Re: [ebean] OneToOne key generation

[Rob Bygrave]

>> So is it possible to have the 'user_id' of the child Settings object 'automagically' get the same 'user_id' of it's newly created parent User?

The same Primary Key value?  No, there is no feature to support that.

>> would converting to a SecondaryTable strategy be simpler/"better"?

Generally I expect a normal 1 to 1 relationship ... with a foreign key that also has a unique constraint on it.

On 11 May 2013 06:33, Brannon Smith <gbs...@gmail.com> wrote:

So we have a MySQL 'users' table with an Auto-Increment PK called 'user_id' mapped to 'User' class.

We would like to add a 'user_settings' table mapped to 'Setting' class in a OneToOne relationship to 'User' with a shared PK, also called 'user_id' (non A-I this time) on that table.

So is it possible to have the 'user_id' of the child Settings object 'automagically' get the same 'user_id' of it's newly created parent User? Or does this require manual intervention?

IIRC, Hibernate had a special generator that could take care of this. 

If this is not possible, would converting to a SecondaryTable strategy be simpler/"better"?

If all else fails, I suppose we could just fold the settings right into the user, but I was hoping to keep those separate.

-GBS

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[Brannon Smith]

I guess I see a shared PK as no less normal than a unique FK in such a case. ;-)

But say I could get SecondaryTable to work (more on that in a moment) wouldn't that automatically set a shared PK on the second table? In other words, wouldn't the behavior I asked about that does not exist with OneToOne, work in the context of SecondaryTable?

After my initial post, I tried to reimplement with SecondaryTable:

@Entity

@Table(name = "users")

@SecondaryTable(name = "user_settings")

public class User extends Model

{

   @Id

   @Column(name = "user_id")

   public Long id;

   @Column(unique = true)

   public String username;

   @Column(table="user_settings")

   private String timeZone;

   // [...other stuff...]

}

But I get this stack trace, even though both the users and user_settings table exist each with a user_id column (auto-inc on users):

[error] c.a.e.s.d.BeanDescriptorManager - Error in deployment

java.lang.NullPointerException: null

at com.avaje.ebeaninternal.server.deploy.meta.DeployBeanDescriptor.findJoinToTable(DeployBeanDescriptor.java:899) ~[avaje-ebeanorm-server.jar:na]

at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.secondaryPropsJoins(BeanDescriptorManager.java:658) ~[avaje-ebeanorm-server.jar:na]

at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.readEntityRelationships(BeanDescriptorManager.java:628) ~[avaje-ebeanorm-server.jar:na]

at com.avaje.ebeaninternal.server.deploy.BeanDescriptorManager.deploy(BeanDescriptorManager.java:256) ~[avaje-ebeanorm-server.jar:na]

        [snip]

Have I left out some necessary config?

-GBS