Re: Question about "compound" queries.
| От | David G. Johnston |
|---|---|
| Тема | Re: Question about "compound" queries. |
| Дата | |
| Msg-id | CAKFQuwbqMTSoptwsyVZtNBds4-96rAJBbt03S3jknsRG_6GSpA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Question about "compound" queries. ("Anton A. Melnikov" <aamelnikov@inbox.ru>) |
| Ответы |
Re: Question about "compound" queries.
|
| Список | pgsql-hackers |
On Mon, Oct 24, 2022 at 3:02 PM Anton A. Melnikov <aamelnikov@inbox.ru> wrote:
Hello!
Please, could somebody explain what the "compound" queries were created for?
Maybe i'm calling them wrong. It's about queries like:
SELECT 1 + 2 \; SELECT 2.0 AS "float" \; SELECT 1;
Such queries can neither be prepared nor used in the extended protocol with
ERROR: cannot insert multiple commands into a prepared statement.
What are their advantages?
And what is the proper name for such queries? "Compound" or something else?
Would be very grateful for clarification.
I suspect they came about out of simplicity - being able to simply take a text file with a bunch of SQL commands in a script and send them as-is to the server without any client-side parsing and let the server just deal with it. It works because the system needs to do those kinds of things anyway so, why not make it user-facing, even if most uses would find its restrictions makes it undesirable to use.
David J.
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