回滚在C#中不起作用

我正在使用C#和MYSQL，回滚不起作用。我有三个delete语句，其中表第三个delete SQL不存在，在catch中我正在进行回滚，但它只发生在时的第三个

         string id = dataGridView1.Rows[index].Cells[0].Value.ToString();
         string strDelete = "DELETE FROM user WHERE id = " + id;
         OdbcTransaction transaction = null;
         OdbcCommand cmd = new OdbcCommand();
         cmd.Connection = Singleton.Instance.GetConnection();
         transaction = Singleton.Instance.GetConnection().BeginTransaction();
         cmd.Transaction = transaction;
         try
         {
             cmd.CommandText = strDelete;
             cmd.ExecuteNonQuery();
             // delete from userdata
             strDelete = "DELETE FROM userdata WHERE id = " + id;
             cmd.CommandText = strDelete;
             cmd.ExecuteNonQuery();
             // delete from usersystem
             strDelete = "DELETE FROM usersystem WHERE id = " + id;
             cmd.CommandText = strDelete;
             cmd.ExecuteNonQuery();
             // delete from user systemstatus. here table don't exists, will throw 
             // exception 
             strDelete = "DELETE FROM usersystemstatusAAAA WHERE id = " + id;
             cmd.CommandText = strDelete;
             cmd.ExecuteNonQuery();
             transaction.Commit();
         }
         catch (Exception ex)
         {
             // Attempt to roll back the transaction.
             try
             {
                 transaction.Rollback();
             }
             catch (Exception ex2)
             {
                 Console.WriteLine("  Message: {0}", ex2.Message);
             }
         }

在这里，前两个SQL语句被提交，同时假定回滚所有语句。