How to update Data Table ?

    SqlConnection Conn=new SqlConnection("Server=Server_Name;Database=DB_Name;UID=Login_ID;PWD=Login_Pwd");
    SqlDataAdapter da=new SqlDataAdapter("SELECT uid, uname, fname, cont FROM Emp_Details WHERE uname LIKE 'Xyz%' ORDER BY uname", Conn);
    DataTable dt=new DataTable();
    DataRow dr;
    SqlCommandBuilder cb;

    da.Fill(dt);
    dr=dt.NewRow();
    dr["uid"]="9008";
    dr["uname"]="ABC";
    dr["fname"]="xyz";
    dr["cont"]=1;
    dt.Rows.Add(dr);

    cb=new SqlCommandBuilder(da);
    da.Update(dt);