Latest posts for the topic "Create a relationship for Many-to-Many table."

Create a relationship for Many-to-Many table.

jvence — Thu, 16 Nov 2006 07:58:55

Basically, I have two entities that have a many-to-many relationship so 3 tables are created in the DB. I can insert a record for my 2 entities using the generated POJOs but how do I create a relationship (a record in the many to many table)? The Pojo doesn't seem to provide anyway to create this relationship.
Thanks

Re:Create a relationship for Many-to-Many table.

Jick — Thu, 16 Nov 2006 18:07:24

Hi jvence,

I guess that you want to add records to the Link table (the extra table created by the many-to-many relationship). Actually, there should not be a class for the Link table. You just need to use the POJO as usual, and the underlying persistence tier will do the mapping for you - create the records to the appropriate table in the database.

Hope this helps. Please feel free to let me know if there are any questions.

Best regards,
Jick

Re:Create a relationship for Many-to-Many table.

jvence — Thu, 16 Nov 2006 22:23:14

Yes, I'm trying to add a record to the Link table. There's nothing in the individual POJOs that would let me create an association in the Link table (except perhaps the getORMxxx (which returns a set of the association), then adding to this set and using setORMxxx to save it back. BTW the functions that deals with retrieving/setting the set of association are private.
Do you have any example on how to do this?
Jean

Jick wrote:

Re:Create a relationship for Many-to-Many table.

Jick — Fri, 17 Nov 2006 11:20:47

Dear jvence,

Please check if the following code sample could help:

Code:

 
 //entity EA
 demo.EA ldemoEA = new demo.EA();
 //...
 			
 //entity EB
 demo.EB ldemoEB = new demo.EB();
 //...
 
 //link entity
 demo.EA_Entity ldemoEA_Entity = new demo.EA_Entity();
 //...
 ldemoEA_Entity.setEAidA(ldemoEA);
 ldemoEA_Entity.setEBidB(ldemoEB);
 
 //save objects
 orm.P25PersistentManager.instance().getSession().save(ldemoEA);
 orm.P25PersistentManager.instance().getSession().save(ldemoEB);
 orm.P25PersistentManager.instance().getSession().save(ldemoEA_Entity);

Best regards,
Jick