Question

I’m using TransactionScope to manage transactions in EF, i need a ReadCommited behavior but it doesn’t works as expected :

using (var trans = new TransactionScope(TransactionScopeOption.Required, 
                            new TransactionOptions() 
                                { IsolationLevel = IsolationLevel.ReadCommitted}))
{
    var c1 = customerRepository.Get(1);
    c1.FirstName = "Modified";
    customerRepository.Save();

    var c2 = customerRepository.Get(1);
    Assert.AreNotEqual("Modified", c2.FirstName);

    trans.Complete();
}

while i still didn’t committed the transaction when getting the second instance, it’s FirstName is already modified.

Answer 1

You’re inside the same transaction. The transaction isolation level refers to different transactions.

You can’t isolate a translation from itself, but of other different transactions.

Try opening two different transaction scopes (i.e. with two apps running at the same time) and you’ll see the effect os isolation between them. You can do this debugging two different apps at the same time, and pausing them before commiting the scope.

Look SET TRANSACTION ISOLATION LEVEL (Transact-SQL)

As you can see, when each transaction isolation level is explained, it always refers to other transactions:

READ UNCOMMITTED
Specifies that statements can read rows that have been modified by other transactions but not yet committed.

READ COMMITTED
Specifies that statements cannot read data that has been modified but not committed by other transactions.

REPEATABLE READ
Specifies that statements cannot read data that has been modified but not yet committed by other transactions and …

and so on.