Again, the issue is not our tool, but the deficiency in libpq/postgres ... even mysql gets its right .. why not Postgres?
Its not hard for a database to report metadata properly.
if I issue a sql statement:
select '123' from <any table>
the database should report that the maximum length of the 1st column in the resultset is 3 ... it cant be any more plain than that.
Thanks
lm
From: Hannu Krosing [mailto:hannu@skype.net]
Sent: Mon 6/11/2007 10:43 PM
To: Larry McGhaw
Cc: Tom Lane; Alvaro Herrera; Dann Corbit; Gregory Stark; Martijn van Oosterhout; pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] Selecting a constant question
Ühel kenal päeval, E, 2007-06-11 kell 22:11, kirjutas Larry McGhaw:
> As far as I am aware these statements are true. If you have a
> specific example you could provide to the contrary that would be
> interesting.
>
> Even if there are such conditions it does not change the fact that
> libpq and/or postgresql is deficient in this area.
>
> For any query, the database should be capable of describing the
> metadata for the columns, which includes
> 1) the column type
> and
> 2) the column maximum length.
>
> This is such a basic database interface principle that I very
> disappointed that someone has not recognized this and simply said "
> yes, we see the issue we will work on it".
>
> Again, *all* other major relational databases do this ... even blob
> fields have a maximum length reported from the database.
>
> I hope someone who truly understands database interfaces will read
> this thread and address the issue.
> For now we will have to "special case" postgres in our application
> until it is addressed.
>
or redesign your application so that it allocates memory as needed and
won't waste client memory by allocating maximum possible amount for each
and every grid cell weather needed or not ;)
As I understand from this discussion you are writing some kind of
middleware (i.e. tools), and I'd expect toolmakers to do the right
thing.
allocating as much as possibly ever needed is something that would be
excusable in quick-n-dirty end user application, but not in a tool.
----------------
Hannu
