sub mid_set {
my ($self, $num, $mid) = @_;
my $sth = $self->{mid_set} ||= do {
sub mid_set {
my ($self, $num, $mid) = @_;
my $sth = $self->{mid_set} ||= do {
$self->{dbh}->prepare($sql);
};
$sth->execute($num, $mid);
$self->{dbh}->prepare($sql);
};
$sth->execute($num, $mid);