Do you want to save changes in oracle forms

After I query the record and closing the form the error 'Do you want to save changes you have made' will appear without entering or modifying records in the form. So how can I avoid this message?

I defaulting some value for non-database item in Post Query trigger, which causes this message.

Finally used below code in Post Query trigger and worked. 

set_record_property(:system.trigger_record,:system.trigger_block,status,query_status);