I want to update the leftdays ..row by row .. Not all at once .

<pre lang="c#">private void button3_Click(object sender, EventArgs e)
        {

            myconnection.Open();
            displayData();
            string selectSql = "select * from employTable2";
            SqlCommand com = new SqlCommand(selectSql, myconnection);
           using (SqlDataReader read = com.ExecuteReader())
            {
                while (read.Read())
                {
                    string first1 = read["salarydate"].ToString();
                    string Second1 = read["expiredate"].ToString();
                     TimeSpan t1 = Convert.ToDateTime(Second1) - DateTime.Now;
                    int daysleft = t1.Days;
                    SqlConnection myconnection1 = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=c:\documents and settings\muhammad\my documents\visual studio 2010\Projects\ProjectClock\ProjectClock\ClockDB.mdf;Integrated Security=True;User Instance=True;");
                    myconnection1.Open();
                    SqlCommand cmd1 = new SqlCommand("UPDATE employTable2 SET daysleft='" + daysleft.ToString() + "'", myconnection1);
                   
                    cmd1.ExecuteNonQuery();
                    myconnection1.Close();
                  MessageBox.Show(t1.Days +"", "Days Left");
                }
                myconnection.Close();

            } 
        }