Re: Why no 1to1 relationships?
Re: Why no 1to1 relationships?
- Subject: Re: Why no 1to1 relationships?
- From: Andrew Lindesay <email@hidden>
- Date: Wed, 2 Apr 2008 16:41:17 +1300
Hello Jeff;
I've decided to fully EOize my app to replace my current use of flat
files, mainly to better deal with concurrency issues. In creating
my analogous tables, I found that there's no way to specify a "1 to
1" relationship between tables using the Entity Modeler tool. Is
there a specific reason for this? Or is it just figured that you
might as well make it one to many anyway even if it is just one to
one?
"You can't really do that" :) However if you make a 1:M relationship
you can add an accessor-method which just makes the :M a :1 or throws
a runtime exception if it find a :M with more than one element in it.
On the very rare occasions where a 1:1 has made any sense, I have done
this.
If you're wondering why I want to do this, it's to hopefully reduce
conflicts of multiple people updating the same record in a table.
Is that generally a good reason to split 1 to 1 data into two tables?
Are you looking to prevent optimistic-locking-on-write conflicts?
Perhaps it would be better to implement a change-notification system
to keep the data fresh in the instances?
cheers.
___
Andrew Lindesay
www.lindesay.co.nz
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