1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
6 use Carp::Clan qw/^DBIx::Class/;
7 use DBIx::Class::Exception;
10 use DBIx::Class::ResultSetColumn;
11 use DBIx::Class::ResultSourceHandle;
13 use Scalar::Util qw/blessed weaken/;
15 use Storable qw/nfreeze thaw/;
17 # not importing first() as it will clash with our own method
24 # De-duplication in _merge_attr() is disabled, but left in for reference
25 *__HM_DEDUP = sub () { 0 };
33 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
37 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
41 my $users_rs = $schema->resultset('User');
42 while( $user = $users_rs->next) {
43 print $user->username;
46 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
47 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
51 A ResultSet is an object which stores a set of conditions representing
52 a query. It is the backbone of DBIx::Class (i.e. the really
53 important/useful bit).
55 No SQL is executed on the database when a ResultSet is created, it
56 just stores all the conditions needed to create the query.
58 A basic ResultSet representing the data of an entire table is returned
59 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
60 L<Source|DBIx::Class::Manual::Glossary/Source> name.
62 my $users_rs = $schema->resultset('User');
64 A new ResultSet is returned from calling L</search> on an existing
65 ResultSet. The new one will contain all the conditions of the
66 original, plus any new conditions added in the C<search> call.
68 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
69 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
72 The query that the ResultSet represents is B<only> executed against
73 the database when these methods are called:
74 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
76 If a resultset is used in a numeric context it returns the L</count>.
77 However, if it is used in a boolean context it is B<always> true. So if
78 you want to check if a resultset has any results, you must use C<if $rs
83 =head2 Chaining resultsets
85 Let's say you've got a query that needs to be run to return some data
86 to the user. But, you have an authorization system in place that
87 prevents certain users from seeing certain information. So, you want
88 to construct the basic query in one method, but add constraints to it in
93 my $request = $self->get_request; # Get a request object somehow.
94 my $schema = $self->get_schema; # Get the DBIC schema object somehow.
96 my $cd_rs = $schema->resultset('CD')->search({
97 title => $request->param('title'),
98 year => $request->param('year'),
101 $self->apply_security_policy( $cd_rs );
103 return $cd_rs->all();
106 sub apply_security_policy {
115 =head3 Resolving conditions and attributes
117 When a resultset is chained from another resultset, conditions and
118 attributes with the same keys need resolving.
120 L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
121 into the existing ones from the original resultset.
123 The L</where> and L</having> attributes, and any search conditions, are
124 merged with an SQL C<AND> to the existing condition from the original
127 All other attributes are overridden by any new ones supplied in the
130 =head2 Multiple queries
132 Since a resultset just defines a query, you can do all sorts of
133 things with it with the same object.
135 # Don't hit the DB yet.
136 my $cd_rs = $schema->resultset('CD')->search({
137 title => 'something',
141 # Each of these hits the DB individually.
142 my $count = $cd_rs->count;
143 my $most_recent = $cd_rs->get_column('date_released')->max();
144 my @records = $cd_rs->all;
146 And it's not just limited to SELECT statements.
152 $cd_rs->create({ artist => 'Fred' });
154 Which is the same as:
156 $schema->resultset('CD')->create({
157 title => 'something',
162 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
170 =item Arguments: $source, \%$attrs
172 =item Return Value: $rs
176 The resultset constructor. Takes a source object (usually a
177 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
178 L</ATTRIBUTES> below). Does not perform any queries -- these are
179 executed as needed by the other methods.
181 Generally you won't need to construct a resultset manually. You'll
182 automatically get one from e.g. a L</search> called in scalar context:
184 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
186 IMPORTANT: If called on an object, proxies to new_result instead so
188 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
190 will return a CD object, not a ResultSet.
196 return $class->new_result(@_) if ref $class;
198 my ($source, $attrs) = @_;
199 $source = $source->handle
200 unless $source->isa('DBIx::Class::ResultSourceHandle');
201 $attrs = { %{$attrs||{}} };
203 if ($attrs->{page}) {
204 $attrs->{rows} ||= 10;
207 $attrs->{alias} ||= 'me';
209 # Creation of {} and bless separated to mitigate RH perl bug
210 # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
212 _source_handle => $source,
213 cond => $attrs->{where},
221 $attrs->{result_class} || $source->resolve->result_class
231 =item Arguments: $cond, \%attrs?
233 =item Return Value: $resultset (scalar context), @row_objs (list context)
237 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
238 my $new_rs = $cd_rs->search({ year => 2005 });
240 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
241 # year = 2005 OR year = 2004
243 If you need to pass in additional attributes but no additional condition,
244 call it as C<search(undef, \%attrs)>.
246 # "SELECT name, artistid FROM $artist_table"
247 my @all_artists = $schema->resultset('Artist')->search(undef, {
248 columns => [qw/name artistid/],
251 For a list of attributes that can be passed to C<search>, see
252 L</ATTRIBUTES>. For more examples of using this function, see
253 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
254 documentation for the first argument, see L<SQL::Abstract>.
256 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
260 Note that L</search> does not process/deflate any of the values passed in the
261 L<SQL::Abstract>-compatible search condition structure. This is unlike other
262 condition-bound methods L</new>, L</create> and L</find>. The user must ensure
263 manually that any value passed to this method will stringify to something the
264 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
265 objects, for more info see:
266 L<DBIx::Class::Manual::Cookbook/Formatting_DateTime_objects_in_queries>.
272 my $rs = $self->search_rs( @_ );
274 my $want = wantarray;
278 elsif (defined $want) {
282 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense');
290 =item Arguments: $cond, \%attrs?
292 =item Return Value: $resultset
296 This method does the same exact thing as search() except it will
297 always return a resultset, even in list context.
304 # Special-case handling for (undef, undef).
305 if ( @_ == 2 && !defined $_[1] && !defined $_[0] ) {
310 $call_attrs = pop(@_) if (
311 @_ > 1 and ( ! defined $_[-1] or ref $_[-1] eq 'HASH' )
314 # see if we can keep the cache (no $rs changes)
316 my %safe = (alias => 1, cache => 1);
317 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
320 ref $_[0] eq 'HASH' && ! keys %{$_[0]}
322 ref $_[0] eq 'ARRAY' && ! @{$_[0]}
324 $cache = $self->get_cache;
327 my $old_attrs = { %{$self->{attrs}} };
328 my $old_having = delete $old_attrs->{having};
329 my $old_where = delete $old_attrs->{where};
331 # reset the selector list
332 if (List::Util::first { exists $call_attrs->{$_} } qw{columns select as}) {
333 delete @{$old_attrs}{qw{select as columns +select +as +columns include_columns}};
336 my $new_attrs = { %{$old_attrs}, %{$call_attrs} };
338 # merge new attrs into inherited
339 foreach my $key (qw/join prefetch/) {
340 next unless exists $call_attrs->{$key};
341 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key});
343 foreach my $key (qw/+select +as +columns include_columns bind/) {
344 next unless exists $call_attrs->{$key};
345 $new_attrs->{$key} = $self->_merge_attr($old_attrs->{$key}, $call_attrs->{$key});
348 # rip apart the rest of @_, parse a condition
351 if (ref $_[0] eq 'HASH') {
352 (keys %{$_[0]}) ? $_[0] : undef
358 $self->throw_exception('Odd number of arguments to search')
366 carp 'search( %condition ) is deprecated, use search( \%condition ) instead'
367 if (@_ > 1 and ! $self->result_source->result_class->isa('DBIx::Class::CDBICompat') );
369 for ($old_where, $call_cond) {
371 $new_attrs->{where} = $self->_stack_cond (
372 $_, $new_attrs->{where}
377 if (defined $old_having) {
378 $new_attrs->{having} = $self->_stack_cond (
379 $old_having, $new_attrs->{having}
383 my $rs = (ref $self)->new($self->result_source, $new_attrs);
385 $rs->set_cache($cache) if ($cache);
391 my ($self, $left, $right) = @_;
392 if (defined $left xor defined $right) {
393 return defined $left ? $left : $right;
395 elsif (defined $left) {
396 return { -and => [ map
397 { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
405 =head2 search_literal
409 =item Arguments: $sql_fragment, @bind_values
411 =item Return Value: $resultset (scalar context), @row_objs (list context)
415 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
416 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
418 Pass a literal chunk of SQL to be added to the conditional part of the
421 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
422 only be used in that context. C<search_literal> is a convenience method.
423 It is equivalent to calling $schema->search(\[]), but if you want to ensure
424 columns are bound correctly, use C<search>.
426 Example of how to use C<search> instead of C<search_literal>
428 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
429 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
432 See L<DBIx::Class::Manual::Cookbook/Searching> and
433 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
434 require C<search_literal>.
439 my ($self, $sql, @bind) = @_;
441 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
444 return $self->search(\[ $sql, map [ __DUMMY__ => $_ ], @bind ], ($attr || () ));
451 =item Arguments: \%columns_values | @pk_values, \%attrs?
453 =item Return Value: $row_object | undef
457 Finds and returns a single row based on supplied criteria. Takes either a
458 hashref with the same format as L</create> (including inference of foreign
459 keys from related objects), or a list of primary key values in the same
460 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
461 declaration on the L</result_source>.
463 In either case an attempt is made to combine conditions already existing on
464 the resultset with the condition passed to this method.
466 To aid with preparing the correct query for the storage you may supply the
467 C<key> attribute, which is the name of a
468 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
469 unique constraint corresponding to the
470 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
471 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
472 to construct a query that satisfies the named unique constraint fully (
473 non-NULL values for each column member of the constraint) an exception is
476 If no C<key> is specified, the search is carried over all unique constraints
477 which are fully defined by the available condition.
479 If no such constraint is found, C<find> currently defaults to a simple
480 C<< search->(\%column_values) >> which may or may not do what you expect.
481 Note that this fallback behavior may be deprecated in further versions. If
482 you need to search with arbitrary conditions - use L</search>. If the query
483 resulting from this fallback produces more than one row, a warning to the
484 effect is issued, though only the first row is constructed and returned as
487 In addition to C<key>, L</find> recognizes and applies standard
488 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
490 Note that if you have extra concerns about the correctness of the resulting
491 query you need to specify the C<key> attribute and supply the entire condition
492 as an argument to find (since it is not always possible to perform the
493 combination of the resultset condition with the supplied one, especially if
494 the resultset condition contains literal sql).
496 For example, to find a row by its primary key:
498 my $cd = $schema->resultset('CD')->find(5);
500 You can also find a row by a specific unique constraint:
502 my $cd = $schema->resultset('CD')->find(
504 artist => 'Massive Attack',
505 title => 'Mezzanine',
507 { key => 'cd_artist_title' }
510 See also L</find_or_create> and L</update_or_create>.
516 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
518 my $rsrc = $self->result_source;
520 # Parse out the condition from input
522 if (ref $_[0] eq 'HASH') {
523 $call_cond = { %{$_[0]} };
526 my $constraint = exists $attrs->{key} ? $attrs->{key} : 'primary';
527 my @c_cols = $rsrc->unique_constraint_columns($constraint);
529 $self->throw_exception(
530 "No constraint columns, maybe a malformed '$constraint' constraint?"
533 $self->throw_exception (
534 'find() expects either a column/value hashref, or a list of values '
535 . "corresponding to the columns of the specified unique constraint '$constraint'"
536 ) unless @c_cols == @_;
539 @{$call_cond}{@c_cols} = @_;
543 for my $key (keys %$call_cond) {
545 my $keyref = ref($call_cond->{$key})
547 my $relinfo = $rsrc->relationship_info($key)
549 my $val = delete $call_cond->{$key};
551 next if $keyref eq 'ARRAY'; # has_many for multi_create
553 my $rel_q = $rsrc->_resolve_condition(
554 $relinfo->{cond}, $val, $key
556 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
557 @related{keys %$rel_q} = values %$rel_q;
561 # relationship conditions take precedence (?)
562 @{$call_cond}{keys %related} = values %related;
564 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
566 if (exists $attrs->{key}) {
567 $final_cond = $self->_qualify_cond_columns (
569 $self->_build_unique_cond (
577 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
578 # This means that we got here after a merger of relationship conditions
579 # in ::Relationship::Base::search_related (the row method), and furthermore
580 # the relationship is of the 'single' type. This means that the condition
581 # provided by the relationship (already attached to $self) is sufficient,
582 # as there can be only one row in the database that would satisfy the
586 # no key was specified - fall down to heuristics mode:
587 # run through all unique queries registered on the resultset, and
588 # 'OR' all qualifying queries together
589 my (@unique_queries, %seen_column_combinations);
590 for my $c_name ($rsrc->unique_constraint_names) {
591 next if $seen_column_combinations{
592 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
595 push @unique_queries, try {
596 $self->_build_unique_cond ($c_name, $call_cond)
600 $final_cond = @unique_queries
601 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
602 : $self->_non_unique_find_fallback ($call_cond, $attrs)
606 # Run the query, passing the result_class since it should propagate for find
607 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
608 if (keys %{$rs->_resolved_attrs->{collapse}}) {
610 carp "Query returned more than one row" if $rs->next;
618 # This is a stop-gap method as agreed during the discussion on find() cleanup:
619 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
621 # It is invoked when find() is called in legacy-mode with insufficiently-unique
622 # condition. It is provided for overrides until a saner way forward is devised
624 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
625 # the road. Please adjust your tests accordingly to catch this situation early
626 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
628 # The method will not be removed without an adequately complete replacement
629 # for strict-mode enforcement
630 sub _non_unique_find_fallback {
631 my ($self, $cond, $attrs) = @_;
633 return $self->_qualify_cond_columns(
635 exists $attrs->{alias}
637 : $self->{attrs}{alias}
642 sub _qualify_cond_columns {
643 my ($self, $cond, $alias) = @_;
645 my %aliased = %$cond;
646 for (keys %aliased) {
647 $aliased{"$alias.$_"} = delete $aliased{$_}
654 sub _build_unique_cond {
655 my ($self, $constraint_name, $extra_cond) = @_;
657 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
659 # combination may fail if $self->{cond} is non-trivial
660 my ($final_cond) = try {
661 $self->_merge_with_rscond ($extra_cond)
666 # trim out everything not in $columns
667 $final_cond = { map { $_ => $final_cond->{$_} } @c_cols };
669 if (my @missing = grep { ! defined $final_cond->{$_} } (@c_cols) ) {
670 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
672 join (', ', map { "'$_'" } @missing),
679 =head2 search_related
683 =item Arguments: $rel, $cond, \%attrs?
685 =item Return Value: $new_resultset
689 $new_rs = $cd_rs->search_related('artist', {
693 Searches the specified relationship, optionally specifying a condition and
694 attributes for matching records. See L</ATTRIBUTES> for more information.
699 return shift->related_resultset(shift)->search(@_);
702 =head2 search_related_rs
704 This method works exactly the same as search_related, except that
705 it guarantees a resultset, even in list context.
709 sub search_related_rs {
710 return shift->related_resultset(shift)->search_rs(@_);
717 =item Arguments: none
719 =item Return Value: $cursor
723 Returns a storage-driven cursor to the given resultset. See
724 L<DBIx::Class::Cursor> for more information.
731 my $attrs = $self->_resolved_attrs_copy;
733 return $self->{cursor}
734 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
735 $attrs->{where},$attrs);
742 =item Arguments: $cond?
744 =item Return Value: $row_object | undef
748 my $cd = $schema->resultset('CD')->single({ year => 2001 });
750 Inflates the first result without creating a cursor if the resultset has
751 any records in it; if not returns C<undef>. Used by L</find> as a lean version
754 While this method can take an optional search condition (just like L</search>)
755 being a fast-code-path it does not recognize search attributes. If you need to
756 add extra joins or similar, call L</search> and then chain-call L</single> on the
757 L<DBIx::Class::ResultSet> returned.
763 As of 0.08100, this method enforces the assumption that the preceding
764 query returns only one row. If more than one row is returned, you will receive
767 Query returned more than one row
769 In this case, you should be using L</next> or L</find> instead, or if you really
770 know what you are doing, use the L</rows> attribute to explicitly limit the size
773 This method will also throw an exception if it is called on a resultset prefetching
774 has_many, as such a prefetch implies fetching multiple rows from the database in
775 order to assemble the resulting object.
782 my ($self, $where) = @_;
784 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
787 my $attrs = $self->_resolved_attrs_copy;
789 if (keys %{$attrs->{collapse}}) {
790 $self->throw_exception(
791 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
796 if (defined $attrs->{where}) {
799 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
800 $where, delete $attrs->{where} ]
803 $attrs->{where} = $where;
807 my @data = $self->result_source->storage->select_single(
808 $attrs->{from}, $attrs->{select},
809 $attrs->{where}, $attrs
812 return (@data ? ($self->_construct_object(@data))[0] : undef);
818 # Recursively collapse the query, accumulating values for each column.
820 sub _collapse_query {
821 my ($self, $query, $collapsed) = @_;
825 if (ref $query eq 'ARRAY') {
826 foreach my $subquery (@$query) {
827 next unless ref $subquery; # -or
828 $collapsed = $self->_collapse_query($subquery, $collapsed);
831 elsif (ref $query eq 'HASH') {
832 if (keys %$query and (keys %$query)[0] eq '-and') {
833 foreach my $subquery (@{$query->{-and}}) {
834 $collapsed = $self->_collapse_query($subquery, $collapsed);
838 foreach my $col (keys %$query) {
839 my $value = $query->{$col};
840 $collapsed->{$col}{$value}++;
852 =item Arguments: $cond?
854 =item Return Value: $resultsetcolumn
858 my $max_length = $rs->get_column('length')->max;
860 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
865 my ($self, $column) = @_;
866 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
874 =item Arguments: $cond, \%attrs?
876 =item Return Value: $resultset (scalar context), @row_objs (list context)
880 # WHERE title LIKE '%blue%'
881 $cd_rs = $rs->search_like({ title => '%blue%'});
883 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
884 that this is simply a convenience method retained for ex Class::DBI users.
885 You most likely want to use L</search> with specific operators.
887 For more information, see L<DBIx::Class::Manual::Cookbook>.
889 This method is deprecated and will be removed in 0.09. Use L</search()>
890 instead. An example conversion is:
892 ->search_like({ foo => 'bar' });
896 ->search({ foo => { like => 'bar' } });
903 'search_like() is deprecated and will be removed in DBIC version 0.09.'
904 .' Instead use ->search({ x => { -like => "y%" } })'
905 .' (note the outer pair of {}s - they are important!)'
907 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
908 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
909 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
910 return $class->search($query, { %$attrs });
917 =item Arguments: $first, $last
919 =item Return Value: $resultset (scalar context), @row_objs (list context)
923 Returns a resultset or object list representing a subset of elements from the
924 resultset slice is called on. Indexes are from 0, i.e., to get the first
927 my ($one, $two, $three) = $rs->slice(0, 2);
932 my ($self, $min, $max) = @_;
933 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
934 $attrs->{offset} = $self->{attrs}{offset} || 0;
935 $attrs->{offset} += $min;
936 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
937 return $self->search(undef, $attrs);
938 #my $slice = (ref $self)->new($self->result_source, $attrs);
939 #return (wantarray ? $slice->all : $slice);
946 =item Arguments: none
948 =item Return Value: $result | undef
952 Returns the next element in the resultset (C<undef> is there is none).
954 Can be used to efficiently iterate over records in the resultset:
956 my $rs = $schema->resultset('CD')->search;
957 while (my $cd = $rs->next) {
961 Note that you need to store the resultset object, and call C<next> on it.
962 Calling C<< resultset('Table')->next >> repeatedly will always return the
963 first record from the resultset.
969 if (my $cache = $self->get_cache) {
970 $self->{all_cache_position} ||= 0;
971 return $cache->[$self->{all_cache_position}++];
973 if ($self->{attrs}{cache}) {
974 delete $self->{pager};
975 $self->{all_cache_position} = 1;
976 return ($self->all)[0];
978 if ($self->{stashed_objects}) {
979 my $obj = shift(@{$self->{stashed_objects}});
980 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
984 exists $self->{stashed_row}
985 ? @{delete $self->{stashed_row}}
986 : $self->cursor->next
988 return undef unless (@row);
989 my ($row, @more) = $self->_construct_object(@row);
990 $self->{stashed_objects} = \@more if @more;
994 sub _construct_object {
995 my ($self, @row) = @_;
997 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row)
999 my @new = $self->result_class->inflate_result($self->result_source, @$info);
1000 @new = $self->{_attrs}{record_filter}->(@new)
1001 if exists $self->{_attrs}{record_filter};
1005 sub _collapse_result {
1006 my ($self, $as_proto, $row) = @_;
1010 # 'foo' => [ undef, 'foo' ]
1011 # 'foo.bar' => [ 'foo', 'bar' ]
1012 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
1014 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
1016 my %collapse = %{$self->{_attrs}{collapse}||{}};
1020 # if we're doing collapsing (has_many prefetch) we need to grab records
1021 # until the PK changes, so fill @pri_index. if not, we leave it empty so
1022 # we know we don't have to bother.
1024 # the reason for not using the collapse stuff directly is because if you
1025 # had for e.g. two artists in a row with no cds, the collapse info for
1026 # both would be NULL (undef) so you'd lose the second artist
1028 # store just the index so we can check the array positions from the row
1029 # without having to contruct the full hash
1031 if (keys %collapse) {
1032 my %pri = map { ($_ => 1) } $self->result_source->_pri_cols;
1033 foreach my $i (0 .. $#construct_as) {
1034 next if defined($construct_as[$i][0]); # only self table
1035 if (delete $pri{$construct_as[$i][1]}) {
1036 push(@pri_index, $i);
1038 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1042 # no need to do an if, it'll be empty if @pri_index is empty anyway
1044 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1048 do { # no need to check anything at the front, we always want the first row
1052 foreach my $this_as (@construct_as) {
1053 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1056 push(@const_rows, \%const);
1058 } until ( # no pri_index => no collapse => drop straight out
1061 do { # get another row, stash it, drop out if different PK
1063 @copy = $self->cursor->next;
1064 $self->{stashed_row} = \@copy;
1066 # last thing in do block, counts as true if anything doesn't match
1068 # check xor defined first for NULL vs. NOT NULL then if one is
1069 # defined the other must be so check string equality
1072 (defined $pri_vals{$_} ^ defined $copy[$_])
1073 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1078 my $alias = $self->{attrs}{alias};
1085 foreach my $const (@const_rows) {
1086 scalar @const_keys or do {
1087 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1089 foreach my $key (@const_keys) {
1092 my @parts = split(/\./, $key);
1094 my $data = $const->{$key};
1095 foreach my $p (@parts) {
1096 $target = $target->[1]->{$p} ||= [];
1098 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1099 # collapsing at this point and on final part
1100 my $pos = $collapse_pos{$cur};
1101 CK: foreach my $ck (@ckey) {
1102 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1103 $collapse_pos{$cur} = $data;
1104 delete @collapse_pos{ # clear all positioning for sub-entries
1105 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1112 if (exists $collapse{$cur}) {
1113 $target = $target->[-1];
1116 $target->[0] = $data;
1118 $info->[0] = $const->{$key};
1126 =head2 result_source
1130 =item Arguments: $result_source?
1132 =item Return Value: $result_source
1136 An accessor for the primary ResultSource object from which this ResultSet
1143 =item Arguments: $result_class?
1145 =item Return Value: $result_class
1149 An accessor for the class to use when creating row objects. Defaults to
1150 C<< result_source->result_class >> - which in most cases is the name of the
1151 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1153 Note that changing the result_class will also remove any components
1154 that were originally loaded in the source class via
1155 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1156 in the original source class will not run.
1161 my ($self, $result_class) = @_;
1162 if ($result_class) {
1163 unless (ref $result_class) { # don't fire this for an object
1164 $self->ensure_class_loaded($result_class);
1166 $self->_result_class($result_class);
1167 # THIS LINE WOULD BE A BUG - this accessor specifically exists to
1168 # permit the user to set result class on one result set only; it only
1169 # chains if provided to search()
1170 #$self->{attrs}{result_class} = $result_class if ref $self;
1172 $self->_result_class;
1179 =item Arguments: $cond, \%attrs??
1181 =item Return Value: $count
1185 Performs an SQL C<COUNT> with the same query as the resultset was built
1186 with to find the number of elements. Passing arguments is equivalent to
1187 C<< $rs->search ($cond, \%attrs)->count >>
1193 return $self->search(@_)->count if @_ and defined $_[0];
1194 return scalar @{ $self->get_cache } if $self->get_cache;
1196 my $attrs = $self->_resolved_attrs_copy;
1198 # this is a little optimization - it is faster to do the limit
1199 # adjustments in software, instead of a subquery
1200 my $rows = delete $attrs->{rows};
1201 my $offset = delete $attrs->{offset};
1204 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1205 $crs = $self->_count_subq_rs ($attrs);
1208 $crs = $self->_count_rs ($attrs);
1210 my $count = $crs->next;
1212 $count -= $offset if $offset;
1213 $count = $rows if $rows and $rows < $count;
1214 $count = 0 if ($count < 0);
1223 =item Arguments: $cond, \%attrs??
1225 =item Return Value: $count_rs
1229 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1230 This can be very handy for subqueries:
1232 ->search( { amount => $some_rs->count_rs->as_query } )
1234 As with regular resultsets the SQL query will be executed only after
1235 the resultset is accessed via L</next> or L</all>. That would return
1236 the same single value obtainable via L</count>.
1242 return $self->search(@_)->count_rs if @_;
1244 # this may look like a lack of abstraction (count() does about the same)
1245 # but in fact an _rs *must* use a subquery for the limits, as the
1246 # software based limiting can not be ported if this $rs is to be used
1247 # in a subquery itself (i.e. ->as_query)
1248 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1249 return $self->_count_subq_rs;
1252 return $self->_count_rs;
1257 # returns a ResultSetColumn object tied to the count query
1260 my ($self, $attrs) = @_;
1262 my $rsrc = $self->result_source;
1263 $attrs ||= $self->_resolved_attrs;
1265 my $tmp_attrs = { %$attrs };
1266 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1267 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1269 # overwrite the selector (supplied by the storage)
1270 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1271 $tmp_attrs->{as} = 'count';
1273 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1279 # same as above but uses a subquery
1281 sub _count_subq_rs {
1282 my ($self, $attrs) = @_;
1284 my $rsrc = $self->result_source;
1285 $attrs ||= $self->_resolved_attrs;
1287 my $sub_attrs = { %$attrs };
1288 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1289 delete @{$sub_attrs}{qw/collapse select _prefetch_select as order_by for/};
1291 # if we multi-prefetch we group_by primary keys only as this is what we would
1292 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1293 if ( keys %{$attrs->{collapse}} ) {
1294 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->_pri_cols) ]
1297 # Calculate subquery selector
1298 if (my $g = $sub_attrs->{group_by}) {
1300 my $sql_maker = $rsrc->storage->sql_maker;
1302 # necessary as the group_by may refer to aliased functions
1304 for my $sel (@{$attrs->{select}}) {
1305 $sel_index->{$sel->{-as}} = $sel
1306 if (ref $sel eq 'HASH' and $sel->{-as});
1309 for my $g_part (@$g) {
1310 my $colpiece = $sel_index->{$g_part} || $g_part;
1312 # disqualify join-based group_by's. Arcane but possible query
1313 # also horrible horrible hack to alias a column (not a func.)
1314 # (probably need to introduce SQLA syntax)
1315 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1318 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1320 push @{$sub_attrs->{select}}, $colpiece;
1324 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1325 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1328 return $rsrc->resultset_class
1329 ->new ($rsrc, $sub_attrs)
1331 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1332 ->get_column ('count');
1339 =head2 count_literal
1343 =item Arguments: $sql_fragment, @bind_values
1345 =item Return Value: $count
1349 Counts the results in a literal query. Equivalent to calling L</search_literal>
1350 with the passed arguments, then L</count>.
1354 sub count_literal { shift->search_literal(@_)->count; }
1360 =item Arguments: none
1362 =item Return Value: @objects
1366 Returns all elements in the resultset. Called implicitly if the resultset
1367 is returned in list context.
1374 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1377 return @{ $self->get_cache } if $self->get_cache;
1381 if (keys %{$self->_resolved_attrs->{collapse}}) {
1382 # Using $self->cursor->all is really just an optimisation.
1383 # If we're collapsing has_many prefetches it probably makes
1384 # very little difference, and this is cleaner than hacking
1385 # _construct_object to survive the approach
1386 $self->cursor->reset;
1387 my @row = $self->cursor->next;
1389 push(@obj, $self->_construct_object(@row));
1390 @row = (exists $self->{stashed_row}
1391 ? @{delete $self->{stashed_row}}
1392 : $self->cursor->next);
1395 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1398 $self->set_cache(\@obj) if $self->{attrs}{cache};
1407 =item Arguments: none
1409 =item Return Value: $self
1413 Resets the resultset's cursor, so you can iterate through the elements again.
1414 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1421 delete $self->{_attrs} if exists $self->{_attrs};
1422 $self->{all_cache_position} = 0;
1423 $self->cursor->reset;
1431 =item Arguments: none
1433 =item Return Value: $object | undef
1437 Resets the resultset and returns an object for the first result (or C<undef>
1438 if the resultset is empty).
1443 return $_[0]->reset->next;
1449 # Determines whether and what type of subquery is required for the $rs operation.
1450 # If grouping is necessary either supplies its own, or verifies the current one
1451 # After all is done delegates to the proper storage method.
1453 sub _rs_update_delete {
1454 my ($self, $op, $values) = @_;
1456 my $rsrc = $self->result_source;
1458 # if a condition exists we need to strip all table qualifiers
1459 # if this is not possible we'll force a subquery below
1460 my $cond = $rsrc->schema->storage->_strip_cond_qualifiers ($self->{cond});
1462 my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/);
1463 my $needs_subq = $needs_group_by_subq || (not defined $cond) || $self->_has_resolved_attr(qw/rows offset/);
1465 if ($needs_group_by_subq or $needs_subq) {
1467 # make a new $rs selecting only the PKs (that's all we really need)
1468 my $attrs = $self->_resolved_attrs_copy;
1471 delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_select as/;
1472 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ];
1474 if ($needs_group_by_subq) {
1475 # make sure no group_by was supplied, or if there is one - make sure it matches
1476 # the columns compiled above perfectly. Anything else can not be sanely executed
1477 # on most databases so croak right then and there
1479 if (my $g = $attrs->{group_by}) {
1480 my @current_group_by = map
1481 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1486 join ("\x00", sort @current_group_by)
1488 join ("\x00", sort @{$attrs->{columns}} )
1490 $self->throw_exception (
1491 "You have just attempted a $op operation on a resultset which does group_by"
1492 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1493 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1494 . ' kind of queries. Please retry the operation with a modified group_by or'
1495 . ' without using one at all.'
1500 $attrs->{group_by} = $attrs->{columns};
1504 my $subrs = (ref $self)->new($rsrc, $attrs);
1505 return $self->result_source->storage->_subq_update_delete($subrs, $op, $values);
1508 return $rsrc->storage->$op(
1510 $op eq 'update' ? $values : (),
1520 =item Arguments: \%values
1522 =item Return Value: $storage_rv
1526 Sets the specified columns in the resultset to the supplied values in a
1527 single query. Note that this will not run any accessor/set_column/update
1528 triggers, nor will it update any row object instances derived from this
1529 resultset (this includes the contents of the L<resultset cache|/set_cache>
1530 if any). See L</update_all> if you need to execute any on-update
1531 triggers or cascades defined either by you or a
1532 L<result component|DBIx::Class::Manual::Component/WHAT_IS_A_COMPONENT>.
1534 The return value is a pass through of what the underlying
1535 storage backend returned, and may vary. See L<DBI/execute> for the most
1540 Note that L</update> does not process/deflate any of the values passed in.
1541 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1542 ensure manually that any value passed to this method will stringify to
1543 something the RDBMS knows how to deal with. A notable example is the
1544 handling of L<DateTime> objects, for more info see:
1545 L<DBIx::Class::Manual::Cookbook/Formatting_DateTime_objects_in_queries>.
1550 my ($self, $values) = @_;
1551 $self->throw_exception('Values for update must be a hash')
1552 unless ref $values eq 'HASH';
1554 return $self->_rs_update_delete ('update', $values);
1561 =item Arguments: \%values
1563 =item Return Value: 1
1567 Fetches all objects and updates them one at a time via
1568 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
1569 triggers, while L</update> will not.
1574 my ($self, $values) = @_;
1575 $self->throw_exception('Values for update_all must be a hash')
1576 unless ref $values eq 'HASH';
1578 my $guard = $self->result_source->schema->txn_scope_guard;
1579 $_->update($values) for $self->all;
1588 =item Arguments: none
1590 =item Return Value: $storage_rv
1594 Deletes the rows matching this resultset in a single query. Note that this
1595 will not run any delete triggers, nor will it alter the
1596 L<in_storage|DBIx::Class::Row/in_storage> status of any row object instances
1597 derived from this resultset (this includes the contents of the
1598 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
1599 execute any on-delete triggers or cascades defined either by you or a
1600 L<result component|DBIx::Class::Manual::Component/WHAT_IS_A_COMPONENT>.
1602 The return value is a pass through of what the underlying storage backend
1603 returned, and may vary. See L<DBI/execute> for the most common case.
1609 $self->throw_exception('delete does not accept any arguments')
1612 return $self->_rs_update_delete ('delete');
1619 =item Arguments: none
1621 =item Return Value: 1
1625 Fetches all objects and deletes them one at a time via
1626 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
1627 triggers, while L</delete> will not.
1633 $self->throw_exception('delete_all does not accept any arguments')
1636 my $guard = $self->result_source->schema->txn_scope_guard;
1637 $_->delete for $self->all;
1646 =item Arguments: \@data;
1650 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1651 For the arrayref of hashrefs style each hashref should be a structure suitable
1652 forsubmitting to a $resultset->create(...) method.
1654 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1655 to insert the data, as this is a faster method.
1657 Otherwise, each set of data is inserted into the database using
1658 L<DBIx::Class::ResultSet/create>, and the resulting objects are
1659 accumulated into an array. The array itself, or an array reference
1660 is returned depending on scalar or list context.
1662 Example: Assuming an Artist Class that has many CDs Classes relating:
1664 my $Artist_rs = $schema->resultset("Artist");
1666 ## Void Context Example
1667 $Artist_rs->populate([
1668 { artistid => 4, name => 'Manufactured Crap', cds => [
1669 { title => 'My First CD', year => 2006 },
1670 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1673 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1674 { title => 'My parents sold me to a record company', year => 2005 },
1675 { title => 'Why Am I So Ugly?', year => 2006 },
1676 { title => 'I Got Surgery and am now Popular', year => 2007 }
1681 ## Array Context Example
1682 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1683 { name => "Artist One"},
1684 { name => "Artist Two"},
1685 { name => "Artist Three", cds=> [
1686 { title => "First CD", year => 2007},
1687 { title => "Second CD", year => 2008},
1691 print $ArtistOne->name; ## response is 'Artist One'
1692 print $ArtistThree->cds->count ## reponse is '2'
1694 For the arrayref of arrayrefs style, the first element should be a list of the
1695 fieldsnames to which the remaining elements are rows being inserted. For
1698 $Arstist_rs->populate([
1699 [qw/artistid name/],
1700 [100, 'A Formally Unknown Singer'],
1701 [101, 'A singer that jumped the shark two albums ago'],
1702 [102, 'An actually cool singer'],
1705 Please note an important effect on your data when choosing between void and
1706 wantarray context. Since void context goes straight to C<insert_bulk> in
1707 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1708 C<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1709 create primary keys for you, you will find that your PKs are empty. In this
1710 case you will have to use the wantarray context in order to create those
1718 # cruft placed in standalone method
1719 my $data = $self->_normalize_populate_args(@_);
1721 if(defined wantarray) {
1723 foreach my $item (@$data) {
1724 push(@created, $self->create($item));
1726 return wantarray ? @created : \@created;
1728 my $first = $data->[0];
1730 # if a column is a registered relationship, and is a non-blessed hash/array, consider
1731 # it relationship data
1732 my (@rels, @columns);
1733 for (keys %$first) {
1734 my $ref = ref $first->{$_};
1735 $self->result_source->has_relationship($_) && ($ref eq 'ARRAY' or $ref eq 'HASH')
1741 my @pks = $self->result_source->primary_columns;
1743 ## do the belongs_to relationships
1744 foreach my $index (0..$#$data) {
1746 # delegate to create() for any dataset without primary keys with specified relationships
1747 if (grep { !defined $data->[$index]->{$_} } @pks ) {
1749 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
1750 my @ret = $self->populate($data);
1756 foreach my $rel (@rels) {
1757 next unless ref $data->[$index]->{$rel} eq "HASH";
1758 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1759 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1760 my $related = $result->result_source->_resolve_condition(
1761 $result->result_source->relationship_info($reverse)->{cond},
1766 delete $data->[$index]->{$rel};
1767 $data->[$index] = {%{$data->[$index]}, %$related};
1769 push @columns, keys %$related if $index == 0;
1773 ## inherit the data locked in the conditions of the resultset
1774 my ($rs_data) = $self->_merge_with_rscond({});
1775 delete @{$rs_data}{@columns};
1776 my @inherit_cols = keys %$rs_data;
1777 my @inherit_data = values %$rs_data;
1779 ## do bulk insert on current row
1780 $self->result_source->storage->insert_bulk(
1781 $self->result_source,
1782 [@columns, @inherit_cols],
1783 [ map { [ @$_{@columns}, @inherit_data ] } @$data ],
1786 ## do the has_many relationships
1787 foreach my $item (@$data) {
1789 foreach my $rel (@rels) {
1790 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1792 my $parent = $self->find({map { $_ => $item->{$_} } @pks})
1793 || $self->throw_exception('Cannot find the relating object.');
1795 my $child = $parent->$rel;
1797 my $related = $child->result_source->_resolve_condition(
1798 $parent->result_source->relationship_info($rel)->{cond},
1803 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1804 my @populate = map { {%$_, %$related} } @rows_to_add;
1806 $child->populate( \@populate );
1813 # populate() argumnets went over several incarnations
1814 # What we ultimately support is AoH
1815 sub _normalize_populate_args {
1816 my ($self, $arg) = @_;
1818 if (ref $arg eq 'ARRAY') {
1819 if (ref $arg->[0] eq 'HASH') {
1822 elsif (ref $arg->[0] eq 'ARRAY') {
1824 my @colnames = @{$arg->[0]};
1825 foreach my $values (@{$arg}[1 .. $#$arg]) {
1826 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
1832 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
1839 =item Arguments: none
1841 =item Return Value: $pager
1845 Return Value a L<Data::Page> object for the current resultset. Only makes
1846 sense for queries with a C<page> attribute.
1848 To get the full count of entries for a paged resultset, call
1849 C<total_entries> on the L<Data::Page> object.
1853 # make a wizard good for both a scalar and a hashref
1854 my $mk_lazy_count_wizard = sub {
1855 require Variable::Magic;
1857 my $stash = { total_rs => shift };
1858 my $slot = shift; # only used by the hashref magic
1860 my $magic = Variable::Magic::wizard (
1861 data => sub { $stash },
1867 # set value lazily, and dispell for good
1868 ${$_[0]} = $_[1]{total_rs}->count;
1869 Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref});
1873 # an explicit set implies dispell as well
1874 # the unless() is to work around "fun and giggles" below
1875 Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref})
1876 unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
1883 if ($_[2] eq $slot and !$_[1]{inactive}) {
1884 my $cnt = $_[1]{total_rs}->count;
1885 $_[0]->{$slot} = $cnt;
1887 # attempting to dispell in a fetch handle (works in store), seems
1888 # to invariable segfault on 5.10, 5.12, 5.13 :(
1889 # so use an inactivator instead
1890 #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
1896 if (! $_[1]{inactive} and $_[2] eq $slot) {
1897 #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
1899 unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
1906 $stash->{magic_selfref} = $magic;
1907 weaken ($stash->{magic_selfref}); # this fails on 5.8.1
1912 # the tie class for 5.8.1
1914 package # hide from pause
1915 DBIx::Class::__DBIC_LAZY_RS_COUNT__;
1916 use base qw/Tie::Hash/;
1918 sub FIRSTKEY { my $dummy = scalar keys %{$_[0]{data}}; each %{$_[0]{data}} }
1919 sub NEXTKEY { each %{$_[0]{data}} }
1920 sub EXISTS { exists $_[0]{data}{$_[1]} }
1921 sub DELETE { delete $_[0]{data}{$_[1]} }
1922 sub CLEAR { %{$_[0]{data}} = () }
1923 sub SCALAR { scalar %{$_[0]{data}} }
1926 $_[1]{data} = {%{$_[1]{selfref}}};
1927 %{$_[1]{selfref}} = ();
1928 Scalar::Util::weaken ($_[1]{selfref});
1929 return bless ($_[1], $_[0]);
1933 if ($_[1] eq $_[0]{slot}) {
1934 my $cnt = $_[0]{data}{$_[1]} = $_[0]{total_rs}->count;
1935 untie %{$_[0]{selfref}};
1936 %{$_[0]{selfref}} = %{$_[0]{data}};
1945 $_[0]{data}{$_[1]} = $_[2];
1946 if ($_[1] eq $_[0]{slot}) {
1947 untie %{$_[0]{selfref}};
1948 %{$_[0]{selfref}} = %{$_[0]{data}};
1957 return $self->{pager} if $self->{pager};
1959 if ($self->get_cache) {
1960 $self->throw_exception ('Pagers on cached resultsets are not supported');
1963 my $attrs = $self->{attrs};
1964 if (!defined $attrs->{page}) {
1965 $self->throw_exception("Can't create pager for non-paged rs");
1967 elsif ($attrs->{page} <= 0) {
1968 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
1970 $attrs->{rows} ||= 10;
1972 # throw away the paging flags and re-run the count (possibly
1973 # with a subselect) to get the real total count
1974 my $count_attrs = { %$attrs };
1975 delete $count_attrs->{$_} for qw/rows offset page pager/;
1976 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
1979 ### the following may seem awkward and dirty, but it's a thought-experiment
1980 ### necessary for future development of DBIx::DS. Do *NOT* change this code
1981 ### before talking to ribasushi/mst
1983 my $pager = Data::Page->new(
1984 0, #start with an empty set
1986 $self->{attrs}{page},
1989 my $data_slot = 'total_entries';
1991 # Since we are interested in a cached value (once it's set - it's set), every
1992 # technique will detach from the magic-host once the time comes to fire the
1993 # ->count (or in the segfaulting case of >= 5.10 it will deactivate itself)
1995 if ($] < 5.008003) {
1996 # 5.8.1 throws 'Modification of a read-only value attempted' when one tries
1997 # to weakref the magic container :(
1999 tie (%$pager, 'DBIx::Class::__DBIC_LAZY_RS_COUNT__',
2000 { slot => $data_slot, total_rs => $total_rs, selfref => $pager }
2003 elsif ($] < 5.010) {
2004 # We can use magic on the hash value slot. It's interesting that the magic is
2005 # attached to the hash-slot, and does *not* stop working once I do the dummy
2006 # assignments after the cast()
2007 # tested on 5.8.3 and 5.8.9
2008 my $magic = $mk_lazy_count_wizard->($total_rs);
2009 Variable::Magic::cast ( $pager->{$data_slot}, $magic );
2011 # this is for fun and giggles
2012 $pager->{$data_slot} = -1;
2013 $pager->{$data_slot} = 0;
2015 # this does not work for scalars, but works with
2017 #my %vals = %$pager;
2022 # And the uvar magic
2023 # works on 5.10.1, 5.12.1 and 5.13.4 in its current form,
2024 # however see the wizard maker for more notes
2025 my $magic = $mk_lazy_count_wizard->($total_rs, $data_slot);
2026 Variable::Magic::cast ( %$pager, $magic );
2029 $pager->{$data_slot} = -1;
2030 $pager->{$data_slot} = 0;
2038 return $self->{pager} = $pager;
2045 =item Arguments: $page_number
2047 =item Return Value: $rs
2051 Returns a resultset for the $page_number page of the resultset on which page
2052 is called, where each page contains a number of rows equal to the 'rows'
2053 attribute set on the resultset (10 by default).
2058 my ($self, $page) = @_;
2059 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2066 =item Arguments: \%vals
2068 =item Return Value: $rowobject
2072 Creates a new row object in the resultset's result class and returns
2073 it. The row is not inserted into the database at this point, call
2074 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2075 will tell you whether the row object has been inserted or not.
2077 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2082 my ($self, $values) = @_;
2083 $self->throw_exception( "new_result needs a hash" )
2084 unless (ref $values eq 'HASH');
2086 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2090 @$cols_from_relations
2091 ? (-cols_from_relations => $cols_from_relations)
2093 -source_handle => $self->_source_handle,
2094 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2097 return $self->result_class->new(\%new);
2100 # _merge_with_rscond
2102 # Takes a simple hash of K/V data and returns its copy merged with the
2103 # condition already present on the resultset. Additionally returns an
2104 # arrayref of value/condition names, which were inferred from related
2105 # objects (this is needed for in-memory related objects)
2106 sub _merge_with_rscond {
2107 my ($self, $data) = @_;
2109 my (%new_data, @cols_from_relations);
2111 my $alias = $self->{attrs}{alias};
2113 if (! defined $self->{cond}) {
2114 # just massage $data below
2116 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2117 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2118 @cols_from_relations = keys %new_data;
2120 elsif (ref $self->{cond} ne 'HASH') {
2121 $self->throw_exception(
2122 "Can't abstract implicit construct, resultset condition not a hash"
2126 # precendence must be given to passed values over values inherited from
2127 # the cond, so the order here is important.
2128 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2129 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2131 while ( my($col, $value) = each %implied ) {
2132 my $vref = ref $value;
2133 if ($vref eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '=') {
2134 $new_data{$col} = $value->{'='};
2136 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2137 $new_data{$col} = $value;
2144 %{ $self->_remove_alias($data, $alias) },
2147 return (\%new_data, \@cols_from_relations);
2150 # _has_resolved_attr
2152 # determines if the resultset defines at least one
2153 # of the attributes supplied
2155 # used to determine if a subquery is neccessary
2157 # supports some virtual attributes:
2159 # This will scan for any joins being present on the resultset.
2160 # It is not a mere key-search but a deep inspection of {from}
2163 sub _has_resolved_attr {
2164 my ($self, @attr_names) = @_;
2166 my $attrs = $self->_resolved_attrs;
2170 for my $n (@attr_names) {
2171 if (grep { $n eq $_ } (qw/-join/) ) {
2172 $extra_checks{$n}++;
2176 my $attr = $attrs->{$n};
2178 next if not defined $attr;
2180 if (ref $attr eq 'HASH') {
2181 return 1 if keys %$attr;
2183 elsif (ref $attr eq 'ARRAY') {
2191 # a resolved join is expressed as a multi-level from
2193 $extra_checks{-join}
2195 ref $attrs->{from} eq 'ARRAY'
2197 @{$attrs->{from}} > 1
2205 # Recursively collapse the condition.
2207 sub _collapse_cond {
2208 my ($self, $cond, $collapsed) = @_;
2212 if (ref $cond eq 'ARRAY') {
2213 foreach my $subcond (@$cond) {
2214 next unless ref $subcond; # -or
2215 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2218 elsif (ref $cond eq 'HASH') {
2219 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2220 foreach my $subcond (@{$cond->{-and}}) {
2221 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2225 foreach my $col (keys %$cond) {
2226 my $value = $cond->{$col};
2227 $collapsed->{$col} = $value;
2237 # Remove the specified alias from the specified query hash. A copy is made so
2238 # the original query is not modified.
2241 my ($self, $query, $alias) = @_;
2243 my %orig = %{ $query || {} };
2246 foreach my $key (keys %orig) {
2248 $unaliased{$key} = $orig{$key};
2251 $unaliased{$1} = $orig{$key}
2252 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2262 =item Arguments: none
2264 =item Return Value: \[ $sql, @bind ]
2268 Returns the SQL query and bind vars associated with the invocant.
2270 This is generally used as the RHS for a subquery.
2277 my $attrs = $self->_resolved_attrs_copy;
2282 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2283 # $sql also has no wrapping parenthesis in list ctx
2285 my $sqlbind = $self->result_source->storage
2286 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2295 =item Arguments: \%vals, \%attrs?
2297 =item Return Value: $rowobject
2301 my $artist = $schema->resultset('Artist')->find_or_new(
2302 { artist => 'fred' }, { key => 'artists' });
2304 $cd->cd_to_producer->find_or_new({ producer => $producer },
2305 { key => 'primary });
2307 Find an existing record from this resultset using L</find>. if none exists,
2308 instantiate a new result object and return it. The object will not be saved
2309 into your storage until you call L<DBIx::Class::Row/insert> on it.
2311 You most likely want this method when looking for existing rows using a unique
2312 constraint that is not the primary key, or looking for related rows.
2314 If you want objects to be saved immediately, use L</find_or_create> instead.
2316 B<Note>: Make sure to read the documentation of L</find> and understand the
2317 significance of the C<key> attribute, as its lack may skew your search, and
2318 subsequently result in spurious new objects.
2320 B<Note>: Take care when using C<find_or_new> with a table having
2321 columns with default values that you intend to be automatically
2322 supplied by the database (e.g. an auto_increment primary key column).
2323 In normal usage, the value of such columns should NOT be included at
2324 all in the call to C<find_or_new>, even when set to C<undef>.
2330 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2331 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2332 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2335 return $self->new_result($hash);
2342 =item Arguments: \%vals
2344 =item Return Value: a L<DBIx::Class::Row> $object
2348 Attempt to create a single new row or a row with multiple related rows
2349 in the table represented by the resultset (and related tables). This
2350 will not check for duplicate rows before inserting, use
2351 L</find_or_create> to do that.
2353 To create one row for this resultset, pass a hashref of key/value
2354 pairs representing the columns of the table and the values you wish to
2355 store. If the appropriate relationships are set up, foreign key fields
2356 can also be passed an object representing the foreign row, and the
2357 value will be set to its primary key.
2359 To create related objects, pass a hashref of related-object column values
2360 B<keyed on the relationship name>. If the relationship is of type C<multi>
2361 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2362 The process will correctly identify columns holding foreign keys, and will
2363 transparently populate them from the keys of the corresponding relation.
2364 This can be applied recursively, and will work correctly for a structure
2365 with an arbitrary depth and width, as long as the relationships actually
2366 exists and the correct column data has been supplied.
2369 Instead of hashrefs of plain related data (key/value pairs), you may
2370 also pass new or inserted objects. New objects (not inserted yet, see
2371 L</new>), will be inserted into their appropriate tables.
2373 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
2375 Example of creating a new row.
2377 $person_rs->create({
2378 name=>"Some Person",
2379 email=>"somebody@someplace.com"
2382 Example of creating a new row and also creating rows in a related C<has_many>
2383 or C<has_one> resultset. Note Arrayref.
2386 { artistid => 4, name => 'Manufactured Crap', cds => [
2387 { title => 'My First CD', year => 2006 },
2388 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2393 Example of creating a new row and also creating a row in a related
2394 C<belongs_to> resultset. Note Hashref.
2397 title=>"Music for Silly Walks",
2400 name=>"Silly Musician",
2408 When subclassing ResultSet never attempt to override this method. Since
2409 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2410 lot of the internals simply never call it, so your override will be
2411 bypassed more often than not. Override either L<new|DBIx::Class::Row/new>
2412 or L<insert|DBIx::Class::Row/insert> depending on how early in the
2413 L</create> process you need to intervene.
2420 my ($self, $attrs) = @_;
2421 $self->throw_exception( "create needs a hashref" )
2422 unless ref $attrs eq 'HASH';
2423 return $self->new_result($attrs)->insert;
2426 =head2 find_or_create
2430 =item Arguments: \%vals, \%attrs?
2432 =item Return Value: $rowobject
2436 $cd->cd_to_producer->find_or_create({ producer => $producer },
2437 { key => 'primary' });
2439 Tries to find a record based on its primary key or unique constraints; if none
2440 is found, creates one and returns that instead.
2442 my $cd = $schema->resultset('CD')->find_or_create({
2444 artist => 'Massive Attack',
2445 title => 'Mezzanine',
2449 Also takes an optional C<key> attribute, to search by a specific key or unique
2450 constraint. For example:
2452 my $cd = $schema->resultset('CD')->find_or_create(
2454 artist => 'Massive Attack',
2455 title => 'Mezzanine',
2457 { key => 'cd_artist_title' }
2460 B<Note>: Make sure to read the documentation of L</find> and understand the
2461 significance of the C<key> attribute, as its lack may skew your search, and
2462 subsequently result in spurious row creation.
2464 B<Note>: Because find_or_create() reads from the database and then
2465 possibly inserts based on the result, this method is subject to a race
2466 condition. Another process could create a record in the table after
2467 the find has completed and before the create has started. To avoid
2468 this problem, use find_or_create() inside a transaction.
2470 B<Note>: Take care when using C<find_or_create> with a table having
2471 columns with default values that you intend to be automatically
2472 supplied by the database (e.g. an auto_increment primary key column).
2473 In normal usage, the value of such columns should NOT be included at
2474 all in the call to C<find_or_create>, even when set to C<undef>.
2476 See also L</find> and L</update_or_create>. For information on how to declare
2477 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2481 sub find_or_create {
2483 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2484 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2485 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2488 return $self->create($hash);
2491 =head2 update_or_create
2495 =item Arguments: \%col_values, { key => $unique_constraint }?
2497 =item Return Value: $row_object
2501 $resultset->update_or_create({ col => $val, ... });
2503 Like L</find_or_create>, but if a row is found it is immediately updated via
2504 C<< $found_row->update (\%col_values) >>.
2507 Takes an optional C<key> attribute to search on a specific unique constraint.
2510 # In your application
2511 my $cd = $schema->resultset('CD')->update_or_create(
2513 artist => 'Massive Attack',
2514 title => 'Mezzanine',
2517 { key => 'cd_artist_title' }
2520 $cd->cd_to_producer->update_or_create({
2521 producer => $producer,
2527 B<Note>: Make sure to read the documentation of L</find> and understand the
2528 significance of the C<key> attribute, as its lack may skew your search, and
2529 subsequently result in spurious row creation.
2531 B<Note>: Take care when using C<update_or_create> with a table having
2532 columns with default values that you intend to be automatically
2533 supplied by the database (e.g. an auto_increment primary key column).
2534 In normal usage, the value of such columns should NOT be included at
2535 all in the call to C<update_or_create>, even when set to C<undef>.
2537 See also L</find> and L</find_or_create>. For information on how to declare
2538 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2542 sub update_or_create {
2544 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2545 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2547 my $row = $self->find($cond, $attrs);
2549 $row->update($cond);
2553 return $self->create($cond);
2556 =head2 update_or_new
2560 =item Arguments: \%col_values, { key => $unique_constraint }?
2562 =item Return Value: $rowobject
2566 $resultset->update_or_new({ col => $val, ... });
2568 Like L</find_or_new> but if a row is found it is immediately updated via
2569 C<< $found_row->update (\%col_values) >>.
2573 # In your application
2574 my $cd = $schema->resultset('CD')->update_or_new(
2576 artist => 'Massive Attack',
2577 title => 'Mezzanine',
2580 { key => 'cd_artist_title' }
2583 if ($cd->in_storage) {
2584 # the cd was updated
2587 # the cd is not yet in the database, let's insert it
2591 B<Note>: Make sure to read the documentation of L</find> and understand the
2592 significance of the C<key> attribute, as its lack may skew your search, and
2593 subsequently result in spurious new objects.
2595 B<Note>: Take care when using C<update_or_new> with a table having
2596 columns with default values that you intend to be automatically
2597 supplied by the database (e.g. an auto_increment primary key column).
2598 In normal usage, the value of such columns should NOT be included at
2599 all in the call to C<update_or_new>, even when set to C<undef>.
2601 See also L</find>, L</find_or_create> and L</find_or_new>.
2607 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2608 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2610 my $row = $self->find( $cond, $attrs );
2611 if ( defined $row ) {
2612 $row->update($cond);
2616 return $self->new_result($cond);
2623 =item Arguments: none
2625 =item Return Value: \@cache_objects | undef
2629 Gets the contents of the cache for the resultset, if the cache is set.
2631 The cache is populated either by using the L</prefetch> attribute to
2632 L</search> or by calling L</set_cache>.
2644 =item Arguments: \@cache_objects
2646 =item Return Value: \@cache_objects
2650 Sets the contents of the cache for the resultset. Expects an arrayref
2651 of objects of the same class as those produced by the resultset. Note that
2652 if the cache is set the resultset will return the cached objects rather
2653 than re-querying the database even if the cache attr is not set.
2655 The contents of the cache can also be populated by using the
2656 L</prefetch> attribute to L</search>.
2661 my ( $self, $data ) = @_;
2662 $self->throw_exception("set_cache requires an arrayref")
2663 if defined($data) && (ref $data ne 'ARRAY');
2664 $self->{all_cache} = $data;
2671 =item Arguments: none
2673 =item Return Value: undef
2677 Clears the cache for the resultset.
2682 shift->set_cache(undef);
2689 =item Arguments: none
2691 =item Return Value: true, if the resultset has been paginated
2699 return !!$self->{attrs}{page};
2706 =item Arguments: none
2708 =item Return Value: true, if the resultset has been ordered with C<order_by>.
2716 return scalar $self->result_source->storage->_extract_order_columns($self->{attrs}{order_by});
2719 =head2 related_resultset
2723 =item Arguments: $relationship_name
2725 =item Return Value: $resultset
2729 Returns a related resultset for the supplied relationship name.
2731 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2735 sub related_resultset {
2736 my ($self, $rel) = @_;
2738 $self->{related_resultsets} ||= {};
2739 return $self->{related_resultsets}{$rel} ||= do {
2740 my $rsrc = $self->result_source;
2741 my $rel_info = $rsrc->relationship_info($rel);
2743 $self->throw_exception(
2744 "search_related: result source '" . $rsrc->source_name .
2745 "' has no such relationship $rel")
2748 my $attrs = $self->_chain_relationship($rel);
2750 my $join_count = $attrs->{seen_join}{$rel};
2752 my $alias = $self->result_source->storage
2753 ->relname_to_table_alias($rel, $join_count);
2755 # since this is search_related, and we already slid the select window inwards
2756 # (the select/as attrs were deleted in the beginning), we need to flip all
2757 # left joins to inner, so we get the expected results
2758 # read the comment on top of the actual function to see what this does
2759 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
2762 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2763 delete @{$attrs}{qw(result_class alias)};
2767 if (my $cache = $self->get_cache) {
2768 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2769 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2774 my $rel_source = $rsrc->related_source($rel);
2778 # The reason we do this now instead of passing the alias to the
2779 # search_rs below is that if you wrap/overload resultset on the
2780 # source you need to know what alias it's -going- to have for things
2781 # to work sanely (e.g. RestrictWithObject wants to be able to add
2782 # extra query restrictions, and these may need to be $alias.)
2784 my $rel_attrs = $rel_source->resultset_attributes;
2785 local $rel_attrs->{alias} = $alias;
2787 $rel_source->resultset
2791 where => $attrs->{where},
2794 $new->set_cache($new_cache) if $new_cache;
2799 =head2 current_source_alias
2803 =item Arguments: none
2805 =item Return Value: $source_alias
2809 Returns the current table alias for the result source this resultset is built
2810 on, that will be used in the SQL query. Usually it is C<me>.
2812 Currently the source alias that refers to the result set returned by a
2813 L</search>/L</find> family method depends on how you got to the resultset: it's
2814 C<me> by default, but eg. L</search_related> aliases it to the related result
2815 source name (and keeps C<me> referring to the original result set). The long
2816 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2817 (and make this method unnecessary).
2819 Thus it's currently necessary to use this method in predefined queries (see
2820 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2821 source alias of the current result set:
2823 # in a result set class
2825 my ($self, $user) = @_;
2827 my $me = $self->current_source_alias;
2829 return $self->search(
2830 "$me.modified" => $user->id,
2836 sub current_source_alias {
2839 return ($self->{attrs} || {})->{alias} || 'me';
2842 =head2 as_subselect_rs
2846 =item Arguments: none
2848 =item Return Value: $resultset
2852 Act as a barrier to SQL symbols. The resultset provided will be made into a
2853 "virtual view" by including it as a subquery within the from clause. From this
2854 point on, any joined tables are inaccessible to ->search on the resultset (as if
2855 it were simply where-filtered without joins). For example:
2857 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
2859 # 'x' now pollutes the query namespace
2861 # So the following works as expected
2862 my $ok_rs = $rs->search({'x.other' => 1});
2864 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
2865 # def) we look for one row with contradictory terms and join in another table
2866 # (aliased 'x_2') which we never use
2867 my $broken_rs = $rs->search({'x.name' => 'def'});
2869 my $rs2 = $rs->as_subselect_rs;
2871 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
2872 my $not_joined_rs = $rs2->search({'x.other' => 1});
2874 # works as expected: finds a 'table' row related to two x rows (abc and def)
2875 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
2877 Another example of when one might use this would be to select a subset of
2878 columns in a group by clause:
2880 my $rs = $schema->resultset('Bar')->search(undef, {
2881 group_by => [qw{ id foo_id baz_id }],
2882 })->as_subselect_rs->search(undef, {
2883 columns => [qw{ id foo_id }]
2886 In the above example normally columns would have to be equal to the group by,
2887 but because we isolated the group by into a subselect the above works.
2891 sub as_subselect_rs {
2894 my $attrs = $self->_resolved_attrs;
2896 my $fresh_rs = (ref $self)->new (
2897 $self->result_source
2900 # these pieces will be locked in the subquery
2901 delete $fresh_rs->{cond};
2902 delete @{$fresh_rs->{attrs}}{qw/where bind/};
2904 return $fresh_rs->search( {}, {
2906 $attrs->{alias} => $self->as_query,
2907 -alias => $attrs->{alias},
2908 -source_handle => $self->result_source->handle,
2910 alias => $attrs->{alias},
2914 # This code is called by search_related, and makes sure there
2915 # is clear separation between the joins before, during, and
2916 # after the relationship. This information is needed later
2917 # in order to properly resolve prefetch aliases (any alias
2918 # with a relation_chain_depth less than the depth of the
2919 # current prefetch is not considered)
2921 # The increments happen twice per join. An even number means a
2922 # relationship specified via a search_related, whereas an odd
2923 # number indicates a join/prefetch added via attributes
2925 # Also this code will wrap the current resultset (the one we
2926 # chain to) in a subselect IFF it contains limiting attributes
2927 sub _chain_relationship {
2928 my ($self, $rel) = @_;
2929 my $source = $self->result_source;
2930 my $attrs = { %{$self->{attrs}||{}} };
2932 # we need to take the prefetch the attrs into account before we
2933 # ->_resolve_join as otherwise they get lost - captainL
2934 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
2936 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
2938 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
2941 my @force_subq_attrs = qw/offset rows group_by having/;
2944 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
2946 $self->_has_resolved_attr (@force_subq_attrs)
2948 # Nuke the prefetch (if any) before the new $rs attrs
2949 # are resolved (prefetch is useless - we are wrapping
2950 # a subquery anyway).
2951 my $rs_copy = $self->search;
2952 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
2953 $rs_copy->{attrs}{join},
2954 delete $rs_copy->{attrs}{prefetch},
2958 -source_handle => $source->handle,
2959 -alias => $attrs->{alias},
2960 $attrs->{alias} => $rs_copy->as_query,
2962 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
2963 $seen->{-relation_chain_depth} = 0;
2965 elsif ($attrs->{from}) { #shallow copy suffices
2966 $from = [ @{$attrs->{from}} ];
2970 -source_handle => $source->handle,
2971 -alias => $attrs->{alias},
2972 $attrs->{alias} => $source->from,
2976 my $jpath = ($seen->{-relation_chain_depth})
2977 ? $from->[-1][0]{-join_path}
2980 my @requested_joins = $source->_resolve_join(
2987 push @$from, @requested_joins;
2989 $seen->{-relation_chain_depth}++;
2991 # if $self already had a join/prefetch specified on it, the requested
2992 # $rel might very well be already included. What we do in this case
2993 # is effectively a no-op (except that we bump up the chain_depth on
2994 # the join in question so we could tell it *is* the search_related)
2997 # we consider the last one thus reverse
2998 for my $j (reverse @requested_joins) {
2999 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3000 if ($rel eq $last_j) {
3001 $j->[0]{-relation_chain_depth}++;
3007 unless ($already_joined) {
3008 push @$from, $source->_resolve_join(
3016 $seen->{-relation_chain_depth}++;
3018 return {%$attrs, from => $from, seen_join => $seen};
3021 # too many times we have to do $attrs = { %{$self->_resolved_attrs} }
3022 sub _resolved_attrs_copy {
3024 return { %{$self->_resolved_attrs (@_)} };
3027 sub _resolved_attrs {
3029 return $self->{_attrs} if $self->{_attrs};
3031 my $attrs = { %{ $self->{attrs} || {} } };
3032 my $source = $self->result_source;
3033 my $alias = $attrs->{alias};
3036 # resolve selectors, this one is quite hairy
3038 my $selection_pieces;
3040 $attrs->{columns} ||= delete $attrs->{cols}
3041 if exists $attrs->{cols};
3043 # disassemble columns / +columns
3045 $selection_pieces->{columns}{select},
3046 $selection_pieces->{columns}{as},
3047 $selection_pieces->{'+columns'}{select},
3048 $selection_pieces->{'+columns'}{as},
3053 for my $colbit (@$_) {
3055 if (ref $colbit eq 'HASH') {
3056 for my $as (keys %$colbit) {
3057 push @sel, $colbit->{$as};
3070 (ref $attrs->{columns} eq 'ARRAY' ? delete $attrs->{columns} : [ delete $attrs->{columns} ]),
3071 # include_columns is a legacy add-on to +columns
3072 [ map { ref $_ eq 'ARRAY' ? @$_ : ($_ || () ) } delete @{$attrs}{qw/+columns include_columns/} ] )
3075 # make copies of select/as and +select/+as
3077 $selection_pieces->{'select/as'}{select},
3078 $selection_pieces->{'select/as'}{as},
3079 $selection_pieces->{'+select/+as'}{select},
3080 $selection_pieces->{'+select/+as'}{as},
3082 { $_ ? [ ref $_ eq 'ARRAY' ? @$_ : $_ ] : [] }
3083 ( delete @{$attrs}{qw/select as +select +as/} )
3086 # default to * only when neither no non-plus selectors are available
3088 ! @{$selection_pieces->{'select/as'}{select}}
3090 ! @{$selection_pieces->{'columns'}{select}}
3092 for ($source->columns) {
3093 push @{$selection_pieces->{'select/as'}{select}}, $_;
3094 push @{$selection_pieces->{'select/as'}{as}}, $_;
3098 # final composition order (important)
3099 my @sel_pairs = grep {
3100 $selection_pieces->{$_}
3103 ( $selection_pieces->{$_}{select} && @{$selection_pieces->{$_}{select}} )
3105 ( $selection_pieces->{$_}{as} && @{$selection_pieces->{$_}{as}} )
3107 } qw|columns select/as +columns +select/+as|;
3109 # fill in missing as bits for each pair
3110 # if it's the last pair we can let things slide ( bare +select is sadly popular)
3113 for my $i (0 .. $#sel_pairs) {
3115 my $pairname = $sel_pairs[$i];
3117 my ($sel, $as) = @{$selection_pieces->{$pairname}}{qw/select as/};
3119 $self->throw_exception(
3120 "Unable to assemble final selection list: $pairname specified in addition to unbalanced $sel_pairs[$i-1]"
3121 ) if ($out_of_sync);
3123 if (@$sel == @$as) {
3126 elsif (@$sel < @$as) {
3127 $self->throw_exception(
3128 "More 'as' elements than 'select' elements for $pairname, unable to continue"
3132 # try to deduce the 'as' part, will work only if all the selectors are "plain", or contain an explicit -as
3133 # if we can not deduce something - stop right there and leave the rest of the selector un-as'ed
3134 # if there is an extra selection pair coming after that - it will die due to out_of_sync being set
3135 for my $j ($#$as+1 .. $#$sel) {
3136 if (my $ref = ref $sel->[$j]) {
3137 if ($ref eq 'HASH' and exists $sel->[$j]{-as}) {
3138 push @$as, $sel->[$j]{-as};
3146 push @$as, $sel->[$j];
3152 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3153 # disqualify all $alias.col as-bits (collapser mandated)
3154 for (values %$selection_pieces) {
3155 $_->{select} = [ map { (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" } @{$_->{select}} ];
3156 $_->{as} = [ map { $_ =~ /^\Q$alias.\E(.+)$/ ? $1 : $_ } @{$_->{as}} ];
3161 $attrs->{select} = $self->_merge_attr ($attrs->{select}, $selection_pieces->{$_}{select});
3162 $attrs->{as} = $self->_merge_attr ($attrs->{as}, $selection_pieces->{$_}{as});
3165 # de-duplicate the result (remove *identical* select/as pairs)
3166 # and also die on duplicate {as} pointing to different {select}s
3167 # not using a c-style for as the condition is prone to shrinkage
3170 while ($i <= $#{$attrs->{as}} ) {
3171 my ($sel, $as) = map { $attrs->{$_}[$i] } (qw/select as/);
3173 if ($seen->{"$sel \x00\x00 $as"}++) {
3175 for @{$attrs}{qw/select as/};
3177 elsif ($seen->{$as}++) {
3178 $self->throw_exception(
3179 "inflate_result() alias '$as' specified twice with different SQL-side {select}-ors"
3187 ## selector resolution done
3191 $attrs->{from} ||= [{
3192 -source_handle => $source->handle,
3193 -alias => $self->{attrs}{alias},
3194 $self->{attrs}{alias} => $source->from,
3197 if ( $attrs->{join} || $attrs->{prefetch} ) {
3199 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3200 if ref $attrs->{from} ne 'ARRAY';
3202 my $join = delete $attrs->{join} || {};
3204 if ( defined $attrs->{prefetch} ) {
3205 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3208 $attrs->{from} = # have to copy here to avoid corrupting the original
3210 @{ $attrs->{from} },
3211 $source->_resolve_join(
3214 { %{ $attrs->{seen_join} || {} } },
3215 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3216 ? $attrs->{from}[-1][0]{-join_path}
3223 if ( defined $attrs->{order_by} ) {
3224 $attrs->{order_by} = (
3225 ref( $attrs->{order_by} ) eq 'ARRAY'
3226 ? [ @{ $attrs->{order_by} } ]
3227 : [ $attrs->{order_by} || () ]
3231 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3232 $attrs->{group_by} = [ $attrs->{group_by} ];
3235 # generate the distinct induced group_by early, as prefetch will be carried via a
3236 # subquery (since a group_by is present)
3237 if (delete $attrs->{distinct}) {
3238 if ($attrs->{group_by}) {
3239 carp ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3242 $attrs->{group_by} = $source->storage->_group_over_selection (
3243 @{$attrs}{qw/from select order_by/}
3248 $attrs->{collapse} ||= {};
3249 if ( my $prefetch = delete $attrs->{prefetch} ) {
3250 $prefetch = $self->_merge_joinpref_attr( {}, $prefetch );
3252 my $prefetch_ordering = [];
3254 # this is a separate structure (we don't look in {from} directly)
3255 # as the resolver needs to shift things off the lists to work
3256 # properly (identical-prefetches on different branches)
3258 if (ref $attrs->{from} eq 'ARRAY') {
3260 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3262 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3263 next unless $j->[0]{-alias};
3264 next unless $j->[0]{-join_path};
3265 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3267 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3270 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3271 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3276 $source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
3278 # we need to somehow mark which columns came from prefetch
3279 $attrs->{_prefetch_select} = [ map { $_->[0] } @prefetch ];
3281 push @{ $attrs->{select} }, @{$attrs->{_prefetch_select}};
3282 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3284 push( @{$attrs->{order_by}}, @$prefetch_ordering );
3285 $attrs->{_collapse_order_by} = \@$prefetch_ordering;
3288 # if both page and offset are specified, produce a combined offset
3289 # even though it doesn't make much sense, this is what pre 081xx has
3291 if (my $page = delete $attrs->{page}) {
3293 ($attrs->{rows} * ($page - 1))
3295 ($attrs->{offset} || 0)
3299 return $self->{_attrs} = $attrs;
3303 my ($self, $attr) = @_;
3305 if (ref $attr eq 'HASH') {
3306 return $self->_rollout_hash($attr);
3307 } elsif (ref $attr eq 'ARRAY') {
3308 return $self->_rollout_array($attr);
3314 sub _rollout_array {
3315 my ($self, $attr) = @_;
3318 foreach my $element (@{$attr}) {
3319 if (ref $element eq 'HASH') {
3320 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3321 } elsif (ref $element eq 'ARRAY') {
3322 # XXX - should probably recurse here
3323 push( @rolled_array, @{$self->_rollout_array($element)} );
3325 push( @rolled_array, $element );
3328 return \@rolled_array;
3332 my ($self, $attr) = @_;
3335 foreach my $key (keys %{$attr}) {
3336 push( @rolled_array, { $key => $attr->{$key} } );
3338 return \@rolled_array;
3341 sub _calculate_score {
3342 my ($self, $a, $b) = @_;
3344 if (defined $a xor defined $b) {
3347 elsif (not defined $a) {
3351 if (ref $b eq 'HASH') {
3352 my ($b_key) = keys %{$b};
3353 if (ref $a eq 'HASH') {
3354 my ($a_key) = keys %{$a};
3355 if ($a_key eq $b_key) {
3356 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3361 return ($a eq $b_key) ? 1 : 0;
3364 if (ref $a eq 'HASH') {
3365 my ($a_key) = keys %{$a};
3366 return ($b eq $a_key) ? 1 : 0;
3368 return ($b eq $a) ? 1 : 0;
3373 sub _merge_joinpref_attr {
3374 my ($self, $orig, $import) = @_;
3376 return $import unless defined($orig);
3377 return $orig unless defined($import);
3379 $orig = $self->_rollout_attr($orig);
3380 $import = $self->_rollout_attr($import);
3383 foreach my $import_element ( @{$import} ) {
3384 # find best candidate from $orig to merge $b_element into
3385 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3386 foreach my $orig_element ( @{$orig} ) {
3387 my $score = $self->_calculate_score( $orig_element, $import_element );
3388 if ($score > $best_candidate->{score}) {
3389 $best_candidate->{position} = $position;
3390 $best_candidate->{score} = $score;
3394 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3396 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3397 push( @{$orig}, $import_element );
3399 my $orig_best = $orig->[$best_candidate->{position}];
3400 # merge orig_best and b_element together and replace original with merged
3401 if (ref $orig_best ne 'HASH') {
3402 $orig->[$best_candidate->{position}] = $import_element;
3403 } elsif (ref $import_element eq 'HASH') {
3404 my ($key) = keys %{$orig_best};
3405 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3408 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3419 my $hm = Hash::Merge->new;
3421 $hm->specify_behavior({
3424 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3426 if ($defl xor $defr) {
3427 return $defl ? $_[0] : $_[1];
3432 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3436 return [$_[0], $_[1]];
3440 return $_[1] if !defined $_[0];
3441 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3442 return [$_[0], @{$_[1]}]
3445 return $_[1] if !defined $_[0];
3446 return $_[0] if !keys %{$_[1]};
3447 return [$_[0], $_[1]]
3452 return $_[0] if !defined $_[1];
3453 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3454 return [@{$_[0]}, $_[1]]
3457 my @ret = @{$_[0]} or return $_[1];
3458 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3459 my %idx = map { $_ => 1 } @ret;
3460 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3464 return [ $_[1] ] if ! @{$_[0]};
3465 return $_[0] if !keys %{$_[1]};
3466 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3467 return [ @{$_[0]}, $_[1] ];
3472 return $_[0] if !defined $_[1];
3473 return $_[1] if !keys %{$_[0]};
3474 return [$_[0], $_[1]]
3477 return $_[0] if !@{$_[1]};
3478 return $_[1] if !keys %{$_[0]};
3479 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3480 return [ $_[0], @{$_[1]} ];
3483 return $_[0] if !keys %{$_[1]};
3484 return $_[1] if !keys %{$_[0]};
3485 return $_[0] if $_[0] eq $_[1];
3486 return [ $_[0], $_[1] ];
3489 } => 'DBIC_RS_ATTR_MERGER');
3493 return $hm->merge ($_[1], $_[2]);
3501 $self->_source_handle($_[0]->handle);
3503 $self->_source_handle->resolve;
3508 sub STORABLE_freeze {
3509 my ($self, $cloning) = @_;
3510 my $to_serialize = { %$self };
3512 # A cursor in progress can't be serialized (and would make little sense anyway)
3513 delete $to_serialize->{cursor};
3515 return nfreeze($to_serialize);
3518 # need this hook for symmetry
3520 my ($self, $cloning, $serialized) = @_;
3522 %$self = %{ thaw($serialized) };
3528 =head2 throw_exception
3530 See L<DBIx::Class::Schema/throw_exception> for details.
3534 sub throw_exception {
3537 if (ref $self && $self->_source_handle->schema) {
3538 $self->_source_handle->schema->throw_exception(@_)
3541 DBIx::Class::Exception->throw(@_);
3545 # XXX: FIXME: Attributes docs need clearing up
3549 Attributes are used to refine a ResultSet in various ways when
3550 searching for data. They can be passed to any method which takes an
3551 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3554 These are in no particular order:
3560 =item Value: ( $order_by | \@order_by | \%order_by )
3564 Which column(s) to order the results by.
3566 [The full list of suitable values is documented in
3567 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3570 If a single column name, or an arrayref of names is supplied, the
3571 argument is passed through directly to SQL. The hashref syntax allows
3572 for connection-agnostic specification of ordering direction:
3574 For descending order:
3576 order_by => { -desc => [qw/col1 col2 col3/] }
3578 For explicit ascending order:
3580 order_by => { -asc => 'col' }
3582 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3583 supported, although you are strongly encouraged to use the hashref
3584 syntax as outlined above.
3590 =item Value: \@columns
3594 Shortcut to request a particular set of columns to be retrieved. Each
3595 column spec may be a string (a table column name), or a hash (in which
3596 case the key is the C<as> value, and the value is used as the C<select>
3597 expression). Adds C<me.> onto the start of any column without a C<.> in
3598 it and sets C<select> from that, then auto-populates C<as> from
3599 C<select> as normal. (You may also use the C<cols> attribute, as in
3600 earlier versions of DBIC.)
3602 Essentially C<columns> does the same as L</select> and L</as>.
3604 columns => [ 'foo', { bar => 'baz' } ]
3608 select => [qw/foo baz/],
3615 =item Value: \@columns
3619 Indicates additional columns to be selected from storage. Works the same
3620 as L</columns> but adds columns to the selection. (You may also use the
3621 C<include_columns> attribute, as in earlier versions of DBIC). For
3624 $schema->resultset('CD')->search(undef, {
3625 '+columns' => ['artist.name'],
3629 would return all CDs and include a 'name' column to the information
3630 passed to object inflation. Note that the 'artist' is the name of the
3631 column (or relationship) accessor, and 'name' is the name of the column
3632 accessor in the related table.
3634 =head2 include_columns
3638 =item Value: \@columns
3642 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3648 =item Value: \@select_columns
3652 Indicates which columns should be selected from the storage. You can use
3653 column names, or in the case of RDBMS back ends, function or stored procedure
3656 $rs = $schema->resultset('Employee')->search(undef, {
3659 { count => 'employeeid' },
3660 { max => { length => 'name' }, -as => 'longest_name' }
3665 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3667 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3668 use L</select>, to instruct DBIx::Class how to store the result of the column.
3669 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3670 identifier aliasing. You can however alias a function, so you can use it in
3671 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3672 attribute> supplied as shown in the example above.
3678 Indicates additional columns to be selected from storage. Works the same as
3679 L</select> but adds columns to the default selection, instead of specifying
3688 Indicates additional column names for those added via L</+select>. See L</as>.
3696 =item Value: \@inflation_names
3700 Indicates column names for object inflation. That is L</as> indicates the
3701 slot name in which the column value will be stored within the
3702 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
3703 identifier by the C<get_column> method (or via the object accessor B<if one
3704 with the same name already exists>) as shown below. The L</as> attribute has
3705 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
3707 $rs = $schema->resultset('Employee')->search(undef, {
3710 { count => 'employeeid' },
3711 { max => { length => 'name' }, -as => 'longest_name' }
3720 If the object against which the search is performed already has an accessor
3721 matching a column name specified in C<as>, the value can be retrieved using
3722 the accessor as normal:
3724 my $name = $employee->name();
3726 If on the other hand an accessor does not exist in the object, you need to
3727 use C<get_column> instead:
3729 my $employee_count = $employee->get_column('employee_count');
3731 You can create your own accessors if required - see
3732 L<DBIx::Class::Manual::Cookbook> for details.
3738 =item Value: ($rel_name | \@rel_names | \%rel_names)
3742 Contains a list of relationships that should be joined for this query. For
3745 # Get CDs by Nine Inch Nails
3746 my $rs = $schema->resultset('CD')->search(
3747 { 'artist.name' => 'Nine Inch Nails' },
3748 { join => 'artist' }
3751 Can also contain a hash reference to refer to the other relation's relations.
3754 package MyApp::Schema::Track;
3755 use base qw/DBIx::Class/;
3756 __PACKAGE__->table('track');
3757 __PACKAGE__->add_columns(qw/trackid cd position title/);
3758 __PACKAGE__->set_primary_key('trackid');
3759 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
3762 # In your application
3763 my $rs = $schema->resultset('Artist')->search(
3764 { 'track.title' => 'Teardrop' },
3766 join => { cd => 'track' },
3767 order_by => 'artist.name',
3771 You need to use the relationship (not the table) name in conditions,
3772 because they are aliased as such. The current table is aliased as "me", so
3773 you need to use me.column_name in order to avoid ambiguity. For example:
3775 # Get CDs from 1984 with a 'Foo' track
3776 my $rs = $schema->resultset('CD')->search(
3779 'tracks.name' => 'Foo'
3781 { join => 'tracks' }
3784 If the same join is supplied twice, it will be aliased to <rel>_2 (and
3785 similarly for a third time). For e.g.
3787 my $rs = $schema->resultset('Artist')->search({
3788 'cds.title' => 'Down to Earth',
3789 'cds_2.title' => 'Popular',
3791 join => [ qw/cds cds/ ],
3794 will return a set of all artists that have both a cd with title 'Down
3795 to Earth' and a cd with title 'Popular'.
3797 If you want to fetch related objects from other tables as well, see C<prefetch>
3800 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
3806 =item Value: ($rel_name | \@rel_names | \%rel_names)
3810 Contains one or more relationships that should be fetched along with
3811 the main query (when they are accessed afterwards the data will
3812 already be available, without extra queries to the database). This is
3813 useful for when you know you will need the related objects, because it
3814 saves at least one query:
3816 my $rs = $schema->resultset('Tag')->search(
3825 The initial search results in SQL like the following:
3827 SELECT tag.*, cd.*, artist.* FROM tag
3828 JOIN cd ON tag.cd = cd.cdid
3829 JOIN artist ON cd.artist = artist.artistid
3831 L<DBIx::Class> has no need to go back to the database when we access the
3832 C<cd> or C<artist> relationships, which saves us two SQL statements in this
3835 Simple prefetches will be joined automatically, so there is no need
3836 for a C<join> attribute in the above search.
3838 C<prefetch> can be used with the following relationship types: C<belongs_to>,
3839 C<has_one> (or if you're using C<add_relationship>, any relationship declared
3840 with an accessor type of 'single' or 'filter'). A more complex example that
3841 prefetches an artists cds, the tracks on those cds, and the tags associated
3842 with that artist is given below (assuming many-to-many from artists to tags):
3844 my $rs = $schema->resultset('Artist')->search(
3848 { cds => 'tracks' },
3849 { artist_tags => 'tags' }
3855 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
3856 attributes will be ignored.
3858 B<CAVEATs>: Prefetch does a lot of deep magic. As such, it may not behave
3859 exactly as you might expect.
3865 Prefetch uses the L</cache> to populate the prefetched relationships. This
3866 may or may not be what you want.
3870 If you specify a condition on a prefetched relationship, ONLY those
3871 rows that match the prefetched condition will be fetched into that relationship.
3872 This means that adding prefetch to a search() B<may alter> what is returned by
3873 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
3875 my $artist_rs = $schema->resultset('Artist')->search({
3881 my $count = $artist_rs->first->cds->count;
3883 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
3885 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
3887 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
3889 that cmp_ok() may or may not pass depending on the datasets involved. This
3890 behavior may or may not survive the 0.09 transition.
3902 Makes the resultset paged and specifies the page to retrieve. Effectively
3903 identical to creating a non-pages resultset and then calling ->page($page)
3906 If L<rows> attribute is not specified it defaults to 10 rows per page.
3908 When you have a paged resultset, L</count> will only return the number
3909 of rows in the page. To get the total, use the L</pager> and call
3910 C<total_entries> on it.
3920 Specifies the maximum number of rows for direct retrieval or the number of
3921 rows per page if the page attribute or method is used.
3927 =item Value: $offset
3931 Specifies the (zero-based) row number for the first row to be returned, or the
3932 of the first row of the first page if paging is used.
3938 =item Value: \@columns
3942 A arrayref of columns to group by. Can include columns of joined tables.
3944 group_by => [qw/ column1 column2 ... /]
3950 =item Value: $condition
3954 HAVING is a select statement attribute that is applied between GROUP BY and
3955 ORDER BY. It is applied to the after the grouping calculations have been
3958 having => { 'count(employee)' => { '>=', 100 } }
3964 =item Value: (0 | 1)
3968 Set to 1 to group by all columns. If the resultset already has a group_by
3969 attribute, this setting is ignored and an appropriate warning is issued.
3975 Adds to the WHERE clause.
3977 # only return rows WHERE deleted IS NULL for all searches
3978 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3980 Can be overridden by passing C<< { where => undef } >> as an attribute
3987 Set to 1 to cache search results. This prevents extra SQL queries if you
3988 revisit rows in your ResultSet:
3990 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3992 while( my $artist = $resultset->next ) {
3996 $rs->first; # without cache, this would issue a query
3998 By default, searches are not cached.
4000 For more examples of using these attributes, see
4001 L<DBIx::Class::Manual::Cookbook>.
4007 =item Value: ( 'update' | 'shared' )
4011 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT