Я делаю простое упражнение, чтобы выучить JPA. Когда я пытаюсь удалить объект типа Пользователь , который имеет коллекцию другого объекта Счет (отмечен @OneToMany), я получаю эту ошибку:
java.sql.SQLIntegrityConstraintViolationException: Column 'user' cannot be null
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:117)
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:122)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1092)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdateInternal(ClientPreparedStatement.java:1040)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeLargeUpdate(ClientPreparedStatement.java:1347)
at com.mysql.cj.jdbc.ClientPreparedStatement.executeUpdate(ClientPreparedStatement.java:1025)
at org.hibernate.engine.jdbc.internal.ResultSetReturnImpl.executeUpdate(ResultSetReturnImpl.java:197)
... 20 more
Это мои классы:
Пользователь. java
@Entity
@Table(name = "user")
public class User
{
@Id
private Integer id;
@NotNull
@Size(max = 20)
private String name;
@OneToMany(fetch = FetchType.LAZY,cascade = CascadeType.ALL,orphanRemoval = true)
@JoinColumn(name = "user")
private Collection<Score> scores;
public User() {
}
public User(Integer id, String name, Collection<Score> scores) {
this.id = id;
this.name = name;
this.scores = scores;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Collection<Score> getScores() {
return scores;
}
public void setScores(Collection<Score> scores) {
this.scores = scores;
}
}
Оценка. java
@Entity
@Table(name = "score")
public class Score
{
@EmbeddedId
private ScoreId id;
@NotNull
private Integer points;
public Score() {
}
public Score(ScoreId id, Integer points) {
this.id = id;
this.points = points;
}
public ScoreId getId() {
return id;
}
public void setId(ScoreId id) {
this.id = id;
}
public Integer getPoints() {
return points;
}
public void setPoints(Integer points) {
this.points = points;
}
@Override
public boolean equals(Object obj) {
if (obj!=null && getClass()==obj.getClass())
{
Score other = (Score) obj;
return Objects.equals(id, other.id) && Objects.equals(points,other.points);
}
return false;
}
@Override
public int hashCode() {
return id!=null ? points!=null ? id.hashCode()+points.hashCode() : 0 : 0;
}
@Override
public String toString() {
return getClass().getName() + "[id =" + id + ",points = " + points;
}
}
ScoreId. java
@Embeddable
public class ScoreId implements Serializable
{
private Integer user;
@Enumerated(EnumType.STRING)
private Game game;
public ScoreId() {
}
public ScoreId(Integer user, Game game) {
this.user = user;
this.game = game;
}
public Integer getUser() {
return user;
}
public void setUser(Integer user) {
this.user = user;
}
public Game getGame() {
return game;
}
public void setGame(Game game) {
this.game = game;
}
public enum Game
{
HANGMAN,
TRIS
}
@Override
public boolean equals(Object obj) {
if (obj!=null && getClass()==obj.getClass())
{
ScoreId other = (ScoreId) obj;
return Objects.equals(user,other.user) && game==other.game;
}
return false;
}
@Override
public int hashCode()
{
return user!=null ? game!=null ? user.hashCode()+game.hashCode() : 0 : 0;
}
@Override
public String toString() {
return getClass().getName() + "[user = " + user + ",game = " + game + "]";
}
}
Main. java
public class Main {
public static void main(String[] args) {
EntityManagerFactory factory = Persistence.createEntityManagerFactory("UserJPA");
EntityManager em = factory.createEntityManager();
EntityTransaction et = em.getTransaction();
User demetrio = em.createQuery("SELECT u FROM User u WHERE u.name = 'Demetrio'",User.class).getSingleResult();
et.begin();
em.remove(demetrio);
et.commit();
em.close();
factory.close();
}
}
Это скрипт для генерации db:
CREATE TABLE `user`
(
id INT PRIMARY KEY,
`name` VARCHAR(20) UNIQUE NOT NULL
);
CREATE TABLE score
(
`user` INT,
game ENUM("HANGMAN","TRIS"),
points INT UNSIGNED NOT NULL,
PRIMARY KEY(`user`,game),
FOREIGN KEY (`user`) REFERENCES `user`(id)
ON UPDATE CASCADE
ON DELETE CASCADE
)
Я использую Hibernate в качестве реализации JPA. Я искал решение, но ничего не нашел. Может я что то не так делаю. Вы можете мне помочь?