How can I have 2 ADO access methods use the same Transaction?

Question

I'm writing a test to see if my LINQ to Entity statement works.. I'll be using this for others if I can get this concept going..

my intention here is to INSERT a record with ADO, then verify it can be queried with LINQ, and then ROLLBACK the whole thing at the end.

I'm using ADO to insert because I don't want to use the object or the entity model that I am testing. I figure that a plain ADO INSERT should do fine.

problem is.. they both use different types of connections.

is it possible to have these 2 different data access methods use the same TRANSACTION so I can roll it back??

_conn = new SqlConnection(_connectionString);
_conn.Open();

_trans = _conn.BeginTransaction();

var x = new SqlCommand("INSERT INTO Table1(ID, LastName, FirstName, DateOfBirth) values('127', 'test2', 'user', '2-12-1939');", _conn);

x.ExecuteNonQuery();     //So far, so good.  Adding a record to the table.

//at this point, we need to do **_trans.Commit()** here because our Entity code can't use the same connection. Then I have to manually delete in the TestHarness.TearDown..  I'd like to eliminate this step


//(this code is in another object, I'll include it for brevity. Imagine that I passed the connection in)
//check to see if it is there
using (var ctx = new XEntities(_conn)) //can't do this.. _conn is not an EntityConnection! 
{
    var retVal = (from m in ctx.Table1
                  where m.first_name == "test2"
                  where m.last_name == "user"
                  where m.Date_of_Birth == "2-12-1939"
                  where m.ID == 127
                  select m).FirstOrDefault();

     return (retVal != null);
 }

//Do test.. Assert.BlahBlah();

_trans.Rollback();

Answer 1

Hmm...

http://msdn.microsoft.com/en-us/library/system.data.objects.objectcontext.executestorecommand(v=VS.100).aspx

_conn = new EntityConnection(_connectionString);
EntityTransaction myTrans = _conn.BeginTransaction();

using(MyObjectContext x = new MyObjectContext(_conn))
{
  x.ExecuteStoreCommand(insertString);
}

CallTest(_conn)

myTrans.Rollback();

Of course, since you have an object context at that point, you don't have to use ExecuteStoreCommand if you'd instead prefer to new up a data instance, attach and save changes.

Answer 2

Yes, just use TransactionScope:

using (TransactionScope ts = new TransactionScope()) {
    // Do something in ADO.NET with one connection.

    // Do something with Linq in another connection

    // Commit (or not if you want to roll back)
    //ts.Complete();
}

No other explicit transaction handling is needed. Note though that if you use two different connections, you will need to have DTC running.

Answer 3

Here was my final test that I created based upon my selected answer. I'm actually testing a service that makes a LINQ to Entities call to the database. (that LINQ you saw is basically what is in the WCF Service function)

This way I can call the service using the same connection I INSERTed with.. ( I could actually move the connection and transaction stuff to setup & teardown, but this is it in a nutshell)

   [Test]
    public void Test_VerifyXXX()
    {
        var _conn = new EntityConnection(_connectionString2);

        _conn.Open();
        EntityTransaction myTrans = _conn.BeginTransaction();

        using (var x = new XEntities(_conn))
        {
            x.ExecuteStoreCommand("INSERT INTO Table1(ID, LastName, FirstName, DateOfBirth) values('127', 'test2', 'user', '2-12-1939');");
        }             

        XService test = new XService_Mock(_conn);
        bool results = test.CustomerVerified(127, "user", "test2", new DateTime(1939, 2, 12));

        Assert.IsInstanceOf(typeof(bool), results);
        Assert.AreEqual(true, results);

        myTrans.Rollback();
    }