Re: the IN clause saga

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 IN clause)

On Tue, 22 Jul 2003 10:41:22 -0400
Fernando Nasser <fnasser(at)redhat(dot)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(at)redhat(dot)com
> 2323 Yonge Street, Suite #300
> Toronto, Ontario M4P 2C9
>
>
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