cascade type save update in Hibernate

Question

I am using hibernate with JPA annotations for relationship mapping. I have three entities in my code User Group & User_Group

User & Group are in a ManyToMany relationship.

User_Group is a kinda bridge table but with some additional fields. So here is the modified mapping code.

User

@Entity
@Table(name = "USERS")
public class User {

@OneToMany(mappedBy = "user")
private Set<UserGroup> userGroups
}

Group

@Entity
@Table(name = "GROUPS")
public class Group {
@OneToMany(mappedBy = "group")
private Set<UserGroup> userGroups
}

UserGroup

@Entity
@Table(name = "USERS_GROUPS")
public class UserGroup {

@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "USER_ID")  
private User user;
@ManyToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "GROUP_ID")
private Group group;
}

When I set the user & group object to the usergroup & save it.

User user = new User("tommy", "ymmot", "[email protected]");
Group group = new Group("Coders");

UserGroup userGroup = new UserGroup();
userGroup.setGroup(group);
userGroup.setUser(user);
userGroup.setActivated(true);
userGroup.setRegisteredDate(new Date());

session.save(userGroup);

Things work fine. With CascadeType.ALL the group object & user object are updated too. But when I delete the userGroup object. The child object are deleted too.

Deletion of child objects is a strict no no.

There is no CascadeType.SAVE-UPDATE in JPA, which just does save or update but no delete. How do I achieve this.

If I remove the CascadeType.ALL from the mapping the child objects don't get updated & I need them to be updated.

Answer 1

SAVE_UPDATE is for save(), update(), and saveOrUpdate(), which are 3 Hibernate-proprietary methods. JPA only has persist() and merge(). So, if you want to use cascading on Hibernate-proprietary methods, you'll need to use Hibernate-proprietary annotations. In this case, Cascade.

Or you could stop using the Hibernate Session, and use the standard JPA API instead.