Re: DBD::PgSQL: More Queestions

On Wed, 20 Nov 2002, Tim Bunce wrote:

> > I notice that
> > DBD::ODBC, for example, doesn't appear to do anything special with
> > regard to comments. And if comments *are* supported by DBI, and DBD::Pg
> > is doing the right thing by watching out for them, wouldn't it be
> > smarter for DBD::Pg to cut them *out* of its internal copy of the SQL
> > statement so that dbd_st_execute() doesn't also have to deal with them?
>
> Why should dbd_st_execute have to "deal" with them? The whole string
> should just be sent off to the server.
>

PostgreSQL itself does not (yet) support placeholders, so DBD::Pg emulates
them by scanning the string again in dbd_st_execute() looking for
placeholders and substituting them quoted values of what was passed to
execute().

or maybe more clearly in pseudo code:

preparse {
look for :pn :0 ? type place holders.
replace with :pn type placehoders.
}

execute {
look for :pn type placeholders
replace with for quote(valueof(:pn))
send to db.
}

-r