ActiveRecord JDBC Adapter

ActiveRecord-JDBC-Adapter (AR-JDBC) 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.

AR-JDBC 1.2.x officially supports ActiveRecord 3.x as well as 2.3, it's latest version is compatible with JRuby 1.6.8+ (but as always we recommend to use the latest and greatest of JRubies) thus requires Java 1.6 at minimum.


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 (activerecord-jdbc-adapter) - supports all available databases via JDBC, but requires you to download and manually setup the database vendor's JDBC driver .jar file.
  • MySQL (activerecord-jdbcmysql-adapter)
  • PostgreSQL (activerecord-jdbcpostgresql-adapter)
  • SQLite3 (activerecord-jdbcsqlite3-adapter)
  • Derby (activerecord-jdbcderby-adapter)
  • HSQLDB (activerecord-jdbchsqldb-adapter)
  • H2 (activerecord-jdbch2-adapter)
  • MSSQL (activerecord-jdbcmssql-adapter) - does not support SQL Azure by default, see the README for more information.

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 might 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) :

gem 'sqlite3', :platform => :ruby

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 e.g. :

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

For plain JDBC database configurations, you'll need to know the database driver class and URL (do not forget to put the driver jar on the class-path) e.g. :

  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 correct adapter type will be automatically detected) :

  adapter: jdbc
  jndi: jdbc/mysqldb

JDBC driver specific properties might be set if you use an URL to specify the DB or using the properties: syntax (since AR-JDBC 1.2.6) :

  adapter: mysql
  username: blog
  password: blog
  url: "jdbc:mysql://localhost:3306/weblog?profileSQL=true"
  properties: # specific to com.mysql.jdbc.Driver
    socketTimeout:  60000
    connectTimeout: 60000

If you're really old school you might want to use AR-JDBC 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 the driver gem (dependency) will be installed as well :

jruby -S gem install activerecord-jdbcderby-adapter
  1. After this you can establish a JDBC connection like this :
  :adapter => 'derby', # or 'jdbcderby'
  :database => "db/my-database"

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

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


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

git clone git://

Please note that the project manages multiple gems from a single repository, if you're using Bundler 1.2 it should be able to locate all gemspecs from the git repository. Sample Gemfile for running with (MySQL) master :

gem 'activerecord-jdbc-adapter', :github => 'jruby/activerecord-jdbc-adapter'
gem 'activerecord-jdbcmysql-adapter', :github => 'jruby/activerecord-jdbc-adapter'
gem 'jdbc-mysql', :github => 'jruby/activerecord-jdbc-adapter'

Running AR-JDBC Tests

Build Status

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" with an empty password. You can control the host and port the tests will attempt to by setting the environment variables PGHOST and PGPORT.

To execute a single test case, you can run:

rake appraisal:{version} test_{db} TEST=test/{tests_file}

Substitute the version of ActiveRecord for version, which can be one of : rails23, rails30, rails31, or rails32.

The db can be one of these : sqlite3, mysql, postgres, mssql, sybase, oracle, db2, derby, h2 or hssql.

Finally, the tests_file will be whichever (.rb) test case you want to run.

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 AR's sources :

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

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 cachedb-adapter project for more information.


Please report bugs at our issue tracker. If you're not sure if something's a bug, feel free to pre-report it on the mailing lists or ask on the #JRuby IRC channel on


This project was written by Nick Sieger [email protected] and Ola Bini [email protected] with lots of help from the JRuby community.


ActiveRecord-JDBC-Adapter is released under the BSD/MIT license. See the LICENSE.txt file included with the distribution for details.

Open-source driver gems within AR-JDBC's sources are licensed under the same license the database's drivers are licensed. See each driver gem's LICENSE.txt.