IS-A relationships in core data
IS-A relationships in core data
- Subject: IS-A relationships in core data
- From: Daniel Child <email@hidden>
- Date: Fri, 16 Nov 2007 01:23:06 -0500
Hi,
This is definitely a Core Data newbie question, but exactly how do
you handle IS-A relationships in Core Data.
I assume you designate the super entity as "Parent". But what about
attribute settings? Do you have the option to denormalize the data
(copy some attributes from the sub-entity into the super-entity)? (I
will eventually only be searching on one file, and only afterwards
getting related records from the other files.)
I'll give a concrete example.
Lets say I have a MasterList created from three separate lists,
ListA, ListB, and ListC. Let's say that the MasterList has certain
properties (last name, first name) in common that will also be found
in data from the individual lists. However, the structure of the
three individual lists may otherwise be different.
I will be getting the data for the individual lists from flat files
that I parse.
How do I set up the data model? I tried having identical names for
last name and first name, and got an error when I compiled. Then I
thought of having a MasterList recNum attribute, and then placing
that attribute in the individual lists (an approach recommended in
some database books), but that also caused a problem.
Since the basic tutorial describes HAS-A scenarios, I'm not getting
very far with the type of model I want to set up.
Thanks.
Daniel
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