Advanced Rails - Building Industrial-Strength Web Apps in Record Time

Connecting to Multiple Databases | 117

legacy:

adapter: mysql

database: my_db

username: user

password: pass

host: legacy_host

new:

adapter: mysql

database: my_db

username: user

password: pass

host: new_host

Then, you can simply refer to these configuration blocks from the ActiveRecord class
definition using theActiveRecord::Base.establish_connection method:

class LegacyClient < ActiveRecord::Base

establish_connection "legacy"

end

class Client < ActiveRecord::Base

establish_connection "new"

end

This approach also works with multiple Rails environments. Just specify each envi-
ronment in thedatabase.yml file as usual:

legacy_development:

#...

legacy_test:

#...

legacy_production:

#...

new_development:

#...

new_test:

#...

new_production:

#...

Then, use theRAILS_ENV constant in the database configuration block name:

class LegacyClient < ActiveRecord::Base

establish_connection "legacy_#{RAILS_ENV}"

end

class Client < ActiveRecord::Base

establish_connection "new_#{RAILS_ENV}"

end