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
1085 $self->{_attrs}{_sqlmaker_select_args} = $attrs->{_sqlmaker_select_args};
1086 return undef unless @$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 my @extra_collapser_args;
1380 if ($attrs->{collapse} and ! $did_fetch_all ) {
1382 @extra_collapser_args = (
1383 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1384 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1385 ($self->{_stashed_rows} = []), # where does it stuff excess
1389 # hotspot - skip the setter
1390 my $res_class = $self->_result_class;
1392 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1393 $res_class->can ('inflate_result')
1394 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1397 my $infmap = $attrs->{as};
1399 $self->{_result_inflator}{is_core_row} = ( (
1402 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1403 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1405 $self->{_result_inflator}{is_hri} = ( (
1406 ! $self->{_result_inflator}{is_core_row}
1409 require DBIx::Class::ResultClass::HashRefInflator
1411 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1413 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1416 if (! $attrs->{_related_results_construction}) {
1417 # construct a much simpler array->hash folder for the one-table cases right here
1418 if ($self->{_result_inflator}{is_hri}) {
1419 for my $r (@$rows) {
1420 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1423 # FIXME SUBOPTIMAL this is a very very very hot spot
1424 # while rather optimal we can *still* do much better, by
1425 # building a smarter Row::inflate_result(), and
1426 # switch to feeding it data via a much leaner interface
1428 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1429 # this particular resultset size
1430 elsif (@$rows < 60) {
1431 for my $r (@$rows) {
1432 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1437 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1438 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1442 # Special-case multi-object HRI (we always prune, and there is no $inflator_cref pass)
1443 elsif ($self->{_result_inflator}{is_hri}) {
1445 # $args and $attrs to _mk_row_parser are seperated to delineate what is
1446 # core collapser stuff and what is dbic $rs specific
1447 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1449 inflate_map => $infmap,
1450 collapse => $attrs->{collapse},
1451 premultiplied => $attrs->{_main_source_premultiplied},
1453 prune_null_branches => 1,
1454 }, $attrs) )->($rows, @extra_collapser_args);
1456 # Regular multi-object
1458 my $parser_type = $self->{_result_inflator}{is_core_row} ? 'classic_pruning' : 'classic_nonpruning';
1460 # $args and $attrs to _mk_row_parser are seperated to delineate what is
1461 # core collapser stuff and what is dbic $rs specific
1462 ( $self->{_row_parser}{$parser_type} ||= $rsrc->_mk_row_parser({
1464 inflate_map => $infmap,
1465 collapse => $attrs->{collapse},
1466 premultiplied => $attrs->{_main_source_premultiplied},
1467 prune_null_branches => $self->{_result_inflator}{is_core_row},
1468 }, $attrs) )->($rows, @extra_collapser_args);
1470 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1473 # The @$rows check seems odd at first - why wouldn't we want to warn
1474 # regardless? The issue is things like find() etc, where the user
1475 # *knows* only one result will come back. In these cases the ->all
1476 # is not a pessimization, but rather something we actually want
1478 'Unable to properly collapse has_many results in iterator mode due '
1479 . 'to order criteria - performed an eager cursor slurp underneath. '
1480 . 'Consider using ->all() instead'
1481 ) if ( ! $fetch_all and @$rows > 1 );
1486 =head2 result_source
1490 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1492 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1496 An accessor for the primary ResultSource object from which this ResultSet
1503 =item Arguments: $result_class?
1505 =item Return Value: $result_class
1509 An accessor for the class to use when creating result objects. Defaults to
1510 C<< result_source->result_class >> - which in most cases is the name of the
1511 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1513 Note that changing the result_class will also remove any components
1514 that were originally loaded in the source class via
1515 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1516 in the original source class will not run.
1521 my ($self, $result_class) = @_;
1522 if ($result_class) {
1524 # don't fire this for an object
1525 $self->ensure_class_loaded($result_class)
1526 unless ref($result_class);
1528 if ($self->get_cache) {
1529 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1531 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1532 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1533 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1536 $self->_result_class($result_class);
1538 delete $self->{_result_inflator};
1540 $self->_result_class;
1547 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1549 =item Return Value: $count
1553 Performs an SQL C<COUNT> with the same query as the resultset was built
1554 with to find the number of elements. Passing arguments is equivalent to
1555 C<< $rs->search ($cond, \%attrs)->count >>
1561 return $self->search(@_)->count if @_ and defined $_[0];
1562 return scalar @{ $self->get_cache } if $self->get_cache;
1564 my $attrs = { %{ $self->_resolved_attrs } };
1566 # this is a little optimization - it is faster to do the limit
1567 # adjustments in software, instead of a subquery
1568 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1571 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1572 $crs = $self->_count_subq_rs ($attrs);
1575 $crs = $self->_count_rs ($attrs);
1577 my $count = $crs->next;
1579 $count -= $offset if $offset;
1580 $count = $rows if $rows and $rows < $count;
1581 $count = 0 if ($count < 0);
1590 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1592 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1596 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1597 This can be very handy for subqueries:
1599 ->search( { amount => $some_rs->count_rs->as_query } )
1601 As with regular resultsets the SQL query will be executed only after
1602 the resultset is accessed via L</next> or L</all>. That would return
1603 the same single value obtainable via L</count>.
1609 return $self->search(@_)->count_rs if @_;
1611 # this may look like a lack of abstraction (count() does about the same)
1612 # but in fact an _rs *must* use a subquery for the limits, as the
1613 # software based limiting can not be ported if this $rs is to be used
1614 # in a subquery itself (i.e. ->as_query)
1615 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1616 return $self->_count_subq_rs($self->{_attrs});
1619 return $self->_count_rs($self->{_attrs});
1624 # returns a ResultSetColumn object tied to the count query
1627 my ($self, $attrs) = @_;
1629 my $rsrc = $self->result_source;
1631 my $tmp_attrs = { %$attrs };
1632 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1633 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1635 # overwrite the selector (supplied by the storage)
1636 $rsrc->resultset_class->new($rsrc, {
1638 select => $rsrc->storage->_count_select ($rsrc, $attrs),
1640 })->get_column ('count');
1644 # same as above but uses a subquery
1646 sub _count_subq_rs {
1647 my ($self, $attrs) = @_;
1649 my $rsrc = $self->result_source;
1651 my $sub_attrs = { %$attrs };
1652 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1653 delete @{$sub_attrs}{qw/collapse columns as select order_by for/};
1655 # if we multi-prefetch we group_by something unique, as this is what we would
1656 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1657 if ( $attrs->{collapse} ) {
1658 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1659 $rsrc->_identifying_column_set || $self->throw_exception(
1660 'Unable to construct a unique group_by criteria properly collapsing the '
1661 . 'has_many prefetch before count()'
1666 # Calculate subquery selector
1667 if (my $g = $sub_attrs->{group_by}) {
1669 my $sql_maker = $rsrc->storage->sql_maker;
1671 # necessary as the group_by may refer to aliased functions
1673 for my $sel (@{$attrs->{select}}) {
1674 $sel_index->{$sel->{-as}} = $sel
1675 if (ref $sel eq 'HASH' and $sel->{-as});
1678 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1679 # also look for named aggregates referred in the having clause
1680 # having often contains scalarrefs - thus parse it out entirely
1682 if ($attrs->{having}) {
1683 local $sql_maker->{having_bind};
1684 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1685 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1686 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1687 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1688 # if we don't unset it we screw up retarded but unfortunately working
1689 # 'MAX(foo.bar)' => { '>', 3 }
1690 $sql_maker->{name_sep} = '';
1693 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1695 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1698 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1699 # and if all fails for an utterly naive quoted scalar-with-function
1700 while ($having_sql =~ /
1701 $rquote $sep $lquote (.+?) $rquote
1703 [\s,] \w+ \. (\w+) [\s,]
1705 [\s,] $lquote (.+?) $rquote [\s,]
1707 my $part = $1 || $2 || $3; # one of them matched if we got here
1708 unless ($seen_having{$part}++) {
1715 my $colpiece = $sel_index->{$_} || $_;
1717 # unqualify join-based group_by's. Arcane but possible query
1718 # also horrible horrible hack to alias a column (not a func.)
1719 # (probably need to introduce SQLA syntax)
1720 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1723 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1725 push @{$sub_attrs->{select}}, $colpiece;
1729 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1730 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1733 return $rsrc->resultset_class
1734 ->new ($rsrc, $sub_attrs)
1736 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1737 ->get_column ('count');
1741 =head2 count_literal
1743 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1744 should only be used in that context. See L</search_literal> for further info.
1748 =item Arguments: $sql_fragment, @standalone_bind_values
1750 =item Return Value: $count
1754 Counts the results in a literal query. Equivalent to calling L</search_literal>
1755 with the passed arguments, then L</count>.
1759 sub count_literal { shift->search_literal(@_)->count; }
1765 =item Arguments: none
1767 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1771 Returns all elements in the resultset.
1778 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1781 delete @{$self}{qw/_stashed_rows _stashed_results/};
1783 if (my $c = $self->get_cache) {
1787 $self->cursor->reset;
1789 my $objs = $self->_construct_results('fetch_all') || [];
1791 $self->set_cache($objs) if $self->{attrs}{cache};
1800 =item Arguments: none
1802 =item Return Value: $self
1806 Resets the resultset's cursor, so you can iterate through the elements again.
1807 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1815 delete @{$self}{qw/_stashed_rows _stashed_results/};
1816 $self->{all_cache_position} = 0;
1817 $self->cursor->reset;
1825 =item Arguments: none
1827 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1831 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1832 an object for the first result (or C<undef> if the resultset is empty).
1837 return $_[0]->reset->next;
1843 # Determines whether and what type of subquery is required for the $rs operation.
1844 # If grouping is necessary either supplies its own, or verifies the current one
1845 # After all is done delegates to the proper storage method.
1847 sub _rs_update_delete {
1848 my ($self, $op, $values) = @_;
1850 my $rsrc = $self->result_source;
1851 my $storage = $rsrc->schema->storage;
1853 my $attrs = { %{$self->_resolved_attrs} };
1855 my $join_classifications;
1856 my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
1858 # do we need a subquery for any reason?
1860 defined $existing_group_by
1862 # if {from} is unparseable wrap a subq
1863 ref($attrs->{from}) ne 'ARRAY'
1865 # limits call for a subq
1866 $self->_has_resolved_attr(qw/rows offset/)
1869 # simplify the joinmap, so we can further decide if a subq is necessary
1870 if (!$needs_subq and @{$attrs->{from}} > 1) {
1872 ($attrs->{from}, $join_classifications) =
1873 $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1875 # any non-pruneable non-local restricting joins imply subq
1876 $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
1879 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1881 (ref $attrs->{from}[0]) ne 'HASH'
1883 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1887 # do we need anything like a subquery?
1888 if (! $needs_subq) {
1889 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1890 # a condition containing 'me' or other table prefixes will not work
1891 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1893 my $sqla = $rsrc->storage->sql_maker;
1894 local $sqla->{_dequalify_idents} = 1;
1895 \[ $sqla->_recurse_where($self->{cond}) ];
1899 # we got this far - means it is time to wrap a subquery
1900 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1902 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1908 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1909 delete $attrs->{$_} for qw/select as collapse/;
1910 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1912 # this will be consumed by the pruner waaaaay down the stack
1913 $attrs->{_force_prune_multiplying_joins} = 1;
1915 my $subrs = (ref $self)->new($rsrc, $attrs);
1917 if (@$idcols == 1) {
1918 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1920 elsif ($storage->_use_multicolumn_in) {
1921 # no syntax for calling this properly yet
1922 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1923 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1924 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1929 # if all else fails - get all primary keys and operate over a ORed set
1930 # wrap in a transaction for consistency
1931 # this is where the group_by/multiplication starts to matter
1935 keys %{ $join_classifications->{multiplying} || {} }
1937 # make sure if there is a supplied group_by it matches the columns compiled above
1938 # perfectly. Anything else can not be sanely executed on most databases so croak
1939 # right then and there
1940 if ($existing_group_by) {
1941 my @current_group_by = map
1942 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1947 join ("\x00", sort @current_group_by)
1949 join ("\x00", sort @{$attrs->{columns}} )
1951 $self->throw_exception (
1952 "You have just attempted a $op operation on a resultset which does group_by"
1953 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1954 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1955 . ' kind of queries. Please retry the operation with a modified group_by or'
1956 . ' without using one at all.'
1961 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1964 $guard = $storage->txn_scope_guard;
1967 for my $row ($subrs->cursor->all) {
1969 { $idcols->[$_] => $row->[$_] }
1976 my $res = $storage->$op (
1978 $op eq 'update' ? $values : (),
1982 $guard->commit if $guard;
1991 =item Arguments: \%values
1993 =item Return Value: $underlying_storage_rv
1997 Sets the specified columns in the resultset to the supplied values in a
1998 single query. Note that this will not run any accessor/set_column/update
1999 triggers, nor will it update any result object instances derived from this
2000 resultset (this includes the contents of the L<resultset cache|/set_cache>
2001 if any). See L</update_all> if you need to execute any on-update
2002 triggers or cascades defined either by you or a
2003 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2005 The return value is a pass through of what the underlying
2006 storage backend returned, and may vary. See L<DBI/execute> for the most
2011 Note that L</update> does not process/deflate any of the values passed in.
2012 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
2013 ensure manually that any value passed to this method will stringify to
2014 something the RDBMS knows how to deal with. A notable example is the
2015 handling of L<DateTime> objects, for more info see:
2016 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
2021 my ($self, $values) = @_;
2022 $self->throw_exception('Values for update must be a hash')
2023 unless ref $values eq 'HASH';
2025 return $self->_rs_update_delete ('update', $values);
2032 =item Arguments: \%values
2034 =item Return Value: 1
2038 Fetches all objects and updates them one at a time via
2039 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2040 triggers, while L</update> will not.
2045 my ($self, $values) = @_;
2046 $self->throw_exception('Values for update_all must be a hash')
2047 unless ref $values eq 'HASH';
2049 my $guard = $self->result_source->schema->txn_scope_guard;
2050 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2059 =item Arguments: none
2061 =item Return Value: $underlying_storage_rv
2065 Deletes the rows matching this resultset in a single query. Note that this
2066 will not run any delete triggers, nor will it alter the
2067 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2068 derived from this resultset (this includes the contents of the
2069 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2070 execute any on-delete triggers or cascades defined either by you or a
2071 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2073 The return value is a pass through of what the underlying storage backend
2074 returned, and may vary. See L<DBI/execute> for the most common case.
2080 $self->throw_exception('delete does not accept any arguments')
2083 return $self->_rs_update_delete ('delete');
2090 =item Arguments: none
2092 =item Return Value: 1
2096 Fetches all objects and deletes them one at a time via
2097 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2098 triggers, while L</delete> will not.
2104 $self->throw_exception('delete_all does not accept any arguments')
2107 my $guard = $self->result_source->schema->txn_scope_guard;
2108 $_->delete for $self->all;
2117 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2119 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2123 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2130 The context of this method call has an important effect on what is
2131 submitted to storage. In void context data is fed directly to fastpath
2132 insertion routines provided by the underlying storage (most often
2133 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2134 L<insert|DBIx::Class::Row/insert> calls on the
2135 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2136 augmentation of these methods provided by components. For example if you
2137 are using something like L<DBIx::Class::UUIDColumns> to create primary
2138 keys for you, you will find that your PKs are empty. In this case you
2139 will have to explicitly force scalar or list context in order to create
2144 In non-void (scalar or list) context, this method is simply a wrapper
2145 for L</create>. Depending on list or scalar context either a list of
2146 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2147 containing these objects is returned.
2149 When supplying data in "arrayref of arrayrefs" invocation style, the
2150 first element should be a list of column names and each subsequent
2151 element should be a data value in the earlier specified column order.
2154 $Arstist_rs->populate([
2155 [ qw( artistid name ) ],
2156 [ 100, 'A Formally Unknown Singer' ],
2157 [ 101, 'A singer that jumped the shark two albums ago' ],
2158 [ 102, 'An actually cool singer' ],
2161 For the arrayref of hashrefs style each hashref should be a structure
2162 suitable for passing to L</create>. Multi-create is also permitted with
2165 $schema->resultset("Artist")->populate([
2166 { artistid => 4, name => 'Manufactured Crap', cds => [
2167 { title => 'My First CD', year => 2006 },
2168 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2171 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2172 { title => 'My parents sold me to a record company', year => 2005 },
2173 { title => 'Why Am I So Ugly?', year => 2006 },
2174 { title => 'I Got Surgery and am now Popular', year => 2007 }
2179 If you attempt a void-context multi-create as in the example above (each
2180 Artist also has the related list of CDs), and B<do not> supply the
2181 necessary autoinc foreign key information, this method will proxy to the
2182 less efficient L</create>, and then throw the Result objects away. In this
2183 case there are obviously no benefits to using this method over L</create>.
2190 # cruft placed in standalone method
2191 my $data = $self->_normalize_populate_args(@_);
2193 return unless @$data;
2195 if(defined wantarray) {
2196 my @created = map { $self->create($_) } @$data;
2197 return wantarray ? @created : \@created;
2200 my $first = $data->[0];
2202 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2203 # it relationship data
2204 my (@rels, @columns);
2205 my $rsrc = $self->result_source;
2206 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2207 for (keys %$first) {
2208 my $ref = ref $first->{$_};
2209 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2215 my @pks = $rsrc->primary_columns;
2217 ## do the belongs_to relationships
2218 foreach my $index (0..$#$data) {
2220 # delegate to create() for any dataset without primary keys with specified relationships
2221 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2223 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2224 my @ret = $self->populate($data);
2230 foreach my $rel (@rels) {
2231 next unless ref $data->[$index]->{$rel} eq "HASH";
2232 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2233 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2234 my $related = $result->result_source->_resolve_condition(
2235 $reverse_relinfo->{cond},
2241 delete $data->[$index]->{$rel};
2242 $data->[$index] = {%{$data->[$index]}, %$related};
2244 push @columns, keys %$related if $index == 0;
2248 ## inherit the data locked in the conditions of the resultset
2249 my ($rs_data) = $self->_merge_with_rscond({});
2250 delete @{$rs_data}{@columns};
2252 ## do bulk insert on current row
2253 $rsrc->storage->insert_bulk(
2255 [@columns, keys %$rs_data],
2256 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2259 ## do the has_many relationships
2260 foreach my $item (@$data) {
2264 foreach my $rel (@rels) {
2265 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2267 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2269 my $child = $main_row->$rel;
2271 my $related = $child->result_source->_resolve_condition(
2272 $rels->{$rel}{cond},
2278 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2279 my @populate = map { {%$_, %$related} } @rows_to_add;
2281 $child->populate( \@populate );
2288 # populate() argumnets went over several incarnations
2289 # What we ultimately support is AoH
2290 sub _normalize_populate_args {
2291 my ($self, $arg) = @_;
2293 if (ref $arg eq 'ARRAY') {
2297 elsif (ref $arg->[0] eq 'HASH') {
2300 elsif (ref $arg->[0] eq 'ARRAY') {
2302 my @colnames = @{$arg->[0]};
2303 foreach my $values (@{$arg}[1 .. $#$arg]) {
2304 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2310 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2317 =item Arguments: none
2319 =item Return Value: L<$pager|Data::Page>
2323 Returns a L<Data::Page> object for the current resultset. Only makes
2324 sense for queries with a C<page> attribute.
2326 To get the full count of entries for a paged resultset, call
2327 C<total_entries> on the L<Data::Page> object.
2334 return $self->{pager} if $self->{pager};
2336 my $attrs = $self->{attrs};
2337 if (!defined $attrs->{page}) {
2338 $self->throw_exception("Can't create pager for non-paged rs");
2340 elsif ($attrs->{page} <= 0) {
2341 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2343 $attrs->{rows} ||= 10;
2345 # throw away the paging flags and re-run the count (possibly
2346 # with a subselect) to get the real total count
2347 my $count_attrs = { %$attrs };
2348 delete @{$count_attrs}{qw/rows offset page pager/};
2350 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2352 require DBIx::Class::ResultSet::Pager;
2353 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2354 sub { $total_rs->count }, #lazy-get the total
2356 $self->{attrs}{page},
2364 =item Arguments: $page_number
2366 =item Return Value: L<$resultset|/search>
2370 Returns a resultset for the $page_number page of the resultset on which page
2371 is called, where each page contains a number of rows equal to the 'rows'
2372 attribute set on the resultset (10 by default).
2377 my ($self, $page) = @_;
2378 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2385 =item Arguments: \%col_data
2387 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2391 Creates a new result object in the resultset's result class and returns
2392 it. The row is not inserted into the database at this point, call
2393 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2394 will tell you whether the result object has been inserted or not.
2396 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2401 my ($self, $values) = @_;
2403 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2406 $self->throw_exception( "new_result expects a hashref" )
2407 unless (ref $values eq 'HASH');
2409 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2411 my $new = $self->result_class->new({
2413 ( @$cols_from_relations
2414 ? (-cols_from_relations => $cols_from_relations)
2417 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2421 reftype($new) eq 'HASH'
2427 carp_unique (sprintf (
2428 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2429 $self->result_class,
2436 # _merge_with_rscond
2438 # Takes a simple hash of K/V data and returns its copy merged with the
2439 # condition already present on the resultset. Additionally returns an
2440 # arrayref of value/condition names, which were inferred from related
2441 # objects (this is needed for in-memory related objects)
2442 sub _merge_with_rscond {
2443 my ($self, $data) = @_;
2445 my (%new_data, @cols_from_relations);
2447 my $alias = $self->{attrs}{alias};
2449 if (! defined $self->{cond}) {
2450 # just massage $data below
2452 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2453 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2454 @cols_from_relations = keys %new_data;
2456 elsif (ref $self->{cond} ne 'HASH') {
2457 $self->throw_exception(
2458 "Can't abstract implicit construct, resultset condition not a hash"
2462 # precendence must be given to passed values over values inherited from
2463 # the cond, so the order here is important.
2464 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2465 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2467 while ( my($col, $value) = each %implied ) {
2468 my $vref = ref $value;
2474 (keys %$value)[0] eq '='
2476 $new_data{$col} = $value->{'='};
2478 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2479 $new_data{$col} = $value;
2486 %{ $self->_remove_alias($data, $alias) },
2489 return (\%new_data, \@cols_from_relations);
2492 # _has_resolved_attr
2494 # determines if the resultset defines at least one
2495 # of the attributes supplied
2497 # used to determine if a subquery is neccessary
2499 # supports some virtual attributes:
2501 # This will scan for any joins being present on the resultset.
2502 # It is not a mere key-search but a deep inspection of {from}
2505 sub _has_resolved_attr {
2506 my ($self, @attr_names) = @_;
2508 my $attrs = $self->_resolved_attrs;
2512 for my $n (@attr_names) {
2513 if (grep { $n eq $_ } (qw/-join/) ) {
2514 $extra_checks{$n}++;
2518 my $attr = $attrs->{$n};
2520 next if not defined $attr;
2522 if (ref $attr eq 'HASH') {
2523 return 1 if keys %$attr;
2525 elsif (ref $attr eq 'ARRAY') {
2533 # a resolved join is expressed as a multi-level from
2535 $extra_checks{-join}
2537 ref $attrs->{from} eq 'ARRAY'
2539 @{$attrs->{from}} > 1
2547 # Recursively collapse the condition.
2549 sub _collapse_cond {
2550 my ($self, $cond, $collapsed) = @_;
2554 if (ref $cond eq 'ARRAY') {
2555 foreach my $subcond (@$cond) {
2556 next unless ref $subcond; # -or
2557 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2560 elsif (ref $cond eq 'HASH') {
2561 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2562 foreach my $subcond (@{$cond->{-and}}) {
2563 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2567 foreach my $col (keys %$cond) {
2568 my $value = $cond->{$col};
2569 $collapsed->{$col} = $value;
2579 # Remove the specified alias from the specified query hash. A copy is made so
2580 # the original query is not modified.
2583 my ($self, $query, $alias) = @_;
2585 my %orig = %{ $query || {} };
2588 foreach my $key (keys %orig) {
2590 $unaliased{$key} = $orig{$key};
2593 $unaliased{$1} = $orig{$key}
2594 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2604 =item Arguments: none
2606 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2610 Returns the SQL query and bind vars associated with the invocant.
2612 This is generally used as the RHS for a subquery.
2619 my $attrs = { %{ $self->_resolved_attrs } };
2621 my $aq = $self->result_source->storage->_select_args_to_query (
2622 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2625 $self->{_attrs}{_sqlmaker_select_args} = $attrs->{_sqlmaker_select_args};
2634 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2636 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2640 my $artist = $schema->resultset('Artist')->find_or_new(
2641 { artist => 'fred' }, { key => 'artists' });
2643 $cd->cd_to_producer->find_or_new({ producer => $producer },
2644 { key => 'primary });
2646 Find an existing record from this resultset using L</find>. if none exists,
2647 instantiate a new result object and return it. The object will not be saved
2648 into your storage until you call L<DBIx::Class::Row/insert> on it.
2650 You most likely want this method when looking for existing rows using a unique
2651 constraint that is not the primary key, or looking for related rows.
2653 If you want objects to be saved immediately, use L</find_or_create> instead.
2655 B<Note>: Make sure to read the documentation of L</find> and understand the
2656 significance of the C<key> attribute, as its lack may skew your search, and
2657 subsequently result in spurious new objects.
2659 B<Note>: Take care when using C<find_or_new> with a table having
2660 columns with default values that you intend to be automatically
2661 supplied by the database (e.g. an auto_increment primary key column).
2662 In normal usage, the value of such columns should NOT be included at
2663 all in the call to C<find_or_new>, even when set to C<undef>.
2669 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2670 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2671 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2674 return $self->new_result($hash);
2681 =item Arguments: \%col_data
2683 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2687 Attempt to create a single new row or a row with multiple related rows
2688 in the table represented by the resultset (and related tables). This
2689 will not check for duplicate rows before inserting, use
2690 L</find_or_create> to do that.
2692 To create one row for this resultset, pass a hashref of key/value
2693 pairs representing the columns of the table and the values you wish to
2694 store. If the appropriate relationships are set up, foreign key fields
2695 can also be passed an object representing the foreign row, and the
2696 value will be set to its primary key.
2698 To create related objects, pass a hashref of related-object column values
2699 B<keyed on the relationship name>. If the relationship is of type C<multi>
2700 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2701 The process will correctly identify columns holding foreign keys, and will
2702 transparently populate them from the keys of the corresponding relation.
2703 This can be applied recursively, and will work correctly for a structure
2704 with an arbitrary depth and width, as long as the relationships actually
2705 exists and the correct column data has been supplied.
2707 Instead of hashrefs of plain related data (key/value pairs), you may
2708 also pass new or inserted objects. New objects (not inserted yet, see
2709 L</new_result>), will be inserted into their appropriate tables.
2711 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2713 Example of creating a new row.
2715 $person_rs->create({
2716 name=>"Some Person",
2717 email=>"somebody@someplace.com"
2720 Example of creating a new row and also creating rows in a related C<has_many>
2721 or C<has_one> resultset. Note Arrayref.
2724 { artistid => 4, name => 'Manufactured Crap', cds => [
2725 { title => 'My First CD', year => 2006 },
2726 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2731 Example of creating a new row and also creating a row in a related
2732 C<belongs_to> resultset. Note Hashref.
2735 title=>"Music for Silly Walks",
2738 name=>"Silly Musician",
2746 When subclassing ResultSet never attempt to override this method. Since
2747 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2748 lot of the internals simply never call it, so your override will be
2749 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2750 or L<DBIx::Class::Row/insert> depending on how early in the
2751 L</create> process you need to intervene. See also warning pertaining to
2759 my ($self, $col_data) = @_;
2760 $self->throw_exception( "create needs a hashref" )
2761 unless ref $col_data eq 'HASH';
2762 return $self->new_result($col_data)->insert;
2765 =head2 find_or_create
2769 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2771 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2775 $cd->cd_to_producer->find_or_create({ producer => $producer },
2776 { key => 'primary' });
2778 Tries to find a record based on its primary key or unique constraints; if none
2779 is found, creates one and returns that instead.
2781 my $cd = $schema->resultset('CD')->find_or_create({
2783 artist => 'Massive Attack',
2784 title => 'Mezzanine',
2788 Also takes an optional C<key> attribute, to search by a specific key or unique
2789 constraint. For example:
2791 my $cd = $schema->resultset('CD')->find_or_create(
2793 artist => 'Massive Attack',
2794 title => 'Mezzanine',
2796 { key => 'cd_artist_title' }
2799 B<Note>: Make sure to read the documentation of L</find> and understand the
2800 significance of the C<key> attribute, as its lack may skew your search, and
2801 subsequently result in spurious row creation.
2803 B<Note>: Because find_or_create() reads from the database and then
2804 possibly inserts based on the result, this method is subject to a race
2805 condition. Another process could create a record in the table after
2806 the find has completed and before the create has started. To avoid
2807 this problem, use find_or_create() inside a transaction.
2809 B<Note>: Take care when using C<find_or_create> with a table having
2810 columns with default values that you intend to be automatically
2811 supplied by the database (e.g. an auto_increment primary key column).
2812 In normal usage, the value of such columns should NOT be included at
2813 all in the call to C<find_or_create>, even when set to C<undef>.
2815 See also L</find> and L</update_or_create>. For information on how to declare
2816 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2818 If you need to know if an existing row was found or a new one created use
2819 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2820 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2823 my $cd = $schema->resultset('CD')->find_or_new({
2825 artist => 'Massive Attack',
2826 title => 'Mezzanine',
2830 if( !$cd->in_storage ) {
2837 sub find_or_create {
2839 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2840 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2841 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2844 return $self->create($hash);
2847 =head2 update_or_create
2851 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2853 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2857 $resultset->update_or_create({ col => $val, ... });
2859 Like L</find_or_create>, but if a row is found it is immediately updated via
2860 C<< $found_row->update (\%col_data) >>.
2863 Takes an optional C<key> attribute to search on a specific unique constraint.
2866 # In your application
2867 my $cd = $schema->resultset('CD')->update_or_create(
2869 artist => 'Massive Attack',
2870 title => 'Mezzanine',
2873 { key => 'cd_artist_title' }
2876 $cd->cd_to_producer->update_or_create({
2877 producer => $producer,
2883 B<Note>: Make sure to read the documentation of L</find> and understand the
2884 significance of the C<key> attribute, as its lack may skew your search, and
2885 subsequently result in spurious row creation.
2887 B<Note>: Take care when using C<update_or_create> with a table having
2888 columns with default values that you intend to be automatically
2889 supplied by the database (e.g. an auto_increment primary key column).
2890 In normal usage, the value of such columns should NOT be included at
2891 all in the call to C<update_or_create>, even when set to C<undef>.
2893 See also L</find> and L</find_or_create>. For information on how to declare
2894 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2896 If you need to know if an existing row was updated or a new one created use
2897 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2898 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2903 sub update_or_create {
2905 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2906 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2908 my $row = $self->find($cond, $attrs);
2910 $row->update($cond);
2914 return $self->create($cond);
2917 =head2 update_or_new
2921 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2923 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2927 $resultset->update_or_new({ col => $val, ... });
2929 Like L</find_or_new> but if a row is found it is immediately updated via
2930 C<< $found_row->update (\%col_data) >>.
2934 # In your application
2935 my $cd = $schema->resultset('CD')->update_or_new(
2937 artist => 'Massive Attack',
2938 title => 'Mezzanine',
2941 { key => 'cd_artist_title' }
2944 if ($cd->in_storage) {
2945 # the cd was updated
2948 # the cd is not yet in the database, let's insert it
2952 B<Note>: Make sure to read the documentation of L</find> and understand the
2953 significance of the C<key> attribute, as its lack may skew your search, and
2954 subsequently result in spurious new objects.
2956 B<Note>: Take care when using C<update_or_new> with a table having
2957 columns with default values that you intend to be automatically
2958 supplied by the database (e.g. an auto_increment primary key column).
2959 In normal usage, the value of such columns should NOT be included at
2960 all in the call to C<update_or_new>, even when set to C<undef>.
2962 See also L</find>, L</find_or_create> and L</find_or_new>.
2968 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2969 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2971 my $row = $self->find( $cond, $attrs );
2972 if ( defined $row ) {
2973 $row->update($cond);
2977 return $self->new_result($cond);
2984 =item Arguments: none
2986 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2990 Gets the contents of the cache for the resultset, if the cache is set.
2992 The cache is populated either by using the L</prefetch> attribute to
2993 L</search> or by calling L</set_cache>.
3005 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3007 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3011 Sets the contents of the cache for the resultset. Expects an arrayref
3012 of objects of the same class as those produced by the resultset. Note that
3013 if the cache is set, the resultset will return the cached objects rather
3014 than re-querying the database even if the cache attr is not set.
3016 The contents of the cache can also be populated by using the
3017 L</prefetch> attribute to L</search>.
3022 my ( $self, $data ) = @_;
3023 $self->throw_exception("set_cache requires an arrayref")
3024 if defined($data) && (ref $data ne 'ARRAY');
3025 $self->{all_cache} = $data;
3032 =item Arguments: none
3034 =item Return Value: undef
3038 Clears the cache for the resultset.
3043 shift->set_cache(undef);
3050 =item Arguments: none
3052 =item Return Value: true, if the resultset has been paginated
3060 return !!$self->{attrs}{page};
3067 =item Arguments: none
3069 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3077 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3080 =head2 related_resultset
3084 =item Arguments: $rel_name
3086 =item Return Value: L<$resultset|/search>
3090 Returns a related resultset for the supplied relationship name.
3092 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3096 sub related_resultset {
3097 my ($self, $rel) = @_;
3099 return $self->{related_resultsets}{$rel}
3100 if defined $self->{related_resultsets}{$rel};
3102 return $self->{related_resultsets}{$rel} = do {
3103 my $rsrc = $self->result_source;
3104 my $rel_info = $rsrc->relationship_info($rel);
3106 $self->throw_exception(
3107 "search_related: result source '" . $rsrc->source_name .
3108 "' has no such relationship $rel")
3111 my $attrs = $self->_chain_relationship($rel);
3113 my $join_count = $attrs->{seen_join}{$rel};
3115 my $alias = $self->result_source->storage
3116 ->relname_to_table_alias($rel, $join_count);
3118 # since this is search_related, and we already slid the select window inwards
3119 # (the select/as attrs were deleted in the beginning), we need to flip all
3120 # left joins to inner, so we get the expected results
3121 # read the comment on top of the actual function to see what this does
3122 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3125 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3126 delete @{$attrs}{qw(result_class alias)};
3130 if (my $cache = $self->get_cache) {
3131 $related_cache = [ map
3132 { @{$_->related_resultset($rel)->get_cache||[]} }
3137 my $rel_source = $rsrc->related_source($rel);
3141 # The reason we do this now instead of passing the alias to the
3142 # search_rs below is that if you wrap/overload resultset on the
3143 # source you need to know what alias it's -going- to have for things
3144 # to work sanely (e.g. RestrictWithObject wants to be able to add
3145 # extra query restrictions, and these may need to be $alias.)
3147 my $rel_attrs = $rel_source->resultset_attributes;
3148 local $rel_attrs->{alias} = $alias;
3150 $rel_source->resultset
3154 where => $attrs->{where},
3157 $new->set_cache($related_cache) if $related_cache;
3162 =head2 current_source_alias
3166 =item Arguments: none
3168 =item Return Value: $source_alias
3172 Returns the current table alias for the result source this resultset is built
3173 on, that will be used in the SQL query. Usually it is C<me>.
3175 Currently the source alias that refers to the result set returned by a
3176 L</search>/L</find> family method depends on how you got to the resultset: it's
3177 C<me> by default, but eg. L</search_related> aliases it to the related result
3178 source name (and keeps C<me> referring to the original result set). The long
3179 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3180 (and make this method unnecessary).
3182 Thus it's currently necessary to use this method in predefined queries (see
3183 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3184 source alias of the current result set:
3186 # in a result set class
3188 my ($self, $user) = @_;
3190 my $me = $self->current_source_alias;
3192 return $self->search({
3193 "$me.modified" => $user->id,
3199 sub current_source_alias {
3200 return (shift->{attrs} || {})->{alias} || 'me';
3203 =head2 as_subselect_rs
3207 =item Arguments: none
3209 =item Return Value: L<$resultset|/search>
3213 Act as a barrier to SQL symbols. The resultset provided will be made into a
3214 "virtual view" by including it as a subquery within the from clause. From this
3215 point on, any joined tables are inaccessible to ->search on the resultset (as if
3216 it were simply where-filtered without joins). For example:
3218 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3220 # 'x' now pollutes the query namespace
3222 # So the following works as expected
3223 my $ok_rs = $rs->search({'x.other' => 1});
3225 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3226 # def) we look for one row with contradictory terms and join in another table
3227 # (aliased 'x_2') which we never use
3228 my $broken_rs = $rs->search({'x.name' => 'def'});
3230 my $rs2 = $rs->as_subselect_rs;
3232 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3233 my $not_joined_rs = $rs2->search({'x.other' => 1});
3235 # works as expected: finds a 'table' row related to two x rows (abc and def)
3236 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3238 Another example of when one might use this would be to select a subset of
3239 columns in a group by clause:
3241 my $rs = $schema->resultset('Bar')->search(undef, {
3242 group_by => [qw{ id foo_id baz_id }],
3243 })->as_subselect_rs->search(undef, {
3244 columns => [qw{ id foo_id }]
3247 In the above example normally columns would have to be equal to the group by,
3248 but because we isolated the group by into a subselect the above works.
3252 sub as_subselect_rs {
3255 my $attrs = $self->_resolved_attrs;
3257 my $fresh_rs = (ref $self)->new (
3258 $self->result_source
3261 # these pieces will be locked in the subquery
3262 delete $fresh_rs->{cond};
3263 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3265 return $fresh_rs->search( {}, {
3267 $attrs->{alias} => $self->as_query,
3268 -alias => $attrs->{alias},
3269 -rsrc => $self->result_source,
3271 alias => $attrs->{alias},
3275 # This code is called by search_related, and makes sure there
3276 # is clear separation between the joins before, during, and
3277 # after the relationship. This information is needed later
3278 # in order to properly resolve prefetch aliases (any alias
3279 # with a relation_chain_depth less than the depth of the
3280 # current prefetch is not considered)
3282 # The increments happen twice per join. An even number means a
3283 # relationship specified via a search_related, whereas an odd
3284 # number indicates a join/prefetch added via attributes
3286 # Also this code will wrap the current resultset (the one we
3287 # chain to) in a subselect IFF it contains limiting attributes
3288 sub _chain_relationship {
3289 my ($self, $rel) = @_;
3290 my $source = $self->result_source;
3291 my $attrs = { %{$self->{attrs}||{}} };
3293 # we need to take the prefetch the attrs into account before we
3294 # ->_resolve_join as otherwise they get lost - captainL
3295 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3297 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3299 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3302 my @force_subq_attrs = qw/offset rows group_by having/;
3305 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3307 $self->_has_resolved_attr (@force_subq_attrs)
3309 # Nuke the prefetch (if any) before the new $rs attrs
3310 # are resolved (prefetch is useless - we are wrapping
3311 # a subquery anyway).
3312 my $rs_copy = $self->search;
3313 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3314 $rs_copy->{attrs}{join},
3315 delete $rs_copy->{attrs}{prefetch},
3320 -alias => $attrs->{alias},
3321 $attrs->{alias} => $rs_copy->as_query,
3323 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3324 $seen->{-relation_chain_depth} = 0;
3326 elsif ($attrs->{from}) { #shallow copy suffices
3327 $from = [ @{$attrs->{from}} ];
3332 -alias => $attrs->{alias},
3333 $attrs->{alias} => $source->from,
3337 my $jpath = ($seen->{-relation_chain_depth})
3338 ? $from->[-1][0]{-join_path}
3341 my @requested_joins = $source->_resolve_join(
3348 push @$from, @requested_joins;
3350 $seen->{-relation_chain_depth}++;
3352 # if $self already had a join/prefetch specified on it, the requested
3353 # $rel might very well be already included. What we do in this case
3354 # is effectively a no-op (except that we bump up the chain_depth on
3355 # the join in question so we could tell it *is* the search_related)
3358 # we consider the last one thus reverse
3359 for my $j (reverse @requested_joins) {
3360 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3361 if ($rel eq $last_j) {
3362 $j->[0]{-relation_chain_depth}++;
3368 unless ($already_joined) {
3369 push @$from, $source->_resolve_join(
3377 $seen->{-relation_chain_depth}++;
3379 return {%$attrs, from => $from, seen_join => $seen};
3382 sub _resolved_attrs {
3384 return $self->{_attrs} if $self->{_attrs};
3386 my $attrs = { %{ $self->{attrs} || {} } };
3387 my $source = $self->result_source;
3388 my $alias = $attrs->{alias};
3390 # default selection list
3391 $attrs->{columns} = [ $source->columns ]
3392 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3394 # merge selectors together
3395 for (qw/columns select as/) {
3396 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3397 if $attrs->{$_} or $attrs->{"+$_"};
3400 # disassemble columns
3402 if (my $cols = delete $attrs->{columns}) {
3403 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3404 if (ref $c eq 'HASH') {
3405 for my $as (sort keys %$c) {
3406 push @sel, $c->{$as};
3417 # when trying to weed off duplicates later do not go past this point -
3418 # everything added from here on is unbalanced "anyone's guess" stuff
3419 my $dedup_stop_idx = $#as;
3421 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3423 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3424 if $attrs->{select};
3426 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3427 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3429 # disqualify all $alias.col as-bits (inflate-map mandated)
3430 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3432 # de-duplicate the result (remove *identical* select/as pairs)
3433 # and also die on duplicate {as} pointing to different {select}s
3434 # not using a c-style for as the condition is prone to shrinkage
3437 while ($i <= $dedup_stop_idx) {
3438 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3443 elsif ($seen->{$as[$i]}++) {
3444 $self->throw_exception(
3445 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3453 $attrs->{select} = \@sel;
3454 $attrs->{as} = \@as;
3456 $attrs->{from} ||= [{
3458 -alias => $self->{attrs}{alias},
3459 $self->{attrs}{alias} => $source->from,
3462 if ( $attrs->{join} || $attrs->{prefetch} ) {
3464 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3465 if ref $attrs->{from} ne 'ARRAY';
3467 my $join = (delete $attrs->{join}) || {};
3469 if ( defined $attrs->{prefetch} ) {
3470 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3473 $attrs->{from} = # have to copy here to avoid corrupting the original
3475 @{ $attrs->{from} },
3476 $source->_resolve_join(
3479 { %{ $attrs->{seen_join} || {} } },
3480 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3481 ? $attrs->{from}[-1][0]{-join_path}
3488 if ( defined $attrs->{order_by} ) {
3489 $attrs->{order_by} = (
3490 ref( $attrs->{order_by} ) eq 'ARRAY'
3491 ? [ @{ $attrs->{order_by} } ]
3492 : [ $attrs->{order_by} || () ]
3496 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3497 $attrs->{group_by} = [ $attrs->{group_by} ];
3500 # generate the distinct induced group_by early, as prefetch will be carried via a
3501 # subquery (since a group_by is present)
3502 if (delete $attrs->{distinct}) {
3503 if ($attrs->{group_by}) {
3504 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3507 $attrs->{_grouped_by_distinct} = 1;
3508 # distinct affects only the main selection part, not what prefetch may
3510 $attrs->{group_by} = $source->storage->_group_over_selection($attrs);
3514 # generate selections based on the prefetch helper
3516 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3517 if defined $attrs->{prefetch};
3521 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3522 if $attrs->{_dark_selector};
3524 $attrs->{collapse} = 1;
3526 # this is a separate structure (we don't look in {from} directly)
3527 # as the resolver needs to shift things off the lists to work
3528 # properly (identical-prefetches on different branches)
3530 if (ref $attrs->{from} eq 'ARRAY') {
3532 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3534 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3535 next unless $j->[0]{-alias};
3536 next unless $j->[0]{-join_path};
3537 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3539 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3542 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3543 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3547 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3549 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3550 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3553 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3554 $attrs->{_related_results_construction} = 1;
3557 # run through the resulting joinstructure (starting from our current slot)
3558 # and unset collapse if proven unnesessary
3560 # also while we are at it find out if the current root source has
3561 # been premultiplied by previous related_source chaining
3563 # this allows to predict whether a root object with all other relation
3564 # data set to NULL is in fact unique
3565 if ($attrs->{collapse}) {
3567 if (ref $attrs->{from} eq 'ARRAY') {
3569 if (@{$attrs->{from}} == 1) {
3570 # no joins - no collapse
3571 $attrs->{collapse} = 0;
3574 # find where our table-spec starts
3575 my @fromlist = @{$attrs->{from}};
3577 my $t = shift @fromlist;
3580 # me vs join from-spec distinction - a ref means non-root
3581 if (ref $t eq 'ARRAY') {
3583 $is_multi ||= ! $t->{-is_single};
3585 last if ($t->{-alias} && $t->{-alias} eq $alias);
3586 $attrs->{_main_source_premultiplied} ||= $is_multi;
3589 # no non-singles remaining, nor any premultiplication - nothing to collapse
3591 ! $attrs->{_main_source_premultiplied}
3593 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3595 $attrs->{collapse} = 0;
3601 # if we can not analyze the from - err on the side of safety
3602 $attrs->{_main_source_premultiplied} = 1;
3606 # if both page and offset are specified, produce a combined offset
3607 # even though it doesn't make much sense, this is what pre 081xx has
3609 if (my $page = delete $attrs->{page}) {
3611 ($attrs->{rows} * ($page - 1))
3613 ($attrs->{offset} || 0)
3617 return $self->{_attrs} = $attrs;
3621 my ($self, $attr) = @_;
3623 if (ref $attr eq 'HASH') {
3624 return $self->_rollout_hash($attr);
3625 } elsif (ref $attr eq 'ARRAY') {
3626 return $self->_rollout_array($attr);
3632 sub _rollout_array {
3633 my ($self, $attr) = @_;
3636 foreach my $element (@{$attr}) {
3637 if (ref $element eq 'HASH') {
3638 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3639 } elsif (ref $element eq 'ARRAY') {
3640 # XXX - should probably recurse here
3641 push( @rolled_array, @{$self->_rollout_array($element)} );
3643 push( @rolled_array, $element );
3646 return \@rolled_array;
3650 my ($self, $attr) = @_;
3653 foreach my $key (keys %{$attr}) {
3654 push( @rolled_array, { $key => $attr->{$key} } );
3656 return \@rolled_array;
3659 sub _calculate_score {
3660 my ($self, $a, $b) = @_;
3662 if (defined $a xor defined $b) {
3665 elsif (not defined $a) {
3669 if (ref $b eq 'HASH') {
3670 my ($b_key) = keys %{$b};
3671 if (ref $a eq 'HASH') {
3672 my ($a_key) = keys %{$a};
3673 if ($a_key eq $b_key) {
3674 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3679 return ($a eq $b_key) ? 1 : 0;
3682 if (ref $a eq 'HASH') {
3683 my ($a_key) = keys %{$a};
3684 return ($b eq $a_key) ? 1 : 0;
3686 return ($b eq $a) ? 1 : 0;
3691 sub _merge_joinpref_attr {
3692 my ($self, $orig, $import) = @_;
3694 return $import unless defined($orig);
3695 return $orig unless defined($import);
3697 $orig = $self->_rollout_attr($orig);
3698 $import = $self->_rollout_attr($import);
3701 foreach my $import_element ( @{$import} ) {
3702 # find best candidate from $orig to merge $b_element into
3703 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3704 foreach my $orig_element ( @{$orig} ) {
3705 my $score = $self->_calculate_score( $orig_element, $import_element );
3706 if ($score > $best_candidate->{score}) {
3707 $best_candidate->{position} = $position;
3708 $best_candidate->{score} = $score;
3712 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3713 $import_key = '' if not defined $import_key;
3715 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3716 push( @{$orig}, $import_element );
3718 my $orig_best = $orig->[$best_candidate->{position}];
3719 # merge orig_best and b_element together and replace original with merged
3720 if (ref $orig_best ne 'HASH') {
3721 $orig->[$best_candidate->{position}] = $import_element;
3722 } elsif (ref $import_element eq 'HASH') {
3723 my ($key) = keys %{$orig_best};
3724 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3727 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3730 return @$orig ? $orig : ();
3738 require Hash::Merge;
3739 my $hm = Hash::Merge->new;
3741 $hm->specify_behavior({
3744 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3746 if ($defl xor $defr) {
3747 return [ $defl ? $_[0] : $_[1] ];
3752 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3756 return [$_[0], $_[1]];
3760 return $_[1] if !defined $_[0];
3761 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3762 return [$_[0], @{$_[1]}]
3765 return [] if !defined $_[0] and !keys %{$_[1]};
3766 return [ $_[1] ] if !defined $_[0];
3767 return [ $_[0] ] if !keys %{$_[1]};
3768 return [$_[0], $_[1]]
3773 return $_[0] if !defined $_[1];
3774 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3775 return [@{$_[0]}, $_[1]]
3778 my @ret = @{$_[0]} or return $_[1];
3779 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3780 my %idx = map { $_ => 1 } @ret;
3781 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3785 return [ $_[1] ] if ! @{$_[0]};
3786 return $_[0] if !keys %{$_[1]};
3787 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3788 return [ @{$_[0]}, $_[1] ];
3793 return [] if !keys %{$_[0]} and !defined $_[1];
3794 return [ $_[0] ] if !defined $_[1];
3795 return [ $_[1] ] if !keys %{$_[0]};
3796 return [$_[0], $_[1]]
3799 return [] if !keys %{$_[0]} and !@{$_[1]};
3800 return [ $_[0] ] if !@{$_[1]};
3801 return $_[1] if !keys %{$_[0]};
3802 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3803 return [ $_[0], @{$_[1]} ];
3806 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3807 return [ $_[0] ] if !keys %{$_[1]};
3808 return [ $_[1] ] if !keys %{$_[0]};
3809 return [ $_[0] ] if $_[0] eq $_[1];
3810 return [ $_[0], $_[1] ];
3813 } => 'DBIC_RS_ATTR_MERGER');
3817 return $hm->merge ($_[1], $_[2]);
3821 sub STORABLE_freeze {
3822 my ($self, $cloning) = @_;
3823 my $to_serialize = { %$self };
3825 # A cursor in progress can't be serialized (and would make little sense anyway)
3826 # the parser can be regenerated (and can't be serialized)
3827 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3829 # nor is it sensical to store a not-yet-fired-count pager
3830 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3831 delete $to_serialize->{pager};
3834 Storable::nfreeze($to_serialize);
3837 # need this hook for symmetry
3839 my ($self, $cloning, $serialized) = @_;
3841 %$self = %{ Storable::thaw($serialized) };
3847 =head2 throw_exception
3849 See L<DBIx::Class::Schema/throw_exception> for details.
3853 sub throw_exception {
3856 if (ref $self and my $rsrc = $self->result_source) {
3857 $rsrc->throw_exception(@_)
3860 DBIx::Class::Exception->throw(@_);
3868 # XXX: FIXME: Attributes docs need clearing up
3872 Attributes are used to refine a ResultSet in various ways when
3873 searching for data. They can be passed to any method which takes an
3874 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3877 Default attributes can be set on the result class using
3878 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3879 the CAVEATS on that feature before using it!)
3881 These are in no particular order:
3887 =item Value: ( $order_by | \@order_by | \%order_by )
3891 Which column(s) to order the results by.
3893 [The full list of suitable values is documented in
3894 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3897 If a single column name, or an arrayref of names is supplied, the
3898 argument is passed through directly to SQL. The hashref syntax allows
3899 for connection-agnostic specification of ordering direction:
3901 For descending order:
3903 order_by => { -desc => [qw/col1 col2 col3/] }
3905 For explicit ascending order:
3907 order_by => { -asc => 'col' }
3909 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3910 supported, although you are strongly encouraged to use the hashref
3911 syntax as outlined above.
3917 =item Value: \@columns | \%columns | $column
3921 Shortcut to request a particular set of columns to be retrieved. Each
3922 column spec may be a string (a table column name), or a hash (in which
3923 case the key is the C<as> value, and the value is used as the C<select>
3924 expression). Adds C<me.> onto the start of any column without a C<.> in
3925 it and sets C<select> from that, then auto-populates C<as> from
3926 C<select> as normal. (You may also use the C<cols> attribute, as in
3927 earlier versions of DBIC, but this is deprecated.)
3929 Essentially C<columns> does the same as L</select> and L</as>.
3931 columns => [ 'foo', { bar => 'baz' } ]
3935 select => [qw/foo baz/],
3942 =item Value: \@columns
3946 Indicates additional columns to be selected from storage. Works the same as
3947 L</columns> but adds columns to the selection. (You may also use the
3948 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3949 deprecated). For example:-
3951 $schema->resultset('CD')->search(undef, {
3952 '+columns' => ['artist.name'],
3956 would return all CDs and include a 'name' column to the information
3957 passed to object inflation. Note that the 'artist' is the name of the
3958 column (or relationship) accessor, and 'name' is the name of the column
3959 accessor in the related table.
3961 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3962 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3963 unary plus operator before it.
3965 =head2 include_columns
3969 =item Value: \@columns
3973 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3979 =item Value: \@select_columns
3983 Indicates which columns should be selected from the storage. You can use
3984 column names, or in the case of RDBMS back ends, function or stored procedure
3987 $rs = $schema->resultset('Employee')->search(undef, {
3990 { count => 'employeeid' },
3991 { max => { length => 'name' }, -as => 'longest_name' }
3996 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3998 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3999 use L</select>, to instruct DBIx::Class how to store the result of the column.
4000 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
4001 identifier aliasing. You can however alias a function, so you can use it in
4002 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
4003 attribute> supplied as shown in the example above.
4005 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
4006 Not doing so causes Perl to incorrectly interpret them as a bareword with a
4007 unary plus operator before it.
4013 Indicates additional columns to be selected from storage. Works the same as
4014 L</select> but adds columns to the default selection, instead of specifying
4023 =item Value: \@inflation_names
4027 Indicates column names for object inflation. That is L</as> indicates the
4028 slot name in which the column value will be stored within the
4029 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4030 identifier by the C<get_column> method (or via the object accessor B<if one
4031 with the same name already exists>) as shown below. The L</as> attribute has
4032 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4034 $rs = $schema->resultset('Employee')->search(undef, {
4037 { count => 'employeeid' },
4038 { max => { length => 'name' }, -as => 'longest_name' }
4047 If the object against which the search is performed already has an accessor
4048 matching a column name specified in C<as>, the value can be retrieved using
4049 the accessor as normal:
4051 my $name = $employee->name();
4053 If on the other hand an accessor does not exist in the object, you need to
4054 use C<get_column> instead:
4056 my $employee_count = $employee->get_column('employee_count');
4058 You can create your own accessors if required - see
4059 L<DBIx::Class::Manual::Cookbook> for details.
4065 Indicates additional column names for those added via L</+select>. See L</as>.
4073 =item Value: ($rel_name | \@rel_names | \%rel_names)
4077 Contains a list of relationships that should be joined for this query. For
4080 # Get CDs by Nine Inch Nails
4081 my $rs = $schema->resultset('CD')->search(
4082 { 'artist.name' => 'Nine Inch Nails' },
4083 { join => 'artist' }
4086 Can also contain a hash reference to refer to the other relation's relations.
4089 package MyApp::Schema::Track;
4090 use base qw/DBIx::Class/;
4091 __PACKAGE__->table('track');
4092 __PACKAGE__->add_columns(qw/trackid cd position title/);
4093 __PACKAGE__->set_primary_key('trackid');
4094 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4097 # In your application
4098 my $rs = $schema->resultset('Artist')->search(
4099 { 'track.title' => 'Teardrop' },
4101 join => { cd => 'track' },
4102 order_by => 'artist.name',
4106 You need to use the relationship (not the table) name in conditions,
4107 because they are aliased as such. The current table is aliased as "me", so
4108 you need to use me.column_name in order to avoid ambiguity. For example:
4110 # Get CDs from 1984 with a 'Foo' track
4111 my $rs = $schema->resultset('CD')->search(
4114 'tracks.name' => 'Foo'
4116 { join => 'tracks' }
4119 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4120 similarly for a third time). For e.g.
4122 my $rs = $schema->resultset('Artist')->search({
4123 'cds.title' => 'Down to Earth',
4124 'cds_2.title' => 'Popular',
4126 join => [ qw/cds cds/ ],
4129 will return a set of all artists that have both a cd with title 'Down
4130 to Earth' and a cd with title 'Popular'.
4132 If you want to fetch related objects from other tables as well, see L</prefetch>
4135 NOTE: An internal join-chain pruner will discard certain joins while
4136 constructing the actual SQL query, as long as the joins in question do not
4137 affect the retrieved result. This for example includes 1:1 left joins
4138 that are not part of the restriction specification (WHERE/HAVING) nor are
4139 a part of the query selection.
4141 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4147 =item Value: (0 | 1)
4151 When set to a true value, indicates that any rows fetched from joined has_many
4152 relationships are to be aggregated into the corresponding "parent" object. For
4153 example, the resultset:
4155 my $rs = $schema->resultset('CD')->search({}, {
4156 '+columns' => [ qw/ tracks.title tracks.position / ],
4161 While executing the following query:
4163 SELECT me.*, tracks.title, tracks.position
4165 LEFT JOIN track tracks
4166 ON tracks.cdid = me.cdid
4168 Will return only as many objects as there are rows in the CD source, even
4169 though the result of the query may span many rows. Each of these CD objects
4170 will in turn have multiple "Track" objects hidden behind the has_many
4171 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4172 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4173 product"), with each CD object containing exactly one of all fetched Track data.
4175 When a collapse is requested on a non-ordered resultset, an order by some
4176 unique part of the main source (the left-most table) is inserted automatically.
4177 This is done so that the resultset is allowed to be "lazy" - calling
4178 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4179 object with all of its related data.
4181 If an L</order_by> is already declared, and orders the resultset in a way that
4182 makes collapsing as described above impossible (e.g. C<< ORDER BY
4183 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4184 switch to "eager" mode and slurp the entire resultset before consturcting the
4185 first object returned by L</next>.
4187 Setting this attribute on a resultset that does not join any has_many
4188 relations is a no-op.
4190 For a more in-depth discussion, see L</PREFETCHING>.
4196 =item Value: ($rel_name | \@rel_names | \%rel_names)
4200 This attribute is a shorthand for specifying a L</join> spec, adding all
4201 columns from the joined related sources as L</+columns> and setting
4202 L</collapse> to a true value. For example, the following two queries are
4205 my $rs = $schema->resultset('Artist')->search({}, {
4206 prefetch => { cds => ['genre', 'tracks' ] },
4211 my $rs = $schema->resultset('Artist')->search({}, {
4212 join => { cds => ['genre', 'tracks' ] },
4216 { +{ "cds.$_" => "cds.$_" } }
4217 $schema->source('Artist')->related_source('cds')->columns
4220 { +{ "cds.genre.$_" => "genre.$_" } }
4221 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4224 { +{ "cds.tracks.$_" => "tracks.$_" } }
4225 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4230 Both producing the following SQL:
4232 SELECT me.artistid, me.name, me.rank, me.charfield,
4233 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4234 genre.genreid, genre.name,
4235 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4238 ON cds.artist = me.artistid
4239 LEFT JOIN genre genre
4240 ON genre.genreid = cds.genreid
4241 LEFT JOIN track tracks
4242 ON tracks.cd = cds.cdid
4243 ORDER BY me.artistid
4245 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4246 the arguments are properly merged and generally do the right thing. For
4247 example, you may want to do the following:
4249 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4250 { 'genre.genreid' => undef },
4252 join => { cds => 'genre' },
4257 Which generates the following SQL:
4259 SELECT me.artistid, me.name, me.rank, me.charfield,
4260 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4263 ON cds.artist = me.artistid
4264 LEFT JOIN genre genre
4265 ON genre.genreid = cds.genreid
4266 WHERE genre.genreid IS NULL
4267 ORDER BY me.artistid
4269 For a more in-depth discussion, see L</PREFETCHING>.
4275 =item Value: $source_alias
4279 Sets the source alias for the query. Normally, this defaults to C<me>, but
4280 nested search queries (sub-SELECTs) might need specific aliases set to
4281 reference inner queries. For example:
4284 ->related_resultset('CDs')
4285 ->related_resultset('Tracks')
4287 'track.id' => { -ident => 'none_search.id' },
4291 my $ids = $self->search({
4294 alias => 'none_search',
4295 group_by => 'none_search.id',
4296 })->get_column('id')->as_query;
4298 $self->search({ id => { -in => $ids } })
4300 This attribute is directly tied to L</current_source_alias>.
4310 Makes the resultset paged and specifies the page to retrieve. Effectively
4311 identical to creating a non-pages resultset and then calling ->page($page)
4314 If L</rows> attribute is not specified it defaults to 10 rows per page.
4316 When you have a paged resultset, L</count> will only return the number
4317 of rows in the page. To get the total, use the L</pager> and call
4318 C<total_entries> on it.
4328 Specifies the maximum number of rows for direct retrieval or the number of
4329 rows per page if the page attribute or method is used.
4335 =item Value: $offset
4339 Specifies the (zero-based) row number for the first row to be returned, or the
4340 of the first row of the first page if paging is used.
4342 =head2 software_limit
4346 =item Value: (0 | 1)
4350 When combined with L</rows> and/or L</offset> the generated SQL will not
4351 include any limit dialect stanzas. Instead the entire result will be selected
4352 as if no limits were specified, and DBIC will perform the limit locally, by
4353 artificially advancing and finishing the resulting L</cursor>.
4355 This is the recommended way of performing resultset limiting when no sane RDBMS
4356 implementation is available (e.g.
4357 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4358 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4364 =item Value: \@columns
4368 A arrayref of columns to group by. Can include columns of joined tables.
4370 group_by => [qw/ column1 column2 ... /]
4376 =item Value: $condition
4380 HAVING is a select statement attribute that is applied between GROUP BY and
4381 ORDER BY. It is applied to the after the grouping calculations have been
4384 having => { 'count_employee' => { '>=', 100 } }
4386 or with an in-place function in which case literal SQL is required:
4388 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4394 =item Value: (0 | 1)
4398 Set to 1 to group by all columns. If the resultset already has a group_by
4399 attribute, this setting is ignored and an appropriate warning is issued.
4405 Adds to the WHERE clause.
4407 # only return rows WHERE deleted IS NULL for all searches
4408 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4410 Can be overridden by passing C<< { where => undef } >> as an attribute
4413 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4419 Set to 1 to cache search results. This prevents extra SQL queries if you
4420 revisit rows in your ResultSet:
4422 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4424 while( my $artist = $resultset->next ) {
4428 $rs->first; # without cache, this would issue a query
4430 By default, searches are not cached.
4432 For more examples of using these attributes, see
4433 L<DBIx::Class::Manual::Cookbook>.
4439 =item Value: ( 'update' | 'shared' | \$scalar )
4443 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4444 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4449 DBIx::Class supports arbitrary related data prefetching from multiple related
4450 sources. Any combination of relationship types and column sets are supported.
4451 If L<collapsing|/collapse> is requested, there is an additional requirement of
4452 selecting enough data to make every individual object uniquely identifiable.
4454 Here are some more involved examples, based on the following relationship map:
4457 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4458 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4459 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4461 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4463 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4467 my $rs = $schema->resultset('Tag')->search(
4476 The initial search results in SQL like the following:
4478 SELECT tag.*, cd.*, artist.* FROM tag
4479 JOIN cd ON tag.cd = cd.cdid
4480 JOIN artist ON cd.artist = artist.artistid
4482 L<DBIx::Class> has no need to go back to the database when we access the
4483 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4486 Simple prefetches will be joined automatically, so there is no need
4487 for a C<join> attribute in the above search.
4489 The L</prefetch> attribute can be used with any of the relationship types
4490 and multiple prefetches can be specified together. Below is a more complex
4491 example that prefetches a CD's artist, its liner notes (if present),
4492 the cover image, the tracks on that CD, and the guests on those
4495 my $rs = $schema->resultset('CD')->search(
4499 { artist => 'record_label'}, # belongs_to => belongs_to
4500 'liner_note', # might_have
4501 'cover_image', # has_one
4502 { tracks => 'guests' }, # has_many => has_many
4507 This will produce SQL like the following:
4509 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4513 ON artist.artistid = me.artistid
4514 JOIN record_label record_label
4515 ON record_label.labelid = artist.labelid
4516 LEFT JOIN track tracks
4517 ON tracks.cdid = me.cdid
4518 LEFT JOIN guest guests
4519 ON guests.trackid = track.trackid
4520 LEFT JOIN liner_notes liner_note
4521 ON liner_note.cdid = me.cdid
4522 JOIN cd_artwork cover_image
4523 ON cover_image.cdid = me.cdid
4526 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4527 C<tracks>, and C<guests> of the CD will all be available through the
4528 relationship accessors without the need for additional queries to the
4533 Prefetch does a lot of deep magic. As such, it may not behave exactly
4534 as you might expect.
4540 Prefetch uses the L</cache> to populate the prefetched relationships. This
4541 may or may not be what you want.
4545 If you specify a condition on a prefetched relationship, ONLY those
4546 rows that match the prefetched condition will be fetched into that relationship.
4547 This means that adding prefetch to a search() B<may alter> what is returned by
4548 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4550 my $artist_rs = $schema->resultset('Artist')->search({
4556 my $count = $artist_rs->first->cds->count;
4558 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4560 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4562 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4564 That cmp_ok() may or may not pass depending on the datasets involved. In other
4565 words the C<WHERE> condition would apply to the entire dataset, just like
4566 it would in regular SQL. If you want to add a condition only to the "right side"
4567 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4568 condition|DBIx::Class::Relationship::Base/condition>
4572 =head1 DBIC BIND VALUES
4574 Because DBIC may need more information to bind values than just the column name
4575 and value itself, it uses a special format for both passing and receiving bind
4576 values. Each bind value should be composed of an arrayref of
4577 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4583 If present (in any form), this is what is being passed directly to bind_param.
4584 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4585 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4587 If this is specified, all other bind options described below are ignored.
4591 If present, this is used to infer the actual bind attribute by passing to
4592 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4593 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4595 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4596 currently drivers are expected to "Do the Right Thing" when given a common
4597 datatype name. (Not ideal, but that's what we got at this point.)
4601 Currently used to correctly allocate buffers for bind_param_inout().
4602 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4603 or to a sensible value based on the "data_type".
4607 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4608 explicitly specified they are never overriden). Also used by some weird DBDs,
4609 where the column name should be available at bind_param time (e.g. Oracle).
4613 For backwards compatibility and convenience, the following shortcuts are
4616 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4617 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4618 [ undef, $val ] === [ {}, $val ]
4620 =head1 AUTHOR AND CONTRIBUTORS
4622 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4626 You may distribute this code under the same terms as Perl itself.