Question

我的一对多映射存在问题两个表问题（PK（id），文本）和答案（PK（id，questionId），文本）
在我的应用程序中，我以只读模式使用此表我想要定义这些表之间的关系

@Entity
@Table(name = "QUESTIONS")
public class Question {
    @Id
    @Column(name = "QUESTIONID")
    private long questionId;
    @Column(name = "QUESTIONTEXT")
    private String questionText;
    @OneToMany(mappedBy = "question", fetch = FetchType.EAGER)
    private List<Answer> answers;         
}

@Entity
@Table(name = "ANSWERS")
public class Answer implements Serializable {

    @EmbeddedId
    private AnswerPK AnswerPK;
    @Column(name = "ANSWERTEXT")
    private String answerText;
    @ManyToOne
    @JoinColumn(name = "QUESTIONID", insertable = false, updatable = false)
    private Question question;
}

@Embeddable
public class AnswerPK implements Serializable {
    @Column(name = "QUESTIONID")
    private long questionId;
    @Column(name = "ANSWERID")
    private int answerId;
}

但是当我使用@JoinColumn时会创建外键。
当我尝试填充表格时，我得到了异常

java.sql.SQLIntegrityConstraintViolationException: ORA-02292: integrity constraint (ZODI.FK_ANSWERS_QUESTIONID) violated - child record found

Answer 1

尝试将insertable / updatable = false放入EmbeddedId，而不是JoinColumn。

另外考虑不使用EmbeddedId，而是使用IdClass，然后您只需要使用@Id注释answerId和问题。或者甚至更好，从主键中删除questionId并确保answerId是唯一的（例如使其成为生成的id）。

请参阅， http://en.wikibooks.org/wiki/Java_Persistence/Identity_and_Sequencing#Primary_Keys_through_OneToOne_and_ManyToOne_Relationships

OneToMany和复杂的PK

1 个答案: