SQL的事务处理

SqlTransaction st;
   SqlConnection con;
   SqlCommand cmdUpdateA;
   SqlCommand cmdUpdateB;
   con=new SqlConnection("Server=.;database=gggcorn;uid=sa;pwd=");
   cmdUpdateA=new SqlCommand("update data set Datas='"+this.TextBox3.Text+"'where ID=1 ",con);
   cmdUpdateB=new SqlCommand("update data set Datas='"+this.TextBox3.Text+"'where ID=2 ",con);
   con.Open();
   st=con.BeginTransaction();
   cmdUpdateA.Transaction=st;
   cmdUpdateB.Transaction=st;
   try
   {
    cmdUpdateA.ExecuteNonQuery();
    cmdUpdateB.ExecuteNonQuery();
    st.Commit();
    this.Response.Write("<script>alert('success');</script>");
   }
   catch(Exception ex)
   {
    st.Rollback();
    this.Response.Write("<script>alert('fail');</script>");
   }
   finally
   {
    con.Close();
   }