Getting records back from many to many fluent nhibernate? - nhibernate

Question

I made a many to many relationship by following the fluent nhibernate Getting started tutorial .
(source: fluentnhibernate.org)
Now I am not sure how to retrieve data. For instance what happens if I want to get all the products a store carries.
So I would need to use the storeId on the products table. Yet there is no storeId in the products table and I don't have a class that actually contains mapping or properties for StoreProduct.
So I can't go
session.Query<StoreProduct>().Where(x => x.StoreId == "1").toList();
So do I need to do a join on Store and Products and then do a query on them?
Edit
Here is a watered down version of what I have.
public class Student
{
public virtual Guid StudentId { get; private set; }
public virtual IList<Course> Courses { get; set; }
public virtual IList<Permission> Permissions{get; set;}
public Student()
{
Courses = new List<Course>();
Permissions = new List<Permission>();
}
public class StudentMap : ClassMap<Student>
{
public StudentMap()
{
Table("Students");
Id(x => x.StudentId).Column("StudentId");
HasManyToMany(x => x.Permissions).Table("PermissionLevel");
HasManyToMany(x => x.Courses).Table("PermissionLevel");
}
}
public class CourseMap : ClassMap<Course>
{
public CourseMap()
{
Table("Courses");
Id(x => x.CourseId).Column("CourseId");
HasManyToMany(x => x.Permissions ).Table("PermissionLevel");
HasManyToMany(x => x.Students).Table("PermissionLevel");
}
}
public class Course
{
public virtual int CourseId { get; private set; }
public virtual IList<Permission> Permissions { get; set; }
public virtual IList<Student> Students { get; set; }
public Course()
{
Permissions = new List<Permission>();
Students = new List<Student>();
}
}
public class PermissionMap : ClassMap<Permission>
{
public PermissionMap()
{
Table("Permissions");
Id(x => x.PermissionId).Column("PermissionId");
HasManyToMany(x => x.Students).Table("PermissionLevel");
}
}
public class Permission
{
public virtual int PermissionId { get; private set; }
public virtual IList<Student> Students {get; set;}
public Permission()
{
Students = new List<Student>();
}
}
var a = session.Query<Student>().Where(x => x.Email == email).FirstOrDefault();
var b = session.Get<Student>(a.StudentId).Courses;
error what I get when I look into b.
could not initialize a collection:
[Student.Courses#757f27a2-e997-44f8-b2c2-6c0fd6ee2c2f][SQL:
SELECT courses0_.Student_id as
Student3_1_, courses0_.Course_id as
Course1_1_, course1_.CourseId as
CourseId2_0_, course1_.Prefix as
Prefix2_0_, course1_.BackgroundColor
as Backgrou3_2_0_ FROM PermissionLevel
courses0_ left outer join Courses
course1_ on
courses0_.Course_id=course1_.CourseId
WHERE courses0_.Student_id=?]"

Answer 1

No, you don't. StoreProduct is special table that hold many-to-many relations between Store and Products. NHibernate able to populate Store's collection of products using this table automatically. It should be described in mapping. You should query just like this:
var storeProducts = session.Get<Store>(1).Products;
Here's mapping for Store:
public class StoreMap : ClassMap<Store>
{
public StoreMap()
{
Id(x => x.Id);
Map(x => x.Name);
HasMany(x => x.Staff)
.Inverse()
.Cascade.All();
HasManyToMany(x => x.Products)
.Cascade.All()
.Table("StoreProduct");
}
}
Notice line HasManyToMany(x => x.Products) and .Table("StoreProduct") they tell NHibernate to use table StoreProduct as source for many-to-many relation store objects in collection Products.

Answer 2

You have wrong mappings for Student:
HasManyToMany(x => x.Permissions).Table("PermissionLevel");
HasManyToMany(x => x.Courses).Table("PermissionLevel");
It should be following:
HasManyToMany(x => x.Courses).Table("StudentCourses");
And you Student class is incomplete.