Re: Constraint, Rule, or Trigger?

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От Joe Conway
Тема Re: Constraint, Rule, or Trigger?
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Msg-id 003701c12210$d7dc6190$0705a8c0@jecw2k1
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Ответ на Constraint, Rule, or Trigger?  (Randall Perry <rgp@systame.com>)
Ответы Re: Constraint, Rule, or Trigger?  (Randall Perry <rgp@systame.com>)
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> I've had experience with SQL and database design, but not much with rules
&
> triggers. What's the best method to accomplish the following it PGSQL:
>
> _Table A_ has a boolean field 'status'
>
> _Table B_ has a 1-1 child relationship to Table A.
>
> The rule, trigger, or contraint would have to enforce that: no record
could
> be created in B  if  the 'status' field was false in the parent record in
A
>
> Just point me in the right direction.
> Thanks
>

Well start here: http://www.postgresql.org/idocs/index.php?plpgsql.html
and in particular look at
http://www.postgresql.org/idocs/index.php?plpgsql-trigger.html

Also, if you have the source tree available, look at

<path-to-pgsql-source>\src\pl\plpgsql\test\triggers.sql

for lots of examples.

Hope this helps,

-- Joe



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