Re: Selecting a constant question

Ühel kenal päeval, E, 2007-06-11 kell 13:38, kirjutas Dann Corbit:
> > -----Original Message-----
> > From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
> > Sent: Monday, June 11, 2007 1:32 PM
> > To: Dann Corbit
> > Cc: Gregory Stark; pgsql-hackers(at)postgresql(dot)org
> > Subject: Re: [HACKERS] Selecting a constant question
...
> > You should be treating typlen as signed not unsigned, and not assuming
> a
> > fixed width for any negative value.
> >
> > Since the width refers to the server internal representation, and not
> to
> > what comes down the wire, I find it pretty strange for an application
> to
> > be using typlen for anything at all actually.
>
> Thanks for the response.
>
> Since libpq function PQfsize returns -2 for all constant character
> strings in SQL statements ... What is the proper procedure to determine
> the length of a constant character column after query execution but
> before fetching the first row of data?

Why not just get the first row and determine the width from it before
you actually use any of tha data ?

----------
Hannu