Message-ID: <353F6BBC.50EB8C99@sid.trust.ee>
Date: Thu, 23 Apr 1998 19:26:36 +0300
From: Hannu Krosing <hannu@trust.ee>
MIME-Version: 1.0
To: Byron Nikolaidis <byronn@insightdist.com>
CC: PostgreSQL Hacker <pgsql-hackers@postgreSQL.org>,
	"pgsql-interfaces@postgreSQL.org" <pgsql-interfaces@postgreSQL.org>
Subject: Re: [INTERFACES] retrieving varchar size
References: <353F5423.85F6FBCB@insightdist.com>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Byron Nikolaidis wrote:
> 
> Hello,
> 
> I was wondering if it would be possible, in the Postgres backend, to
> send back the defined column size for the varchar data type (and
> possibly the char() type, i.e., bpchar) on a query?  Currently, it just
> sends back -1 for the size, which makes it difficult in the frontend
> (i.e., odbc driver) to determine what the size of the column is.

While the right solution to this is of course getting the size from 
backend, there exists a workaround now (assuming that the query is not 
too expensive). While ASCII cursors always hide the varchar sizes, 
binary ones return the size in actual data (by zero-padding the 
returned data to max size), so one can determine the actual max 
sizes by opening the query in binary cursor and then examining 
enough records to get one non-null field for each varchar field.

Hannu