Question

I’ve just started a project using LINQ to SQL, and I’ve clashed against the many-to-many
problem. I’ve found a lot of possible solution, and I’ve choose this one.

Anyway, the affected db tables look like this:

Customer (idcustomer,other stuff..)
Customer_Role(idcustomer, idrole, other_attribute_I_want_to_keep )
Role(idrole, other stuff)

Now on, how can I handle the “other_attribute_I_want_to_keep?
It would be great to have it like this:

Customer c.Role.other_attribute_I_want_to_keep, but I cannot spot a possible solution.

Thanks

Answer 1

You can’t use many-to-many for this. Rather you’ll need to make CustomerRole a first class object that BelongsTo both a Customer and a Role. Customer and Role in turn should be each declare a HasOne attribute for CustomerRole. Then you can do:

c.CustomerRole.Role
c.CustomerRole.OtherAttribute

You can make a shortcut Role attribute on Customer defined as:

[NotMapped]
public Role Role { 
    get { return CustomerRole == null ? (Role)null : CustomerRole.Role; } 
    set { if (CustomerRole == null)
            CustomerRole = new CustomerRole(){ Role = value };
          else
            CustomerRole.Role = value;
    }
}

but be aware that you may run into trouble using this shortcut when building a complex query.