Re: Order of Operations for Update Command

Поиск
Список
Период
Сортировка
От Tom Lane
Тема Re: Order of Operations for Update Command
Дата
Msg-id 13643.1472142781@sss.pgh.pa.us
обсуждение исходный текст
Ответ на Order of Operations for Update Command  (simonwhite@dciphercomputing.com)
Список pgsql-docs
simonwhite@dciphercomputing.com writes:
> Does the Update command update the columns in the order they are listed?

Notionally, they're all done concurrently.  This is embodied in our
docs by defining the update source expressions thus:

    An expression to assign to the column. The expression can use the
    old values of this and other columns in the table.

> Can an updated column's new value be used in the value calculation for a
> subsequent column?

No, see above.

            regards, tom lane


В списке pgsql-docs по дате отправления:

Предыдущее
От: simonwhite@dciphercomputing.com
Дата:
Сообщение: Order of Operations for Update Command
Следующее
От: jens.timmerman@gmail.com
Дата:
Сообщение: does md5 really help against sniffing?