yoones / rails-has_many-through-view

Rails has_many through multiple models (using SQL View)

POC goal

This proof-of-concept shows one way to create a has_many through relationship through multiple models.

This answers a question I asked on stackoverflow: (https://stackoverflow.com/questions/49284439/activerecord-has-many-through-two-models/)

Selected solution

Create a UNION SQL view and use it to link projects and investors.

Steps

• Create 4 models: project, investor and join tables subscriptions and external_subscriptions (with basic relationships)
• Make your app dump its database schema in sql format (https://github.com/yoones/rails-has_many-through-view/blob/master/config/application.rb#L14)
• Generate a migration that creates the view using an SQL query (https://github.com/yoones/rails-has_many-through-view/blob/master/db/migrate/20180315083812_create_project_investors.rb)
• Create a model for this new table (https://github.com/yoones/rails-has_many-through-view/blob/master/app/models/project_investor.rb)
• Then add has_many through relationships in models project and investor

Rspec

I wrote specs only for Project model to ensure the relationship works properly.