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@postgresql.org
[mailto:pgsql-novice-owner@postgresql.org] On Behalf Of Don Morrison
Sent: Tuesday, 22 August 2006 10:43
To: pgsql-novice@postgresql.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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