# File lib/active_record/connection_adapters/mysql2_adapter.rb, line 574 def pk_and_sequence_for(table) keys = [] result = execute("SHOW INDEX FROM #{quote_table_name(table)} WHERE Key_name = 'PRIMARY'", 'SCHEMA') result.each(:symbolize_keys => true, :as => :hash) do |row| keys << row[:Column_name] end keys.length == 1 ? [keys.first, nil] : nil end