c# 数据库回滚

SqlConnection conn = new SqlConnection("Data Source = DATABASE-VPC\\SQL2005; User ID = sa; password = admin; Initial Catalog = Jiang; Pooling=true");
                SqlTransaction mytran;//引用
                conn.Open();
                mytran = conn.BeginTransaction();//形如数据事务
                try
                {
                    SqlCommand cmd = new SqlCommand();
      
                    cmd.Transaction = mytran;
                    cmd.Connection = conn;
                    cmd.CommandType = CommandType.Text;
                    cmd.CommandText = "insert into [member] values('admin')";
                    cmd.ExecuteNonQuery();
                    cmd.CommandType = CommandType.Text;
                    cmd.CommandText = "insert into [memberw] values('jiang')";
                    cmd.ExecuteNonQuery();
                    mytran.Commit();//提交数据库事务
                    conn.Close();
                }
                catch (Exception ex)
                {
                    mytran.Rollback();//回滚（出错的时候)
                }