With Rails 3 you can use
Rails.configuration.database_configuration[Rails.env]
or
Rails.application.config.database_configuration[Rails.env]
or
ActiveRecord::Base.connection_config
With Rails 3 you can use
Rails.configuration.database_configuration[Rails.env]
or
Rails.application.config.database_configuration[Rails.env]
or
ActiveRecord::Base.connection_config