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 result_source => $source,
102 result_class => $attrs->{result_class} || $source->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 L</ATTRIBUTES>. For more examples of using this function, see L<Searching|DBIx::Class::Manual::Cookbook/Searching>.
144 my $rs = $self->search_rs( @_ );
145 return (wantarray ? $rs->all : $rs);
152 =item Arguments: $cond, \%attrs?
154 =item Return Value: $resultset
158 This method does the same exact thing as search() except it will
159 always return a resultset, even in list context.
168 unless (@_) { # no search, effectively just a clone
169 $rows = $self->get_cache;
173 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
174 my $our_attrs = { %{$self->{attrs}} };
175 my $having = delete $our_attrs->{having};
176 my $where = delete $our_attrs->{where};
178 my $new_attrs = { %{$our_attrs}, %{$attrs} };
180 # merge new attrs into inherited
181 foreach my $key (qw/join prefetch/) {
182 next unless exists $attrs->{$key};
183 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
188 (@_ == 1 || ref $_[0] eq "HASH")
190 (ref $_[0] eq 'HASH')
192 (keys %{ $_[0] } > 0)
200 ? $self->throw_exception("Odd number of arguments to search")
207 if (defined $where) {
208 $new_attrs->{where} = (
209 defined $new_attrs->{where}
212 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
213 } $where, $new_attrs->{where}
220 $new_attrs->{where} = (
221 defined $new_attrs->{where}
224 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
225 } $cond, $new_attrs->{where}
231 if (defined $having) {
232 $new_attrs->{having} = (
233 defined $new_attrs->{having}
236 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
237 } $having, $new_attrs->{having}
243 my $rs = (ref $self)->new($self->result_source, $new_attrs);
245 $rs->set_cache($rows);
250 =head2 search_literal
254 =item Arguments: $sql_fragment, @bind_values
256 =item Return Value: $resultset (scalar context), @row_objs (list context)
260 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
261 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
263 Pass a literal chunk of SQL to be added to the conditional part of the
269 my ($self, $cond, @vals) = @_;
270 my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
271 $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ];
272 return $self->search(\$cond, $attrs);
279 =item Arguments: @values | \%cols, \%attrs?
281 =item Return Value: $row_object
285 Finds a row based on its primary key or unique constraint. For example, to find
286 a row by its primary key:
288 my $cd = $schema->resultset('CD')->find(5);
290 You can also find a row by a specific unique constraint using the C<key>
291 attribute. For example:
293 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
294 key => 'cd_artist_title'
297 Additionally, you can specify the columns explicitly by name:
299 my $cd = $schema->resultset('CD')->find(
301 artist => 'Massive Attack',
302 title => 'Mezzanine',
304 { key => 'cd_artist_title' }
307 If the C<key> is specified as C<primary>, it searches only on the primary key.
309 If no C<key> is specified, it searches on all unique constraints defined on the
310 source, including the primary key.
312 If your table does not have a primary key, you B<must> provide a value for the
313 C<key> attribute matching one of the unique constraints on the source.
315 See also L</find_or_create> and L</update_or_create>. For information on how to
316 declare unique constraints, see
317 L<DBIx::Class::ResultSource/add_unique_constraint>.
323 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
325 # Default to the primary key, but allow a specific key
326 my @cols = exists $attrs->{key}
327 ? $self->result_source->unique_constraint_columns($attrs->{key})
328 : $self->result_source->primary_columns;
329 $self->throw_exception(
330 "Can't find unless a primary key is defined or unique constraint is specified"
333 # Parse out a hashref from input
335 if (ref $_[0] eq 'HASH') {
336 $input_query = { %{$_[0]} };
338 elsif (@_ == @cols) {
340 @{$input_query}{@cols} = @_;
343 # Compatibility: Allow e.g. find(id => $value)
344 carp "Find by key => value deprecated; please use a hashref instead";
348 my (%related, $info);
350 foreach my $key (keys %$input_query) {
351 if (ref($input_query->{$key})
352 && ($info = $self->result_source->relationship_info($key))) {
353 my $rel_q = $self->result_source->resolve_condition(
354 $info->{cond}, delete $input_query->{$key}, $key
356 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
357 @related{keys %$rel_q} = values %$rel_q;
360 if (my @keys = keys %related) {
361 @{$input_query}{@keys} = values %related;
364 my @unique_queries = $self->_unique_queries($input_query, $attrs);
366 # Build the final query: Default to the disjunction of the unique queries,
367 # but allow the input query in case the ResultSet defines the query or the
368 # user is abusing find
369 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
370 my $query = @unique_queries
371 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
372 : $self->_add_alias($input_query, $alias);
376 my $rs = $self->search($query, $attrs);
377 return keys %{$rs->_resolved_attrs->{collapse}} ? $rs->next : $rs->single;
380 return keys %{$self->_resolved_attrs->{collapse}}
381 ? $self->search($query)->next
382 : $self->single($query);
388 # Add the specified alias to the specified query hash. A copy is made so the
389 # original query is not modified.
392 my ($self, $query, $alias) = @_;
394 my %aliased = %$query;
395 foreach my $col (grep { ! m/\./ } keys %aliased) {
396 $aliased{"$alias.$col"} = delete $aliased{$col};
404 # Build a list of queries which satisfy unique constraints.
406 sub _unique_queries {
407 my ($self, $query, $attrs) = @_;
409 my @constraint_names = exists $attrs->{key}
411 : $self->result_source->unique_constraint_names;
413 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
414 my $num_where = scalar keys %$where;
417 foreach my $name (@constraint_names) {
418 my @unique_cols = $self->result_source->unique_constraint_columns($name);
419 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
421 my $num_cols = scalar @unique_cols;
422 my $num_query = scalar keys %$unique_query;
424 my $total = $num_query + $num_where;
425 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
426 # The query is either unique on its own or is unique in combination with
427 # the existing where clause
428 push @unique_queries, $unique_query;
432 return @unique_queries;
435 # _build_unique_query
437 # Constrain the specified query hash based on the specified column names.
439 sub _build_unique_query {
440 my ($self, $query, $unique_cols) = @_;
443 map { $_ => $query->{$_} }
444 grep { exists $query->{$_} }
449 =head2 search_related
453 =item Arguments: $rel, $cond, \%attrs?
455 =item Return Value: $new_resultset
459 $new_rs = $cd_rs->search_related('artist', {
463 Searches the specified relationship, optionally specifying a condition and
464 attributes for matching records. See L</ATTRIBUTES> for more information.
469 return shift->related_resultset(shift)->search(@_);
476 =item Arguments: none
478 =item Return Value: $cursor
482 Returns a storage-driven cursor to the given resultset. See
483 L<DBIx::Class::Cursor> for more information.
490 my $attrs = { %{$self->_resolved_attrs} };
491 return $self->{cursor}
492 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
493 $attrs->{where},$attrs);
500 =item Arguments: $cond?
502 =item Return Value: $row_object?
506 my $cd = $schema->resultset('CD')->single({ year => 2001 });
508 Inflates the first result without creating a cursor if the resultset has
509 any records in it; if not returns nothing. Used by L</find> as an optimisation.
511 Can optionally take an additional condition *only* - this is a fast-code-path
512 method; if you need to add extra joins or similar call ->search and then
513 ->single without a condition on the $rs returned from that.
518 my ($self, $where) = @_;
519 my $attrs = { %{$self->_resolved_attrs} };
521 if (defined $attrs->{where}) {
524 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
525 $where, delete $attrs->{where} ]
528 $attrs->{where} = $where;
532 # XXX: Disabled since it doesn't infer uniqueness in all cases
533 # unless ($self->_is_unique_query($attrs->{where})) {
534 # carp "Query not guaranteed to return a single row"
535 # . "; please declare your unique constraints or use search instead";
538 my @data = $self->result_source->storage->select_single(
539 $attrs->{from}, $attrs->{select},
540 $attrs->{where}, $attrs
543 return (@data ? ($self->_construct_object(@data))[0] : ());
548 # Try to determine if the specified query is guaranteed to be unique, based on
549 # the declared unique constraints.
551 sub _is_unique_query {
552 my ($self, $query) = @_;
554 my $collapsed = $self->_collapse_query($query);
555 my $alias = $self->{attrs}{alias};
557 foreach my $name ($self->result_source->unique_constraint_names) {
558 my @unique_cols = map {
560 } $self->result_source->unique_constraint_columns($name);
562 # Count the values for each unique column
563 my %seen = map { $_ => 0 } @unique_cols;
565 foreach my $key (keys %$collapsed) {
566 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
567 next unless exists $seen{$aliased}; # Additional constraints are okay
568 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
571 # If we get 0 or more than 1 value for a column, it's not necessarily unique
572 return 1 unless grep { $_ != 1 } values %seen;
580 # Recursively collapse the query, accumulating values for each column.
582 sub _collapse_query {
583 my ($self, $query, $collapsed) = @_;
587 if (ref $query eq 'ARRAY') {
588 foreach my $subquery (@$query) {
589 next unless ref $subquery; # -or
590 # warn "ARRAY: " . Dumper $subquery;
591 $collapsed = $self->_collapse_query($subquery, $collapsed);
594 elsif (ref $query eq 'HASH') {
595 if (keys %$query and (keys %$query)[0] eq '-and') {
596 foreach my $subquery (@{$query->{-and}}) {
597 # warn "HASH: " . Dumper $subquery;
598 $collapsed = $self->_collapse_query($subquery, $collapsed);
602 # warn "LEAF: " . Dumper $query;
603 foreach my $col (keys %$query) {
604 my $value = $query->{$col};
605 $collapsed->{$col}{$value}++;
617 =item Arguments: $cond?
619 =item Return Value: $resultsetcolumn
623 my $max_length = $rs->get_column('length')->max;
625 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
630 my ($self, $column) = @_;
631 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
639 =item Arguments: $cond, \%attrs?
641 =item Return Value: $resultset (scalar context), @row_objs (list context)
645 # WHERE title LIKE '%blue%'
646 $cd_rs = $rs->search_like({ title => '%blue%'});
648 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
649 that this is simply a convenience method. You most likely want to use
650 L</search> with specific operators.
652 For more information, see L<DBIx::Class::Manual::Cookbook>.
658 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
659 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
660 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
661 return $class->search($query, { %$attrs });
668 =item Arguments: $first, $last
670 =item Return Value: $resultset (scalar context), @row_objs (list context)
674 Returns a resultset or object list representing a subset of elements from the
675 resultset slice is called on. Indexes are from 0, i.e., to get the first
678 my ($one, $two, $three) = $rs->slice(0, 2);
683 my ($self, $min, $max) = @_;
684 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
685 $attrs->{offset} = $self->{attrs}{offset} || 0;
686 $attrs->{offset} += $min;
687 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
688 return $self->search(undef(), $attrs);
689 #my $slice = (ref $self)->new($self->result_source, $attrs);
690 #return (wantarray ? $slice->all : $slice);
697 =item Arguments: none
699 =item Return Value: $result?
703 Returns the next element in the resultset (C<undef> is there is none).
705 Can be used to efficiently iterate over records in the resultset:
707 my $rs = $schema->resultset('CD')->search;
708 while (my $cd = $rs->next) {
712 Note that you need to store the resultset object, and call C<next> on it.
713 Calling C<< resultset('Table')->next >> repeatedly will always return the
714 first record from the resultset.
720 if (my $cache = $self->get_cache) {
721 $self->{all_cache_position} ||= 0;
722 return $cache->[$self->{all_cache_position}++];
724 if ($self->{attrs}{cache}) {
725 $self->{all_cache_position} = 1;
726 return ($self->all)[0];
728 if ($self->{stashed_objects}) {
729 my $obj = shift(@{$self->{stashed_objects}});
730 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
734 exists $self->{stashed_row}
735 ? @{delete $self->{stashed_row}}
736 : $self->cursor->next
738 return unless (@row);
739 my ($row, @more) = $self->_construct_object(@row);
740 $self->{stashed_objects} = \@more if @more;
744 sub _construct_object {
745 my ($self, @row) = @_;
746 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
747 my @new = $self->result_class->inflate_result($self->result_source, @$info);
748 @new = $self->{_attrs}{record_filter}->(@new)
749 if exists $self->{_attrs}{record_filter};
753 sub _collapse_result {
754 my ($self, $as_proto, $row) = @_;
758 # 'foo' => [ undef, 'foo' ]
759 # 'foo.bar' => [ 'foo', 'bar' ]
760 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
762 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
764 my %collapse = %{$self->{_attrs}{collapse}||{}};
768 # if we're doing collapsing (has_many prefetch) we need to grab records
769 # until the PK changes, so fill @pri_index. if not, we leave it empty so
770 # we know we don't have to bother.
772 # the reason for not using the collapse stuff directly is because if you
773 # had for e.g. two artists in a row with no cds, the collapse info for
774 # both would be NULL (undef) so you'd lose the second artist
776 # store just the index so we can check the array positions from the row
777 # without having to contruct the full hash
779 if (keys %collapse) {
780 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
781 foreach my $i (0 .. $#construct_as) {
782 if (delete $pri{$construct_as[$i]}) {
783 push(@pri_index, $i);
785 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
789 # no need to do an if, it'll be empty if @pri_index is empty anyway
791 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
795 do { # no need to check anything at the front, we always want the first row
797 foreach my $this_as (@construct_as) {
798 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
801 } until ( # no pri_index => no collapse => drop straight out
804 do { # get another row, stash it, drop out if different PK
806 @copy = $self->cursor->next;
807 $self->{stashed_row} = \@copy;
809 # last thing in do block, counts as true if anything doesn't match
811 # check xor defined first for NULL vs. NOT NULL then if one is
812 # defined the other must be so check string equality
815 (defined $pri_vals{$_} ^ defined $copy[$_])
816 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
821 # THIS BIT STILL NEEDS TO DO THE COLLAPSE
823 my $alias = $self->{attrs}{alias};
824 my $info = [ {}, {} ];
825 foreach my $key (keys %const) {
826 if (length $key && $key ne $alias) {
828 my @parts = split(/\./, $key);
829 foreach my $p (@parts) {
830 $target = $target->[1]->{$p} ||= [];
832 $target->[0] = $const{$key};
834 $info->[0] = $const{$key};
845 =item Arguments: $result_source?
847 =item Return Value: $result_source
851 An accessor for the primary ResultSource object from which this ResultSet
858 =item Arguments: $result_class?
860 =item Return Value: $result_class
864 An accessor for the class to use when creating row objects. Defaults to
865 C<< result_source->result_class >> - which in most cases is the name of the
866 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
875 =item Arguments: $cond, \%attrs??
877 =item Return Value: $count
881 Performs an SQL C<COUNT> with the same query as the resultset was built
882 with to find the number of elements. If passed arguments, does a search
883 on the resultset and counts the results of that.
885 Note: When using C<count> with C<group_by>, L<DBIX::Class> emulates C<GROUP BY>
886 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
887 not support C<DISTINCT> with multiple columns. If you are using such a
888 database, you should only use columns from the main table in your C<group_by>
895 return $self->search(@_)->count if @_ and defined $_[0];
896 return scalar @{ $self->get_cache } if $self->get_cache;
897 my $count = $self->_count;
898 return 0 unless $count;
900 $count -= $self->{attrs}{offset} if $self->{attrs}{offset};
901 $count = $self->{attrs}{rows} if
902 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
906 sub _count { # Separated out so pager can get the full count
908 my $select = { count => '*' };
910 my $attrs = { %{$self->_resolved_attrs} };
911 if (my $group_by = delete $attrs->{group_by}) {
912 delete $attrs->{having};
913 my @distinct = (ref $group_by ? @$group_by : ($group_by));
914 # todo: try CONCAT for multi-column pk
915 my @pk = $self->result_source->primary_columns;
917 my $alias = $attrs->{alias};
918 foreach my $column (@distinct) {
919 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
920 @distinct = ($column);
926 $select = { count => { distinct => \@distinct } };
929 $attrs->{select} = $select;
930 $attrs->{as} = [qw/count/];
932 # offset, order by and page are not needed to count. record_filter is cdbi
933 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
935 my $tmp_rs = (ref $self)->new($self->_source_handle, $attrs);
936 my ($count) = $tmp_rs->cursor->next;
944 =item Arguments: $sql_fragment, @bind_values
946 =item Return Value: $count
950 Counts the results in a literal query. Equivalent to calling L</search_literal>
951 with the passed arguments, then L</count>.
955 sub count_literal { shift->search_literal(@_)->count; }
961 =item Arguments: none
963 =item Return Value: @objects
967 Returns all elements in the resultset. Called implicitly if the resultset
968 is returned in list context.
974 return @{ $self->get_cache } if $self->get_cache;
978 # TODO: don't call resolve here
979 if (keys %{$self->_resolved_attrs->{collapse}}) {
980 # if ($self->{attrs}{prefetch}) {
981 # Using $self->cursor->all is really just an optimisation.
982 # If we're collapsing has_many prefetches it probably makes
983 # very little difference, and this is cleaner than hacking
984 # _construct_object to survive the approach
985 my @row = $self->cursor->next;
987 push(@obj, $self->_construct_object(@row));
988 @row = (exists $self->{stashed_row}
989 ? @{delete $self->{stashed_row}}
990 : $self->cursor->next);
993 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
996 $self->set_cache(\@obj) if $self->{attrs}{cache};
1004 =item Arguments: none
1006 =item Return Value: $self
1010 Resets the resultset's cursor, so you can iterate through the elements again.
1016 delete $self->{_attrs} if exists $self->{_attrs};
1017 $self->{all_cache_position} = 0;
1018 $self->cursor->reset;
1026 =item Arguments: none
1028 =item Return Value: $object?
1032 Resets the resultset and returns an object for the first result (if the
1033 resultset returns anything).
1038 return $_[0]->reset->next;
1041 # _cond_for_update_delete
1043 # update/delete require the condition to be modified to handle
1044 # the differing SQL syntax available. This transforms the $self->{cond}
1045 # appropriately, returning the new condition.
1047 sub _cond_for_update_delete {
1048 my ($self, $full_cond) = @_;
1051 $full_cond ||= $self->{cond};
1052 # No-op. No condition, we're updating/deleting everything
1053 return $cond unless ref $full_cond;
1055 if (ref $full_cond eq 'ARRAY') {
1059 foreach my $key (keys %{$_}) {
1061 $hash{$1} = $_->{$key};
1067 elsif (ref $full_cond eq 'HASH') {
1068 if ((keys %{$full_cond})[0] eq '-and') {
1071 my @cond = @{$full_cond->{-and}};
1072 for (my $i = 0; $i < @cond; $i++) {
1073 my $entry = $cond[$i];
1076 if (ref $entry eq 'HASH') {
1077 $hash = $self->_cond_for_update_delete($entry);
1080 $entry =~ /([^.]+)$/;
1081 $hash->{$1} = $cond[++$i];
1084 push @{$cond->{-and}}, $hash;
1088 foreach my $key (keys %{$full_cond}) {
1090 $cond->{$1} = $full_cond->{$key};
1095 $self->throw_exception(
1096 "Can't update/delete on resultset with condition unless hash or array"
1108 =item Arguments: \%values
1110 =item Return Value: $storage_rv
1114 Sets the specified columns in the resultset to the supplied values in a
1115 single query. Return value will be true if the update succeeded or false
1116 if no records were updated; exact type of success value is storage-dependent.
1121 my ($self, $values) = @_;
1122 $self->throw_exception("Values for update must be a hash")
1123 unless ref $values eq 'HASH';
1125 my $cond = $self->_cond_for_update_delete;
1127 return $self->result_source->storage->update(
1128 $self->result_source, $values, $cond
1136 =item Arguments: \%values
1138 =item Return Value: 1
1142 Fetches all objects and updates them one at a time. Note that C<update_all>
1143 will run DBIC cascade triggers, while L</update> will not.
1148 my ($self, $values) = @_;
1149 $self->throw_exception("Values for update must be a hash")
1150 unless ref $values eq 'HASH';
1151 foreach my $obj ($self->all) {
1152 $obj->set_columns($values)->update;
1161 =item Arguments: none
1163 =item Return Value: 1
1167 Deletes the contents of the resultset from its result source. Note that this
1168 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1169 to run. See also L<DBIx::Class::Row/delete>.
1176 my $cond = $self->_cond_for_update_delete;
1178 $self->result_source->storage->delete($self->result_source, $cond);
1186 =item Arguments: none
1188 =item Return Value: 1
1192 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1193 will run DBIC cascade triggers, while L</delete> will not.
1199 $_->delete for $self->all;
1207 =item Arguments: none
1209 =item Return Value: $pager
1213 Return Value a L<Data::Page> object for the current resultset. Only makes
1214 sense for queries with a C<page> attribute.
1220 my $attrs = $self->{attrs};
1221 $self->throw_exception("Can't create pager for non-paged rs")
1222 unless $self->{attrs}{page};
1223 $attrs->{rows} ||= 10;
1224 return $self->{pager} ||= Data::Page->new(
1225 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1232 =item Arguments: $page_number
1234 =item Return Value: $rs
1238 Returns a resultset for the $page_number page of the resultset on which page
1239 is called, where each page contains a number of rows equal to the 'rows'
1240 attribute set on the resultset (10 by default).
1245 my ($self, $page) = @_;
1246 return (ref $self)->new($self->_source_handle, { %{$self->{attrs}}, page => $page });
1253 =item Arguments: \%vals
1255 =item Return Value: $object
1259 Creates an object in the resultset's result class and returns it.
1264 my ($self, $values) = @_;
1265 $self->throw_exception( "new_result needs a hash" )
1266 unless (ref $values eq 'HASH');
1267 $self->throw_exception(
1268 "Can't abstract implicit construct, condition not a hash"
1269 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1271 my $alias = $self->{attrs}{alias};
1272 my $collapsed_cond = $self->{cond} ? $self->_collapse_cond($self->{cond}) : {};
1274 %{ $self->_remove_alias($values, $alias) },
1275 %{ $self->_remove_alias($collapsed_cond, $alias) },
1278 return $self->result_class->new(\%new,$self->_source_handle);
1283 # Recursively collapse the condition.
1285 sub _collapse_cond {
1286 my ($self, $cond, $collapsed) = @_;
1290 if (ref $cond eq 'ARRAY') {
1291 foreach my $subcond (@$cond) {
1292 next unless ref $subcond; # -or
1293 # warn "ARRAY: " . Dumper $subcond;
1294 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1297 elsif (ref $cond eq 'HASH') {
1298 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1299 foreach my $subcond (@{$cond->{-and}}) {
1300 # warn "HASH: " . Dumper $subcond;
1301 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1305 # warn "LEAF: " . Dumper $cond;
1306 foreach my $col (keys %$cond) {
1307 my $value = $cond->{$col};
1308 $collapsed->{$col} = $value;
1318 # Remove the specified alias from the specified query hash. A copy is made so
1319 # the original query is not modified.
1322 my ($self, $query, $alias) = @_;
1324 my %orig = %{ $query || {} };
1327 foreach my $key (keys %orig) {
1329 $unaliased{$key} = $orig{$key};
1332 $unaliased{$1} = $orig{$key}
1333 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1343 =item Arguments: \%vals, \%attrs?
1345 =item Return Value: $object
1349 Find an existing record from this resultset. If none exists, instantiate a new
1350 result object and return it. The object will not be saved into your storage
1351 until you call L<DBIx::Class::Row/insert> on it.
1353 If you want objects to be saved immediately, use L</find_or_create> instead.
1359 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1360 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1361 my $exists = $self->find($hash, $attrs);
1362 return defined $exists ? $exists : $self->new_result($hash);
1369 =item Arguments: \%vals
1371 =item Return Value: $object
1375 Inserts a record into the resultset and returns the object representing it.
1377 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1382 my ($self, $attrs) = @_;
1383 $self->throw_exception( "create needs a hashref" )
1384 unless ref $attrs eq 'HASH';
1385 return $self->new_result($attrs)->insert;
1388 =head2 find_or_create
1392 =item Arguments: \%vals, \%attrs?
1394 =item Return Value: $object
1398 $class->find_or_create({ key => $val, ... });
1400 Tries to find a record based on its primary key or unique constraint; if none
1401 is found, creates one and returns that instead.
1403 my $cd = $schema->resultset('CD')->find_or_create({
1405 artist => 'Massive Attack',
1406 title => 'Mezzanine',
1410 Also takes an optional C<key> attribute, to search by a specific key or unique
1411 constraint. For example:
1413 my $cd = $schema->resultset('CD')->find_or_create(
1415 artist => 'Massive Attack',
1416 title => 'Mezzanine',
1418 { key => 'cd_artist_title' }
1421 See also L</find> and L</update_or_create>. For information on how to declare
1422 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1426 sub find_or_create {
1428 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1429 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1430 my $exists = $self->find($hash, $attrs);
1431 return defined $exists ? $exists : $self->create($hash);
1434 =head2 update_or_create
1438 =item Arguments: \%col_values, { key => $unique_constraint }?
1440 =item Return Value: $object
1444 $class->update_or_create({ col => $val, ... });
1446 First, searches for an existing row matching one of the unique constraints
1447 (including the primary key) on the source of this resultset. If a row is
1448 found, updates it with the other given column values. Otherwise, creates a new
1451 Takes an optional C<key> attribute to search on a specific unique constraint.
1454 # In your application
1455 my $cd = $schema->resultset('CD')->update_or_create(
1457 artist => 'Massive Attack',
1458 title => 'Mezzanine',
1461 { key => 'cd_artist_title' }
1464 If no C<key> is specified, it searches on all unique constraints defined on the
1465 source, including the primary key.
1467 If the C<key> is specified as C<primary>, it searches only on the primary key.
1469 See also L</find> and L</find_or_create>. For information on how to declare
1470 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1474 sub update_or_create {
1476 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1477 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
1479 my $row = $self->find($cond, $attrs);
1481 $row->update($cond);
1485 return $self->create($cond);
1492 =item Arguments: none
1494 =item Return Value: \@cache_objects?
1498 Gets the contents of the cache for the resultset, if the cache is set.
1510 =item Arguments: \@cache_objects
1512 =item Return Value: \@cache_objects
1516 Sets the contents of the cache for the resultset. Expects an arrayref
1517 of objects of the same class as those produced by the resultset. Note that
1518 if the cache is set the resultset will return the cached objects rather
1519 than re-querying the database even if the cache attr is not set.
1524 my ( $self, $data ) = @_;
1525 $self->throw_exception("set_cache requires an arrayref")
1526 if defined($data) && (ref $data ne 'ARRAY');
1527 $self->{all_cache} = $data;
1534 =item Arguments: none
1536 =item Return Value: []
1540 Clears the cache for the resultset.
1545 shift->set_cache(undef);
1548 =head2 related_resultset
1552 =item Arguments: $relationship_name
1554 =item Return Value: $resultset
1558 Returns a related resultset for the supplied relationship name.
1560 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
1564 sub related_resultset {
1565 my ($self, $rel) = @_;
1567 $self->{related_resultsets} ||= {};
1568 return $self->{related_resultsets}{$rel} ||= do {
1569 my $rel_obj = $self->result_source->relationship_info($rel);
1571 $self->throw_exception(
1572 "search_related: result source '" . $self->_source_handle->source_moniker .
1573 "' has no such relationship $rel")
1576 my ($from,$seen) = $self->_resolve_from($rel);
1578 my $join_count = $seen->{$rel};
1579 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
1581 $self->_source_handle->schema->resultset($rel_obj->{class})->search_rs(
1583 %{$self->{attrs}||{}},
1589 where => $self->{cond},
1597 my ($self, $extra_join) = @_;
1598 my $source = $self->result_source;
1599 my $attrs = $self->{attrs};
1601 my $from = $attrs->{from}
1602 || [ { $attrs->{alias} => $source->from } ];
1604 my $seen = { %{$attrs->{seen_join}||{}} };
1606 my $join = ($attrs->{join}
1607 ? [ $attrs->{join}, $extra_join ]
1611 ($join ? $source->resolve_join($join, $attrs->{alias}, $seen) : ()),
1614 return ($from,$seen);
1617 sub _resolved_attrs {
1619 return $self->{_attrs} if $self->{_attrs};
1621 my $attrs = { %{$self->{attrs}||{}} };
1622 my $source = $self->result_source;
1623 my $alias = $attrs->{alias};
1625 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
1626 if ($attrs->{columns}) {
1627 delete $attrs->{as};
1628 } elsif (!$attrs->{select}) {
1629 $attrs->{columns} = [ $source->columns ];
1634 ? (ref $attrs->{select} eq 'ARRAY'
1635 ? [ @{$attrs->{select}} ]
1636 : [ $attrs->{select} ])
1637 : [ map { m/\./ ? $_ : "${alias}.$_" } @{delete $attrs->{columns}} ]
1641 ? (ref $attrs->{as} eq 'ARRAY'
1642 ? [ @{$attrs->{as}} ]
1644 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{$attrs->{select}} ]
1648 if ($adds = delete $attrs->{include_columns}) {
1649 $adds = [$adds] unless ref $adds eq 'ARRAY';
1650 push(@{$attrs->{select}}, @$adds);
1651 push(@{$attrs->{as}}, map { m/([^.]+)$/; $1 } @$adds);
1653 if ($adds = delete $attrs->{'+select'}) {
1654 $adds = [$adds] unless ref $adds eq 'ARRAY';
1655 push(@{$attrs->{select}},
1656 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds);
1658 if (my $adds = delete $attrs->{'+as'}) {
1659 $adds = [$adds] unless ref $adds eq 'ARRAY';
1660 push(@{$attrs->{as}}, @$adds);
1663 $attrs->{from} ||= [ { 'me' => $source->from } ];
1665 if (exists $attrs->{join} || exists $attrs->{prefetch}) {
1666 my $join = delete $attrs->{join} || {};
1668 if (defined $attrs->{prefetch}) {
1669 $join = $self->_merge_attr(
1670 $join, $attrs->{prefetch}
1674 $attrs->{from} = # have to copy here to avoid corrupting the original
1677 $source->resolve_join($join, $alias, { %{$attrs->{seen_join}||{}} })
1681 $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
1682 if ($attrs->{order_by}) {
1683 $attrs->{order_by} = (ref($attrs->{order_by}) eq 'ARRAY'
1684 ? [ @{$attrs->{order_by}} ]
1685 : [ $attrs->{order_by} ]);
1687 $attrs->{order_by} = [];
1690 my $collapse = $attrs->{collapse} || {};
1691 if (my $prefetch = delete $attrs->{prefetch}) {
1692 $prefetch = $self->_merge_attr({}, $prefetch);
1694 my $seen = $attrs->{seen_join} || {};
1695 foreach my $p (ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch)) {
1696 # bring joins back to level of current class
1697 my @prefetch = $source->resolve_prefetch(
1698 $p, $alias, $seen, \@pre_order, $collapse
1700 push(@{$attrs->{select}}, map { $_->[0] } @prefetch);
1701 push(@{$attrs->{as}}, map { $_->[1] } @prefetch);
1703 push(@{$attrs->{order_by}}, @pre_order);
1705 $attrs->{collapse} = $collapse;
1707 return $self->{_attrs} = $attrs;
1711 my ($self, $a, $b) = @_;
1712 return $b unless defined($a);
1713 return $a unless defined($b);
1715 if (ref $b eq 'HASH' && ref $a eq 'HASH') {
1716 foreach my $key (keys %{$b}) {
1717 if (exists $a->{$key}) {
1718 $a->{$key} = $self->_merge_attr($a->{$key}, $b->{$key});
1720 $a->{$key} = $b->{$key};
1725 $a = [$a] unless ref $a eq 'ARRAY';
1726 $b = [$b] unless ref $b eq 'ARRAY';
1730 foreach my $x ($a, $b) {
1731 foreach my $element (@{$x}) {
1732 if (ref $element eq 'HASH') {
1733 $hash = $self->_merge_attr($hash, $element);
1734 } elsif (ref $element eq 'ARRAY') {
1735 push(@array, @{$element});
1737 push(@array, $element) unless $b == $x
1738 && grep { $_ eq $element } @array;
1743 @array = grep { !exists $hash->{$_} } @array;
1745 return keys %{$hash}
1758 $self->_source_handle($_[0]->handle);
1760 $self->_source_handle->resolve;
1764 =head2 throw_exception
1766 See L<DBIx::Class::Schema/throw_exception> for details.
1770 sub throw_exception {
1772 $self->_source_handle->schema->throw_exception(@_);
1775 # XXX: FIXME: Attributes docs need clearing up
1779 The resultset takes various attributes that modify its behavior. Here's an
1786 =item Value: ($order_by | \@order_by)
1790 Which column(s) to order the results by. This is currently passed
1791 through directly to SQL, so you can give e.g. C<year DESC> for a
1792 descending order on the column `year'.
1794 Please note that if you have C<quote_char> enabled (see
1795 L<DBIx::Class::Storage::DBI/connect_info>) you will need to do C<\'year DESC' > to
1796 specify an order. (The scalar ref causes it to be passed as raw sql to the DB,
1797 so you will need to manually quote things as appropriate.)
1803 =item Value: \@columns
1807 Shortcut to request a particular set of columns to be retrieved. Adds
1808 C<me.> onto the start of any column without a C<.> in it and sets C<select>
1809 from that, then auto-populates C<as> from C<select> as normal. (You may also
1810 use the C<cols> attribute, as in earlier versions of DBIC.)
1812 =head2 include_columns
1816 =item Value: \@columns
1820 Shortcut to include additional columns in the returned results - for example
1822 $schema->resultset('CD')->search(undef, {
1823 include_columns => ['artist.name'],
1827 would return all CDs and include a 'name' column to the information
1828 passed to object inflation
1834 =item Value: \@select_columns
1838 Indicates which columns should be selected from the storage. You can use
1839 column names, or in the case of RDBMS back ends, function or stored procedure
1842 $rs = $schema->resultset('Employee')->search(undef, {
1845 { count => 'employeeid' },
1850 When you use function/stored procedure names and do not supply an C<as>
1851 attribute, the column names returned are storage-dependent. E.g. MySQL would
1852 return a column named C<count(employeeid)> in the above example.
1858 Indicates additional columns to be selected from storage. Works the same as
1859 L<select> but adds columns to the selection.
1867 Indicates additional column names for those added via L<+select>.
1875 =item Value: \@inflation_names
1879 Indicates column names for object inflation. This is used in conjunction with
1880 C<select>, usually when C<select> contains one or more function or stored
1883 $rs = $schema->resultset('Employee')->search(undef, {
1886 { count => 'employeeid' }
1888 as => ['name', 'employee_count'],
1891 my $employee = $rs->first(); # get the first Employee
1893 If the object against which the search is performed already has an accessor
1894 matching a column name specified in C<as>, the value can be retrieved using
1895 the accessor as normal:
1897 my $name = $employee->name();
1899 If on the other hand an accessor does not exist in the object, you need to
1900 use C<get_column> instead:
1902 my $employee_count = $employee->get_column('employee_count');
1904 You can create your own accessors if required - see
1905 L<DBIx::Class::Manual::Cookbook> for details.
1907 Please note: This will NOT insert an C<AS employee_count> into the SQL
1908 statement produced, it is used for internal access only. Thus
1909 attempting to use the accessor in an C<order_by> clause or similar
1910 will fail miserably.
1912 To get around this limitation, you can supply literal SQL to your
1913 C<select> attibute that contains the C<AS alias> text, eg:
1915 select => [\'myfield AS alias']
1921 =item Value: ($rel_name | \@rel_names | \%rel_names)
1925 Contains a list of relationships that should be joined for this query. For
1928 # Get CDs by Nine Inch Nails
1929 my $rs = $schema->resultset('CD')->search(
1930 { 'artist.name' => 'Nine Inch Nails' },
1931 { join => 'artist' }
1934 Can also contain a hash reference to refer to the other relation's relations.
1937 package MyApp::Schema::Track;
1938 use base qw/DBIx::Class/;
1939 __PACKAGE__->table('track');
1940 __PACKAGE__->add_columns(qw/trackid cd position title/);
1941 __PACKAGE__->set_primary_key('trackid');
1942 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
1945 # In your application
1946 my $rs = $schema->resultset('Artist')->search(
1947 { 'track.title' => 'Teardrop' },
1949 join => { cd => 'track' },
1950 order_by => 'artist.name',
1954 You need to use the relationship (not the table) name in conditions,
1955 because they are aliased as such. The current table is aliased as "me", so
1956 you need to use me.column_name in order to avoid ambiguity. For example:
1958 # Get CDs from 1984 with a 'Foo' track
1959 my $rs = $schema->resultset('CD')->search(
1962 'tracks.name' => 'Foo'
1964 { join => 'tracks' }
1967 If the same join is supplied twice, it will be aliased to <rel>_2 (and
1968 similarly for a third time). For e.g.
1970 my $rs = $schema->resultset('Artist')->search({
1971 'cds.title' => 'Down to Earth',
1972 'cds_2.title' => 'Popular',
1974 join => [ qw/cds cds/ ],
1977 will return a set of all artists that have both a cd with title 'Down
1978 to Earth' and a cd with title 'Popular'.
1980 If you want to fetch related objects from other tables as well, see C<prefetch>
1987 =item Value: ($rel_name | \@rel_names | \%rel_names)
1991 Contains one or more relationships that should be fetched along with the main
1992 query (when they are accessed afterwards they will have already been
1993 "prefetched"). This is useful for when you know you will need the related
1994 objects, because it saves at least one query:
1996 my $rs = $schema->resultset('Tag')->search(
2005 The initial search results in SQL like the following:
2007 SELECT tag.*, cd.*, artist.* FROM tag
2008 JOIN cd ON tag.cd = cd.cdid
2009 JOIN artist ON cd.artist = artist.artistid
2011 L<DBIx::Class> has no need to go back to the database when we access the
2012 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2015 Simple prefetches will be joined automatically, so there is no need
2016 for a C<join> attribute in the above search. If you're prefetching to
2017 depth (e.g. { cd => { artist => 'label' } or similar), you'll need to
2018 specify the join as well.
2020 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2021 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2022 with an accessor type of 'single' or 'filter').
2032 Makes the resultset paged and specifies the page to retrieve. Effectively
2033 identical to creating a non-pages resultset and then calling ->page($page)
2036 If L<rows> attribute is not specified it defualts to 10 rows per page.
2046 Specifes the maximum number of rows for direct retrieval or the number of
2047 rows per page if the page attribute or method is used.
2053 =item Value: $offset
2057 Specifies the (zero-based) row number for the first row to be returned, or the
2058 of the first row of the first page if paging is used.
2064 =item Value: \@columns
2068 A arrayref of columns to group by. Can include columns of joined tables.
2070 group_by => [qw/ column1 column2 ... /]
2076 =item Value: $condition
2080 HAVING is a select statement attribute that is applied between GROUP BY and
2081 ORDER BY. It is applied to the after the grouping calculations have been
2084 having => { 'count(employee)' => { '>=', 100 } }
2090 =item Value: (0 | 1)
2094 Set to 1 to group by all columns.
2100 Adds to the WHERE clause.
2102 # only return rows WHERE deleted IS NULL for all searches
2103 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2105 Can be overridden by passing C<{ where => undef }> as an attribute
2112 Set to 1 to cache search results. This prevents extra SQL queries if you
2113 revisit rows in your ResultSet:
2115 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2117 while( my $artist = $resultset->next ) {
2121 $rs->first; # without cache, this would issue a query
2123 By default, searches are not cached.
2125 For more examples of using these attributes, see
2126 L<DBIx::Class::Manual::Cookbook>.
2132 =item Value: \@from_clause
2136 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
2137 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
2140 NOTE: Use this on your own risk. This allows you to shoot off your foot!
2142 C<join> will usually do what you need and it is strongly recommended that you
2143 avoid using C<from> unless you cannot achieve the desired result using C<join>.
2144 And we really do mean "cannot", not just tried and failed. Attempting to use
2145 this because you're having problems with C<join> is like trying to use x86
2146 ASM because you've got a syntax error in your C. Trust us on this.
2148 Now, if you're still really, really sure you need to use this (and if you're
2149 not 100% sure, ask the mailing list first), here's an explanation of how this
2152 The syntax is as follows -
2155 { <alias1> => <table1> },
2157 { <alias2> => <table2>, -join_type => 'inner|left|right' },
2158 [], # nested JOIN (optional)
2159 { <table1.column1> => <table2.column2>, ... (more conditions) },
2161 # More of the above [ ] may follow for additional joins
2168 ON <table1.column1> = <table2.column2>
2169 <more joins may follow>
2171 An easy way to follow the examples below is to remember the following:
2173 Anything inside "[]" is a JOIN
2174 Anything inside "{}" is a condition for the enclosing JOIN
2176 The following examples utilize a "person" table in a family tree application.
2177 In order to express parent->child relationships, this table is self-joined:
2179 # Person->belongs_to('father' => 'Person');
2180 # Person->belongs_to('mother' => 'Person');
2182 C<from> can be used to nest joins. Here we return all children with a father,
2183 then search against all mothers of those children:
2185 $rs = $schema->resultset('Person')->search(
2188 alias => 'mother', # alias columns in accordance with "from"
2190 { mother => 'person' },
2193 { child => 'person' },
2195 { father => 'person' },
2196 { 'father.person_id' => 'child.father_id' }
2199 { 'mother.person_id' => 'child.mother_id' }
2206 # SELECT mother.* FROM person mother
2209 # JOIN person father
2210 # ON ( father.person_id = child.father_id )
2212 # ON ( mother.person_id = child.mother_id )
2214 The type of any join can be controlled manually. To search against only people
2215 with a father in the person table, we could explicitly use C<INNER JOIN>:
2217 $rs = $schema->resultset('Person')->search(
2220 alias => 'child', # alias columns in accordance with "from"
2222 { child => 'person' },
2224 { father => 'person', -join_type => 'inner' },
2225 { 'father.id' => 'child.father_id' }
2232 # SELECT child.* FROM person child
2233 # INNER JOIN person father ON child.father_id = father.id