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package DBIx::SearchBuilder::Unique;
use base 'Exporter';
our @EXPORT = qw(AddRecord);
our $VERSION = "0.01";
use strict;
use warnings;
sub AddRecord {
my $self = shift;
my $record = shift;
# We're a mixin, so we can't override _CleanSlate, but if an object
# gets reused, we need to clean ourselves out. If there are no items,
# we're clearly doing a new search
$self->{"dbix_sb_unique_cache"} = {} unless (@{$self->{'items'}}[0]);
return if $self->{"dbix_sb_unique_cache"}->{$record->id}++;
push @{$self->{'items'}}, $record;
}
1;
=head1 NAME
DBIx::SearchBuilder::Unique - Ensure uniqueness of records in a collection
=head1 SYNOPSIS
package Foo::Collection;
use base 'DBIx::SearchBuilder';
use DBIx::SearchBuilder::Unique; # mixin
my $collection = Foo::Collection->New();
$collection->SetupComplicatedJoins;
$collection->OrderByMagic;
while (my $thing = $collection->Next) {
# $thing is going to be distinct
}
=head1 DESCRIPTION
Currently, DBIx::SearchBuilder makes exceptions for databases which
cannot handle both C<SELECT DISTINCT> and ordering in the same
statement; it drops the C<DISTINCT> requirement. This, of course, means
that you can get the same row twice, which you might not want. If that's
the case, use this module as a mix-in, and it will provide you with an
C<AddRecord> method which ensures that a record will not appear twice in
the same search.
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