[CAY-948] Implement flattened attributes in Cayenne

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0
• Fix Version/s: 3.0M3
• Component/s: Core Library
• Assignee: Andrus Adamchik
• Reporter: Andrus Adamchik
• Created: 22/Dec/07 21:53
• Updated: 09/Nov/08 00:59
• Resolved: 24/Dec/07 00:07

Description

We need to support flattened attributes in Cayenne.... JPA has a @SecondaryTable annotation, that is essentially a one step flattened attribute and IIRC Andriy implemented a similar mapping scenario long time ago (Cayenne 1.1), only without a Modeler support. So we need to finally make it official, create test cases, modeler support, etc.

In Cayenne API terms, flattened attribute is an object attribute mapped over a DbRelationship to a joined table column. A few things to consider:

• Whether to support multi-step flattened attributes
• Whether to load such attributes eagerly or lazily (JPA's default for @Basic is EAGER, but it is configurable...)