Explain DataAdapter Object

It populates dataset from data source. It contains a reference to the connection object and opens and closes the connection automatically when reading from or writing to the database.

Example:
SqlDataAdapter daEmp = new SqlDataAdapter( "select EmpID, EmpName, Salary from Employees", conn);

Fill Method
It is used to populate dataset.
example: daEmp.Fill(dsEmp,"Employee");

Update Method
It is used to update database.
example: daEmp.Update(dsEmp,"Employee");