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    <p>The default Rails inheritance model is Single Table Inheritance and is the simplest, cleanest, most generic, and most database-agnostic thing to do.</p> <p>It is accomplished simply by having Answer and Question inherit from Post. Then you create a posts table that has all the fields you want in Post, Answer, and Question. </p> <p>Single Table Inheritance isn't the most space-efficient technique because all rows in the posts table will have <em>all</em> the fields of Post, Answer, and Question. But it is conventional and if you run into space issues down the road you will be in a good position to migrate to a more scalable data model (like Multiple Table Inheritance). And Single Table Inheritance is efficient in the sense that it only requires a single query to find a post by ID, where in other data models there may be an extra query to find what table (post, question, answer) the post is in.</p> <p>As for connecting Comments and Posts, you can use a <code>belongs_to</code> relation in the Comment model that points to Post and a <code>has_many</code> relation in the Post model that points to Comment. (You will need to add a post_id integer field to the comments table to get this to work).</p> <p>cf. <a href="http://guides.rubyonrails.org/association_basics.html" rel="nofollow">http://guides.rubyonrails.org/association_basics.html</a></p> <p>You will also want to add an index for comments on post_id for quickly querying all the comments for a post: <a href="http://guides.rubyonrails.org/migrations.html" rel="nofollow">http://guides.rubyonrails.org/migrations.html</a> .</p>
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    1. POInheritance in Rails databases
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    1. COI don't think it's good practice to start with a non scalable solution which will probably be replaced later on... And then, I would be stuck with the same question... so...
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    2. COSingle Table Inheritance is not "non scalable," it just may add columns to the database. The reason I advise Single Table Inheritance is that it's the conventional way to do inheritance in Rails.
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    3. COYou wrote that maybe somewhere down the road I'll want to "migrate to a more scalable data model". Why not find THAT solution from the beginning?
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