Re: :PgSQL: More Queestions

> >> Maybe it's just too complex, because, looking at DBD::ODBC's
> >> dbd_preparse(), the handling of literals in the query seems a good
> >> deal
> >> more straight-forward (though it doesn't appear to handle '\'' or "\""
> >> -- am I reading that right?
> >
> > Nope, it handles " or '.
> >
> >     if (*src == '"' || *src == '\'') {
> >         etc...
> >     }
>
> It doesn't appear to handle "...""...", though, right? Or am I missing
> it?

Actually, it does, but completely "accidentally".  DBD::ODBC is not
concerned with the fact that there are " inside the ", so:the first quote sets in_literal=1 (true)the second quote sets
in_literal=0(false)the third puts us right back in_literal=1, so we can keep processing.
 
Since there should be an even number of " marks, I think we're OK here.

Seems too simple, but, it works.  There may be a case that gets me, but I
don't think so.

>
>  > My advice: if you don't have to support multiple result sets, do it
> once per
> > execute.  If you setup that "flag" to avoid re-doing work and find
> > that you
> > need to support multiple-result sets, you can always clear the flag...
>
>   I'll have to check with the PostgreSQL folks on this.
>
> PostgreSQL folks, can the same statement return a different number of
> fields on different executes? I'm guessing yes for something like this,
> though:
>
>    CREATE TABLE foo ( bar int, bat, text);
>
>    SELECT * FROM foo;  -- Returns two fields.
>
>    ALTER TABLE foo ADD COLUMN fat int;
>
>    SELECT * FROM foo;  -- Returns three fields.

You probably wouldn't have that prepared as one statement.
Using, say, SQL Server, you can do something like (pseudo code here with
some exaggeration, but I can actually provide test code that someone sent):
sp_pain_to_deal_with(int i) as
    if (i == 1)        select a, b, c from foo;    /* returns a, b, c as result set */    elseif (i == 2)        delete
fromfoo;            /* returns a count, not a result set */    else        select d, a, b, f from foo;    /* returns
somethingcompletely different */end;
 

$sth = $dbh->prepare({ call sp_pain_to_deal_with(?)});
$sth->execute(1);
$sth->execute(2);
$sth->execute(3);

all return different result sets.

Or, the more "normal" case:$sth = $dbh->prepare("insert a, b, c into foo values (?, ?, ?); select
@@identidy;");
which, in one "shot" insert into the table and gets back the
auto-incremented id for the table (again, there is probably a lot of syntax
issue with the above, but the concept is there).



Regards,

Jeff