Re: String manipulation

Bruce Momjian <pgman@candle.pha.pa.us> writes:
> I don't think it is good practice for a CHECK constraint to change its
> behavior based on a GUC variable.

You can develop comparable "failure scenarios" for any of the GUC
variables that affect query semantics --- timezone, sql_inheritance,
you name it.  Locking them all down when a check constraint or function
or view is created seems impractical ... and if we did do it then we'd
get complaints about that too.  ("What do you mean I can't change the
setting later?")

In practice I think we have to assume that those variables are set
consistently within any one application.  If you go frobbing them
on-the-fly then you're going to have issues.

I suppose paranoid sorts might lobby to make any GUC variable that can
change query semantics be a superuser-only setting, but to me that cure
sounds worse than the disease.

            regards, tom lane