let's imagine this situation.I have a article model and a sort model,and they have a one-to-many association.
the article migration is :
create_table :articles do |t|
t.string :title
t.string :content
t.belongs_to :sort
t.timestamps
end
the sort migration is :
create_table :sorts do |t|
t.string :title
t.timestamps
end
so the article will be added a filed named sort_id.
now,I want to add an index on the filed sort_id in table articles.
whether I can realize as follow:
add_index :articles, :sort, :unique => true
or
add_index :articles, :sort_id, :unique => true