Why no SQL for NHibernate 3 Query?

Why is no SQL being generated when I run my Nhibernate 3 query?

    public IQueryable<Chapter> FindAllChapters()
    {
        using (ISession session = NHibernateHelper.OpenSession())
        {
            var chapte开发者_如何学编程rs = session.QueryOver<Chapter>().List();

            return chapters.AsQueryable();
        }
    }

If I run the query below I can see that the SQL that gets created.

    public IQueryable<Chapter> FindAllChapters()
    {
        using (ISession session = NHibernateHelper.OpenSession())
        {
            var resultDTOs = session.CreateSQLQuery("SELECT Title FROM Chapter")
                    .AddScalar("Title", NHibernateUtil.String)
                    .List();

            // Convert resultDTOs into IQueryable<Chapter>
        }
    }

Linq to NHibernate (like Linq to entities) uses delayed execution. You are returning IQueryable<Chapter> which means that you might add further filtering before using the data, so no query is executed.

If you called .ToList() or .List() (i forget which is in the API), then it would actually produce data and execute the query.

In other words, right now you have an unexecuted query.

Added: Also use Query() not QueryOver(). QueryOver is like detached criteria.

For more info, google "delayed execution linq" for articles like this