fluent nhibernate - Many to Many mapping with attribute

Question

I have 2 master tables which are linked by a map table as below

User [UserId,Name]

Resource [ResourceId,Name]

UserResourceMap [UserId,ResourceId,AccessLeve         


        

Answer 1

As you've correctly identified in your database schema, this isn't a pure many-to-many relationship - it's two one-to-many relationships as the intermediate table has an attribute (the access level).

I therefore think your domain is missing an entity - there doesn't appear to be any relationship in your model between a user and the resources they can access.

How about something like this:

public class User
{
    public virtual int Id { get;protected set; }
    public virtual string Name { get;set; }
    public virtual ICollection UserResources { get; set;}
}

public class UserResource
{
    public virtual int Id { get; protected set; }
    public virtual User User { get; set;}
    public virtual Resource Resource { get; set;}
    public virtual string AccessLevel { get; set;}
}

public class Resource
{
    public virtual int Id { get;protected set; }
    public virtual string Name { get;set; }
}

And mappings like:

public class UserMap : ClassMap
{
    public UserMap()
    {
        Id(x => x.Id);
        Map(x => x.Name);
        HasMany(x => x.UserResource)
            .AsSet()
            .Inverse()
            .Cascade.AllDeleteOrphan();
    }
}

public class UserResourceMap : ClassMap
{
    public UserResourceMap()
    {
        Table("UserResourceMap");
        Id(x => x.Id);
        References(x => x.User).Not.Nullable();
        References(x => x.Resource).Not.Nullable();
        Map(x => x.AccessLevel);
    }
}

public class ResourceMap : ClassMap
{
    public ResourceMap()
    {
        Cache.ReadOnly();

        Id(x => x.Id);
        Map(x => x.Name);
    }
}