Re: Conditional INSERT: if not exists

One way would be to create a Primary Index containing all columns in the
table...?

For example - a table called "grps" with 3 colums:
CREATE TABLE grps
(
code varchar(4) NOT NULL,
description text NOT NULL,
category varchar(3),
CONSTRAINT groups_pkey PRIMARY KEY (code,description,category)
)

An insert on this table will fail if the values for each column in the row
you are attempting to insert already matches and existing row - Example:

code | description | category
------+----------------------------------------+----------
0001 | GROUP NOT DEFINED | OT1
0009 | NEWLY CREATED PRODUCTS | OT1
0010 | GROUP NOT SET | OT1

Then attempting:
INSERT INTO grps VALUES ('0001', 'GROUP NOT DEFINED', 'OT1');
This will fail as it already matches the first row in the table.

This WILL work (with a different value in the third column):
INSERT INTO grps VALUES ('0001', 'GROUP NOT DEFINED', 'OT2');

Cheers,
-p

-----Original Message-----
From: pgsql-novice-owner(at)postgresql(dot)org
[mailto:pgsql-novice-owner(at)postgresql(dot)org] On Behalf Of Don Morrison
Sent: Tuesday, 22 August 2006 10:43
To: pgsql-novice(at)postgresql(dot)org
Subject: [NOVICE] Conditional INSERT: if not exists

I want to insert a row unless it exists already. Do I have to write a
stored procedure to do this?

Thanks,
Don

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