On mán, 2006-04-10 at 22:43 -0700, v.suryaprabha@xxxxxxxxx wrote: > Hi > Now we cannot change the field type. Because already our application > is running and thousands of records are already entered. we are getting > same no for clipid when 2 users are entering data at a time. so how to > solve the problem create a sequence: CREATE SEQUENCE clipid_seq START WITH somehighenoughnumber now use that when you allocate ids. i.e. instead of SELECT 1+max(clipid) FROM yourtable do: SELECT nexval(clipid_seq) gnari