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Associations II
Models II

What did we just do? Check out the diagram in the browser:

  1. We created three models - Movie, Actor, and Part.
  2. In the models, we used the has_many :through association to connect the Movie model to the Actor model through the Part model.

In this way, the has_many :through association sets up a many-to-many relationship between movies and actors.

Instructions

1.

Now that there’s an association between Movie and Actor, let’s continue and add columns to the migration files:

Open the migration file in db/migrate/ for the movies table, and add the following columns:

  • a string column called title
  • a string column called image
  • a string column called release_year
  • a string column called plot
2.

Next in the migration file for the actors table, and add the following columns:

  • a string column called first_name
  • a string column called last_name
  • a string column called image
  • a string column called bio
3.

Then in the migration file for the parts table, add the following lines. They add foreign keys that point to the movie and actor tables. 

t.belongs_to :movie, index: true 
t.belongs_to :actor, index: true
4.

Run the migration to update the database with the three tables.

5.

Open up db/seeds.rb. We’ve added a few items here to seed the database with movies and actors. Run bundle exec rake db:seed to seed the database with the data in db/seeds.rb.

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