Fluent NHibernate does not create IN part of WHERE clause

Question

I have Fluent NHibernate Linq queries where I check values based on run time arrays. A basic example would be something like:

var array = [1,2,3,4,5,6];
usin         


        

Answer 1

Does it make a difference if you change your Query method to the following ?

public IList<T> Query(Expression<Func<T, bool>> criteria)
{
  using (var session = SessionProvider.SessionFactory.OpenSession())
  {
    return session.Query<T>().Where(criteria).ToList();
  }
}

---

This is how I usually proceed with a generic Query :

    public List<TOut> GetEntitiesLinq<TIn,TOut>(Expression<Func<IQueryable<TIn>,IQueryable<TOut>>> myFunc)
    {
        var t = (myFunc.Compile())(_session.Query<TIn>()) ;
        return t.ToList();
    }

Then how I would use it in your case :

var myObjList = myQueryManager.GetEntitiesLinq<MyObject,MyObject>(x=>x.Where(myObj => array.Contains(myObj.CompareVal)));

Hope this will help

Answer 2

Can you use QueryOver and WhereRestrictionOn instead?

session.QueryOver<MyObject>().WhereRestrictionOn(o => o.CompareVal).IsIn(array).List();

Answer 3

Use Any:

 return session.Query<MyObject>().Where(x => array.Any(y => y == x.CompareVal)).ToList();

Your repository pattern (using plain Func) automatically materializes your query to list, if you want something to be deferredly executed, use IQueryable, don't use Func only

Something to note - I have a Generic Repository class that all of these calls are funneled through. The Query method is as follows:

public IList<T> Query(Func<T, bool> criteria)
{
  using (var session = SessionProvider.SessionFactory.OpenSession())
  {
    return session.Query<T>().Where(criteria).ToList();
  }
}

Your repository just mimic what is already provided out of the box by NHibernate