Question

private static void ExecuteSqlTransaction(string connectionString)
{
        while (AreUnprocessedRows())
        {
            DataTable dtItems = GetRowsToProcess(); //Gets 50 rows at a time

            using (SqlConnection connection = new SqlConnection(connectionString))
            {
                connection.Open();

                SqlCommand command = connection.CreateCommand();
                SqlTransaction transaction;

                // Start a local transaction.
                transaction = connection.BeginTransaction("SampleTransaction");

                // Must assign both transaction object and connection
                // to Command object for a pending local transaction
                command.Connection = connection;
                command.Transaction = transaction;

                try
                {
                    for(int i = 0; i < dtItems.Rows.Count; i++)
                    {
                        int intIndex = 0;
                        int.TryParse(Convert.ToString(dtItems.Rows[i][0]), out intIndex);
                        string strDesc = Convert.ToString(dtItems.Rows[i][1]).Trim();

                        command.CommandText = "Insert into Region (RegionID, RegionDescription) VALUES (" + intIndex + ", '" + strDesc + "')";
                        command.ExecuteNonQuery();

                        command.CommandText = "UPDATE ProcessedTable SET IsUpdated = 1 WHERE TheIndex = " + intIndex;
                        command.ExecuteNonQuery();
                    }

                    // Attempt to commit the transaction.
                    transaction.Commit();
                    //connection.Close(); //Original code has this
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Commit Exception Type: {0}", ex.GetType());
                    Console.WriteLine("  Message: {0}", ex.Message);

                    // Attempt to roll back the transaction.
                    try
                    {
                        transaction.Rollback();
                    }
                    catch (Exception ex2)
                    {
                        // This catch block will handle any errors that may have occurred
                        // on the server that would cause the rollback to fail, such as
                        // a closed connection.
                        Console.WriteLine("Rollback Exception Type: {0}", ex2.GetType());
                        Console.WriteLine("  Message: {0}", ex2.Message);
                    }
                }
            }
        }
    }

关于代码：

这是一种娱乐，因为实际代码非常大
while循环使它继续运行，同时仍有行标记为未处理
该代码将获得50行的批处理
原始代码在提交后已关闭连接

问题：

有时会发生数据库死锁，这种情况下，几行会插入到Region中，但不会在ProcessedTable中进行更新，因此会再次对其进行处理，从而导致Region表中出现重复
为什么Rollback不清理这些半完成的交易？
请注意，回滚块中没有异常的指示

我还可以通过数据库表索引看到死锁错误发生后立即重新处理和复制不完整的行

Answer 1

// Start a local transaction.
transaction = connection.BeginTransaction("SampleTransaction");

// Because of above line, you should rollback like following:
transaction.Rollback("SampleTransaction");

C＃事务不回滚

1 个答案: