Hi there, I am having a problem with the following code: CREATE TABLE temp ( num integer UNIQUE ); INSERT INTO temp (num) VALUES (1); INSERT INTO temp (num) VALUES (2); INSERT INTO temp (num) VALUES (3); UPDATE temp SET num = num+1; If the update is really meant to be atomic then this should work, as the column is still unique afterwards. However, I get a ERROR: duplicate key violates unique constraint "temp_num_key" Is this something I misunderstand about SQL & ACID in general, a known problem in Posgresql, or bug which will be fixed sometime. Should I report this as a bug? Thanks for your help in advance! Ben Young ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://archives.postgresql.org