1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::ResultSetColumn;
8 use Scalar::Util qw/blessed weaken reftype/;
10 use Data::Compare (); # no imports!!! guard against insane architecture
12 # not importing first() as it will clash with our own method
16 # De-duplication in _merge_attr() is disabled, but left in for reference
17 # (the merger is used for other things that ought not to be de-duped)
18 *__HM_DEDUP = sub () { 0 };
28 # this is real - CDBICompat overrides it with insanity
29 # yes, prototype won't matter, but that's for now ;)
32 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
36 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
40 my $users_rs = $schema->resultset('User');
41 while( $user = $users_rs->next) {
42 print $user->username;
45 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
46 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
50 A ResultSet is an object which stores a set of conditions representing
51 a query. It is the backbone of DBIx::Class (i.e. the really
52 important/useful bit).
54 No SQL is executed on the database when a ResultSet is created, it
55 just stores all the conditions needed to create the query.
57 A basic ResultSet representing the data of an entire table is returned
58 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
59 L<Source|DBIx::Class::Manual::Glossary/Source> name.
61 my $users_rs = $schema->resultset('User');
63 A new ResultSet is returned from calling L</search> on an existing
64 ResultSet. The new one will contain all the conditions of the
65 original, plus any new conditions added in the C<search> call.
67 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
68 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
71 The query that the ResultSet represents is B<only> executed against
72 the database when these methods are called:
73 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
75 If a resultset is used in a numeric context it returns the L</count>.
76 However, if it is used in a boolean context it is B<always> true. So if
77 you want to check if a resultset has any results, you must use C<if $rs
80 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
82 If you want to make your custom ResultSet classes with L<Moose>, use a template
85 package MyApp::Schema::ResultSet::User;
88 use namespace::autoclean;
90 extends 'DBIx::Class::ResultSet';
92 sub BUILDARGS { $_[2] }
96 __PACKAGE__->meta->make_immutable;
100 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
101 clash with the regular ResultSet constructor. Alternatively, you can use:
103 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
105 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
106 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
110 =head2 Chaining resultsets
112 Let's say you've got a query that needs to be run to return some data
113 to the user. But, you have an authorization system in place that
114 prevents certain users from seeing certain information. So, you want
115 to construct the basic query in one method, but add constraints to it in
120 my $request = $self->get_request; # Get a request object somehow.
121 my $schema = $self->result_source->schema;
123 my $cd_rs = $schema->resultset('CD')->search({
124 title => $request->param('title'),
125 year => $request->param('year'),
128 $cd_rs = $self->apply_security_policy( $cd_rs );
130 return $cd_rs->all();
133 sub apply_security_policy {
142 =head3 Resolving conditions and attributes
144 When a resultset is chained from another resultset (ie:
145 C<my $new_rs = $old_rs->search(\%extra_cond, \%attrs)>), conditions
146 and attributes with the same keys need resolving.
148 If any of L</columns>, L</select>, L</as> are present, they reset the
149 original selection, and start the selection "clean".
151 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
152 are merged into the existing ones from the original resultset.
154 The L</where> and L</having> attributes, and any search conditions, are
155 merged with an SQL C<AND> to the existing condition from the original
158 All other attributes are overridden by any new ones supplied in the
161 =head2 Multiple queries
163 Since a resultset just defines a query, you can do all sorts of
164 things with it with the same object.
166 # Don't hit the DB yet.
167 my $cd_rs = $schema->resultset('CD')->search({
168 title => 'something',
172 # Each of these hits the DB individually.
173 my $count = $cd_rs->count;
174 my $most_recent = $cd_rs->get_column('date_released')->max();
175 my @records = $cd_rs->all;
177 And it's not just limited to SELECT statements.
183 $cd_rs->create({ artist => 'Fred' });
185 Which is the same as:
187 $schema->resultset('CD')->create({
188 title => 'something',
193 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
201 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
203 =item Return Value: L<$resultset|/search>
207 The resultset constructor. Takes a source object (usually a
208 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
209 L</ATTRIBUTES> below). Does not perform any queries -- these are
210 executed as needed by the other methods.
212 Generally you never construct a resultset manually. Instead you get one
214 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
215 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
218 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
224 If called on an object, proxies to L</new_result> instead, so
226 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
228 will return a CD object, not a ResultSet, and is equivalent to:
230 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
232 Please also keep in mind that many internals call L</new_result> directly,
233 so overloading this method with the idea of intercepting new result object
234 creation B<will not work>. See also warning pertaining to L</create>.
242 return $class->new_result(@_) if ref $class;
244 my ($source, $attrs) = @_;
245 $source = $source->resolve
246 if $source->isa('DBIx::Class::ResultSourceHandle');
248 $attrs = { %{$attrs||{}} };
249 delete @{$attrs}{qw(_sqlmaker_select_args _related_results_construction)};
251 if ($attrs->{page}) {
252 $attrs->{rows} ||= 10;
255 $attrs->{alias} ||= 'me';
258 result_source => $source,
259 cond => $attrs->{where},
264 # if there is a dark selector, this means we are already in a
265 # chain and the cleanup/sanification was taken care of by
267 $self->_normalize_selection($attrs)
268 unless $attrs->{_dark_selector};
271 $attrs->{result_class} || $source->result_class
281 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
283 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
287 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
288 my $new_rs = $cd_rs->search({ year => 2005 });
290 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
291 # year = 2005 OR year = 2004
293 In list context, C<< ->all() >> is called implicitly on the resultset, thus
294 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
295 To avoid that, use L</search_rs>.
297 If you need to pass in additional attributes but no additional condition,
298 call it as C<search(undef, \%attrs)>.
300 # "SELECT name, artistid FROM $artist_table"
301 my @all_artists = $schema->resultset('Artist')->search(undef, {
302 columns => [qw/name artistid/],
305 For a list of attributes that can be passed to C<search>, see
306 L</ATTRIBUTES>. For more examples of using this function, see
307 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
308 documentation for the first argument, see L<SQL::Abstract>
309 and its extension L<DBIx::Class::SQLMaker>.
311 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
315 Note that L</search> does not process/deflate any of the values passed in the
316 L<SQL::Abstract>-compatible search condition structure. This is unlike other
317 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
318 manually that any value passed to this method will stringify to something the
319 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
320 objects, for more info see:
321 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
327 my $rs = $self->search_rs( @_ );
332 elsif (defined wantarray) {
336 # we can be called by a relationship helper, which in
337 # turn may be called in void context due to some braindead
338 # overload or whatever else the user decided to be clever
339 # at this particular day. Thus limit the exception to
340 # external code calls only
341 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
342 if (caller)[0] !~ /^\QDBIx::Class::/;
352 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
354 =item Return Value: L<$resultset|/search>
358 This method does the same exact thing as search() except it will
359 always return a resultset, even in list context.
366 my $rsrc = $self->result_source;
367 my ($call_cond, $call_attrs);
369 # Special-case handling for (undef, undef) or (undef)
370 # Note that (foo => undef) is valid deprecated syntax
371 @_ = () if not scalar grep { defined $_ } @_;
377 # fish out attrs in the ($condref, $attr) case
378 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
379 ($call_cond, $call_attrs) = @_;
382 $self->throw_exception('Odd number of arguments to search')
386 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
387 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
389 for my $i (0 .. $#_) {
391 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
392 if (! defined $_[$i] or ref $_[$i] ne '');
398 # see if we can keep the cache (no $rs changes)
400 my %safe = (alias => 1, cache => 1);
401 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
404 ref $call_cond eq 'HASH' && ! keys %$call_cond
406 ref $call_cond eq 'ARRAY' && ! @$call_cond
408 $cache = $self->get_cache;
411 my $old_attrs = { %{$self->{attrs}} };
412 my ($old_having, $old_where) = delete @{$old_attrs}{qw(having where)};
414 my $new_attrs = { %$old_attrs };
416 # take care of call attrs (only if anything is changing)
417 if ($call_attrs and keys %$call_attrs) {
419 # copy for _normalize_selection
420 $call_attrs = { %$call_attrs };
422 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
424 # reset the current selector list if new selectors are supplied
425 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
426 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
429 # Normalize the new selector list (operates on the passed-in attr structure)
430 # Need to do it on every chain instead of only once on _resolved_attrs, in
431 # order to allow detection of empty vs partial 'as'
432 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
433 if $old_attrs->{_dark_selector};
434 $self->_normalize_selection ($call_attrs);
436 # start with blind overwriting merge, exclude selector attrs
437 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
438 delete @{$new_attrs}{@selector_attrs};
440 for (@selector_attrs) {
441 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
442 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
445 # older deprecated name, use only if {columns} is not there
446 if (my $c = delete $new_attrs->{cols}) {
447 carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
448 if ($new_attrs->{columns}) {
449 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
452 $new_attrs->{columns} = $c;
457 # join/prefetch use their own crazy merging heuristics
458 foreach my $key (qw/join prefetch/) {
459 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
460 if exists $call_attrs->{$key};
463 # stack binds together
464 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
468 for ($old_where, $call_cond) {
470 $new_attrs->{where} = $self->_stack_cond (
471 $_, $new_attrs->{where}
476 if (defined $old_having) {
477 $new_attrs->{having} = $self->_stack_cond (
478 $old_having, $new_attrs->{having}
482 my $rs = (ref $self)->new($rsrc, $new_attrs);
484 $rs->set_cache($cache) if ($cache);
490 sub _normalize_selection {
491 my ($self, $attrs) = @_;
494 if ( exists $attrs->{include_columns} ) {
495 carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
496 $attrs->{'+columns'} = $self->_merge_attr(
497 $attrs->{'+columns'}, delete $attrs->{include_columns}
501 # columns are always placed first, however
503 # Keep the X vs +X separation until _resolved_attrs time - this allows to
504 # delay the decision on whether to use a default select list ($rsrc->columns)
505 # allowing stuff like the remove_columns helper to work
507 # select/as +select/+as pairs need special handling - the amount of select/as
508 # elements in each pair does *not* have to be equal (think multicolumn
509 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
510 # supplied at all) - try to infer the alias, either from the -as parameter
511 # of the selector spec, or use the parameter whole if it looks like a column
512 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
513 # is ok as well), but make sure no more additions to the 'as' chain take place
514 for my $pref ('', '+') {
516 my ($sel, $as) = map {
517 my $key = "${pref}${_}";
519 my $val = [ ref $attrs->{$key} eq 'ARRAY'
521 : $attrs->{$key} || ()
523 delete $attrs->{$key};
527 if (! @$as and ! @$sel ) {
530 elsif (@$as and ! @$sel) {
531 $self->throw_exception(
532 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
536 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
537 # if any @$as has been supplied we assume the user knows what (s)he is doing
538 # and blindly keep stacking up pieces
539 unless ($attrs->{_dark_selector}) {
542 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
543 push @$as, $_->{-as};
545 # assume any plain no-space, no-parenthesis string to be a column spec
546 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
547 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
550 # if all else fails - raise a flag that no more aliasing will be allowed
552 $attrs->{_dark_selector} = {
554 string => ($dark_sel_dumper ||= do {
555 require Data::Dumper::Concise;
556 Data::Dumper::Concise::DumperObject()->Indent(0);
557 })->Values([$_])->Dump
565 elsif (@$as < @$sel) {
566 $self->throw_exception(
567 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
570 elsif ($pref and $attrs->{_dark_selector}) {
571 $self->throw_exception(
572 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
578 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
579 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
584 my ($self, $left, $right) = @_;
586 # collapse single element top-level conditions
587 # (single pass only, unlikely to need recursion)
588 for ($left, $right) {
589 if (ref $_ eq 'ARRAY') {
597 elsif (ref $_ eq 'HASH') {
598 my ($first, $more) = keys %$_;
601 if (! defined $first) {
605 elsif (! defined $more) {
606 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
609 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
616 # merge hashes with weeding out of duplicates (simple cases only)
617 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
619 # shallow copy to destroy
620 $right = { %$right };
621 for (grep { exists $right->{$_} } keys %$left) {
622 # the use of eq_deeply here is justified - the rhs of an
623 # expression can contain a lot of twisted weird stuff
624 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
627 $right = undef unless keys %$right;
631 if (defined $left xor defined $right) {
632 return defined $left ? $left : $right;
634 elsif (! defined $left) {
638 return { -and => [ $left, $right ] };
642 =head2 search_literal
644 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
645 should only be used in that context. C<search_literal> is a convenience
646 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
647 want to ensure columns are bound correctly, use L</search>.
649 See L<DBIx::Class::Manual::Cookbook/Searching> and
650 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
651 require C<search_literal>.
655 =item Arguments: $sql_fragment, @standalone_bind_values
657 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
661 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
662 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
664 Pass a literal chunk of SQL to be added to the conditional part of the
667 Example of how to use C<search> instead of C<search_literal>
669 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
670 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
675 my ($self, $sql, @bind) = @_;
677 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
680 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
687 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
689 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
693 Finds and returns a single row based on supplied criteria. Takes either a
694 hashref with the same format as L</create> (including inference of foreign
695 keys from related objects), or a list of primary key values in the same
696 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
697 declaration on the L</result_source>.
699 In either case an attempt is made to combine conditions already existing on
700 the resultset with the condition passed to this method.
702 To aid with preparing the correct query for the storage you may supply the
703 C<key> attribute, which is the name of a
704 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
705 unique constraint corresponding to the
706 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
707 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
708 to construct a query that satisfies the named unique constraint fully (
709 non-NULL values for each column member of the constraint) an exception is
712 If no C<key> is specified, the search is carried over all unique constraints
713 which are fully defined by the available condition.
715 If no such constraint is found, C<find> currently defaults to a simple
716 C<< search->(\%column_values) >> which may or may not do what you expect.
717 Note that this fallback behavior may be deprecated in further versions. If
718 you need to search with arbitrary conditions - use L</search>. If the query
719 resulting from this fallback produces more than one row, a warning to the
720 effect is issued, though only the first row is constructed and returned as
723 In addition to C<key>, L</find> recognizes and applies standard
724 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
726 Note that if you have extra concerns about the correctness of the resulting
727 query you need to specify the C<key> attribute and supply the entire condition
728 as an argument to find (since it is not always possible to perform the
729 combination of the resultset condition with the supplied one, especially if
730 the resultset condition contains literal sql).
732 For example, to find a row by its primary key:
734 my $cd = $schema->resultset('CD')->find(5);
736 You can also find a row by a specific unique constraint:
738 my $cd = $schema->resultset('CD')->find(
740 artist => 'Massive Attack',
741 title => 'Mezzanine',
743 { key => 'cd_artist_title' }
746 See also L</find_or_create> and L</update_or_create>.
752 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
754 my $rsrc = $self->result_source;
757 if (exists $attrs->{key}) {
758 $constraint_name = defined $attrs->{key}
760 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
764 # Parse out the condition from input
767 if (ref $_[0] eq 'HASH') {
768 $call_cond = { %{$_[0]} };
771 # if only values are supplied we need to default to 'primary'
772 $constraint_name = 'primary' unless defined $constraint_name;
774 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
776 $self->throw_exception(
777 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
780 $self->throw_exception (
781 'find() expects either a column/value hashref, or a list of values '
782 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
783 ) unless @c_cols == @_;
786 @{$call_cond}{@c_cols} = @_;
790 for my $key (keys %$call_cond) {
792 my $keyref = ref($call_cond->{$key})
794 my $relinfo = $rsrc->relationship_info($key)
796 my $val = delete $call_cond->{$key};
798 next if $keyref eq 'ARRAY'; # has_many for multi_create
800 my $rel_q = $rsrc->_resolve_condition(
801 $relinfo->{cond}, $val, $key, $key
803 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
804 @related{keys %$rel_q} = values %$rel_q;
808 # relationship conditions take precedence (?)
809 @{$call_cond}{keys %related} = values %related;
811 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
813 if (defined $constraint_name) {
814 $final_cond = $self->_qualify_cond_columns (
816 $self->_build_unique_cond (
824 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
825 # This means that we got here after a merger of relationship conditions
826 # in ::Relationship::Base::search_related (the row method), and furthermore
827 # the relationship is of the 'single' type. This means that the condition
828 # provided by the relationship (already attached to $self) is sufficient,
829 # as there can be only one row in the database that would satisfy the
833 # no key was specified - fall down to heuristics mode:
834 # run through all unique queries registered on the resultset, and
835 # 'OR' all qualifying queries together
836 my (@unique_queries, %seen_column_combinations);
837 for my $c_name ($rsrc->unique_constraint_names) {
838 next if $seen_column_combinations{
839 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
842 push @unique_queries, try {
843 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
847 $final_cond = @unique_queries
848 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
849 : $self->_non_unique_find_fallback ($call_cond, $attrs)
853 # Run the query, passing the result_class since it should propagate for find
854 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
855 if ($rs->_resolved_attrs->{collapse}) {
857 carp "Query returned more than one row" if $rs->next;
865 # This is a stop-gap method as agreed during the discussion on find() cleanup:
866 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
868 # It is invoked when find() is called in legacy-mode with insufficiently-unique
869 # condition. It is provided for overrides until a saner way forward is devised
871 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
872 # the road. Please adjust your tests accordingly to catch this situation early
873 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
875 # The method will not be removed without an adequately complete replacement
876 # for strict-mode enforcement
877 sub _non_unique_find_fallback {
878 my ($self, $cond, $attrs) = @_;
880 return $self->_qualify_cond_columns(
882 exists $attrs->{alias}
884 : $self->{attrs}{alias}
889 sub _qualify_cond_columns {
890 my ($self, $cond, $alias) = @_;
892 my %aliased = %$cond;
893 for (keys %aliased) {
894 $aliased{"$alias.$_"} = delete $aliased{$_}
901 sub _build_unique_cond {
902 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
904 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
906 # combination may fail if $self->{cond} is non-trivial
907 my ($final_cond) = try {
908 $self->_merge_with_rscond ($extra_cond)
913 # trim out everything not in $columns
914 $final_cond = { map {
915 exists $final_cond->{$_}
916 ? ( $_ => $final_cond->{$_} )
920 if (my @missing = grep
921 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
924 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
926 join (', ', map { "'$_'" } @missing),
933 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
935 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
937 carp_unique ( sprintf (
938 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
939 . 'values in column(s): %s). This is almost certainly not what you wanted, '
940 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
942 join (', ', map { "'$_'" } @undefs),
949 =head2 search_related
953 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
955 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
959 $new_rs = $cd_rs->search_related('artist', {
963 Searches the specified relationship, optionally specifying a condition and
964 attributes for matching records. See L</ATTRIBUTES> for more information.
966 In list context, C<< ->all() >> is called implicitly on the resultset, thus
967 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
969 See also L</search_related_rs>.
974 return shift->related_resultset(shift)->search(@_);
977 =head2 search_related_rs
979 This method works exactly the same as search_related, except that
980 it guarantees a resultset, even in list context.
984 sub search_related_rs {
985 return shift->related_resultset(shift)->search_rs(@_);
992 =item Arguments: none
994 =item Return Value: L<$cursor|DBIx::Class::Cursor>
998 Returns a storage-driven cursor to the given resultset. See
999 L<DBIx::Class::Cursor> for more information.
1006 return $self->{cursor} ||= do {
1007 my $attrs = $self->_resolved_attrs;
1008 $self->result_source->storage->select(
1009 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1018 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1020 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1024 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1026 Inflates the first result without creating a cursor if the resultset has
1027 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1030 While this method can take an optional search condition (just like L</search>)
1031 being a fast-code-path it does not recognize search attributes. If you need to
1032 add extra joins or similar, call L</search> and then chain-call L</single> on the
1033 L<DBIx::Class::ResultSet> returned.
1039 As of 0.08100, this method enforces the assumption that the preceding
1040 query returns only one row. If more than one row is returned, you will receive
1043 Query returned more than one row
1045 In this case, you should be using L</next> or L</find> instead, or if you really
1046 know what you are doing, use the L</rows> attribute to explicitly limit the size
1049 This method will also throw an exception if it is called on a resultset prefetching
1050 has_many, as such a prefetch implies fetching multiple rows from the database in
1051 order to assemble the resulting object.
1058 my ($self, $where) = @_;
1060 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1063 my $attrs = { %{$self->_resolved_attrs} };
1065 $self->throw_exception(
1066 'single() can not be used on resultsets collapsing a has_many. Use find( \%cond ) or next() instead'
1067 ) if $attrs->{collapse};
1070 if (defined $attrs->{where}) {
1073 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1074 $where, delete $attrs->{where} ]
1077 $attrs->{where} = $where;
1081 my $data = [ $self->result_source->storage->select_single(
1082 $attrs->{from}, $attrs->{select},
1083 $attrs->{where}, $attrs
1086 return undef unless @$data;
1087 $self->{_stashed_rows} = [ $data ];
1088 $self->_construct_results->[0];
1094 # Recursively collapse the query, accumulating values for each column.
1096 sub _collapse_query {
1097 my ($self, $query, $collapsed) = @_;
1101 if (ref $query eq 'ARRAY') {
1102 foreach my $subquery (@$query) {
1103 next unless ref $subquery; # -or
1104 $collapsed = $self->_collapse_query($subquery, $collapsed);
1107 elsif (ref $query eq 'HASH') {
1108 if (keys %$query and (keys %$query)[0] eq '-and') {
1109 foreach my $subquery (@{$query->{-and}}) {
1110 $collapsed = $self->_collapse_query($subquery, $collapsed);
1114 foreach my $col (keys %$query) {
1115 my $value = $query->{$col};
1116 $collapsed->{$col}{$value}++;
1128 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1130 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1134 my $max_length = $rs->get_column('length')->max;
1136 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1141 my ($self, $column) = @_;
1142 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1150 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1152 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1156 # WHERE title LIKE '%blue%'
1157 $cd_rs = $rs->search_like({ title => '%blue%'});
1159 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1160 that this is simply a convenience method retained for ex Class::DBI users.
1161 You most likely want to use L</search> with specific operators.
1163 For more information, see L<DBIx::Class::Manual::Cookbook>.
1165 This method is deprecated and will be removed in 0.09. Use L</search()>
1166 instead. An example conversion is:
1168 ->search_like({ foo => 'bar' });
1172 ->search({ foo => { like => 'bar' } });
1179 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1180 .' Instead use ->search({ x => { -like => "y%" } })'
1181 .' (note the outer pair of {}s - they are important!)'
1183 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1184 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1185 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1186 return $class->search($query, { %$attrs });
1193 =item Arguments: $first, $last
1195 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1199 Returns a resultset or object list representing a subset of elements from the
1200 resultset slice is called on. Indexes are from 0, i.e., to get the first
1201 three records, call:
1203 my ($one, $two, $three) = $rs->slice(0, 2);
1208 my ($self, $min, $max) = @_;
1209 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1210 $attrs->{offset} = $self->{attrs}{offset} || 0;
1211 $attrs->{offset} += $min;
1212 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1213 return $self->search(undef, $attrs);
1214 #my $slice = (ref $self)->new($self->result_source, $attrs);
1215 #return (wantarray ? $slice->all : $slice);
1222 =item Arguments: none
1224 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1228 Returns the next element in the resultset (C<undef> is there is none).
1230 Can be used to efficiently iterate over records in the resultset:
1232 my $rs = $schema->resultset('CD')->search;
1233 while (my $cd = $rs->next) {
1237 Note that you need to store the resultset object, and call C<next> on it.
1238 Calling C<< resultset('Table')->next >> repeatedly will always return the
1239 first record from the resultset.
1246 if (my $cache = $self->get_cache) {
1247 $self->{all_cache_position} ||= 0;
1248 return $cache->[$self->{all_cache_position}++];
1251 if ($self->{attrs}{cache}) {
1252 delete $self->{pager};
1253 $self->{all_cache_position} = 1;
1254 return ($self->all)[0];
1257 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1259 $self->{_stashed_results} = $self->_construct_results
1262 return shift @{$self->{_stashed_results}};
1265 # Constructs as many results as it can in one pass while respecting
1266 # cursor laziness. Several modes of operation:
1268 # * Always builds everything present in @{$self->{_stashed_rows}}
1269 # * If called with $fetch_all true - pulls everything off the cursor and
1270 # builds all result structures (or objects) in one pass
1271 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1272 # and if the resultset is ordered properly by the left side:
1273 # * Fetches stuff off the cursor until the "master object" changes,
1274 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1276 # * Just fetches, and collapses/constructs everything as if $fetch_all
1277 # was requested (there is no other way to collapse except for an
1279 # * If no collapse is requested - just get the next row, construct and
1281 sub _construct_results {
1282 my ($self, $fetch_all) = @_;
1284 my $rsrc = $self->result_source;
1285 my $attrs = $self->_resolved_attrs;
1290 ! $attrs->{order_by}
1294 my @pcols = $rsrc->primary_columns
1296 # default order for collapsing unless the user asked for something
1297 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
1298 $attrs->{_ordered_for_collapse} = 1;
1299 $attrs->{_order_is_artificial} = 1;
1302 my $cursor = $self->cursor;
1304 # this will be used as both initial raw-row collector AND as a RV of
1305 # _construct_results. Not regrowing the array twice matters a lot...
1306 # a surprising amount actually
1307 my $rows = delete $self->{_stashed_rows};
1309 my $did_fetch_all = $fetch_all;
1312 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1313 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1315 elsif( $attrs->{collapse} ) {
1317 $attrs->{_ordered_for_collapse} = (
1323 ->_main_source_order_by_portion_is_stable($rsrc, $attrs->{order_by}, $attrs->{where})
1325 ) unless defined $attrs->{_ordered_for_collapse};
1327 if (! $attrs->{_ordered_for_collapse}) {
1330 # instead of looping over ->next, use ->all in stealth mode
1331 # *without* calling a ->reset afterwards
1332 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1333 if (! $cursor->{_done}) {
1334 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1335 $cursor->{_done} = 1;
1340 if (! $did_fetch_all and ! @{$rows||[]} ) {
1341 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1342 if (scalar (my @r = $cursor->next) ) {
1347 return undef unless @{$rows||[]};
1349 # sanity check - people are too clever for their own good
1350 if ($attrs->{collapse} and my $aliastypes = $attrs->{_sqlmaker_select_args}[3]{_aliastypes} ) {
1352 my $multiplied_selectors;
1353 for my $sel_alias ( grep { $_ ne $attrs->{alias} } keys %{ $aliastypes->{selecting} } ) {
1355 $aliastypes->{multiplying}{$sel_alias}
1357 scalar grep { $aliastypes->{multiplying}{(values %$_)[0]} } @{ $aliastypes->{selecting}{$sel_alias}{-parents} }
1359 $multiplied_selectors->{$_} = 1 for values %{$aliastypes->{selecting}{$sel_alias}{-seen_columns}}
1363 for my $i (0 .. $#{$attrs->{as}} ) {
1364 my $sel = $attrs->{select}[$i];
1366 if (ref $sel eq 'SCALAR') {
1369 elsif( ref $sel eq 'REF' and ref $$sel eq 'ARRAY' ) {
1373 $self->throw_exception(
1374 'Result collapse not possible - selection from a has_many source redirected to the main object'
1375 ) if ($multiplied_selectors->{$sel} and $attrs->{as}[$i] !~ /\./);
1379 # hotspot - skip the setter
1380 my $res_class = $self->_result_class;
1382 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1383 $res_class->can ('inflate_result')
1384 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1387 my $infmap = $attrs->{as};
1389 $self->{_result_inflator}{is_core_row} = ( (
1392 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1393 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1395 $self->{_result_inflator}{is_hri} = ( (
1396 ! $self->{_result_inflator}{is_core_row}
1399 require DBIx::Class::ResultClass::HashRefInflator
1401 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1403 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1406 if (! $attrs->{_related_results_construction}) {
1407 # construct a much simpler array->hash folder for the one-table cases right here
1408 if ($self->{_result_inflator}{is_hri}) {
1409 for my $r (@$rows) {
1410 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1413 # FIXME SUBOPTIMAL this is a very very very hot spot
1414 # while rather optimal we can *still* do much better, by
1415 # building a smarter Row::inflate_result(), and
1416 # switch to feeding it data via a much leaner interface
1418 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1419 # this particular resultset size
1420 elsif (@$rows < 60) {
1421 for my $r (@$rows) {
1422 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1427 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1428 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1434 $self->{_result_inflator}{is_hri} ? 'hri'
1435 : $self->{_result_inflator}{is_core_row} ? 'classic_pruning'
1436 : 'classic_nonpruning'
1439 # $args and $attrs to _mk_row_parser are seperated to delineate what is
1440 # core collapser stuff and what is dbic $rs specific
1441 @{$self->{_row_parser}{$parser_type}}{qw(cref nullcheck)} = $rsrc->_mk_row_parser({
1443 inflate_map => $infmap,
1444 collapse => $attrs->{collapse},
1445 premultiplied => $attrs->{_main_source_premultiplied},
1446 hri_style => $self->{_result_inflator}{is_hri},
1447 prune_null_branches => $self->{_result_inflator}{is_hri} || $self->{_result_inflator}{is_core_row},
1448 }, $attrs) unless $self->{_row_parser}{$parser_type}{cref};
1450 # column_info metadata historically hasn't been too reliable.
1451 # We need to start fixing this somehow (the collapse resolver
1452 # can't work without it). Add an explicit check for the *main*
1453 # result, hopefully this will gradually weed out such errors
1455 # FIXME - this is a temporary kludge that reduces perfromance
1456 # It is however necessary for the time being
1457 my ($unrolled_non_null_cols_to_check, $err);
1459 if (my $check_non_null_cols = $self->{_row_parser}{$parser_type}{nullcheck} ) {
1462 'Collapse aborted due to invalid ResultSource metadata - the following '
1463 . 'selections are declared non-nullable but NULLs were retrieved: '
1467 COL: for my $i (@$check_non_null_cols) {
1468 ! defined $_->[$i] and push @violating_idx, $i and next COL for @$rows;
1471 $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
1474 $unrolled_non_null_cols_to_check = join (',', @$check_non_null_cols);
1478 ($did_fetch_all or ! $attrs->{collapse}) ? undef
1479 : defined $unrolled_non_null_cols_to_check ? eval sprintf <<'EOS', $unrolled_non_null_cols_to_check
1481 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1482 my @r = $cursor->next or return;
1483 if (my @violating_idx = grep { ! defined $r[$_] } (%s) ) {
1484 $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
1490 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1491 my @r = $cursor->next or return;
1496 $self->{_row_parser}{$parser_type}{cref}->(
1498 $next_cref ? ( $next_cref, $self->{_stashed_rows} = [] ) : (),
1501 # Special-case multi-object HRI - there is no $inflator_cref pass
1502 unless ($self->{_result_inflator}{is_hri}) {
1503 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows
1507 # The @$rows check seems odd at first - why wouldn't we want to warn
1508 # regardless? The issue is things like find() etc, where the user
1509 # *knows* only one result will come back. In these cases the ->all
1510 # is not a pessimization, but rather something we actually want
1512 'Unable to properly collapse has_many results in iterator mode due '
1513 . 'to order criteria - performed an eager cursor slurp underneath. '
1514 . 'Consider using ->all() instead'
1515 ) if ( ! $fetch_all and @$rows > 1 );
1520 =head2 result_source
1524 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1526 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1530 An accessor for the primary ResultSource object from which this ResultSet
1537 =item Arguments: $result_class?
1539 =item Return Value: $result_class
1543 An accessor for the class to use when creating result objects. Defaults to
1544 C<< result_source->result_class >> - which in most cases is the name of the
1545 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1547 Note that changing the result_class will also remove any components
1548 that were originally loaded in the source class via
1549 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1550 in the original source class will not run.
1555 my ($self, $result_class) = @_;
1556 if ($result_class) {
1558 # don't fire this for an object
1559 $self->ensure_class_loaded($result_class)
1560 unless ref($result_class);
1562 if ($self->get_cache) {
1563 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1565 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1566 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1567 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1570 $self->_result_class($result_class);
1572 delete $self->{_result_inflator};
1574 $self->_result_class;
1581 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1583 =item Return Value: $count
1587 Performs an SQL C<COUNT> with the same query as the resultset was built
1588 with to find the number of elements. Passing arguments is equivalent to
1589 C<< $rs->search ($cond, \%attrs)->count >>
1595 return $self->search(@_)->count if @_ and defined $_[0];
1596 return scalar @{ $self->get_cache } if $self->get_cache;
1598 my $attrs = { %{ $self->_resolved_attrs } };
1600 # this is a little optimization - it is faster to do the limit
1601 # adjustments in software, instead of a subquery
1602 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1605 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1606 $crs = $self->_count_subq_rs ($attrs);
1609 $crs = $self->_count_rs ($attrs);
1611 my $count = $crs->next;
1613 $count -= $offset if $offset;
1614 $count = $rows if $rows and $rows < $count;
1615 $count = 0 if ($count < 0);
1624 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1626 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1630 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1631 This can be very handy for subqueries:
1633 ->search( { amount => $some_rs->count_rs->as_query } )
1635 As with regular resultsets the SQL query will be executed only after
1636 the resultset is accessed via L</next> or L</all>. That would return
1637 the same single value obtainable via L</count>.
1643 return $self->search(@_)->count_rs if @_;
1645 # this may look like a lack of abstraction (count() does about the same)
1646 # but in fact an _rs *must* use a subquery for the limits, as the
1647 # software based limiting can not be ported if this $rs is to be used
1648 # in a subquery itself (i.e. ->as_query)
1649 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1650 return $self->_count_subq_rs($self->{_attrs});
1653 return $self->_count_rs($self->{_attrs});
1658 # returns a ResultSetColumn object tied to the count query
1661 my ($self, $attrs) = @_;
1663 my $rsrc = $self->result_source;
1665 my $tmp_attrs = { %$attrs };
1666 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1667 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1669 # overwrite the selector (supplied by the storage)
1670 $rsrc->resultset_class->new($rsrc, {
1672 select => $rsrc->storage->_count_select ($rsrc, $attrs),
1674 })->get_column ('count');
1678 # same as above but uses a subquery
1680 sub _count_subq_rs {
1681 my ($self, $attrs) = @_;
1683 my $rsrc = $self->result_source;
1685 my $sub_attrs = { %$attrs };
1686 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1687 delete @{$sub_attrs}{qw/collapse columns as select order_by for/};
1689 # if we multi-prefetch we group_by something unique, as this is what we would
1690 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1691 if ( $attrs->{collapse} ) {
1692 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1693 $rsrc->_identifying_column_set || $self->throw_exception(
1694 'Unable to construct a unique group_by criteria properly collapsing the '
1695 . 'has_many prefetch before count()'
1700 # Calculate subquery selector
1701 if (my $g = $sub_attrs->{group_by}) {
1703 my $sql_maker = $rsrc->storage->sql_maker;
1705 # necessary as the group_by may refer to aliased functions
1707 for my $sel (@{$attrs->{select}}) {
1708 $sel_index->{$sel->{-as}} = $sel
1709 if (ref $sel eq 'HASH' and $sel->{-as});
1712 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1713 # also look for named aggregates referred in the having clause
1714 # having often contains scalarrefs - thus parse it out entirely
1716 if ($attrs->{having}) {
1717 local $sql_maker->{having_bind};
1718 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1719 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1720 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1721 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1722 # if we don't unset it we screw up retarded but unfortunately working
1723 # 'MAX(foo.bar)' => { '>', 3 }
1724 $sql_maker->{name_sep} = '';
1727 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1729 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1732 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1733 # and if all fails for an utterly naive quoted scalar-with-function
1734 while ($having_sql =~ /
1735 $rquote $sep $lquote (.+?) $rquote
1737 [\s,] \w+ \. (\w+) [\s,]
1739 [\s,] $lquote (.+?) $rquote [\s,]
1741 my $part = $1 || $2 || $3; # one of them matched if we got here
1742 unless ($seen_having{$part}++) {
1749 my $colpiece = $sel_index->{$_} || $_;
1751 # unqualify join-based group_by's. Arcane but possible query
1752 # also horrible horrible hack to alias a column (not a func.)
1753 # (probably need to introduce SQLA syntax)
1754 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1757 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1759 push @{$sub_attrs->{select}}, $colpiece;
1763 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1764 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1767 return $rsrc->resultset_class
1768 ->new ($rsrc, $sub_attrs)
1770 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1771 ->get_column ('count');
1775 =head2 count_literal
1777 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1778 should only be used in that context. See L</search_literal> for further info.
1782 =item Arguments: $sql_fragment, @standalone_bind_values
1784 =item Return Value: $count
1788 Counts the results in a literal query. Equivalent to calling L</search_literal>
1789 with the passed arguments, then L</count>.
1793 sub count_literal { shift->search_literal(@_)->count; }
1799 =item Arguments: none
1801 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1805 Returns all elements in the resultset.
1812 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1815 delete @{$self}{qw/_stashed_rows _stashed_results/};
1817 if (my $c = $self->get_cache) {
1821 $self->cursor->reset;
1823 my $objs = $self->_construct_results('fetch_all') || [];
1825 $self->set_cache($objs) if $self->{attrs}{cache};
1834 =item Arguments: none
1836 =item Return Value: $self
1840 Resets the resultset's cursor, so you can iterate through the elements again.
1841 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1849 delete @{$self}{qw/_stashed_rows _stashed_results/};
1850 $self->{all_cache_position} = 0;
1851 $self->cursor->reset;
1859 =item Arguments: none
1861 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1865 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1866 an object for the first result (or C<undef> if the resultset is empty).
1871 return $_[0]->reset->next;
1877 # Determines whether and what type of subquery is required for the $rs operation.
1878 # If grouping is necessary either supplies its own, or verifies the current one
1879 # After all is done delegates to the proper storage method.
1881 sub _rs_update_delete {
1882 my ($self, $op, $values) = @_;
1884 my $rsrc = $self->result_source;
1885 my $storage = $rsrc->schema->storage;
1887 my $attrs = { %{$self->_resolved_attrs} };
1889 my $join_classifications;
1890 my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
1892 # do we need a subquery for any reason?
1894 defined $existing_group_by
1896 # if {from} is unparseable wrap a subq
1897 ref($attrs->{from}) ne 'ARRAY'
1899 # limits call for a subq
1900 $self->_has_resolved_attr(qw/rows offset/)
1903 # simplify the joinmap, so we can further decide if a subq is necessary
1904 if (!$needs_subq and @{$attrs->{from}} > 1) {
1906 ($attrs->{from}, $join_classifications) =
1907 $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1909 # any non-pruneable non-local restricting joins imply subq
1910 $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
1913 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1915 (ref $attrs->{from}[0]) ne 'HASH'
1917 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1921 # do we need anything like a subquery?
1922 if (! $needs_subq) {
1923 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1924 # a condition containing 'me' or other table prefixes will not work
1925 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1927 my $sqla = $rsrc->storage->sql_maker;
1928 local $sqla->{_dequalify_idents} = 1;
1929 \[ $sqla->_recurse_where($self->{cond}) ];
1933 # we got this far - means it is time to wrap a subquery
1934 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1936 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1942 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1943 delete $attrs->{$_} for qw/select as collapse/;
1944 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1946 # this will be consumed by the pruner waaaaay down the stack
1947 $attrs->{_force_prune_multiplying_joins} = 1;
1949 my $subrs = (ref $self)->new($rsrc, $attrs);
1951 if (@$idcols == 1) {
1952 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1954 elsif ($storage->_use_multicolumn_in) {
1955 # no syntax for calling this properly yet
1956 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1957 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1958 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1963 # if all else fails - get all primary keys and operate over a ORed set
1964 # wrap in a transaction for consistency
1965 # this is where the group_by/multiplication starts to matter
1969 keys %{ $join_classifications->{multiplying} || {} }
1971 # make sure if there is a supplied group_by it matches the columns compiled above
1972 # perfectly. Anything else can not be sanely executed on most databases so croak
1973 # right then and there
1974 if ($existing_group_by) {
1975 my @current_group_by = map
1976 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1981 join ("\x00", sort @current_group_by)
1983 join ("\x00", sort @{$attrs->{columns}} )
1985 $self->throw_exception (
1986 "You have just attempted a $op operation on a resultset which does group_by"
1987 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1988 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1989 . ' kind of queries. Please retry the operation with a modified group_by or'
1990 . ' without using one at all.'
1995 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1998 $guard = $storage->txn_scope_guard;
2001 for my $row ($subrs->cursor->all) {
2003 { $idcols->[$_] => $row->[$_] }
2010 my $res = $storage->$op (
2012 $op eq 'update' ? $values : (),
2016 $guard->commit if $guard;
2025 =item Arguments: \%values
2027 =item Return Value: $underlying_storage_rv
2031 Sets the specified columns in the resultset to the supplied values in a
2032 single query. Note that this will not run any accessor/set_column/update
2033 triggers, nor will it update any result object instances derived from this
2034 resultset (this includes the contents of the L<resultset cache|/set_cache>
2035 if any). See L</update_all> if you need to execute any on-update
2036 triggers or cascades defined either by you or a
2037 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2039 The return value is a pass through of what the underlying
2040 storage backend returned, and may vary. See L<DBI/execute> for the most
2045 Note that L</update> does not process/deflate any of the values passed in.
2046 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
2047 ensure manually that any value passed to this method will stringify to
2048 something the RDBMS knows how to deal with. A notable example is the
2049 handling of L<DateTime> objects, for more info see:
2050 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
2055 my ($self, $values) = @_;
2056 $self->throw_exception('Values for update must be a hash')
2057 unless ref $values eq 'HASH';
2059 return $self->_rs_update_delete ('update', $values);
2066 =item Arguments: \%values
2068 =item Return Value: 1
2072 Fetches all objects and updates them one at a time via
2073 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2074 triggers, while L</update> will not.
2079 my ($self, $values) = @_;
2080 $self->throw_exception('Values for update_all must be a hash')
2081 unless ref $values eq 'HASH';
2083 my $guard = $self->result_source->schema->txn_scope_guard;
2084 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2093 =item Arguments: none
2095 =item Return Value: $underlying_storage_rv
2099 Deletes the rows matching this resultset in a single query. Note that this
2100 will not run any delete triggers, nor will it alter the
2101 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2102 derived from this resultset (this includes the contents of the
2103 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2104 execute any on-delete triggers or cascades defined either by you or a
2105 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2107 The return value is a pass through of what the underlying storage backend
2108 returned, and may vary. See L<DBI/execute> for the most common case.
2114 $self->throw_exception('delete does not accept any arguments')
2117 return $self->_rs_update_delete ('delete');
2124 =item Arguments: none
2126 =item Return Value: 1
2130 Fetches all objects and deletes them one at a time via
2131 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2132 triggers, while L</delete> will not.
2138 $self->throw_exception('delete_all does not accept any arguments')
2141 my $guard = $self->result_source->schema->txn_scope_guard;
2142 $_->delete for $self->all;
2151 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2153 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2157 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2164 The context of this method call has an important effect on what is
2165 submitted to storage. In void context data is fed directly to fastpath
2166 insertion routines provided by the underlying storage (most often
2167 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2168 L<insert|DBIx::Class::Row/insert> calls on the
2169 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2170 augmentation of these methods provided by components. For example if you
2171 are using something like L<DBIx::Class::UUIDColumns> to create primary
2172 keys for you, you will find that your PKs are empty. In this case you
2173 will have to explicitly force scalar or list context in order to create
2178 In non-void (scalar or list) context, this method is simply a wrapper
2179 for L</create>. Depending on list or scalar context either a list of
2180 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2181 containing these objects is returned.
2183 When supplying data in "arrayref of arrayrefs" invocation style, the
2184 first element should be a list of column names and each subsequent
2185 element should be a data value in the earlier specified column order.
2188 $Arstist_rs->populate([
2189 [ qw( artistid name ) ],
2190 [ 100, 'A Formally Unknown Singer' ],
2191 [ 101, 'A singer that jumped the shark two albums ago' ],
2192 [ 102, 'An actually cool singer' ],
2195 For the arrayref of hashrefs style each hashref should be a structure
2196 suitable for passing to L</create>. Multi-create is also permitted with
2199 $schema->resultset("Artist")->populate([
2200 { artistid => 4, name => 'Manufactured Crap', cds => [
2201 { title => 'My First CD', year => 2006 },
2202 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2205 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2206 { title => 'My parents sold me to a record company', year => 2005 },
2207 { title => 'Why Am I So Ugly?', year => 2006 },
2208 { title => 'I Got Surgery and am now Popular', year => 2007 }
2213 If you attempt a void-context multi-create as in the example above (each
2214 Artist also has the related list of CDs), and B<do not> supply the
2215 necessary autoinc foreign key information, this method will proxy to the
2216 less efficient L</create>, and then throw the Result objects away. In this
2217 case there are obviously no benefits to using this method over L</create>.
2224 # cruft placed in standalone method
2225 my $data = $self->_normalize_populate_args(@_);
2227 return unless @$data;
2229 if(defined wantarray) {
2230 my @created = map { $self->create($_) } @$data;
2231 return wantarray ? @created : \@created;
2234 my $first = $data->[0];
2236 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2237 # it relationship data
2238 my (@rels, @columns);
2239 my $rsrc = $self->result_source;
2240 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2241 for (keys %$first) {
2242 my $ref = ref $first->{$_};
2243 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2249 my @pks = $rsrc->primary_columns;
2251 ## do the belongs_to relationships
2252 foreach my $index (0..$#$data) {
2254 # delegate to create() for any dataset without primary keys with specified relationships
2255 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2257 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2258 my @ret = $self->populate($data);
2264 foreach my $rel (@rels) {
2265 next unless ref $data->[$index]->{$rel} eq "HASH";
2266 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2267 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2268 my $related = $result->result_source->_resolve_condition(
2269 $reverse_relinfo->{cond},
2275 delete $data->[$index]->{$rel};
2276 $data->[$index] = {%{$data->[$index]}, %$related};
2278 push @columns, keys %$related if $index == 0;
2282 ## inherit the data locked in the conditions of the resultset
2283 my ($rs_data) = $self->_merge_with_rscond({});
2284 delete @{$rs_data}{@columns};
2286 ## do bulk insert on current row
2287 $rsrc->storage->insert_bulk(
2289 [@columns, keys %$rs_data],
2290 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2293 ## do the has_many relationships
2294 foreach my $item (@$data) {
2298 foreach my $rel (@rels) {
2299 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2301 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2303 my $child = $main_row->$rel;
2305 my $related = $child->result_source->_resolve_condition(
2306 $rels->{$rel}{cond},
2312 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2313 my @populate = map { {%$_, %$related} } @rows_to_add;
2315 $child->populate( \@populate );
2322 # populate() argumnets went over several incarnations
2323 # What we ultimately support is AoH
2324 sub _normalize_populate_args {
2325 my ($self, $arg) = @_;
2327 if (ref $arg eq 'ARRAY') {
2331 elsif (ref $arg->[0] eq 'HASH') {
2334 elsif (ref $arg->[0] eq 'ARRAY') {
2336 my @colnames = @{$arg->[0]};
2337 foreach my $values (@{$arg}[1 .. $#$arg]) {
2338 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2344 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2351 =item Arguments: none
2353 =item Return Value: L<$pager|Data::Page>
2357 Returns a L<Data::Page> object for the current resultset. Only makes
2358 sense for queries with a C<page> attribute.
2360 To get the full count of entries for a paged resultset, call
2361 C<total_entries> on the L<Data::Page> object.
2368 return $self->{pager} if $self->{pager};
2370 my $attrs = $self->{attrs};
2371 if (!defined $attrs->{page}) {
2372 $self->throw_exception("Can't create pager for non-paged rs");
2374 elsif ($attrs->{page} <= 0) {
2375 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2377 $attrs->{rows} ||= 10;
2379 # throw away the paging flags and re-run the count (possibly
2380 # with a subselect) to get the real total count
2381 my $count_attrs = { %$attrs };
2382 delete @{$count_attrs}{qw/rows offset page pager/};
2384 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2386 require DBIx::Class::ResultSet::Pager;
2387 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2388 sub { $total_rs->count }, #lazy-get the total
2390 $self->{attrs}{page},
2398 =item Arguments: $page_number
2400 =item Return Value: L<$resultset|/search>
2404 Returns a resultset for the $page_number page of the resultset on which page
2405 is called, where each page contains a number of rows equal to the 'rows'
2406 attribute set on the resultset (10 by default).
2411 my ($self, $page) = @_;
2412 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2419 =item Arguments: \%col_data
2421 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2425 Creates a new result object in the resultset's result class and returns
2426 it. The row is not inserted into the database at this point, call
2427 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2428 will tell you whether the result object has been inserted or not.
2430 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2435 my ($self, $values) = @_;
2437 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2440 $self->throw_exception( "new_result expects a hashref" )
2441 unless (ref $values eq 'HASH');
2443 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2445 my $new = $self->result_class->new({
2447 ( @$cols_from_relations
2448 ? (-cols_from_relations => $cols_from_relations)
2451 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2455 reftype($new) eq 'HASH'
2461 carp_unique (sprintf (
2462 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2463 $self->result_class,
2470 # _merge_with_rscond
2472 # Takes a simple hash of K/V data and returns its copy merged with the
2473 # condition already present on the resultset. Additionally returns an
2474 # arrayref of value/condition names, which were inferred from related
2475 # objects (this is needed for in-memory related objects)
2476 sub _merge_with_rscond {
2477 my ($self, $data) = @_;
2479 my (%new_data, @cols_from_relations);
2481 my $alias = $self->{attrs}{alias};
2483 if (! defined $self->{cond}) {
2484 # just massage $data below
2486 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2487 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2488 @cols_from_relations = keys %new_data;
2490 elsif (ref $self->{cond} ne 'HASH') {
2491 $self->throw_exception(
2492 "Can't abstract implicit construct, resultset condition not a hash"
2496 # precendence must be given to passed values over values inherited from
2497 # the cond, so the order here is important.
2498 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2499 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2501 while ( my($col, $value) = each %implied ) {
2502 my $vref = ref $value;
2508 (keys %$value)[0] eq '='
2510 $new_data{$col} = $value->{'='};
2512 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2513 $new_data{$col} = $value;
2520 %{ $self->_remove_alias($data, $alias) },
2523 return (\%new_data, \@cols_from_relations);
2526 # _has_resolved_attr
2528 # determines if the resultset defines at least one
2529 # of the attributes supplied
2531 # used to determine if a subquery is neccessary
2533 # supports some virtual attributes:
2535 # This will scan for any joins being present on the resultset.
2536 # It is not a mere key-search but a deep inspection of {from}
2539 sub _has_resolved_attr {
2540 my ($self, @attr_names) = @_;
2542 my $attrs = $self->_resolved_attrs;
2546 for my $n (@attr_names) {
2547 if (grep { $n eq $_ } (qw/-join/) ) {
2548 $extra_checks{$n}++;
2552 my $attr = $attrs->{$n};
2554 next if not defined $attr;
2556 if (ref $attr eq 'HASH') {
2557 return 1 if keys %$attr;
2559 elsif (ref $attr eq 'ARRAY') {
2567 # a resolved join is expressed as a multi-level from
2569 $extra_checks{-join}
2571 ref $attrs->{from} eq 'ARRAY'
2573 @{$attrs->{from}} > 1
2581 # Recursively collapse the condition.
2583 sub _collapse_cond {
2584 my ($self, $cond, $collapsed) = @_;
2588 if (ref $cond eq 'ARRAY') {
2589 foreach my $subcond (@$cond) {
2590 next unless ref $subcond; # -or
2591 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2594 elsif (ref $cond eq 'HASH') {
2595 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2596 foreach my $subcond (@{$cond->{-and}}) {
2597 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2601 foreach my $col (keys %$cond) {
2602 my $value = $cond->{$col};
2603 $collapsed->{$col} = $value;
2613 # Remove the specified alias from the specified query hash. A copy is made so
2614 # the original query is not modified.
2617 my ($self, $query, $alias) = @_;
2619 my %orig = %{ $query || {} };
2622 foreach my $key (keys %orig) {
2624 $unaliased{$key} = $orig{$key};
2627 $unaliased{$1} = $orig{$key}
2628 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2638 =item Arguments: none
2640 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2644 Returns the SQL query and bind vars associated with the invocant.
2646 This is generally used as the RHS for a subquery.
2653 my $attrs = { %{ $self->_resolved_attrs } };
2655 my $aq = $self->result_source->storage->_select_args_to_query (
2656 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2659 $self->{_attrs}{_sqlmaker_select_args} = $attrs->{_sqlmaker_select_args};
2668 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2670 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2674 my $artist = $schema->resultset('Artist')->find_or_new(
2675 { artist => 'fred' }, { key => 'artists' });
2677 $cd->cd_to_producer->find_or_new({ producer => $producer },
2678 { key => 'primary });
2680 Find an existing record from this resultset using L</find>. if none exists,
2681 instantiate a new result object and return it. The object will not be saved
2682 into your storage until you call L<DBIx::Class::Row/insert> on it.
2684 You most likely want this method when looking for existing rows using a unique
2685 constraint that is not the primary key, or looking for related rows.
2687 If you want objects to be saved immediately, use L</find_or_create> instead.
2689 B<Note>: Make sure to read the documentation of L</find> and understand the
2690 significance of the C<key> attribute, as its lack may skew your search, and
2691 subsequently result in spurious new objects.
2693 B<Note>: Take care when using C<find_or_new> with a table having
2694 columns with default values that you intend to be automatically
2695 supplied by the database (e.g. an auto_increment primary key column).
2696 In normal usage, the value of such columns should NOT be included at
2697 all in the call to C<find_or_new>, even when set to C<undef>.
2703 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2704 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2705 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2708 return $self->new_result($hash);
2715 =item Arguments: \%col_data
2717 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2721 Attempt to create a single new row or a row with multiple related rows
2722 in the table represented by the resultset (and related tables). This
2723 will not check for duplicate rows before inserting, use
2724 L</find_or_create> to do that.
2726 To create one row for this resultset, pass a hashref of key/value
2727 pairs representing the columns of the table and the values you wish to
2728 store. If the appropriate relationships are set up, foreign key fields
2729 can also be passed an object representing the foreign row, and the
2730 value will be set to its primary key.
2732 To create related objects, pass a hashref of related-object column values
2733 B<keyed on the relationship name>. If the relationship is of type C<multi>
2734 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2735 The process will correctly identify columns holding foreign keys, and will
2736 transparently populate them from the keys of the corresponding relation.
2737 This can be applied recursively, and will work correctly for a structure
2738 with an arbitrary depth and width, as long as the relationships actually
2739 exists and the correct column data has been supplied.
2741 Instead of hashrefs of plain related data (key/value pairs), you may
2742 also pass new or inserted objects. New objects (not inserted yet, see
2743 L</new_result>), will be inserted into their appropriate tables.
2745 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2747 Example of creating a new row.
2749 $person_rs->create({
2750 name=>"Some Person",
2751 email=>"somebody@someplace.com"
2754 Example of creating a new row and also creating rows in a related C<has_many>
2755 or C<has_one> resultset. Note Arrayref.
2758 { artistid => 4, name => 'Manufactured Crap', cds => [
2759 { title => 'My First CD', year => 2006 },
2760 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2765 Example of creating a new row and also creating a row in a related
2766 C<belongs_to> resultset. Note Hashref.
2769 title=>"Music for Silly Walks",
2772 name=>"Silly Musician",
2780 When subclassing ResultSet never attempt to override this method. Since
2781 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2782 lot of the internals simply never call it, so your override will be
2783 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2784 or L<DBIx::Class::Row/insert> depending on how early in the
2785 L</create> process you need to intervene. See also warning pertaining to
2793 my ($self, $col_data) = @_;
2794 $self->throw_exception( "create needs a hashref" )
2795 unless ref $col_data eq 'HASH';
2796 return $self->new_result($col_data)->insert;
2799 =head2 find_or_create
2803 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2805 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2809 $cd->cd_to_producer->find_or_create({ producer => $producer },
2810 { key => 'primary' });
2812 Tries to find a record based on its primary key or unique constraints; if none
2813 is found, creates one and returns that instead.
2815 my $cd = $schema->resultset('CD')->find_or_create({
2817 artist => 'Massive Attack',
2818 title => 'Mezzanine',
2822 Also takes an optional C<key> attribute, to search by a specific key or unique
2823 constraint. For example:
2825 my $cd = $schema->resultset('CD')->find_or_create(
2827 artist => 'Massive Attack',
2828 title => 'Mezzanine',
2830 { key => 'cd_artist_title' }
2833 B<Note>: Make sure to read the documentation of L</find> and understand the
2834 significance of the C<key> attribute, as its lack may skew your search, and
2835 subsequently result in spurious row creation.
2837 B<Note>: Because find_or_create() reads from the database and then
2838 possibly inserts based on the result, this method is subject to a race
2839 condition. Another process could create a record in the table after
2840 the find has completed and before the create has started. To avoid
2841 this problem, use find_or_create() inside a transaction.
2843 B<Note>: Take care when using C<find_or_create> with a table having
2844 columns with default values that you intend to be automatically
2845 supplied by the database (e.g. an auto_increment primary key column).
2846 In normal usage, the value of such columns should NOT be included at
2847 all in the call to C<find_or_create>, even when set to C<undef>.
2849 See also L</find> and L</update_or_create>. For information on how to declare
2850 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2852 If you need to know if an existing row was found or a new one created use
2853 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2854 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2857 my $cd = $schema->resultset('CD')->find_or_new({
2859 artist => 'Massive Attack',
2860 title => 'Mezzanine',
2864 if( !$cd->in_storage ) {
2871 sub find_or_create {
2873 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2874 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2875 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2878 return $self->create($hash);
2881 =head2 update_or_create
2885 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2887 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2891 $resultset->update_or_create({ col => $val, ... });
2893 Like L</find_or_create>, but if a row is found it is immediately updated via
2894 C<< $found_row->update (\%col_data) >>.
2897 Takes an optional C<key> attribute to search on a specific unique constraint.
2900 # In your application
2901 my $cd = $schema->resultset('CD')->update_or_create(
2903 artist => 'Massive Attack',
2904 title => 'Mezzanine',
2907 { key => 'cd_artist_title' }
2910 $cd->cd_to_producer->update_or_create({
2911 producer => $producer,
2917 B<Note>: Make sure to read the documentation of L</find> and understand the
2918 significance of the C<key> attribute, as its lack may skew your search, and
2919 subsequently result in spurious row creation.
2921 B<Note>: Take care when using C<update_or_create> with a table having
2922 columns with default values that you intend to be automatically
2923 supplied by the database (e.g. an auto_increment primary key column).
2924 In normal usage, the value of such columns should NOT be included at
2925 all in the call to C<update_or_create>, even when set to C<undef>.
2927 See also L</find> and L</find_or_create>. For information on how to declare
2928 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2930 If you need to know if an existing row was updated or a new one created use
2931 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2932 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2937 sub update_or_create {
2939 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2940 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2942 my $row = $self->find($cond, $attrs);
2944 $row->update($cond);
2948 return $self->create($cond);
2951 =head2 update_or_new
2955 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2957 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2961 $resultset->update_or_new({ col => $val, ... });
2963 Like L</find_or_new> but if a row is found it is immediately updated via
2964 C<< $found_row->update (\%col_data) >>.
2968 # In your application
2969 my $cd = $schema->resultset('CD')->update_or_new(
2971 artist => 'Massive Attack',
2972 title => 'Mezzanine',
2975 { key => 'cd_artist_title' }
2978 if ($cd->in_storage) {
2979 # the cd was updated
2982 # the cd is not yet in the database, let's insert it
2986 B<Note>: Make sure to read the documentation of L</find> and understand the
2987 significance of the C<key> attribute, as its lack may skew your search, and
2988 subsequently result in spurious new objects.
2990 B<Note>: Take care when using C<update_or_new> with a table having
2991 columns with default values that you intend to be automatically
2992 supplied by the database (e.g. an auto_increment primary key column).
2993 In normal usage, the value of such columns should NOT be included at
2994 all in the call to C<update_or_new>, even when set to C<undef>.
2996 See also L</find>, L</find_or_create> and L</find_or_new>.
3002 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
3003 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
3005 my $row = $self->find( $cond, $attrs );
3006 if ( defined $row ) {
3007 $row->update($cond);
3011 return $self->new_result($cond);
3018 =item Arguments: none
3020 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
3024 Gets the contents of the cache for the resultset, if the cache is set.
3026 The cache is populated either by using the L</prefetch> attribute to
3027 L</search> or by calling L</set_cache>.
3039 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3041 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3045 Sets the contents of the cache for the resultset. Expects an arrayref
3046 of objects of the same class as those produced by the resultset. Note that
3047 if the cache is set, the resultset will return the cached objects rather
3048 than re-querying the database even if the cache attr is not set.
3050 The contents of the cache can also be populated by using the
3051 L</prefetch> attribute to L</search>.
3056 my ( $self, $data ) = @_;
3057 $self->throw_exception("set_cache requires an arrayref")
3058 if defined($data) && (ref $data ne 'ARRAY');
3059 $self->{all_cache} = $data;
3066 =item Arguments: none
3068 =item Return Value: undef
3072 Clears the cache for the resultset.
3077 shift->set_cache(undef);
3084 =item Arguments: none
3086 =item Return Value: true, if the resultset has been paginated
3094 return !!$self->{attrs}{page};
3101 =item Arguments: none
3103 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3111 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3114 =head2 related_resultset
3118 =item Arguments: $rel_name
3120 =item Return Value: L<$resultset|/search>
3124 Returns a related resultset for the supplied relationship name.
3126 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3130 sub related_resultset {
3131 my ($self, $rel) = @_;
3133 return $self->{related_resultsets}{$rel}
3134 if defined $self->{related_resultsets}{$rel};
3136 return $self->{related_resultsets}{$rel} = do {
3137 my $rsrc = $self->result_source;
3138 my $rel_info = $rsrc->relationship_info($rel);
3140 $self->throw_exception(
3141 "search_related: result source '" . $rsrc->source_name .
3142 "' has no such relationship $rel")
3145 my $attrs = $self->_chain_relationship($rel);
3147 my $join_count = $attrs->{seen_join}{$rel};
3149 my $alias = $self->result_source->storage
3150 ->relname_to_table_alias($rel, $join_count);
3152 # since this is search_related, and we already slid the select window inwards
3153 # (the select/as attrs were deleted in the beginning), we need to flip all
3154 # left joins to inner, so we get the expected results
3155 # read the comment on top of the actual function to see what this does
3156 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3159 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3160 delete @{$attrs}{qw(result_class alias)};
3164 if (my $cache = $self->get_cache) {
3165 $related_cache = [ map
3166 { @{$_->related_resultset($rel)->get_cache||[]} }
3171 my $rel_source = $rsrc->related_source($rel);
3175 # The reason we do this now instead of passing the alias to the
3176 # search_rs below is that if you wrap/overload resultset on the
3177 # source you need to know what alias it's -going- to have for things
3178 # to work sanely (e.g. RestrictWithObject wants to be able to add
3179 # extra query restrictions, and these may need to be $alias.)
3181 my $rel_attrs = $rel_source->resultset_attributes;
3182 local $rel_attrs->{alias} = $alias;
3184 $rel_source->resultset
3188 where => $attrs->{where},
3191 $new->set_cache($related_cache) if $related_cache;
3196 =head2 current_source_alias
3200 =item Arguments: none
3202 =item Return Value: $source_alias
3206 Returns the current table alias for the result source this resultset is built
3207 on, that will be used in the SQL query. Usually it is C<me>.
3209 Currently the source alias that refers to the result set returned by a
3210 L</search>/L</find> family method depends on how you got to the resultset: it's
3211 C<me> by default, but eg. L</search_related> aliases it to the related result
3212 source name (and keeps C<me> referring to the original result set). The long
3213 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3214 (and make this method unnecessary).
3216 Thus it's currently necessary to use this method in predefined queries (see
3217 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3218 source alias of the current result set:
3220 # in a result set class
3222 my ($self, $user) = @_;
3224 my $me = $self->current_source_alias;
3226 return $self->search({
3227 "$me.modified" => $user->id,
3233 sub current_source_alias {
3234 return (shift->{attrs} || {})->{alias} || 'me';
3237 =head2 as_subselect_rs
3241 =item Arguments: none
3243 =item Return Value: L<$resultset|/search>
3247 Act as a barrier to SQL symbols. The resultset provided will be made into a
3248 "virtual view" by including it as a subquery within the from clause. From this
3249 point on, any joined tables are inaccessible to ->search on the resultset (as if
3250 it were simply where-filtered without joins). For example:
3252 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3254 # 'x' now pollutes the query namespace
3256 # So the following works as expected
3257 my $ok_rs = $rs->search({'x.other' => 1});
3259 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3260 # def) we look for one row with contradictory terms and join in another table
3261 # (aliased 'x_2') which we never use
3262 my $broken_rs = $rs->search({'x.name' => 'def'});
3264 my $rs2 = $rs->as_subselect_rs;
3266 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3267 my $not_joined_rs = $rs2->search({'x.other' => 1});
3269 # works as expected: finds a 'table' row related to two x rows (abc and def)
3270 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3272 Another example of when one might use this would be to select a subset of
3273 columns in a group by clause:
3275 my $rs = $schema->resultset('Bar')->search(undef, {
3276 group_by => [qw{ id foo_id baz_id }],
3277 })->as_subselect_rs->search(undef, {
3278 columns => [qw{ id foo_id }]
3281 In the above example normally columns would have to be equal to the group by,
3282 but because we isolated the group by into a subselect the above works.
3286 sub as_subselect_rs {
3289 my $attrs = $self->_resolved_attrs;
3291 my $fresh_rs = (ref $self)->new (
3292 $self->result_source
3295 # these pieces will be locked in the subquery
3296 delete $fresh_rs->{cond};
3297 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3299 return $fresh_rs->search( {}, {
3301 $attrs->{alias} => $self->as_query,
3302 -alias => $attrs->{alias},
3303 -rsrc => $self->result_source,
3305 alias => $attrs->{alias},
3309 # This code is called by search_related, and makes sure there
3310 # is clear separation between the joins before, during, and
3311 # after the relationship. This information is needed later
3312 # in order to properly resolve prefetch aliases (any alias
3313 # with a relation_chain_depth less than the depth of the
3314 # current prefetch is not considered)
3316 # The increments happen twice per join. An even number means a
3317 # relationship specified via a search_related, whereas an odd
3318 # number indicates a join/prefetch added via attributes
3320 # Also this code will wrap the current resultset (the one we
3321 # chain to) in a subselect IFF it contains limiting attributes
3322 sub _chain_relationship {
3323 my ($self, $rel) = @_;
3324 my $source = $self->result_source;
3325 my $attrs = { %{$self->{attrs}||{}} };
3327 # we need to take the prefetch the attrs into account before we
3328 # ->_resolve_join as otherwise they get lost - captainL
3329 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3331 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3333 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3336 my @force_subq_attrs = qw/offset rows group_by having/;
3339 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3341 $self->_has_resolved_attr (@force_subq_attrs)
3343 # Nuke the prefetch (if any) before the new $rs attrs
3344 # are resolved (prefetch is useless - we are wrapping
3345 # a subquery anyway).
3346 my $rs_copy = $self->search;
3347 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3348 $rs_copy->{attrs}{join},
3349 delete $rs_copy->{attrs}{prefetch},
3354 -alias => $attrs->{alias},
3355 $attrs->{alias} => $rs_copy->as_query,
3357 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3358 $seen->{-relation_chain_depth} = 0;
3360 elsif ($attrs->{from}) { #shallow copy suffices
3361 $from = [ @{$attrs->{from}} ];
3366 -alias => $attrs->{alias},
3367 $attrs->{alias} => $source->from,
3371 my $jpath = ($seen->{-relation_chain_depth})
3372 ? $from->[-1][0]{-join_path}
3375 my @requested_joins = $source->_resolve_join(
3382 push @$from, @requested_joins;
3384 $seen->{-relation_chain_depth}++;
3386 # if $self already had a join/prefetch specified on it, the requested
3387 # $rel might very well be already included. What we do in this case
3388 # is effectively a no-op (except that we bump up the chain_depth on
3389 # the join in question so we could tell it *is* the search_related)
3392 # we consider the last one thus reverse
3393 for my $j (reverse @requested_joins) {
3394 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3395 if ($rel eq $last_j) {
3396 $j->[0]{-relation_chain_depth}++;
3402 unless ($already_joined) {
3403 push @$from, $source->_resolve_join(
3411 $seen->{-relation_chain_depth}++;
3413 return {%$attrs, from => $from, seen_join => $seen};
3416 sub _resolved_attrs {
3418 return $self->{_attrs} if $self->{_attrs};
3420 my $attrs = { %{ $self->{attrs} || {} } };
3421 my $source = $self->result_source;
3422 my $alias = $attrs->{alias};
3424 # default selection list
3425 $attrs->{columns} = [ $source->columns ]
3426 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3428 # merge selectors together
3429 for (qw/columns select as/) {
3430 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3431 if $attrs->{$_} or $attrs->{"+$_"};
3434 # disassemble columns
3436 if (my $cols = delete $attrs->{columns}) {
3437 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3438 if (ref $c eq 'HASH') {
3439 for my $as (sort keys %$c) {
3440 push @sel, $c->{$as};
3451 # when trying to weed off duplicates later do not go past this point -
3452 # everything added from here on is unbalanced "anyone's guess" stuff
3453 my $dedup_stop_idx = $#as;
3455 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3457 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3458 if $attrs->{select};
3460 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3461 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3463 # disqualify all $alias.col as-bits (inflate-map mandated)
3464 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3466 # de-duplicate the result (remove *identical* select/as pairs)
3467 # and also die on duplicate {as} pointing to different {select}s
3468 # not using a c-style for as the condition is prone to shrinkage
3471 while ($i <= $dedup_stop_idx) {
3472 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3477 elsif ($seen->{$as[$i]}++) {
3478 $self->throw_exception(
3479 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3487 $attrs->{select} = \@sel;
3488 $attrs->{as} = \@as;
3490 $attrs->{from} ||= [{
3492 -alias => $self->{attrs}{alias},
3493 $self->{attrs}{alias} => $source->from,
3496 if ( $attrs->{join} || $attrs->{prefetch} ) {
3498 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3499 if ref $attrs->{from} ne 'ARRAY';
3501 my $join = (delete $attrs->{join}) || {};
3503 if ( defined $attrs->{prefetch} ) {
3504 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3507 $attrs->{from} = # have to copy here to avoid corrupting the original
3509 @{ $attrs->{from} },
3510 $source->_resolve_join(
3513 { %{ $attrs->{seen_join} || {} } },
3514 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3515 ? $attrs->{from}[-1][0]{-join_path}
3522 if ( defined $attrs->{order_by} ) {
3523 $attrs->{order_by} = (
3524 ref( $attrs->{order_by} ) eq 'ARRAY'
3525 ? [ @{ $attrs->{order_by} } ]
3526 : [ $attrs->{order_by} || () ]
3530 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3531 $attrs->{group_by} = [ $attrs->{group_by} ];
3534 # generate the distinct induced group_by early, as prefetch will be carried via a
3535 # subquery (since a group_by is present)
3536 if (delete $attrs->{distinct}) {
3537 if ($attrs->{group_by}) {
3538 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3541 $attrs->{_grouped_by_distinct} = 1;
3542 # distinct affects only the main selection part, not what prefetch may
3544 $attrs->{group_by} = $source->storage->_group_over_selection($attrs);
3548 # generate selections based on the prefetch helper
3550 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3551 if defined $attrs->{prefetch};
3555 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3556 if $attrs->{_dark_selector};
3558 $attrs->{collapse} = 1;
3560 # this is a separate structure (we don't look in {from} directly)
3561 # as the resolver needs to shift things off the lists to work
3562 # properly (identical-prefetches on different branches)
3564 if (ref $attrs->{from} eq 'ARRAY') {
3566 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3568 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3569 next unless $j->[0]{-alias};
3570 next unless $j->[0]{-join_path};
3571 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3573 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3576 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3577 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3581 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3583 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3584 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3587 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3588 $attrs->{_related_results_construction} = 1;
3591 # run through the resulting joinstructure (starting from our current slot)
3592 # and unset collapse if proven unnesessary
3594 # also while we are at it find out if the current root source has
3595 # been premultiplied by previous related_source chaining
3597 # this allows to predict whether a root object with all other relation
3598 # data set to NULL is in fact unique
3599 if ($attrs->{collapse}) {
3601 if (ref $attrs->{from} eq 'ARRAY') {
3603 if (@{$attrs->{from}} == 1) {
3604 # no joins - no collapse
3605 $attrs->{collapse} = 0;
3608 # find where our table-spec starts
3609 my @fromlist = @{$attrs->{from}};
3611 my $t = shift @fromlist;
3614 # me vs join from-spec distinction - a ref means non-root
3615 if (ref $t eq 'ARRAY') {
3617 $is_multi ||= ! $t->{-is_single};
3619 last if ($t->{-alias} && $t->{-alias} eq $alias);
3620 $attrs->{_main_source_premultiplied} ||= $is_multi;
3623 # no non-singles remaining, nor any premultiplication - nothing to collapse
3625 ! $attrs->{_main_source_premultiplied}
3627 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3629 $attrs->{collapse} = 0;
3635 # if we can not analyze the from - err on the side of safety
3636 $attrs->{_main_source_premultiplied} = 1;
3640 # if both page and offset are specified, produce a combined offset
3641 # even though it doesn't make much sense, this is what pre 081xx has
3643 if (my $page = delete $attrs->{page}) {
3645 ($attrs->{rows} * ($page - 1))
3647 ($attrs->{offset} || 0)
3651 return $self->{_attrs} = $attrs;
3655 my ($self, $attr) = @_;
3657 if (ref $attr eq 'HASH') {
3658 return $self->_rollout_hash($attr);
3659 } elsif (ref $attr eq 'ARRAY') {
3660 return $self->_rollout_array($attr);
3666 sub _rollout_array {
3667 my ($self, $attr) = @_;
3670 foreach my $element (@{$attr}) {
3671 if (ref $element eq 'HASH') {
3672 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3673 } elsif (ref $element eq 'ARRAY') {
3674 # XXX - should probably recurse here
3675 push( @rolled_array, @{$self->_rollout_array($element)} );
3677 push( @rolled_array, $element );
3680 return \@rolled_array;
3684 my ($self, $attr) = @_;
3687 foreach my $key (keys %{$attr}) {
3688 push( @rolled_array, { $key => $attr->{$key} } );
3690 return \@rolled_array;
3693 sub _calculate_score {
3694 my ($self, $a, $b) = @_;
3696 if (defined $a xor defined $b) {
3699 elsif (not defined $a) {
3703 if (ref $b eq 'HASH') {
3704 my ($b_key) = keys %{$b};
3705 if (ref $a eq 'HASH') {
3706 my ($a_key) = keys %{$a};
3707 if ($a_key eq $b_key) {
3708 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3713 return ($a eq $b_key) ? 1 : 0;
3716 if (ref $a eq 'HASH') {
3717 my ($a_key) = keys %{$a};
3718 return ($b eq $a_key) ? 1 : 0;
3720 return ($b eq $a) ? 1 : 0;
3725 sub _merge_joinpref_attr {
3726 my ($self, $orig, $import) = @_;
3728 return $import unless defined($orig);
3729 return $orig unless defined($import);
3731 $orig = $self->_rollout_attr($orig);
3732 $import = $self->_rollout_attr($import);
3735 foreach my $import_element ( @{$import} ) {
3736 # find best candidate from $orig to merge $b_element into
3737 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3738 foreach my $orig_element ( @{$orig} ) {
3739 my $score = $self->_calculate_score( $orig_element, $import_element );
3740 if ($score > $best_candidate->{score}) {
3741 $best_candidate->{position} = $position;
3742 $best_candidate->{score} = $score;
3746 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3747 $import_key = '' if not defined $import_key;
3749 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3750 push( @{$orig}, $import_element );
3752 my $orig_best = $orig->[$best_candidate->{position}];
3753 # merge orig_best and b_element together and replace original with merged
3754 if (ref $orig_best ne 'HASH') {
3755 $orig->[$best_candidate->{position}] = $import_element;
3756 } elsif (ref $import_element eq 'HASH') {
3757 my ($key) = keys %{$orig_best};
3758 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3761 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3764 return @$orig ? $orig : ();
3772 require Hash::Merge;
3773 my $hm = Hash::Merge->new;
3775 $hm->specify_behavior({
3778 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3780 if ($defl xor $defr) {
3781 return [ $defl ? $_[0] : $_[1] ];
3786 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3790 return [$_[0], $_[1]];
3794 return $_[1] if !defined $_[0];
3795 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3796 return [$_[0], @{$_[1]}]
3799 return [] if !defined $_[0] and !keys %{$_[1]};
3800 return [ $_[1] ] if !defined $_[0];
3801 return [ $_[0] ] if !keys %{$_[1]};
3802 return [$_[0], $_[1]]
3807 return $_[0] if !defined $_[1];
3808 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3809 return [@{$_[0]}, $_[1]]
3812 my @ret = @{$_[0]} or return $_[1];
3813 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3814 my %idx = map { $_ => 1 } @ret;
3815 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3819 return [ $_[1] ] if ! @{$_[0]};
3820 return $_[0] if !keys %{$_[1]};
3821 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3822 return [ @{$_[0]}, $_[1] ];
3827 return [] if !keys %{$_[0]} and !defined $_[1];
3828 return [ $_[0] ] if !defined $_[1];
3829 return [ $_[1] ] if !keys %{$_[0]};
3830 return [$_[0], $_[1]]
3833 return [] if !keys %{$_[0]} and !@{$_[1]};
3834 return [ $_[0] ] if !@{$_[1]};
3835 return $_[1] if !keys %{$_[0]};
3836 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3837 return [ $_[0], @{$_[1]} ];
3840 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3841 return [ $_[0] ] if !keys %{$_[1]};
3842 return [ $_[1] ] if !keys %{$_[0]};
3843 return [ $_[0] ] if $_[0] eq $_[1];
3844 return [ $_[0], $_[1] ];
3847 } => 'DBIC_RS_ATTR_MERGER');
3851 return $hm->merge ($_[1], $_[2]);
3855 sub STORABLE_freeze {
3856 my ($self, $cloning) = @_;
3857 my $to_serialize = { %$self };
3859 # A cursor in progress can't be serialized (and would make little sense anyway)
3860 # the parser can be regenerated (and can't be serialized)
3861 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3863 # nor is it sensical to store a not-yet-fired-count pager
3864 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3865 delete $to_serialize->{pager};
3868 Storable::nfreeze($to_serialize);
3871 # need this hook for symmetry
3873 my ($self, $cloning, $serialized) = @_;
3875 %$self = %{ Storable::thaw($serialized) };
3881 =head2 throw_exception
3883 See L<DBIx::Class::Schema/throw_exception> for details.
3887 sub throw_exception {
3890 if (ref $self and my $rsrc = $self->result_source) {
3891 $rsrc->throw_exception(@_)
3894 DBIx::Class::Exception->throw(@_);
3902 # XXX: FIXME: Attributes docs need clearing up
3906 Attributes are used to refine a ResultSet in various ways when
3907 searching for data. They can be passed to any method which takes an
3908 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3911 Default attributes can be set on the result class using
3912 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3913 the CAVEATS on that feature before using it!)
3915 These are in no particular order:
3921 =item Value: ( $order_by | \@order_by | \%order_by )
3925 Which column(s) to order the results by.
3927 [The full list of suitable values is documented in
3928 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3931 If a single column name, or an arrayref of names is supplied, the
3932 argument is passed through directly to SQL. The hashref syntax allows
3933 for connection-agnostic specification of ordering direction:
3935 For descending order:
3937 order_by => { -desc => [qw/col1 col2 col3/] }
3939 For explicit ascending order:
3941 order_by => { -asc => 'col' }
3943 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3944 supported, although you are strongly encouraged to use the hashref
3945 syntax as outlined above.
3951 =item Value: \@columns | \%columns | $column
3955 Shortcut to request a particular set of columns to be retrieved. Each
3956 column spec may be a string (a table column name), or a hash (in which
3957 case the key is the C<as> value, and the value is used as the C<select>
3958 expression). Adds C<me.> onto the start of any column without a C<.> in
3959 it and sets C<select> from that, then auto-populates C<as> from
3960 C<select> as normal. (You may also use the C<cols> attribute, as in
3961 earlier versions of DBIC, but this is deprecated.)
3963 Essentially C<columns> does the same as L</select> and L</as>.
3965 columns => [ 'foo', { bar => 'baz' } ]
3969 select => [qw/foo baz/],
3976 =item Value: \@columns
3980 Indicates additional columns to be selected from storage. Works the same as
3981 L</columns> but adds columns to the selection. (You may also use the
3982 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3983 deprecated). For example:-
3985 $schema->resultset('CD')->search(undef, {
3986 '+columns' => ['artist.name'],
3990 would return all CDs and include a 'name' column to the information
3991 passed to object inflation. Note that the 'artist' is the name of the
3992 column (or relationship) accessor, and 'name' is the name of the column
3993 accessor in the related table.
3995 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3996 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3997 unary plus operator before it.
3999 =head2 include_columns
4003 =item Value: \@columns
4007 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
4013 =item Value: \@select_columns
4017 Indicates which columns should be selected from the storage. You can use
4018 column names, or in the case of RDBMS back ends, function or stored procedure
4021 $rs = $schema->resultset('Employee')->search(undef, {
4024 { count => 'employeeid' },
4025 { max => { length => 'name' }, -as => 'longest_name' }
4030 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
4032 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
4033 use L</select>, to instruct DBIx::Class how to store the result of the column.
4034 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
4035 identifier aliasing. You can however alias a function, so you can use it in
4036 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
4037 attribute> supplied as shown in the example above.
4039 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
4040 Not doing so causes Perl to incorrectly interpret them as a bareword with a
4041 unary plus operator before it.
4047 Indicates additional columns to be selected from storage. Works the same as
4048 L</select> but adds columns to the default selection, instead of specifying
4057 =item Value: \@inflation_names
4061 Indicates column names for object inflation. That is L</as> indicates the
4062 slot name in which the column value will be stored within the
4063 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4064 identifier by the C<get_column> method (or via the object accessor B<if one
4065 with the same name already exists>) as shown below. The L</as> attribute has
4066 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4068 $rs = $schema->resultset('Employee')->search(undef, {
4071 { count => 'employeeid' },
4072 { max => { length => 'name' }, -as => 'longest_name' }
4081 If the object against which the search is performed already has an accessor
4082 matching a column name specified in C<as>, the value can be retrieved using
4083 the accessor as normal:
4085 my $name = $employee->name();
4087 If on the other hand an accessor does not exist in the object, you need to
4088 use C<get_column> instead:
4090 my $employee_count = $employee->get_column('employee_count');
4092 You can create your own accessors if required - see
4093 L<DBIx::Class::Manual::Cookbook> for details.
4099 Indicates additional column names for those added via L</+select>. See L</as>.
4107 =item Value: ($rel_name | \@rel_names | \%rel_names)
4111 Contains a list of relationships that should be joined for this query. For
4114 # Get CDs by Nine Inch Nails
4115 my $rs = $schema->resultset('CD')->search(
4116 { 'artist.name' => 'Nine Inch Nails' },
4117 { join => 'artist' }
4120 Can also contain a hash reference to refer to the other relation's relations.
4123 package MyApp::Schema::Track;
4124 use base qw/DBIx::Class/;
4125 __PACKAGE__->table('track');
4126 __PACKAGE__->add_columns(qw/trackid cd position title/);
4127 __PACKAGE__->set_primary_key('trackid');
4128 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4131 # In your application
4132 my $rs = $schema->resultset('Artist')->search(
4133 { 'track.title' => 'Teardrop' },
4135 join => { cd => 'track' },
4136 order_by => 'artist.name',
4140 You need to use the relationship (not the table) name in conditions,
4141 because they are aliased as such. The current table is aliased as "me", so
4142 you need to use me.column_name in order to avoid ambiguity. For example:
4144 # Get CDs from 1984 with a 'Foo' track
4145 my $rs = $schema->resultset('CD')->search(
4148 'tracks.name' => 'Foo'
4150 { join => 'tracks' }
4153 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4154 similarly for a third time). For e.g.
4156 my $rs = $schema->resultset('Artist')->search({
4157 'cds.title' => 'Down to Earth',
4158 'cds_2.title' => 'Popular',
4160 join => [ qw/cds cds/ ],
4163 will return a set of all artists that have both a cd with title 'Down
4164 to Earth' and a cd with title 'Popular'.
4166 If you want to fetch related objects from other tables as well, see L</prefetch>
4169 NOTE: An internal join-chain pruner will discard certain joins while
4170 constructing the actual SQL query, as long as the joins in question do not
4171 affect the retrieved result. This for example includes 1:1 left joins
4172 that are not part of the restriction specification (WHERE/HAVING) nor are
4173 a part of the query selection.
4175 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4181 =item Value: (0 | 1)
4185 When set to a true value, indicates that any rows fetched from joined has_many
4186 relationships are to be aggregated into the corresponding "parent" object. For
4187 example, the resultset:
4189 my $rs = $schema->resultset('CD')->search({}, {
4190 '+columns' => [ qw/ tracks.title tracks.position / ],
4195 While executing the following query:
4197 SELECT me.*, tracks.title, tracks.position
4199 LEFT JOIN track tracks
4200 ON tracks.cdid = me.cdid
4202 Will return only as many objects as there are rows in the CD source, even
4203 though the result of the query may span many rows. Each of these CD objects
4204 will in turn have multiple "Track" objects hidden behind the has_many
4205 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4206 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4207 product"), with each CD object containing exactly one of all fetched Track data.
4209 When a collapse is requested on a non-ordered resultset, an order by some
4210 unique part of the main source (the left-most table) is inserted automatically.
4211 This is done so that the resultset is allowed to be "lazy" - calling
4212 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4213 object with all of its related data.
4215 If an L</order_by> is already declared, and orders the resultset in a way that
4216 makes collapsing as described above impossible (e.g. C<< ORDER BY
4217 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4218 switch to "eager" mode and slurp the entire resultset before consturcting the
4219 first object returned by L</next>.
4221 Setting this attribute on a resultset that does not join any has_many
4222 relations is a no-op.
4224 For a more in-depth discussion, see L</PREFETCHING>.
4230 =item Value: ($rel_name | \@rel_names | \%rel_names)
4234 This attribute is a shorthand for specifying a L</join> spec, adding all
4235 columns from the joined related sources as L</+columns> and setting
4236 L</collapse> to a true value. For example, the following two queries are
4239 my $rs = $schema->resultset('Artist')->search({}, {
4240 prefetch => { cds => ['genre', 'tracks' ] },
4245 my $rs = $schema->resultset('Artist')->search({}, {
4246 join => { cds => ['genre', 'tracks' ] },
4250 { +{ "cds.$_" => "cds.$_" } }
4251 $schema->source('Artist')->related_source('cds')->columns
4254 { +{ "cds.genre.$_" => "genre.$_" } }
4255 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4258 { +{ "cds.tracks.$_" => "tracks.$_" } }
4259 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4264 Both producing the following SQL:
4266 SELECT me.artistid, me.name, me.rank, me.charfield,
4267 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4268 genre.genreid, genre.name,
4269 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4272 ON cds.artist = me.artistid
4273 LEFT JOIN genre genre
4274 ON genre.genreid = cds.genreid
4275 LEFT JOIN track tracks
4276 ON tracks.cd = cds.cdid
4277 ORDER BY me.artistid
4279 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4280 the arguments are properly merged and generally do the right thing. For
4281 example, you may want to do the following:
4283 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4284 { 'genre.genreid' => undef },
4286 join => { cds => 'genre' },
4291 Which generates the following SQL:
4293 SELECT me.artistid, me.name, me.rank, me.charfield,
4294 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4297 ON cds.artist = me.artistid
4298 LEFT JOIN genre genre
4299 ON genre.genreid = cds.genreid
4300 WHERE genre.genreid IS NULL
4301 ORDER BY me.artistid
4303 For a more in-depth discussion, see L</PREFETCHING>.
4309 =item Value: $source_alias
4313 Sets the source alias for the query. Normally, this defaults to C<me>, but
4314 nested search queries (sub-SELECTs) might need specific aliases set to
4315 reference inner queries. For example:
4318 ->related_resultset('CDs')
4319 ->related_resultset('Tracks')
4321 'track.id' => { -ident => 'none_search.id' },
4325 my $ids = $self->search({
4328 alias => 'none_search',
4329 group_by => 'none_search.id',
4330 })->get_column('id')->as_query;
4332 $self->search({ id => { -in => $ids } })
4334 This attribute is directly tied to L</current_source_alias>.
4344 Makes the resultset paged and specifies the page to retrieve. Effectively
4345 identical to creating a non-pages resultset and then calling ->page($page)
4348 If L</rows> attribute is not specified it defaults to 10 rows per page.
4350 When you have a paged resultset, L</count> will only return the number
4351 of rows in the page. To get the total, use the L</pager> and call
4352 C<total_entries> on it.
4362 Specifies the maximum number of rows for direct retrieval or the number of
4363 rows per page if the page attribute or method is used.
4369 =item Value: $offset
4373 Specifies the (zero-based) row number for the first row to be returned, or the
4374 of the first row of the first page if paging is used.
4376 =head2 software_limit
4380 =item Value: (0 | 1)
4384 When combined with L</rows> and/or L</offset> the generated SQL will not
4385 include any limit dialect stanzas. Instead the entire result will be selected
4386 as if no limits were specified, and DBIC will perform the limit locally, by
4387 artificially advancing and finishing the resulting L</cursor>.
4389 This is the recommended way of performing resultset limiting when no sane RDBMS
4390 implementation is available (e.g.
4391 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4392 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4398 =item Value: \@columns
4402 A arrayref of columns to group by. Can include columns of joined tables.
4404 group_by => [qw/ column1 column2 ... /]
4410 =item Value: $condition
4414 HAVING is a select statement attribute that is applied between GROUP BY and
4415 ORDER BY. It is applied to the after the grouping calculations have been
4418 having => { 'count_employee' => { '>=', 100 } }
4420 or with an in-place function in which case literal SQL is required:
4422 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4428 =item Value: (0 | 1)
4432 Set to 1 to group by all columns. If the resultset already has a group_by
4433 attribute, this setting is ignored and an appropriate warning is issued.
4439 Adds to the WHERE clause.
4441 # only return rows WHERE deleted IS NULL for all searches
4442 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4444 Can be overridden by passing C<< { where => undef } >> as an attribute
4447 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4453 Set to 1 to cache search results. This prevents extra SQL queries if you
4454 revisit rows in your ResultSet:
4456 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4458 while( my $artist = $resultset->next ) {
4462 $rs->first; # without cache, this would issue a query
4464 By default, searches are not cached.
4466 For more examples of using these attributes, see
4467 L<DBIx::Class::Manual::Cookbook>.
4473 =item Value: ( 'update' | 'shared' | \$scalar )
4477 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4478 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4483 DBIx::Class supports arbitrary related data prefetching from multiple related
4484 sources. Any combination of relationship types and column sets are supported.
4485 If L<collapsing|/collapse> is requested, there is an additional requirement of
4486 selecting enough data to make every individual object uniquely identifiable.
4488 Here are some more involved examples, based on the following relationship map:
4491 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4492 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4493 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4495 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4497 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4501 my $rs = $schema->resultset('Tag')->search(
4510 The initial search results in SQL like the following:
4512 SELECT tag.*, cd.*, artist.* FROM tag
4513 JOIN cd ON tag.cd = cd.cdid
4514 JOIN artist ON cd.artist = artist.artistid
4516 L<DBIx::Class> has no need to go back to the database when we access the
4517 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4520 Simple prefetches will be joined automatically, so there is no need
4521 for a C<join> attribute in the above search.
4523 The L</prefetch> attribute can be used with any of the relationship types
4524 and multiple prefetches can be specified together. Below is a more complex
4525 example that prefetches a CD's artist, its liner notes (if present),
4526 the cover image, the tracks on that CD, and the guests on those
4529 my $rs = $schema->resultset('CD')->search(
4533 { artist => 'record_label'}, # belongs_to => belongs_to
4534 'liner_note', # might_have
4535 'cover_image', # has_one
4536 { tracks => 'guests' }, # has_many => has_many
4541 This will produce SQL like the following:
4543 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4547 ON artist.artistid = me.artistid
4548 JOIN record_label record_label
4549 ON record_label.labelid = artist.labelid
4550 LEFT JOIN track tracks
4551 ON tracks.cdid = me.cdid
4552 LEFT JOIN guest guests
4553 ON guests.trackid = track.trackid
4554 LEFT JOIN liner_notes liner_note
4555 ON liner_note.cdid = me.cdid
4556 JOIN cd_artwork cover_image
4557 ON cover_image.cdid = me.cdid
4560 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4561 C<tracks>, and C<guests> of the CD will all be available through the
4562 relationship accessors without the need for additional queries to the
4567 Prefetch does a lot of deep magic. As such, it may not behave exactly
4568 as you might expect.
4574 Prefetch uses the L</cache> to populate the prefetched relationships. This
4575 may or may not be what you want.
4579 If you specify a condition on a prefetched relationship, ONLY those
4580 rows that match the prefetched condition will be fetched into that relationship.
4581 This means that adding prefetch to a search() B<may alter> what is returned by
4582 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4584 my $artist_rs = $schema->resultset('Artist')->search({
4590 my $count = $artist_rs->first->cds->count;
4592 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4594 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4596 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4598 That cmp_ok() may or may not pass depending on the datasets involved. In other
4599 words the C<WHERE> condition would apply to the entire dataset, just like
4600 it would in regular SQL. If you want to add a condition only to the "right side"
4601 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4602 condition|DBIx::Class::Relationship::Base/condition>
4606 =head1 DBIC BIND VALUES
4608 Because DBIC may need more information to bind values than just the column name
4609 and value itself, it uses a special format for both passing and receiving bind
4610 values. Each bind value should be composed of an arrayref of
4611 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4617 If present (in any form), this is what is being passed directly to bind_param.
4618 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4619 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4621 If this is specified, all other bind options described below are ignored.
4625 If present, this is used to infer the actual bind attribute by passing to
4626 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4627 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4629 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4630 currently drivers are expected to "Do the Right Thing" when given a common
4631 datatype name. (Not ideal, but that's what we got at this point.)
4635 Currently used to correctly allocate buffers for bind_param_inout().
4636 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4637 or to a sensible value based on the "data_type".
4641 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4642 explicitly specified they are never overriden). Also used by some weird DBDs,
4643 where the column name should be available at bind_param time (e.g. Oracle).
4647 For backwards compatibility and convenience, the following shortcuts are
4650 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4651 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4652 [ undef, $val ] === [ {}, $val ]
4653 $val === [ {}, $val ]
4655 =head1 AUTHOR AND CONTRIBUTORS
4657 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4661 You may distribute this code under the same terms as Perl itself.