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Re: Inverse to-one relationships
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Re: Inverse to-one relationships


  • Subject: Re: Inverse to-one relationships
  • From: Chuck Hill <email@hidden>
  • Date: Thu, 22 Jul 2010 15:12:38 -0700

On Jul 22, 2010, at 2:49 PM, Paul Hoadley wrote:

> On 23/07/2010, at 12:09 AM, Chuck Hill wrote:
>
>>> I know this topic comes up on the list from time to time, but I just need a quick sanity check.
>>
>> Nope, not sane.  :-)
>
> Well spotted.  Now on with this:
>
>>> I have two entities, A and B.  For every A, there is a corresponding B.  For some subset of all Bs, each has a corresponding A.  Currently I have modelled this with a single relationship from A to B, so that's a mandatory to-one relationship.  (Alternatively, I could have modelled it with an optional to-one relationship from B to A.)
>>
>> 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?   They both have the same PK?

Chuck

--
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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  • Follow-Ups:
    • Re: Inverse to-one relationships
      • From: Paul Hoadley <email@hidden>
References: 
 >Inverse to-one relationships (From: Paul Hoadley <email@hidden>)
 >Re: Inverse to-one relationships (From: Chuck Hill <email@hidden>)
 >Re: Inverse to-one relationships (From: Paul Hoadley <email@hidden>)

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