diff --git a/backend/src/main/java/com/edufocus/edufocus/board/entity/vo/Board.java b/backend/src/main/java/com/edufocus/edufocus/board/entity/vo/Board.java
index f7ee473..2cca933 100644
--- a/backend/src/main/java/com/edufocus/edufocus/board/entity/vo/Board.java
+++ b/backend/src/main/java/com/edufocus/edufocus/board/entity/vo/Board.java
@@ -9,6 +9,8 @@ import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import jakarta.persistence.*;
 import lombok.*;
 import org.hibernate.annotations.CreationTimestamp;
+import org.hibernate.annotations.OnDelete;
+import org.hibernate.annotations.OnDeleteAction;
 import org.hibernate.annotations.UpdateTimestamp;
 import org.springframework.data.annotation.CreatedDate;
 import org.springframework.data.annotation.LastModifiedDate;
@@ -59,9 +61,9 @@ public class Board {
 
     @ManyToOne(fetch = FetchType.LAZY)
     @JoinColumn(name = "lecture_id")
+    @OnDelete(action = OnDeleteAction.CASCADE)
     private Lecture lecture;
 
-
     @OneToMany(mappedBy = "board", cascade = CascadeType.ALL)
     private List<Comment> comments;
 
diff --git a/backend/src/main/java/com/edufocus/edufocus/report/entity/vo/ReportSet.java b/backend/src/main/java/com/edufocus/edufocus/report/entity/vo/ReportSet.java
index fb293ec..ab10529 100644
--- a/backend/src/main/java/com/edufocus/edufocus/report/entity/vo/ReportSet.java
+++ b/backend/src/main/java/com/edufocus/edufocus/report/entity/vo/ReportSet.java
@@ -5,10 +5,9 @@ import com.edufocus.edufocus.quiz.entity.QuizSet;
 import com.edufocus.edufocus.report.entity.dto.ReportSetResponse;
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import jakarta.persistence.*;
+import jakarta.persistence.CascadeType;
 import lombok.*;
-import org.hibernate.annotations.ColumnDefault;
-import org.hibernate.annotations.CreationTimestamp;
-import org.hibernate.annotations.GenericGenerator;
+import org.hibernate.annotations.*;
 import org.springframework.data.annotation.CreatedDate;
 import org.springframework.data.jpa.domain.support.AuditingEntityListener;
 
@@ -46,6 +45,7 @@ public class ReportSet {
 
     @ManyToOne
     @JoinColumn(name = "lecture_id")
+    @OnDelete(action = OnDeleteAction.CASCADE)
     private Lecture lecture;
 
     @ManyToOne