Say for example we have products and a business rule that every product must have a category. Before ActiveRecord we would have done this with a NOT NULL foreign key constraint at the database level.
It wasn't entirely obvious (to me) how to achieve this in an ActiveRecord model - you need *both* of the following two lines:
Hope this helps someone.
It wasn't entirely obvious (to me) how to achieve this in an ActiveRecord model - you need *both* of the following two lines:
validates_presence_of :category, :message => " must be specified" validates_associated :category
Hope this helps someone.
