org.osid.grading
 */
class HarmoniGradingManager
    extends GradingManager
{
    
    
    
    
    
    
    /**
    * @variable object OsidContext $_osidContext the OSID context.
    * @access private
    ***/
    var $_osidContext;
 
 
 
 
 
    /**
    * @param ref object $drId A {@link HarmoniId} referencing our DR.
    */
    function HarmoniCourseManagementManager () {
 
 
    }
 
 
 
    /**
    * Assign the configuration of this Manager. There are no valid configuration options for
    * this manager.
    * 
    *
    * @param object Properties $configuration (original type: java.util.Properties)
    *
    * @throws object OsidException An exception with one of the following
    *            messages defined in org.osid.OsidException:    {@link }
    *            org.osid.OsidException#OPERATION_FAILED OPERATION_FAILED},
    *            {@link org.osid.OsidException#PERMISSION_DENIED}
    *            PERMISSION_DENIED}, {@link }
    *            org.osid.OsidException#CONFIGURATION_ERROR
    *            CONFIGURATION_ERROR}, {@link }
    *            org.osid.OsidException#UNIMPLEMENTED UNIMPLEMENTED}, {@link }
    *            org.osid.OsidException#NULL_ARGUMENT NULL_ARGUMENT}
    *
    * @access public
    */
    function assignConfiguration ( $configuration ) {
        
        
    }
 
    /**
    * Return context of this OsidManager.
    *
    * @return object OsidContext 
    *
    * @throws object OsidException
    *
    * @access public
    */
    function getOsidContext () {
        return $this->_osidContext;
    }
 
    /**
    * Assign the context of this OsidManager.
    *
    * @param object OsidContext $context 
    *
    * @throws object OsidException An exception with one of the following
    *            messages defined in org.osid.OsidException:    {@link }
    *            org.osid.OsidException#NULL_ARGUMENT NULL_ARGUMENT}
    *
    * @access public
    */
    function assignOsidContext ( $context ) {
        
        $this->_osidContext =$context;
    }
    
    
    
    
    
    
    
    
    /**
     * Create a new GradableObject which includes all the elements for grading
     * something for a CourseSection.  The type of grade and other grade
     * characteristics are also specified.
     * 
     * @param string $displayName 
     * @param string $description 
     * @param object Id $courseSectionId 
     * @param object Id $externalReferenceId 
     * @param object Type $gradeType 
     * @param object Type $scoringDefinition 
     * @param object Type $gradeScale 
     * @param int $gradeWeight 
     *  
     * @return object GradableObject 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_TYPE UNKNOWN_TYPE}
     * 
     * @access public
     */
    function createGradableObject ( $displayName, $description, $courseSectionId, $externalReferenceId, $gradeType, $scoringDefinition, $gradeScale, $gradeWeight ) { 
        //make id
        $idManager = Services::getService("IdManager");
        $id=$idManager->createId();
 
        //prepare insert query
        $dbManager= Services::getService("DatabaseManager");
        $query= new InsertQuery;
        $query->setTable('gr_gradable');
 
        //ready values
        $query->setColumns(array('id','fk_gr_scoring_type','fk_gr_grade_type','fk_gr_gradescale_type','description','name','fk_reference_id','fk_cm_section','weight'));
        $values[]="'".addslashes($id->getIdString())."'";
        $values[]="'".$this->_typeToIndex('scoring',$scoringDefinition)."'";
        $values[]="'".$this->_typeToIndex('grade',$gradeType)."'";
        $values[]="'".$this->_typeToIndex('gradescale',$gradeScale)."'";
        $values[]="'".addslashes($description)."'";
        $values[]="'".addslashes($displayName)."'";
        $values[]="'".addslashes($externalReferenceId->getIdString())."'";
        $values[]="'".addslashes($courseSectionId->getIdString())."'";
        $values[]="'".addslashes($gradeWeight)."'";
        $query->addRowOfValues($values);
 
 
        //query
        $dbManager->query($query);
 
        //make object and update
        $ret = new HarmoniGradableObject($id);
        $ret->_setModifiedDateAndAgent();
        return $ret; 
    } 
 
    /**
     * Delete a GradableObject.
     * 
     * @param object Id $gradableObjectId 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_ID UNKNOWN_ID}
     * 
     * @access public
     */
    function deleteGradableObject ( $gradableObjectId ) {
 
            
        $dbManager = Services::getService("DatabaseManager");
        
        //first delete the GradeRecords
        $query= new DeleteQuery;
        $query->setTable('gr_record');
        $where = "fk_gr_gradable='".addslashes($gradableObjectId->getIdString())."'";
        $query->addWhere($where);
        $dbManager->query($query);
        
        //next delete the GradableObject
        $query= new DeleteQuery;
        $query->setTable('gr_gradable');
        $query->addWhere("id=".addslashes($gradableObjectId->getIdString()));
        $dbManager->query($query);
    } 
 
    /**
     * Get a GradableObject by unique Id.
     * 
     * @param object Id $gradableObjectId 
     *  
     * @return object GradableObject 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_ID UNKNOWN_ID}
     * 
     * @access public
     */
    function getGradableObject ( $gradableObjectId ) { 
        $ret = new HarmoniGradableObject($gradableObjectId);     
        return $ret; 
    } 
 
    /**
     * Get all the GradableObjects, optionally including only those for a
     * specific CourseSection or External Reference to what is being graded.
     * If any parameter is null, what is returned is not filtered by that
     * parameter.
     * 
     * @param object Id $courseSectionId 
     * @param object Id $externalReferenceId 
     *  
     * @return object GradableObjectIterator 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_ID UNKNOWN_ID}
     * 
     * @access public
     */
    function getGradableObjects ( $courseSectionId, $externalReferenceId ) { 
        //set up query
        $dbManager = Services::getService("DatabaseManager");
        $query= new SelectQuery;
        $query->addTable('gr_gradable');
    
        $query->addColumn('id');
        
        
        //add appropriate wheres
        if(!is_null($courseSectionId)){
            $query->addWhere("fk_cm_section = '".addslashes($courseSectionId->getIdString())."'");        
        }
        if(!is_null($externalReferenceId)){
            $query->addWhere("fk_reference_id = '".addslashes($externalReferenceId->getIdString())."'");    
        }
    
        
        $res =$dbManager->query($query);
 
        //get results in array
        $array = array();
        $idManager=  Services::getService("IdManager");
        while($res->hasMoreRows()){
            $row = $res->getCurrentRow();
            $res->advanceRow();
            $id =$idManager->getId($row['id']);
            $array[] = new HarmoniGradableObject($id);
 
        }
        
        //convert and return
        $ret = new  HarmoniGradableObjectIterator($array);
        return $ret;
    } 
 
    /**
     * Create a new GradeRecord for an Agent and with a Grade and
     * GradeRecordType.   The GradeRecordType is they Type of GradeRecord not
     * the Type of Grade contained in it.  GradeRecord Types might indicate a
     * mid-term, partial, or final grade while GradeTypes might be letter,
     * numeric, etc.  The Agent in this context is not the person who took the
     * test nor, necessarily, the person who is grading.  It is the person
     * whose "GradeBook" this is, for example the CourseSection instructor.
     * 
     * @param object Id $gradableObjectId 
     * @param object Id $agentId 
     * @param object mixed $gradeValue (original type: java.io.Serializable)
     * @param object Type $GradeRecordType 
     *  
     * @return object GradeRecord 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_ID UNKNOWN_ID},
     *          {@link org.osid.grading.GradingException#UNKNOWN_TYPE}
     *          UNKNOWN_TYPE}
     * 
     * @access public
     */
    function createGradeRecord ( $gradableObjectId, $agentId, $gradeValue, $GradeRecordType ) { 
        //make id
        $idManager = Services::getService("IdManager");
        $id=$idManager->createId();
 
        //prepare insert query
        $dbManager= Services::getService("DatabaseManager");
        $query= new InsertQuery;
        $query->setTable('gr_record');
 
        //ready values
        $query->setColumns(array('id','value','fk_gr_gradable','fk_agent_id','fk_gr_record_type'));
        $values[]="'".addslashes($id->getIdString())."'";
        $values[]="'".addslashes($gradeValue)."'";
        $values[]="'".addslashes($gradableObjectId->getIdString())."'";
        $values[]="'".addslashes($agentId->getIdString())."'";
        $values[]="'".$this->_typeToIndex('record',$GradeRecordType)."'";
        $query->addRowOfValues($values);
 
 
        //query
        $dbManager->query($query);
 
        //make object and update
        $ret = new HarmoniGradeRecord($id);
        $ret->_setModifiedDateAndAgent();
        return $ret;  
    } 
 
    /**
     * Delete a GradeRecord.  The first two parameters are required, but the
     * third may be left null to dignify any Type
     * 
     * @param object Id $gradableObjectId 
     * @param object Id $agentId 
     * @param object Type $GradeRecordType 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_ID UNKNOWN_ID}
     * 
     * @access public
     */
    function deleteGradeRecord ( $gradableObjectId, $agentId, $GradeRecordType = null) { 
        $dbManager = Services::getService("DatabaseManager");
        $query= new DeleteQuery;
        $query->setTable('gr_record');
        $query->addWhere("fk_gr_gradable='".addslashes($gradableObjectId->getIdString())."'");
        $query->addWhere("fk_agent_id='".addslashes($agentId->getIdString())."'");
        if(!is_null($GradeRecordType)){
            $query->addWhere("fk_gr_record_type='".addslashes($this->_typeToIndex('record',$GradeRecordType))."'");
        }
        $dbManager->query($query);
    } 
 
    /**
     * Get all the GradeRecords, optionally including only those for a specific
     * CourseSection, GradableObject, External Reference to what is being
     * graded, GradeRecordType, or Agent.  If any parameter is null, what is
     * returned is not filtered by that parameter.  For example,
     * getGradeRecords(xyzCourseSectionId,null,null,null,null) returns all
     * GradeRecords for the xyzCourseSection; and
     * getGradeRecords(xyzCourseSectionId,null,null,myAgent,quizGradeRecordType)
     * returns all GradeRecords for quizzes taken by myAgent in the
     * xyzCourseSection.
     * 
     * @param object Id $courseSectionId 
     * @param object Id $externalReferenceId 
     * @param object Id $gradableObjectId 
     * @param object Id $agentId 
     * @param object Type $GradeRecordType 
     *  
     * @return object GradeRecordIterator 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED},
     *          {@link org.osid.grading.GradingException#NULL_ARGUMENT}
     *          NULL_ARGUMENT}, {@link }
     *          org.osid.grading.GradingException#UNKNOWN_ID UNKNOWN_ID},
     *          {@link org.osid.grading.GradingException#UNKNOWN_TYPE}
     *          UNKNOWN_TYPE}
     * 
     * @access public
     */
    function getGradeRecords ( $courseSectionId, $externalReferenceId, $gradableObjectId, $agentId, $GradeRecordType ) {         
        //set up query
        $dbManager = Services::getService("DatabaseManager");
        $query= new SelectQuery;
        $query->addTable('gr_record');
        
        //inner join?
        if(!is_null($externalReferenceId) || !is_null($courseSectionId)){
            $query->addTable('gr_gradable',INNER_JOIN,"gr_gradable.id=gr_record.fk_gr_gradable");
            
        }
        
        
        $query->addColumn('id','id','gr_record');
        
        
        
        
        //add appropriate wheres
        if(!is_null($courseSectionId)){
            $query->addWhere("gr_gradable.fk_cm_section = '".addslashes($courseSectionId->getIdString())."'");        
        }
        if(!is_null($externalReferenceId)){
            $query->addWhere("gr_gradable.fk_reference_id = '".addslashes($externalReferenceId->getIdString())."'");    
        }
        if(!is_null($gradableObjectId)){            
            $query->addWhere("gr_record.fk_gr_gradable = '".addslashes($gradableObjectId->getIdString())."'");
        }
        if(!is_null($agentId)){            
            $query->addWhere("gr_record.fk_agent_id='".addslashes($agentId->getIdString())."'");
        }
        if(!is_null($GradeRecordType)){            
            $query->addWhere("gr_record.fk_gr_record_type='".addslashes($this->_typeToIndex('record',$GradeRecordType))."'");
        }
        
        $res =$dbManager->query($query);
 
        //get results in array
        $array = array();
        $idManager=  Services::getService("IdManager");
        while($res->hasMoreRows()){
 
            $row = $res->getCurrentRow();
            $res->advanceRow();
            $id =$idManager->getId($row['id']);
            $array[] = new HarmoniGradeRecord($id);
 
        }
        
        //convert and return
        $ret = new  HarmoniGradeRecordIterator($array);
        return $ret;
    } 
 
    /**
     * Get all GradeRecordTypes.
     *  
     * @return object TypeIterator 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED}
     * 
     * @access public
     */
    function getGradeRecordTypes () { 
        return $this->_getTypes("record"); 
    } 
 
    /**
     * Get all GradeTypes.
     *  
     * @return object TypeIterator 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED}
     * 
     * @access public
     */
    function getGradeTypes () { 
       return $this->_getTypes("grade");
    } 
 
    /**
     * Get all ScoringDefinitions.
     *  
     * @return object TypeIterator 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED}
     * 
     * @access public
     */
    function getScoringDefinitions () { 
        return $this->_getTypes("scoring"); 
    } 
 
    /**
     * Get all GradeScales.
     *  
     * @return object TypeIterator 
     * 
     * @throws object GradingException An exception with one of the
     *          following messages defined in org.osid.grading.GradingException
     *          may be thrown:  {@link }
     *          org.osid.grading.GradingException#OPERATION_FAILED
     *          OPERATION_FAILED}, {@link }
     *          org.osid.grading.GradingException#PERMISSION_DENIED
     *          PERMISSION_DENIED}, {@link }
     *          org.osid.grading.GradingException#CONFIGURATION_ERROR
     *          CONFIGURATION_ERROR}, {@link }
     *          org.osid.grading.GradingException#UNIMPLEMENTED UNIMPLEMENTED}
     * 
     * @access public
     */
    function getGradeScales () { 
        return $this->_getTypes("gradescale");
    } 
    
    
 
     /**
     * Get all the Types from the table specified
     * 
     * @param string $typename the type of Types to get
     *  
     * @return object HarmoniTypeIterator 
     * 
     * @access private
     */
    function _getTypes($typename){
        
        //query 
        $dbHandler = Services::getService("DBHandler");
        $query= new SelectQuery;
        $query->addTable('gr_'.$typename."_type");
        $query->addColumn('domain');
        $query->addColumn('authority');
        $query->addColumn('keyword');
        $query->addColumn('description');
        $res=$dbHandler->query($query);
        
        //iterate through results and add to an array
        $array=array();        
        while($res->hasMoreRows()){
            $row = $res->getCurrentRow();
            $res->advanceRow();
            if(is_null($row['description'])){
                $the_type = new Type($row['domain'],$row['authority'],$row['keyword']);
            }else{
                $the_type = new Type($row['domain'],$row['authority'],$row['keyword'],$row['description']);
            }
            $array[] = $the_type;
        }
        
        //convert to an iterator
        $ret = new HarmoniTypeIterator($array);
        return $ret;
    }
 
     /**
    * For object in table $table with id $id, get the Type with type $typename
    *
    * @param object Id $id the Id of the object in question
    * @param string $table the table our object resides in
    * @param string $typename the type of Type to get
    *
    * @return object Type 
    *
    * @access private
    */
    function _getType($id, $table, $typename){
        //the appropriate table names and fields must be given names according to the pattern indicated below
 
        //get the index for the type
        $index = $this->_getField($id,$table,"fk_gr_".$typename."_type");
 
        
        return $this->_indexToType($index,$typename);
 
    }
    
    
    /**
    * For get the Type with type $typename with id $index
    *
    * @param string $index the index of the type
    * @param string $typename the type of Type to get
    *
    * @return object Type 
    *
    * @access private
    */
    function _indexToType($index, $typename){
        //the appropriate table names and fields must be given names according to the pattern indicated below
 
        //query
        $dbHandler = Services::getService("DBHandler");
        $query= new SelectQuery;
        $query->addTable('gr_'.$typename."_type");
        $query->addWhere("id=".$index);
        $query->addColumn('domain');
        $query->addColumn('authority');
        $query->addColumn('keyword');
        $query->addColumn('description');
        $res=$dbHandler->query($query);
 
 
        if(!$res->hasMoreRows()){
            throwError(new Error("No Type has Id '".$index."' in table 'gr_".$typename."_type'","CourseManagement", true));
        }
 
        //There should be exactly one result.  Convert it to a type and return it
        //remember that the description is optional
        $row = $res->getCurrentRow();
        if(is_null($row['description'])){
            $the_type = new Type($row['domain'],$row['authority'],$row['keyword']);
        }else{
            $the_type = new Type($row['domain'],$row['authority'],$row['keyword'],$row['description']);
        }
        return $the_type;
 
    }
 
    /**
     * Find the index for our Type of type $type in its table.  If it is not there,
     * put it into the table and return the index.
     *    
     * @param string $typename the type of Type that is passed in.
     * @param object Type $type the Type itself
     * 
     * @return object Type 
     * 
     * @access private
     */
    function _typeToIndex($typename, $type){
        //the appropriate table names and fields must be given names according to the pattern indicated below
 
        //validate the Type
        ArgumentValidator::validate($type, ExtendsValidatorRule::getRule("Type"), true);
        
        //query to see if it exists
        $dbHandler = Services::getService("DBHandler");
        $query= new SelectQuery;
        $query->addTable('gr_'.$typename."_type");
        $query->addWhere("domain='".$type->getDomain()."'");
        $query->addWhere("authority='".$type->getAuthority()."'");
        $query->addWhere("keyword='".$type->getKeyword()."'");
        $query->addColumn('id');
        $res=$dbHandler->query($query);
 
 
        
        if($res->getNumberOfRows()==0){
            //if not query to create it
            $query= new InsertQuery;
            $query->setTable('gr_'.$typename.'_type');
            $values[]="'".addslashes($type->getDomain())."'";
            $values[]="'".addslashes($type->getAuthority())."'";
            $values[]="'".addslashes($type->getKeyword())."'";
            if(is_null($type->getDescription())){
                $query->setColumns(array('domain','authority','keyword'));
            }else{
                $query->setColumns(array('domain','authority','keyword','description'));
                $values[]="'".addslashes($type->getDescription())."'";
            }
 
            $query->addRowOfValues($values);
            $query->setAutoIncrementColumn('id', 'gr_'.$typename.'_type_id_sequence');
 
 
            $result =$dbHandler->query($query);
 
            return $result->getLastAutoIncrementValue();
        }elseif($res->getNumberOfRows()==1){
            //if it does exist, create it
            $row = $res->getCurrentRow();
            $the_index = $row['id'];
            return $the_index;
 
        }else{
            //print a warning if there is more than one such type.  Should never happen.
            print "\n<b>Warning!<\b> The Type with domain ".$type->getDomain().", authority ".$type->getAuthority().", and keyword ".$type->getKeyword()." is not unique--there are ".$res->getNumberOfRows()." copies.\n";
 
 
            //return either one anyway.
            $row = $res->getCurrentRow();
            $the_index = $row['id'];
            return $the_index;
 
        }
 
    }
 
    /**
     * Given the object in table $table with id $id, change the field with name $key to $value
     * 
     * @param object Id $id The Id of the object in question
     * @param string $table The table that our object resides in
     * @param string $key The name of the field
     * @param mixed $value The value to pass in
     * 
     * 
     * @access private
     */
    function _setField($id, $table, $key, $value)
    {
        //just an update query
        $dbHandler = Services::getService("DBHandler");
        $query= new UpdateQuery;
        $query->setTable($table);
        $query->addWhere("id='".addslashes($id->getIdString())."'");
        $query->setColumns(array(addslashes($key)));
        $query->setValues(array("'".addslashes($value)."'"));
        $dbHandler->query($query);
 
 
    }
 
    /**
     * Given the object in table $table with id $id, get the field with name $key
     * 
     * @param object Id $id The Id of the object in question
     * @param string $table The table that our object resides in
     * @param string $key The name of the field
     * 
     * @return string 
     * 
     * @access private
     */
    function _getField($id, $table, $key)
    {
        
        //just a select query
        $dbHandler = Services::getService("DBHandler");
        $query= new SelectQuery;
        $query->addTable($table);
        $query->addWhere("id='".addslashes($id->getIdString())."'");
        $query->addColumn(addslashes($key));
        $res=$dbHandler->query($query);
        $row = $res->getCurrentRow();
        $ret=$row[$key];
        return $ret;
    }
    
}
 
?>