Re: Problem with triggers

2010/6/16 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>

> Adrian Klaver <adrian(dot)klaver(at)gmail(dot)com> writes:
> > On 06/15/2010 02:01 PM, Sid wrote:
> >> I am writing trigger function for validating values inserted into table.
> The
> >> goal is to print user friendly messages when inserted value is wrong.
>
> >> My question is: why do I get information about too long value before
> trigger
> >> fires?
>
> > The database is beating you to the validation.
>
> People try this every few months :-(, but it's basically a dead-end idea.

I tried to search for this problem, but I failed :(. I spend few hours
trying to find what is
wrong with my code.....

A large majority of the things you might want to report an error for are
> going to be rejected by the datatype input functions for the column
> datatypes --- for example, you're not going to be able to "print a user
> friendly message" on a bad timestamp, because that will be noticed long
> before any trigger gets to fire.
>
I didn't think about that,

>
> You can either decide that the built-in error messages aren't so awful
> after all, or do your data validation on the client side.
>
Yes, I'll probably do this that way.

> Or I guess you could lobotomize the database completely by making all
> your fields be unlimited-length varchar so that there's no interesting
> checking to be done. But you really, really don't want to go there.
>
No. This solution is too ugly even for me :)

>
> regards, tom lane
>

Thank you for your explanation, Tom

--
Best regards
Sid