ActiveRecord Without a Database? ActiveRecord Tablefree Models provides a simple mixin for creating models that are not bound to the database. This approach is useful for taking advantage of the features of ActiveRecord such as validation, relationships, nested_attributes, etc. This can also be very useful in testing where a mock-like object will suffice. This gem is exceptionally hacky. For an alternative solution, primarily aimed at testing, that is less hacky, see my other gem anonymous_active_record!