am Tue, dem 22.08.2006, um 8:39:00 +0800 mailte gao iqiang folgendes: > Hello, > I met the following problem when i am using PostgreSQL as a backend > database: > I have a table "tabrel(a int primary key, b int)", and now there are for > example 100 records with column 'a' be from 1 to 100. When i'm going to add one Why do you want to do this? > to each 'a' and intended to get 'a' varing from 2 to 101, i use SQL query as > "update tabrel set a=a+1" , but i got " ERROR: duplicate key violates unique > constraint tabrel_a_key". You can do something like this: test=# create table foo (id int primary key); NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "foo_pkey" for table "foo" CREATE TABLE test=# insert into foo values(1); INSERT 0 1 test=# insert into foo values(2); INSERT 0 1 test=# insert into foo values(3); INSERT 0 1 test=# update foo set id = id+1; ERROR: duplicate key violates unique constraint "foo_pkey" test=# begin; BEGIN test=# update foo set id = id+100; UPDATE 3 test=# update foo set id = id-99; UPDATE 3 test=# commit; COMMIT test=# select * from foo; id ---- 2 3 4 (3 rows) Other solution: test=# begin; BEGIN test=# alter table foo drop constraint foo_pkey; ALTER TABLE test=# update foo set id = id+1; UPDATE 3 test=# alter table foo add primary key (id); NOTICE: ALTER TABLE / ADD PRIMARY KEY will create implicit index "foo_pkey" for table "foo" ALTER TABLE test=# commit; COMMIT HTH, Andreas -- Andreas Kretschmer Kontakt: Heynitz: 035242/47215, D1: 0160/7141639 (mehr: -> Header) GnuPG-ID: 0x3FFF606C, privat 0x7F4584DA http://wwwkeys.de.pgp.net
