I have an Opportunity model that belongs_to Section model. Section has_many opportunities.
class Opportunity < ActiveRecord::Base
belongs_to :section
class Section < ActiveRecord::Base
has_many :opportunities
Opportunity model has to have section_id but i would like to be able to also have many sections as involved sections in some cases.
how would it be possible to create? thanks
You need a many-to-many association between, Opportunity and Section, for that you need to create a connecting table between the two, create a migration
create_table :opportunities_sections, id: false do |t|
t.belongs_to :opportunity
t.belongs_to :section
end
Then in Opportunity model, add this line
has_and_belongs_to_many :sections
In Section model, add this line
has_and_belongs_to_many :opportunities
Finally, remove section_id column from opportunities table.
More info on has_and_belongs_to_many association here
https://guides.rubyonrails.org/association_basics.html#the-has-and-belongs-to-many-association
You can also achieve many-to-many association via has_many through association, the basic difference between has_and_belongs_to_many and has_many through is you can create a model class for the connecting table, that way you get more flexibility in terms of saving any additional data with the connection. More info here
https://guides.rubyonrails.org/association_basics.html#the-has-many-through-association
What to choose?
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