org.hibernate.AnnotationException: No identifier specified for entity

[Leandro Coutinho]

I have this table:

create table QuestionTest ( question_id int, test_id int, primary key(question_id, test_id), foreign key(question_id) references Question(id), foreign key(test_id) references Test(id) );
The QuestionTest class only has the mapping:
@ManyToOne
private Question question;
@ManyToOne
private Test test;

I know that the problem can be solved creating an id field, but I don't want to do it. I want the primary key to be the composite key.
Is it possible? How can I do this?

[Muhammad Ramahy]

If you're using Hibernate you can put @Id on both of attributes
this will make it a composite.However, I don't think that you should map a relation table as an entity.

[Repala Madhu]

You can do this in the following way.


public class NameId implements Serializable
{
protected String name;
protected int type;
protected String neName;

//Getters and Setters follows
}


@Entity
@Table(name = "NAME_")
@IdClass(NameId.class)
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
public class Name Serializable
{
@Id
protected String name;
@Id
protected int type;

protected String MOType;
@Id
protected String neName;
public Name()
{

}
//Getters and Setters follows
}

[Leandro Coutinho]

Muhammad Ramahy wrote:If you're using Hibernate you can put @Id on both of attributes

If I put @Id in both a get this.
org.hibernate.AnnotationException: mappedBy reference an unknown target entity property: questionapp.model.QuestionTest.test in questionapp.model.Test.questionsTests

Muhammad Ramahy wrote:However, I don't think that you should map a relation table as an entity.

What do you do then?

[Leandro Coutinho]

Repala Madhu wrote:You can do this in the following way.

Thanks for mention @IdClass
I followed this tutorial http://www.ibm.com/developerworks/java/library/os-hibernatejpa/index.html
But it's not working for me. I don't know what I'm missing.

When I try to save

Question q = daoQuestion.read(Integer.valueOf(strQuestionId));
QuestionTest qt = new QuestionTest(new QuestionTestPK(q, test));
qt.setQuestion(q);
qt.setTest(test);
daoQuestioTest.save(qt);    // <<<-----------

I get this error java.lang.ClassCastException: questionapp.model.QuestionTestPK cannot be cast to java.lang.Integer

[Muhammad Ramahy]

take a look at this example: http://www.vaannila.com/hibernate/hibernate-example/hibernate-mapping-many-to-one-using-annotations-1.html