Let’s say you have a
Business class in Rails..and maybe you want to records mergers, so you want to create a
Merger class. Normally, when we create a model, we use the
references type: so rails will automatically create both the
<model>_id fields and the index:
rails g Merger business:references
In this case though, we don’t want to reference just
business, we want to reference the two companies merging. While the generator doesn’t have the capability itself, since Rails 5, it’s easy enough. Run the migration with the references you’d like:
rails g Merger business_one:references business_two:references new_name
Then modify the two reference fields in the migration from this:
t.references :business_one, foreign_key: true
t.references :business_two, foreign_key: true
To this:
t.references :business_one, foreign_key: { to_table: 'businesses' }
t.references :business_two, foreign_key: { to_table: 'businesses' }
