Skip site navigation (1) Skip section navigation (2)

typlen field in the pg_type table

From: Paul Tilles <Paul(dot)Tilles(at)noaa(dot)gov>
To: interfaces <pgsql-interfaces(at)postgresql(dot)org>
Subject: typlen field in the pg_type table
Date: 2004-07-08 18:29:41
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-interfaces
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

Paul Tilles

pgsql-interfaces by date

Next:From: Paul TillesDate: 2004-07-08 18:39:49
Subject: [Fwd: typlen field in the pg_type table]
Previous:From: L J BayukDate: 2004-07-08 01:12:44
Subject: Re: pgin.tcl pg_exec_prepared slow (was: Released...)

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group