C#哪位大神帮我看下，我哪里错了

代码如下：

//点击删除
    private void delete_btn_Click(object sender, EventArgs e)
    {
        if (productId == -1)
        {
            MessageBox.Show("请先选择产品");
            return;
        }
        MessageBox.Show(productId.toString());
        DBHelper.conn.Open();
        OleDbTransaction tran = DBHelper.conn.BeginTransaction();
        string deleteProduct = string.Format(@"update product set p_delete_flag = 1 where p_id = {0}", productId);
        OleDbCommand deleteProductCmd = new OleDbCommand(deleteProduct, DBHelper.conn);
        deleteProductCmd.Transaction = tran;
        string deleteRate = string.Format(@"update rate set r_delete_flag = 1 where r_p_id = {0}", productId);
        OleDbCommand deleteRateCmd = new OleDbCommand(deleteRate, DBHelper.conn);
        deleteRateCmd.Transaction = tran;
        try
        {
            int a = deleteProductCmd.ExecuteNonQuery();
            MessageBox.Show(a.ToString());
            int b = deleteRateCmd.ExecuteNonQuery();
            MessageBox.Show(b.ToString());
            MessageBox.Show("删除成功");
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
            tran.Rollback();
        }
        finally
        {
            deleteProductCmd.Dispose();
            deleteRateCmd.Dispose();
            DBHelper.conn.Close();
        }
    }

productId = 21

a= 1 数据库确实是一行
b=2 数据库里确实存在两行
返回数据库一看。。。一点没变

缺少事务的提交操作吧，只看到了事务开始BeginTransaction()和滚回Rollback()，怎么没有提交啊

这个要结合你的数据库的表定义、数据库连接、数据库中的数据以及你的查询条件输入去看，建议你通过调试程序去解决。

具体的错误内容是什么？