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Re: Setting up horizontal inheritance
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Re: Setting up horizontal inheritance


  • Subject: Re: Setting up horizontal inheritance
  • From: Paul Hoadley <email@hidden>
  • Date: Sun, 2 Nov 2008 13:21:38 +1030

On 02/11/2008, at 10:55 AM, Chuck Hill wrote:

Maybe I should take a step back. I assumed I wanted inheritance at all because I have a basic EO called Person in a model in a utility framework, and in a particular app I want to add three relationships to app-specific EOs. (In other apps, Person might be sufficient as it is, and I would instantiate it as an EO.) Is this an example of where one would use inheritance? Is HI a bad choice, and should I use STI instead?

I'd probably use HI in this case. I might also just dynamically add the relationships when the models are loaded.

I didn't even know that was possible.

HI is less tricky.

I've implemented it using HI, and it seems to be working. I'm not convinced I have it quite right, though. There's another EO in the utility-framework's model, UserPreference. UserPreference has a to- one relationship with Person to denote the owner of the preference. In the particular app, though, I'm now using AMPersons, and hence the amperson table in the database---but UserPreference.person relationship obviously looks for a Person in the 'person' table, and there aren't any. To overcome this, I have sub-classed UserPreference to create AMUserPreference, with the only change being that the person relationship points to AMPerson. This seems inelegant to me---am I doing it right? (Or is this a candidate for the kind of dynamic model change you refer to above?)



-- Paul.

w  http://logicsquad.net/
h  http://paul.hoadley.name/


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 >Re: Setting up horizontal inheritance (From: Chuck Hill <email@hidden>)

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