2つのテーブル間に1対多の関係があります。スプリングブートJPAが動作しません。

Question

2つのテーブルコーステーブルとゲームテーブルを作成しようとしています。コースには多くのゲームが含まれています。ゲームは1つのコースにのみ割り当てられます。 私は次のように春のブート時にそれを行うには、エンティティを定義している：

コースエンティティ：

package play_and_learn.model; 

import java.util.ArrayList; 
import java.util.List; 

import javax.persistence.*; 

@Entity 
@Table(name = "courses") 
public class Course { 
@Id 
@GeneratedValue(strategy = GenerationType.AUTO) 
private int courseId; 
private String courseName; 
private String courseDescription; 
private String creatorTeacherUsername; 

@OneToMany(mappedBy = "course", cascade = CascadeType.ALL) 
private List<Game> courseGames; 

public Course(String courseName, String courseDescription 
     , String creatorTeacherUsername, List<Game> courseGames) { 
    super(); 
    this.courseName = courseName; 
    this.courseDescription = courseDescription; 
    this.creatorTeacherUsername = creatorTeacherUsername; 
    this.courseGames = courseGames; 
} 

public Course(String courseName, String courseDescription, String creatorTeacherUsername) { 
    super(); 
    this.courseName = courseName; 
    this.courseDescription = courseDescription; 
    this.creatorTeacherUsername = creatorTeacherUsername; 
    this.courseGames = new ArrayList<Game>(); 
} 

public Course(String courseName, String description) { 
    super(); 
    this.courseName = courseName; 
    this.courseDescription = description; 
    this.creatorTeacherUsername = ""; 
    this.courseGames = new ArrayList<Game>(); 
} 

public Course() { 
    super(); 
    this.courseName = ""; 
    this.courseDescription = ""; 
    this.courseGames = new ArrayList<>(); 
} 

public void addGame(Game game) { 
    courseGames.add(game); 
} 

public int getCourseId() { 
    return courseId; 
} 

public void setCourseId(int courseId) { 
    this.courseId = courseId; 
} 

public String getCourseName() { 
    return courseName; 
} 

public void setCourseName(String courseName) { 
    this.courseName = courseName; 
} 

public String getCourseDescription() { 
    return courseDescription; 
} 

public void setCourseDescription(String courseDescription) { 
    this.courseDescription = courseDescription; 
} 

public String getCreatorTeacherUsername() { 
    return creatorTeacherUsername; 
} 

public void setCreatorTeacherUsername(String creatorTeacherUsername) { 
    this.creatorTeacherUsername = creatorTeacherUsername; 
} 

public List<Game> getCourseGames() { 
    return courseGames; 
} 

public void setCourseGames(List<Game> courseGames) { 
    this.courseGames = courseGames; 
} 

public Game getGameByID(int gameID) { 
    for (Game game : courseGames) { 
     if (game.getGameId() == gameID) { 
      return game; 
     } 
    } 
    return null; 
} 



// @Override 
// public String toString() { 
//  return "Course [courseId=" + courseId + ", courseName=" + courseName 
+ ", courseDescription=" 
//    + courseDescription + ", courseGames=" + courseGames + "]"; 
// } 


} 

ゲームエンティティ

package play_and_learn.model; 

import java.util.ArrayList; 
import java.util.List; 

import javax.persistence.*; 

@Entity 
@Table(name = "games") 
public class Game { 
@Id 
@GeneratedValue(strategy = GenerationType.AUTO) 
private int gameID; 
private String name; 
private String description; 
private String creatorTeacherUsername; 
private String gameType; // MCQ , True & False , etc. 

protected int numOfQuestions = 0; 

@ManyToOne 
@JoinColumn(name = "courseId") 
private Course course; // database related field 

@OneToMany(mappedBy = "q_id", cascade = CascadeType.ALL) 
protected List<Question> questions; 

public Game() { 
    name=""; 
    description=""; 
    creatorTeacherUsername = ""; 
    gameType = ""; 
    numOfQuestions = 0; 
    questions = new ArrayList<>(); 
} 

public Game(String name, String description, String creatorTeacherUsername 
     , String gameType, int numnumOfQuestions) { 
    this.name = name; 
    this.description = description; 
    this.creatorTeacherUsername = creatorTeacherUsername; 
    this.gameType = gameType; 
    this.numOfQuestions = numnumOfQuestions; 
    questions = new ArrayList<>(); 
} 


public String getGameType() { 
    return gameType; 
} 

public void setGameType(String gameType) { 
    this.gameType = gameType; 
} 

public String getName() { 
    return name; 
} 

public void setName(String name) { 
    this.name = name; 
} 

public String getDescription() { 
    return description; 
} 

public void setDescription(String description) { 
    this.description = description; 
} 

public int getGameId() { 
    return gameID; 
} 

public void setGameId(int id) { 
    this.gameID = id; 
} 

public String getCreatorTeacherUsername() { 
    return creatorTeacherUsername; 
} 

public void setCreatorTeacherUsername(String creatorTeacherUsername) { 
    this.creatorTeacherUsername = creatorTeacherUsername; 
} 

public int getNumOfQuestions() { 
    return numOfQuestions; 
} 

public void setNumOfQuestions(int numOfQuestions) { 
    this.numOfQuestions = numOfQuestions; 
} 

public List<Question> getQuestions() { 
    return questions; 
} 

public void setQuestions(List<Question> questions) { 
    this.questions = questions; 
} 

public void addQuestion(String qBody, String theRightAnswer, String ... answers) { 
    Question q = new Question(); 

    q.setqBody(qBody); 
    q.setAnswer1(answers[0]); 
    q.setAnswer2(answers[1]); 
    q.setAnswer3(answers[2]); 
    q.setAnswer4(answers[3]); 
    q.setTheRighAnswer(theRightAnswer); 

    questions.add(q);  
} 

public void addQuestion(Question question) {   
    questions.add(question);   
} 


// @Override 
// public String toString() { 
//  return "Game [gameID=" + gameID + ", name=" + name + ", description=" + 
description 
//    + ", creatorTeacherUsername=" + creatorTeacherUsername + ", 
gameType=" + gameType + ", numOfQuestions=" 
//    + numOfQuestions + ", questions=" + questions + "]"; 
// } 


} 

私はいつも私のコースの内部には、ゲームを取得していないが：（Course_IDに画像のように常にヌルです） MySql Query

私のエンティティで何が間違っていますか？

Answer 1

逆の関係も設定します。つまり、関係に追加されるゲームごとにcourseIdを設定します。

public class Course{ 
... 
public void addGame(Game game) { 
    courseGames.add(game); 
    game.setCourse(this); 
} 

コンストラクタと同じです。