NHibernate Linq Startwith generates outer join - nhibernate

Question

I have two entities that are connected through one to many relationship.
like this example:
public class Category
{
public int Id {get; set; }
public string Name {get; set;}
}
public class Product
{
public int Id {get; set;}
public string Name {get; set;}
public Category ProductCategory {get; set;}
}
and the mapping using fluent nhibernate
public class CategoryMap : ClassMap<Category>
{
....
}
public Class ProductMap: ClassMap<Product>
{
...
References(x => x.ProductCategory).Column("CategoryId");
}
When I do search using linq to NHibernate with where clause and equal, it generates inner join between product and category
so this
var query = session.Query<Product>()
.Where (x => x.ProductCategory.Name == "abc");
this will generate inner join
but when I do search with startwith like this
var query = session.Query<Product>()
.Where (x => x.ProductCategory.Name.StartWith("abc"));
this will generate outer join between the two.
Why, and how can I force to generate inner join?

Answer 1

You can do it using QueryOver, which is another method to create query in NHibernate. In that case, you specify the join type as you want.
Category category = null;
var result = session.QueryOver<Product>()
.JoinAlias(x => x.ProductCategory, () => category, JoinType.InnerJoin)
.Where(Restrictions.Like(Projections.Property(() => category.Name), "abc%", MatchMode.Start))
.List();
On the other hand, query over is more verbose code, you have to specify a lot of things you avoid using linq.