Question

I have a table of Users and a table of Profiles. One user can have many profiles and a profile can have many users. An additional requirement is that the user’s profiles should persist their specified order when saved to the database. Therefore I have the following relationships:

How can I properly map this to classes with NHibernate? Is the only way to create another class like UserProfile that has an Order property and references the User and Profile? Is there a sleeker technique to this? I’d like to avoid this since it would add another layer of abstraction that isn’t necessarily needed.

Thanks for any suggestions.

Answer 1

I’ve actually found the correct way to solve this problem.

FluentMappings mappings should use AsMap(indexColumnName) or <map name="Profiles"><index column="Order" type="integer" /></map>.

// Inside the UserMapping (or an AutoMappingOverride).
this.ManyToMany(u => u.Profiles).AsMap("`Order`"); // "Order" is the column we want!

// Which produces this SQL - SQLite in my case:
create table ProfileToUser (
    User_id INT not null,
    Profile_id INT not null,
    "Order" INT not null,           // Exactly what I wanted.
    primary key (User_id, Order))