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: Gavin Eadie <email@hidden>
- Date: Sun, 15 Jun 2008 01:32:15 -0400
Lucky I love learning! Things I learned:
... in WebObjects, if it's difficult, you're doing it wrongly!
... Chuck is always right (even if he doesn't mention flattening in
his book).
... Apple's documentation for EOF at WO version 4.5 rocks!
... Start with the model and let the database take care of itself.
WebObjects standard flattened many-to-many relationship was what I was
missing. I was focused on the legacy tables I was working with and
they were muddying the waters. My new code is now working perfectly,
is smaller than before, easier to read and I'm happy again. Thanks to
those who helped, thanks to those who didn't wonder out loud how I
ever got this far without comprehending some of the simpler aspects of
EOF ... Gav
On Jun 14, 2008, at 7:08 PM, Chuck Hill wrote:
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
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