Fluent NHibernate - need multi-program access to a single, lazy loaded SQLite database

Question

I'm developing a project that has multiple programs that share a single, lazy loaded SQLite database file, using Fluent Nhibernate (Auto Mapping) as the data access layer.

The first program I developed (let's call it Program 1) kept the Session open all the time, and lazy loading worked fine.

This approach failed when I got Program 2 running, and tried to write to the database from Program 2 while Program 1 was running - I got "database locked" exceptions.

I got around this by closing the Session after Program 1 starts up - e.g.

        private ISessionFactory _sessionFactory;
        private ISession _session;

        _sessionFactory = Database.CreateSessionFactory();

        _session = _sessionFactory.OpenSession(); 
        _session.BeginTransaction();

        // ... read the database here

        _session.Close();

Of course, this broke lazy loading in Program 1 when the user selected a different data data set from the user interface - which I had expected.

I thought I would be able to just open the Session again whenever the user selected new data, and then close it again - e.g.

        if ( !_session.IsOpen )
            _session = _sessionFactory.OpenSession();

        if ( !_session.IsConnected )
            _session.Reconnect();

        _session.BeginTransaction();

        // ... read the database here

        _session.Close();

But so far, have not been able to get this to work. I get "no session, or session was closed" exception when I try to read the data, even though I've just opened a session. (The test for the connection was just an experiment, because the exception trace said something about throwing lazy exceptions when disconnected, but it didn't help)

What am I doing wrong?

Answer 1

Is it possible for you to build a service layer which is initiated by the first app to call it (or registered as a windows service if you are on a windows box) and then have everyone call into that service to get their data from?

Im not talking about having a separate server, just a separate service that your programs call into.