[CAY-1348] Allow to-many relationships from non-pk columns

• Type: Improvement
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 3.1M1
• Fix Version/s: Undefined future
• Component/s: Core Library
• Assignee: Andrus Adamchik
• Reporter: Andrus Adamchik
• Created: 24/Dec/09 12:30
• Updated: 06/Jan/10 10:03

Description

This is something that came up in my work, and the feature is about allowing Cayenne to handle some really loose schemas. Consider 2 tables:

t1 ( pk1, pk2, c1)
t2 ( pk, fk_c1, fk_pk2)

t1 has PK defined as (pk1,pk2), at the same time (pk2, c1) also uniquely identifies each row. A relationship t2 join t1 on (t2.fk_c1 = t1.c1 and t2.fk_pk2 = t1.pk2) doesn't work. When 1..N part is resolved, a query like this is generated:

SELECT t2.* FROM t2 WHERE t2.fk_c1 = NULL AND t2.fk_pk2 = ? [bind: 1->fk_pk2:'correct_value']

This is not super high priority, but I think we should support such fuzzy relationships. Cayenne traditionally had strong support for various legacy schemas. So we should support this case as well.