On 07 Jun 2001 14:53:40 -0800, Michael Fowler wrote:
> On Thu, Jun 07, 2001 at 05:27:16PM -0400, Chas Owens wrote:
> > In DBI, it (fetchrow_hashref, not fetchhash) returns a hash where the
> > keys = column names and values = value of the columns on the row. I
> > consider it a generaly bad thing since it forces you to alias your
> > columns when you have two (or more) columns with the same name or an
> > expersion as a column in you result set.
>
> The flipside to this is code maintainability. Consider:
>
> while (defined($row = $sth->fetchrow_arrayref)) {
> print $$row[4];
> }
>
> while (defined($row = $sth->fetchrow_hashref)) {
> print $$row{'permissions'};
> }
>
> Quick, what kind of information is likely to be in the row being printed? :)
>
> Aliasing in the query is easy, and queries (at least in most of my code) are
> fairly static. I'm more often wandering through code trying to figure out
> what's accessing what, and using hashes makes things much easier to
> understand at a glance.
>
>
> Michael
> --
> Administrator www.shoebox.net
> Programmer, System Administrator www.gallanttech.com
> --
I agree; that is the _only_ thing going for fetchrow_hashref (well, that
and if I am going to stuff a hash into a complex data structure anyways).
The other bad thing about fetchrow_hashref is that destroys the order of
the columns. This means you have to rebuild it if, say, you are building
and unload file (pipe delimited). Of course, I am biased since I am an old
ESQL/C programmer and when I don't care about order I tend to use :
$sth = $dbi->prepare($query);
$sth->execute;
while (($id, $name, $permissions) = sth->fetchrow_array) {
do stuff
}
$sth->finish;
compare
$declare GetStuff cursor for :szQuery;
$open GetStuff;
do {
$fetch GetStuff into :iID, :szName, :szPermissions;
if (SQLCODE != 0) { break; }
do stuff
} while (!bTerminate); /*bTerminate set by SIGTERM handler*/
$close GetStuff;
$free GetStuff;
Which is (IMHO) easier to maintain than a hash (the $ref->{} gets on my
nerves). As I get more used to Perl and its idioms I may change that
habit (since array and hash refs are more efficient to pass around).
--
Today is Pungenday, the 12nd day of Confusion in the YOLD 3167
