SqlCommandBuilder not updating record in database

Question

private void btn_update_Click(object sender, EventArgs e){

try

{

conStr = @"--------------";

con = new SqlConnection(conStr);

con.Open();

string query = "Select * from tblProduct";

cmd = new SqlCommand(query, con);

sda = new SqlDataAdapter(cmd);

SqlCommandBuilder scb = new SqlCommandBuilder(sda);

sda.Update(tbl);

tbl.AcceptChanges();

con.Close();

MessageBox.Show("Data Updated :) ");

}

catch (Exception ex)

{

MessageBox.Show("error" + ex.Message);

}

}