C#批量写入SQL的问题

用的listView导入了所有数据库表数据
做了修改和添加
在listView插入SQL的时候出现主键重复问题，我想把重复的主键值做一个判断
判断主键值的信息是否被修改，有改动就更新数据
主键值没改动，就跳过继续执行下一条数据写入
具体要怎么写呀！！！
现在写入SQL的部分已经写好了，就是不知道判断如何写，重哪插入
        private void button8_Click(object sender, EventArgs e)
        {
            SqlConnection connection = null;
            try
            {
                connection = new SqlConnection(TBConnection.Text);
                connection.Open();

                SqlCommand command = new SqlCommand();
                command.Connection = connection;

                foreach (ListViewItem Item in listView1.Items)
                {
                    string simNo = Item.SubItems[0].Text;
                    int startHour = int.Parse(Item.SubItems[1].Text);
                    int startMinute = int.Parse(Item.SubItems[2].Text);
                    int endHour = int.Parse(Item.SubItems[3].Text);
                    int endMinute = int.Parse(Item.SubItems[4].Text);
                    int retSpan = int.Parse(Item.SubItems[5].Text);
                    int retSpanA = int.Parse(Item.SubItems[6].Text);
                    int retSpanB = int.Parse(Item.SubItems[7].Text);

                     = string.Format("INSERT  into Mobile(SimNo,StartHour,StartMinute,EndHour,EndMinute,RetSpan,RetSpan_A,RetSpan_B) values('{0}',{1},{2},{3},{4},{5},{6},{7})", simNo, startHour, startMinute, endHour, endMinute, retSpan,retSpanA,retSpanB);
                    command.ExecuteNonQuery();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                if (connection != null && connection.State == ConnectionState.Open)
                {
                    connection.Close();
                }
            }
        }