and as Charleton Heston might say:
For the love of God, man... always use a WHERE clause
Really... get in the habit of using WHERE in ALL your SELECT INSERT UPDATE DELETE's... or you will be get burned sooner or later, it is easier to fix one record than the whole DB :-)
Load the results of you query into a perl variable, massage them and THEN open a new connection... and you will do yourself a big favor by just doing some simple error checking:

my $db= new Win32::ODBC("MyDSN") or die "DSN failure, is MyDSN defined
+? Error: ?!";
#Get me everything in the world
$db->Sql("SELECT * from table") or die "SQL Error: $!";
...
[download]

I wonder why you would be given a task that requires you to update if you can't test it on something however... this is really the odd part... Good luck :)