Re: Subclassing and Reusable Components
Re: Subclassing and Reusable Components
- Subject: Re: Subclassing and Reusable Components
- From: Chuck Hill <email@hidden>
- Date: Mon, 25 Oct 2004 21:59:34 -0700
At 12:53 AM 26/10/2004 -0400, Jaime Magiera wrote:
>On Oct 26, 2004, at 12:29 AM, Chuck Hill wrote:
>> Ah, right. Subclassing is an OO concept that does not translate well
>> into a relational database.
>
>I didn't want to go any further until I really understood what's going
>on.
>
Some of the Apple docs on this area are quite good. May I suggest starting
with them if you have not read them already.
>> If you use something other than single table
>> inheritance you will not be able to apply FK constraints at the
>> database level. I just leave them off and trust in EOF.
>
>Ah, right. It's in the EO Manual, but for some reason didn't sink in.
>Now it's clear. Thanks.
>
>> I'd have one component that displays the common stuff, and one for each
>> subclass for the unique stuff. Both would get used to display
>> different
>> parts of the same EO. You can use the Entity name of the object to
>> map to
>> the relevant editor component and get WOSwitchcomponent to show the
>> correct one. In the subclass specifc editor subcomponent just cast
>> the EO to what it really it.
>
>Ok, that makes sense since JavaClient uses entityName and
>Switchcomponents now that I think about it (note to self: start
>drinking coffee).
>
And its Monday too! :-)
Thanks again Chuck, one of these days I'm going to
>have to buy you a coffee. You've been amazingly helpful.
>
Always a pleasure.
Chuck
--
Chuck Hill email@hidden
Global Village Consulting Inc. http://www.global-village.net
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