Thread: Constraint, Rule, or Trigger?
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 -- Randy Perry sysTame Mac Consulting/Sales
> 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
on 8/10/01 10:53 PM, Joe Conway at joseph.conway@home.com wrote: >> 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 > Thanks, it does. -- Randy Perry sysTame Mac Consulting/Sales