my $sql = 'exec OSP_FOO_BAR( ?, ?, ? )';
my $sth = $dbh->prepare($sql);
$sth->execute($xvar, $yvar, $zvar);
$dbh->commit();

##</code><code>##

$_ = $dbh->quote($_) foreach $xvar, $yvar, $zvar; # foreach aliases $_
$SQLString = "exec OSP_FOO_BAR( $xvar, $yvar, $zvar )";
$dbh->do($SQLString);      
$dbh->commit();