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POWhat's the most idiomatic way to model this relationship in Rails?
 

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  1. POWhat's the most idiomatic way to model this relationship in Rails?
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    <p>Let's say we have coaches, clients, and users.</p> <p>What's the ideal way to model this in a way that isn't inheritance? I'd like to avoid STI.</p> <p>Right now I have something like this:</p> <p>user.rb</p> <pre><code> has_many :coaches, :foreign_key =&gt; :client_id has_many :coach_users, :through =&gt; :coaches, :source =&gt; :user has_many :clients, :class_name =&gt; "Coach" has_many :client_users, :through =&gt; :clients, :source =&gt; :client def is_a_coach_of?(client) self.client_users.include?(client) end def is_a_client_of?(coach) self.coach_users.include?(coach) end </code></pre> <p>coach.rb</p> <pre><code> belongs_to :user belongs_to :client, :class_name =&gt; "User" </code></pre> <p>But this feels really clunky to deal with a User object that is supposedly a 'coach' and having to type user.coach_users to get a collection of users that are being coached by this specific user.</p> <p>It feels very non idiomatic and quite honestly, it's just plain confusing and I hate it. I want something more elegant. </p> <p>I thought of removing the join model and just having two has_many's on the user.rb model but it still feels clunky, especially the icky feeling of violating roles of objects. These are different roles but are also very similar because they're all a user. How do you separate such common logic in an elegant way, in the right idiomatic way with Rails and Ruby?</p> <p>A "user of the site" <strong>can</strong> exist without being a <code>coach</code> or a <code>client</code>.</p> <p>If the modeling requires just a relationship, then I can see it be a HABTM but what if the individual relationship requires extra logic? E.g extra logic on client or coach? Would you just mixin a class that defines logic in the User model? Or would you create separate AR models for the relationship and if so, how?</p>
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    1. USDaniel Fischer
    1. USDaniel Fischer
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    1. COWhy do you want to avoid using STI? This is a good case for it.
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      1. POWhat's the most idiomatic way to model this relationship in Rails?
      1. USSubstantial
    2. COFrom what I gather, STI is usually a bad solution to the problem but if that's the perfect case...
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      1. POWhat's the most idiomatic way to model this relationship in Rails?
      1. USDaniel Fischer
    3. COSTI works well if done properly despite being very easy to misuse. Note that `User` will become an abstract class and you must only interact with it through it's subclasses. For example, must instantiate a `Coach` or a `Client`, never a `User`. Still, lots of people break that rule, incorporating dirty hacks to curtail Rails' built-in support, get frustrated and write blog posts chastising STI as a "bad solution." If you're willing to give up control of `User`, I'll write up an answer for you.
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      1. USSubstantial
 

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