instantiate

Given an attributes hash, instantiate returns a new instance of the appropriate class. Accepts only keys as strings.

For example, Post.all may return Comments, Messages, and Emails by storing the record's subclass in a type attribute. By calling instantiate instead of new, finder methods ensure they get new instances of the appropriate class for each record.

See +ActiveRecord::Inheritance#discriminate_class_for_record+ to see how this âsingle-tableâ inheritance mapping is implemented.