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Re: Inheritence issue scheme advice?

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On 2011-06-29 22:54, Casey Havenor wrote:
Problem:
  I like many other have come across the inherit issues.

I found the thread here about such issue...
http://postgresql.1045698.n5.nabble.com/FK-s-to-refer-to-rows-in-inheritance-child-td3287684.html

I grabbed the "fk_inheritance.v1.patch" file and have been trying to install
it for the last two hours. -- Got some help in hackers space so figured this
out.  BUT was it was recommended not to utilize a hacked version of
PostgreSQL.

For inheritance I'm using it for the following.  ONLY on/with UNIQUE
CONSTRAINTS and FOREIGN KEYS with OIDS enabled - which from my understanding
that shouldn't be an issues as there shouldn't any duplicate entries that
cause a deadlock?   -- So I would think this patch would be ok?
There are currently two caveats with the patch you mention

1: the user has to ensure global uniqueness of all pk's in an inheritance hierarchy. This is not a problem at all if e.g. your root relation has a pk with e.g. a default value from a sequence. The childs will inherit that default value from the same sequence.

2: the patch enables inserting rows in a relation that has a fk to a inheritance parent/root, with an fk key value that is found in one of the child relations of the refered relation. The patch as is fails to block deleting the referred record in the child relation: that check currently only works for referred records in actual relation the fk points to, not it's childs. It is not impossible to add this, but it just hasn't been programmed yet. So a trigger check to prevent these deletions also has to be made in user space.

I'd very much appreciate any feedback you have on the patch, if it matches your usecase.

regards,

--
Yeb Havinga
http://www.mgrid.net/
Mastering Medical Data


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