primary_keys

# File activerecord/lib/active_record/connection_adapters/schema_cache.rb, line 19
      def primary_keys(table_name = nil)
        if table_name
          @primary_keys[table_name]
        else
          ActiveSupport::Deprecation.warn('call primary_keys with a table name!')
          @primary_keys.dup
        end
      end