1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::ResultSetColumn;
8 use Scalar::Util qw/blessed weaken/;
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 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
32 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
36 my $users_rs = $schema->resultset('User');
37 while( $user = $users_rs->next) {
38 print $user->username;
41 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
42 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
46 A ResultSet is an object which stores a set of conditions representing
47 a query. It is the backbone of DBIx::Class (i.e. the really
48 important/useful bit).
50 No SQL is executed on the database when a ResultSet is created, it
51 just stores all the conditions needed to create the query.
53 A basic ResultSet representing the data of an entire table is returned
54 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
55 L<Source|DBIx::Class::Manual::Glossary/Source> name.
57 my $users_rs = $schema->resultset('User');
59 A new ResultSet is returned from calling L</search> on an existing
60 ResultSet. The new one will contain all the conditions of the
61 original, plus any new conditions added in the C<search> call.
63 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
64 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
67 The query that the ResultSet represents is B<only> executed against
68 the database when these methods are called:
69 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
71 If a resultset is used in a numeric context it returns the L</count>.
72 However, if it is used in a boolean context it is B<always> true. So if
73 you want to check if a resultset has any results, you must use C<if $rs
76 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
78 If you want to make your custom ResultSet classes with L<Moose>, use a template
81 package MyApp::Schema::ResultSet::User;
84 use namespace::autoclean;
86 extends 'DBIx::Class::ResultSet';
88 sub BUILDARGS { $_[2] }
92 __PACKAGE__->meta->make_immutable;
96 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
97 clash with the regular ResultSet constructor. Alternatively, you can use:
99 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
101 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
102 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
106 =head2 Chaining resultsets
108 Let's say you've got a query that needs to be run to return some data
109 to the user. But, you have an authorization system in place that
110 prevents certain users from seeing certain information. So, you want
111 to construct the basic query in one method, but add constraints to it in
116 my $request = $self->get_request; # Get a request object somehow.
117 my $schema = $self->result_source->schema;
119 my $cd_rs = $schema->resultset('CD')->search({
120 title => $request->param('title'),
121 year => $request->param('year'),
124 $cd_rs = $self->apply_security_policy( $cd_rs );
126 return $cd_rs->all();
129 sub apply_security_policy {
138 =head3 Resolving conditions and attributes
140 When a resultset is chained from another resultset (ie:
141 C<my $new_rs = $old_rs->search(\%extra_cond, \%attrs)>), conditions
142 and attributes with the same keys need resolving.
144 If any of L</columns>, L</select>, L</as> are present, they reset the
145 original selection, and start the selection "clean".
147 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
148 are merged into the existing ones from the original resultset.
150 The L</where> and L</having> attributes, and any search conditions, are
151 merged with an SQL C<AND> to the existing condition from the original
154 All other attributes are overridden by any new ones supplied in the
157 =head2 Multiple queries
159 Since a resultset just defines a query, you can do all sorts of
160 things with it with the same object.
162 # Don't hit the DB yet.
163 my $cd_rs = $schema->resultset('CD')->search({
164 title => 'something',
168 # Each of these hits the DB individually.
169 my $count = $cd_rs->count;
170 my $most_recent = $cd_rs->get_column('date_released')->max();
171 my @records = $cd_rs->all;
173 And it's not just limited to SELECT statements.
179 $cd_rs->create({ artist => 'Fred' });
181 Which is the same as:
183 $schema->resultset('CD')->create({
184 title => 'something',
189 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
197 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
199 =item Return Value: L<$resultset|/search>
203 The resultset constructor. Takes a source object (usually a
204 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
205 L</ATTRIBUTES> below). Does not perform any queries -- these are
206 executed as needed by the other methods.
208 Generally you never construct a resultset manually. Instead you get one
210 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
211 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
214 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
220 If called on an object, proxies to L</new_result> instead, so
222 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
224 will return a CD object, not a ResultSet, and is equivalent to:
226 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
228 Please also keep in mind that many internals call L</new_result> directly,
229 so overloading this method with the idea of intercepting new result object
230 creation B<will not work>. See also warning pertaining to L</create>.
238 return $class->new_result(@_) if ref $class;
240 my ($source, $attrs) = @_;
241 $source = $source->resolve
242 if $source->isa('DBIx::Class::ResultSourceHandle');
243 $attrs = { %{$attrs||{}} };
245 if ($attrs->{page}) {
246 $attrs->{rows} ||= 10;
249 $attrs->{alias} ||= 'me';
252 result_source => $source,
253 cond => $attrs->{where},
258 # if there is a dark selector, this means we are already in a
259 # chain and the cleanup/sanification was taken care of by
261 $self->_normalize_selection($attrs)
262 unless $attrs->{_dark_selector};
265 $attrs->{result_class} || $source->result_class
275 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
277 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
281 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
282 my $new_rs = $cd_rs->search({ year => 2005 });
284 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
285 # year = 2005 OR year = 2004
287 In list context, C<< ->all() >> is called implicitly on the resultset, thus
288 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
289 To avoid that, use L</search_rs>.
291 If you need to pass in additional attributes but no additional condition,
292 call it as C<search(undef, \%attrs)>.
294 # "SELECT name, artistid FROM $artist_table"
295 my @all_artists = $schema->resultset('Artist')->search(undef, {
296 columns => [qw/name artistid/],
299 For a list of attributes that can be passed to C<search>, see
300 L</ATTRIBUTES>. For more examples of using this function, see
301 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
302 documentation for the first argument, see L<SQL::Abstract>
303 and its extension L<DBIx::Class::SQLMaker>.
305 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
309 Note that L</search> does not process/deflate any of the values passed in the
310 L<SQL::Abstract>-compatible search condition structure. This is unlike other
311 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
312 manually that any value passed to this method will stringify to something the
313 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
314 objects, for more info see:
315 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
321 my $rs = $self->search_rs( @_ );
326 elsif (defined wantarray) {
330 # we can be called by a relationship helper, which in
331 # turn may be called in void context due to some braindead
332 # overload or whatever else the user decided to be clever
333 # at this particular day. Thus limit the exception to
334 # external code calls only
335 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
336 if (caller)[0] !~ /^\QDBIx::Class::/;
346 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
348 =item Return Value: L<$resultset|/search>
352 This method does the same exact thing as search() except it will
353 always return a resultset, even in list context.
360 my $rsrc = $self->result_source;
361 my ($call_cond, $call_attrs);
363 # Special-case handling for (undef, undef) or (undef)
364 # Note that (foo => undef) is valid deprecated syntax
365 @_ = () if not scalar grep { defined $_ } @_;
371 # fish out attrs in the ($condref, $attr) case
372 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
373 ($call_cond, $call_attrs) = @_;
376 $self->throw_exception('Odd number of arguments to search')
380 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
381 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
383 for my $i (0 .. $#_) {
385 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
386 if (! defined $_[$i] or ref $_[$i] ne '');
392 # see if we can keep the cache (no $rs changes)
394 my %safe = (alias => 1, cache => 1);
395 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
398 ref $_[0] eq 'HASH' && ! keys %{$_[0]}
400 ref $_[0] eq 'ARRAY' && ! @{$_[0]}
402 $cache = $self->get_cache;
405 my $old_attrs = { %{$self->{attrs}} };
406 my $old_having = delete $old_attrs->{having};
407 my $old_where = delete $old_attrs->{where};
409 my $new_attrs = { %$old_attrs };
411 # take care of call attrs (only if anything is changing)
412 if ($call_attrs and keys %$call_attrs) {
414 # copy for _normalize_selection
415 $call_attrs = { %$call_attrs };
417 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
419 # reset the current selector list if new selectors are supplied
420 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
421 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
424 # Normalize the new selector list (operates on the passed-in attr structure)
425 # Need to do it on every chain instead of only once on _resolved_attrs, in
426 # order to allow detection of empty vs partial 'as'
427 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
428 if $old_attrs->{_dark_selector};
429 $self->_normalize_selection ($call_attrs);
431 # start with blind overwriting merge, exclude selector attrs
432 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
433 delete @{$new_attrs}{@selector_attrs};
435 for (@selector_attrs) {
436 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
437 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
440 # older deprecated name, use only if {columns} is not there
441 if (my $c = delete $new_attrs->{cols}) {
442 if ($new_attrs->{columns}) {
443 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
446 $new_attrs->{columns} = $c;
451 # join/prefetch use their own crazy merging heuristics
452 foreach my $key (qw/join prefetch/) {
453 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
454 if exists $call_attrs->{$key};
457 # stack binds together
458 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
462 for ($old_where, $call_cond) {
464 $new_attrs->{where} = $self->_stack_cond (
465 $_, $new_attrs->{where}
470 if (defined $old_having) {
471 $new_attrs->{having} = $self->_stack_cond (
472 $old_having, $new_attrs->{having}
476 my $rs = (ref $self)->new($rsrc, $new_attrs);
478 $rs->set_cache($cache) if ($cache);
484 sub _normalize_selection {
485 my ($self, $attrs) = @_;
488 $attrs->{'+columns'} = $self->_merge_attr($attrs->{'+columns'}, delete $attrs->{include_columns})
489 if exists $attrs->{include_columns};
491 # columns are always placed first, however
493 # Keep the X vs +X separation until _resolved_attrs time - this allows to
494 # delay the decision on whether to use a default select list ($rsrc->columns)
495 # allowing stuff like the remove_columns helper to work
497 # select/as +select/+as pairs need special handling - the amount of select/as
498 # elements in each pair does *not* have to be equal (think multicolumn
499 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
500 # supplied at all) - try to infer the alias, either from the -as parameter
501 # of the selector spec, or use the parameter whole if it looks like a column
502 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
503 # is ok as well), but make sure no more additions to the 'as' chain take place
504 for my $pref ('', '+') {
506 my ($sel, $as) = map {
507 my $key = "${pref}${_}";
509 my $val = [ ref $attrs->{$key} eq 'ARRAY'
511 : $attrs->{$key} || ()
513 delete $attrs->{$key};
517 if (! @$as and ! @$sel ) {
520 elsif (@$as and ! @$sel) {
521 $self->throw_exception(
522 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
526 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
527 # if any @$as has been supplied we assume the user knows what (s)he is doing
528 # and blindly keep stacking up pieces
529 unless ($attrs->{_dark_selector}) {
532 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
533 push @$as, $_->{-as};
535 # assume any plain no-space, no-parenthesis string to be a column spec
536 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
537 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
540 # if all else fails - raise a flag that no more aliasing will be allowed
542 $attrs->{_dark_selector} = {
544 string => ($dark_sel_dumper ||= do {
545 require Data::Dumper::Concise;
546 Data::Dumper::Concise::DumperObject()->Indent(0);
547 })->Values([$_])->Dump
555 elsif (@$as < @$sel) {
556 $self->throw_exception(
557 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
560 elsif ($pref and $attrs->{_dark_selector}) {
561 $self->throw_exception(
562 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
568 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
569 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
574 my ($self, $left, $right) = @_;
576 # collapse single element top-level conditions
577 # (single pass only, unlikely to need recursion)
578 for ($left, $right) {
579 if (ref $_ eq 'ARRAY') {
587 elsif (ref $_ eq 'HASH') {
588 my ($first, $more) = keys %$_;
591 if (! defined $first) {
595 elsif (! defined $more) {
596 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
599 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
606 # merge hashes with weeding out of duplicates (simple cases only)
607 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
609 # shallow copy to destroy
610 $right = { %$right };
611 for (grep { exists $right->{$_} } keys %$left) {
612 # the use of eq_deeply here is justified - the rhs of an
613 # expression can contain a lot of twisted weird stuff
614 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
617 $right = undef unless keys %$right;
621 if (defined $left xor defined $right) {
622 return defined $left ? $left : $right;
624 elsif (! defined $left) {
628 return { -and => [ $left, $right ] };
632 =head2 search_literal
634 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
635 should only be used in that context. C<search_literal> is a convenience
636 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
637 want to ensure columns are bound correctly, use L</search>.
639 See L<DBIx::Class::Manual::Cookbook/Searching> and
640 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
641 require C<search_literal>.
645 =item Arguments: $sql_fragment, @standalone_bind_values
647 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
651 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
652 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
654 Pass a literal chunk of SQL to be added to the conditional part of the
657 Example of how to use C<search> instead of C<search_literal>
659 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
660 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
665 my ($self, $sql, @bind) = @_;
667 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
670 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
677 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
679 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
683 Finds and returns a single row based on supplied criteria. Takes either a
684 hashref with the same format as L</create> (including inference of foreign
685 keys from related objects), or a list of primary key values in the same
686 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
687 declaration on the L</result_source>.
689 In either case an attempt is made to combine conditions already existing on
690 the resultset with the condition passed to this method.
692 To aid with preparing the correct query for the storage you may supply the
693 C<key> attribute, which is the name of a
694 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
695 unique constraint corresponding to the
696 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
697 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
698 to construct a query that satisfies the named unique constraint fully (
699 non-NULL values for each column member of the constraint) an exception is
702 If no C<key> is specified, the search is carried over all unique constraints
703 which are fully defined by the available condition.
705 If no such constraint is found, C<find> currently defaults to a simple
706 C<< search->(\%column_values) >> which may or may not do what you expect.
707 Note that this fallback behavior may be deprecated in further versions. If
708 you need to search with arbitrary conditions - use L</search>. If the query
709 resulting from this fallback produces more than one row, a warning to the
710 effect is issued, though only the first row is constructed and returned as
713 In addition to C<key>, L</find> recognizes and applies standard
714 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
716 Note that if you have extra concerns about the correctness of the resulting
717 query you need to specify the C<key> attribute and supply the entire condition
718 as an argument to find (since it is not always possible to perform the
719 combination of the resultset condition with the supplied one, especially if
720 the resultset condition contains literal sql).
722 For example, to find a row by its primary key:
724 my $cd = $schema->resultset('CD')->find(5);
726 You can also find a row by a specific unique constraint:
728 my $cd = $schema->resultset('CD')->find(
730 artist => 'Massive Attack',
731 title => 'Mezzanine',
733 { key => 'cd_artist_title' }
736 See also L</find_or_create> and L</update_or_create>.
742 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
744 my $rsrc = $self->result_source;
747 if (exists $attrs->{key}) {
748 $constraint_name = defined $attrs->{key}
750 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
754 # Parse out the condition from input
757 if (ref $_[0] eq 'HASH') {
758 $call_cond = { %{$_[0]} };
761 # if only values are supplied we need to default to 'primary'
762 $constraint_name = 'primary' unless defined $constraint_name;
764 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
766 $self->throw_exception(
767 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
770 $self->throw_exception (
771 'find() expects either a column/value hashref, or a list of values '
772 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
773 ) unless @c_cols == @_;
776 @{$call_cond}{@c_cols} = @_;
780 for my $key (keys %$call_cond) {
782 my $keyref = ref($call_cond->{$key})
784 my $relinfo = $rsrc->relationship_info($key)
786 my $val = delete $call_cond->{$key};
788 next if $keyref eq 'ARRAY'; # has_many for multi_create
790 my $rel_q = $rsrc->_resolve_condition(
791 $relinfo->{cond}, $val, $key, $key
793 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
794 @related{keys %$rel_q} = values %$rel_q;
798 # relationship conditions take precedence (?)
799 @{$call_cond}{keys %related} = values %related;
801 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
803 if (defined $constraint_name) {
804 $final_cond = $self->_qualify_cond_columns (
806 $self->_build_unique_cond (
814 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
815 # This means that we got here after a merger of relationship conditions
816 # in ::Relationship::Base::search_related (the row method), and furthermore
817 # the relationship is of the 'single' type. This means that the condition
818 # provided by the relationship (already attached to $self) is sufficient,
819 # as there can be only one row in the database that would satisfy the
823 # no key was specified - fall down to heuristics mode:
824 # run through all unique queries registered on the resultset, and
825 # 'OR' all qualifying queries together
826 my (@unique_queries, %seen_column_combinations);
827 for my $c_name ($rsrc->unique_constraint_names) {
828 next if $seen_column_combinations{
829 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
832 push @unique_queries, try {
833 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
837 $final_cond = @unique_queries
838 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
839 : $self->_non_unique_find_fallback ($call_cond, $attrs)
843 # Run the query, passing the result_class since it should propagate for find
844 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
845 if ($rs->_resolved_attrs->{collapse}) {
847 carp "Query returned more than one row" if $rs->next;
855 # This is a stop-gap method as agreed during the discussion on find() cleanup:
856 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
858 # It is invoked when find() is called in legacy-mode with insufficiently-unique
859 # condition. It is provided for overrides until a saner way forward is devised
861 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
862 # the road. Please adjust your tests accordingly to catch this situation early
863 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
865 # The method will not be removed without an adequately complete replacement
866 # for strict-mode enforcement
867 sub _non_unique_find_fallback {
868 my ($self, $cond, $attrs) = @_;
870 return $self->_qualify_cond_columns(
872 exists $attrs->{alias}
874 : $self->{attrs}{alias}
879 sub _qualify_cond_columns {
880 my ($self, $cond, $alias) = @_;
882 my %aliased = %$cond;
883 for (keys %aliased) {
884 $aliased{"$alias.$_"} = delete $aliased{$_}
891 sub _build_unique_cond {
892 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
894 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
896 # combination may fail if $self->{cond} is non-trivial
897 my ($final_cond) = try {
898 $self->_merge_with_rscond ($extra_cond)
903 # trim out everything not in $columns
904 $final_cond = { map {
905 exists $final_cond->{$_}
906 ? ( $_ => $final_cond->{$_} )
910 if (my @missing = grep
911 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
914 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
916 join (', ', map { "'$_'" } @missing),
923 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
925 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
927 carp_unique ( sprintf (
928 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
929 . 'values in column(s): %s). This is almost certainly not what you wanted, '
930 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
932 join (', ', map { "'$_'" } @undefs),
939 =head2 search_related
943 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
945 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
949 $new_rs = $cd_rs->search_related('artist', {
953 Searches the specified relationship, optionally specifying a condition and
954 attributes for matching records. See L</ATTRIBUTES> for more information.
956 In list context, C<< ->all() >> is called implicitly on the resultset, thus
957 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
959 See also L</search_related_rs>.
964 return shift->related_resultset(shift)->search(@_);
967 =head2 search_related_rs
969 This method works exactly the same as search_related, except that
970 it guarantees a resultset, even in list context.
974 sub search_related_rs {
975 return shift->related_resultset(shift)->search_rs(@_);
982 =item Arguments: none
984 =item Return Value: L<$cursor|DBIx::Class::Cursor>
988 Returns a storage-driven cursor to the given resultset. See
989 L<DBIx::Class::Cursor> for more information.
996 return $self->{cursor} ||= do {
997 my $attrs = { %{$self->_resolved_attrs } };
998 $self->result_source->storage->select(
999 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1008 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1010 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1014 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1016 Inflates the first result without creating a cursor if the resultset has
1017 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1020 While this method can take an optional search condition (just like L</search>)
1021 being a fast-code-path it does not recognize search attributes. If you need to
1022 add extra joins or similar, call L</search> and then chain-call L</single> on the
1023 L<DBIx::Class::ResultSet> returned.
1029 As of 0.08100, this method enforces the assumption that the preceding
1030 query returns only one row. If more than one row is returned, you will receive
1033 Query returned more than one row
1035 In this case, you should be using L</next> or L</find> instead, or if you really
1036 know what you are doing, use the L</rows> attribute to explicitly limit the size
1039 This method will also throw an exception if it is called on a resultset prefetching
1040 has_many, as such a prefetch implies fetching multiple rows from the database in
1041 order to assemble the resulting object.
1048 my ($self, $where) = @_;
1050 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1053 my $attrs = { %{$self->_resolved_attrs} };
1055 $self->throw_exception(
1056 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
1057 ) if $attrs->{collapse};
1060 if (defined $attrs->{where}) {
1063 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1064 $where, delete $attrs->{where} ]
1067 $attrs->{where} = $where;
1071 my $data = [ $self->result_source->storage->select_single(
1072 $attrs->{from}, $attrs->{select},
1073 $attrs->{where}, $attrs
1075 return undef unless @$data;
1076 $self->{stashed_rows} = [ $data ];
1077 $self->_construct_objects->[0];
1083 # Recursively collapse the query, accumulating values for each column.
1085 sub _collapse_query {
1086 my ($self, $query, $collapsed) = @_;
1090 if (ref $query eq 'ARRAY') {
1091 foreach my $subquery (@$query) {
1092 next unless ref $subquery; # -or
1093 $collapsed = $self->_collapse_query($subquery, $collapsed);
1096 elsif (ref $query eq 'HASH') {
1097 if (keys %$query and (keys %$query)[0] eq '-and') {
1098 foreach my $subquery (@{$query->{-and}}) {
1099 $collapsed = $self->_collapse_query($subquery, $collapsed);
1103 foreach my $col (keys %$query) {
1104 my $value = $query->{$col};
1105 $collapsed->{$col}{$value}++;
1117 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1119 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1123 my $max_length = $rs->get_column('length')->max;
1125 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1130 my ($self, $column) = @_;
1131 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1139 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1141 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1145 # WHERE title LIKE '%blue%'
1146 $cd_rs = $rs->search_like({ title => '%blue%'});
1148 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1149 that this is simply a convenience method retained for ex Class::DBI users.
1150 You most likely want to use L</search> with specific operators.
1152 For more information, see L<DBIx::Class::Manual::Cookbook>.
1154 This method is deprecated and will be removed in 0.09. Use L</search()>
1155 instead. An example conversion is:
1157 ->search_like({ foo => 'bar' });
1161 ->search({ foo => { like => 'bar' } });
1168 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1169 .' Instead use ->search({ x => { -like => "y%" } })'
1170 .' (note the outer pair of {}s - they are important!)'
1172 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1173 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1174 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1175 return $class->search($query, { %$attrs });
1182 =item Arguments: $first, $last
1184 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1188 Returns a resultset or object list representing a subset of elements from the
1189 resultset slice is called on. Indexes are from 0, i.e., to get the first
1190 three records, call:
1192 my ($one, $two, $three) = $rs->slice(0, 2);
1197 my ($self, $min, $max) = @_;
1198 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1199 $attrs->{offset} = $self->{attrs}{offset} || 0;
1200 $attrs->{offset} += $min;
1201 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1202 return $self->search(undef, $attrs);
1203 #my $slice = (ref $self)->new($self->result_source, $attrs);
1204 #return (wantarray ? $slice->all : $slice);
1211 =item Arguments: none
1213 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1217 Returns the next element in the resultset (C<undef> is there is none).
1219 Can be used to efficiently iterate over records in the resultset:
1221 my $rs = $schema->resultset('CD')->search;
1222 while (my $cd = $rs->next) {
1226 Note that you need to store the resultset object, and call C<next> on it.
1227 Calling C<< resultset('Table')->next >> repeatedly will always return the
1228 first record from the resultset.
1235 if (my $cache = $self->get_cache) {
1236 $self->{all_cache_position} ||= 0;
1237 return $cache->[$self->{all_cache_position}++];
1240 if ($self->{attrs}{cache}) {
1241 delete $self->{pager};
1242 $self->{all_cache_position} = 1;
1243 return ($self->all)[0];
1246 return shift(@{$self->{stashed_objects}}) if @{ $self->{stashed_objects}||[] };
1248 $self->{stashed_objects} = $self->_construct_objects
1251 return shift @{$self->{stashed_objects}};
1254 # Constructs as many objects as it can in one pass while respecting
1255 # cursor laziness. Several modes of operation:
1257 # * Always builds everything present in @{$self->{stashed_rows}}
1258 # * If called with $fetch_all true - pulls everything off the cursor and
1259 # builds all objects in one pass
1260 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1261 # and if the resultset is ordered properly by the left side:
1262 # * Fetches stuff off the cursor until the "master object" changes,
1263 # and saves the last extra row (if any) in @{$self->{stashed_rows}}
1265 # * Just fetches, and collapses/constructs everything as if $fetch_all
1266 # was requested (there is no other way to collapse except for an
1268 # * If no collapse is requested - just get the next row, construct and
1270 sub _construct_objects {
1271 my ($self, $fetch_all) = @_;
1273 my $rsrc = $self->result_source;
1274 my $attrs = $self->_resolved_attrs;
1276 if (!$fetch_all and ! $attrs->{order_by} and $attrs->{collapse}) {
1277 # default order for collapsing unless the user asked for something
1278 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} $rsrc->primary_columns ];
1279 $attrs->{_ordered_for_collapse} = 1;
1280 $attrs->{_order_is_artificial} = 1;
1283 my $cursor = $self->cursor;
1285 # this will be used as both initial raw-row collector AND as a RV of
1286 # _construct_objects. Not regrowing the array twice matters a lot...
1287 # a suprising amount actually
1288 my $rows = delete $self->{stashed_rows};
1291 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1292 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1294 elsif( $attrs->{collapse} ) {
1296 $attrs->{_ordered_for_collapse} = (!$attrs->{order_by}) ? 0 : do {
1297 my $st = $rsrc->schema->storage;
1300 ( $st->_extract_order_criteria($attrs->{order_by}) )
1303 my $colinfos = $st->_resolve_column_info($attrs->{from}, \@ord_cols);
1305 for (0 .. $#ord_cols) {
1307 ! $colinfos->{$ord_cols[$_]}
1309 $colinfos->{$ord_cols[$_]}{-result_source} != $rsrc
1311 splice @ord_cols, $_;
1316 # since all we check here are the start of the order_by belonging to the
1317 # top level $rsrc, a present identifying set will mean that the resultset
1318 # is ordered by its leftmost table in a tsable manner
1319 (@ord_cols and $rsrc->_identifying_column_set({ map
1320 { $colinfos->{$_}{-colname} => $colinfos->{$_} }
1323 } unless defined $attrs->{_ordered_for_collapse};
1325 if (! $attrs->{_ordered_for_collapse}) {
1328 # instead of looping over ->next, use ->all in stealth mode
1329 # *without* calling a ->reset afterwards
1330 # FIXME - encapsulation breach, got to be a better way
1331 if (! $cursor->{_done}) {
1332 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1333 $cursor->{_done} = 1;
1338 if (! $fetch_all and ! @{$rows||[]} ) {
1339 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1340 if (scalar (my @r = $cursor->next) ) {
1345 return undef unless @{$rows||[]};
1347 my @extra_collapser_args;
1348 if ($attrs->{collapse} and ! $fetch_all ) {
1350 @extra_collapser_args = (
1351 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1352 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1353 ($self->{stashed_rows} = []), # where does it stuff excess
1357 # hotspot - skip the setter
1358 my $res_class = $self->_result_class;
1360 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1361 $res_class->can ('inflate_result')
1362 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1365 my $infmap = $attrs->{as};
1367 $self->{_result_inflator}{is_hri} = do { ( $inflator_cref == (
1368 require DBIx::Class::ResultClass::HashRefInflator
1370 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1372 } unless defined $self->{_result_inflator}{is_hri};
1374 if ($attrs->{_single_resultclass_inflation}) {
1375 # construct a much simpler array->hash folder for the one-table cases right here
1376 if ($self->{_result_inflator}{is_hri}) {
1377 for my $r (@$rows) {
1378 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1381 # FIXME SUBOPTIMAL this is a very very very hot spot
1382 # while rather optimal we can *still* do much better, by
1383 # building a smarter Row::inflate_result(), and
1384 # switch to feeding it data via a much leaner interface
1386 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1387 # this particular resultset size
1388 elsif (@$rows < 60) {
1389 for my $r (@$rows) {
1390 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1395 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1396 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1400 # Special-case multi-object HRI (we always prune)
1401 elsif ($self->{_result_inflator}{is_hri}) {
1402 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1404 inflate_map => $infmap,
1405 selection => $attrs->{select},
1406 collapse => $attrs->{collapse},
1407 premultiplied => $attrs->{_main_source_premultiplied},
1409 }) )->($rows, @extra_collapser_args);
1411 # Regular multi-object
1414 ( $self->{_row_parser}{classic} ||= $rsrc->_mk_row_parser({
1416 inflate_map => $infmap,
1417 selection => $attrs->{select},
1418 collapse => $attrs->{collapse},
1419 premultiplied => $attrs->{_main_source_premultiplied},
1420 }) )->($rows, @extra_collapser_args);
1422 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1426 if ($attrs->{record_filter}) {
1427 $_ = $attrs->{record_filter}->($_) for @$rows;
1433 =head2 result_source
1437 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1439 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1443 An accessor for the primary ResultSource object from which this ResultSet
1450 =item Arguments: $result_class?
1452 =item Return Value: $result_class
1456 An accessor for the class to use when creating result objects. Defaults to
1457 C<< result_source->result_class >> - which in most cases is the name of the
1458 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1460 Note that changing the result_class will also remove any components
1461 that were originally loaded in the source class via
1462 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1463 in the original source class will not run.
1468 my ($self, $result_class) = @_;
1469 if ($result_class) {
1471 unless (ref $result_class) { # don't fire this for an object
1472 $self->ensure_class_loaded($result_class);
1474 $self->_result_class($result_class);
1475 # THIS LINE WOULD BE A BUG - this accessor specifically exists to
1476 # permit the user to set result class on one result set only; it only
1477 # chains if provided to search()
1478 #$self->{attrs}{result_class} = $result_class if ref $self;
1480 delete $self->{_result_inflator};
1482 $self->_result_class;
1489 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1491 =item Return Value: $count
1495 Performs an SQL C<COUNT> with the same query as the resultset was built
1496 with to find the number of elements. Passing arguments is equivalent to
1497 C<< $rs->search ($cond, \%attrs)->count >>
1503 return $self->search(@_)->count if @_ and defined $_[0];
1504 return scalar @{ $self->get_cache } if $self->get_cache;
1506 my $attrs = { %{ $self->_resolved_attrs } };
1508 # this is a little optimization - it is faster to do the limit
1509 # adjustments in software, instead of a subquery
1510 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1513 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1514 $crs = $self->_count_subq_rs ($attrs);
1517 $crs = $self->_count_rs ($attrs);
1519 my $count = $crs->next;
1521 $count -= $offset if $offset;
1522 $count = $rows if $rows and $rows < $count;
1523 $count = 0 if ($count < 0);
1532 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1534 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1538 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1539 This can be very handy for subqueries:
1541 ->search( { amount => $some_rs->count_rs->as_query } )
1543 As with regular resultsets the SQL query will be executed only after
1544 the resultset is accessed via L</next> or L</all>. That would return
1545 the same single value obtainable via L</count>.
1551 return $self->search(@_)->count_rs if @_;
1553 # this may look like a lack of abstraction (count() does about the same)
1554 # but in fact an _rs *must* use a subquery for the limits, as the
1555 # software based limiting can not be ported if this $rs is to be used
1556 # in a subquery itself (i.e. ->as_query)
1557 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1558 return $self->_count_subq_rs;
1561 return $self->_count_rs;
1566 # returns a ResultSetColumn object tied to the count query
1569 my ($self, $attrs) = @_;
1571 my $rsrc = $self->result_source;
1572 $attrs ||= $self->_resolved_attrs;
1574 my $tmp_attrs = { %$attrs };
1575 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1576 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1578 # overwrite the selector (supplied by the storage)
1579 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1580 $tmp_attrs->{as} = 'count';
1582 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1588 # same as above but uses a subquery
1590 sub _count_subq_rs {
1591 my ($self, $attrs) = @_;
1593 my $rsrc = $self->result_source;
1594 $attrs ||= $self->_resolved_attrs;
1596 my $sub_attrs = { %$attrs };
1597 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1598 delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/};
1600 # if we multi-prefetch we group_by something unique, as this is what we would
1601 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1602 if ( $attrs->{collapse} ) {
1603 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1604 $rsrc->_identifying_column_set || $self->throw_exception(
1605 'Unable to construct a unique group_by criteria properly collapsing the '
1606 . 'has_many prefetch before count()'
1611 # Calculate subquery selector
1612 if (my $g = $sub_attrs->{group_by}) {
1614 my $sql_maker = $rsrc->storage->sql_maker;
1616 # necessary as the group_by may refer to aliased functions
1618 for my $sel (@{$attrs->{select}}) {
1619 $sel_index->{$sel->{-as}} = $sel
1620 if (ref $sel eq 'HASH' and $sel->{-as});
1623 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1624 # also look for named aggregates referred in the having clause
1625 # having often contains scalarrefs - thus parse it out entirely
1627 if ($attrs->{having}) {
1628 local $sql_maker->{having_bind};
1629 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1630 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1631 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1632 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1633 # if we don't unset it we screw up retarded but unfortunately working
1634 # 'MAX(foo.bar)' => { '>', 3 }
1635 $sql_maker->{name_sep} = '';
1638 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1640 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1643 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1644 # and if all fails for an utterly naive quoted scalar-with-function
1645 while ($having_sql =~ /
1646 $rquote $sep $lquote (.+?) $rquote
1648 [\s,] \w+ \. (\w+) [\s,]
1650 [\s,] $lquote (.+?) $rquote [\s,]
1652 my $part = $1 || $2 || $3; # one of them matched if we got here
1653 unless ($seen_having{$part}++) {
1660 my $colpiece = $sel_index->{$_} || $_;
1662 # unqualify join-based group_by's. Arcane but possible query
1663 # also horrible horrible hack to alias a column (not a func.)
1664 # (probably need to introduce SQLA syntax)
1665 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1668 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1670 push @{$sub_attrs->{select}}, $colpiece;
1674 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1675 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1678 return $rsrc->resultset_class
1679 ->new ($rsrc, $sub_attrs)
1681 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1682 ->get_column ('count');
1689 =head2 count_literal
1691 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1692 should only be used in that context. See L</search_literal> for further info.
1696 =item Arguments: $sql_fragment, @standalone_bind_values
1698 =item Return Value: $count
1702 Counts the results in a literal query. Equivalent to calling L</search_literal>
1703 with the passed arguments, then L</count>.
1707 sub count_literal { shift->search_literal(@_)->count; }
1713 =item Arguments: none
1715 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1719 Returns all elements in the resultset.
1726 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1729 delete @{$self}{qw/stashed_rows stashed_objects/};
1731 if (my $c = $self->get_cache) {
1735 $self->cursor->reset;
1737 my $objs = $self->_construct_objects('fetch_all') || [];
1739 $self->set_cache($objs) if $self->{attrs}{cache};
1748 =item Arguments: none
1750 =item Return Value: $self
1754 Resets the resultset's cursor, so you can iterate through the elements again.
1755 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1763 delete @{$self}{qw/stashed_rows stashed_objects/};
1764 $self->{all_cache_position} = 0;
1765 $self->cursor->reset;
1773 =item Arguments: none
1775 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1779 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1780 an object for the first result (or C<undef> if the resultset is empty).
1785 return $_[0]->reset->next;
1791 # Determines whether and what type of subquery is required for the $rs operation.
1792 # If grouping is necessary either supplies its own, or verifies the current one
1793 # After all is done delegates to the proper storage method.
1795 sub _rs_update_delete {
1796 my ($self, $op, $values) = @_;
1798 my $rsrc = $self->result_source;
1799 my $storage = $rsrc->schema->storage;
1801 my $attrs = { %{$self->_resolved_attrs} };
1803 my $join_classifications;
1804 my $existing_group_by = delete $attrs->{group_by};
1806 # do we need a subquery for any reason?
1808 defined $existing_group_by
1810 # if {from} is unparseable wrap a subq
1811 ref($attrs->{from}) ne 'ARRAY'
1813 # limits call for a subq
1814 $self->_has_resolved_attr(qw/rows offset/)
1817 # simplify the joinmap, so we can further decide if a subq is necessary
1818 if (!$needs_subq and @{$attrs->{from}} > 1) {
1819 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1821 # check if there are any joins left after the prune
1822 if ( @{$attrs->{from}} > 1 ) {
1823 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1824 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1830 # any non-pruneable joins imply subq
1831 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1835 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1837 (ref $attrs->{from}[0]) ne 'HASH'
1839 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1843 # do we need anything like a subquery?
1844 if (! $needs_subq) {
1845 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1846 # a condition containing 'me' or other table prefixes will not work
1847 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1849 my $sqla = $rsrc->storage->sql_maker;
1850 local $sqla->{_dequalify_idents} = 1;
1851 \[ $sqla->_recurse_where($self->{cond}) ];
1855 # we got this far - means it is time to wrap a subquery
1856 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1858 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1864 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1865 delete $attrs->{$_} for qw/collapse select _prefetch_selector_range as/;
1866 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1867 $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins
1868 my $subrs = (ref $self)->new($rsrc, $attrs);
1870 if (@$idcols == 1) {
1871 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1873 elsif ($storage->_use_multicolumn_in) {
1874 # no syntax for calling this properly yet
1875 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1876 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1877 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1882 # if all else fails - get all primary keys and operate over a ORed set
1883 # wrap in a transaction for consistency
1884 # this is where the group_by/multiplication starts to matter
1888 keys %{ $join_classifications->{multiplying} || {} }
1890 # make sure if there is a supplied group_by it matches the columns compiled above
1891 # perfectly. Anything else can not be sanely executed on most databases so croak
1892 # right then and there
1893 if ($existing_group_by) {
1894 my @current_group_by = map
1895 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1900 join ("\x00", sort @current_group_by)
1902 join ("\x00", sort @{$attrs->{columns}} )
1904 $self->throw_exception (
1905 "You have just attempted a $op operation on a resultset which does group_by"
1906 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1907 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1908 . ' kind of queries. Please retry the operation with a modified group_by or'
1909 . ' without using one at all.'
1914 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1917 $guard = $storage->txn_scope_guard;
1920 for my $row ($subrs->cursor->all) {
1922 { $idcols->[$_] => $row->[$_] }
1929 my $res = $storage->$op (
1931 $op eq 'update' ? $values : (),
1935 $guard->commit if $guard;
1944 =item Arguments: \%values
1946 =item Return Value: $underlying_storage_rv
1950 Sets the specified columns in the resultset to the supplied values in a
1951 single query. Note that this will not run any accessor/set_column/update
1952 triggers, nor will it update any result object instances derived from this
1953 resultset (this includes the contents of the L<resultset cache|/set_cache>
1954 if any). See L</update_all> if you need to execute any on-update
1955 triggers or cascades defined either by you or a
1956 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1958 The return value is a pass through of what the underlying
1959 storage backend returned, and may vary. See L<DBI/execute> for the most
1964 Note that L</update> does not process/deflate any of the values passed in.
1965 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1966 ensure manually that any value passed to this method will stringify to
1967 something the RDBMS knows how to deal with. A notable example is the
1968 handling of L<DateTime> objects, for more info see:
1969 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1974 my ($self, $values) = @_;
1975 $self->throw_exception('Values for update must be a hash')
1976 unless ref $values eq 'HASH';
1978 return $self->_rs_update_delete ('update', $values);
1985 =item Arguments: \%values
1987 =item Return Value: 1
1991 Fetches all objects and updates them one at a time via
1992 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
1993 triggers, while L</update> will not.
1998 my ($self, $values) = @_;
1999 $self->throw_exception('Values for update_all must be a hash')
2000 unless ref $values eq 'HASH';
2002 my $guard = $self->result_source->schema->txn_scope_guard;
2003 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2012 =item Arguments: none
2014 =item Return Value: $underlying_storage_rv
2018 Deletes the rows matching this resultset in a single query. Note that this
2019 will not run any delete triggers, nor will it alter the
2020 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2021 derived from this resultset (this includes the contents of the
2022 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2023 execute any on-delete triggers or cascades defined either by you or a
2024 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2026 The return value is a pass through of what the underlying storage backend
2027 returned, and may vary. See L<DBI/execute> for the most common case.
2033 $self->throw_exception('delete does not accept any arguments')
2036 return $self->_rs_update_delete ('delete');
2043 =item Arguments: none
2045 =item Return Value: 1
2049 Fetches all objects and deletes them one at a time via
2050 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2051 triggers, while L</delete> will not.
2057 $self->throw_exception('delete_all does not accept any arguments')
2060 my $guard = $self->result_source->schema->txn_scope_guard;
2061 $_->delete for $self->all;
2070 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2072 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2076 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2083 The context of this method call has an important effect on what is
2084 submitted to storage. In void context data is fed directly to fastpath
2085 insertion routines provided by the underlying storage (most often
2086 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2087 L<insert|DBIx::Class::Row/insert> calls on the
2088 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2089 augmentation of these methods provided by components. For example if you
2090 are using something like L<DBIx::Class::UUIDColumns> to create primary
2091 keys for you, you will find that your PKs are empty. In this case you
2092 will have to explicitly force scalar or list context in order to create
2097 In non-void (scalar or list) context, this method is simply a wrapper
2098 for L</create>. Depending on list or scalar context either a list of
2099 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2100 containing these objects is returned.
2102 When supplying data in "arrayref of arrayrefs" invocation style, the
2103 first element should be a list of column names and each subsequent
2104 element should be a data value in the earlier specified column order.
2107 $Arstist_rs->populate([
2108 [ qw( artistid name ) ],
2109 [ 100, 'A Formally Unknown Singer' ],
2110 [ 101, 'A singer that jumped the shark two albums ago' ],
2111 [ 102, 'An actually cool singer' ],
2114 For the arrayref of hashrefs style each hashref should be a structure
2115 suitable for passing to L</create>. Multi-create is also permitted with
2118 $schema->resultset("Artist")->populate([
2119 { artistid => 4, name => 'Manufactured Crap', cds => [
2120 { title => 'My First CD', year => 2006 },
2121 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2124 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2125 { title => 'My parents sold me to a record company', year => 2005 },
2126 { title => 'Why Am I So Ugly?', year => 2006 },
2127 { title => 'I Got Surgery and am now Popular', year => 2007 }
2132 If you attempt a void-context multi-create as in the example above (each
2133 Artist also has the related list of CDs), and B<do not> supply the
2134 necessary autoinc foreign key information, this method will proxy to the
2135 less efficient L</create>, and then throw the Result objects away. In this
2136 case there are obviously no benefits to using this method over L</create>.
2143 # cruft placed in standalone method
2144 my $data = $self->_normalize_populate_args(@_);
2146 return unless @$data;
2148 if(defined wantarray) {
2149 my @created = map { $self->create($_) } @$data;
2150 return wantarray ? @created : \@created;
2153 my $first = $data->[0];
2155 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2156 # it relationship data
2157 my (@rels, @columns);
2158 my $rsrc = $self->result_source;
2159 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2160 for (keys %$first) {
2161 my $ref = ref $first->{$_};
2162 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2168 my @pks = $rsrc->primary_columns;
2170 ## do the belongs_to relationships
2171 foreach my $index (0..$#$data) {
2173 # delegate to create() for any dataset without primary keys with specified relationships
2174 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2176 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2177 my @ret = $self->populate($data);
2183 foreach my $rel (@rels) {
2184 next unless ref $data->[$index]->{$rel} eq "HASH";
2185 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2186 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2187 my $related = $result->result_source->_resolve_condition(
2188 $reverse_relinfo->{cond},
2194 delete $data->[$index]->{$rel};
2195 $data->[$index] = {%{$data->[$index]}, %$related};
2197 push @columns, keys %$related if $index == 0;
2201 ## inherit the data locked in the conditions of the resultset
2202 my ($rs_data) = $self->_merge_with_rscond({});
2203 delete @{$rs_data}{@columns};
2205 ## do bulk insert on current row
2206 $rsrc->storage->insert_bulk(
2208 [@columns, keys %$rs_data],
2209 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2212 ## do the has_many relationships
2213 foreach my $item (@$data) {
2217 foreach my $rel (@rels) {
2218 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2220 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2222 my $child = $main_row->$rel;
2224 my $related = $child->result_source->_resolve_condition(
2225 $rels->{$rel}{cond},
2231 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2232 my @populate = map { {%$_, %$related} } @rows_to_add;
2234 $child->populate( \@populate );
2241 # populate() argumnets went over several incarnations
2242 # What we ultimately support is AoH
2243 sub _normalize_populate_args {
2244 my ($self, $arg) = @_;
2246 if (ref $arg eq 'ARRAY') {
2250 elsif (ref $arg->[0] eq 'HASH') {
2253 elsif (ref $arg->[0] eq 'ARRAY') {
2255 my @colnames = @{$arg->[0]};
2256 foreach my $values (@{$arg}[1 .. $#$arg]) {
2257 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2263 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2270 =item Arguments: none
2272 =item Return Value: L<$pager|Data::Page>
2276 Returns a L<Data::Page> object for the current resultset. Only makes
2277 sense for queries with a C<page> attribute.
2279 To get the full count of entries for a paged resultset, call
2280 C<total_entries> on the L<Data::Page> object.
2287 return $self->{pager} if $self->{pager};
2289 my $attrs = $self->{attrs};
2290 if (!defined $attrs->{page}) {
2291 $self->throw_exception("Can't create pager for non-paged rs");
2293 elsif ($attrs->{page} <= 0) {
2294 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2296 $attrs->{rows} ||= 10;
2298 # throw away the paging flags and re-run the count (possibly
2299 # with a subselect) to get the real total count
2300 my $count_attrs = { %$attrs };
2301 delete @{$count_attrs}{qw/rows offset page pager/};
2303 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2305 require DBIx::Class::ResultSet::Pager;
2306 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2307 sub { $total_rs->count }, #lazy-get the total
2309 $self->{attrs}{page},
2317 =item Arguments: $page_number
2319 =item Return Value: L<$resultset|/search>
2323 Returns a resultset for the $page_number page of the resultset on which page
2324 is called, where each page contains a number of rows equal to the 'rows'
2325 attribute set on the resultset (10 by default).
2330 my ($self, $page) = @_;
2331 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2338 =item Arguments: \%col_data
2340 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2344 Creates a new result object in the resultset's result class and returns
2345 it. The row is not inserted into the database at this point, call
2346 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2347 will tell you whether the result object has been inserted or not.
2349 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2354 my ($self, $values) = @_;
2356 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2359 $self->throw_exception( "new_result expects a hashref" )
2360 unless (ref $values eq 'HASH');
2362 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2366 @$cols_from_relations
2367 ? (-cols_from_relations => $cols_from_relations)
2369 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2372 return $self->result_class->new(\%new);
2375 # _merge_with_rscond
2377 # Takes a simple hash of K/V data and returns its copy merged with the
2378 # condition already present on the resultset. Additionally returns an
2379 # arrayref of value/condition names, which were inferred from related
2380 # objects (this is needed for in-memory related objects)
2381 sub _merge_with_rscond {
2382 my ($self, $data) = @_;
2384 my (%new_data, @cols_from_relations);
2386 my $alias = $self->{attrs}{alias};
2388 if (! defined $self->{cond}) {
2389 # just massage $data below
2391 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2392 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2393 @cols_from_relations = keys %new_data;
2395 elsif (ref $self->{cond} ne 'HASH') {
2396 $self->throw_exception(
2397 "Can't abstract implicit construct, resultset condition not a hash"
2401 # precendence must be given to passed values over values inherited from
2402 # the cond, so the order here is important.
2403 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2404 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2406 while ( my($col, $value) = each %implied ) {
2407 my $vref = ref $value;
2413 (keys %$value)[0] eq '='
2415 $new_data{$col} = $value->{'='};
2417 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2418 $new_data{$col} = $value;
2425 %{ $self->_remove_alias($data, $alias) },
2428 return (\%new_data, \@cols_from_relations);
2431 # _has_resolved_attr
2433 # determines if the resultset defines at least one
2434 # of the attributes supplied
2436 # used to determine if a subquery is neccessary
2438 # supports some virtual attributes:
2440 # This will scan for any joins being present on the resultset.
2441 # It is not a mere key-search but a deep inspection of {from}
2444 sub _has_resolved_attr {
2445 my ($self, @attr_names) = @_;
2447 my $attrs = $self->_resolved_attrs;
2451 for my $n (@attr_names) {
2452 if (grep { $n eq $_ } (qw/-join/) ) {
2453 $extra_checks{$n}++;
2457 my $attr = $attrs->{$n};
2459 next if not defined $attr;
2461 if (ref $attr eq 'HASH') {
2462 return 1 if keys %$attr;
2464 elsif (ref $attr eq 'ARRAY') {
2472 # a resolved join is expressed as a multi-level from
2474 $extra_checks{-join}
2476 ref $attrs->{from} eq 'ARRAY'
2478 @{$attrs->{from}} > 1
2486 # Recursively collapse the condition.
2488 sub _collapse_cond {
2489 my ($self, $cond, $collapsed) = @_;
2493 if (ref $cond eq 'ARRAY') {
2494 foreach my $subcond (@$cond) {
2495 next unless ref $subcond; # -or
2496 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2499 elsif (ref $cond eq 'HASH') {
2500 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2501 foreach my $subcond (@{$cond->{-and}}) {
2502 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2506 foreach my $col (keys %$cond) {
2507 my $value = $cond->{$col};
2508 $collapsed->{$col} = $value;
2518 # Remove the specified alias from the specified query hash. A copy is made so
2519 # the original query is not modified.
2522 my ($self, $query, $alias) = @_;
2524 my %orig = %{ $query || {} };
2527 foreach my $key (keys %orig) {
2529 $unaliased{$key} = $orig{$key};
2532 $unaliased{$1} = $orig{$key}
2533 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2543 =item Arguments: none
2545 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2549 Returns the SQL query and bind vars associated with the invocant.
2551 This is generally used as the RHS for a subquery.
2558 my $attrs = { %{ $self->_resolved_attrs } };
2563 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2564 # $sql also has no wrapping parenthesis in list ctx
2566 my $sqlbind = $self->result_source->storage
2567 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2576 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2578 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2582 my $artist = $schema->resultset('Artist')->find_or_new(
2583 { artist => 'fred' }, { key => 'artists' });
2585 $cd->cd_to_producer->find_or_new({ producer => $producer },
2586 { key => 'primary });
2588 Find an existing record from this resultset using L</find>. if none exists,
2589 instantiate a new result object and return it. The object will not be saved
2590 into your storage until you call L<DBIx::Class::Row/insert> on it.
2592 You most likely want this method when looking for existing rows using a unique
2593 constraint that is not the primary key, or looking for related rows.
2595 If you want objects to be saved immediately, use L</find_or_create> instead.
2597 B<Note>: Make sure to read the documentation of L</find> and understand the
2598 significance of the C<key> attribute, as its lack may skew your search, and
2599 subsequently result in spurious new objects.
2601 B<Note>: Take care when using C<find_or_new> with a table having
2602 columns with default values that you intend to be automatically
2603 supplied by the database (e.g. an auto_increment primary key column).
2604 In normal usage, the value of such columns should NOT be included at
2605 all in the call to C<find_or_new>, even when set to C<undef>.
2611 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2612 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2613 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2616 return $self->new_result($hash);
2623 =item Arguments: \%col_data
2625 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2629 Attempt to create a single new row or a row with multiple related rows
2630 in the table represented by the resultset (and related tables). This
2631 will not check for duplicate rows before inserting, use
2632 L</find_or_create> to do that.
2634 To create one row for this resultset, pass a hashref of key/value
2635 pairs representing the columns of the table and the values you wish to
2636 store. If the appropriate relationships are set up, foreign key fields
2637 can also be passed an object representing the foreign row, and the
2638 value will be set to its primary key.
2640 To create related objects, pass a hashref of related-object column values
2641 B<keyed on the relationship name>. If the relationship is of type C<multi>
2642 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2643 The process will correctly identify columns holding foreign keys, and will
2644 transparently populate them from the keys of the corresponding relation.
2645 This can be applied recursively, and will work correctly for a structure
2646 with an arbitrary depth and width, as long as the relationships actually
2647 exists and the correct column data has been supplied.
2649 Instead of hashrefs of plain related data (key/value pairs), you may
2650 also pass new or inserted objects. New objects (not inserted yet, see
2651 L</new_result>), will be inserted into their appropriate tables.
2653 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2655 Example of creating a new row.
2657 $person_rs->create({
2658 name=>"Some Person",
2659 email=>"somebody@someplace.com"
2662 Example of creating a new row and also creating rows in a related C<has_many>
2663 or C<has_one> resultset. Note Arrayref.
2666 { artistid => 4, name => 'Manufactured Crap', cds => [
2667 { title => 'My First CD', year => 2006 },
2668 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2673 Example of creating a new row and also creating a row in a related
2674 C<belongs_to> resultset. Note Hashref.
2677 title=>"Music for Silly Walks",
2680 name=>"Silly Musician",
2688 When subclassing ResultSet never attempt to override this method. Since
2689 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2690 lot of the internals simply never call it, so your override will be
2691 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2692 or L<DBIx::Class::Row/insert> depending on how early in the
2693 L</create> process you need to intervene. See also warning pertaining to
2701 my ($self, $attrs) = @_;
2702 $self->throw_exception( "create needs a hashref" )
2703 unless ref $attrs eq 'HASH';
2704 return $self->new_result($attrs)->insert;
2707 =head2 find_or_create
2711 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2713 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2717 $cd->cd_to_producer->find_or_create({ producer => $producer },
2718 { key => 'primary' });
2720 Tries to find a record based on its primary key or unique constraints; if none
2721 is found, creates one and returns that instead.
2723 my $cd = $schema->resultset('CD')->find_or_create({
2725 artist => 'Massive Attack',
2726 title => 'Mezzanine',
2730 Also takes an optional C<key> attribute, to search by a specific key or unique
2731 constraint. For example:
2733 my $cd = $schema->resultset('CD')->find_or_create(
2735 artist => 'Massive Attack',
2736 title => 'Mezzanine',
2738 { key => 'cd_artist_title' }
2741 B<Note>: Make sure to read the documentation of L</find> and understand the
2742 significance of the C<key> attribute, as its lack may skew your search, and
2743 subsequently result in spurious row creation.
2745 B<Note>: Because find_or_create() reads from the database and then
2746 possibly inserts based on the result, this method is subject to a race
2747 condition. Another process could create a record in the table after
2748 the find has completed and before the create has started. To avoid
2749 this problem, use find_or_create() inside a transaction.
2751 B<Note>: Take care when using C<find_or_create> with a table having
2752 columns with default values that you intend to be automatically
2753 supplied by the database (e.g. an auto_increment primary key column).
2754 In normal usage, the value of such columns should NOT be included at
2755 all in the call to C<find_or_create>, even when set to C<undef>.
2757 See also L</find> and L</update_or_create>. For information on how to declare
2758 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2760 If you need to know if an existing row was found or a new one created use
2761 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2762 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2765 my $cd = $schema->resultset('CD')->find_or_new({
2767 artist => 'Massive Attack',
2768 title => 'Mezzanine',
2772 if( !$cd->in_storage ) {
2779 sub find_or_create {
2781 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2782 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2783 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2786 return $self->create($hash);
2789 =head2 update_or_create
2793 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2795 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2799 $resultset->update_or_create({ col => $val, ... });
2801 Like L</find_or_create>, but if a row is found it is immediately updated via
2802 C<< $found_row->update (\%col_data) >>.
2805 Takes an optional C<key> attribute to search on a specific unique constraint.
2808 # In your application
2809 my $cd = $schema->resultset('CD')->update_or_create(
2811 artist => 'Massive Attack',
2812 title => 'Mezzanine',
2815 { key => 'cd_artist_title' }
2818 $cd->cd_to_producer->update_or_create({
2819 producer => $producer,
2825 B<Note>: Make sure to read the documentation of L</find> and understand the
2826 significance of the C<key> attribute, as its lack may skew your search, and
2827 subsequently result in spurious row creation.
2829 B<Note>: Take care when using C<update_or_create> with a table having
2830 columns with default values that you intend to be automatically
2831 supplied by the database (e.g. an auto_increment primary key column).
2832 In normal usage, the value of such columns should NOT be included at
2833 all in the call to C<update_or_create>, even when set to C<undef>.
2835 See also L</find> and L</find_or_create>. For information on how to declare
2836 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2838 If you need to know if an existing row was updated or a new one created use
2839 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2840 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2845 sub update_or_create {
2847 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2848 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2850 my $row = $self->find($cond, $attrs);
2852 $row->update($cond);
2856 return $self->create($cond);
2859 =head2 update_or_new
2863 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2865 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2869 $resultset->update_or_new({ col => $val, ... });
2871 Like L</find_or_new> but if a row is found it is immediately updated via
2872 C<< $found_row->update (\%col_data) >>.
2876 # In your application
2877 my $cd = $schema->resultset('CD')->update_or_new(
2879 artist => 'Massive Attack',
2880 title => 'Mezzanine',
2883 { key => 'cd_artist_title' }
2886 if ($cd->in_storage) {
2887 # the cd was updated
2890 # the cd is not yet in the database, let's insert it
2894 B<Note>: Make sure to read the documentation of L</find> and understand the
2895 significance of the C<key> attribute, as its lack may skew your search, and
2896 subsequently result in spurious new objects.
2898 B<Note>: Take care when using C<update_or_new> with a table having
2899 columns with default values that you intend to be automatically
2900 supplied by the database (e.g. an auto_increment primary key column).
2901 In normal usage, the value of such columns should NOT be included at
2902 all in the call to C<update_or_new>, even when set to C<undef>.
2904 See also L</find>, L</find_or_create> and L</find_or_new>.
2910 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2911 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2913 my $row = $self->find( $cond, $attrs );
2914 if ( defined $row ) {
2915 $row->update($cond);
2919 return $self->new_result($cond);
2926 =item Arguments: none
2928 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2932 Gets the contents of the cache for the resultset, if the cache is set.
2934 The cache is populated either by using the L</prefetch> attribute to
2935 L</search> or by calling L</set_cache>.
2947 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2949 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2953 Sets the contents of the cache for the resultset. Expects an arrayref
2954 of objects of the same class as those produced by the resultset. Note that
2955 if the cache is set, the resultset will return the cached objects rather
2956 than re-querying the database even if the cache attr is not set.
2958 The contents of the cache can also be populated by using the
2959 L</prefetch> attribute to L</search>.
2964 my ( $self, $data ) = @_;
2965 $self->throw_exception("set_cache requires an arrayref")
2966 if defined($data) && (ref $data ne 'ARRAY');
2967 $self->{all_cache} = $data;
2974 =item Arguments: none
2976 =item Return Value: undef
2980 Clears the cache for the resultset.
2985 shift->set_cache(undef);
2992 =item Arguments: none
2994 =item Return Value: true, if the resultset has been paginated
3002 return !!$self->{attrs}{page};
3009 =item Arguments: none
3011 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3019 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3022 =head2 related_resultset
3026 =item Arguments: $rel_name
3028 =item Return Value: L<$resultset|/search>
3032 Returns a related resultset for the supplied relationship name.
3034 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3038 sub related_resultset {
3039 my ($self, $rel) = @_;
3041 return $self->{related_resultsets}{$rel} ||= do {
3042 my $rsrc = $self->result_source;
3043 my $rel_info = $rsrc->relationship_info($rel);
3045 $self->throw_exception(
3046 "search_related: result source '" . $rsrc->source_name .
3047 "' has no such relationship $rel")
3050 my $attrs = $self->_chain_relationship($rel);
3052 my $join_count = $attrs->{seen_join}{$rel};
3054 my $alias = $self->result_source->storage
3055 ->relname_to_table_alias($rel, $join_count);
3057 # since this is search_related, and we already slid the select window inwards
3058 # (the select/as attrs were deleted in the beginning), we need to flip all
3059 # left joins to inner, so we get the expected results
3060 # read the comment on top of the actual function to see what this does
3061 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3064 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3065 delete @{$attrs}{qw(result_class alias)};
3069 if (my $cache = $self->get_cache) {
3070 $related_cache = [ map
3071 { @{$_->related_resultset($rel)->get_cache||[]} }
3076 my $rel_source = $rsrc->related_source($rel);
3080 # The reason we do this now instead of passing the alias to the
3081 # search_rs below is that if you wrap/overload resultset on the
3082 # source you need to know what alias it's -going- to have for things
3083 # to work sanely (e.g. RestrictWithObject wants to be able to add
3084 # extra query restrictions, and these may need to be $alias.)
3086 my $rel_attrs = $rel_source->resultset_attributes;
3087 local $rel_attrs->{alias} = $alias;
3089 $rel_source->resultset
3093 where => $attrs->{where},
3096 $new->set_cache($related_cache) if $related_cache;
3101 =head2 current_source_alias
3105 =item Arguments: none
3107 =item Return Value: $source_alias
3111 Returns the current table alias for the result source this resultset is built
3112 on, that will be used in the SQL query. Usually it is C<me>.
3114 Currently the source alias that refers to the result set returned by a
3115 L</search>/L</find> family method depends on how you got to the resultset: it's
3116 C<me> by default, but eg. L</search_related> aliases it to the related result
3117 source name (and keeps C<me> referring to the original result set). The long
3118 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3119 (and make this method unnecessary).
3121 Thus it's currently necessary to use this method in predefined queries (see
3122 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3123 source alias of the current result set:
3125 # in a result set class
3127 my ($self, $user) = @_;
3129 my $me = $self->current_source_alias;
3131 return $self->search({
3132 "$me.modified" => $user->id,
3138 sub current_source_alias {
3139 return (shift->{attrs} || {})->{alias} || 'me';
3142 =head2 as_subselect_rs
3146 =item Arguments: none
3148 =item Return Value: L<$resultset|/search>
3152 Act as a barrier to SQL symbols. The resultset provided will be made into a
3153 "virtual view" by including it as a subquery within the from clause. From this
3154 point on, any joined tables are inaccessible to ->search on the resultset (as if
3155 it were simply where-filtered without joins). For example:
3157 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3159 # 'x' now pollutes the query namespace
3161 # So the following works as expected
3162 my $ok_rs = $rs->search({'x.other' => 1});
3164 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3165 # def) we look for one row with contradictory terms and join in another table
3166 # (aliased 'x_2') which we never use
3167 my $broken_rs = $rs->search({'x.name' => 'def'});
3169 my $rs2 = $rs->as_subselect_rs;
3171 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3172 my $not_joined_rs = $rs2->search({'x.other' => 1});
3174 # works as expected: finds a 'table' row related to two x rows (abc and def)
3175 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3177 Another example of when one might use this would be to select a subset of
3178 columns in a group by clause:
3180 my $rs = $schema->resultset('Bar')->search(undef, {
3181 group_by => [qw{ id foo_id baz_id }],
3182 })->as_subselect_rs->search(undef, {
3183 columns => [qw{ id foo_id }]
3186 In the above example normally columns would have to be equal to the group by,
3187 but because we isolated the group by into a subselect the above works.
3191 sub as_subselect_rs {
3194 my $attrs = $self->_resolved_attrs;
3196 my $fresh_rs = (ref $self)->new (
3197 $self->result_source
3200 # these pieces will be locked in the subquery
3201 delete $fresh_rs->{cond};
3202 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3204 return $fresh_rs->search( {}, {
3206 $attrs->{alias} => $self->as_query,
3207 -alias => $attrs->{alias},
3208 -rsrc => $self->result_source,
3210 alias => $attrs->{alias},
3214 # This code is called by search_related, and makes sure there
3215 # is clear separation between the joins before, during, and
3216 # after the relationship. This information is needed later
3217 # in order to properly resolve prefetch aliases (any alias
3218 # with a relation_chain_depth less than the depth of the
3219 # current prefetch is not considered)
3221 # The increments happen twice per join. An even number means a
3222 # relationship specified via a search_related, whereas an odd
3223 # number indicates a join/prefetch added via attributes
3225 # Also this code will wrap the current resultset (the one we
3226 # chain to) in a subselect IFF it contains limiting attributes
3227 sub _chain_relationship {
3228 my ($self, $rel) = @_;
3229 my $source = $self->result_source;
3230 my $attrs = { %{$self->{attrs}||{}} };
3232 # we need to take the prefetch the attrs into account before we
3233 # ->_resolve_join as otherwise they get lost - captainL
3234 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3236 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
3238 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3241 my @force_subq_attrs = qw/offset rows group_by having/;
3244 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3246 $self->_has_resolved_attr (@force_subq_attrs)
3248 # Nuke the prefetch (if any) before the new $rs attrs
3249 # are resolved (prefetch is useless - we are wrapping
3250 # a subquery anyway).
3251 my $rs_copy = $self->search;
3252 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3253 $rs_copy->{attrs}{join},
3254 delete $rs_copy->{attrs}{prefetch},
3259 -alias => $attrs->{alias},
3260 $attrs->{alias} => $rs_copy->as_query,
3262 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3263 $seen->{-relation_chain_depth} = 0;
3265 elsif ($attrs->{from}) { #shallow copy suffices
3266 $from = [ @{$attrs->{from}} ];
3271 -alias => $attrs->{alias},
3272 $attrs->{alias} => $source->from,
3276 my $jpath = ($seen->{-relation_chain_depth})
3277 ? $from->[-1][0]{-join_path}
3280 my @requested_joins = $source->_resolve_join(
3287 push @$from, @requested_joins;
3289 $seen->{-relation_chain_depth}++;
3291 # if $self already had a join/prefetch specified on it, the requested
3292 # $rel might very well be already included. What we do in this case
3293 # is effectively a no-op (except that we bump up the chain_depth on
3294 # the join in question so we could tell it *is* the search_related)
3297 # we consider the last one thus reverse
3298 for my $j (reverse @requested_joins) {
3299 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3300 if ($rel eq $last_j) {
3301 $j->[0]{-relation_chain_depth}++;
3307 unless ($already_joined) {
3308 push @$from, $source->_resolve_join(
3316 $seen->{-relation_chain_depth}++;
3318 return {%$attrs, from => $from, seen_join => $seen};
3321 # FIXME - this needs to go live in Schema with the tree walker... or
3323 my $inflatemap_checker;
3324 $inflatemap_checker = sub {
3325 my ($rsrc, $relpaths) = @_;
3330 $_ =~ /^ ( [^\.]+ ) \. (.+) $/x
3333 push @{$rels->{$1}}, $2;
3336 for my $rel (keys %$rels) {
3337 my $rel_rsrc = try {
3338 $rsrc->related_source ($rel)
3340 $rsrc->throw_exception(sprintf(
3341 "Inflation into non-existent relationship '%s' of '%s' requested, "
3342 . "check the inflation specification (columns/as) ending in '...%s.%s'",
3346 ( sort { length($a) <=> length ($b) } @{$rels->{$rel}} )[0],
3349 $inflatemap_checker->($rel_rsrc, $rels->{$rel});
3355 sub _resolved_attrs {
3357 return $self->{_attrs} if $self->{_attrs};
3359 my $attrs = { %{ $self->{attrs} || {} } };
3360 my $source = $self->result_source;
3361 my $alias = $attrs->{alias};
3363 # default selection list
3364 $attrs->{columns} = [ $source->columns ]
3365 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3367 # merge selectors together
3368 for (qw/columns select as/) {
3369 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3370 if $attrs->{$_} or $attrs->{"+$_"};
3373 # disassemble columns
3375 if (my $cols = delete $attrs->{columns}) {
3376 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3377 if (ref $c eq 'HASH') {
3378 for my $as (sort keys %$c) {
3379 push @sel, $c->{$as};
3390 # when trying to weed off duplicates later do not go past this point -
3391 # everything added from here on is unbalanced "anyone's guess" stuff
3392 my $dedup_stop_idx = $#as;
3394 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3396 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3397 if $attrs->{select};
3399 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3400 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3402 # disqualify all $alias.col as-bits (inflate-map mandated)
3403 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3405 # de-duplicate the result (remove *identical* select/as pairs)
3406 # and also die on duplicate {as} pointing to different {select}s
3407 # not using a c-style for as the condition is prone to shrinkage
3410 while ($i <= $dedup_stop_idx) {
3411 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3416 elsif ($seen->{$as[$i]}++) {
3417 $self->throw_exception(
3418 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3426 # validate the user-supplied 'as' chain
3427 # folks get too confused by the (logical) exception message, need to
3428 # go to some lengths to clarify the text
3430 # FIXME - this needs to go live in Schema with the tree walker... or
3432 $inflatemap_checker->($source, \@as);
3434 $attrs->{select} = \@sel;
3435 $attrs->{as} = \@as;
3437 $attrs->{from} ||= [{
3439 -alias => $self->{attrs}{alias},
3440 $self->{attrs}{alias} => $source->from,
3443 if ( $attrs->{join} || $attrs->{prefetch} ) {
3445 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3446 if ref $attrs->{from} ne 'ARRAY';
3448 my $join = (delete $attrs->{join}) || {};
3450 if ( defined $attrs->{prefetch} ) {
3451 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3454 $attrs->{from} = # have to copy here to avoid corrupting the original
3456 @{ $attrs->{from} },
3457 $source->_resolve_join(
3460 { %{ $attrs->{seen_join} || {} } },
3461 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3462 ? $attrs->{from}[-1][0]{-join_path}
3469 if ( defined $attrs->{order_by} ) {
3470 $attrs->{order_by} = (
3471 ref( $attrs->{order_by} ) eq 'ARRAY'
3472 ? [ @{ $attrs->{order_by} } ]
3473 : [ $attrs->{order_by} || () ]
3477 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3478 $attrs->{group_by} = [ $attrs->{group_by} ];
3481 # generate the distinct induced group_by early, as prefetch will be carried via a
3482 # subquery (since a group_by is present)
3483 if (delete $attrs->{distinct}) {
3484 if ($attrs->{group_by}) {
3485 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3488 # distinct affects only the main selection part, not what prefetch may
3490 $attrs->{group_by} = $source->storage->_group_over_selection (
3498 # generate selections based on the prefetch helper
3500 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3501 if defined $attrs->{prefetch};
3505 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3506 if $attrs->{_dark_selector};
3508 $attrs->{collapse} = 1;
3510 # this is a separate structure (we don't look in {from} directly)
3511 # as the resolver needs to shift things off the lists to work
3512 # properly (identical-prefetches on different branches)
3514 if (ref $attrs->{from} eq 'ARRAY') {
3516 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3518 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3519 next unless $j->[0]{-alias};
3520 next unless $j->[0]{-join_path};
3521 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3523 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3526 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3527 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3531 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3533 # we need to somehow mark which columns came from prefetch
3535 my $sel_end = $#{$attrs->{select}};
3536 $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
3539 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3540 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3543 if ( ! List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3544 $attrs->{_single_resultclass_inflation} = 1;
3545 $attrs->{collapse} = 0;
3548 # run through the resulting joinstructure (starting from our current slot)
3549 # and unset collapse if proven unnesessary
3551 # also while we are at it find out if the current root source has
3552 # been premultiplied by previous related_source chaining
3554 # this allows to predict whether a root object with all other relation
3555 # data set to NULL is in fact unique
3556 if ($attrs->{collapse}) {
3558 if (ref $attrs->{from} eq 'ARRAY') {
3560 if (@{$attrs->{from}} <= 1) {
3561 # no joins - no collapse
3562 $attrs->{collapse} = 0;
3565 # find where our table-spec starts
3566 my @fromlist = @{$attrs->{from}};
3568 my $t = shift @fromlist;
3571 # me vs join from-spec distinction - a ref means non-root
3572 if (ref $t eq 'ARRAY') {
3574 $is_multi ||= ! $t->{-is_single};
3576 last if ($t->{-alias} && $t->{-alias} eq $alias);
3577 $attrs->{_main_source_premultiplied} ||= $is_multi;
3580 # no non-singles remaining, nor any premultiplication - nothing to collapse
3582 ! $attrs->{_main_source_premultiplied}
3584 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3586 $attrs->{collapse} = 0;
3592 # if we can not analyze the from - err on the side of safety
3593 $attrs->{_main_source_premultiplied} = 1;
3597 # if both page and offset are specified, produce a combined offset
3598 # even though it doesn't make much sense, this is what pre 081xx has
3600 if (my $page = delete $attrs->{page}) {
3602 ($attrs->{rows} * ($page - 1))
3604 ($attrs->{offset} || 0)
3608 return $self->{_attrs} = $attrs;
3612 my ($self, $attr) = @_;
3614 if (ref $attr eq 'HASH') {
3615 return $self->_rollout_hash($attr);
3616 } elsif (ref $attr eq 'ARRAY') {
3617 return $self->_rollout_array($attr);
3623 sub _rollout_array {
3624 my ($self, $attr) = @_;
3627 foreach my $element (@{$attr}) {
3628 if (ref $element eq 'HASH') {
3629 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3630 } elsif (ref $element eq 'ARRAY') {
3631 # XXX - should probably recurse here
3632 push( @rolled_array, @{$self->_rollout_array($element)} );
3634 push( @rolled_array, $element );
3637 return \@rolled_array;
3641 my ($self, $attr) = @_;
3644 foreach my $key (keys %{$attr}) {
3645 push( @rolled_array, { $key => $attr->{$key} } );
3647 return \@rolled_array;
3650 sub _calculate_score {
3651 my ($self, $a, $b) = @_;
3653 if (defined $a xor defined $b) {
3656 elsif (not defined $a) {
3660 if (ref $b eq 'HASH') {
3661 my ($b_key) = keys %{$b};
3662 if (ref $a eq 'HASH') {
3663 my ($a_key) = keys %{$a};
3664 if ($a_key eq $b_key) {
3665 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3670 return ($a eq $b_key) ? 1 : 0;
3673 if (ref $a eq 'HASH') {
3674 my ($a_key) = keys %{$a};
3675 return ($b eq $a_key) ? 1 : 0;
3677 return ($b eq $a) ? 1 : 0;
3682 sub _merge_joinpref_attr {
3683 my ($self, $orig, $import) = @_;
3685 return $import unless defined($orig);
3686 return $orig unless defined($import);
3688 $orig = $self->_rollout_attr($orig);
3689 $import = $self->_rollout_attr($import);
3692 foreach my $import_element ( @{$import} ) {
3693 # find best candidate from $orig to merge $b_element into
3694 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3695 foreach my $orig_element ( @{$orig} ) {
3696 my $score = $self->_calculate_score( $orig_element, $import_element );
3697 if ($score > $best_candidate->{score}) {
3698 $best_candidate->{position} = $position;
3699 $best_candidate->{score} = $score;
3703 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3704 $import_key = '' if not defined $import_key;
3706 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3707 push( @{$orig}, $import_element );
3709 my $orig_best = $orig->[$best_candidate->{position}];
3710 # merge orig_best and b_element together and replace original with merged
3711 if (ref $orig_best ne 'HASH') {
3712 $orig->[$best_candidate->{position}] = $import_element;
3713 } elsif (ref $import_element eq 'HASH') {
3714 my ($key) = keys %{$orig_best};
3715 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3718 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3721 return @$orig ? $orig : ();
3729 require Hash::Merge;
3730 my $hm = Hash::Merge->new;
3732 $hm->specify_behavior({
3735 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3737 if ($defl xor $defr) {
3738 return [ $defl ? $_[0] : $_[1] ];
3743 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3747 return [$_[0], $_[1]];
3751 return $_[1] if !defined $_[0];
3752 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3753 return [$_[0], @{$_[1]}]
3756 return [] if !defined $_[0] and !keys %{$_[1]};
3757 return [ $_[1] ] if !defined $_[0];
3758 return [ $_[0] ] if !keys %{$_[1]};
3759 return [$_[0], $_[1]]
3764 return $_[0] if !defined $_[1];
3765 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3766 return [@{$_[0]}, $_[1]]
3769 my @ret = @{$_[0]} or return $_[1];
3770 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3771 my %idx = map { $_ => 1 } @ret;
3772 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3776 return [ $_[1] ] if ! @{$_[0]};
3777 return $_[0] if !keys %{$_[1]};
3778 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3779 return [ @{$_[0]}, $_[1] ];
3784 return [] if !keys %{$_[0]} and !defined $_[1];
3785 return [ $_[0] ] if !defined $_[1];
3786 return [ $_[1] ] if !keys %{$_[0]};
3787 return [$_[0], $_[1]]
3790 return [] if !keys %{$_[0]} and !@{$_[1]};
3791 return [ $_[0] ] if !@{$_[1]};
3792 return $_[1] if !keys %{$_[0]};
3793 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3794 return [ $_[0], @{$_[1]} ];
3797 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3798 return [ $_[0] ] if !keys %{$_[1]};
3799 return [ $_[1] ] if !keys %{$_[0]};
3800 return [ $_[0] ] if $_[0] eq $_[1];
3801 return [ $_[0], $_[1] ];
3804 } => 'DBIC_RS_ATTR_MERGER');
3808 return $hm->merge ($_[1], $_[2]);
3812 sub STORABLE_freeze {
3813 my ($self, $cloning) = @_;
3814 my $to_serialize = { %$self };
3816 # A cursor in progress can't be serialized (and would make little sense anyway)
3817 # the parser can be regenerated (and can't be serialized)
3818 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3820 # nor is it sensical to store a not-yet-fired-count pager
3821 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3822 delete $to_serialize->{pager};
3825 Storable::nfreeze($to_serialize);
3828 # need this hook for symmetry
3830 my ($self, $cloning, $serialized) = @_;
3832 %$self = %{ Storable::thaw($serialized) };
3838 =head2 throw_exception
3840 See L<DBIx::Class::Schema/throw_exception> for details.
3844 sub throw_exception {
3847 if (ref $self and my $rsrc = $self->result_source) {
3848 $rsrc->throw_exception(@_)
3851 DBIx::Class::Exception->throw(@_);
3859 # XXX: FIXME: Attributes docs need clearing up
3863 Attributes are used to refine a ResultSet in various ways when
3864 searching for data. They can be passed to any method which takes an
3865 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3868 Default attributes can be set on the result class using
3869 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3870 the CAVEATS on that feature before using it!)
3872 These are in no particular order:
3878 =item Value: ( $order_by | \@order_by | \%order_by )
3882 Which column(s) to order the results by.
3884 [The full list of suitable values is documented in
3885 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3888 If a single column name, or an arrayref of names is supplied, the
3889 argument is passed through directly to SQL. The hashref syntax allows
3890 for connection-agnostic specification of ordering direction:
3892 For descending order:
3894 order_by => { -desc => [qw/col1 col2 col3/] }
3896 For explicit ascending order:
3898 order_by => { -asc => 'col' }
3900 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3901 supported, although you are strongly encouraged to use the hashref
3902 syntax as outlined above.
3908 =item Value: \@columns | \%columns | $column
3912 Shortcut to request a particular set of columns to be retrieved. Each
3913 column spec may be a string (a table column name), or a hash (in which
3914 case the key is the C<as> value, and the value is used as the C<select>
3915 expression). Adds C<me.> onto the start of any column without a C<.> in
3916 it and sets C<select> from that, then auto-populates C<as> from
3917 C<select> as normal. (You may also use the C<cols> attribute, as in
3918 earlier versions of DBIC.)
3920 Essentially C<columns> does the same as L</select> and L</as>.
3922 columns => [ 'foo', { bar => 'baz' } ]
3926 select => [qw/foo baz/],
3933 =item Value: \@columns
3937 Indicates additional columns to be selected from storage. Works the same
3938 as L</columns> but adds columns to the selection. (You may also use the
3939 C<include_columns> attribute, as in earlier versions of DBIC). For
3942 $schema->resultset('CD')->search(undef, {
3943 '+columns' => ['artist.name'],
3947 would return all CDs and include a 'name' column to the information
3948 passed to object inflation. Note that the 'artist' is the name of the
3949 column (or relationship) accessor, and 'name' is the name of the column
3950 accessor in the related table.
3952 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3953 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3954 unary plus operator before it.
3956 =head2 include_columns
3960 =item Value: \@columns
3964 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3970 =item Value: \@select_columns
3974 Indicates which columns should be selected from the storage. You can use
3975 column names, or in the case of RDBMS back ends, function or stored procedure
3978 $rs = $schema->resultset('Employee')->search(undef, {
3981 { count => 'employeeid' },
3982 { max => { length => 'name' }, -as => 'longest_name' }
3987 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3989 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3990 use L</select>, to instruct DBIx::Class how to store the result of the column.
3991 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3992 identifier aliasing. You can however alias a function, so you can use it in
3993 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3994 attribute> supplied as shown in the example above.
3996 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3997 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3998 unary plus operator before it.
4004 Indicates additional columns to be selected from storage. Works the same as
4005 L</select> but adds columns to the default selection, instead of specifying
4014 =item Value: \@inflation_names
4018 Indicates column names for object inflation. That is L</as> indicates the
4019 slot name in which the column value will be stored within the
4020 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4021 identifier by the C<get_column> method (or via the object accessor B<if one
4022 with the same name already exists>) as shown below. The L</as> attribute has
4023 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4025 $rs = $schema->resultset('Employee')->search(undef, {
4028 { count => 'employeeid' },
4029 { max => { length => 'name' }, -as => 'longest_name' }
4038 If the object against which the search is performed already has an accessor
4039 matching a column name specified in C<as>, the value can be retrieved using
4040 the accessor as normal:
4042 my $name = $employee->name();
4044 If on the other hand an accessor does not exist in the object, you need to
4045 use C<get_column> instead:
4047 my $employee_count = $employee->get_column('employee_count');
4049 You can create your own accessors if required - see
4050 L<DBIx::Class::Manual::Cookbook> for details.
4056 Indicates additional column names for those added via L</+select>. See L</as>.
4064 =item Value: ($rel_name | \@rel_names | \%rel_names)
4068 Contains a list of relationships that should be joined for this query. For
4071 # Get CDs by Nine Inch Nails
4072 my $rs = $schema->resultset('CD')->search(
4073 { 'artist.name' => 'Nine Inch Nails' },
4074 { join => 'artist' }
4077 Can also contain a hash reference to refer to the other relation's relations.
4080 package MyApp::Schema::Track;
4081 use base qw/DBIx::Class/;
4082 __PACKAGE__->table('track');
4083 __PACKAGE__->add_columns(qw/trackid cd position title/);
4084 __PACKAGE__->set_primary_key('trackid');
4085 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4088 # In your application
4089 my $rs = $schema->resultset('Artist')->search(
4090 { 'track.title' => 'Teardrop' },
4092 join => { cd => 'track' },
4093 order_by => 'artist.name',
4097 You need to use the relationship (not the table) name in conditions,
4098 because they are aliased as such. The current table is aliased as "me", so
4099 you need to use me.column_name in order to avoid ambiguity. For example:
4101 # Get CDs from 1984 with a 'Foo' track
4102 my $rs = $schema->resultset('CD')->search(
4105 'tracks.name' => 'Foo'
4107 { join => 'tracks' }
4110 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4111 similarly for a third time). For e.g.
4113 my $rs = $schema->resultset('Artist')->search({
4114 'cds.title' => 'Down to Earth',
4115 'cds_2.title' => 'Popular',
4117 join => [ qw/cds cds/ ],
4120 will return a set of all artists that have both a cd with title 'Down
4121 to Earth' and a cd with title 'Popular'.
4123 If you want to fetch related objects from other tables as well, see L</prefetch>
4126 NOTE: An internal join-chain pruner will discard certain joins while
4127 constructing the actual SQL query, as long as the joins in question do not
4128 affect the retrieved result. This for example includes 1:1 left joins
4129 that are not part of the restriction specification (WHERE/HAVING) nor are
4130 a part of the query selection.
4132 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4138 =item Value: (0 | 1)
4142 When set to a true value, indicates that any rows fetched from joined has_many
4143 relationships are to be aggregated into the corresponding "parent" object. For
4144 example, the resultset:
4146 my $rs = $schema->resultset('CD')->search({}, {
4147 '+columns' => [ qw/ tracks.title tracks.position / ],
4152 While executing the following query:
4154 SELECT me.*, tracks.title, tracks.position
4156 LEFT JOIN track tracks
4157 ON tracks.cdid = me.cdid
4159 Will return only as many objects as there are rows in the CD source, even
4160 though the result of the query may span many rows. Each of these CD objects
4161 will in turn have multiple "Track" objects hidden behind the has_many
4162 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4163 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4164 product"), with each CD object containing exactly one of all fetched Track data.
4166 When a collapse is requested on a non-ordered resultset, an order by some
4167 unique part of the main source (the left-most table) is inserted automatically.
4168 This is done so that the resultset is allowed to be "lazy" - calling
4169 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4170 object with all of its related data.
4172 If an L</order_by> is already declared, and orders the resultset in a way that
4173 makes collapsing as described above impossible (e.g. C<< ORDER BY
4174 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4175 switch to "eager" mode and slurp the entire resultset before consturcting the
4176 first object returned by L</next>.
4178 Setting this attribute on a resultset that does not join any has_many
4179 relations is a no-op.
4181 For a more in-depth discussion, see L</PREFETCHING>.
4187 =item Value: ($rel_name | \@rel_names | \%rel_names)
4191 This attribute is a shorthand for specifying a L</join> spec, adding all
4192 columns from the joined related sources as L</+columns> and setting
4193 L</collapse> to a true value. For example, the following two queries are
4196 my $rs = $schema->resultset('Artist')->search({}, {
4197 prefetch => { cds => ['genre', 'tracks' ] },
4202 my $rs = $schema->resultset('Artist')->search({}, {
4203 join => { cds => ['genre', 'tracks' ] },
4207 { +{ "cds.$_" => "cds.$_" } }
4208 $schema->source('Artist')->related_source('cds')->columns
4211 { +{ "cds.genre.$_" => "genre.$_" } }
4212 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4215 { +{ "cds.tracks.$_" => "tracks.$_" } }
4216 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4221 Both producing the following SQL:
4223 SELECT me.artistid, me.name, me.rank, me.charfield,
4224 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4225 genre.genreid, genre.name,
4226 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4229 ON cds.artist = me.artistid
4230 LEFT JOIN genre genre
4231 ON genre.genreid = cds.genreid
4232 LEFT JOIN track tracks
4233 ON tracks.cd = cds.cdid
4234 ORDER BY me.artistid
4236 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4237 the arguments are properly merged and generally do the right thing. For
4238 example, you may want to do the following:
4240 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4241 { 'genre.genreid' => undef },
4243 join => { cds => 'genre' },
4248 Which generates the following SQL:
4250 SELECT me.artistid, me.name, me.rank, me.charfield,
4251 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4254 ON cds.artist = me.artistid
4255 LEFT JOIN genre genre
4256 ON genre.genreid = cds.genreid
4257 WHERE genre.genreid IS NULL
4258 ORDER BY me.artistid
4260 For a more in-depth discussion, see L</PREFETCHING>.
4266 =item Value: $source_alias
4270 Sets the source alias for the query. Normally, this defaults to C<me>, but
4271 nested search queries (sub-SELECTs) might need specific aliases set to
4272 reference inner queries. For example:
4275 ->related_resultset('CDs')
4276 ->related_resultset('Tracks')
4278 'track.id' => { -ident => 'none_search.id' },
4282 my $ids = $self->search({
4285 alias => 'none_search',
4286 group_by => 'none_search.id',
4287 })->get_column('id')->as_query;
4289 $self->search({ id => { -in => $ids } })
4291 This attribute is directly tied to L</current_source_alias>.
4301 Makes the resultset paged and specifies the page to retrieve. Effectively
4302 identical to creating a non-pages resultset and then calling ->page($page)
4305 If L</rows> attribute is not specified it defaults to 10 rows per page.
4307 When you have a paged resultset, L</count> will only return the number
4308 of rows in the page. To get the total, use the L</pager> and call
4309 C<total_entries> on it.
4319 Specifies the maximum number of rows for direct retrieval or the number of
4320 rows per page if the page attribute or method is used.
4326 =item Value: $offset
4330 Specifies the (zero-based) row number for the first row to be returned, or the
4331 of the first row of the first page if paging is used.
4333 =head2 software_limit
4337 =item Value: (0 | 1)
4341 When combined with L</rows> and/or L</offset> the generated SQL will not
4342 include any limit dialect stanzas. Instead the entire result will be selected
4343 as if no limits were specified, and DBIC will perform the limit locally, by
4344 artificially advancing and finishing the resulting L</cursor>.
4346 This is the recommended way of performing resultset limiting when no sane RDBMS
4347 implementation is available (e.g.
4348 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4349 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4355 =item Value: \@columns
4359 A arrayref of columns to group by. Can include columns of joined tables.
4361 group_by => [qw/ column1 column2 ... /]
4367 =item Value: $condition
4371 HAVING is a select statement attribute that is applied between GROUP BY and
4372 ORDER BY. It is applied to the after the grouping calculations have been
4375 having => { 'count_employee' => { '>=', 100 } }
4377 or with an in-place function in which case literal SQL is required:
4379 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4385 =item Value: (0 | 1)
4389 Set to 1 to group by all columns. If the resultset already has a group_by
4390 attribute, this setting is ignored and an appropriate warning is issued.
4396 Adds to the WHERE clause.
4398 # only return rows WHERE deleted IS NULL for all searches
4399 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4401 Can be overridden by passing C<< { where => undef } >> as an attribute
4404 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4410 Set to 1 to cache search results. This prevents extra SQL queries if you
4411 revisit rows in your ResultSet:
4413 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4415 while( my $artist = $resultset->next ) {
4419 $rs->first; # without cache, this would issue a query
4421 By default, searches are not cached.
4423 For more examples of using these attributes, see
4424 L<DBIx::Class::Manual::Cookbook>.
4430 =item Value: ( 'update' | 'shared' | \$scalar )
4434 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4435 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4440 DBIx::Class supports arbitrary related data prefetching from multiple related
4441 sources. Any combination of relationship types and column sets are supported.
4442 If L<collapsing|/collapse> is requested, there is an additional requirement of
4443 selecting enough data to make every individual object uniquely identifiable.
4445 Here are some more involved examples, based on the following relationship map:
4448 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4449 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4450 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4452 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4454 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4458 my $rs = $schema->resultset('Tag')->search(
4467 The initial search results in SQL like the following:
4469 SELECT tag.*, cd.*, artist.* FROM tag
4470 JOIN cd ON tag.cd = cd.cdid
4471 JOIN artist ON cd.artist = artist.artistid
4473 L<DBIx::Class> has no need to go back to the database when we access the
4474 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4477 Simple prefetches will be joined automatically, so there is no need
4478 for a C<join> attribute in the above search.
4480 The L</prefetch> attribute can be used with any of the relationship types
4481 and multiple prefetches can be specified together. Below is a more complex
4482 example that prefetches a CD's artist, its liner notes (if present),
4483 the cover image, the tracks on that CD, and the guests on those
4486 my $rs = $schema->resultset('CD')->search(
4490 { artist => 'record_label'}, # belongs_to => belongs_to
4491 'liner_note', # might_have
4492 'cover_image', # has_one
4493 { tracks => 'guests' }, # has_many => has_many
4498 This will produce SQL like the following:
4500 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4504 ON artist.artistid = me.artistid
4505 JOIN record_label record_label
4506 ON record_label.labelid = artist.labelid
4507 LEFT JOIN track tracks
4508 ON tracks.cdid = me.cdid
4509 LEFT JOIN guest guests
4510 ON guests.trackid = track.trackid
4511 LEFT JOIN liner_notes liner_note
4512 ON liner_note.cdid = me.cdid
4513 JOIN cd_artwork cover_image
4514 ON cover_image.cdid = me.cdid
4517 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4518 C<tracks>, and C<guests> of the CD will all be available through the
4519 relationship accessors without the need for additional queries to the
4524 Prefetch does a lot of deep magic. As such, it may not behave exactly
4525 as you might expect.
4531 Prefetch uses the L</cache> to populate the prefetched relationships. This
4532 may or may not be what you want.
4536 If you specify a condition on a prefetched relationship, ONLY those
4537 rows that match the prefetched condition will be fetched into that relationship.
4538 This means that adding prefetch to a search() B<may alter> what is returned by
4539 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4541 my $artist_rs = $schema->resultset('Artist')->search({
4547 my $count = $artist_rs->first->cds->count;
4549 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4551 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4553 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4555 That cmp_ok() may or may not pass depending on the datasets involved. In other
4556 words the C<WHERE> condition would apply to the entire dataset, just like
4557 it would in regular SQL. If you want to add a condition only to the "right side"
4558 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4559 condition|DBIx::Class::Relationship::Base/condition>
4563 =head1 DBIC BIND VALUES
4565 Because DBIC may need more information to bind values than just the column name
4566 and value itself, it uses a special format for both passing and receiving bind
4567 values. Each bind value should be composed of an arrayref of
4568 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4574 If present (in any form), this is what is being passed directly to bind_param.
4575 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4576 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4578 If this is specified, all other bind options described below are ignored.
4582 If present, this is used to infer the actual bind attribute by passing to
4583 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4584 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4586 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4587 currently drivers are expected to "Do the Right Thing" when given a common
4588 datatype name. (Not ideal, but that's what we got at this point.)
4592 Currently used to correctly allocate buffers for bind_param_inout().
4593 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4594 or to a sensible value based on the "data_type".
4598 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4599 explicitly specified they are never overriden). Also used by some weird DBDs,
4600 where the column name should be available at bind_param time (e.g. Oracle).
4604 For backwards compatibility and convenience, the following shortcuts are
4607 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4608 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4609 [ undef, $val ] === [ {}, $val ]
4611 =head1 AUTHOR AND CONTRIBUTORS
4613 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4617 You may distribute this code under the same terms as Perl itself.