Re: Delete rules on flattened relationships
Re: Delete rules on flattened relationships
- Subject: Re: Delete rules on flattened relationships
- From: Paul Hoadley <email@hidden>
- Date: Thu, 17 Nov 2011 16:10:29 +1030
On 17/11/2011, at 2:54 PM, David Avendasora wrote:
> On Nov 17, 2011, at 7:48 AM, Paul Hoadley wrote:
>
>> On 17/11/2011, at 10:08 AM, David Avendasora wrote:
>>
>>> On Nov 10, 2011, at 5:34 AM, Paul Hoadley wrote:
>>>
>>>> Say I have two entities, User and Role, and a joining entity UserRole to create a many-to-many relationship between them. So I have a relationship 'userRoles' from User to UserRole (and a relationship 'userRoles' from Role back to UserRole). I flatten the relationship on User, so I also have a 'roles' relationship on that entity.
>>>
>>> Wait. "Also"?!? That's insane. That's two distinct relationships representing the same DB information, and one is hiding a huge piece of the action. You are just asking for trouble.
>>
>> User.userRoles is not a class property. All that's exposed is the flattened User.roles.
>
> Okay, then that should be alright then, and I think nullify is the proper setting for the non-class "real" relationships.
(I think I've now officially confused everyone, and kind of regret starting this thread...) No, you want Cascade on the non-class "real" relationships (to remove the row in the join table), and Nullify on the flattened relationship—as Chuck noted, to remove the destination object from the flattened relationship.
>> I don't _think_ I'm talking about anything particularly unusual here, just the standard result of creating a many-to-many relationship with Entity Modeler, with a join entity and "Flatten relationships" checked.
>
> Not unusual, just something that you really shouldn't even be thinking about.
Point taken, though someone has to think about it at some point. I thought the default delete rule (Nullify) was wrong. Turns out I was incorrect. :-)
--
Paul.
http://logicsquad.net/
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