= Active Record -- Object-relational mapping put on rails
Active Record connects classes to relational database tables to establish an
almost zero-configuration persistence layer for applications. The library
provides a base class that, when subclassed, sets up a mapping between the new
class and an existing table in the database. In context of an application,
these classes are commonly referred to as *models*. Models can also be
connected to other models; this is done by defining *associations*.
(This is part of Ruby on Rails 3.)
