Question

I’m modelling a scenario with Users and Tools, where a Tool is owned by one User but can be used by many Users including to one owning it.

I was thinking about adding an owner_id column to Tools and say it has_many Users or by adding a new relationsship table.

I’m really new to Rails and I have problems setting up the right associations in the models though, maybe you can point me in the right direction?

Thank you very much.

Answer 1

Your should add owner_id to the Tools table.
Associations will be like that.

class User < ActiveRecord::Base
  has_and_belongs_to_many :tools
end

class Tool < ActiveRecord::Base
  has_and_belongs_to_many :users
  belongs_to :owner, :class_name => 'User'
end

You’ll need a tools_users table in order to use habtm-association. Generate a migration and create a table with option id: false and two columns user_id and tool_id:

class CreateToolsUsersTable < ActiveRecordMigration
  def change
    create_table :tools_users, id: false do |t|
      t.integer :tool_id
      t.integer :user_id
    end
  end
end

After that you can call something like @user.tools or @user.owner
Read more there