however i also want that if the check box is unselected again then its value should not be stored in the database i.e. database should be updated again while unchecking the values..
Joined: Apr 10, 2010
It's quite the same.
If c1, as in the example above, is not checked, then the request parameter will be null instead of 1.
Starting from this distinction you will be able to update your database accordingly.