[Fix] 엔티티간 양방향 연관관계 매핑 정상화

src/main/java/com/_1/spring_rest_api/converter/QuestionGenerationConverter.java

@@ -2,10 +2,16 @@
 
 import com._1.spring_rest_api.api.dto.QuestionDto;
 import com._1.spring_rest_api.entity.Question;
+import com._1.spring_rest_api.entity.Week;
 import com._1.spring_rest_api.repository.WeekRepository;
+import jakarta.persistence.EntityNotFoundException;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Component;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
 /**
  * AI 생성 질문 DTO와 Question 엔티티 간의 변환을 담당하는 컨버터
  */
@@ -39,13 +45,16 @@ public Question toEntity(QuestionDto dto) {
                 .build();
     }
 
-    /**
-     * AI가 생성한 질문 DTO를 특정 주차의 Question 엔티티로 변환
-     *
-     * @param dto    질문 DTO
-     * @param weekId 주차 ID
-     * @return 주차에 연결된 Question 엔티티
-     */
+    public List<Question> createQuestionsForWeek(List<QuestionDto> dtos, Long weekId) {
+        if (dtos == null || dtos.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        return dtos.stream()
+                .map(dto -> createQuestionForWeek(dto, weekId))
+                .collect(Collectors.toList());
+    }
+
     public Question createQuestionForWeek(QuestionDto dto, Long weekId) {
         if (dto == null) {
             return null;
@@ -54,9 +63,14 @@ public Question createQuestionForWeek(QuestionDto dto, Long weekId) {
         Question question = toEntity(dto);
 
         if (weekId != null) {
-            weekRepository.findById(weekId).ifPresent(question::changeWeek);
+            Week week = weekRepository.findById(weekId)
+                    .orElseThrow(() -> new EntityNotFoundException("Week not found with id: " + weekId));
+
+            week.addQuestion(question);
         }
 
         return question;
     }
+
+
 }

src/main/java/com/_1/spring_rest_api/entity/Course.java

@@ -62,14 +62,6 @@ public void changeCreator(User creator) {
         }
     }
 
-
-    public Course(User creator, String title, String description) {
-        this.creator = creator;
-        this.title = title;
-        this.description = description;
-        this.weeks = new ArrayList<>();
-    }
-
     public Course(Long id, User creator, String title, String description) {
         this.id = id;
         this.creator = creator;

src/main/java/com/_1/spring_rest_api/entity/CustomQuiz.java

@@ -91,7 +91,7 @@ public void addQuestion(Question question) {
         }
 
         // 정적 팩토리 메서드를 통해 매핑 생성 및 양방향 연관관계 설정
-        QuizQuestionMapping mapping = QuizQuestionMapping.create(this, question);
+        QuizQuestionMapping.create(this, question);
 
         // 질문 수 증가
         this.updateTotalQuestions(this.totalQuestions + 1);

src/main/java/com/_1/spring_rest_api/entity/QuizSession.java

@@ -37,6 +37,22 @@ public class QuizSession extends BaseTimeEntity {
 
     private LocalDateTime completedAt;
 
+    // User와 QuizSession 간의 양방향 연관관계 메서드
+    public void changUser(User user) {
+        this.user = user;
+        if (user != null && !user.getQuizSessions().contains(this)) {
+            user.getQuizSessions().add(this);
+        }
+    }
+
+    // CustomQuiz와 QuizSession 간의 양방향 연관관계 메서드
+    public void changeQuiz(CustomQuiz quiz) {
+        this.quiz = quiz;
+        if (quiz != null && !quiz.getQuizSessions().contains(this)) {
+            quiz.getQuizSessions().add(this);
+        }
+    }
+
     public static QuizSession create(User user, CustomQuiz quiz) {
         if (user == null) {
             throw new IllegalArgumentException("사용자는 null이 될 수 없습니다");
@@ -53,6 +69,29 @@ public static QuizSession create(User user, CustomQuiz quiz) {
                 .build();
     }
 
+    public UserAnswer createAnswer(String userAnswerText) {
+        Question currentQuestion = getCurrentQuestion();
+        if (currentQuestion == null) {
+            throw new IllegalStateException("세션에 현재 질문이 없습니다");
+        }
+
+        boolean isCorrect = currentQuestion.isCorrectAnswer(userAnswerText);
+
+        UserAnswer userAnswer = UserAnswer.builder()
+                .user(this.user)
+                .question(currentQuestion)
+                .userAnswer(userAnswerText)
+                .isCorrect(isCorrect)
+                .attemptCount(1)
+                .answeredAt(LocalDateTime.now())
+                .build();
+
+        currentQuestion.addUserAnswer(userAnswer);
+        this.user.addUserAnswer(userAnswer);
+
+        return userAnswer;
+    }
+
     public void moveToNextQuestion() {
         this.currentQuestionIndex++;
     }
@@ -86,38 +125,4 @@ public Question getNextQuestion() {
     public boolean isComplete() {
         return this.currentQuestionIndex >= this.quiz.getQuizQuestionMappings().size();
     }
-
-    public UserAnswer createAnswer(String userAnswerText) {
-        Question currentQuestion = getCurrentQuestion();
-        if (currentQuestion == null) {
-            throw new IllegalStateException("세션에 현재 질문이 없습니다");
-        }
-
-        boolean isCorrect = currentQuestion.isCorrectAnswer(userAnswerText);
-
-        return UserAnswer.builder()
-                .user(this.user)
-                .question(currentQuestion)
-                .userAnswer(userAnswerText)
-                .isCorrect(isCorrect)
-                .attemptCount(1)
-                .answeredAt(LocalDateTime.now())
-                .build();
-    }
-
-    // User와 QuizSession 간의 양방향 연관관계 메서드
-    public void changeUser(User user) {
-        this.user = user;
-        if (user != null && !user.getQuizSessions().contains(this)) {
-            user.getQuizSessions().add(this);
-        }
-    }
-
-    // CustomQuiz와 QuizSession 간의 양방향 연관관계 메서드
-    public void changeQuiz(CustomQuiz quiz) {
-        this.quiz = quiz;
-        if (quiz != null && !quiz.getQuizSessions().contains(this)) {
-            quiz.getQuizSessions().add(this);
-        }
-    }
 }

src/main/java/com/_1/spring_rest_api/entity/User.java

@@ -45,11 +45,11 @@ public class User extends BaseTimeEntity {
     private List<UserAnswer> userAnswers = new ArrayList<>();
 
     // User와 UserKakao 간의 양방향 연관관계 메서드
-    public void linkWithKakao(UserKakao userKakao) {
+    public void changeUserKakao(UserKakao userKakao) {
         this.userKakao = userKakao;
         // userKakao의 user 필드가 this가 아닌 경우에만 설정
         if (userKakao.getUser() != this) {
-            userKakao.linkWithUser(this);
+            userKakao.changeUser(this);
         }
     }
 
@@ -87,14 +87,14 @@ public void removeCourse(Course course) {
     public void addQuizSession(QuizSession session) {
         this.quizSessions.add(session);
         if (session.getUser() != this) {
-            session.changeUser(this);
+            session.changUser(this);
         }
     }
 
     public void removeQuizSession(QuizSession session) {
         this.quizSessions.remove(session);
         if (session.getUser() == this) {
-            session.changeUser(null);
+            session.changUser(null);
         }
     }
 
@@ -121,10 +121,6 @@ public void updateName(String name) {
         this.name = name;
     }
 
-    public void updateUserKakao(UserKakao userKakao) {
-        this.userKakao = userKakao;
-    }
-
     public static User createKakaoUser(String email, String name) {
         if (email == null || email.isEmpty()) {
             throw new IllegalArgumentException("이메일은 필수 값입니다.");

src/main/java/com/_1/spring_rest_api/entity/UserKakao.java

@@ -39,11 +39,11 @@ public class UserKakao extends BaseTimeEntity {
     private LocalDateTime tokenExpiresAt;
 
     // User와 UserKakao 간의 양방향 연관관계 메서드
-    public void linkWithUser(User user) {
+    public void changeUser(User user) {
         this.user = user;
         // user의 userKakao 필드가 this가 아닌 경우에만 설정
         if (user.getUserKakao() != this) {
-            user.linkWithKakao(this);
+            user.changeUserKakao(this);
         }
     }
 
@@ -65,12 +65,11 @@ public static UserKakao createKakaoAccountLink(User user, String kakaoId) {
         }
 
         UserKakao userKakao = UserKakao.builder()
-                .user(user)
                 .kakaoAccountId(kakaoId)
                 .build();
 
         // 양방향 연관관계 설정
-        user.updateUserKakao(userKakao);
+        userKakao.changeUser(user);
 
         return userKakao;
     }

src/main/java/com/_1/spring_rest_api/repository/CustomQuizRepository.java

@@ -6,11 +6,26 @@
 import org.springframework.data.repository.query.Param;
 
 import java.util.List;
+import java.util.Optional;
 
 
 public interface CustomQuizRepository extends JpaRepository<CustomQuiz, Long> {
 
     @Query("SELECT q FROM CustomQuiz q WHERE q.creator.id = :creatorId ORDER BY q.createAt DESC")
     List<CustomQuiz> findAllByCreatorId(@Param("creatorId") Long creatorId);
 
+    @Query("SELECT DISTINCT q FROM CustomQuiz q " +
+            "LEFT JOIN FETCH q.creator " +
+            "LEFT JOIN FETCH q.quizQuestionMappings qm " +
+            "LEFT JOIN FETCH qm.question " +
+            "WHERE q.id = :quizId")
+    Optional<CustomQuiz> findByIdWithQuestions(@Param("quizId") Long quizId);
+
+    @Query("SELECT DISTINCT q FROM CustomQuiz q " +
+            "LEFT JOIN FETCH q.quizWeekMappings wm " +
+            "LEFT JOIN FETCH wm.week w " +
+            "LEFT JOIN FETCH w.course " +
+            "WHERE q.id = :quizId")
+    Optional<CustomQuiz> findByIdWithWeeks(@Param("quizId") Long quizId);
+
 }

src/main/java/com/_1/spring_rest_api/service/CourseService.java

@@ -4,6 +4,7 @@
 import com._1.spring_rest_api.entity.User;
 import com._1.spring_rest_api.entity.Week;
 import com._1.spring_rest_api.repository.CourseRepository;
+import com._1.spring_rest_api.repository.UserRepository;
 import jakarta.persistence.EntityNotFoundException;
 import lombok.RequiredArgsConstructor;
 import org.springframework.stereotype.Service;
@@ -17,11 +18,21 @@
 public class CourseService {
 
     private final CourseRepository courseRepository;
+    private final UserRepository userRepository;
 
-    public Long createCourse(
-            Long userId, String title, String description) {
-        // User entity 조회 후 넣어야 함. - 임시로 User() 사용
-        Course course = courseRepository.save(new Course(new User(userId), title, description));
+    public Long createCourse(Long userId, String title, String description) {
+        User user = userRepository.findById(userId)
+                .orElseThrow(() -> new EntityNotFoundException("User not found with id: " + userId));
+
+        Course course = Course.builder()
+                .creator(user)
+                .title(title)
+                .description(description)
+                .build();
+
+        user.addCourse(course);
+
+        Course savedCourse = courseRepository.save(course);
         return course.getId();
     }
 

src/main/java/com/_1/spring_rest_api/service/QuestionCommandServiceImpl.java

@@ -41,14 +41,13 @@ public List<Long> generateAndSaveQuestions(Long weekId, int minQuestionCount) {
         List<QuestionDto> generatedQuestions =
                 claudeService.generateQuestionsFromWeekTexts(weekId, minQuestionCount);
 
-        // 생성된 질문을 저장 (컨버터 활용)
-        List<Long> savedQuestionIds = generatedQuestions.stream()
-                .map(dto -> questionGenerationConverter.createQuestionForWeek(dto, weekId))
+        List<Question> questions = questionGenerationConverter.createQuestionsForWeek(
+                generatedQuestions, weekId);
+
+        return questions.stream()
                 .map(questionRepository::save)
                 .map(Question::getId)
                 .collect(Collectors.toList());
-
-        return savedQuestionIds;
     }
 
 

src/main/java/com/_1/spring_rest_api/service/QuizCommandServiceImpl.java

@@ -65,15 +65,11 @@ public Long startQuizSession(Long quizId, Long userId) {
                 .orElseThrow(() -> new EntityNotFoundException("User not found with id: " + userId));
 
         // 새 퀴즈 세션 생성
-        QuizSession session = QuizSession.builder()
-                .user(user)
-                .quiz(quiz)
-                .currentQuestionIndex(0) // 첫 번째 질문부터 시작
-                .build();
+        QuizSession session = QuizSession.create(user, quiz);
 
         // 양방향 연관관계 설정
-        session.changeUser(user);
-        session.changeQuiz(quiz);
+        user.addQuizSession(session);
+        quiz.addQuizSession(session);
 
         // 저장 및 ID 반환
         QuizSession savedSession = quizSessionRepository.save(session);
@@ -97,10 +93,7 @@ private void connectWeeksToQuiz(List<Long> weekIds, CustomQuiz quiz) {
                     .build();
 
             // 양방향 연관관계 설정
-            mapping.changeQuiz(quiz);
-            mapping.changeWeek(week);
-
-            quizWeekMappingRepository.save(mapping);
+            quiz.addQuizWeekMapping(mapping);
         }
     }
 
@@ -124,8 +117,6 @@ private void processQuestions(CreateQuizRequest request, CustomQuiz quiz) {
             quiz.addQuestion(question);
         }
 
-        // 총 질문 수 업데이트 및 저장
-        quiz.updateTotalQuestions(questions.size());
         customQuizRepository.save(quiz);
     }
 

src/main/java/com/_1/spring_rest_api/service/QuizQueryServiceImpl.java

@@ -29,9 +29,11 @@ public List<QuizSummaryResponse> getQuizzesByUserId(Long userId) {
 
     @Override
     public QuizDetailResponse getQuizDetail(Long quizId) {
-        CustomQuiz quiz = customQuizRepository.findById(quizId)
+        CustomQuiz quiz = customQuizRepository.findByIdWithQuestions(quizId)
                 .orElseThrow(() -> new EntityNotFoundException("Quiz not found with id: " + quizId));
 
+        customQuizRepository.findByIdWithWeeks(quizId);
+
         return convertToDetailResponse(quiz);
     }