I am trying to create a browser enabled infopath form that should
retrieve the database records, update the changes in existing
populated records and / or add new records to the database table.

To achieve this, I have created a webservice which has 2 methods,
first method returns a dataset (used to populate the form fields) and
the second method accepts the dataset( used to update the database
table in case of any change(s)).

If I try to retrieve records and modify / add new records using
infopath client (design form without browser compatibility),
everything works fine. However, if I design the browser compatible
form and try to modify or add new record(s), its not working.

Am I missing anything?