实体框架和SQL Server的保存点 [英] Entity Framework and SQL Server Savepoints

问题描述

我问了一个不同的问题有关嵌套事务，并回答我的问题，教育了我足够的帮我意识到我是问这个问题不好。所以这里有一个更好的问题。

I asked a different question about Nested Transactions and the answer to my question educated me enough to help me realize I was asking the question poorly. So here's a better question.

我如何能够有效地执行SQ​​L Server的保存点（的链接1 ，链接2 ）与在实体框架建立了一个DAL 4.0？

How can I effectively implement SQL Server Savepoints (link 1, link 2) with a DAL built upon Entity Framework 4.0?

我想写出下面code和有它的工作方式是SQL Server的保存点

I would LIKE to write the following code and have it work in a way that SQL Server's SAVEPOINTS

public void Bar()
{
  using (var ts = new TransactionScope())
  {
    var ctx = new Context();
    DoSomeStuff(ctx);

    bool isSuccessful;

    using (var spA = new SavePoint("A")) // <-- this object doesn't really exist, I don't think
    {
      isSuccessful = DoSomeOtherStuff(ctx);
      if (isSuccessful)
        spA.Complete(); // else rollback bo prior to the beginning of this using block
    }

    Log(ctx, isSuccessful);

    ts.Complete();
  }
}

有没有这样的方式做任何事情，甚至接近类似这种，或者说起到很好地与EF4别的东西吗？ （我们使用自定义的自我跟踪POCO实体）

Is there such a way to do anything even close to resembling this, or something else that plays nicely with EF4? (we use custom self-tracking POCO entities)

推荐答案

这是不是一个相当完整的答案，但我怀疑这样的事情可能会下降正确的道路。我的问题是，<一个href="http://stackoverflow.com/questions/6989782/possible-to-get-sqltransaction-from-ambient-transaction">I'm不完全知道如何获得的SqlTransaction而在一个TransactionScope 。

This isn't quite a full answer, but I suspect something like this might be going down the right path. My problem is that I'm not entirely sure how to get a SqlTransaction while in a TransactionScope.

/// <summary>
/// Makes a code block transactional in a way that can be partially rolled-back. This class cannot be inherited.
/// </summary>
/// <remarks>
/// This class makes use of SQL Server's SAVEPOINT feature, and requires an existing transaction.
/// If using TransactionScope, utilize the DependentTransaction class to obtain the current Transaction that this class requires.
/// </remarks>
public sealed class TransactionSavePoint : IDisposable
{
    public bool IsComplete { get; protected set; }
    internal SqlTransaction Transaction { get; set; }
    internal string SavePointName { get; set; }

    private readonly List<ConnectionState> _validConnectionStates = new List<ConnectionState>
                                                                        {
                                                                            ConnectionState.Open
                                                                        };

    public TransactionSavePoint(SqlTransaction transaction, string savePointName)
    {
        IsComplete = false;
        Transaction = transaction;
        SavePointName = savePointName;

        if (!_validConnectionStates.Contains(Transaction.Connection.State))
        {
            throw new ApplicationException("Invalid connection state: " + Transaction.Connection.State);
        }

        Transaction.Save(SavePointName);
    }

    /// <summary>
    /// Indicates that all operations within the savepoint are completed successfully.
    /// </summary>
    public void Complete()
    {
        IsComplete = true;
    }

    /// <summary>
    /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
    /// </summary>
    public void Dispose()
    {
        if (!IsComplete)
        {
            Transaction.Rollback(SavePointName);
        }
    }
}

这会被消耗掉如此，非常类似于一个TransactionScope：

This would be consumed as such, very similarly to a TransactionScope:

SqlTransaction myTransaction = Foo();

using (var tsp = new TransactionSavePoint(myTransaction , "SavePointName"))
{
  try
  {
    DoStuff();
    tsp.Complete
  }
  catch (Exception err)
  {
    LogError(err);
  }
}

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