Re: Why the ERROR: duplicate key violates unique constraint "master_pkey" is raised? - Is this a Bug?

Hi,

I am not using any sequences, The following batch can reproduce the
behaviour.

CREATE TABLE master ( m1 INT primary key , m2 int unique ) ;

INSERT INTO master VALUES ( 1, 1 ) ;

INSERT INTO master VALUES ( 2, 2) ;

UPDATE master SET m2 = m2 + 1;

With Cheers,

Anoo S

From: Ardian Xharra [mailto:axharra(at)boxxo(dot)info]
Sent: 25 September 2007 00:38
To: Anoo Sivadasan Pillai; pgsql-general(at)postgresql(dot)org
Cc: Anoo Sivadasan Pillai
Subject: Re: [GENERAL] Why the ERROR: duplicate key violates unique
constraint "master_pkey" is raised? - Is this a Bug?

Probably you are using a sequence, and if so you need to update the
value of sequence prior to update:

SELECT setval('master_m1_seq',((SELECT id_m1 FROM master ORDER BY 1 DESC
LIMIT 1)+1));

----- Original Message -----

From: Anoo Sivadasan Pillai <mailto:aspillai(at)in(dot)rm(dot)com>

To: pgsql-general(at)postgresql(dot)org

Cc: Anoo Sivadasan Pillai <mailto:aspillai(at)in(dot)rm(dot)com>

Sent: Monday, September 24, 2007 3:20 AM

Subject: [GENERAL] Why the ERROR: duplicate key violates unique
constraint "master_pkey" is raised? - Is this a Bug?

I am using "PostgreSQL 8.2.4 on i686-pc-mingw32, compiled by GCC
gcc.exe (GCC) 3.4.2 (mingw-special)" on Windows 2003 server

While I am trying to update a prmary key It is failing with the
following message "ERROR: duplicate key violates unique constraint
"master_pkey" "

Can anybody explain why this happens so? Sending the script
that I tried.

CREATE TABLE master ( m1 INT primary key , m2 VARCHAR(100)) ;

INSERT INTO master VALUES ( 1, 'm1' ) ;

INSERT INTO master VALUES ( 2, 'm2' ) ;

UPDATE master SET m1 = m1 + 1;

Update fails with the message - ERROR: duplicate key violates
unique constraint "master_pkey"

If I insert data in the reverse order it is making no problem.
Is this a Bug ?

I tried ,

TRUNCATE TABLE master;

INSERT INTO master VALUES ( 3, 'm3' ) ;

INSERT INTO master VALUES ( 2, 'm2' ) ;

UPDATE master SET m1 = m1 + 1;

It works perfectly.

Anoo S
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