Re: Query performance problem

Only specifying a default value does not prevent a NULL from being entered 
either through accident or ignorance:

jan28-05=# create table test (foo text, foo1 int4 default(0));
CREATE TABLE
jan28-05=# insert into test values('a',1);
INSERT 98685 1
jan28-05=# insert into test values('b',4);
INSERT 98686 1
jan28-05=# insert into test values('c',NULL);
INSERT 98687 1
jan28-05=# insert into test values('d');
INSERT 98688 1
jan28-05=# select * from test;foo | foo1
-----+------a   |    1b   |    4c   |d   |    0
(4 rows)

George

----- Original Message ----- 
From: "Kenneth Gonsalves" <lawgon@thenilgiris.com>
To: "Richard Huxton" <dev@archonet.com>
Cc: <weberp@paradise.net.nz>; <pgsql-sql@postgresql.org>
Sent: Thursday, March 17, 2005 11:19 PM
Subject: Re: [SQL] Query performance problem


On Thursday 17 Mar 2005 7:35 pm, Richard Huxton wrote:

> Not necessarily. NOT NULL here helps to ensure you can add values
> together without the risk of a null result. There are plenty of
> "amount" columns that should be not-null (total spent, total
> ordered etc).

that makes sense - but is it necessary to have a not null constraint
when there is a default value?

-- 
regards
kg

http://www.livejournal.com/users/lawgon
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