rails獲取數據庫表主鍵和序列

#  ActiveRecord::Base.establish_connection(
#      :adapter => 'oracle',
#      :database => 'localhost',
#      :host=>"",
#      :username => 'root',
#      :password => 'root',
#      :encoding => 'gbk'   ## LOOK!
#    )
#    ActiveRecord::Base.connection
#    ActiveRecord::Base.connection.pk_and_sequence_for(:users)