= Og 0.23.0 README

Og (ObjectGraph) is a powerful and elegant object-relational mapping 
library. Og manages the lifecycle of Ruby objects and  provides 
transparent serialization of object graphs to stores (typically
RDBM systems)/.

Unlike other similar solutions Og maps standard Ruby objects 
to SQL tables and not vice versa. Og provides a domain specific 
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), provides automatic 
validation, 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.

Adapters for PostgreSQL, MySQL, SQLite3, Memory, Filesystem,
Oracle and SQL Server 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.nitrohq.com).


== Features

The library provides the following features:

* Object-Relational mapping, automatically maps standard 
  Ruby objects to sql schemas
* Absolutely no configuration files.
* Multiple stores (PostgreSQL, MySQL, SQLite, Oraclei, SqlServer, ..).
* Supports non SQL stores (in-memory, filesystem, ..).
* Can 'reverse engineer' legacy database schemase.
* Fine-grained or High-level customization of the generated
  schema.
* ActiveRecord-style domain specific language and db synchronized
  collections.
* Transforms resultsets from arbitrary sql queries to Ruby objects.
* Independent store for each object class, can support multiple
  stores in the same application.
* Deserialize to Ruby Objects.
* Deserialize sql join queries to Ruby Objects.
* Eager associations.
* Serialize arbitrary ruby object graphs through YAML.
* Connection pooling.
* Thread safety.
* SQL transactions.
* Aspect oriented constructs allow interception of lifecycle callbacks.
* Transparent support for cascading deletes for all backends.
* Hierarchical structures (nested sets)
* Works safely as part of distributed application.
* Optimistic locking.
* Simple implementation.


== What's new

For information about the latest changes please consult the
file

doc/RELEASES


== Download

The latest version of Og can be found at

* http://www.nitrohq.com

== Documentation

Documentation for Og can be found at

* http://www.nitrohq.com

Don't forget to read the file doc/RELEASES for usefull
documentation bits. Also, have a look at the test cases in
the test directory for examples of usage.

You can find a nice tutorial at www.rubygarden.com. Be warned
that this tutorial describes an earlier version of Og. A *LOT*
of new features have been added in the meantime.


== 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.
  Pure Ruby Mysql interface:
  http://www.tmtm.org/ruby/mysql/
  
* PostgreSQL 
  http://www.postgres.org
  Used for the Database Backend.
  
* MySQL 
  http://www.mysql.org
  Used for the Database Backend.

* SQLite
  http://www.sqlite.org/download.html
  WARNING: you need sqlite3-ruby > 1.1.0

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

(make sure you have the latest stable versions of Ruby and RubyGems
installed)

Then try to run the examples in the examples directory.

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


== Examples:

Some examples can be found in the examples directory. You are also
encouraged to check out the unit tests. Especially the test:

test/og/tc_store.rb

demonstrates some advanced features of Og.


== 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.

An Og specific mailing list is also available. Please subscribe
to nitro-general@rubyforge.com. The homepage for this list
is available here:

http://rubyforge.org/mailman/listinfo/nitro-general


== Licence

Copyright (c) 2004-2005, Navel Ltd (http://www.navel.gr)
Copyright (c) 2004-2005, George 'gmosx' Moschovitis (http://www.gmosx.com).

Og (http://www.nitrohq.com) 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.