Message-ID: <40ED94F5.71337531@noaa.gov>
Date: Thu, 08 Jul 2004 14:39:49 -0400
From: Paul Tilles <Paul.Tilles@noaa.gov>
Organization: DOC/NOAA/NWS - National Weather Service
MIME-Version: 1.0
To: interfaces <pgsql-interfaces@postgresql.org>
Subject: [Fwd: typlen field in the pg_type table]
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Forgot to mention that I am working with Version 7.4.3.

Paul Tilles wrote:

> For each table in my database, I am trying to extract the column name,
> column type and column length from the system catalog tables.  I am able
> to get the column name from the pg_attribute table and the column type
> from the pg_type table.  However, I am having a problem extracting the
> length of character columns from the typlen field of the pg_type table.
>
> For example, I have a column defined as a char(20).  The column type is
> set to "bpchar" but the typlen value for this column is -1.  The
> documentation says that a value of -1 indicates "... has a length
> word".  Can I extract the length of the field (in this case 20) from any
> field in the system catalog tables?
>
> In the documentation (Section 43.29) for the typlen field, it says "...
> for a variable-length type, typlen is negative".  In Section 10.4, Item
> 3 says "... fixed-length type(e.g., char ...".  All of the char columns
> in my database have typlen = -1.  IS A CHAR FIELD CONSIDERED A
> FIXED-LENGTH OR VARIABLE-LENGTH TYPE BY POSTGRESQL?
>
> Paul Tilles