diff --git a/src/it/java/teammates/it/ui/webapi/DeleteFeedbackResponseCommentActionIT.java b/src/it/java/teammates/it/ui/webapi/DeleteFeedbackResponseCommentActionIT.java
index d5a23c96277e..639dd803fed3 100644
--- a/src/it/java/teammates/it/ui/webapi/DeleteFeedbackResponseCommentActionIT.java
+++ b/src/it/java/teammates/it/ui/webapi/DeleteFeedbackResponseCommentActionIT.java
@@ -64,7 +64,7 @@ protected void testAccessControl() throws Exception {
         };
         Instructor instructorWhoGiveComment = typicalBundle.instructors.get("instructor1OfCourse1");
 
-        assertEquals(instructorWhoGiveComment.getEmail(), frc.getGiver());
+        assertEquals(instructorWhoGiveComment.getEmail(), frc.getGiver().getEmail());
         loginAsInstructor(instructorWhoGiveComment.getGoogleId());
         verifyCanAccess(submissionParams);
 
diff --git a/src/main/java/teammates/storage/sqlapi/FeedbackResponsesDb.java b/src/main/java/teammates/storage/sqlapi/FeedbackResponsesDb.java
index be497ae28264..c80cea3e6fc1 100644
--- a/src/main/java/teammates/storage/sqlapi/FeedbackResponsesDb.java
+++ b/src/main/java/teammates/storage/sqlapi/FeedbackResponsesDb.java
@@ -16,6 +16,7 @@
 import teammates.storage.sqlentity.FeedbackResponse;
 import teammates.storage.sqlentity.FeedbackSession;
 import teammates.storage.sqlentity.Section;
+import teammates.storage.sqlentity.User;
 
 import jakarta.persistence.criteria.CriteriaBuilder;
 import jakarta.persistence.criteria.CriteriaDelete;
@@ -130,10 +131,11 @@ public List<FeedbackResponse> getFeedbackResponsesFromGiverForQuestion(
         CriteriaQuery<FeedbackResponse> cq = cb.createQuery(FeedbackResponse.class);
         Root<FeedbackResponse> root = cq.from(FeedbackResponse.class);
         Join<FeedbackResponse, FeedbackQuestion> frJoin = root.join("feedbackQuestion");
+        Join<FeedbackResponse, User> uJoin = root.join("giver");
         cq.select(root)
                 .where(cb.and(
                         cb.equal(frJoin.get("id"), feedbackQuestionId),
-                        cb.equal(root.get("giver"), giverEmail)));
+                        cb.equal(uJoin.get("email"), giverEmail)));
         return HibernateUtil.createQuery(cq).getResultList();
     }
 
@@ -183,6 +185,11 @@ public List<FeedbackResponse> getResponsesForQuestion(UUID questionId) {
 
     /**
      * Checks whether a user has responses in a session.
+     * 
+     * @param giver the email of the giver.
+     * @param feedbackSessionName the name of the feedback session.
+     * @param courseId the identifier of the course.
+     * @return a boolean if there are responses from the given giver in this feedback session.
      */
     public boolean hasResponsesFromGiverInSession(
             String giver, String feedbackSessionName, String courseId) {
@@ -192,10 +199,11 @@ public boolean hasResponsesFromGiverInSession(
         Join<FeedbackResponse, FeedbackQuestion> fqJoin = root.join("feedbackQuestion");
         Join<FeedbackQuestion, FeedbackSession> fsJoin = fqJoin.join("feedbackSession");
         Join<FeedbackSession, Course> courseJoin = fsJoin.join("course");
+        Join<FeedbackResponse, User> uJoin = root.join("giver");
 
         cq.select(root)
                 .where(cb.and(
-                        cb.equal(root.get("giver"), giver),
+                        cb.equal(uJoin.get("email"), giver),
                         cb.equal(fsJoin.get("name"), feedbackSessionName),
                         cb.equal(courseJoin.get("id"), courseId)));
 
diff --git a/src/main/java/teammates/storage/sqlentity/FeedbackResponse.java b/src/main/java/teammates/storage/sqlentity/FeedbackResponse.java
index 0fc187c29693..94cd6528d5ee 100644
--- a/src/main/java/teammates/storage/sqlentity/FeedbackResponse.java
+++ b/src/main/java/teammates/storage/sqlentity/FeedbackResponse.java
@@ -48,7 +48,7 @@ public abstract class FeedbackResponse extends BaseEntity {
     @OneToMany(mappedBy = "feedbackResponse", cascade = CascadeType.REMOVE)
     private List<FeedbackResponseComment> feedbackResponseComments = new ArrayList<>();
 
-    @ManyToOne
+    @ManyToOne(cascade = {CascadeType.MERGE, CascadeType.REMOVE})
     @OnDelete(action = OnDeleteAction.CASCADE)
     @JoinColumn(name = "giverId", nullable = false)
     private User giver;
@@ -57,7 +57,7 @@ public abstract class FeedbackResponse extends BaseEntity {
     @JoinColumn(name = "giverSectionId")
     private Section giverSection;
 
-    @ManyToOne
+    @ManyToOne(cascade = {CascadeType.MERGE, CascadeType.REMOVE})
     @OnDelete(action = OnDeleteAction.CASCADE)
     @JoinColumn(name = "recipientId", nullable = false)
     private User recipient;
diff --git a/src/main/java/teammates/ui/webapi/DeleteFeedbackResponseCommentAction.java b/src/main/java/teammates/ui/webapi/DeleteFeedbackResponseCommentAction.java
index 5ca18c8f2528..926eedbd8e8e 100644
--- a/src/main/java/teammates/ui/webapi/DeleteFeedbackResponseCommentAction.java
+++ b/src/main/java/teammates/ui/webapi/DeleteFeedbackResponseCommentAction.java
@@ -133,7 +133,7 @@ void checkSpecificAccessControl() throws UnauthorizedAccessException {
             if (instructor == null) {
                 throw new UnauthorizedAccessException("Trying to access system using a non-existent instructor entity");
             }
-            if (comment.getGiver().equals(instructor.getEmail())) { // giver, allowed by default
+            if (comment.getGiver().getEmail().equals(instructor.getEmail())) { // giver, allowed by default
                 return;
             }
 
diff --git a/src/main/java/teammates/ui/webapi/GateKeeper.java b/src/main/java/teammates/ui/webapi/GateKeeper.java
index 75b73feefe07..33af78ad2ab1 100644
--- a/src/main/java/teammates/ui/webapi/GateKeeper.java
+++ b/src/main/java/teammates/ui/webapi/GateKeeper.java
@@ -466,10 +466,10 @@ void verifyOwnership(FeedbackResponseCommentAttributes frc, String feedbackParti
     void verifyOwnership(FeedbackResponseComment frc, String feedbackParticipant)
             throws UnauthorizedAccessException {
         verifyNotNull(frc, "feedback response comment");
-        verifyNotNull(frc.getGiver(), "feedback response comment giver");
+        verifyNotNull(frc.getGiver().getEmail(), "feedback response comment giver");
         verifyNotNull(feedbackParticipant, "comment giver");
 
-        if (!frc.getGiver().equals(feedbackParticipant)) {
+        if (!frc.getGiver().getEmail().equals(feedbackParticipant)) {
             throw new UnauthorizedAccessException("Comment [" + frc.getId() + "] is not accessible to "
                     + feedbackParticipant);
         }