Index: lams_central/src/java/org/lamsfoundation/lams/web/qb/EditQbQuestionController.java
===================================================================
diff -u -rda30e197f54c6bc1c0d6d9d5dbcdde3c4632d329 -r80ab947256f1314103a88c68432755741615271b
--- lams_central/src/java/org/lamsfoundation/lams/web/qb/EditQbQuestionController.java	(.../EditQbQuestionController.java)	(revision da30e197f54c6bc1c0d6d9d5dbcdde3c4632d329)
+++ lams_central/src/java/org/lamsfoundation/lams/web/qb/EditQbQuestionController.java	(.../EditQbQuestionController.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -5,11 +5,9 @@
 import java.util.Collection;
 import java.util.Date;
 import java.util.List;
-import java.util.Optional;
 import java.util.TreeSet;
 
 import javax.servlet.ServletException;
-import javax.servlet.ServletOutputStream;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -64,7 +62,7 @@
 
 	//TODO think about where do we need to get ContentFolderID, and whether it's a good idea to generate a new one each time
 	String contentFolderID = FileUtil.generateUniqueContentFolderID();
-	
+
 	QbQuestionForm questionForm = new QbQuestionForm();
 	//we need to set form as a request attribute, as long as we use jsps from another context from the Assessment tool
 	request.setAttribute("assessmentQuestionForm", questionForm);
@@ -99,12 +97,12 @@
 	Integer type = NumberUtils.toInt(request.getParameter(QbConstants.ATTR_QUESTION_TYPE));
 //	sessionMap.put(QbConstants.ATTR_QUESTION_TYPE, type);
 	request.setAttribute(AttributeNames.PARAM_CONTENT_FOLDER_ID, contentFolderID);
-	
-	String jspPageName = getAuthoringJspByQuestionType(type);
+
+	String jspPageName = EditQbQuestionController.getAuthoringJspByQuestionType(type);
 	forwardToAssessmentJsp(jspPageName, request, response);
 	return null;
     }
-    
+
     /**
      * Display edit page for existed assessment question.
      */
@@ -121,17 +119,17 @@
 	//we need to set form as a request attribute, as long as we use jsps from another context from the Assessment tool
 	request.setAttribute("assessmentQuestionForm", questionForm);
 	QbUtils.fillFormWithQbQuestion(qbQuestion, questionForm, request);
-	
+
 	//store uid as displayOrder in order to use it later during question saving
 	questionForm.setDisplayOrder(qbQuestionUid.intValue());
-	
+
 	//TODO think about where do we need to get ContentFolderID, and whether it's a good idea to generate a new one each time
 	String contentFolderID = FileUtil.generateUniqueContentFolderID();
 	questionForm.setContentFolderID(contentFolderID);
 	request.setAttribute(AttributeNames.PARAM_CONTENT_FOLDER_ID, contentFolderID);
-	
-	String jspPageName = getAuthoringJspByQuestionType(qbQuestion.getType());
-	forwardToAssessmentJsp(jspPageName, request, response);	
+
+	String jspPageName = EditQbQuestionController.getAuthoringJspByQuestionType(qbQuestion.getType());
+	forwardToAssessmentJsp(jspPageName, request, response);
 	return null;
     }
 
@@ -140,7 +138,8 @@
      * <code>HttpSession</code> AssessmentQuestionList. Notice, this save is not persist them into database, just save
      * <code>HttpSession</code> temporarily. Only they will be persist when the entire authoring page is being
      * persisted.
-     * @throws IOException 
+     * 
+     * @throws IOException
      */
     @RequestMapping("/saveOrUpdateQuestion")
     @ResponseBody
@@ -149,18 +148,18 @@
 	//find according question
 	QbQuestion qbQuestion = null;
 	Long oldQuestionUid = null;
-	
+
 	// add
-	if (questionForm.getDisplayOrder() == -1) { 
+	if (questionForm.getDisplayOrder() == -1) {
 	    qbQuestion = new QbQuestion();
 	    qbQuestion.setType(questionForm.getQuestionType());
-	    
-	// edit
+
+	    // edit
 	} else {
 	    oldQuestionUid = Long.valueOf(questionForm.getDisplayOrder());
 	    qbQuestion = qbService.getQbQuestionByUid(oldQuestionUid);
 	}
-	
+
 	boolean IS_AUTHORING_RESTRICTED = false;
 	int isQbQuestionModified = QbUtils.extractFormToQbQuestion(qbQuestion, questionForm, request, qbService,
 		IS_AUTHORING_RESTRICTED);
@@ -178,48 +177,49 @@
 		qbQuestion = qbQuestion.clone();
 		qbQuestion.clearID();
 		qbQuestion.setVersion(1);
-		qbQuestion.setQuestionId(qbService.getMaxQuestionId()+1);
+		qbQuestion.setQuestionId(qbService.getMaxQuestionId() + 1);
 		qbQuestion.setCreateDate(new Date());
-		
+
 	    }
 		break;
 	}
 	boolean belongsToNoCollection = qbQuestion.getUid() == null;
 	userManagementService.save(qbQuestion);
-	
+
 	//in case of new question - add it to specified collection
 	if (belongsToNoCollection) {
 
 	    Long collectionUid = questionForm.getCollectionUid();
 	    //try to get collection from the old question
 	    if (collectionUid != null && collectionUid.equals(-1L)) {
-		Collection<QbCollection> existingCollections = qbService.getQuestionCollections(oldQuestionUid);
+		Collection<QbCollection> existingCollections = qbService.getQuestionCollectionsByUid(oldQuestionUid);
 		collectionUid = existingCollections.stream().findFirst().map(collection -> collection.getUid())
 			.orElse(null);
 	    }
 
 	    if (collectionUid != null && !collectionUid.equals(-1L)) {
-		qbService.addQuestionToCollection(collectionUid, qbQuestion.getUid(), false);
+		qbService.addQuestionToCollection(collectionUid, qbQuestion.getQuestionId(), false);
 	    }
 	}
-	
+
 	// add question case - return nothing
 	if (questionForm.getDisplayOrder() == -1) {
 	    return null;
-	    
-	// edit question case - return question's uid
+
+	    // edit question case - return question's uid
 	} else {
 	    response.setContentType("text/plain");
 	    response.setCharacterEncoding("UTF-8");
 	    return qbQuestion.getUid().toString();
 	}
     }
-    
+
     /**
      * Ajax call, will add one more input line for new resource item instruction.
      */
     @RequestMapping("/addOption")
-    public String addOption(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+    public String addOption(HttpServletRequest request, HttpServletResponse response)
+	    throws ServletException, IOException {
 	TreeSet<QbOption> optionList = QbUtils.getOptionsFromRequest(qbService, request, false);
 	QbOption option = new QbOption();
 	int maxSeq = 1;
@@ -243,7 +243,8 @@
      * Ajax call, will add one more input line for new Unit.
      */
     @RequestMapping("/newUnit")
-    public String newUnit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+    public String newUnit(HttpServletRequest request, HttpServletResponse response)
+	    throws ServletException, IOException {
 	TreeSet<QbQuestionUnit> unitList = QbUtils.getUnitsFromRequest(qbService, request, false);
 	QbQuestionUnit unit = new QbQuestionUnit();
 	int maxSeq = 1;
@@ -258,7 +259,7 @@
 	forwardToAssessmentJsp("unitlist.jsp", request, response);
 	return null;
     }
-    
+
     /**
      * Get back jsp name.
      */
@@ -297,14 +298,16 @@
     }
 
     /**
-     *  Forwards to the specified jsp page from Assessment tool.
+     * Forwards to the specified jsp page from Assessment tool.
      */
     private void forwardToAssessmentJsp(String jspPageName, HttpServletRequest request, HttpServletResponse response)
 	    throws ServletException, IOException {
 	String serverURLContextPath = Configuration.get(ConfigurationKeys.SERVER_URL_CONTEXT_PATH);
 	serverURLContextPath = serverURLContextPath.startsWith("/") ? serverURLContextPath : "/" + serverURLContextPath;
 	serverURLContextPath += serverURLContextPath.endsWith("/") ? "" : "/";
-	applicationcontext.getServletContext().getContext(serverURLContextPath + "tool/" + CommonConstants.TOOL_SIGNATURE_ASSESSMENT)
-		.getRequestDispatcher("/pages/authoring/parts/" + jspPageName +"?lessonID=1").forward(request, response);
+	applicationcontext.getServletContext()
+		.getContext(serverURLContextPath + "tool/" + CommonConstants.TOOL_SIGNATURE_ASSESSMENT)
+		.getRequestDispatcher("/pages/authoring/parts/" + jspPageName + "?lessonID=1")
+		.forward(request, response);
     }
 }
Index: lams_central/src/java/org/lamsfoundation/lams/web/qb/ImsQtiController.java
===================================================================
diff -u -r28f74fe44f679cfe7305cb1ddf42150f2de4c52c -r80ab947256f1314103a88c68432755741615271b
--- lams_central/src/java/org/lamsfoundation/lams/web/qb/ImsQtiController.java	(.../ImsQtiController.java)	(revision 28f74fe44f679cfe7305cb1ddf42150f2de4c52c)
+++ lams_central/src/java/org/lamsfoundation/lams/web/qb/ImsQtiController.java	(.../ImsQtiController.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -31,7 +31,7 @@
 
 /**
  * Exports and imports IMS QTI questions.
- * 
+ *
  * @author Andrey Balan
  */
 @Controller
@@ -45,10 +45,10 @@
 
     @Autowired
     private IQbService qbService;
-    
+
     @Autowired
     private IUserManagementService userManagementService;
-    
+
     /**
      * Parses questions extracted from IMS QTI file and adds them as new QB questions.
      */
@@ -57,15 +57,15 @@
     public void saveQTI(HttpServletRequest request, @RequestParam long collectionUid,
 	    @RequestParam String contentFolderID) throws UnsupportedEncodingException {
 	int questionId = qbService.getMaxQuestionId();
-	
+
 	Question[] questions = QuestionParser.parseQuestionChoiceForm(request);
 	for (Question question : questions) {
 	    QbQuestion qbQuestion = new QbQuestion();
 	    qbQuestion.setName(question.getTitle());
 	    qbQuestion.setDescription(QuestionParser.processHTMLField(question.getText(), false, contentFolderID,
 		    question.getResourcesFolderPath()));
-	    qbQuestion.setFeedback(QuestionParser.processHTMLField(question.getFeedback(), false,
-		    contentFolderID, question.getResourcesFolderPath()));
+	    qbQuestion.setFeedback(QuestionParser.processHTMLField(question.getFeedback(), false, contentFolderID,
+		    question.getResourcesFolderPath()));
 	    qbQuestion.setPenaltyFactor(0);
 	    qbQuestion.setQuestionId(++questionId);
 
@@ -298,15 +298,15 @@
 
 	    qbQuestion.setMaxMark(questionMark);
 	    userManagementService.save(qbQuestion);
-	    
-	    qbService.addQuestionToCollection(collectionUid, qbQuestion.getUid(), false);
-	    
+
+	    qbService.addQuestionToCollection(collectionUid, qbQuestion.getQuestionId(), false);
+
 	    if (log.isDebugEnabled()) {
 		log.debug("Imported QTI question. Name: " + qbQuestion.getName() + ", uid: " + qbQuestion.getUid());
 	    }
 	}
     }
-    
+
     /**
      * Exports QB question as IMS QTI package.
      */
@@ -390,8 +390,7 @@
 
 			    answer.setText(assessmentAnswer.getName());
 			    answer.setScore(
-				    isCorrectAnswer ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue()
-					    : 0);
+				    isCorrectAnswer ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
 			    answer.setFeedback(isCorrectAnswer ? qbQuestion.getFeedbackOnCorrect()
 				    : qbQuestion.getFeedbackOnIncorrect());
 
@@ -422,18 +421,16 @@
 		    // true/false question is basically the same for QTI, just with special answers
 		    Answer trueAnswer = new Answer();
 		    trueAnswer.setText("True");
-		    trueAnswer.setScore(
-			    isTrueCorrect ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
-		    trueAnswer.setFeedback(isTrueCorrect ? qbQuestion.getFeedbackOnCorrect()
-			    : qbQuestion.getFeedbackOnIncorrect());
+		    trueAnswer.setScore(isTrueCorrect ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
+		    trueAnswer.setFeedback(
+			    isTrueCorrect ? qbQuestion.getFeedbackOnCorrect() : qbQuestion.getFeedbackOnIncorrect());
 		    answers.add(trueAnswer);
 
 		    Answer falseAnswer = new Answer();
 		    falseAnswer.setText("False");
-		    falseAnswer.setScore(
-			    !isTrueCorrect ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
-		    falseAnswer.setFeedback(!isTrueCorrect ? qbQuestion.getFeedbackOnCorrect()
-			    : qbQuestion.getFeedbackOnIncorrect());
+		    falseAnswer.setScore(!isTrueCorrect ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
+		    falseAnswer.setFeedback(
+			    !isTrueCorrect ? qbQuestion.getFeedbackOnCorrect() : qbQuestion.getFeedbackOnIncorrect());
 		    answers.add(falseAnswer);
 		    break;
 
@@ -476,8 +473,7 @@
 			boolean isCorrectAnswer = assessmentAnswer.isCorrect();
 
 			answer.setText(assessmentAnswer.getName());
-			answer.setScore(
-				isCorrectAnswer ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
+			answer.setScore(isCorrectAnswer ? Integer.valueOf(qbQuestion.getMaxMark()).floatValue() : 0);
 			answer.setFeedback(isCorrectAnswer ? qbQuestion.getFeedbackOnCorrect()
 				: qbQuestion.getFeedbackOnIncorrect());
 
Index: lams_central/src/java/org/lamsfoundation/lams/web/qb/QbCollectionController.java
===================================================================
diff -u -r26ce32081def8b8d0a0e38f513100920d33dbef1 -r80ab947256f1314103a88c68432755741615271b
--- lams_central/src/java/org/lamsfoundation/lams/web/qb/QbCollectionController.java	(.../QbCollectionController.java)	(revision 26ce32081def8b8d0a0e38f513100920d33dbef1)
+++ lams_central/src/java/org/lamsfoundation/lams/web/qb/QbCollectionController.java	(.../QbCollectionController.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -139,9 +139,11 @@
 		rowElement.setAttribute(CommonConstants.ELEMENT_ID, uid);
 
 		// the last cell is for creating stats button
-		String usage = showUsage ? String.valueOf(qbService.getCountQuestionActivities(question.getUid()))
+		String usage = showUsage
+			? String.valueOf(qbService.getCountQuestionActivitiesByQuestionId(question.getQuestionId()))
 			: null;
-		String[] data = { uid, WebUtil.removeHTMLtags(question.getName()).trim(), question.getType().toString(),
+		String[] data = { question.getQuestionId().toString(),
+			WebUtil.removeHTMLtags(question.getName()).trim(), question.getType().toString(),
 			question.getVersion().toString(), usage, uid };
 
 		for (String cell : data) {
@@ -168,18 +170,18 @@
 
     @RequestMapping("/removeCollectionQuestion")
     @ResponseBody
-    public void removeCollectionQuestion(@RequestParam long collectionUid, @RequestParam long qbQuestionUid) {
-	qbService.removeQuestionFromCollection(collectionUid, qbQuestionUid);
+    public void removeCollectionQuestion(@RequestParam long collectionUid, @RequestParam int qbQuestionId) {
+	qbService.removeQuestionFromCollectionByQuestionId(collectionUid, qbQuestionId);
     }
 
     @RequestMapping("/addCollectionQuestion")
     @ResponseBody
     public void addCollectionQuestion(@RequestParam long targetCollectionUid, @RequestParam boolean copy,
-	    @RequestParam long qbQuestionUid) {
+	    @RequestParam int qbQuestionId) {
 	if (!Configuration.getAsBoolean(ConfigurationKeys.QB_COLLECTIONS_TRANSFER_ALLOW)) {
 	    throw new SecurityException("Transfering questions between collections is disabled");
 	}
-	qbService.addQuestionToCollection(targetCollectionUid, qbQuestionUid, copy);
+	qbService.addQuestionToCollection(targetCollectionUid, qbQuestionId, copy);
     }
 
     @RequestMapping("/addCollection")
Index: lams_central/src/java/org/lamsfoundation/lams/web/qb/QbStatsController.java
===================================================================
diff -u -rca75b4c508f9d195245818cdd4574f335e75d9c6 -r80ab947256f1314103a88c68432755741615271b
--- lams_central/src/java/org/lamsfoundation/lams/web/qb/QbStatsController.java	(.../QbStatsController.java)	(revision ca75b4c508f9d195245818cdd4574f335e75d9c6)
+++ lams_central/src/java/org/lamsfoundation/lams/web/qb/QbStatsController.java	(.../QbStatsController.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -60,7 +60,7 @@
 	QbStatsDTO stats = qbService.getQbQuestionStats(qbQuestionUid);
 	model.addAttribute("stats", stats);
 
-	Collection<QbCollection> existingCollections = qbService.getQuestionCollections(qbQuestionUid);
+	Collection<QbCollection> existingCollections = qbService.getQuestionCollectionsByUid(qbQuestionUid);
 	model.addAttribute("existingCollections", existingCollections);
 
 	Integer userId = getUserId();
@@ -71,7 +71,7 @@
 	boolean permanentRemove = existingCollections.size() <= 1;
 	model.addAttribute("permanentRemove", permanentRemove);
 	model.addAttribute("permanentRemovePossible",
-		permanentRemove ? qbService.removeQuestionPossible(qbQuestionUid) : false);
+		permanentRemove ? qbService.removeQuestionPossibleByUid(qbQuestionUid) : false);
 
 	model.addAttribute("transferAllowed",
 		Configuration.getAsBoolean(ConfigurationKeys.QB_COLLECTIONS_TRANSFER_ALLOW));
Index: lams_central/src/java/org/lamsfoundation/lams/web/qb/XmlQuestionsController.java
===================================================================
diff -u -r1b530a88ae6d3a1e553081b3d56117ec5ad3622a -r80ab947256f1314103a88c68432755741615271b
--- lams_central/src/java/org/lamsfoundation/lams/web/qb/XmlQuestionsController.java	(.../XmlQuestionsController.java)	(revision 1b530a88ae6d3a1e553081b3d56117ec5ad3622a)
+++ lams_central/src/java/org/lamsfoundation/lams/web/qb/XmlQuestionsController.java	(.../XmlQuestionsController.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -4,37 +4,22 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.io.PrintWriter;
-import java.io.UnsupportedEncodingException;
 import java.util.ArrayList;
 import java.util.Date;
-import java.util.LinkedList;
 import java.util.List;
-import java.util.SortedSet;
-import java.util.TreeMap;
-import java.util.TreeSet;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
-import org.apache.commons.lang.StringUtils;
 import org.apache.log4j.Logger;
 import org.lamsfoundation.lams.learningdesign.service.ExportToolContentException;
 import org.lamsfoundation.lams.qb.model.QbCollection;
-import org.lamsfoundation.lams.qb.model.QbOption;
 import org.lamsfoundation.lams.qb.model.QbQuestion;
 import org.lamsfoundation.lams.qb.service.IQbService;
-import org.lamsfoundation.lams.questions.Answer;
-import org.lamsfoundation.lams.questions.Question;
-import org.lamsfoundation.lams.questions.QuestionExporter;
-import org.lamsfoundation.lams.questions.QuestionParser;
 import org.lamsfoundation.lams.usermanagement.service.IUserManagementService;
 import org.lamsfoundation.lams.util.FileUtil;
-import org.lamsfoundation.lams.util.MessageService;
-import org.lamsfoundation.lams.util.WebUtil;
-import org.lamsfoundation.lams.web.util.SessionMap;
 import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestParam;
@@ -47,7 +32,7 @@
 
 /**
  * Exports and imports questions from the given collection in XML format.
- * 
+ *
  * @author Andrey Balan
  */
 @Controller
@@ -57,7 +42,7 @@
 
     @Autowired
     private IQbService qbService;
-    
+
     @Autowired
     private IUserManagementService userManagementService;
 
@@ -78,7 +63,7 @@
     public void importQuestionsXml(@RequestParam("UPLOAD_FILE") MultipartFile file, HttpServletRequest request,
 	    @RequestParam long collectionUid) throws ServletException {
 	int questionId = qbService.getMaxQuestionId();
-	
+
 	List<String> toolsErrorMsgs = new ArrayList<>();
 	try {
 	    String uploadPath = FileUtil.createTempDirectory("_uploaded_2questions_xml");
@@ -96,15 +81,15 @@
 
 	    // import learning design
 	    String fullFilePath = destinationFile.getAbsolutePath();// FileUtil.getFullPath(learningDesignPath,
-							       // ExportToolContentService.LEARNING_DESIGN_FILE_NAME);
+	    // ExportToolContentService.LEARNING_DESIGN_FILE_NAME);
 	    List<QbQuestion> questions = (List<QbQuestion>) FileUtil.getObjectFromXML(null, fullFilePath);
 	    if (questions != null) {
 		for (QbQuestion qbQuestion : questions) {
 		    qbQuestion.setQuestionId(++questionId);
 		    qbQuestion.setCreateDate(new Date());
 		    userManagementService.save(qbQuestion);
 
-		    qbService.addQuestionToCollection(collectionUid, qbQuestion.getUid(), false);
+		    qbService.addQuestionToCollection(collectionUid, qbQuestion.getQuestionId(), false);
 
 		    if (log.isDebugEnabled()) {
 			log.debug("Imported XML question. Name: " + qbQuestion.getName() + ", uid: "
@@ -127,13 +112,14 @@
      * Exports xml format questions from question collection.
      */
     @RequestMapping("/exportQuestionsXml")
-    public void exportQuestionsXml(HttpServletRequest request, HttpServletResponse response, @RequestParam long collectionUid) {
+    public void exportQuestionsXml(HttpServletRequest request, HttpServletResponse response,
+	    @RequestParam long collectionUid) {
 	List<QbQuestion> qbQuestions = qbService.getCollectionQuestions(collectionUid);
 	String errors = null;
 	try {
 	    ArrayList<QbQuestion> questionsToExport = new ArrayList<>();
 	    for (QbQuestion qbQuestion : qbQuestions) {
-		QbQuestion clonedQuestion = (QbQuestion) qbQuestion.clone();
+		QbQuestion clonedQuestion = qbQuestion.clone();
 		clonedQuestion.clearID();
 		clonedQuestion.setVersion(1);
 		questionsToExport.add(clonedQuestion);
Index: lams_central/web/qb/collection.jsp
===================================================================
diff -u -r26ce32081def8b8d0a0e38f513100920d33dbef1 -r80ab947256f1314103a88c68432755741615271b
--- lams_central/web/qb/collection.jsp	(.../collection.jsp)	(revision 26ce32081def8b8d0a0e38f513100920d33dbef1)
+++ lams_central/web/qb/collection.jsp	(.../collection.jsp)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -111,7 +111,7 @@
 			    	"Actions"
 			    ],
 			    colModel:[
-			    	{name:'id', index:'uid', sortable:true, hidden:true, width: 10},
+			    	{name:'id', index:'uid', sortable:true, hidden:false, width: 10},
 			    	{name:'name', index:'name', sortable:true, search:true, autoencode:true, formatter: questionNameFormatter},
 			    	{name:'questionType', index:'questionType', width:0, hidden: true},
 			    	{name:'questionVersion', index:'questionVersion', width:0, hidden: true},
Index: lams_central/web/qb/stats.jsp
===================================================================
diff -u -r57a3647e9f7b79d5fe02d9727194311b4930d867 -r80ab947256f1314103a88c68432755741615271b
--- lams_central/web/qb/stats.jsp	(.../stats.jsp)	(revision 57a3647e9f7b79d5fe02d9727194311b4930d867)
+++ lams_central/web/qb/stats.jsp	(.../stats.jsp)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -59,10 +59,13 @@
 	<script type="text/javascript" src="<lams:LAMSURL/>includes/javascript/thickbox.js"></script>
 	<script type="text/javascript">
 		var permanentRemove = ${permanentRemove},
-			permanentRemovePossible = ${permanentRemovePossible};
+			permanentRemovePossible = ${permanentRemovePossible},
+			optionsExist = ${not empty question.qbOptions};
 		
 		$(document).ready(function(){
-			drawChart('bar', 'chartDiv', ${stats.answersJSON});
+			if (optionsExist) {
+				drawChart('bar', 'chartDiv', ${stats.answersJSON});
+			}
 			$("time.timeago").timeago();
 		});
 		
@@ -76,7 +79,7 @@
 				'data' : {
 					'targetCollectionUid' : targetCollectionUid,
 					'copy'				  : copy,
-					'qbQuestionUid'	      : ${question.uid}
+					'qbQuestionId'	      : ${question.questionId}
 				},
 				'cache' : false
 			}).done(function(){
@@ -101,7 +104,7 @@
 				'dataType' : 'text',
 				'data' : {
 					'collectionUid' : collectionUid,
-					'qbQuestionUid'	: ${question.uid}
+					'qbQuestionId'	: ${question.questionId}
 				},
 				'cache' : false
 			}).done(function(){
Index: lams_common/src/java/org/lamsfoundation/lams/dbupdates/patch20190531.sql
===================================================================
diff -u -rca75b4c508f9d195245818cdd4574f335e75d9c6 -r80ab947256f1314103a88c68432755741615271b
--- lams_common/src/java/org/lamsfoundation/lams/dbupdates/patch20190531.sql	(.../patch20190531.sql)	(revision ca75b4c508f9d195245818cdd4574f335e75d9c6)
+++ lams_common/src/java/org/lamsfoundation/lams/dbupdates/patch20190531.sql	(.../patch20190531.sql)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -14,10 +14,10 @@
 							    );
 							    
 CREATE TABLE lams_qb_collection_question (`collection_uid`  BIGINT NOT NULL,
-									      `qb_question_uid` BIGINT NOT NULL,
+									      `qb_question_id` INT NOT NULL,
 									   	  CONSTRAINT FK_lams_qb_collection_question_1 FOREIGN KEY (collection_uid) REFERENCES lams_qb_collection (uid)
 											ON DELETE CASCADE ON UPDATE CASCADE,
-									   	  CONSTRAINT FK_lams_qb_collection_question_2 FOREIGN KEY (qb_question_uid) REFERENCES lams_qb_question (uid)
+									   	  CONSTRAINT FK_lams_qb_collection_question_2 FOREIGN KEY (qb_question_id) REFERENCES lams_qb_question (question_id)
 											ON DELETE CASCADE ON UPDATE CASCADE
 									  );
 							   				    
@@ -33,7 +33,7 @@
 INSERT INTO lams_qb_collection VALUES (1, 'Public questions', NULL, false);
 
 INSERT INTO lams_qb_collection_question
-	SELECT 1, uid FROM lams_qb_question;
+	SELECT 1, question_id FROM lams_qb_question;
 	
 INSERT INTO lams_configuration VALUES
 ('QbCollectionsTransferEnable', 'true', 'config.qb.collections.transfer.enable', 'config.header.qb', 'BOOLEAN', 1);
Index: lams_common/src/java/org/lamsfoundation/lams/qb/dao/IQbDAO.java
===================================================================
diff -u -rba4cb0681d080596444ca44c644a8ea0fdd8e743 -r80ab947256f1314103a88c68432755741615271b
--- lams_common/src/java/org/lamsfoundation/lams/qb/dao/IQbDAO.java	(.../IQbDAO.java)	(revision ba4cb0681d080596444ca44c644a8ea0fdd8e743)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/dao/IQbDAO.java	(.../IQbDAO.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -32,8 +32,10 @@
 
     List<ToolActivity> getQuestionActivities(long qbQuestionUid);
 
-    int getCountQuestionActivities(long qbQuestionUid);
+    int getCountQuestionActivitiesByUid(long qbQuestionUid);
 
+    int getCountQuestionActivitiesByQuestionId(int qbQuestionId);
+
     List<QbQuestion> getQuestionVersions(long qbQuestionUid);
 
     Map<Long, Long> getAnswerStatsForQbQuestion(long qbQuestionUid);
@@ -52,14 +54,16 @@
     List<QbQuestion> getCollectionQuestions(long collectionUid, Integer offset, Integer limit, String orderBy,
 	    String orderDirection, String search);
 
-    List<QbCollection> getQuestionCollections(long qbQuestionUid);
+    List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid);
 
+    List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId);
+
     int getCountCollectionQuestions(long collectionUid, String search);
 
-    void addCollectionQuestion(long collectionUid, long qbQuestionUid);
+    void addCollectionQuestion(long collectionUid, int qbQuestionId);
 
-    void removeCollectionQuestion(long collectionUid, long qbQuestionUid);
+    void removeCollectionQuestion(long collectionUid, int qbQuestionId);
 
-    Set<Long> getCollectionQuestionUidsExcluded(long collectionUid, Collection<Long> qbQuestionUids);
+    Set<Integer> getCollectionQuestionIdsExcluded(long collectionUid, Collection<Integer> qbQuestionIds);
 
 }
\ No newline at end of file
Index: lams_common/src/java/org/lamsfoundation/lams/qb/dao/hibernate/QbDAO.java
===================================================================
diff -u -re6b461918b2b8c7e791407b868c5f5b1991c7744 -r80ab947256f1314103a88c68432755741615271b
--- lams_common/src/java/org/lamsfoundation/lams/qb/dao/hibernate/QbDAO.java	(.../QbDAO.java)	(revision e6b461918b2b8c7e791407b868c5f5b1991c7744)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/dao/hibernate/QbDAO.java	(.../QbDAO.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -23,18 +23,23 @@
 public class QbDAO extends LAMSBaseDAO implements IQbDAO {
 
     private static final String FIND_MAX_QUESTION_ID = "SELECT MAX(questionId) FROM QbQuestion";
+
     private static final String FIND_MAX_VERSION = "SELECT MAX(version) FROM QbQuestion AS q WHERE q.questionId = :questionId";
+
     private static final String FIND_QUESTION_ACTIVITIES = "SELECT a FROM ToolActivity AS a, QbToolQuestion AS q "
 	    + "WHERE a.toolContentId = q.toolContentId AND a.learningDesign.lessons IS NOT EMPTY AND q.qbQuestion.uid = :qbQuestionUid";
+
     private static final String FIND_QUESTION_VERSIONS = "SELECT q FROM QbQuestion AS q, QbQuestion AS r "
 	    + "WHERE q.questionId = r.questionId AND q.uid <> r.uid AND r.uid = :qbQuestionUid";
+
     private static final String FIND_ANSWER_STATS_BY_QB_QUESTION = "SELECT COALESCE(a.qb_option_uid, aa.question_option_uid) AS opt, COUNT(a.answer_uid) "
 	    + "FROM lams_qb_tool_question AS tq JOIN lams_qb_tool_answer AS a USING (tool_question_uid) "
 	    + "LEFT JOIN tl_lascrt11_answer_log AS sa ON a.answer_uid = sa.uid "
 	    + "LEFT JOIN tl_lascrt11_session AS ss ON sa.session_id = ss.session_id "
 	    + "LEFT JOIN tl_lascrt11_user AS su ON ss.uid = su.session_uid "
 	    + "LEFT JOIN tl_laasse10_option_answer AS aa ON a.answer_uid = aa.question_result_uid AND aa.answer_boolean = 1 "
 	    + "WHERE tq.qb_question_uid = :qbQuestionUid GROUP BY opt HAVING opt IS NOT NULL";
+
     private static final String FIND_ANSWERS_BY_ACTIVITY = "SELECT COALESCE(mcu.que_usr_id, su.user_id, au.user_id), "
 	    + "COALESCE(a.qb_option_uid, aa.question_option_uid) AS opt "
 	    + "FROM lams_learning_activity AS act JOIN lams_qb_tool_question AS tq USING (tool_content_id) "
@@ -49,26 +54,31 @@
 	    + "LEFT JOIN tl_laasse10_assessment_result AS ar ON aq.result_uid = ar.uid "
 	    + "LEFT JOIN tl_laasse10_user AS au ON ar.user_uid = au.uid "
 	    + "WHERE act.activity_id = :activityId AND tq.qb_question_uid = :qbQuestionUid HAVING opt IS NOT NULL";
+
     private static final String FIND_BURNING_QUESTIONS = "SELECT b.question, COUNT(bl.uid) FROM ScratchieBurningQuestion b LEFT OUTER JOIN "
 	    + "BurningQuestionLike AS bl ON bl.burningQuestion = b WHERE b.scratchieItem.qbQuestion.uid = :qbQuestionUid "
 	    + "GROUP BY b.question ORDER BY COUNT(bl.uid) DESC";
 
     private static final String FIND_COLLECTION_QUESTIONS = "SELECT q.* FROM lams_qb_collection_question AS cq "
-	    + "JOIN lams_qb_question AS q ON cq.qb_question_uid = q.uid WHERE cq.collection_uid = :collectionUid";
+	    + "JOIN lams_qb_question AS q ON cq.qb_question_id = q.question_id WHERE cq.collection_uid = :collectionUid";
 
-    private static final String FIND_QUESTION_COLLECTIONS = "SELECT c.* FROM lams_qb_collection_question AS cq "
-	    + "JOIN lams_qb_collection AS c ON cq.collection_uid = c.uid WHERE cq.qb_question_uid = :qbQuestionUid";
+    private static final String FIND_QUESTION_COLLECTIONS_BY_UID = "SELECT c.* FROM lams_qb_collection_question AS cq "
+	    + "JOIN lams_qb_collection AS c ON cq.collection_uid = c.uid JOIN lams_qb_question AS q ON cq.qb_question_id = q.question_id "
+	    + "WHERE q.uid = :qbQuestionUid";
 
-    private static final String ADD_COLLECTION_QUESTION = "INSERT INTO lams_qb_collection_question VALUES (:collectionUid, :qbQuestionUid)";
+    private static final String FIND_QUESTION_COLLECTIONS_BY_QUESTION_ID = "SELECT c.* FROM lams_qb_collection_question AS cq "
+	    + "JOIN lams_qb_collection AS c ON cq.collection_uid = c.uid WHERE cq.qb_question_id = :qbQuestionId";
 
+    private static final String ADD_COLLECTION_QUESTION = "INSERT INTO lams_qb_collection_question VALUES (:collectionUid, :qbQuestionId)";
+
     private static final String EXISTS_COLLECTION_QUESTION = "SELECT 1 FROM lams_qb_collection_question WHERE collection_uid = :collectionUid "
-	    + "AND qb_question_uid = :qbQuestionUid";
+	    + "AND qb_question_id = :qbQuestionId";
 
     private static final String REMOVE_COLLECTION_QUESTION = "DELETE FROM lams_qb_collection_question WHERE collection_uid = :collectionUid "
-	    + "AND qb_question_uid = :qbQuestionUid";
+	    + "AND qb_question_id = :qbQuestionId";
 
-    private static final String FIND_COLLECTION_QUESTIONS_EXCLUDED = "SELECT qb_question_uid FROM lams_qb_collection_question "
-	    + "WHERE collection_uid = :collectionUid AND qb_question_uid NOT IN :qbQuestionUids";
+    private static final String FIND_COLLECTION_QUESTIONS_EXCLUDED = "SELECT qb_question_id FROM lams_qb_collection_question "
+	    + "WHERE collection_uid = :collectionUid AND qb_question_id NOT IN :qbQuestionIds";
 
     @Override
     public QbQuestion getQbQuestionByUid(Long qbQuestionUid) {
@@ -79,7 +89,7 @@
     @Override
     public List<QbQuestion> getQbQuestionsByQuestionId(Integer questionId) {
 	final String FIND_QUESTIONS_BY_QUESTION_ID = "FROM " + QbQuestion.class.getName()
-		+ " WHERE questionId = :questionId ORDER BY version ASC";
+		+ " WHERE questionId = :questionId ORDER BY version DESC";
 
 	Query q = getSession().createQuery(FIND_QUESTIONS_BY_QUESTION_ID, QbQuestion.class);
 	q.setParameter("questionId", questionId);
@@ -109,12 +119,20 @@
     }
 
     @Override
-    public int getCountQuestionActivities(long qbQuestionUid) {
+    public int getCountQuestionActivitiesByUid(long qbQuestionUid) {
 	return ((Long) getSession().createQuery(FIND_QUESTION_ACTIVITIES.replace("SELECT a", "SELECT COUNT(a)"))
 		.setParameter("qbQuestionUid", qbQuestionUid).getSingleResult()).intValue();
     }
 
     @Override
+    public int getCountQuestionActivitiesByQuestionId(int qbQuestionId) {
+	return ((Long) getSession()
+		.createQuery(FIND_QUESTION_ACTIVITIES.replace("SELECT a", "SELECT COUNT(a)")
+			.replace("uid = :qbQuestionUid", "questionId = :qbQuestionId"))
+		.setParameter("qbQuestionId", qbQuestionId).getSingleResult()).intValue();
+    }
+
+    @Override
     @SuppressWarnings("unchecked")
     public List<QbQuestion> getQuestionVersions(long qbQuestionUid) {
 	return this.getSession().createQuery(FIND_QUESTION_VERSIONS).setParameter("qbQuestionUid", qbQuestionUid)
@@ -193,9 +211,9 @@
 
     @Override
     public int getCountQbQuestions(Integer questionType, String searchString) {
-	final String SELECT_QUESTIONS = "SELECT COUNT(DISTINCT question.uid) count " + " FROM lams_qb_question question  "
-		+ " LEFT OUTER JOIN lams_qb_option qboption " + "	ON qboption.qb_question_uid = question.uid "
-		+ " LEFT JOIN ("//help finding questions with the max available version
+	final String SELECT_QUESTIONS = "SELECT COUNT(DISTINCT question.uid) count "
+		+ " FROM lams_qb_question question  " + " LEFT OUTER JOIN lams_qb_option qboption "
+		+ "	ON qboption.qb_question_uid = question.uid " + " LEFT JOIN ("//help finding questions with the max available version
 		+ "	SELECT biggerQuestion.* FROM lams_qb_question biggerQuestion "
 		+ " 		LEFT OUTER JOIN lams_qb_option qboption1 "
 		+ "		ON qboption1.qb_question_uid = biggerQuestion.uid "
@@ -209,7 +227,8 @@
 		+ " OR question.name LIKE CONCAT('%', :searchString, '%') "
 		+ " OR REGEXP_REPLACE(qboption.name, '<[^>]*>+', '') LIKE CONCAT('%', :searchString, '%')) ";
 
-	Query query = getSession().createNativeQuery(SELECT_QUESTIONS).addScalar("count", IntegerType.INSTANCE);;
+	Query query = getSession().createNativeQuery(SELECT_QUESTIONS).addScalar("count", IntegerType.INSTANCE);
+	;
 	query.setParameter("questionType", questionType);
 	// support for custom search from a toolbar
 	searchString = searchString == null ? "" : searchString;
@@ -249,13 +268,20 @@
 
     @SuppressWarnings("unchecked")
     @Override
-    public List<QbCollection> getQuestionCollections(long qbQuestionUid) {
-	return getSession().createNativeQuery(FIND_QUESTION_COLLECTIONS).setParameter("qbQuestionUid", qbQuestionUid)
-		.addEntity(QbCollection.class).list();
+    public List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid) {
+	return getSession().createNativeQuery(FIND_QUESTION_COLLECTIONS_BY_UID)
+		.setParameter("qbQuestionUid", qbQuestionUid).addEntity(QbCollection.class).list();
     }
 
     @SuppressWarnings("unchecked")
     @Override
+    public List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId) {
+	return getSession().createNativeQuery(FIND_QUESTION_COLLECTIONS_BY_QUESTION_ID)
+		.setParameter("qbQuestionId", qbQuestionId).addEntity(QbCollection.class).list();
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
     public List<QbQuestion> getCollectionQuestions(long collectionUid, Integer offset, Integer limit, String orderBy,
 	    String orderDirection, String search) {
 	Query query = prepareCollectionQuestionsQuery(collectionUid, orderBy, orderDirection, search, false);
@@ -275,35 +301,35 @@
     }
 
     @Override
-    public void addCollectionQuestion(long collectionUid, long qbQuestionUid) {
-	if (!questionInCollectionExists(collectionUid, qbQuestionUid)) {
+    public void addCollectionQuestion(long collectionUid, int qbQuestionId) {
+	if (!questionInCollectionExists(collectionUid, qbQuestionId)) {
 	    getSession().createNativeQuery(ADD_COLLECTION_QUESTION).setParameter("collectionUid", collectionUid)
-		    .setParameter("qbQuestionUid", qbQuestionUid).executeUpdate();
+		    .setParameter("qbQuestionId", qbQuestionId).executeUpdate();
 	}
     }
 
     @Override
-    public void removeCollectionQuestion(long collectionUid, long qbQuestionUid) {
+    public void removeCollectionQuestion(long collectionUid, int qbQuestionId) {
 	getSession().createNativeQuery(REMOVE_COLLECTION_QUESTION).setParameter("collectionUid", collectionUid)
-		.setParameter("qbQuestionUid", qbQuestionUid).executeUpdate();
+		.setParameter("qbQuestionId", qbQuestionId).executeUpdate();
     }
 
     @SuppressWarnings("unchecked")
     @Override
-    public Set<Long> getCollectionQuestionUidsExcluded(long collectionUid, Collection<Long> qbQuestionUids) {
+    public Set<Integer> getCollectionQuestionIdsExcluded(long collectionUid, Collection<Integer> qbQuestionIds) {
 	List<BigInteger> queryResult = getSession().createNativeQuery(FIND_COLLECTION_QUESTIONS_EXCLUDED)
-		.setParameter("collectionUid", collectionUid).setParameterList("qbQuestionUids", qbQuestionUids)
+		.setParameter("collectionUid", collectionUid).setParameterList("qbQuestionIds", qbQuestionIds)
 		.getResultList();
-	Set<Long> result = new HashSet<>();
-	for (BigInteger uid : queryResult) {
-	    result.add(uid.longValue());
+	Set<Integer> result = new HashSet<>();
+	for (BigInteger questionId : queryResult) {
+	    result.add(questionId.intValue());
 	}
 	return result;
     }
 
-    private boolean questionInCollectionExists(long collectionUid, long qbQuestionUid) {
+    private boolean questionInCollectionExists(long collectionUid, int qbQuestionId) {
 	return !getSession().createNativeQuery(EXISTS_COLLECTION_QUESTION).setParameter("collectionUid", collectionUid)
-		.setParameter("qbQuestionUid", qbQuestionUid).getResultList().isEmpty();
+		.setParameter("qbQuestionId", qbQuestionId).getResultList().isEmpty();
     }
 
     private Query prepareCollectionQuestionsQuery(long collectionUid, String orderBy, String orderDirection,
Index: lams_common/src/java/org/lamsfoundation/lams/qb/service/IQbService.java
===================================================================
diff -u -r95b32ee3c7e813d17c11fe5391bbd5c5a951a64d -r80ab947256f1314103a88c68432755741615271b
--- lams_common/src/java/org/lamsfoundation/lams/qb/service/IQbService.java	(.../IQbService.java)	(revision 95b32ee3c7e813d17c11fe5391bbd5c5a951a64d)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/service/IQbService.java	(.../IQbService.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -5,12 +5,11 @@
 
 import org.lamsfoundation.lams.qb.dto.QbStatsActivityDTO;
 import org.lamsfoundation.lams.qb.dto.QbStatsDTO;
-
 import org.lamsfoundation.lams.qb.model.QbCollection;
 import org.lamsfoundation.lams.qb.model.QbOption;
 import org.lamsfoundation.lams.qb.model.QbQuestion;
-import org.lamsfoundation.lams.usermanagement.Organisation;
 import org.lamsfoundation.lams.qb.model.QbQuestionUnit;
+import org.lamsfoundation.lams.usermanagement.Organisation;
 
 public interface IQbService {
 
@@ -36,13 +35,13 @@
      * @return questions sharing the same questionId
      */
     List<QbQuestion> getQbQuestionsByQuestionId(Integer questionId);
-    
+
     /**
      * @param optionUid
      * @return QbOption by its uid. Besides, it releases returned object and associated qbQuestion from the cache.
      */
     QbOption getQbOptionByUid(Long optionUid);
-    
+
     /**
      * @param unitUid
      * @return QbQuestionUnit by its uid. Besides, it releases returned object and associated qbQuestion from the cache.
@@ -67,7 +66,7 @@
 	    String searchString);
 
     int getCountQbQuestions(Integer questionType, String searchString);
-
+
     QbCollection getCollectionByUid(Long collectionUid);
 
     QbCollection getPublicCollection();
@@ -85,8 +84,10 @@
 
     int getCountCollectionQuestions(long collectionUid, String search);
 
-    List<QbCollection> getQuestionCollections(long qbQuestionUid);
+    List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid);
 
+    List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId);
+
     QbCollection addCollection(int userId, String name);
 
     void removeCollection(long collectionUid);
@@ -97,24 +98,32 @@
 
     void unshareCollection(long collectionUid, int organisationId);
 
-    void addQuestionToCollection(long collectionUid, long qbQuestionUid, boolean copy);
+    void addQuestionToCollection(long collectionUid, int qbQuestionUid, boolean copy);
 
     void addQuestionToCollection(long sourceCollectionUid, long targetCollectionUid,
-	    Collection<Long> excludedQbQuestionUids, boolean copy);
+	    Collection<Integer> excludedQbQuestionIds, boolean copy);
 
-    boolean removeQuestionFromCollection(long collectionUid, long qbQuestionUid);
+    boolean removeQuestionFromCollectionByUid(long collectionUid, long qbQuestionUid);
 
-    Collection<Long> removeQuestionFromCollection(long collectionUid, Collection<Long> excludedQbQuestionUids);
+    boolean removeQuestionFromCollectionByQuestionId(long collectionUid, int qbQuestionId);
 
-    boolean removeQuestion(long qbQuestionUid);
+    Collection<Integer> removeQuestionFromCollection(long collectionUid, Collection<Integer> excludedQbQuestionIds);
 
-    boolean removeQuestionPossible(long qbQuestionUid);
+    boolean removeQuestionByUid(long qbQuestionUid);
 
+    boolean removeQuestionByQuestionId(int qbQuestionId);
+
+    boolean removeQuestionPossibleByUid(long qbQuestionUid);
+
+    boolean removeQuestionPossibleByQuestionId(int qbQuestionId);
+
     QbCollection getCollection(long collectionUid);
 
-    int getCountQuestionActivities(long qbQuestionUid);
+    int getCountQuestionActivitiesByUid(long qbQuestionUid);
 
+    int getCountQuestionActivitiesByQuestionId(int qbQuestionId);
+
     void changeCollectionName(long collectionUid, String name);
-
+
     void releaseFromCache(Object object);
-}
+}
Index: lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java
===================================================================
diff -u -r58b28b26165b1b600be40720c6a26fcf2110a8f1 -r80ab947256f1314103a88c68432755741615271b
--- lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java	(.../QbService.java)	(revision 58b28b26165b1b600be40720c6a26fcf2110a8f1)
+++ lams_common/src/java/org/lamsfoundation/lams/qb/service/QbService.java	(.../QbService.java)	(revision 80ab947256f1314103a88c68432755741615271b)
@@ -53,9 +53,8 @@
 
     private IUserManagementService userManagementService;
 
-    public static final Comparator<QbCollection> COLLECTION_NAME_COMPARATOR = (c1,
-	    c2) -> c1 == null || c1.getName() == null ? (c2 == null || c2.getName() == null ? 0 : -1)
-		    : c1.getName().compareTo(c2.getName());
+    public static final Comparator<QbCollection> COLLECTION_NAME_COMPARATOR = Comparator
+	    .comparing(QbCollection::getName);
 
     @Override
     public QbQuestion getQbQuestionByUid(Long qbQuestionUid) {
@@ -320,11 +319,16 @@
     }
 
     @Override
-    public List<QbCollection> getQuestionCollections(long qbQuestionUid) {
-	return qbDAO.getQuestionCollections(qbQuestionUid);
+    public List<QbCollection> getQuestionCollectionsByUid(long qbQuestionUid) {
+	return qbDAO.getQuestionCollectionsByUid(qbQuestionUid);
     }
 
     @Override
+    public List<QbCollection> getQuestionCollectionsByQuestionId(int qbQuestionId) {
+	return qbDAO.getQuestionCollectionsByQuestionId(qbQuestionId);
+    }
+
+    @Override
     public QbCollection addCollection(int userId, String name) {
 	QbCollection collection = new QbCollection();
 	collection.setName(name);
@@ -346,8 +350,8 @@
     }
 
     @Override
-    public boolean removeQuestion(long qbQuestionUid) {
-	boolean removeQuestionPossible = removeQuestionPossible(qbQuestionUid);
+    public boolean removeQuestionByUid(long qbQuestionUid) {
+	boolean removeQuestionPossible = removeQuestionPossibleByUid(qbQuestionUid);
 	if (!removeQuestionPossible) {
 	    // if the question is used in a Learning Design, do not allow to remove it
 	    return false;
@@ -357,13 +361,33 @@
     }
 
     @Override
-    public boolean removeQuestionPossible(long qbQuestionUid) {
+    public boolean removeQuestionByQuestionId(int qbQuestionId) {
+	boolean removeQuestionPossible = removeQuestionPossibleByQuestionId(qbQuestionId);
+	if (!removeQuestionPossible) {
+	    // if the question is used in a Learning Design, do not allow to remove it
+	    return false;
+	}
 	Map<String, Object> properties = new HashMap<>();
+	properties.put("questionId", qbQuestionId);
+	qbDAO.deleteByProperties(QbQuestion.class, properties);
+	return true;
+    }
+
+    @Override
+    public boolean removeQuestionPossibleByUid(long qbQuestionUid) {
+	Map<String, Object> properties = new HashMap<>();
 	properties.put("qbQuestion.uid", qbQuestionUid);
 	return qbDAO.countByProperties(QbToolQuestion.class, properties) == 0;
     }
 
     @Override
+    public boolean removeQuestionPossibleByQuestionId(int qbQuestionId) {
+	Map<String, Object> properties = new HashMap<>();
+	properties.put("qbQuestion.questionId", qbQuestionId);
+	return qbDAO.countByProperties(QbToolQuestion.class, properties) == 0;
+    }
+
+    @Override
     public Organisation shareCollection(long collectionUid, int organisationId) {
 	QbCollection collection = qbDAO.find(QbCollection.class, collectionUid);
 	if (collection.getUserId() == null || collection.isPersonal()) {
@@ -392,54 +416,62 @@
     }
 
     @Override
-    public void addQuestionToCollection(long collectionUid, long qbQuestionUid, boolean copy) {
-	long addQbQuestionUid = qbQuestionUid;
+    public void addQuestionToCollection(long collectionUid, int qbQuestionId, boolean copy) {
+	int addQbQuestionId = qbQuestionId;
 	if (copy) {
-	    QbQuestion question = getQbQuestionByUid(qbQuestionUid);
+	    List<QbQuestion> questions = getQbQuestionsByQuestionId(qbQuestionId);
+	    QbQuestion question = questions.get(0);
 	    QbQuestion newQuestion = question.clone();
-	    newQuestion.setQuestionId(getMaxQuestionId());
+	    addQbQuestionId = getMaxQuestionId();
+	    newQuestion.setQuestionId(addQbQuestionId);
 	    newQuestion.setVersion(1);
 	    newQuestion.setCreateDate(new Date());
 	    newQuestion.clearID();
 	    qbDAO.insert(newQuestion);
-	    addQbQuestionUid = newQuestion.getUid();
 	}
-	qbDAO.addCollectionQuestion(collectionUid, addQbQuestionUid);
+	qbDAO.addCollectionQuestion(collectionUid, addQbQuestionId);
     }
 
     @Override
     public void addQuestionToCollection(long sourceCollectionUid, long targetCollectionUid,
-	    Collection<Long> excludedQbQuestionUids, boolean copy) {
-	Collection<Long> includedUids = qbDAO.getCollectionQuestionUidsExcluded(sourceCollectionUid,
-		excludedQbQuestionUids);
-	for (Long uid : includedUids) {
-	    addQuestionToCollection(targetCollectionUid, uid, copy);
+	    Collection<Integer> excludedQbQuestionIds, boolean copy) {
+	Collection<Integer> includedIds = qbDAO.getCollectionQuestionIdsExcluded(sourceCollectionUid,
+		excludedQbQuestionIds);
+	for (Integer questionId : includedIds) {
+	    addQuestionToCollection(targetCollectionUid, questionId, copy);
 	}
     }
 
     @Override
-    public boolean removeQuestionFromCollection(long collectionUid, long qbQuestionUid) {
-	Collection<QbCollection> collections = getQuestionCollections(qbQuestionUid);
+    public boolean removeQuestionFromCollectionByUid(long collectionUid, long qbQuestionUid) {
+	QbQuestion question = getQbQuestionByUid(qbQuestionUid);
+	return removeQuestionFromCollectionByQuestionId(collectionUid, question.getQuestionId());
+    }
+
+    @Override
+    public boolean removeQuestionFromCollectionByQuestionId(long collectionUid, int qbQuestionId) {
+	Collection<QbCollection> collections = getQuestionCollectionsByQuestionId(qbQuestionId);
 	int size = collections.size();
 	if (size <= 1) {
 	    // if the question is in its last collection, try to remove it permanently
-	    return removeQuestion(qbQuestionUid);
+	    return removeQuestionByQuestionId(qbQuestionId);
 	}
-	qbDAO.removeCollectionQuestion(collectionUid, qbQuestionUid);
+	qbDAO.removeCollectionQuestion(collectionUid, qbQuestionId);
 	return true;
     }
 
     @Override
-    public Collection<Long> removeQuestionFromCollection(long collectionUid, Collection<Long> excludedQbQuestionUids) {
-	Collection<Long> includedUids = qbDAO.getCollectionQuestionUidsExcluded(collectionUid, excludedQbQuestionUids);
-	Collection<Long> retainedQuestionUids = new HashSet<>();
-	for (Long uid : includedUids) {
-	    boolean deleted = removeQuestionFromCollection(collectionUid, uid);
+    public Collection<Integer> removeQuestionFromCollection(long collectionUid,
+	    Collection<Integer> excludedQbQuestionIds) {
+	Collection<Integer> includedIds = qbDAO.getCollectionQuestionIdsExcluded(collectionUid, excludedQbQuestionIds);
+	Collection<Integer> retainedQuestionIds = new HashSet<>();
+	for (Integer questionId : includedIds) {
+	    boolean deleted = removeQuestionFromCollectionByQuestionId(collectionUid, questionId);
 	    if (!deleted) {
-		retainedQuestionUids.add(uid);
+		retainedQuestionIds.add(questionId);
 	    }
 	}
-	return retainedQuestionUids;
+	return retainedQuestionIds;
     }
 
     @Override
@@ -494,9 +526,14 @@
     }
 
     @Override
-    public int getCountQuestionActivities(long qbQuestionUid) {
-	return qbDAO.getCountQuestionActivities(qbQuestionUid);
+    public int getCountQuestionActivitiesByUid(long qbQuestionUid) {
+	return qbDAO.getCountQuestionActivitiesByUid(qbQuestionUid);
     }
+    
+    @Override
+    public int getCountQuestionActivitiesByQuestionId(int qbQuestionId) {
+	return qbDAO.getCountQuestionActivitiesByQuestionId(qbQuestionId);
+    }
 
     @Override
     public void changeCollectionName(long collectionUid, String name) {