Active Record connects business objects and database tables to create
a persistable domain model where logic and data is presented in one
wrapping. It is an implementation of the object-relational mapping
(ORM) pattern by the same name as described by Martin Fowler:
"An object that wraps a row in a database table or view, encapsulates
the database access, and adds domain logic on that data."
Active Records main contribution to the pattern is to relieve the
original of two stunting problems: lack of associations and
inheritance. By adding a simple domain language-like set of macros to
describe the former and integrating the Single Table Inheritance
pattern for the latter, Active Record narrows the gap of functionality
between the data mapper and active record approach.
