I have two entities Post and PostDetails that are mapped as OneToOne with shared primary key, optional=false and id generator strategy set as IDENTITY/AUTO. When I try to persist the Post entity it fails with throwing exception.
Assuming we have following entities Post and PostDetails mapped as OneToOne with shared primary key, optional=false and id generator strategy set as IDENTITY/AUTO as below
{code:java}
@Entity
public class Post implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private long id;
@OneToOne(mappedBy="post", cascade = { CascadeType.ALL }, optional=false)
private PostDetails details;
public long getId() {
return id;
}
public PostDetails getDetails() {
return details;
}
public void addDetails(PostDetails details) {
this.details = details;
details.setPost(this);
}
public void deleteDetails() {
if(details !=null) {
details.setPost(null);
}
this.details = null;
}
}
@Entity
public class PostDetails implements Serializable {
@Id
@Column
private long id;
@OneToOne
@JoinColumn(name="id")
@MapsId
private Post post;
public long getId() {
return id;
}
public Post getPost() {
return post;
}
public void setPost(Post post) {
this.post = post;
}
}
{code}
When we execute the following test case to save the entities,
{code:java}
@Test
public void persistPost() {
Session session = sf.getCurrentSession();
session.getTransaction().begin();
Post post = new Post();
PostDetails details = new PostDetails();
post.addDetails(details);
session.persist(post);
session.beginTransaction().commit();
}
{code}
It fails to save and throws the following exception:
{code:java}
org.hibernate.id.IdentifierGenerationException: null id generated for:class PostDetails
{code} for IDENTITY
and
{code:java}
org.hibernate.exception.ConstraintViolationException: could not execute statement
{code} for AUTO
The same code works with both IDENTITY/AUTO if we change it to optional=true as below.
{code:java}
Changing
@OneToOne(mappedBy="post", cascade = { CascadeType.ALL }, optional=false)
to
@OneToOne(mappedBy="post", cascade = { CascadeType.ALL }, optional=true)
{code}
Although I tested only with DerbyDB and h2, I believe, issue can be replicated on other databases as well. |
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