实体框架和SQL Server保存点

Question

我问一个不同的问题有关嵌套事务和回答我的问题教育了我足够的帮助，我意识到我是问这个问题不好。 所以这是一个更好的问题。

如何使用基于Entity Framework 4.0构建的DAL有效地实现SQL Server保存点（ 链接1 ， 链接2 ）？

我希望编写以下代码，并使它以SQL Server SAVEPOINTS的方式工作

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();
  }
}

有没有办法做类似于此的事情，或者可以与EF4配合使用？ （我们使用自定义自跟踪POCO实体）

Answer 1

这不是一个完整的答案，但是我怀疑这样的事情可能会走上正确的道路。 我的问题是我不确定在TransactionScope中如何获取SqlTransaction 。

/// <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);
        }
    }
}

这样就可以使用它，非常类似于TransactionScope：

SqlTransaction myTransaction = Foo();

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