sql_for_insert

# File activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 684
      def sql_for_insert(sql, pk, id_value, sequence_name, binds)
        unless pk
          # Extract the table from the insert sql. Yuck.
          table_ref = extract_table_ref_from_insert_sql(sql)
          pk = primary_key(table_ref) if table_ref
        end

        sql = "#{sql} RETURNING #{quote_column_name(pk)}" if pk

        [sql, binds]
      end