[CAY-1710] Change default delete rule for runtime relationship

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: Core Library
• Assignee: Unassigned
• Reporter: Pavel Dyadych
• Created: 05/Jun/12 16:22
• Updated: 09/Jun/12 11:56

Description

It should be good to change default delete rule of runtime relationship from NO_ACTION to NULLIFY. It will protect us from bogus references in dependent objects without reverse relationships.

Suppose we have such model:

• ARTIST(ID, NAME) ==> Artist(name, paintings)
• PAINTING(ID, NAME, ARTIST_ID, GALLERY_ID) ==> Painting(name, artist) // no reverse to Gallery
• GALLERY(ID, NAME) ==> Gallery(name, paintings)

Delete rule of relationship Artist-toMany-Paintings is set to CASCADE. Expect that after deleting Artist corresponding Paintings will be deleted too.. and also deleted from galleries thanks to reverse runtime relationship Painting-toOne-Gallery created by Cayenne.

After adding data to database (print result of SelectQuery):

• Artists: Picasso
• Paintings: "Girl Reading at a Table" by Picasso
• Galleries: Metropolitan Museum of Art: ["Girl Reading at a Table" by Picasso]

After deleting object Picasso (print result of SelectQuery):

• Artists:
• Paintings:
• Galleries: Metropolitan Museum of Art: ["Girl Reading at a Table" by null] // that is BIZARRE!

This happens because when cascade delete comes to painting Girl it detects relationship with delete rule NO_ACTION. And so gallery stays with bogus reference.

PS. After recreation of ObjectContext all bogus objects of course dissapear because they do not exist in database.