Modelling multiple types of users with Devise and Rails 4

I have 3 types of “users”




The last 2 users will have similar attributes such as

First Name

Last Name

and so on

And the Shop user type will have the most contrast between types.

As far as behaviours they will all be quite different, although Provider and Shop will inherent many of customer behaviours.

It seems the behaviours can be dealt with CanCan as I’ve researched.

I’m now attempting to how I should authenticate these types.

I have looked at the STI model but I couldn’t grasp where I would these extra attributes.

My mental model is as follower:

User is a table and model

The types are abstract models that inherit from this.

So I’m wondering, how do I add attributes such as Business address for just the Shop type?

Or is it that the User Table has a column called Type and that type is associated with these type tables? And within the type tables are the extra attributes?

That would be “class table inheritance”. It’s not supported out of the box, but there may be a gem for it.

The “single-table inheritance” that ActiveRecord provides works off a type column in the table, but all the fields are stored on the same table. Some people object to the (possibly) large number of NULL columns in that case, YMMV.

One other thing to consider: in many of the applications I’ve worked on, there’s a logical separation between two pieces that are somewhat mixed together in the above:

  • “how users log in”: this is the various Devise plumbing (email / username, password, confirmation tokens, etc etc)

  • “information about a user”: this is everything else (address, etc)

It can be useful to split these into two classes (and two tables), say “User” and “Profile”. This comes in especially handy when, for instance, a Shop owner requests that her assistant be able to administer the shop as well; this can be cleanly represented by Shop having many Users.

–Matt Jones