why my update method doesnot update database, rather it update my built-in dataset

Question

i m developing windows application
i have a problem i try my best to solve but i can't sove it.
i m using dataset for only fiewing data to the forms and i create my own class for updation and insertion but my updation query doesnot update database it update dataset..... how ever my connection string provide the path of the database rather then of dataset....
help me plz........
why my update method doesnot update database, rather it update my built-in dataset .

waiting for the reply.