Re: Inverse to-one relationships
Re: Inverse to-one relationships
- Subject: Re: Inverse to-one relationships
- From: Chuck Hill <email@hidden>
- Date: Thu, 22 Jul 2010 15:56:27 -0700
On Jul 22, 2010, at 3:39 PM, Paul Hoadley wrote:
> On 23/07/2010, at 7:42 AM, Chuck Hill wrote:
>
>>>> How are you modeling these relationships?
>>>
>>> Originally, just this: a mandatory, to-one relationship from A to B. Consider it to be a parent (B) with optional child (A). Every child has a parent (hence the current mandatory to-one from A to B), and every parent has zero or one child. So I've tacked on an optional to-one relationship from B to A to model the latter. I take it there's no way to convince EOF that these relationships are inverses, and get the convenience of updating both sides of the relationship at the same time.
>>
>> Where are the FKs? B hold's A's PK as an FK?
>
> Yes, and vice versa. Only difference is that B to A is optional (parent can have zero children), A to B is mandatory (child must have a parent).
>
>> They both have the same PK?
>
> No. (Would this help?)
It would make it worse, I just wanted to understand the situation.
--
Chuck Hill Senior Consultant / VP Development
Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems.
http://www.global-village.net/products/practical_webobjects
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