EF Code First DBContext and Transactions

Question

I would like know what is the best possible way to implement transactions with DBContext. In particular,

1. Does DbContext.SaveChanges implement transaction internall if i change multiple entities?
2. If i want to call DbContext.SaveChanges multiple times(same contxet/different contxets), how transaction can be achieved?

Solution

1. Yes. SaveChanges uses transaction internally.
2. Use TransactionScope to wrap multiple calls to SaveChanges

Example:

using(var scope = new TransactionScope(TransactionScopeOption.Required,
    new TransactionOptions { IsolationLevel = IsolationLevel.ReadCommitted }))
{
    // Do something 
    context.SaveChanges();
    // Do something else
    context.SaveChanges();

    scope.Complete();
}

Comments

[Lukazoid]

Be sure to be using Sql 2008 or later as the database (or have the MSDTC service running on the client). Previous versions will escalate the transaction to a distributed transaction on the second SaveChanges. This is due to how DbContext internally handles the opening and closing of its connection.

[JarrettV]

Is is possible to get an identity from the first save changes? I always see Id = 0.

[Sunny]

@JarrettV - I think your issue is because of the IsolationLevel settings. Lowering it might help...

[renegadeMind]

This wont work with EF 4.3.1. We will have to open the connection on the Objectcontext explicitly before we call context.SaveChanges().

[Ladislav Mrnka]

@renegadeMind: Of course this will work with DbContext. What you describe is advanced way used when you want to avoid distributed transaction.

[renegadeMind]

@LadislavMrnka Yes you are correct; but don't we want to avoid DTC by default? I assumed that we do and hence my answer!