my $dbh = DBI->connect(
    $dsn, $user, $password, {
        PrintError => 0,
        RaiseError => 1,
    },
) or die $DBI::errstr;

foreach (@whatever)
{
    eval {
        $dbh->do( $insert_statement, {}, @values );
    }; if ($@) {
        $dbh->do( $update_statement, {}, @values );
    }
}