Re: the IN clause saga
От | Barry Lind |
---|---|
Тема | Re: the IN clause saga |
Дата | |
Msg-id | 3F1D7167.3040101@xythos.com обсуждение исходный текст |
Ответ на | Re: the IN clause saga (Felipe Schnack <felipes@ritterdosreis.br>) |
Список | pgsql-jdbc |
No you are not. --Barry Felipe Schnack wrote: > Am I the only the only one who doesn't like the idea of the driver parsing SQL statements (to check if there is a INclause) > > On Tue, 22 Jul 2003 10:41:22 -0400 > Fernando Nasser <fnasser@redhat.com> wrote: > > >>Oliver Jowett wrote: >> >>>On Tue, Jul 22, 2003 at 09:05:45AM -0400, Fernando Nasser wrote: >>> >>> >>>>Thanks for summarizing it Oliver. >>>> >>>>I've asked Tom Lane about the backend behavior and he informed me that: >>>> >>>>1) 7.4 backends do support parameters in the IN predicate, as ($1, $2, >>>>$3) (i.e., our (?, ?, ?) syntax). >>>> >>>>2) 7.4 backends have a PostgreSQL specific extension that allows you to >>>>fill the IN predicate with a list: ($1) (i.e., our (?) ). One has to >>>>pass a PostgreSQL array, like integer[] to fill the list. Note that the >>>>parenthesis is already in place, it is not generated by the ? expansion. >>> >>> >>>I assume this is only when you're doing a PREPARE/EXECUTE? >>> >> >>yes. >> >> >>>>The feature 2 in 7.4 backends is of limited use as the planner does not >>>>know about the list, so the generated plan will not be as good as if you >>>>pass the list with fixed values since the beginning. But an improvement >>>>for this can be attempted for 7.5. >>> >>> >>>Hm, then it sounds like the right solution is to have setArray() expand as >>>the guts of an IN clause when the backend is <7.4 or server prepares are >>>off, and the parameter is in a query of the form "... IN (?)", and as a >>>normal array otherwise. >>> >> >>That is _exactly_ what I am proposing (option 2 of your summary) >> >> >> >>-- >>Fernando Nasser >>Red Hat Canada Ltd. E-Mail: fnasser@redhat.com >>2323 Yonge Street, Suite #300 >>Toronto, Ontario M4P 2C9 >> >> >>---------------------------(end of broadcast)--------------------------- >>TIP 2: you can get off all lists at once with the unregister command >> (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) > > >
В списке pgsql-jdbc по дате отправления: