ActiveRecord-JDBC is a database adapter for Rails' ActiveRecord component that can be used with 
JRuby[http://www.jruby.org/].  It allows use of virtually any JDBC-compliant database with your JRuby on Rails 
application.

ActiveRecord-JDBC is a sub-project of jruby-extras at RubyForge.

== Databases

What's there, and what is not there:

* MySQL - Complete support
* PostgreSQL - Complete support
* Oracle - Complete support
* Microsoft SQL Server - Complete support except for change_column_default
* DB2 - Complete, except for the migrations:
  * change_column 
  * change_column_default
  * remove_column
  * rename_column
  * add_index
  * remove_index
  * rename_table
* FireBird - Complete, except for change_column_default and rename_column
* Derby - Complete, except for:
  * change_column
  * change_column_default
  * remove_column
  * rename_column
* HSQLDB - Complete
* H2 - Complete
* SQLite3 - work in progress

Other databases will require testing and likely a custom configuration module. Please join the jruby-extras 
mailing-list[http://rubyforge.org/mail/?group_id=2014] to help us discover support for more databases.

== Using ActiveRecord JDBC

=== Inside Rails

To use ActiveRecord-JDBC with JRuby on Rails:

1. Choose the adapter you wish to gem install.  The following pre-packaged adapters are available:

  * base jdbc (<tt>activerecord-jdbc-adapter</tt>). Supports all available databases via JDBC, but requires you to 
  download and manually install the database vendor's JDBC driver .jar file.
  * mysql (<tt>activerecord-jdbcmysql-adapter</tt>)
  * postgresql (<tt>activerecord-jdbcpostgresql-adapter</tt>)
  * derby (<tt>activerecord-jdbcderby-adapter</tt>)
  * hsqldb (<tt>activerecord-jdbchsqldb-adapter</tt>)
  * h2 (<tt>activerecord-jdbch2-adapter</tt>)

2. If you're using Rails 2.0, you may skip to the next step. For Rails prior to version 2.0, you'll need to add one-time 
setup to your config/environment.rb file in your Rails application. Add the following lines just before the 
<code>Rails::Initializer</code>. (If you're using ActiveRecord-JDBC under the old gem name used in versions 0.5 and 
earlier, replace 'activerecord-jdbc-adapter' with 'ActiveRecord-JDBC' below.)

    if RUBY_PLATFORM =~ /java/
      require 'rubygems'
      gem 'activerecord-jdbc-adapter'
      require 'jdbc_adapter'
    end

3. Configure your database.yml to use the <code>jdbc</code> adapter.
For mysql, postgres, derby, oracle, hsqldb and h2 you can simply configure the database in the normal Rails style. If 
you use one of the convenience 'activerecord-jdbcXXX-adapter' adapters, be sure and put a 'jdbc' prefix in front of the 
databas adapter name as below.

    development:
      adapter: jdbcmysql
      username: blog
      password:
      hostname: localhost
      database: weblog_development

For other databases, you'll need to know the database driver class and URL.  Example:

    development:
      adapter: jdbc
      username: blog
      password:
      driver: com.mysql.jdbc.Driver
      url: jdbc:mysql://localhost:3306/weblog_development

=== Standalone, with ActiveRecord

1. Install the gem with JRuby:

    jruby -S gem install activerecord-jdbc-adapter

   If you wish to use the adapter for a specific database, you can install it directly and a driver gem will be 
   installed as well:

    jruby -S gem install activerecord-jdbcderby-adapter

2. If using ActiveRecord 2.0 (Rails 2.0) or greater, you can skip to the next step. Otherwise, ensure the following code 
gets executed in your script:

    require 'rubygems'
    gem 'activerecord-jdbc-adapter'
    require 'jdbc_adapter'
    require 'active_record'

3. After this you can establish a JDBC connection like this:

    ActiveRecord::Base.establish_connection(
      :adapter => 'jdbcderby',
      :database => "db/my-database"
    )

   or like this (but requires that you manually put the driver jar on the classpath):

    ActiveRecord::Base.establish_connection(
      :adapter => 'jdbc',
      :driver => 'org.apache.derby.jdbc.EmbeddedDriver',
      :url => 'jdbc:derby:test_ar;create=true'
    )

== Running AR-JDBC's Tests

Drivers for 4 open-source databases are included.  Provided you have MySQL installed, you can simply type <tt>jruby -S 
rake</tt> to run the tests.  A database named <tt>weblog_development</tt> is needed beforehand with a connection user of 
"blog" and password empty.

== Authors

This project was written by Nick Sieger <nick@nicksieger.com> and Ola Bini <ola@ologix.com> with lots of help from the 
JRuby community.

== License

ActiveRecord-JDBC is released under a BSD license.  See the LICENSE file included with the distribution for details.

Open-source driver gems for ActiveRecord JDBC are licensed under the same license the database's drivers are licensed.  
See each driver gem's LICENSE.txt file for details.