Re: compound primary key ("failed to provide new primary keys")
Re: compound primary key ("failed to provide new primary keys")
- Subject: Re: compound primary key ("failed to provide new primary keys")
- From: Chuck Hill <email@hidden>
- Date: Sat, 14 Jun 2008 16:08:46 -0700
On Jun 14, 2008, at 3:57 PM, Gavin Eadie wrote:
My reading would indicate that I don't want to "propagates primary
key". If I do, then the creation of an Advert WILL always create a
Select.
Nope. That is what Owns Destination does for a to-one, mandatory
relationship.
But Selects are not mandatory, in fact in this business model they
are scarce.
Why do they even have a class? If it is just two keys, just use an
EOGenericRecord and flatten the relationships. Then all you need to
do is to say user().addToFavoriteAdverts(ad); I don't think you
should even need the addObjectToBothSidesOfRelationshipWithKey. That
might cause too much faulting for popular ads.
The real world model is a bulletin board of advertisements whose
users may select some favorite ads that they want to keep track of.
So a boring ad will have no connecting Select, and someone who is
not a frequent visitor may have no connecting Select. On the other
hand a really interesting ad may have dozens of Selects (dozens of
people putting it in their favorites), and a busy user may have
dozens Selects (ads they are tracking). Any one Select contains
only the pkeys of the Advert and Author (user) it relates. This may
have been modeled badly seven years ago, but it's what I have to
work with !! Gav
Seems to me like it should be no trouble at all.
Chuck
On Jun 14, 2008, at 2:55 PM, Johann Werner wrote:
Hi Gavin,
did you check "Propagates Primary Key" on the Author and Advert
entity?
jw
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