{
    my $SQL;

    BEGIN {
        my @FIELDS = qw( field1 field2 field3 );
        my @PLACEHOLDERS = ('?') x @FIELD;
        local $" = ',';
        $SQL = "INSERT (@FIELDS) INTO foo VALUES (@PLACEHOLDERS)";
    }

    sub run_insert {
        my $dbh = shift || return;
        my $sth = $dbh->prepare($SQL);
        $sth->execute(@_);
        $sth->finish;
    }
}