I have the following mapping:
# A Parent {{Post}} entity
{code:java}
@Entity(name = "Post")
public class Post {
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long id;
private String name;
@OneToOne(cascade = CascadeType.ALL, mappedBy = "post", optional = false, fetch = FetchType.LAZY)
private PostDetails details;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public PostDetails getDetails() {
return details;
}
public void addDetails(PostDetails details) {
this.details = details;
details.setPost(this);
}
}
{code}
# A Child {{PostDetails}} entity:
{code:java}
@Entity(name = "PostDetails")
public class PostDetails {
@Id
private Long id;
private Date createdOn;
public PostDetails() {
createdOn = new Date();
}
@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id")
@MapsId
private Post post;
public Long getId() {
return id;
}
public void setPost(Post post) {
this.post = post;
}
}
{code}
When I try to cascade the persist operation from Post to PostDetails:
{code:java}
Post post = new Post();
post.setName("Hibernate Master Class");
post.addDetails(new PostDetails());
session.persist(post);
{code}
I get the following error:
{noformat}
org.hibernate.id.IdentifierGenerationException: null id generated for:class com.vladmihalcea.hibernate.masterclass.laboratory.cascade.CascadeLockTest$PostDetails
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:119)
at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:206)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:149)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:801)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:794)
at org.hibernate.engine.spi.CascadingActions$7.cascade(CascadingActions.java:314)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:350)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:293)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:118)
at org.hibernate.event.internal.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:432)
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:265)
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:194)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:206)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:149)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:75)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:811)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:784)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:789)
{noformat}
If I make the association as optional:
{code:java}
@OneToOne(cascade = CascadeType.ALL, mappedBy = "post", optional = true, fetch = FetchType.LAZY)
{code}
The persist works properly. |
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