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activerecord-jdbc-adapter is a database adapter for Rails' ActiveRecord component that can be used with JRuby. It allows use of virtually any JDBC-compliant database with your JRuby on Rails application.


Activerecord-jdbc-adapter provides full or nearly full support for: MySQL, PostgreSQL, SQLite3, Oracle, Microsoft SQL Server, DB2, FireBird, Derby, HSQLDB, H2, and Informix.

Other databases will require testing and likely a custom configuration module. Please join the JRuby mailing-list to help us discover support for more databases.

Using ActiveRecord JDBC

Inside Rails

To use activerecord-jdbc-adapter 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>)
* sqlite3 (<tt>activerecord-jdbcsqlite3-adapter</tt>)
* derby (<tt>activerecord-jdbcderby-adapter</tt>)
* hsqldb (<tt>activerecord-jdbchsqldb-adapter</tt>)
* h2 (<tt>activerecord-jdbch2-adapter</tt>)
* mssql (<tt>activerecord-jdbcmssql-adapter</tt>)

2a. For Rails 3, if you're generating a new application, use the following command to generate your application:

jruby -S rails new sweetapp

2b. Otherwise, you'll need to perform some extra configuration steps to prepare your Rails application for JDBC.

If you're using Rails 3, you'll need to modify your Gemfile to use the activerecord-jdbc-adapter gem under JRuby. Change your Gemfile to look like the following (using sqlite3 as an example):

platforms :ruby do
  gem 'sqlite3'

platforms :jruby do
  gem 'jruby-openssl'
  gem 'activerecord-jdbcsqlite3-adapter'

If you're using Rails 2:

jruby script/generate jdbc
  1. Configure your database.yml in the normal Rails style.

Legacy configuration: If you use one of the convenience 'activerecord-jdbcXXX-adapter' adapters, you can still put a 'jdbc' prefix in front of the database adapter name as below.

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

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

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

For JNDI data sources, you may simply specify the JNDI location as follows
(the adapter will be automatically detected):

   adapter: jdbc
   jndi: jdbc/mysqldb

If you're really old school you might want to use ARJDBC with a DB2 on z/OS.

   adapter: jdbc
   encoding: unicode
   url: jdbc:db2j:net://mightyzoshost:446/RAILS_DBT1
   schema: DB2XB12
   database: RAILS_DB1
   tablespace: TSDE911
     first_table: TSDE912
   username: scott
   password: lion

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

      :adapter => 'jdbcderby',
      :database => "db/my-database"

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

  :adapter => 'jdbc',
  :driver => 'org.apache.derby.jdbc.EmbeddedDriver',
  :url => 'jdbc:derby:test_ar;create=true'

Extending AR-JDBC

You can create your own extension to AR-JDBC for a JDBC-based database that core AR-JDBC does not support. We've created an example project for the Intersystems Cache database that you can examine as a template. See the project for more information at the following URL:

Getting the source

The source for activerecord-jdbc-adapter is available using git.

git clone git://


Please file bug reports at If you're not sure if something's a bug, feel free to pre-report it on the mailing lists.

Project Info

Running AR-JDBC's Tests

Drivers for 6 open-source databases are included. Provided you have MySQL installed, you can simply type jruby -S rake to run the tests. A database named weblog_development is needed beforehand with a connection user of “blog” and an empty password. You alse need to grant “blog” create privileges on 'test_rake_db_create.*'.

If you also have PostgreSQL available, those tests will be run if the `psql' executable can be found. Also ensure you have a database named weblog_development and a user named “blog” and an empty password.

If you want rails logging enabled during these test runs you can edit test/jdbc_common.rb and add the following line:

require 'db/logger'

Running AR Tests

To run the current AR-JDBC sources with ActiveRecord, just use the included “rails:test” task. Be sure to specify a driver and a path to the ActiveRecord sources.

jruby -S rake rails:test DRIVER=mysql RAILS=/path/activerecord_source_dir

Travis Build Status


This project was written by Nick Sieger <> and Ola Bini <> with lots of help from the JRuby community.


activerecord-jdbc-adapter is released under a BSD license. See the LICENSE file included with the distribution for details.

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