Working of a DataAdapter:

        protected void Page_Load(object sender, EventArgs e)

        {

            //Windows Authentication

            String ConnectionString = "server=localhost; database=AdventureWorks; Integrated Security=True";

            SqlConnection conn = new SqlConnection(ConnectionString);

            conn.Open();

            string qryString = "SELECT TOP 10 * FROM Person.Contact";

            SqlDataAdapter da = new SqlDataAdapter(qryString, conn);

            DataSet ds = new DataSet();

            da.Fill(ds, "Employee");

        }

DataSet Component:

A DataSet is the component responsible for disconnected data architecture.  Every DataTable of a DataSet contains Columns collection of DataColumn object and the Rows collection of DataRow objects.

The DataRow contains actual field values and these field values can be accessed field name, like inmyRow[“FiledName”].

The data in the data source is never touched at all when you are working with the DataSet objects. Instead, all the changes are done locally to the DataSet in memory. Then the changes which are made into the DataSet will be updated in the actual database.