sql_for_insert

# File activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb, line 177
        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

          if pk && use_insert_returning?
            sql = "#{sql} RETURNING #{quote_column_name(pk)}"
          end

          [sql, binds]
        end