Question

I have problem with one-to-many mapping.
Two tables questions(PK(id), text) and answers(PK(id, questionId), text)
In my app I use this tables in read-only mode.
I want define relations between this tables

@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;
}

But when I use @JoinColumn will be created foreign key.
And when I try to fill tables, I got exception

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

Answer 1

Try putting the insertable/updatable=false in the EmbeddedId, not the JoinColumn.

Also consider not using an EmbeddedId, instead use a IdClass, then you just need to annotate the answerId and the question with @Id. Or even better, remove the questionId from the primary key and ensure answerId is unique (such as making it a generated id).

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