Hi, On Apr 3, 2009, at 10:12 AM, Sushrut Sathe wrote: > Hi, > In my table there is no id field,i.e. I have the field with the name > id_host > then how to use that field in my application without changing the > field > name. Assuming you mean Rails, you may have better luck next time asking on their list. Try this: class ModelName < ActiveRecord::Base set_primary_key "id_host" end - Stephen