Question

I’m trying to use a session-per-request pattern and I’m having trouble with getting a record right after it’s been saved. The reason for doing that being that I need to get the records that the foreign keys relate to.

Some (simplified) code:

    // UnitOfWork Attribute

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        SessionFactory.Begin();
    }

    public override void OnResultExecuted(ResultExecutedContext filterContext)
    {
        if (filterContext.Exception == null) {
            try {
                SessionFactory.Commit();
            } catch {
                SessionFactory.Rollback();
                throw;
            }
        } else {
            SessionFactory.Rollback();
            throw filterContext.Exception;
        }
    }

    // Service layer

    public void Save(Form form)
    {
        _repository.Save(form);

        var savedForm = _repository.Get(form.Id);
        SendEmail(savedForm);
    }

    // Repository

    public void Save(Form form)
    {
        var session = SessionFactory.CurrentSession;

        session.SaveOrUpdate(form);
    }

The problem is that when I try to get the record, the transaction hasn’t yet been committed, so it just gives me what’s already in the session. Am I just going to have to commit the transaction after saving, and open a new transaction for getting it?

Thanks

Update:

I’ve implemented the Agathas Storefront way of doing things, giving the service layer control over the transactions, i.e.:

public class UnitOfWork : IUnitOfWork
{
    public void Commit()
    {
        var session = SessionFactory.CurrentSession;

        using (ITransaction transaction = session.BeginTransaction())
        {
            try { 
                transaction.Commit(); 
            } catch {
                transaction.Rollback();
                throw;
            }
        }
    }


    public void Clear()
    {
        var session = SessionFactory.CurrentSession;

        session.Clear();
    }
}

Then in the service layer:

public void SaveForm(Form form)
{
    _repository.Save(form);

    _uow.Commit();
    _uow.Clear();

    var savedForm = _repository.Get(form.Id);
    SendEmail(savedForm);
}

Update 2

OK, I think I’ve found a suitable solution. I’ve gone back to the transaction-per-request pattern, and after saving the form I’m now flushing it and then evicting the form from the session in order to force NH to get it from the DB.

// Service layer
public void SaveForm(Form form)
{
    _repository.Save(form);

    var savedForm = _repository.Get(form.Id);
    SendEmail(savedForm);
}

// Repository

public void Save(Form form)
{
    var session = SessionFactory.CurrentSession;

    session.SaveOrUpdate(form);
    session.Flush();
    session.Evict(form);
}

Answer 1

Until you flush the session or reduce your transaction scope you won’t have an ID because nhibernate will not have inserted the record.