1 package DBIx::Class::ResultSet;
9 use Carp::Clan qw/^DBIx::Class/;
12 use DBIx::Class::ResultSetColumn;
13 use DBIx::Class::ResultSourceHandle;
14 use base qw/DBIx::Class/;
16 __PACKAGE__->mk_group_accessors('simple' => qw/result_class _source_handle/);
20 DBIx::Class::ResultSet - Responsible for fetching and creating resultset.
24 my $rs = $schema->resultset('User')->search(registered => 1);
25 my @rows = $schema->resultset('CD')->search(year => 2005);
29 The resultset is also known as an iterator. It is responsible for handling
30 queries that may return an arbitrary number of rows, e.g. via L</search>
31 or a C<has_many> relationship.
33 In the examples below, the following table classes are used:
35 package MyApp::Schema::Artist;
36 use base qw/DBIx::Class/;
37 __PACKAGE__->load_components(qw/Core/);
38 __PACKAGE__->table('artist');
39 __PACKAGE__->add_columns(qw/artistid name/);
40 __PACKAGE__->set_primary_key('artistid');
41 __PACKAGE__->has_many(cds => 'MyApp::Schema::CD');
44 package MyApp::Schema::CD;
45 use base qw/DBIx::Class/;
46 __PACKAGE__->load_components(qw/Core/);
47 __PACKAGE__->table('cd');
48 __PACKAGE__->add_columns(qw/cdid artist title year/);
49 __PACKAGE__->set_primary_key('cdid');
50 __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Artist');
59 =item Arguments: $source, \%$attrs
61 =item Return Value: $rs
65 The resultset constructor. Takes a source object (usually a
66 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
67 L</ATTRIBUTES> below). Does not perform any queries -- these are
68 executed as needed by the other methods.
70 Generally you won't need to construct a resultset manually. You'll
71 automatically get one from e.g. a L</search> called in scalar context:
73 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
75 IMPORTANT: If called on an object, proxies to new_result instead so
77 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
79 will return a CD object, not a ResultSet.
85 return $class->new_result(@_) if ref $class;
87 my ($source, $attrs) = @_;
88 $source = $source->handle
89 unless $source->isa('DBIx::Class::ResultSourceHandle');
90 $attrs = { %{$attrs||{}} };
93 $attrs->{rows} ||= 10;
94 $attrs->{offset} ||= 0;
95 $attrs->{offset} += ($attrs->{rows} * ($attrs->{page} - 1));
98 $attrs->{alias} ||= 'me';
101 _source_handle => $source,
102 result_class => $attrs->{result_class} || $source->resolve->result_class,
103 cond => $attrs->{where},
118 =item Arguments: $cond, \%attrs?
120 =item Return Value: $resultset (scalar context), @row_objs (list context)
124 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
125 my $new_rs = $cd_rs->search({ year => 2005 });
127 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
128 # year = 2005 OR year = 2004
130 If you need to pass in additional attributes but no additional condition,
131 call it as C<search(undef, \%attrs)>.
133 # "SELECT name, artistid FROM $artist_table"
134 my @all_artists = $schema->resultset('Artist')->search(undef, {
135 columns => [qw/name artistid/],
138 For a list of attributes that can be passed to C<search>, see
139 L</ATTRIBUTES>. For more examples of using this function, see
140 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
141 documentation for the first argument, see L<SQL::Abstract>.
147 my $rs = $self->search_rs( @_ );
148 return (wantarray ? $rs->all : $rs);
155 =item Arguments: $cond, \%attrs?
157 =item Return Value: $resultset
161 This method does the same exact thing as search() except it will
162 always return a resultset, even in list context.
171 unless (@_) { # no search, effectively just a clone
172 $rows = $self->get_cache;
176 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
177 my $our_attrs = { %{$self->{attrs}} };
178 my $having = delete $our_attrs->{having};
179 my $where = delete $our_attrs->{where};
181 my $new_attrs = { %{$our_attrs}, %{$attrs} };
183 # merge new attrs into inherited
184 foreach my $key (qw/join prefetch/) {
185 next unless exists $attrs->{$key};
186 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
191 (@_ == 1 || ref $_[0] eq "HASH")
193 (ref $_[0] eq 'HASH')
195 (keys %{ $_[0] } > 0)
203 ? $self->throw_exception("Odd number of arguments to search")
210 if (defined $where) {
211 $new_attrs->{where} = (
212 defined $new_attrs->{where}
215 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
216 } $where, $new_attrs->{where}
223 $new_attrs->{where} = (
224 defined $new_attrs->{where}
227 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
228 } $cond, $new_attrs->{where}
234 if (defined $having) {
235 $new_attrs->{having} = (
236 defined $new_attrs->{having}
239 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
240 } $having, $new_attrs->{having}
246 my $rs = (ref $self)->new($self->_source_handle, $new_attrs);
248 $rs->set_cache($rows);
253 =head2 search_literal
257 =item Arguments: $sql_fragment, @bind_values
259 =item Return Value: $resultset (scalar context), @row_objs (list context)
263 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
264 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
266 Pass a literal chunk of SQL to be added to the conditional part of the
272 my ($self, $cond, @vals) = @_;
273 my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
274 $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ];
275 return $self->search(\$cond, $attrs);
282 =item Arguments: @values | \%cols, \%attrs?
284 =item Return Value: $row_object
288 Finds a row based on its primary key or unique constraint. For example, to find
289 a row by its primary key:
291 my $cd = $schema->resultset('CD')->find(5);
293 You can also find a row by a specific unique constraint using the C<key>
294 attribute. For example:
296 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
297 key => 'cd_artist_title'
300 Additionally, you can specify the columns explicitly by name:
302 my $cd = $schema->resultset('CD')->find(
304 artist => 'Massive Attack',
305 title => 'Mezzanine',
307 { key => 'cd_artist_title' }
310 If the C<key> is specified as C<primary>, it searches only on the primary key.
312 If no C<key> is specified, it searches on all unique constraints defined on the
313 source, including the primary key.
315 If your table does not have a primary key, you B<must> provide a value for the
316 C<key> attribute matching one of the unique constraints on the source.
318 See also L</find_or_create> and L</update_or_create>. For information on how to
319 declare unique constraints, see
320 L<DBIx::Class::ResultSource/add_unique_constraint>.
326 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
328 # Default to the primary key, but allow a specific key
329 my @cols = exists $attrs->{key}
330 ? $self->result_source->unique_constraint_columns($attrs->{key})
331 : $self->result_source->primary_columns;
332 $self->throw_exception(
333 "Can't find unless a primary key is defined or unique constraint is specified"
336 # Parse out a hashref from input
338 if (ref $_[0] eq 'HASH') {
339 $input_query = { %{$_[0]} };
341 elsif (@_ == @cols) {
343 @{$input_query}{@cols} = @_;
346 # Compatibility: Allow e.g. find(id => $value)
347 carp "Find by key => value deprecated; please use a hashref instead";
351 my (%related, $info);
353 foreach my $key (keys %$input_query) {
354 if (ref($input_query->{$key})
355 && ($info = $self->result_source->relationship_info($key))) {
356 my $rel_q = $self->result_source->resolve_condition(
357 $info->{cond}, delete $input_query->{$key}, $key
359 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
360 @related{keys %$rel_q} = values %$rel_q;
363 if (my @keys = keys %related) {
364 @{$input_query}{@keys} = values %related;
367 my @unique_queries = $self->_unique_queries($input_query, $attrs);
369 # Build the final query: Default to the disjunction of the unique queries,
370 # but allow the input query in case the ResultSet defines the query or the
371 # user is abusing find
372 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
373 my $query = @unique_queries
374 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
375 : $self->_add_alias($input_query, $alias);
379 my $rs = $self->search($query, $attrs);
380 return keys %{$rs->_resolved_attrs->{collapse}} ? $rs->next : $rs->single;
383 return keys %{$self->_resolved_attrs->{collapse}}
384 ? $self->search($query)->next
385 : $self->single($query);
391 # Add the specified alias to the specified query hash. A copy is made so the
392 # original query is not modified.
395 my ($self, $query, $alias) = @_;
397 my %aliased = %$query;
398 foreach my $col (grep { ! m/\./ } keys %aliased) {
399 $aliased{"$alias.$col"} = delete $aliased{$col};
407 # Build a list of queries which satisfy unique constraints.
409 sub _unique_queries {
410 my ($self, $query, $attrs) = @_;
412 my @constraint_names = exists $attrs->{key}
414 : $self->result_source->unique_constraint_names;
416 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
417 my $num_where = scalar keys %$where;
420 foreach my $name (@constraint_names) {
421 my @unique_cols = $self->result_source->unique_constraint_columns($name);
422 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
424 my $num_cols = scalar @unique_cols;
425 my $num_query = scalar keys %$unique_query;
427 my $total = $num_query + $num_where;
428 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
429 # The query is either unique on its own or is unique in combination with
430 # the existing where clause
431 push @unique_queries, $unique_query;
435 return @unique_queries;
438 # _build_unique_query
440 # Constrain the specified query hash based on the specified column names.
442 sub _build_unique_query {
443 my ($self, $query, $unique_cols) = @_;
446 map { $_ => $query->{$_} }
447 grep { exists $query->{$_} }
452 =head2 search_related
456 =item Arguments: $rel, $cond, \%attrs?
458 =item Return Value: $new_resultset
462 $new_rs = $cd_rs->search_related('artist', {
466 Searches the specified relationship, optionally specifying a condition and
467 attributes for matching records. See L</ATTRIBUTES> for more information.
472 return shift->related_resultset(shift)->search(@_);
479 =item Arguments: none
481 =item Return Value: $cursor
485 Returns a storage-driven cursor to the given resultset. See
486 L<DBIx::Class::Cursor> for more information.
493 my $attrs = { %{$self->_resolved_attrs} };
494 return $self->{cursor}
495 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
496 $attrs->{where},$attrs);
503 =item Arguments: $cond?
505 =item Return Value: $row_object?
509 my $cd = $schema->resultset('CD')->single({ year => 2001 });
511 Inflates the first result without creating a cursor if the resultset has
512 any records in it; if not returns nothing. Used by L</find> as an optimisation.
514 Can optionally take an additional condition *only* - this is a fast-code-path
515 method; if you need to add extra joins or similar call ->search and then
516 ->single without a condition on the $rs returned from that.
521 my ($self, $where) = @_;
522 my $attrs = { %{$self->_resolved_attrs} };
524 if (defined $attrs->{where}) {
527 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
528 $where, delete $attrs->{where} ]
531 $attrs->{where} = $where;
535 # XXX: Disabled since it doesn't infer uniqueness in all cases
536 # unless ($self->_is_unique_query($attrs->{where})) {
537 # carp "Query not guaranteed to return a single row"
538 # . "; please declare your unique constraints or use search instead";
541 my @data = $self->result_source->storage->select_single(
542 $attrs->{from}, $attrs->{select},
543 $attrs->{where}, $attrs
546 return (@data ? ($self->_construct_object(@data))[0] : ());
551 # Try to determine if the specified query is guaranteed to be unique, based on
552 # the declared unique constraints.
554 sub _is_unique_query {
555 my ($self, $query) = @_;
557 my $collapsed = $self->_collapse_query($query);
558 my $alias = $self->{attrs}{alias};
560 foreach my $name ($self->result_source->unique_constraint_names) {
561 my @unique_cols = map {
563 } $self->result_source->unique_constraint_columns($name);
565 # Count the values for each unique column
566 my %seen = map { $_ => 0 } @unique_cols;
568 foreach my $key (keys %$collapsed) {
569 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
570 next unless exists $seen{$aliased}; # Additional constraints are okay
571 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
574 # If we get 0 or more than 1 value for a column, it's not necessarily unique
575 return 1 unless grep { $_ != 1 } values %seen;
583 # Recursively collapse the query, accumulating values for each column.
585 sub _collapse_query {
586 my ($self, $query, $collapsed) = @_;
590 if (ref $query eq 'ARRAY') {
591 foreach my $subquery (@$query) {
592 next unless ref $subquery; # -or
593 # warn "ARRAY: " . Dumper $subquery;
594 $collapsed = $self->_collapse_query($subquery, $collapsed);
597 elsif (ref $query eq 'HASH') {
598 if (keys %$query and (keys %$query)[0] eq '-and') {
599 foreach my $subquery (@{$query->{-and}}) {
600 # warn "HASH: " . Dumper $subquery;
601 $collapsed = $self->_collapse_query($subquery, $collapsed);
605 # warn "LEAF: " . Dumper $query;
606 foreach my $col (keys %$query) {
607 my $value = $query->{$col};
608 $collapsed->{$col}{$value}++;
620 =item Arguments: $cond?
622 =item Return Value: $resultsetcolumn
626 my $max_length = $rs->get_column('length')->max;
628 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
633 my ($self, $column) = @_;
634 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
642 =item Arguments: $cond, \%attrs?
644 =item Return Value: $resultset (scalar context), @row_objs (list context)
648 # WHERE title LIKE '%blue%'
649 $cd_rs = $rs->search_like({ title => '%blue%'});
651 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
652 that this is simply a convenience method. You most likely want to use
653 L</search> with specific operators.
655 For more information, see L<DBIx::Class::Manual::Cookbook>.
661 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
662 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
663 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
664 return $class->search($query, { %$attrs });
671 =item Arguments: $first, $last
673 =item Return Value: $resultset (scalar context), @row_objs (list context)
677 Returns a resultset or object list representing a subset of elements from the
678 resultset slice is called on. Indexes are from 0, i.e., to get the first
681 my ($one, $two, $three) = $rs->slice(0, 2);
686 my ($self, $min, $max) = @_;
687 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
688 $attrs->{offset} = $self->{attrs}{offset} || 0;
689 $attrs->{offset} += $min;
690 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
691 return $self->search(undef(), $attrs);
692 #my $slice = (ref $self)->new($self->result_source, $attrs);
693 #return (wantarray ? $slice->all : $slice);
700 =item Arguments: none
702 =item Return Value: $result?
706 Returns the next element in the resultset (C<undef> is there is none).
708 Can be used to efficiently iterate over records in the resultset:
710 my $rs = $schema->resultset('CD')->search;
711 while (my $cd = $rs->next) {
715 Note that you need to store the resultset object, and call C<next> on it.
716 Calling C<< resultset('Table')->next >> repeatedly will always return the
717 first record from the resultset.
723 if (my $cache = $self->get_cache) {
724 $self->{all_cache_position} ||= 0;
725 return $cache->[$self->{all_cache_position}++];
727 if ($self->{attrs}{cache}) {
728 $self->{all_cache_position} = 1;
729 return ($self->all)[0];
731 if ($self->{stashed_objects}) {
732 my $obj = shift(@{$self->{stashed_objects}});
733 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
737 exists $self->{stashed_row}
738 ? @{delete $self->{stashed_row}}
739 : $self->cursor->next
741 return unless (@row);
742 my ($row, @more) = $self->_construct_object(@row);
743 $self->{stashed_objects} = \@more if @more;
747 sub _construct_object {
748 my ($self, @row) = @_;
749 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
750 my @new = $self->result_class->inflate_result($self->_source_handle, @$info);
751 @new = $self->{_attrs}{record_filter}->(@new)
752 if exists $self->{_attrs}{record_filter};
756 sub _collapse_result {
757 my ($self, $as, $row, $prefix) = @_;
762 foreach my $this_as (@$as) {
763 my $val = shift @copy;
764 if (defined $prefix) {
765 if ($this_as =~ m/^\Q${prefix}.\E(.+)$/) {
767 $remain =~ /^(?:(.*)\.)?([^.]+)$/;
768 $const{$1||''}{$2} = $val;
771 $this_as =~ /^(?:(.*)\.)?([^.]+)$/;
772 $const{$1||''}{$2} = $val;
776 my $alias = $self->{attrs}{alias};
777 my $info = [ {}, {} ];
778 foreach my $key (keys %const) {
779 if (length $key && $key ne $alias) {
781 my @parts = split(/\./, $key);
782 foreach my $p (@parts) {
783 $target = $target->[1]->{$p} ||= [];
785 $target->[0] = $const{$key};
787 $info->[0] = $const{$key};
792 if (defined $prefix) {
794 m/^\Q${prefix}.\E(.+)$/ ? ($1) : ()
795 } keys %{$self->{_attrs}{collapse}}
797 @collapse = keys %{$self->{_attrs}{collapse}};
801 my ($c) = sort { length $a <=> length $b } @collapse;
803 foreach my $p (split(/\./, $c)) {
804 $target = $target->[1]->{$p} ||= [];
806 my $c_prefix = (defined($prefix) ? "${prefix}.${c}" : $c);
807 my @co_key = @{$self->{_attrs}{collapse}{$c_prefix}};
808 my $tree = $self->_collapse_result($as, $row, $c_prefix);
809 my %co_check = map { ($_, $tree->[0]->{$_}); } @co_key;
815 !defined($tree->[0]->{$_}) || $co_check{$_} ne $tree->[0]->{$_}
820 last unless (@raw = $self->cursor->next);
821 $row = $self->{stashed_row} = \@raw;
822 $tree = $self->_collapse_result($as, $row, $c_prefix);
824 @$target = (@final ? @final : [ {}, {} ]);
825 # single empty result to indicate an empty prefetched has_many
828 #print "final info: " . Dumper($info);
836 =item Arguments: $result_source?
838 =item Return Value: $result_source
842 An accessor for the primary ResultSource object from which this ResultSet
849 =item Arguments: $result_class?
851 =item Return Value: $result_class
855 An accessor for the class to use when creating row objects. Defaults to
856 C<< result_source->result_class >> - which in most cases is the name of the
857 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
866 =item Arguments: $cond, \%attrs??
868 =item Return Value: $count
872 Performs an SQL C<COUNT> with the same query as the resultset was built
873 with to find the number of elements. If passed arguments, does a search
874 on the resultset and counts the results of that.
876 Note: When using C<count> with C<group_by>, L<DBIX::Class> emulates C<GROUP BY>
877 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
878 not support C<DISTINCT> with multiple columns. If you are using such a
879 database, you should only use columns from the main table in your C<group_by>
886 return $self->search(@_)->count if @_ and defined $_[0];
887 return scalar @{ $self->get_cache } if $self->get_cache;
888 my $count = $self->_count;
889 return 0 unless $count;
891 $count -= $self->{attrs}{offset} if $self->{attrs}{offset};
892 $count = $self->{attrs}{rows} if
893 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
897 sub _count { # Separated out so pager can get the full count
899 my $select = { count => '*' };
901 my $attrs = { %{$self->_resolved_attrs} };
902 if (my $group_by = delete $attrs->{group_by}) {
903 delete $attrs->{having};
904 my @distinct = (ref $group_by ? @$group_by : ($group_by));
905 # todo: try CONCAT for multi-column pk
906 my @pk = $self->result_source->primary_columns;
908 my $alias = $attrs->{alias};
909 foreach my $column (@distinct) {
910 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
911 @distinct = ($column);
917 $select = { count => { distinct => \@distinct } };
920 $attrs->{select} = $select;
921 $attrs->{as} = [qw/count/];
923 # offset, order by and page are not needed to count. record_filter is cdbi
924 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
926 my $tmp_rs = (ref $self)->new($self->_source_handle, $attrs);
927 my ($count) = $tmp_rs->cursor->next;
935 =item Arguments: $sql_fragment, @bind_values
937 =item Return Value: $count
941 Counts the results in a literal query. Equivalent to calling L</search_literal>
942 with the passed arguments, then L</count>.
946 sub count_literal { shift->search_literal(@_)->count; }
952 =item Arguments: none
954 =item Return Value: @objects
958 Returns all elements in the resultset. Called implicitly if the resultset
959 is returned in list context.
965 return @{ $self->get_cache } if $self->get_cache;
969 # TODO: don't call resolve here
970 if (keys %{$self->_resolved_attrs->{collapse}}) {
971 # if ($self->{attrs}{prefetch}) {
972 # Using $self->cursor->all is really just an optimisation.
973 # If we're collapsing has_many prefetches it probably makes
974 # very little difference, and this is cleaner than hacking
975 # _construct_object to survive the approach
976 my @row = $self->cursor->next;
978 push(@obj, $self->_construct_object(@row));
979 @row = (exists $self->{stashed_row}
980 ? @{delete $self->{stashed_row}}
981 : $self->cursor->next);
984 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
987 $self->set_cache(\@obj) if $self->{attrs}{cache};
995 =item Arguments: none
997 =item Return Value: $self
1001 Resets the resultset's cursor, so you can iterate through the elements again.
1007 delete $self->{_attrs} if exists $self->{_attrs};
1008 $self->{all_cache_position} = 0;
1009 $self->cursor->reset;
1017 =item Arguments: none
1019 =item Return Value: $object?
1023 Resets the resultset and returns an object for the first result (if the
1024 resultset returns anything).
1029 return $_[0]->reset->next;
1032 # _cond_for_update_delete
1034 # update/delete require the condition to be modified to handle
1035 # the differing SQL syntax available. This transforms the $self->{cond}
1036 # appropriately, returning the new condition.
1038 sub _cond_for_update_delete {
1039 my ($self, $full_cond) = @_;
1042 $full_cond ||= $self->{cond};
1043 # No-op. No condition, we're updating/deleting everything
1044 return $cond unless ref $full_cond;
1046 if (ref $full_cond eq 'ARRAY') {
1050 foreach my $key (keys %{$_}) {
1052 $hash{$1} = $_->{$key};
1058 elsif (ref $full_cond eq 'HASH') {
1059 if ((keys %{$full_cond})[0] eq '-and') {
1062 my @cond = @{$full_cond->{-and}};
1063 for (my $i = 0; $i < @cond; $i++) {
1064 my $entry = $cond[$i];
1067 if (ref $entry eq 'HASH') {
1068 $hash = $self->_cond_for_update_delete($entry);
1071 $entry =~ /([^.]+)$/;
1072 $hash->{$1} = $cond[++$i];
1075 push @{$cond->{-and}}, $hash;
1079 foreach my $key (keys %{$full_cond}) {
1081 $cond->{$1} = $full_cond->{$key};
1086 $self->throw_exception(
1087 "Can't update/delete on resultset with condition unless hash or array"
1099 =item Arguments: \%values
1101 =item Return Value: $storage_rv
1105 Sets the specified columns in the resultset to the supplied values in a
1106 single query. Return value will be true if the update succeeded or false
1107 if no records were updated; exact type of success value is storage-dependent.
1112 my ($self, $values) = @_;
1113 $self->throw_exception("Values for update must be a hash")
1114 unless ref $values eq 'HASH';
1116 my $cond = $self->_cond_for_update_delete;
1118 return $self->result_source->storage->update(
1119 $self->result_source, $values, $cond
1127 =item Arguments: \%values
1129 =item Return Value: 1
1133 Fetches all objects and updates them one at a time. Note that C<update_all>
1134 will run DBIC cascade triggers, while L</update> will not.
1139 my ($self, $values) = @_;
1140 $self->throw_exception("Values for update must be a hash")
1141 unless ref $values eq 'HASH';
1142 foreach my $obj ($self->all) {
1143 $obj->set_columns($values)->update;
1152 =item Arguments: none
1154 =item Return Value: 1
1158 Deletes the contents of the resultset from its result source. Note that this
1159 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1160 to run. See also L<DBIx::Class::Row/delete>.
1167 my $cond = $self->_cond_for_update_delete;
1169 $self->result_source->storage->delete($self->result_source, $cond);
1177 =item Arguments: none
1179 =item Return Value: 1
1183 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1184 will run DBIC cascade triggers, while L</delete> will not.
1190 $_->delete for $self->all;
1198 =item Arguments: none
1200 =item Return Value: $pager
1204 Return Value a L<Data::Page> object for the current resultset. Only makes
1205 sense for queries with a C<page> attribute.
1211 my $attrs = $self->{attrs};
1212 $self->throw_exception("Can't create pager for non-paged rs")
1213 unless $self->{attrs}{page};
1214 $attrs->{rows} ||= 10;
1215 return $self->{pager} ||= Data::Page->new(
1216 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1223 =item Arguments: $page_number
1225 =item Return Value: $rs
1229 Returns a resultset for the $page_number page of the resultset on which page
1230 is called, where each page contains a number of rows equal to the 'rows'
1231 attribute set on the resultset (10 by default).
1236 my ($self, $page) = @_;
1237 return (ref $self)->new($self->_source_handle, { %{$self->{attrs}}, page => $page });
1244 =item Arguments: \%vals
1246 =item Return Value: $object
1250 Creates an object in the resultset's result class and returns it.
1255 my ($self, $values) = @_;
1256 $self->throw_exception( "new_result needs a hash" )
1257 unless (ref $values eq 'HASH');
1258 $self->throw_exception(
1259 "Can't abstract implicit construct, condition not a hash"
1260 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1262 my $alias = $self->{attrs}{alias};
1263 my $collapsed_cond = $self->{cond} ? $self->_collapse_cond($self->{cond}) : {};
1265 %{ $self->_remove_alias($values, $alias) },
1266 %{ $self->_remove_alias($collapsed_cond, $alias) },
1269 return $self->result_class->new(\%new,$self->_source_handle);
1274 # Recursively collapse the condition.
1276 sub _collapse_cond {
1277 my ($self, $cond, $collapsed) = @_;
1281 if (ref $cond eq 'ARRAY') {
1282 foreach my $subcond (@$cond) {
1283 next unless ref $subcond; # -or
1284 # warn "ARRAY: " . Dumper $subcond;
1285 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1288 elsif (ref $cond eq 'HASH') {
1289 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1290 foreach my $subcond (@{$cond->{-and}}) {
1291 # warn "HASH: " . Dumper $subcond;
1292 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1296 # warn "LEAF: " . Dumper $cond;
1297 foreach my $col (keys %$cond) {
1298 my $value = $cond->{$col};
1299 $collapsed->{$col} = $value;
1309 # Remove the specified alias from the specified query hash. A copy is made so
1310 # the original query is not modified.
1313 my ($self, $query, $alias) = @_;
1315 my %orig = %{ $query || {} };
1318 foreach my $key (keys %orig) {
1320 $unaliased{$key} = $orig{$key};
1323 $unaliased{$1} = $orig{$key}
1324 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1334 =item Arguments: \%vals, \%attrs?
1336 =item Return Value: $object
1340 Find an existing record from this resultset. If none exists, instantiate a new
1341 result object and return it. The object will not be saved into your storage
1342 until you call L<DBIx::Class::Row/insert> on it.
1344 If you want objects to be saved immediately, use L</find_or_create> instead.
1350 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1351 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1352 my $exists = $self->find($hash, $attrs);
1353 return defined $exists ? $exists : $self->new_result($hash);
1360 =item Arguments: \%vals
1362 =item Return Value: $object
1366 Inserts a record into the resultset and returns the object representing it.
1368 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1373 my ($self, $attrs) = @_;
1374 $self->throw_exception( "create needs a hashref" )
1375 unless ref $attrs eq 'HASH';
1376 return $self->new_result($attrs)->insert;
1379 =head2 find_or_create
1383 =item Arguments: \%vals, \%attrs?
1385 =item Return Value: $object
1389 $class->find_or_create({ key => $val, ... });
1391 Tries to find a record based on its primary key or unique constraint; if none
1392 is found, creates one and returns that instead.
1394 my $cd = $schema->resultset('CD')->find_or_create({
1396 artist => 'Massive Attack',
1397 title => 'Mezzanine',
1401 Also takes an optional C<key> attribute, to search by a specific key or unique
1402 constraint. For example:
1404 my $cd = $schema->resultset('CD')->find_or_create(
1406 artist => 'Massive Attack',
1407 title => 'Mezzanine',
1409 { key => 'cd_artist_title' }
1412 See also L</find> and L</update_or_create>. For information on how to declare
1413 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1417 sub find_or_create {
1419 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1420 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1421 my $exists = $self->find($hash, $attrs);
1422 return defined $exists ? $exists : $self->create($hash);
1425 =head2 update_or_create
1429 =item Arguments: \%col_values, { key => $unique_constraint }?
1431 =item Return Value: $object
1435 $class->update_or_create({ col => $val, ... });
1437 First, searches for an existing row matching one of the unique constraints
1438 (including the primary key) on the source of this resultset. If a row is
1439 found, updates it with the other given column values. Otherwise, creates a new
1442 Takes an optional C<key> attribute to search on a specific unique constraint.
1445 # In your application
1446 my $cd = $schema->resultset('CD')->update_or_create(
1448 artist => 'Massive Attack',
1449 title => 'Mezzanine',
1452 { key => 'cd_artist_title' }
1455 If no C<key> is specified, it searches on all unique constraints defined on the
1456 source, including the primary key.
1458 If the C<key> is specified as C<primary>, it searches only on the primary key.
1460 See also L</find> and L</find_or_create>. For information on how to declare
1461 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1465 sub update_or_create {
1467 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1468 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
1470 my $row = $self->find($cond, $attrs);
1472 $row->update($cond);
1476 return $self->create($cond);
1483 =item Arguments: none
1485 =item Return Value: \@cache_objects?
1489 Gets the contents of the cache for the resultset, if the cache is set.
1501 =item Arguments: \@cache_objects
1503 =item Return Value: \@cache_objects
1507 Sets the contents of the cache for the resultset. Expects an arrayref
1508 of objects of the same class as those produced by the resultset. Note that
1509 if the cache is set the resultset will return the cached objects rather
1510 than re-querying the database even if the cache attr is not set.
1515 my ( $self, $data ) = @_;
1516 $self->throw_exception("set_cache requires an arrayref")
1517 if defined($data) && (ref $data ne 'ARRAY');
1518 $self->{all_cache} = $data;
1525 =item Arguments: none
1527 =item Return Value: []
1531 Clears the cache for the resultset.
1536 shift->set_cache(undef);
1539 =head2 related_resultset
1543 =item Arguments: $relationship_name
1545 =item Return Value: $resultset
1549 Returns a related resultset for the supplied relationship name.
1551 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
1555 sub related_resultset {
1556 my ($self, $rel) = @_;
1558 $self->{related_resultsets} ||= {};
1559 return $self->{related_resultsets}{$rel} ||= do {
1560 my $rel_obj = $self->result_source->relationship_info($rel);
1562 $self->throw_exception(
1563 "search_related: result source '" . $self->_source_handle->source_moniker .
1564 "' has no such relationship $rel")
1567 my ($from,$seen) = $self->_resolve_from($rel);
1569 my $join_count = $seen->{$rel};
1570 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
1572 $self->_source_handle->schema->resultset($rel_obj->{class})->search_rs(
1574 %{$self->{attrs}||{}},
1580 where => $self->{cond},
1588 my ($self, $extra_join) = @_;
1589 my $source = $self->result_source;
1590 my $attrs = $self->{attrs};
1592 my $from = $attrs->{from}
1593 || [ { $attrs->{alias} => $source->from } ];
1595 my $seen = { %{$attrs->{seen_join}||{}} };
1597 my $join = ($attrs->{join}
1598 ? [ $attrs->{join}, $extra_join ]
1602 ($join ? $source->resolve_join($join, $attrs->{alias}, $seen) : ()),
1605 return ($from,$seen);
1608 sub _resolved_attrs {
1610 return $self->{_attrs} if $self->{_attrs};
1612 my $attrs = { %{$self->{attrs}||{}} };
1613 my $source = $self->result_source;
1614 my $alias = $attrs->{alias};
1616 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
1617 if ($attrs->{columns}) {
1618 delete $attrs->{as};
1619 } elsif (!$attrs->{select}) {
1620 $attrs->{columns} = [ $source->columns ];
1625 ? (ref $attrs->{select} eq 'ARRAY'
1626 ? [ @{$attrs->{select}} ]
1627 : [ $attrs->{select} ])
1628 : [ map { m/\./ ? $_ : "${alias}.$_" } @{delete $attrs->{columns}} ]
1632 ? (ref $attrs->{as} eq 'ARRAY'
1633 ? [ @{$attrs->{as}} ]
1635 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{$attrs->{select}} ]
1639 if ($adds = delete $attrs->{include_columns}) {
1640 $adds = [$adds] unless ref $adds eq 'ARRAY';
1641 push(@{$attrs->{select}}, @$adds);
1642 push(@{$attrs->{as}}, map { m/([^.]+)$/; $1 } @$adds);
1644 if ($adds = delete $attrs->{'+select'}) {
1645 $adds = [$adds] unless ref $adds eq 'ARRAY';
1646 push(@{$attrs->{select}},
1647 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds);
1649 if (my $adds = delete $attrs->{'+as'}) {
1650 $adds = [$adds] unless ref $adds eq 'ARRAY';
1651 push(@{$attrs->{as}}, @$adds);
1654 $attrs->{from} ||= [ { 'me' => $source->from } ];
1656 if (exists $attrs->{join} || exists $attrs->{prefetch}) {
1657 my $join = delete $attrs->{join} || {};
1659 if (defined $attrs->{prefetch}) {
1660 $join = $self->_merge_attr(
1661 $join, $attrs->{prefetch}
1665 $attrs->{from} = # have to copy here to avoid corrupting the original
1668 $source->resolve_join($join, $alias, { %{$attrs->{seen_join}||{}} })
1672 $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
1673 if ($attrs->{order_by}) {
1674 $attrs->{order_by} = (ref($attrs->{order_by}) eq 'ARRAY'
1675 ? [ @{$attrs->{order_by}} ]
1676 : [ $attrs->{order_by} ]);
1678 $attrs->{order_by} = [];
1681 my $collapse = $attrs->{collapse} || {};
1682 if (my $prefetch = delete $attrs->{prefetch}) {
1683 $prefetch = $self->_merge_attr({}, $prefetch);
1685 my $seen = $attrs->{seen_join} || {};
1686 foreach my $p (ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch)) {
1687 # bring joins back to level of current class
1688 my @prefetch = $source->resolve_prefetch(
1689 $p, $alias, $seen, \@pre_order, $collapse
1691 push(@{$attrs->{select}}, map { $_->[0] } @prefetch);
1692 push(@{$attrs->{as}}, map { $_->[1] } @prefetch);
1694 push(@{$attrs->{order_by}}, @pre_order);
1696 $attrs->{collapse} = $collapse;
1698 return $self->{_attrs} = $attrs;
1702 my ($self, $a, $b) = @_;
1703 return $b unless defined($a);
1704 return $a unless defined($b);
1706 if (ref $b eq 'HASH' && ref $a eq 'HASH') {
1707 foreach my $key (keys %{$b}) {
1708 if (exists $a->{$key}) {
1709 $a->{$key} = $self->_merge_attr($a->{$key}, $b->{$key});
1711 $a->{$key} = $b->{$key};
1716 $a = [$a] unless ref $a eq 'ARRAY';
1717 $b = [$b] unless ref $b eq 'ARRAY';
1721 foreach my $x ($a, $b) {
1722 foreach my $element (@{$x}) {
1723 if (ref $element eq 'HASH') {
1724 $hash = $self->_merge_attr($hash, $element);
1725 } elsif (ref $element eq 'ARRAY') {
1726 push(@array, @{$element});
1728 push(@array, $element) unless $b == $x
1729 && grep { $_ eq $element } @array;
1734 @array = grep { !exists $hash->{$_} } @array;
1736 return keys %{$hash}
1749 $self->_source_handle($_[0]->handle);
1751 $self->_source_handle->resolve;
1755 =head2 throw_exception
1757 See L<DBIx::Class::Schema/throw_exception> for details.
1761 sub throw_exception {
1763 $self->_source_handle->schema->throw_exception(@_);
1766 # XXX: FIXME: Attributes docs need clearing up
1770 The resultset takes various attributes that modify its behavior. Here's an
1777 =item Value: ($order_by | \@order_by)
1781 Which column(s) to order the results by. This is currently passed
1782 through directly to SQL, so you can give e.g. C<year DESC> for a
1783 descending order on the column `year'.
1785 Please note that if you have C<quote_char> enabled (see
1786 L<DBIx::Class::Storage::DBI/connect_info>) you will need to do C<\'year DESC' > to
1787 specify an order. (The scalar ref causes it to be passed as raw sql to the DB,
1788 so you will need to manually quote things as appropriate.)
1794 =item Value: \@columns
1798 Shortcut to request a particular set of columns to be retrieved. Adds
1799 C<me.> onto the start of any column without a C<.> in it and sets C<select>
1800 from that, then auto-populates C<as> from C<select> as normal. (You may also
1801 use the C<cols> attribute, as in earlier versions of DBIC.)
1803 =head2 include_columns
1807 =item Value: \@columns
1811 Shortcut to include additional columns in the returned results - for example
1813 $schema->resultset('CD')->search(undef, {
1814 include_columns => ['artist.name'],
1818 would return all CDs and include a 'name' column to the information
1819 passed to object inflation. Note that the 'artist' is the name of the
1820 column (or relationship) accessor, and 'name' is the name of the column
1821 accessor in the related table.
1827 =item Value: \@select_columns
1831 Indicates which columns should be selected from the storage. You can use
1832 column names, or in the case of RDBMS back ends, function or stored procedure
1835 $rs = $schema->resultset('Employee')->search(undef, {
1838 { count => 'employeeid' },
1843 When you use function/stored procedure names and do not supply an C<as>
1844 attribute, the column names returned are storage-dependent. E.g. MySQL would
1845 return a column named C<count(employeeid)> in the above example.
1851 Indicates additional columns to be selected from storage. Works the same as
1852 L<select> but adds columns to the selection.
1860 Indicates additional column names for those added via L<+select>.
1868 =item Value: \@inflation_names
1872 Indicates column names for object inflation. That is, c< as >
1873 indicates the name that the column can be accessed as via the
1874 C<get_column> method (or via the object accessor, B<if one already
1875 exists>). It has nothing to do with the SQL code C< SELECT foo AS bar
1878 The C< as > attribute is used in conjunction with C<select>,
1879 usually when C<select> contains one or more function or stored
1882 $rs = $schema->resultset('Employee')->search(undef, {
1885 { count => 'employeeid' }
1887 as => ['name', 'employee_count'],
1890 my $employee = $rs->first(); # get the first Employee
1892 If the object against which the search is performed already has an accessor
1893 matching a column name specified in C<as>, the value can be retrieved using
1894 the accessor as normal:
1896 my $name = $employee->name();
1898 If on the other hand an accessor does not exist in the object, you need to
1899 use C<get_column> instead:
1901 my $employee_count = $employee->get_column('employee_count');
1903 You can create your own accessors if required - see
1904 L<DBIx::Class::Manual::Cookbook> for details.
1906 Please note: This will NOT insert an C<AS employee_count> into the SQL
1907 statement produced, it is used for internal access only. Thus
1908 attempting to use the accessor in an C<order_by> clause or similar
1909 will fail miserably.
1911 To get around this limitation, you can supply literal SQL to your
1912 C<select> attibute that contains the C<AS alias> text, eg:
1914 select => [\'myfield AS alias']
1920 =item Value: ($rel_name | \@rel_names | \%rel_names)
1924 Contains a list of relationships that should be joined for this query. For
1927 # Get CDs by Nine Inch Nails
1928 my $rs = $schema->resultset('CD')->search(
1929 { 'artist.name' => 'Nine Inch Nails' },
1930 { join => 'artist' }
1933 Can also contain a hash reference to refer to the other relation's relations.
1936 package MyApp::Schema::Track;
1937 use base qw/DBIx::Class/;
1938 __PACKAGE__->table('track');
1939 __PACKAGE__->add_columns(qw/trackid cd position title/);
1940 __PACKAGE__->set_primary_key('trackid');
1941 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
1944 # In your application
1945 my $rs = $schema->resultset('Artist')->search(
1946 { 'track.title' => 'Teardrop' },
1948 join => { cd => 'track' },
1949 order_by => 'artist.name',
1953 You need to use the relationship (not the table) name in conditions,
1954 because they are aliased as such. The current table is aliased as "me", so
1955 you need to use me.column_name in order to avoid ambiguity. For example:
1957 # Get CDs from 1984 with a 'Foo' track
1958 my $rs = $schema->resultset('CD')->search(
1961 'tracks.name' => 'Foo'
1963 { join => 'tracks' }
1966 If the same join is supplied twice, it will be aliased to <rel>_2 (and
1967 similarly for a third time). For e.g.
1969 my $rs = $schema->resultset('Artist')->search({
1970 'cds.title' => 'Down to Earth',
1971 'cds_2.title' => 'Popular',
1973 join => [ qw/cds cds/ ],
1976 will return a set of all artists that have both a cd with title 'Down
1977 to Earth' and a cd with title 'Popular'.
1979 If you want to fetch related objects from other tables as well, see C<prefetch>
1986 =item Value: ($rel_name | \@rel_names | \%rel_names)
1990 Contains one or more relationships that should be fetched along with the main
1991 query (when they are accessed afterwards they will have already been
1992 "prefetched"). This is useful for when you know you will need the related
1993 objects, because it saves at least one query:
1995 my $rs = $schema->resultset('Tag')->search(
2004 The initial search results in SQL like the following:
2006 SELECT tag.*, cd.*, artist.* FROM tag
2007 JOIN cd ON tag.cd = cd.cdid
2008 JOIN artist ON cd.artist = artist.artistid
2010 L<DBIx::Class> has no need to go back to the database when we access the
2011 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2014 Simple prefetches will be joined automatically, so there is no need
2015 for a C<join> attribute in the above search. If you're prefetching to
2016 depth (e.g. { cd => { artist => 'label' } or similar), you'll need to
2017 specify the join as well.
2019 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2020 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2021 with an accessor type of 'single' or 'filter').
2031 Makes the resultset paged and specifies the page to retrieve. Effectively
2032 identical to creating a non-pages resultset and then calling ->page($page)
2035 If L<rows> attribute is not specified it defualts to 10 rows per page.
2045 Specifes the maximum number of rows for direct retrieval or the number of
2046 rows per page if the page attribute or method is used.
2052 =item Value: $offset
2056 Specifies the (zero-based) row number for the first row to be returned, or the
2057 of the first row of the first page if paging is used.
2063 =item Value: \@columns
2067 A arrayref of columns to group by. Can include columns of joined tables.
2069 group_by => [qw/ column1 column2 ... /]
2075 =item Value: $condition
2079 HAVING is a select statement attribute that is applied between GROUP BY and
2080 ORDER BY. It is applied to the after the grouping calculations have been
2083 having => { 'count(employee)' => { '>=', 100 } }
2089 =item Value: (0 | 1)
2093 Set to 1 to group by all columns.
2099 Adds to the WHERE clause.
2101 # only return rows WHERE deleted IS NULL for all searches
2102 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2104 Can be overridden by passing C<{ where => undef }> as an attribute
2111 Set to 1 to cache search results. This prevents extra SQL queries if you
2112 revisit rows in your ResultSet:
2114 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2116 while( my $artist = $resultset->next ) {
2120 $rs->first; # without cache, this would issue a query
2122 By default, searches are not cached.
2124 For more examples of using these attributes, see
2125 L<DBIx::Class::Manual::Cookbook>.
2131 =item Value: \@from_clause
2135 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
2136 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
2139 NOTE: Use this on your own risk. This allows you to shoot off your foot!
2141 C<join> will usually do what you need and it is strongly recommended that you
2142 avoid using C<from> unless you cannot achieve the desired result using C<join>.
2143 And we really do mean "cannot", not just tried and failed. Attempting to use
2144 this because you're having problems with C<join> is like trying to use x86
2145 ASM because you've got a syntax error in your C. Trust us on this.
2147 Now, if you're still really, really sure you need to use this (and if you're
2148 not 100% sure, ask the mailing list first), here's an explanation of how this
2151 The syntax is as follows -
2154 { <alias1> => <table1> },
2156 { <alias2> => <table2>, -join_type => 'inner|left|right' },
2157 [], # nested JOIN (optional)
2158 { <table1.column1> => <table2.column2>, ... (more conditions) },
2160 # More of the above [ ] may follow for additional joins
2167 ON <table1.column1> = <table2.column2>
2168 <more joins may follow>
2170 An easy way to follow the examples below is to remember the following:
2172 Anything inside "[]" is a JOIN
2173 Anything inside "{}" is a condition for the enclosing JOIN
2175 The following examples utilize a "person" table in a family tree application.
2176 In order to express parent->child relationships, this table is self-joined:
2178 # Person->belongs_to('father' => 'Person');
2179 # Person->belongs_to('mother' => 'Person');
2181 C<from> can be used to nest joins. Here we return all children with a father,
2182 then search against all mothers of those children:
2184 $rs = $schema->resultset('Person')->search(
2187 alias => 'mother', # alias columns in accordance with "from"
2189 { mother => 'person' },
2192 { child => 'person' },
2194 { father => 'person' },
2195 { 'father.person_id' => 'child.father_id' }
2198 { 'mother.person_id' => 'child.mother_id' }
2205 # SELECT mother.* FROM person mother
2208 # JOIN person father
2209 # ON ( father.person_id = child.father_id )
2211 # ON ( mother.person_id = child.mother_id )
2213 The type of any join can be controlled manually. To search against only people
2214 with a father in the person table, we could explicitly use C<INNER JOIN>:
2216 $rs = $schema->resultset('Person')->search(
2219 alias => 'child', # alias columns in accordance with "from"
2221 { child => 'person' },
2223 { father => 'person', -join_type => 'inner' },
2224 { 'father.id' => 'child.father_id' }
2231 # SELECT child.* FROM person child
2232 # INNER JOIN person father ON child.father_id = father.id