[
https://issues.apache.org/jira/browse/CAY-1710?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Pavel Dyadych updated CAY-1710:
-------------------------------
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.
was:
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 cascading 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.
> Change default delete rule for runtime relationship
> ---------------------------------------------------
>
> Key: CAY-1710
> URL: https://issues.apache.org/jira/browse/CAY-1710
> Project: Cayenne
> Issue Type: Improvement
> Components: Core Library
> Reporter: Pavel Dyadych
> Attachments: helloworld-mapping.zip
>
>
> 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.
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