NHibernate: Multiple Transactions on a single session

Question

I want to know if there is any issue by creating several transactions on a single session, like this:

using (var session = factory.OpenSession())
{
    using (var trans1 = session.BeginTransaction())
    {
        .....
        trans1.commit();
    }

    using (var trans2 = session.BeginTransaction())
    {
        .....
        trans2.commit();
    }

    using (var trans3 = session.BeginTransaction())
    {
        .....
        trans3.commit();
    }

    using (var trans = session.BeginTransaction())
    {
        .....
        // trans1.commit();
    }
}

is that possible or must I open a new session object per transaction?

Thanks for your help.

Answer 1

Yes what you are doing is just fine.

What nhibernate does not support are multiple nested transactions.

Answer 2

It is not usual to have multiple transactions on a single session even in NHibernate. Also from personal experience I can say it is not a good idea to reuse sessions in any other situation.

I recommend to keep the workflow as simple as possible to avoid any side-effects:

• open session
• open transaction
• use your entities
• commit transaction
• rollback in case of exception
• close/flush session (always)

Answer 3

The most common strategy in a web environment is to have session per request.
When it cones to transactions, it really depends on your use-case.
What you are doing is fine, or otherwise nhibernate wouldn't separate session from transaction.
but yet again, it depends on your business case situation.

I suggest you to wrap the session.BeginTransaction() with IDisposable , so on Dispose you make sure to commit transaction .

Answer 4

No issues although it's unusual. Bear in mind that the session should be discarded if any of the transactions rolls back.