1 package DBIx::Class::ResultSet;
9 use Carp::Clan qw/^DBIx::Class/;
12 use DBIx::Class::ResultSetColumn;
13 use DBIx::Class::ResultSourceHandle;
16 use base qw/DBIx::Class/;
18 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
22 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
26 my $users_rs = $schema->resultset('User');
27 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
28 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
32 A ResultSet is an object which stores a set of conditions representing
33 a query. It is the backbone of DBIx::Class (i.e. the really
34 important/useful bit).
36 No SQL is executed on the database when a ResultSet is created, it
37 just stores all the conditions needed to create the query.
39 A basic ResultSet representing the data of an entire table is returned
40 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
41 L<Source|DBIx::Class::Manual::Glossary/Source> name.
43 my $users_rs = $schema->resultset('User');
45 A new ResultSet is returned from calling L</search> on an existing
46 ResultSet. The new one will contain all the conditions of the
47 original, plus any new conditions added in the C<search> call.
49 A ResultSet is also an iterator. L</next> is used to return all the
50 L<DBIx::Class::Row>s the ResultSet represents.
52 The query that the ResultSet represents is B<only> executed against
53 the database when these methods are called:
73 =head2 Chaining resultsets
75 Let's say you've got a query that needs to be run to return some data
76 to the user. But, you have an authorization system in place that
77 prevents certain users from seeing certain information. So, you want
78 to construct the basic query in one method, but add constraints to it in
83 my $request = $self->get_request; # Get a request object somehow.
84 my $schema = $self->get_schema; # Get the DBIC schema object somehow.
86 my $cd_rs = $schema->resultset('CD')->search({
87 title => $request->param('title'),
88 year => $request->param('year'),
91 $self->apply_security_policy( $cd_rs );
96 sub apply_security_policy {
105 =head2 Multiple queries
107 Since a resultset just defines a query, you can do all sorts of
108 things with it with the same object.
110 # Don't hit the DB yet.
111 my $cd_rs = $schema->resultset('CD')->search({
112 title => 'something',
116 # Each of these hits the DB individually.
117 my $count = $cd_rs->count;
118 my $most_recent = $cd_rs->get_column('date_released')->max();
119 my @records = $cd_rs->all;
121 And it's not just limited to SELECT statements.
127 $cd_rs->create({ artist => 'Fred' });
129 Which is the same as:
131 $schema->resultset('CD')->create({
132 title => 'something',
137 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
141 If a resultset is used in a numeric context it returns the L</count>.
142 However, if it is used in a booleand context it is always true. So if
143 you want to check if a resultset has any results use C<if $rs != 0>.
144 C<if $rs> will always be true.
152 =item Arguments: $source, \%$attrs
154 =item Return Value: $rs
158 The resultset constructor. Takes a source object (usually a
159 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
160 L</ATTRIBUTES> below). Does not perform any queries -- these are
161 executed as needed by the other methods.
163 Generally you won't need to construct a resultset manually. You'll
164 automatically get one from e.g. a L</search> called in scalar context:
166 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
168 IMPORTANT: If called on an object, proxies to new_result instead so
170 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
172 will return a CD object, not a ResultSet.
178 return $class->new_result(@_) if ref $class;
180 my ($source, $attrs) = @_;
181 $source = $source->handle
182 unless $source->isa('DBIx::Class::ResultSourceHandle');
183 $attrs = { %{$attrs||{}} };
185 if ($attrs->{page}) {
186 $attrs->{rows} ||= 10;
189 $attrs->{alias} ||= 'me';
191 # Creation of {} and bless separated to mitigate RH perl bug
192 # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
194 _source_handle => $source,
195 cond => $attrs->{where},
204 $attrs->{result_class} || $source->resolve->result_class
214 =item Arguments: $cond, \%attrs?
216 =item Return Value: $resultset (scalar context), @row_objs (list context)
220 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
221 my $new_rs = $cd_rs->search({ year => 2005 });
223 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
224 # year = 2005 OR year = 2004
226 If you need to pass in additional attributes but no additional condition,
227 call it as C<search(undef, \%attrs)>.
229 # "SELECT name, artistid FROM $artist_table"
230 my @all_artists = $schema->resultset('Artist')->search(undef, {
231 columns => [qw/name artistid/],
234 For a list of attributes that can be passed to C<search>, see
235 L</ATTRIBUTES>. For more examples of using this function, see
236 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
237 documentation for the first argument, see L<SQL::Abstract>.
239 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
245 my $rs = $self->search_rs( @_ );
246 return (wantarray ? $rs->all : $rs);
253 =item Arguments: $cond, \%attrs?
255 =item Return Value: $resultset
259 This method does the same exact thing as search() except it will
260 always return a resultset, even in list context.
268 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
269 my $our_attrs = { %{$self->{attrs}} };
270 my $having = delete $our_attrs->{having};
271 my $where = delete $our_attrs->{where};
275 my %safe = (alias => 1, cache => 1);
278 (@_ && defined($_[0])) # @_ == () or (undef)
280 (keys %$attrs # empty attrs or only 'safe' attrs
281 && List::Util::first { !$safe{$_} } keys %$attrs)
283 # no search, effectively just a clone
284 $rows = $self->get_cache;
287 my $new_attrs = { %{$our_attrs}, %{$attrs} };
289 # merge new attrs into inherited
290 foreach my $key (qw/join prefetch +select +as/) {
291 next unless exists $attrs->{$key};
292 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
297 (@_ == 1 || ref $_[0] eq "HASH")
299 (ref $_[0] eq 'HASH')
301 (keys %{ $_[0] } > 0)
309 ? $self->throw_exception("Odd number of arguments to search")
316 if (defined $where) {
317 $new_attrs->{where} = (
318 defined $new_attrs->{where}
321 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
322 } $where, $new_attrs->{where}
329 $new_attrs->{where} = (
330 defined $new_attrs->{where}
333 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
334 } $cond, $new_attrs->{where}
340 if (defined $having) {
341 $new_attrs->{having} = (
342 defined $new_attrs->{having}
345 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
346 } $having, $new_attrs->{having}
352 my $rs = (ref $self)->new($self->result_source, $new_attrs);
354 $rs->set_cache($rows);
359 =head2 search_literal
363 =item Arguments: $sql_fragment, @bind_values
365 =item Return Value: $resultset (scalar context), @row_objs (list context)
369 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
370 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
372 Pass a literal chunk of SQL to be added to the conditional part of the
375 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
376 only be used in that context. There are known problems using C<search_literal>
377 in chained queries; it can result in bind values in the wrong order. See
378 L<DBIx::Class::Manual::Cookbook/Searching> and
379 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
380 require C<search_literal>.
385 my ($self, $cond, @vals) = @_;
386 my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
387 $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ];
388 return $self->search(\$cond, $attrs);
395 =item Arguments: @values | \%cols, \%attrs?
397 =item Return Value: $row_object | undef
401 Finds a row based on its primary key or unique constraint. For example, to find
402 a row by its primary key:
404 my $cd = $schema->resultset('CD')->find(5);
406 You can also find a row by a specific unique constraint using the C<key>
407 attribute. For example:
409 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
410 key => 'cd_artist_title'
413 Additionally, you can specify the columns explicitly by name:
415 my $cd = $schema->resultset('CD')->find(
417 artist => 'Massive Attack',
418 title => 'Mezzanine',
420 { key => 'cd_artist_title' }
423 If the C<key> is specified as C<primary>, it searches only on the primary key.
425 If no C<key> is specified, it searches on all unique constraints defined on the
426 source for which column data is provided, including the primary key.
428 If your table does not have a primary key, you B<must> provide a value for the
429 C<key> attribute matching one of the unique constraints on the source.
431 In addition to C<key>, L</find> recognizes and applies standard
432 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
434 Note: If your query does not return only one row, a warning is generated:
436 Query returned more than one row
438 See also L</find_or_create> and L</update_or_create>. For information on how to
439 declare unique constraints, see
440 L<DBIx::Class::ResultSource/add_unique_constraint>.
446 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
448 # Default to the primary key, but allow a specific key
449 my @cols = exists $attrs->{key}
450 ? $self->result_source->unique_constraint_columns($attrs->{key})
451 : $self->result_source->primary_columns;
452 $self->throw_exception(
453 "Can't find unless a primary key is defined or unique constraint is specified"
456 # Parse out a hashref from input
458 if (ref $_[0] eq 'HASH') {
459 $input_query = { %{$_[0]} };
461 elsif (@_ == @cols) {
463 @{$input_query}{@cols} = @_;
466 # Compatibility: Allow e.g. find(id => $value)
467 carp "Find by key => value deprecated; please use a hashref instead";
471 my (%related, $info);
473 KEY: foreach my $key (keys %$input_query) {
474 if (ref($input_query->{$key})
475 && ($info = $self->result_source->relationship_info($key))) {
476 my $val = delete $input_query->{$key};
477 next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
478 my $rel_q = $self->result_source->resolve_condition(
479 $info->{cond}, $val, $key
481 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
482 @related{keys %$rel_q} = values %$rel_q;
485 if (my @keys = keys %related) {
486 @{$input_query}{@keys} = values %related;
490 # Build the final query: Default to the disjunction of the unique queries,
491 # but allow the input query in case the ResultSet defines the query or the
492 # user is abusing find
493 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
495 if (exists $attrs->{key}) {
496 my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key});
497 my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
498 $query = $self->_add_alias($unique_query, $alias);
501 my @unique_queries = $self->_unique_queries($input_query, $attrs);
502 $query = @unique_queries
503 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
504 : $self->_add_alias($input_query, $alias);
509 my $rs = $self->search($query, $attrs);
510 if (keys %{$rs->_resolved_attrs->{collapse}}) {
512 carp "Query returned more than one row" if $rs->next;
520 if (keys %{$self->_resolved_attrs->{collapse}}) {
521 my $rs = $self->search($query);
523 carp "Query returned more than one row" if $rs->next;
527 return $self->single($query);
534 # Add the specified alias to the specified query hash. A copy is made so the
535 # original query is not modified.
538 my ($self, $query, $alias) = @_;
540 my %aliased = %$query;
541 foreach my $col (grep { ! m/\./ } keys %aliased) {
542 $aliased{"$alias.$col"} = delete $aliased{$col};
550 # Build a list of queries which satisfy unique constraints.
552 sub _unique_queries {
553 my ($self, $query, $attrs) = @_;
555 my @constraint_names = exists $attrs->{key}
557 : $self->result_source->unique_constraint_names;
559 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
560 my $num_where = scalar keys %$where;
563 foreach my $name (@constraint_names) {
564 my @unique_cols = $self->result_source->unique_constraint_columns($name);
565 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
567 my $num_cols = scalar @unique_cols;
568 my $num_query = scalar keys %$unique_query;
570 my $total = $num_query + $num_where;
571 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
572 # The query is either unique on its own or is unique in combination with
573 # the existing where clause
574 push @unique_queries, $unique_query;
578 return @unique_queries;
581 # _build_unique_query
583 # Constrain the specified query hash based on the specified column names.
585 sub _build_unique_query {
586 my ($self, $query, $unique_cols) = @_;
589 map { $_ => $query->{$_} }
590 grep { exists $query->{$_} }
595 =head2 search_related
599 =item Arguments: $rel, $cond, \%attrs?
601 =item Return Value: $new_resultset
605 $new_rs = $cd_rs->search_related('artist', {
609 Searches the specified relationship, optionally specifying a condition and
610 attributes for matching records. See L</ATTRIBUTES> for more information.
615 return shift->related_resultset(shift)->search(@_);
618 =head2 search_related_rs
620 This method works exactly the same as search_related, except that
621 it guarantees a restultset, even in list context.
625 sub search_related_rs {
626 return shift->related_resultset(shift)->search_rs(@_);
633 =item Arguments: none
635 =item Return Value: $cursor
639 Returns a storage-driven cursor to the given resultset. See
640 L<DBIx::Class::Cursor> for more information.
647 my $attrs = { %{$self->_resolved_attrs} };
648 return $self->{cursor}
649 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
650 $attrs->{where},$attrs);
657 =item Arguments: $cond?
659 =item Return Value: $row_object?
663 my $cd = $schema->resultset('CD')->single({ year => 2001 });
665 Inflates the first result without creating a cursor if the resultset has
666 any records in it; if not returns nothing. Used by L</find> as a lean version of
669 While this method can take an optional search condition (just like L</search>)
670 being a fast-code-path it does not recognize search attributes. If you need to
671 add extra joins or similar, call L</search> and then chain-call L</single> on the
672 L<DBIx::Class::ResultSet> returned.
678 As of 0.08100, this method enforces the assumption that the preceeding
679 query returns only one row. If more than one row is returned, you will receive
682 Query returned more than one row
684 In this case, you should be using L</first> or L</find> instead, or if you really
685 know what you are doing, use the L</rows> attribute to explicitly limit the size
693 my ($self, $where) = @_;
695 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
698 my $attrs = { %{$self->_resolved_attrs} };
700 if (defined $attrs->{where}) {
703 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
704 $where, delete $attrs->{where} ]
707 $attrs->{where} = $where;
711 # XXX: Disabled since it doesn't infer uniqueness in all cases
712 # unless ($self->_is_unique_query($attrs->{where})) {
713 # carp "Query not guaranteed to return a single row"
714 # . "; please declare your unique constraints or use search instead";
717 my @data = $self->result_source->storage->select_single(
718 $attrs->{from}, $attrs->{select},
719 $attrs->{where}, $attrs
722 return (@data ? ($self->_construct_object(@data))[0] : undef);
727 # Try to determine if the specified query is guaranteed to be unique, based on
728 # the declared unique constraints.
730 sub _is_unique_query {
731 my ($self, $query) = @_;
733 my $collapsed = $self->_collapse_query($query);
734 my $alias = $self->{attrs}{alias};
736 foreach my $name ($self->result_source->unique_constraint_names) {
737 my @unique_cols = map {
739 } $self->result_source->unique_constraint_columns($name);
741 # Count the values for each unique column
742 my %seen = map { $_ => 0 } @unique_cols;
744 foreach my $key (keys %$collapsed) {
745 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
746 next unless exists $seen{$aliased}; # Additional constraints are okay
747 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
750 # If we get 0 or more than 1 value for a column, it's not necessarily unique
751 return 1 unless grep { $_ != 1 } values %seen;
759 # Recursively collapse the query, accumulating values for each column.
761 sub _collapse_query {
762 my ($self, $query, $collapsed) = @_;
766 if (ref $query eq 'ARRAY') {
767 foreach my $subquery (@$query) {
768 next unless ref $subquery; # -or
769 # warn "ARRAY: " . Dumper $subquery;
770 $collapsed = $self->_collapse_query($subquery, $collapsed);
773 elsif (ref $query eq 'HASH') {
774 if (keys %$query and (keys %$query)[0] eq '-and') {
775 foreach my $subquery (@{$query->{-and}}) {
776 # warn "HASH: " . Dumper $subquery;
777 $collapsed = $self->_collapse_query($subquery, $collapsed);
781 # warn "LEAF: " . Dumper $query;
782 foreach my $col (keys %$query) {
783 my $value = $query->{$col};
784 $collapsed->{$col}{$value}++;
796 =item Arguments: $cond?
798 =item Return Value: $resultsetcolumn
802 my $max_length = $rs->get_column('length')->max;
804 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
809 my ($self, $column) = @_;
810 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
818 =item Arguments: $cond, \%attrs?
820 =item Return Value: $resultset (scalar context), @row_objs (list context)
824 # WHERE title LIKE '%blue%'
825 $cd_rs = $rs->search_like({ title => '%blue%'});
827 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
828 that this is simply a convenience method retained for ex Class::DBI users.
829 You most likely want to use L</search> with specific operators.
831 For more information, see L<DBIx::Class::Manual::Cookbook>.
837 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
838 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
839 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
840 return $class->search($query, { %$attrs });
847 =item Arguments: $first, $last
849 =item Return Value: $resultset (scalar context), @row_objs (list context)
853 Returns a resultset or object list representing a subset of elements from the
854 resultset slice is called on. Indexes are from 0, i.e., to get the first
857 my ($one, $two, $three) = $rs->slice(0, 2);
862 my ($self, $min, $max) = @_;
863 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
864 $attrs->{offset} = $self->{attrs}{offset} || 0;
865 $attrs->{offset} += $min;
866 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
867 return $self->search(undef(), $attrs);
868 #my $slice = (ref $self)->new($self->result_source, $attrs);
869 #return (wantarray ? $slice->all : $slice);
876 =item Arguments: none
878 =item Return Value: $result?
882 Returns the next element in the resultset (C<undef> is there is none).
884 Can be used to efficiently iterate over records in the resultset:
886 my $rs = $schema->resultset('CD')->search;
887 while (my $cd = $rs->next) {
891 Note that you need to store the resultset object, and call C<next> on it.
892 Calling C<< resultset('Table')->next >> repeatedly will always return the
893 first record from the resultset.
899 if (my $cache = $self->get_cache) {
900 $self->{all_cache_position} ||= 0;
901 return $cache->[$self->{all_cache_position}++];
903 if ($self->{attrs}{cache}) {
904 $self->{all_cache_position} = 1;
905 return ($self->all)[0];
907 if ($self->{stashed_objects}) {
908 my $obj = shift(@{$self->{stashed_objects}});
909 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
913 exists $self->{stashed_row}
914 ? @{delete $self->{stashed_row}}
915 : $self->cursor->next
917 return undef unless (@row);
918 my ($row, @more) = $self->_construct_object(@row);
919 $self->{stashed_objects} = \@more if @more;
923 sub _construct_object {
924 my ($self, @row) = @_;
925 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
926 my @new = $self->result_class->inflate_result($self->result_source, @$info);
927 @new = $self->{_attrs}{record_filter}->(@new)
928 if exists $self->{_attrs}{record_filter};
932 sub _collapse_result {
933 my ($self, $as_proto, $row) = @_;
937 # 'foo' => [ undef, 'foo' ]
938 # 'foo.bar' => [ 'foo', 'bar' ]
939 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
941 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
943 my %collapse = %{$self->{_attrs}{collapse}||{}};
947 # if we're doing collapsing (has_many prefetch) we need to grab records
948 # until the PK changes, so fill @pri_index. if not, we leave it empty so
949 # we know we don't have to bother.
951 # the reason for not using the collapse stuff directly is because if you
952 # had for e.g. two artists in a row with no cds, the collapse info for
953 # both would be NULL (undef) so you'd lose the second artist
955 # store just the index so we can check the array positions from the row
956 # without having to contruct the full hash
958 if (keys %collapse) {
959 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
960 foreach my $i (0 .. $#construct_as) {
961 next if defined($construct_as[$i][0]); # only self table
962 if (delete $pri{$construct_as[$i][1]}) {
963 push(@pri_index, $i);
965 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
969 # no need to do an if, it'll be empty if @pri_index is empty anyway
971 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
975 do { # no need to check anything at the front, we always want the first row
979 foreach my $this_as (@construct_as) {
980 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
983 push(@const_rows, \%const);
985 } until ( # no pri_index => no collapse => drop straight out
988 do { # get another row, stash it, drop out if different PK
990 @copy = $self->cursor->next;
991 $self->{stashed_row} = \@copy;
993 # last thing in do block, counts as true if anything doesn't match
995 # check xor defined first for NULL vs. NOT NULL then if one is
996 # defined the other must be so check string equality
999 (defined $pri_vals{$_} ^ defined $copy[$_])
1000 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1005 my $alias = $self->{attrs}{alias};
1012 foreach my $const (@const_rows) {
1013 scalar @const_keys or do {
1014 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1016 foreach my $key (@const_keys) {
1019 my @parts = split(/\./, $key);
1021 my $data = $const->{$key};
1022 foreach my $p (@parts) {
1023 $target = $target->[1]->{$p} ||= [];
1025 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1026 # collapsing at this point and on final part
1027 my $pos = $collapse_pos{$cur};
1028 CK: foreach my $ck (@ckey) {
1029 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1030 $collapse_pos{$cur} = $data;
1031 delete @collapse_pos{ # clear all positioning for sub-entries
1032 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1039 if (exists $collapse{$cur}) {
1040 $target = $target->[-1];
1043 $target->[0] = $data;
1045 $info->[0] = $const->{$key};
1053 =head2 result_source
1057 =item Arguments: $result_source?
1059 =item Return Value: $result_source
1063 An accessor for the primary ResultSource object from which this ResultSet
1070 =item Arguments: $result_class?
1072 =item Return Value: $result_class
1076 An accessor for the class to use when creating row objects. Defaults to
1077 C<< result_source->result_class >> - which in most cases is the name of the
1078 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1083 my ($self, $result_class) = @_;
1084 if ($result_class) {
1085 $self->ensure_class_loaded($result_class);
1086 $self->_result_class($result_class);
1088 $self->_result_class;
1095 =item Arguments: $cond, \%attrs??
1097 =item Return Value: $count
1101 Performs an SQL C<COUNT> with the same query as the resultset was built
1102 with to find the number of elements. If passed arguments, does a search
1103 on the resultset and counts the results of that.
1105 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1106 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1107 not support C<DISTINCT> with multiple columns. If you are using such a
1108 database, you should only use columns from the main table in your C<group_by>
1115 return $self->search(@_)->count if @_ and defined $_[0];
1116 return scalar @{ $self->get_cache } if $self->get_cache;
1117 my $count = $self->_count;
1118 return 0 unless $count;
1120 # need to take offset from resolved attrs
1122 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1123 $count = $self->{attrs}{rows} if
1124 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1125 $count = 0 if ($count < 0);
1129 sub _count { # Separated out so pager can get the full count
1131 my $select = { count => '*' };
1133 my $attrs = { %{$self->_resolved_attrs} };
1134 if (my $group_by = delete $attrs->{group_by}) {
1135 delete $attrs->{having};
1136 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1137 # todo: try CONCAT for multi-column pk
1138 my @pk = $self->result_source->primary_columns;
1140 my $alias = $attrs->{alias};
1141 foreach my $column (@distinct) {
1142 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1143 @distinct = ($column);
1149 $select = { count => { distinct => \@distinct } };
1152 $attrs->{select} = $select;
1153 $attrs->{as} = [qw/count/];
1155 # offset, order by and page are not needed to count. record_filter is cdbi
1156 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1158 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1159 my ($count) = $tmp_rs->cursor->next;
1167 =head2 count_literal
1171 =item Arguments: $sql_fragment, @bind_values
1173 =item Return Value: $count
1177 Counts the results in a literal query. Equivalent to calling L</search_literal>
1178 with the passed arguments, then L</count>.
1182 sub count_literal { shift->search_literal(@_)->count; }
1188 =item Arguments: none
1190 =item Return Value: @objects
1194 Returns all elements in the resultset. Called implicitly if the resultset
1195 is returned in list context.
1202 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1205 return @{ $self->get_cache } if $self->get_cache;
1209 # TODO: don't call resolve here
1210 if (keys %{$self->_resolved_attrs->{collapse}}) {
1211 # if ($self->{attrs}{prefetch}) {
1212 # Using $self->cursor->all is really just an optimisation.
1213 # If we're collapsing has_many prefetches it probably makes
1214 # very little difference, and this is cleaner than hacking
1215 # _construct_object to survive the approach
1216 my @row = $self->cursor->next;
1218 push(@obj, $self->_construct_object(@row));
1219 @row = (exists $self->{stashed_row}
1220 ? @{delete $self->{stashed_row}}
1221 : $self->cursor->next);
1224 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1227 $self->set_cache(\@obj) if $self->{attrs}{cache};
1235 =item Arguments: none
1237 =item Return Value: $self
1241 Resets the resultset's cursor, so you can iterate through the elements again.
1247 delete $self->{_attrs} if exists $self->{_attrs};
1248 $self->{all_cache_position} = 0;
1249 $self->cursor->reset;
1257 =item Arguments: none
1259 =item Return Value: $object?
1263 Resets the resultset and returns an object for the first result (if the
1264 resultset returns anything).
1269 return $_[0]->reset->next;
1272 # _cond_for_update_delete
1274 # update/delete require the condition to be modified to handle
1275 # the differing SQL syntax available. This transforms the $self->{cond}
1276 # appropriately, returning the new condition.
1278 sub _cond_for_update_delete {
1279 my ($self, $full_cond) = @_;
1282 $full_cond ||= $self->{cond};
1283 # No-op. No condition, we're updating/deleting everything
1284 return $cond unless ref $full_cond;
1286 if (ref $full_cond eq 'ARRAY') {
1290 foreach my $key (keys %{$_}) {
1292 $hash{$1} = $_->{$key};
1298 elsif (ref $full_cond eq 'HASH') {
1299 if ((keys %{$full_cond})[0] eq '-and') {
1302 my @cond = @{$full_cond->{-and}};
1303 for (my $i = 0; $i < @cond; $i++) {
1304 my $entry = $cond[$i];
1307 if (ref $entry eq 'HASH') {
1308 $hash = $self->_cond_for_update_delete($entry);
1311 $entry =~ /([^.]+)$/;
1312 $hash->{$1} = $cond[++$i];
1315 push @{$cond->{-and}}, $hash;
1319 foreach my $key (keys %{$full_cond}) {
1321 $cond->{$1} = $full_cond->{$key};
1326 $self->throw_exception(
1327 "Can't update/delete on resultset with condition unless hash or array"
1339 =item Arguments: \%values
1341 =item Return Value: $storage_rv
1345 Sets the specified columns in the resultset to the supplied values in a
1346 single query. Return value will be true if the update succeeded or false
1347 if no records were updated; exact type of success value is storage-dependent.
1352 my ($self, $values) = @_;
1353 $self->throw_exception("Values for update must be a hash")
1354 unless ref $values eq 'HASH';
1356 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1357 . ' on joined resultsets, and may affect rows well outside of the'
1358 . ' contents of $rs. Use at your own risk' )
1359 if ( $self->{attrs}{seen_join} );
1361 my $cond = $self->_cond_for_update_delete;
1363 return $self->result_source->storage->update(
1364 $self->result_source, $values, $cond
1372 =item Arguments: \%values
1374 =item Return Value: 1
1378 Fetches all objects and updates them one at a time. Note that C<update_all>
1379 will run DBIC cascade triggers, while L</update> will not.
1384 my ($self, $values) = @_;
1385 $self->throw_exception("Values for update must be a hash")
1386 unless ref $values eq 'HASH';
1387 foreach my $obj ($self->all) {
1388 $obj->set_columns($values)->update;
1397 =item Arguments: none
1399 =item Return Value: 1
1403 Deletes the contents of the resultset from its result source. Note that this
1404 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1405 to run. See also L<DBIx::Class::Row/delete>.
1407 delete may not generate correct SQL for a query with joins or a resultset
1408 chained from a related resultset. In this case it will generate a warning:-
1410 WARNING! Currently $rs->delete() does not generate proper SQL on
1411 joined resultsets, and may delete rows well outside of the contents
1412 of $rs. Use at your own risk
1414 In these cases you may find that delete_all is more appropriate, or you
1415 need to respecify your query in a way that can be expressed without a join.
1421 $self->throw_exception("Delete should not be passed any arguments")
1423 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1424 . ' on joined resultsets, and may delete rows well outside of the'
1425 . ' contents of $rs. Use at your own risk' )
1426 if ( $self->{attrs}{seen_join} );
1427 my $cond = $self->_cond_for_update_delete;
1429 $self->result_source->storage->delete($self->result_source, $cond);
1437 =item Arguments: none
1439 =item Return Value: 1
1443 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1444 will run DBIC cascade triggers, while L</delete> will not.
1450 $_->delete for $self->all;
1458 =item Arguments: \@data;
1462 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1463 For the arrayref of hashrefs style each hashref should be a structure suitable
1464 forsubmitting to a $resultset->create(...) method.
1466 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1467 to insert the data, as this is a faster method.
1469 Otherwise, each set of data is inserted into the database using
1470 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1471 objects is returned.
1473 Example: Assuming an Artist Class that has many CDs Classes relating:
1475 my $Artist_rs = $schema->resultset("Artist");
1477 ## Void Context Example
1478 $Artist_rs->populate([
1479 { artistid => 4, name => 'Manufactured Crap', cds => [
1480 { title => 'My First CD', year => 2006 },
1481 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1484 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1485 { title => 'My parents sold me to a record company' ,year => 2005 },
1486 { title => 'Why Am I So Ugly?', year => 2006 },
1487 { title => 'I Got Surgery and am now Popular', year => 2007 }
1492 ## Array Context Example
1493 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1494 { name => "Artist One"},
1495 { name => "Artist Two"},
1496 { name => "Artist Three", cds=> [
1497 { title => "First CD", year => 2007},
1498 { title => "Second CD", year => 2008},
1502 print $ArtistOne->name; ## response is 'Artist One'
1503 print $ArtistThree->cds->count ## reponse is '2'
1505 For the arrayref of arrayrefs style, the first element should be a list of the
1506 fieldsnames to which the remaining elements are rows being inserted. For
1509 $Arstist_rs->populate([
1510 [qw/artistid name/],
1511 [100, 'A Formally Unknown Singer'],
1512 [101, 'A singer that jumped the shark two albums ago'],
1513 [102, 'An actually cool singer.'],
1516 Please note an important effect on your data when choosing between void and
1517 wantarray context. Since void context goes straight to C<insert_bulk> in
1518 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1519 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1520 create primary keys for you, you will find that your PKs are empty. In this
1521 case you will have to use the wantarray context in order to create those
1527 my $self = shift @_;
1528 my $data = ref $_[0][0] eq 'HASH'
1529 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1530 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1532 if(defined wantarray) {
1534 foreach my $item (@$data) {
1535 push(@created, $self->create($item));
1539 my ($first, @rest) = @$data;
1541 my @names = grep {!ref $first->{$_}} keys %$first;
1542 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1543 my @pks = $self->result_source->primary_columns;
1545 ## do the belongs_to relationships
1546 foreach my $index (0..$#$data) {
1547 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1548 my @ret = $self->populate($data);
1552 foreach my $rel (@rels) {
1553 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1554 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1555 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1556 my $related = $result->result_source->resolve_condition(
1557 $result->result_source->relationship_info($reverse)->{cond},
1562 delete $data->[$index]->{$rel};
1563 $data->[$index] = {%{$data->[$index]}, %$related};
1565 push @names, keys %$related if $index == 0;
1569 ## do bulk insert on current row
1570 my @values = map { [ @$_{@names} ] } @$data;
1572 $self->result_source->storage->insert_bulk(
1573 $self->result_source,
1578 ## do the has_many relationships
1579 foreach my $item (@$data) {
1581 foreach my $rel (@rels) {
1582 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1584 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1585 || $self->throw_exception('Cannot find the relating object.');
1587 my $child = $parent->$rel;
1589 my $related = $child->result_source->resolve_condition(
1590 $parent->result_source->relationship_info($rel)->{cond},
1595 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1596 my @populate = map { {%$_, %$related} } @rows_to_add;
1598 $child->populate( \@populate );
1604 =head2 _normalize_populate_args ($args)
1606 Private method used by L</populate> to normalize its incoming arguments. Factored
1607 out in case you want to subclass and accept new argument structures to the
1608 L</populate> method.
1612 sub _normalize_populate_args {
1613 my ($self, $data) = @_;
1614 my @names = @{shift(@$data)};
1615 my @results_to_create;
1616 foreach my $datum (@$data) {
1617 my %result_to_create;
1618 foreach my $index (0..$#names) {
1619 $result_to_create{$names[$index]} = $$datum[$index];
1621 push @results_to_create, \%result_to_create;
1623 return \@results_to_create;
1630 =item Arguments: none
1632 =item Return Value: $pager
1636 Return Value a L<Data::Page> object for the current resultset. Only makes
1637 sense for queries with a C<page> attribute.
1643 my $attrs = $self->{attrs};
1644 $self->throw_exception("Can't create pager for non-paged rs")
1645 unless $self->{attrs}{page};
1646 $attrs->{rows} ||= 10;
1647 return $self->{pager} ||= Data::Page->new(
1648 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1655 =item Arguments: $page_number
1657 =item Return Value: $rs
1661 Returns a resultset for the $page_number page of the resultset on which page
1662 is called, where each page contains a number of rows equal to the 'rows'
1663 attribute set on the resultset (10 by default).
1668 my ($self, $page) = @_;
1669 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1676 =item Arguments: \%vals
1678 =item Return Value: $rowobject
1682 Creates a new row object in the resultset's result class and returns
1683 it. The row is not inserted into the database at this point, call
1684 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1685 will tell you whether the row object has been inserted or not.
1687 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1692 my ($self, $values) = @_;
1693 $self->throw_exception( "new_result needs a hash" )
1694 unless (ref $values eq 'HASH');
1697 my $alias = $self->{attrs}{alias};
1700 defined $self->{cond}
1701 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1703 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1704 $new{-from_resultset} = [ keys %new ] if keys %new;
1706 $self->throw_exception(
1707 "Can't abstract implicit construct, condition not a hash"
1708 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1710 my $collapsed_cond = (
1712 ? $self->_collapse_cond($self->{cond})
1716 # precendence must be given to passed values over values inherited from
1717 # the cond, so the order here is important.
1718 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1719 while( my($col,$value) = each %implied ){
1720 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1721 $new{$col} = $value->{'='};
1724 $new{$col} = $value if $self->_is_deterministic_value($value);
1730 %{ $self->_remove_alias($values, $alias) },
1731 -source_handle => $self->_source_handle,
1732 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1735 return $self->result_class->new(\%new);
1738 # _is_deterministic_value
1740 # Make an effor to strip non-deterministic values from the condition,
1741 # to make sure new_result chokes less
1743 sub _is_deterministic_value {
1746 my $ref_type = ref $value;
1747 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1748 return 1 if Scalar::Util::blessed($value);
1754 # Recursively collapse the condition.
1756 sub _collapse_cond {
1757 my ($self, $cond, $collapsed) = @_;
1761 if (ref $cond eq 'ARRAY') {
1762 foreach my $subcond (@$cond) {
1763 next unless ref $subcond; # -or
1764 # warn "ARRAY: " . Dumper $subcond;
1765 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1768 elsif (ref $cond eq 'HASH') {
1769 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1770 foreach my $subcond (@{$cond->{-and}}) {
1771 # warn "HASH: " . Dumper $subcond;
1772 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1776 # warn "LEAF: " . Dumper $cond;
1777 foreach my $col (keys %$cond) {
1778 my $value = $cond->{$col};
1779 $collapsed->{$col} = $value;
1789 # Remove the specified alias from the specified query hash. A copy is made so
1790 # the original query is not modified.
1793 my ($self, $query, $alias) = @_;
1795 my %orig = %{ $query || {} };
1798 foreach my $key (keys %orig) {
1800 $unaliased{$key} = $orig{$key};
1803 $unaliased{$1} = $orig{$key}
1804 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1810 =head2 as_query (EXPERIMENTAL)
1814 =item Arguments: none
1816 =item Return Value: \[ $sql, @bind ]
1820 Returns the SQL query and bind vars associated with the invocant.
1822 This is generally used as the RHS for a subquery.
1824 B<NOTE>: This feature is still experimental.
1828 sub as_query { return shift->cursor->as_query(@_) }
1834 =item Arguments: \%vals, \%attrs?
1836 =item Return Value: $rowobject
1840 my $artist = $schema->resultset('Artist')->find_or_new(
1841 { artist => 'fred' }, { key => 'artists' });
1843 $cd->cd_to_producer->find_or_new({ producer => $producer },
1844 { key => 'primary });
1846 Find an existing record from this resultset, based on its primary
1847 key, or a unique constraint. If none exists, instantiate a new result
1848 object and return it. The object will not be saved into your storage
1849 until you call L<DBIx::Class::Row/insert> on it.
1851 You most likely want this method when looking for existing rows using
1852 a unique constraint that is not the primary key, or looking for
1855 If you want objects to be saved immediately, use L</find_or_create> instead.
1857 B<Note>: C<find_or_new> is probably not what you want when creating a
1858 new row in a table that uses primary keys supplied by the
1859 database. Passing in a primary key column with a value of I<undef>
1860 will cause L</find> to attempt to search for a row with a value of
1867 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1868 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1869 my $exists = $self->find($hash, $attrs);
1870 return defined $exists ? $exists : $self->new_result($hash);
1877 =item Arguments: \%vals
1879 =item Return Value: a L<DBIx::Class::Row> $object
1883 Attempt to create a single new row or a row with multiple related rows
1884 in the table represented by the resultset (and related tables). This
1885 will not check for duplicate rows before inserting, use
1886 L</find_or_create> to do that.
1888 To create one row for this resultset, pass a hashref of key/value
1889 pairs representing the columns of the table and the values you wish to
1890 store. If the appropriate relationships are set up, foreign key fields
1891 can also be passed an object representing the foreign row, and the
1892 value will be set to its primary key.
1894 To create related objects, pass a hashref for the value if the related
1895 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1896 and use the name of the relationship as the key. (NOT the name of the field,
1897 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1898 of hashrefs containing the data for each of the rows to create in the foreign
1899 tables, again using the relationship name as the key.
1901 Instead of hashrefs of plain related data (key/value pairs), you may
1902 also pass new or inserted objects. New objects (not inserted yet, see
1903 L</new>), will be inserted into their appropriate tables.
1905 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1907 Example of creating a new row.
1909 $person_rs->create({
1910 name=>"Some Person",
1911 email=>"somebody@someplace.com"
1914 Example of creating a new row and also creating rows in a related C<has_many>
1915 or C<has_one> resultset. Note Arrayref.
1918 { artistid => 4, name => 'Manufactured Crap', cds => [
1919 { title => 'My First CD', year => 2006 },
1920 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1925 Example of creating a new row and also creating a row in a related
1926 C<belongs_to>resultset. Note Hashref.
1929 title=>"Music for Silly Walks",
1932 name=>"Silly Musician",
1939 my ($self, $attrs) = @_;
1940 $self->throw_exception( "create needs a hashref" )
1941 unless ref $attrs eq 'HASH';
1942 return $self->new_result($attrs)->insert;
1945 =head2 find_or_create
1949 =item Arguments: \%vals, \%attrs?
1951 =item Return Value: $rowobject
1955 $cd->cd_to_producer->find_or_create({ producer => $producer },
1956 { key => 'primary });
1958 Tries to find a record based on its primary key or unique constraints; if none
1959 is found, creates one and returns that instead.
1961 my $cd = $schema->resultset('CD')->find_or_create({
1963 artist => 'Massive Attack',
1964 title => 'Mezzanine',
1968 Also takes an optional C<key> attribute, to search by a specific key or unique
1969 constraint. For example:
1971 my $cd = $schema->resultset('CD')->find_or_create(
1973 artist => 'Massive Attack',
1974 title => 'Mezzanine',
1976 { key => 'cd_artist_title' }
1979 B<Note>: Because find_or_create() reads from the database and then
1980 possibly inserts based on the result, this method is subject to a race
1981 condition. Another process could create a record in the table after
1982 the find has completed and before the create has started. To avoid
1983 this problem, use find_or_create() inside a transaction.
1985 B<Note>: C<find_or_create> is probably not what you want when creating
1986 a new row in a table that uses primary keys supplied by the
1987 database. Passing in a primary key column with a value of I<undef>
1988 will cause L</find> to attempt to search for a row with a value of
1991 See also L</find> and L</update_or_create>. For information on how to declare
1992 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1996 sub find_or_create {
1998 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1999 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2000 my $exists = $self->find($hash, $attrs);
2001 return defined $exists ? $exists : $self->create($hash);
2004 =head2 update_or_create
2008 =item Arguments: \%col_values, { key => $unique_constraint }?
2010 =item Return Value: $rowobject
2014 $resultset->update_or_create({ col => $val, ... });
2016 First, searches for an existing row matching one of the unique constraints
2017 (including the primary key) on the source of this resultset. If a row is
2018 found, updates it with the other given column values. Otherwise, creates a new
2021 Takes an optional C<key> attribute to search on a specific unique constraint.
2024 # In your application
2025 my $cd = $schema->resultset('CD')->update_or_create(
2027 artist => 'Massive Attack',
2028 title => 'Mezzanine',
2031 { key => 'cd_artist_title' }
2034 $cd->cd_to_producer->update_or_create({
2035 producer => $producer,
2042 If no C<key> is specified, it searches on all unique constraints defined on the
2043 source, including the primary key.
2045 If the C<key> is specified as C<primary>, it searches only on the primary key.
2047 See also L</find> and L</find_or_create>. For information on how to declare
2048 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2050 B<Note>: C<update_or_create> is probably not what you want when
2051 looking for a row in a table that uses primary keys supplied by the
2052 database, unless you actually have a key value. Passing in a primary
2053 key column with a value of I<undef> will cause L</find> to attempt to
2054 search for a row with a value of I<NULL>.
2058 sub update_or_create {
2060 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2061 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2063 my $row = $self->find($cond, $attrs);
2065 $row->update($cond);
2069 return $self->create($cond);
2076 =item Arguments: none
2078 =item Return Value: \@cache_objects?
2082 Gets the contents of the cache for the resultset, if the cache is set.
2084 The cache is populated either by using the L</prefetch> attribute to
2085 L</search> or by calling L</set_cache>.
2097 =item Arguments: \@cache_objects
2099 =item Return Value: \@cache_objects
2103 Sets the contents of the cache for the resultset. Expects an arrayref
2104 of objects of the same class as those produced by the resultset. Note that
2105 if the cache is set the resultset will return the cached objects rather
2106 than re-querying the database even if the cache attr is not set.
2108 The contents of the cache can also be populated by using the
2109 L</prefetch> attribute to L</search>.
2114 my ( $self, $data ) = @_;
2115 $self->throw_exception("set_cache requires an arrayref")
2116 if defined($data) && (ref $data ne 'ARRAY');
2117 $self->{all_cache} = $data;
2124 =item Arguments: none
2126 =item Return Value: []
2130 Clears the cache for the resultset.
2135 shift->set_cache(undef);
2138 =head2 related_resultset
2142 =item Arguments: $relationship_name
2144 =item Return Value: $resultset
2148 Returns a related resultset for the supplied relationship name.
2150 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2154 sub related_resultset {
2155 my ($self, $rel) = @_;
2157 $self->{related_resultsets} ||= {};
2158 return $self->{related_resultsets}{$rel} ||= do {
2159 my $rel_obj = $self->result_source->relationship_info($rel);
2161 $self->throw_exception(
2162 "search_related: result source '" . $self->result_source->source_name .
2163 "' has no such relationship $rel")
2166 my ($from,$seen) = $self->_resolve_from($rel);
2168 my $join_count = $seen->{$rel};
2169 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2171 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2172 my %attrs = %{$self->{attrs}||{}};
2173 delete @attrs{qw(result_class alias)};
2177 if (my $cache = $self->get_cache) {
2178 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2179 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2184 my $rel_source = $self->result_source->related_source($rel);
2188 # The reason we do this now instead of passing the alias to the
2189 # search_rs below is that if you wrap/overload resultset on the
2190 # source you need to know what alias it's -going- to have for things
2191 # to work sanely (e.g. RestrictWithObject wants to be able to add
2192 # extra query restrictions, and these may need to be $alias.)
2194 my $attrs = $rel_source->resultset_attributes;
2195 local $attrs->{alias} = $alias;
2197 $rel_source->resultset
2205 where => $self->{cond},
2210 $new->set_cache($new_cache) if $new_cache;
2215 =head2 current_source_alias
2219 =item Arguments: none
2221 =item Return Value: $source_alias
2225 Returns the current table alias for the result source this resultset is built
2226 on, that will be used in the SQL query. Usually it is C<me>.
2228 Currently the source alias that refers to the result set returned by a
2229 L</search>/L</find> family method depends on how you got to the resultset: it's
2230 C<me> by default, but eg. L</search_related> aliases it to the related result
2231 source name (and keeps C<me> referring to the original result set). The long
2232 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2233 (and make this method unnecessary).
2235 Thus it's currently necessary to use this method in predefined queries (see
2236 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2237 source alias of the current result set:
2239 # in a result set class
2241 my ($self, $user) = @_;
2243 my $me = $self->current_source_alias;
2245 return $self->search(
2246 "$me.modified" => $user->id,
2252 sub current_source_alias {
2255 return ($self->{attrs} || {})->{alias} || 'me';
2259 my ($self, $extra_join) = @_;
2260 my $source = $self->result_source;
2261 my $attrs = $self->{attrs};
2263 my $from = $attrs->{from}
2264 || [ { $attrs->{alias} => $source->from } ];
2266 my $seen = { %{$attrs->{seen_join}||{}} };
2268 my $join = ($attrs->{join}
2269 ? [ $attrs->{join}, $extra_join ]
2272 # we need to take the prefetch the attrs into account before we
2273 # ->resolve_join as otherwise they get lost - captainL
2274 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2278 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2281 return ($from,$seen);
2284 sub _resolved_attrs {
2286 return $self->{_attrs} if $self->{_attrs};
2288 my $attrs = { %{ $self->{attrs} || {} } };
2289 my $source = $self->result_source;
2290 my $alias = $attrs->{alias};
2292 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2295 # build columns (as long as select isn't set) into a set of as/select hashes
2296 unless ( $attrs->{select} ) {
2298 ( ref($_) eq 'HASH' ) ? $_
2301 /^\Q${alias}.\E(.+)$/ ? $1
2303 ) => ( /\./ ? $_ : "${alias}.$_" )
2305 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2307 # add the additional columns on
2308 foreach ( 'include_columns', '+columns' ) {
2309 push @colbits, map {
2310 ( ref($_) eq 'HASH' )
2312 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2313 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2316 # start with initial select items
2317 if ( $attrs->{select} ) {
2319 ( ref $attrs->{select} eq 'ARRAY' )
2320 ? [ @{ $attrs->{select} } ]
2321 : [ $attrs->{select} ];
2325 ref $attrs->{as} eq 'ARRAY'
2326 ? [ @{ $attrs->{as} } ]
2329 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2334 # otherwise we intialise select & as to empty
2335 $attrs->{select} = [];
2339 # now add colbits to select/as
2340 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2341 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2344 if ( $adds = delete $attrs->{'+select'} ) {
2345 $adds = [$adds] unless ref $adds eq 'ARRAY';
2347 @{ $attrs->{select} },
2348 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2351 if ( $adds = delete $attrs->{'+as'} ) {
2352 $adds = [$adds] unless ref $adds eq 'ARRAY';
2353 push( @{ $attrs->{as} }, @$adds );
2356 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2358 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2359 my $join = delete $attrs->{join} || {};
2361 if ( defined $attrs->{prefetch} ) {
2362 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2366 $attrs->{from} = # have to copy here to avoid corrupting the original
2368 @{ $attrs->{from} },
2369 $source->resolve_join(
2370 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2376 $attrs->{group_by} ||= $attrs->{select}
2377 if delete $attrs->{distinct};
2378 if ( $attrs->{order_by} ) {
2379 $attrs->{order_by} = (
2380 ref( $attrs->{order_by} ) eq 'ARRAY'
2381 ? [ @{ $attrs->{order_by} } ]
2382 : [ $attrs->{order_by} ]
2386 $attrs->{order_by} = [];
2389 my $collapse = $attrs->{collapse} || {};
2390 if ( my $prefetch = delete $attrs->{prefetch} ) {
2391 $prefetch = $self->_merge_attr( {}, $prefetch );
2393 my $seen = { %{ $attrs->{seen_join} || {} } };
2394 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2396 # bring joins back to level of current class
2398 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2399 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2400 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2402 push( @{ $attrs->{order_by} }, @pre_order );
2404 $attrs->{collapse} = $collapse;
2406 if ( $attrs->{page} ) {
2407 $attrs->{offset} ||= 0;
2408 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2411 return $self->{_attrs} = $attrs;
2415 my ($self, $attr) = @_;
2417 if (ref $attr eq 'HASH') {
2418 return $self->_rollout_hash($attr);
2419 } elsif (ref $attr eq 'ARRAY') {
2420 return $self->_rollout_array($attr);
2426 sub _rollout_array {
2427 my ($self, $attr) = @_;
2430 foreach my $element (@{$attr}) {
2431 if (ref $element eq 'HASH') {
2432 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2433 } elsif (ref $element eq 'ARRAY') {
2434 # XXX - should probably recurse here
2435 push( @rolled_array, @{$self->_rollout_array($element)} );
2437 push( @rolled_array, $element );
2440 return \@rolled_array;
2444 my ($self, $attr) = @_;
2447 foreach my $key (keys %{$attr}) {
2448 push( @rolled_array, { $key => $attr->{$key} } );
2450 return \@rolled_array;
2453 sub _calculate_score {
2454 my ($self, $a, $b) = @_;
2456 if (ref $b eq 'HASH') {
2457 my ($b_key) = keys %{$b};
2458 if (ref $a eq 'HASH') {
2459 my ($a_key) = keys %{$a};
2460 if ($a_key eq $b_key) {
2461 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2466 return ($a eq $b_key) ? 1 : 0;
2469 if (ref $a eq 'HASH') {
2470 my ($a_key) = keys %{$a};
2471 return ($b eq $a_key) ? 1 : 0;
2473 return ($b eq $a) ? 1 : 0;
2479 my ($self, $orig, $import) = @_;
2481 return $import unless defined($orig);
2482 return $orig unless defined($import);
2484 $orig = $self->_rollout_attr($orig);
2485 $import = $self->_rollout_attr($import);
2488 foreach my $import_element ( @{$import} ) {
2489 # find best candidate from $orig to merge $b_element into
2490 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2491 foreach my $orig_element ( @{$orig} ) {
2492 my $score = $self->_calculate_score( $orig_element, $import_element );
2493 if ($score > $best_candidate->{score}) {
2494 $best_candidate->{position} = $position;
2495 $best_candidate->{score} = $score;
2499 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2501 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2502 push( @{$orig}, $import_element );
2504 my $orig_best = $orig->[$best_candidate->{position}];
2505 # merge orig_best and b_element together and replace original with merged
2506 if (ref $orig_best ne 'HASH') {
2507 $orig->[$best_candidate->{position}] = $import_element;
2508 } elsif (ref $import_element eq 'HASH') {
2509 my ($key) = keys %{$orig_best};
2510 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2513 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2523 $self->_source_handle($_[0]->handle);
2525 $self->_source_handle->resolve;
2529 =head2 throw_exception
2531 See L<DBIx::Class::Schema/throw_exception> for details.
2535 sub throw_exception {
2537 if (ref $self && $self->_source_handle->schema) {
2538 $self->_source_handle->schema->throw_exception(@_)
2545 # XXX: FIXME: Attributes docs need clearing up
2549 Attributes are used to refine a ResultSet in various ways when
2550 searching for data. They can be passed to any method which takes an
2551 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2554 These are in no particular order:
2560 =item Value: ( $order_by | \@order_by | \%order_by )
2564 Which column(s) to order the results by. If a single column name, or
2565 an arrayref of names is supplied, the argument is passed through
2566 directly to SQL. The hashref syntax allows for connection-agnostic
2567 specification of ordering direction:
2569 For descending order:
2571 order_by => { -desc => [qw/col1 col2 col3/] }
2573 For explicit ascending order:
2575 order_by => { -asc => 'col' }
2577 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2578 supported, although you are strongly encouraged to use the hashref
2579 syntax as outlined above.
2585 =item Value: \@columns
2589 Shortcut to request a particular set of columns to be retrieved. Each
2590 column spec may be a string (a table column name), or a hash (in which
2591 case the key is the C<as> value, and the value is used as the C<select>
2592 expression). Adds C<me.> onto the start of any column without a C<.> in
2593 it and sets C<select> from that, then auto-populates C<as> from
2594 C<select> as normal. (You may also use the C<cols> attribute, as in
2595 earlier versions of DBIC.)
2601 =item Value: \@columns
2605 Indicates additional columns to be selected from storage. Works the same
2606 as L</columns> but adds columns to the selection. (You may also use the
2607 C<include_columns> attribute, as in earlier versions of DBIC). For
2610 $schema->resultset('CD')->search(undef, {
2611 '+columns' => ['artist.name'],
2615 would return all CDs and include a 'name' column to the information
2616 passed to object inflation. Note that the 'artist' is the name of the
2617 column (or relationship) accessor, and 'name' is the name of the column
2618 accessor in the related table.
2620 =head2 include_columns
2624 =item Value: \@columns
2628 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2634 =item Value: \@select_columns
2638 Indicates which columns should be selected from the storage. You can use
2639 column names, or in the case of RDBMS back ends, function or stored procedure
2642 $rs = $schema->resultset('Employee')->search(undef, {
2645 { count => 'employeeid' },
2650 When you use function/stored procedure names and do not supply an C<as>
2651 attribute, the column names returned are storage-dependent. E.g. MySQL would
2652 return a column named C<count(employeeid)> in the above example.
2658 Indicates additional columns to be selected from storage. Works the same as
2659 L</select> but adds columns to the selection.
2667 Indicates additional column names for those added via L</+select>. See L</as>.
2675 =item Value: \@inflation_names
2679 Indicates column names for object inflation. That is, C<as>
2680 indicates the name that the column can be accessed as via the
2681 C<get_column> method (or via the object accessor, B<if one already
2682 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2684 The C<as> attribute is used in conjunction with C<select>,
2685 usually when C<select> contains one or more function or stored
2688 $rs = $schema->resultset('Employee')->search(undef, {
2691 { count => 'employeeid' }
2693 as => ['name', 'employee_count'],
2696 my $employee = $rs->first(); # get the first Employee
2698 If the object against which the search is performed already has an accessor
2699 matching a column name specified in C<as>, the value can be retrieved using
2700 the accessor as normal:
2702 my $name = $employee->name();
2704 If on the other hand an accessor does not exist in the object, you need to
2705 use C<get_column> instead:
2707 my $employee_count = $employee->get_column('employee_count');
2709 You can create your own accessors if required - see
2710 L<DBIx::Class::Manual::Cookbook> for details.
2712 Please note: This will NOT insert an C<AS employee_count> into the SQL
2713 statement produced, it is used for internal access only. Thus
2714 attempting to use the accessor in an C<order_by> clause or similar
2715 will fail miserably.
2717 To get around this limitation, you can supply literal SQL to your
2718 C<select> attibute that contains the C<AS alias> text, eg:
2720 select => [\'myfield AS alias']
2726 =item Value: ($rel_name | \@rel_names | \%rel_names)
2730 Contains a list of relationships that should be joined for this query. For
2733 # Get CDs by Nine Inch Nails
2734 my $rs = $schema->resultset('CD')->search(
2735 { 'artist.name' => 'Nine Inch Nails' },
2736 { join => 'artist' }
2739 Can also contain a hash reference to refer to the other relation's relations.
2742 package MyApp::Schema::Track;
2743 use base qw/DBIx::Class/;
2744 __PACKAGE__->table('track');
2745 __PACKAGE__->add_columns(qw/trackid cd position title/);
2746 __PACKAGE__->set_primary_key('trackid');
2747 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2750 # In your application
2751 my $rs = $schema->resultset('Artist')->search(
2752 { 'track.title' => 'Teardrop' },
2754 join => { cd => 'track' },
2755 order_by => 'artist.name',
2759 You need to use the relationship (not the table) name in conditions,
2760 because they are aliased as such. The current table is aliased as "me", so
2761 you need to use me.column_name in order to avoid ambiguity. For example:
2763 # Get CDs from 1984 with a 'Foo' track
2764 my $rs = $schema->resultset('CD')->search(
2767 'tracks.name' => 'Foo'
2769 { join => 'tracks' }
2772 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2773 similarly for a third time). For e.g.
2775 my $rs = $schema->resultset('Artist')->search({
2776 'cds.title' => 'Down to Earth',
2777 'cds_2.title' => 'Popular',
2779 join => [ qw/cds cds/ ],
2782 will return a set of all artists that have both a cd with title 'Down
2783 to Earth' and a cd with title 'Popular'.
2785 If you want to fetch related objects from other tables as well, see C<prefetch>
2788 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2794 =item Value: ($rel_name | \@rel_names | \%rel_names)
2798 Contains one or more relationships that should be fetched along with
2799 the main query (when they are accessed afterwards the data will
2800 already be available, without extra queries to the database). This is
2801 useful for when you know you will need the related objects, because it
2802 saves at least one query:
2804 my $rs = $schema->resultset('Tag')->search(
2813 The initial search results in SQL like the following:
2815 SELECT tag.*, cd.*, artist.* FROM tag
2816 JOIN cd ON tag.cd = cd.cdid
2817 JOIN artist ON cd.artist = artist.artistid
2819 L<DBIx::Class> has no need to go back to the database when we access the
2820 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2823 Simple prefetches will be joined automatically, so there is no need
2824 for a C<join> attribute in the above search.
2826 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2827 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2828 with an accessor type of 'single' or 'filter'). A more complex example that
2829 prefetches an artists cds, the tracks on those cds, and the tags associted
2830 with that artist is given below (assuming many-to-many from artists to tags):
2832 my $rs = $schema->resultset('Artist')->search(
2836 { cds => 'tracks' },
2837 { artist_tags => 'tags' }
2843 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2844 attributes will be ignored.
2854 Makes the resultset paged and specifies the page to retrieve. Effectively
2855 identical to creating a non-pages resultset and then calling ->page($page)
2858 If L<rows> attribute is not specified it defualts to 10 rows per page.
2868 Specifes the maximum number of rows for direct retrieval or the number of
2869 rows per page if the page attribute or method is used.
2875 =item Value: $offset
2879 Specifies the (zero-based) row number for the first row to be returned, or the
2880 of the first row of the first page if paging is used.
2886 =item Value: \@columns
2890 A arrayref of columns to group by. Can include columns of joined tables.
2892 group_by => [qw/ column1 column2 ... /]
2898 =item Value: $condition
2902 HAVING is a select statement attribute that is applied between GROUP BY and
2903 ORDER BY. It is applied to the after the grouping calculations have been
2906 having => { 'count(employee)' => { '>=', 100 } }
2912 =item Value: (0 | 1)
2916 Set to 1 to group by all columns.
2922 Adds to the WHERE clause.
2924 # only return rows WHERE deleted IS NULL for all searches
2925 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2927 Can be overridden by passing C<{ where => undef }> as an attribute
2934 Set to 1 to cache search results. This prevents extra SQL queries if you
2935 revisit rows in your ResultSet:
2937 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2939 while( my $artist = $resultset->next ) {
2943 $rs->first; # without cache, this would issue a query
2945 By default, searches are not cached.
2947 For more examples of using these attributes, see
2948 L<DBIx::Class::Manual::Cookbook>.
2954 =item Value: \@from_clause
2958 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
2959 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
2962 NOTE: Use this on your own risk. This allows you to shoot off your foot!
2964 C<join> will usually do what you need and it is strongly recommended that you
2965 avoid using C<from> unless you cannot achieve the desired result using C<join>.
2966 And we really do mean "cannot", not just tried and failed. Attempting to use
2967 this because you're having problems with C<join> is like trying to use x86
2968 ASM because you've got a syntax error in your C. Trust us on this.
2970 Now, if you're still really, really sure you need to use this (and if you're
2971 not 100% sure, ask the mailing list first), here's an explanation of how this
2974 The syntax is as follows -
2977 { <alias1> => <table1> },
2979 { <alias2> => <table2>, -join_type => 'inner|left|right' },
2980 [], # nested JOIN (optional)
2981 { <table1.column1> => <table2.column2>, ... (more conditions) },
2983 # More of the above [ ] may follow for additional joins
2990 ON <table1.column1> = <table2.column2>
2991 <more joins may follow>
2993 An easy way to follow the examples below is to remember the following:
2995 Anything inside "[]" is a JOIN
2996 Anything inside "{}" is a condition for the enclosing JOIN
2998 The following examples utilize a "person" table in a family tree application.
2999 In order to express parent->child relationships, this table is self-joined:
3001 # Person->belongs_to('father' => 'Person');
3002 # Person->belongs_to('mother' => 'Person');
3004 C<from> can be used to nest joins. Here we return all children with a father,
3005 then search against all mothers of those children:
3007 $rs = $schema->resultset('Person')->search(
3010 alias => 'mother', # alias columns in accordance with "from"
3012 { mother => 'person' },
3015 { child => 'person' },
3017 { father => 'person' },
3018 { 'father.person_id' => 'child.father_id' }
3021 { 'mother.person_id' => 'child.mother_id' }
3028 # SELECT mother.* FROM person mother
3031 # JOIN person father
3032 # ON ( father.person_id = child.father_id )
3034 # ON ( mother.person_id = child.mother_id )
3036 The type of any join can be controlled manually. To search against only people
3037 with a father in the person table, we could explicitly use C<INNER JOIN>:
3039 $rs = $schema->resultset('Person')->search(
3042 alias => 'child', # alias columns in accordance with "from"
3044 { child => 'person' },
3046 { father => 'person', -join_type => 'inner' },
3047 { 'father.id' => 'child.father_id' }
3054 # SELECT child.* FROM person child
3055 # INNER JOIN person father ON child.father_id = father.id
3057 If you need to express really complex joins or you need a subselect, you
3058 can supply literal SQL to C<from> via a scalar reference. In this case
3059 the contents of the scalar will replace the table name asscoiated with the
3062 WARNING: This technique might very well not work as expected on chained
3063 searches - you have been warned.
3065 # Assuming the Event resultsource is defined as:
3067 MySchema::Event->add_columns (
3070 is_auto_increment => 1,
3079 MySchema::Event->set_primary_key ('sequence');
3081 # This will get back the latest event for every location. The column
3082 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3083 # combo to limit the resultset
3085 $rs = $schema->resultset('Event');
3086 $table = $rs->result_source->name;
3087 $latest = $rs->search (
3090 (SELECT e1.* FROM $table e1
3092 ON e1.location = e2.location
3093 AND e1.sequence < e2.sequence
3094 WHERE e2.sequence is NULL
3099 # Equivalent SQL (with the DBIC chunks added):
3101 SELECT me.sequence, me.location, me.type FROM
3102 (SELECT e1.* FROM events e1
3104 ON e1.location = e2.location
3105 AND e1.sequence < e2.sequence
3106 WHERE e2.sequence is NULL
3113 =item Value: ( 'update' | 'shared' )
3117 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT