[feat/#21] 문항 조횟 시 새끼문항 lazy로딩

Author: sejoon00

src/main/java/com/moplus/moplus_server/domain/problem/domain/Problem.java

@@ -6,6 +6,7 @@
 import jakarta.persistence.Column;
 import jakarta.persistence.ElementCollection;
 import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
 import jakarta.persistence.GeneratedValue;
 import jakarta.persistence.GenerationType;
 import jakarta.persistence.Id;
@@ -41,7 +42,7 @@ public class Problem extends BaseEntity {
     @CollectionTable(name = "problem_concept", joinColumns = @JoinColumn(name = "concept_tag_id"))
     Set<Long> conceptTagIds;
 
-    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true)
+    @OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, fetch = FetchType.LAZY)
     @JoinColumn(name = "problem_id")
     private List<ChildProblem> childProblems = new ArrayList<>();