Asymmetrical HABTM(?)

rubyonrails-talk
1

What is the best way to set up a relationship between two tables where table-1 has a one-to-one relationship with table-2 but table-2 has a one-to-many relationship with table-1?

For example, suppose there is an events application (seminars, forums, conferences, etc). Each event has only one address but since many events can occur at the same location throughout the year, a given address can belong to many events.

Thanks, Stan

2

That's just a normal association:

class Event < ActiveRecord::Base    belongs_to :address end

class Address < ActiveRecord::Base    has_many :events end

Don't let the seemingly backward "belongs_to :address" fool you. The 'belongs_to' association is on the model that contains the foreign key (address_id in this example) even though you say "Each event has only one address..." -- the "has ... one" is misleading in this case.

-Rob

Rob Biedenharn http://agileconsultingllc.com Rob@AgileConsultingLLC.com

3

Don't let the seemingly backward "belongs_to :address" fool you. The 'belongs_to' association is on the model that contains the foreign key (address_id in this example) even though you say "Each event has only one address..." -- the "has ... one" is misleading in this case.

Got it. Thanks Rob.

4

That sounds like a plain 1:many to me. Address has_many :events, and Event belongs_to :address.