Re: Best way to prevent overlapping dates

[Jeff Davis <pgsql(at)j-davis(dot)com>]

On Tue, 2007-05-29 at 10:59 -0500, Michael Glaesemann wrote:
> On May 25, 2007, at 3:22 , Andrus wrote:
> 
> > CREATE TRIGGER puhkus_sequenced_trigger BEFORE INSERT OR UPDATE ON  
> > puhkus
> >    FOR EACH ROW EXECUTE PROCEDURE puhkus_sequenced_pkey();
> 
> You can also use CREATE CONSTRAINT TRIGGER, which allows you to have  
> deferrable constraints. This is useful if statements within a  
> transaction may temporarily put the database in a state where it  
> violates the constraint: the constraint will be called at the end of  
> the transaction to make sure integrity is maintained.
> 
> http://www.postgresql.org/docs/8.2/interactive/sql-createconstraint.html
> 

The docs say:

"CREATE CONSTRAINT TRIGGER is used within CREATE TABLE/ALTER TABLE and
by pg_dump to create the special triggers for referential integrity. It
is not intended for general use."

Is there harm in using constraint triggers outside of pg_dump? It seems
like deferrable constraints would be useful for many applications, but
the docs imply that it's a bad idea.

Regards,
	Jeff Davis

PS: Nice to meet you at PGCon. Hope you enjoyed it as much as I did!