Обсуждение: updating records

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updating records

От
Gene Vital
Дата:
Hi all.
     I am using Visual FoxPro via ODBC to update records on a 7.3.4
PostgreSql server and it appears that it always uses delete/insert
instead of updating the current record. Can this be changed to update
the existing record instead?
--
Eugene Vital
Any technology indistinguishable from magic is insufficiently advanced.

Re: updating records

От
Bruno Wolff III
Дата:
On Fri, Oct 03, 2003 at 11:27:11 -0400,
  Gene Vital <genevital@karibe.com> wrote:
> Hi all.
>     I am using Visual FoxPro via ODBC to update records on a 7.3.4
> PostgreSql server and it appears that it always uses delete/insert
> instead of updating the current record. Can this be changed to update
> the existing record instead?

Depneding on why you want to do this, it might not help. Postgres
uses MVCC and updates are effectively inserts and deletes.

Re: updating records

От
"scott.marlowe"
Дата:
On Fri, 3 Oct 2003, Gene Vital wrote:

> Hi all.
>      I am using Visual FoxPro via ODBC to update records on a 7.3.4
> PostgreSql server and it appears that it always uses delete/insert
> instead of updating the current record. Can this be changed to update
> the existing record instead?

I'm not sure if you are saying that Foxpro is doing a delete / insert, or
that postgresql is doing one.

Every update in postgresql is, in fact, a delete / insert, with the delete
delayed until no more transactions are looking at that version of the row
and vacuum has been run.

So, if Visual Foxpro is in fact issuing a delete insert, it's likely no
great performance hit for postgresql, which would wind up doing the same
basic thing anyway.