Re: [INTERFACES] Getting max. value size (libpq++)

On Thu, 1 Jul 1999, Peter T Mount wrote:
> >     Okay, maybe I'm just not finding it in the documentation, but is
> > there a way to find out the max size of a field?  Specifically VARCHAR
> > fields.  For instance if I have a table created with the SQL code:
> > 
> > CREATE TABLE temp_table
> > ( name VARCHAR(30),
> >   id VARCHAR(10),
> >   address VARCHAR(60));
> > 
> >     Now the program I'm writing will add whatever the user wants to
> > this table, of what ever size.  I'm trying to avoid locking the size of
> > the HTML input fields.  So is there anyway to get those numbers back from
> > Postgres?  Right now they're hard-coded in, which really sucks.  Thanks.
> You need to query the system tables to do this.
> Something like (I've not tested this, just lifting bits from the jdbc
> source):
> 
>     select a.attname,a.attlen from pg_attribute a,pg_class c
>     where c.relname like 'temp_table'
>         and a.attrelid=c.oid
>         and a.attnum>0
>     order by a.attnum;
Thanks for the idea, but it it isn't able to tell me what the max.
size of varchars are.  It returns -1 for them.  I think this must be the
method that the libpq++ (PgDatabase).FieldSize(int), as it returns those
same numbers.
I'm pretty sure there's a way to do what I want, as the command
pg_dumpall (from a shell), some how has the numbers that I want.
              -- Philippe Chaintreuil                  peep@thefront.com