Rails migration for has_and_belongs_to_many join table

Question

How do I do a script/generate migration to create a join table for a has_and_belongs_to_many relationship?

The application runs on Rails 2.

Answer 1

I like doing:

rails g migration CreateJoinedTable model1:references model2:references. That way I get a migration that looks like this:

class CreateJoinedTable < ActiveRecord::Migration
  def change
    create_table :joined_tables do |t|
      t.references :trip, index: true
      t.references :category, index: true
    end
    add_foreign_key :joined_tables, :trips
    add_foreign_key :joined_tables, :categories
  end
end

I like having index on these columns because I'll often be doing lookups using these columns.