=head1 DESCRIPTION
-A convenience class used to perform operations on a specific column of a resultset.
+A convenience class used to perform operations on a specific column of
+a resultset.
=cut
my $obj = DBIx::Class::ResultSetColumn->new($rs, $column);
-Creates a new resultset column object from the resultset and column passed as params
+Creates a new resultset column object from the resultset and column
+passed as params. Used internally by L<DBIx::Class::ResultSet/get_column>.
=cut
sub new {
my ($class, $rs, $column) = @_;
$class = ref $class if ref $class;
-
- my $object_ref = { _column => $column,
- _parent_resultset => $rs };
-
- my $new = bless $object_ref, $class;
- $new->throw_exception("column must be supplied") unless ($column);
+ my $new = bless { _column => $column, _parent_resultset => $rs }, $class;
+ $new->throw_exception("column must be supplied") unless $column;
return $new;
}
=back
-Returns the next value of the column in the resultset (C<undef> is there is none).
+Returns the next value of the column in the resultset (or C<undef> if
+there is none).
-Much like $rs->next but just returning the one value
+Much like L<DBIx::Class::ResultSet/next> but just returning the
+one value.
=cut
sub next {
my $self = shift;
-
$self->{_resultset} = $self->{_parent_resultset}->search(undef, {select => [$self->{_column}], as => [$self->{_column}]}) unless ($self->{_resultset});
my ($row) = $self->{_resultset}->cursor->next;
return $row;
=back
-Returns all values of the column in the resultset (C<undef> is there are none).
+Returns all values of the column in the resultset (or C<undef> if
+there are none).
-Much like $rs->all but returns values rather than row objects
+Much like L<DBIx::Class::ResultSet/all> but returns values rather
+than row objects.
=cut
=back
-Wrapper for ->func. Returns the lowest value of the column in the resultset (C<undef> is there are none).
+ my $first_year = $year_col->min();
+
+Wrapper for ->func. Returns the lowest value of the column in the
+resultset (or C<undef> if there are none).
=cut
sub min {
- my $self = shift;
- return $self->func('MIN');
+ return shift->func('MIN');
}
=head2 max
=back
-Wrapper for ->func. Returns the highest value of the column in the resultset (C<undef> is there are none).
+ my $last_year = $year_col->max();
+
+Wrapper for ->func. Returns the highest value of the column in the
+resultset (or C<undef> if there are none).
=cut
sub max {
- my $self = shift;
- return $self->func('MAX');
+ return shift->func('MAX');
}
=head2 sum
=back
-Wrapper for ->func. Returns the sum of all the values in the column of the resultset. Use on varchar-like columns at your own risk.
+ my $total = $prices_col->sum();
+
+Wrapper for ->func. Returns the sum of all the values in the column of
+the resultset. Use on varchar-like columns at your own risk.
=cut
sub sum {
- my $self = shift;
- return $self->func('SUM');
+ return shift->func('SUM');
}
=head2 func
=back
-Runs a query using the function on the column and returns the value. For example
- $rs $schema->resultset("CD")->search({});
- $rs->get_column('title')->func('LENGTH');
+ $rs = $schema->resultset("CD")->search({});
+ $length = $rs->get_column('title')->func('LENGTH');
+
+Runs a query using the function on the column and returns the
+value. Produces the following SQL:
-Produces the following SQL
- SELECT LENGTH( title ) from cd me
+ SELECT LENGTH( title ) FROM cd me
=cut
sub func {
- my $self = shift;
- my $function = shift;
-
+ my ($self,$function) = @_;
my ($row) = $self->{_parent_resultset}->search(undef, {select => {$function => $self->{_column}}, as => [$self->{_column}]})->cursor->next;
return $row;
}
Luke Saunders <luke.saunders@gmail.com>
+Jess Robinson
+
=head1 LICENSE
You may distribute this code under the same terms as Perl itself.