Teng::Plugin::Minを（コピペしてみた）書いてみた

Teng::Plugin::CountはあるのになんでMinとMaxは無いんだろう？
よくわかってないのでほんとにこれでだいじょうぶなんだろうか・・・。

--- /home/ymko/perl5/lib/perl5/Teng/Plugin/Count.pm     2014-03-15 21:53:40.000000000 +0900
+++ /home/ymko/perl5/lib/perl5/Teng/Plugin/Min.pm       2014-04-13 03:37:45.648043227 +0900
@@ -1,20 +1,20 @@
-package Teng::Plugin::Count;
+package Teng::Plugin::Min;
 use strict;
 use warnings;
 use utf8;

-our @EXPORT = qw/count/;
+our @EXPORT = qw/min/;

-sub count {
+sub min {
     my ($self, $table, $column, $where, $opt) = @_;

     if (ref $column eq 'HASH') {
-        Carp::croak('Do not pass HashRef to second argument. Usage: $db->count($table[, $column[, $where[, $opt]]])');
+        Carp::croak('Do not pass HashRef to second argument. Usage: $db->min($table[, $column[, $where[, $opt]]])');
     }

     $column ||= '*';

-    my ($sql, @binds) = $self->sql_builder->select($table, [\"COUNT($column)"], $where, $opt);
+    my ($sql, @binds) = $self->sql_builder->select($table, [\"MIN($column)"], $where, $opt);

     my ($cnt) = $self->dbh->selectrow_array($sql, {}, @binds);
     return $cnt;

Teng/Plugin/Min.pm

package Teng::Plugin::Min;
use strict;
use warnings;
use utf8;

our @EXPORT = qw/min/;

sub min {
    my ($self, $table, $column, $where, $opt) = @_;

    if (ref $column eq 'HASH') {
        Carp::croak('Do not pass HashRef to second argument. Usage: $db->min($table[, $column[, $where[, $opt]]])');
    }

    $column ||= '*';

    my ($sql, @binds) = $self->sql_builder->select($table, [\"MIN($column)"], $where, $opt);

    my ($cnt) = $self->dbh->selectrow_array($sql, {}, @binds);
    return $cnt;
}

1;

Teng/Plugin/Max.pm

package Teng::Plugin::Max;
use strict;
use warnings;
use utf8;

our @EXPORT = qw/max/;

sub max {
    my ($self, $table, $column, $where, $opt) = @_;

    if (ref $column eq 'HASH') {
        Carp::croak('Do not pass HashRef to second argument. Usage: $db->max($table[, $column[, $where[, $opt]]])');
    }

    $column ||= '*';

    my ($sql, @binds) = $self->sql_builder->select($table, [\"MAX($column)"], $where, $opt);

    my ($cnt) = $self->dbh->selectrow_array($sql, {}, @binds);
    return $cnt;
}
1;

test.pl

#!/usr/bin/env perl
use strict;
use warnings;
use DBI;
use Data::Dumper;
use Teng;
use Teng::Schema::Loader;
Teng->load_plugin('Count');
Teng->load_plugin('Min');
Teng->load_plugin('Max');

my $tbl = "tbl";
my %schema = (
  id  => "integer primary key",
  num => "integer",
);

my $dbh = DBI->connect("dbi:SQLite:dbname=:memory:","","");
my $cmd  = "create table $tbl (";
while (my ($key, $val) = each %schema) {
  $cmd .= " $key $val,";
}
$cmd =~ s/,$//;
$cmd .= ")";
$dbh->do($cmd);

my $teng = Teng::Schema::Loader->load(
  dbh => $dbh,
  namespace => 'MyApp::DB',
);
foreach my $i (10..30) {
  $teng->fast_insert($tbl => {num => $i});
};

print "count=" . $teng->count($tbl, '*') . "\n";
print "  min=" . $teng->min($tbl, 'num') . "\n";
print "  max=" . $teng->count($tbl, 'num') . "\n";
__END__
count=21
  min=10
  max=21