= Og 0.9.3

Nitro integrates the Og (ObjectGraph) object-relational mapping 
library. Og	provides transparent serialization of object graphs to a RDBMS 
backend. Unlike other similar libraries Og maps standard Ruby
objects to SQL tables and not vice versa. Og provides a meta language
to describe the relations between objects, a flexible	and intuitive api 
for querieng the database, raw access to the SQL language if needed 
(for example to fine tune the automatically generated SQL tables, or 
for custom queries), suports deserialization to Ruby objects or tuples,
automatically generates join tables for many_to_many relations 
and provides a collection of usefull Mixins to synthesize common 
Entities.

Og is a combination of the best features of Active Record and the
former O-R mapping library included in Nitro (NDB). Adapters for
PostgreSQL and MySQL are included.

Og is part of the Nitro project, released as a stand-alone library
due to popular demand. You can find the ChangeLog in the Nitro 
distribution (http://www.rubyforge.com/projects/nitro).


== Features

The library provides the following features:

+ Object-Relational mapping.
+ Absolutely no configuration files.
+ Multiple backends (PostgreSQL, MySQL).
+ ActiveRecord-style meta language and db aware methods.
+ Automatially generates join-tables for many_to_many relations.
+ Deserialize to Ruby Objects or ResultSets.
+ Deserialize sql join queries to Ruby Objects.
+ Serialize arbitrary ruby object graphs through YAML.
+ Connection pooling.
+ Thread safety.
+ SQL transactions.
+ Lifecycle callbacks.
+ Transparent support for cascading deletes for all backends.
+ Hierarchical structures (preorder traversal, materialized paths)
+ Works safely as part of distributed application.
+ Automatic Validation/Constraints.
+ Simple and clean implementation.

== Download

The latest version of Og can be found at

* http://www.rubyforge.com/projects/nitro

Documentation for Og can be found in the distribution.


== Requirements

Og requires the following applications or libraries:

* Ruby 1.8.1 and greater 
	http://www.ruby-lang.org
	Version 1.8.2 is recomended.

* Ruby-psql 
	http://www.postgresql.jp/interfaces/ruby/archive/ruby-postgres-0.7.1.tar.gz
	Ruby interface to the PostgreSQL RDBMS.

* Ruby-mysql 
	http://tmtm.org/ja/ruby/mysql/README_en.html
	Ruby interface to the MySQL RDBMS.
	
* PostgreSQL 
	http://www.postgres.org
	Used for the Database Backend.
	
* MySQL 
	http://www.mysql.org
	Used for the Database Backend.

Please install the required applications and libraries before continuing
with the installation of Og. Only install the libraries needed for
the backend you plan to use.


== Instalation

Og is distributed as a RubyGem. First of all make sure you have
installed RubyGems on your system. Then run the following command:

gem install og

Then try to run the examples/og Example application.

A tar.gz distribution is also available on http://www.rubyforge.com/projects/nitro.


== Support

For any questions regarding Og, feel free to ask on the ruby-talk 
mailing list (which is mirrored to comp.lang.ruby) or contact 
mailto:gm@navel.gr.


== Licence

Copyright (c) 2004-2005 Navel Ltd (http://www.navel.gr)

Og (http://www.navel.gr/og) is copyrighted free software
created and maintained by George Moschovitis (mailto:gm@navel.gr)
and released under the standard BSD Licence. For details consult
the file LICENCE.