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 => $attrs->{_main_source_premultiplied},
1409 prune_null_branches => 1,
1410 }) )->($rows, @extra_collapser_args);
1412 # Regular multi-object
1415 # The rationale is - if this is the ::Row inflator itself, or an around()
1416 # we do prune, because we expect it.
1417 # If not the case - let the user deal with the full output themselves
1418 # Warn them while we are at it so we get a better idea what is out there
1420 $self->{_result_inflator}{prune_null_branches} = do {
1421 $res_class->isa('DBIx::Class::Row')
1422 } ? 1 : 0 unless defined $self->{_result_inflator}{prune_null_branches};
1424 unless ($self->{_result_inflator}{prune_null_branches}) {
1426 "ResultClass $res_class does not inherit from DBIx::Class::Row and "
1427 . 'therefore its inflate_result() will receive the full prefetched data '
1428 . 'tree, without any branch definedness checks. This is a compatibility '
1429 . 'measure which will eventually disappear entirely. Please refer to '
1430 . 't/resultset/inflate_result_api.t for an exhaustive description of the '
1431 . 'upcoming changes'
1435 ( $self->{_row_parser}{classic}{$self->{_result_inflator}{prune_null_branches}} ||= $rsrc->_mk_row_parser({
1437 inflate_map => $infmap,
1438 selection => $attrs->{select},
1439 collapse => $attrs->{collapse},
1440 premultiplied => $attrs->{_main_source_premultiplied},
1441 prune_null_branches => $self->{_result_inflator}{prune_null_branches},
1442 }) )->($rows, @extra_collapser_args);
1444 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1448 if ($attrs->{record_filter}) {
1449 $_ = $attrs->{record_filter}->($_) for @$rows;
1455 =head2 result_source
1459 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1461 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1465 An accessor for the primary ResultSource object from which this ResultSet
1472 =item Arguments: $result_class?
1474 =item Return Value: $result_class
1478 An accessor for the class to use when creating result objects. Defaults to
1479 C<< result_source->result_class >> - which in most cases is the name of the
1480 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1482 Note that changing the result_class will also remove any components
1483 that were originally loaded in the source class via
1484 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1485 in the original source class will not run.
1490 my ($self, $result_class) = @_;
1491 if ($result_class) {
1493 unless (ref $result_class) { # don't fire this for an object
1494 $self->ensure_class_loaded($result_class);
1496 $self->_result_class($result_class);
1497 # THIS LINE WOULD BE A BUG - this accessor specifically exists to
1498 # permit the user to set result class on one result set only; it only
1499 # chains if provided to search()
1500 #$self->{attrs}{result_class} = $result_class if ref $self;
1502 delete $self->{_result_inflator};
1504 $self->_result_class;
1511 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1513 =item Return Value: $count
1517 Performs an SQL C<COUNT> with the same query as the resultset was built
1518 with to find the number of elements. Passing arguments is equivalent to
1519 C<< $rs->search ($cond, \%attrs)->count >>
1525 return $self->search(@_)->count if @_ and defined $_[0];
1526 return scalar @{ $self->get_cache } if $self->get_cache;
1528 my $attrs = { %{ $self->_resolved_attrs } };
1530 # this is a little optimization - it is faster to do the limit
1531 # adjustments in software, instead of a subquery
1532 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1535 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1536 $crs = $self->_count_subq_rs ($attrs);
1539 $crs = $self->_count_rs ($attrs);
1541 my $count = $crs->next;
1543 $count -= $offset if $offset;
1544 $count = $rows if $rows and $rows < $count;
1545 $count = 0 if ($count < 0);
1554 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1556 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1560 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1561 This can be very handy for subqueries:
1563 ->search( { amount => $some_rs->count_rs->as_query } )
1565 As with regular resultsets the SQL query will be executed only after
1566 the resultset is accessed via L</next> or L</all>. That would return
1567 the same single value obtainable via L</count>.
1573 return $self->search(@_)->count_rs if @_;
1575 # this may look like a lack of abstraction (count() does about the same)
1576 # but in fact an _rs *must* use a subquery for the limits, as the
1577 # software based limiting can not be ported if this $rs is to be used
1578 # in a subquery itself (i.e. ->as_query)
1579 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1580 return $self->_count_subq_rs;
1583 return $self->_count_rs;
1588 # returns a ResultSetColumn object tied to the count query
1591 my ($self, $attrs) = @_;
1593 my $rsrc = $self->result_source;
1594 $attrs ||= $self->_resolved_attrs;
1596 my $tmp_attrs = { %$attrs };
1597 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1598 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1600 # overwrite the selector (supplied by the storage)
1601 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1602 $tmp_attrs->{as} = 'count';
1604 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1610 # same as above but uses a subquery
1612 sub _count_subq_rs {
1613 my ($self, $attrs) = @_;
1615 my $rsrc = $self->result_source;
1616 $attrs ||= $self->_resolved_attrs;
1618 my $sub_attrs = { %$attrs };
1619 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1620 delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/};
1622 # if we multi-prefetch we group_by something unique, as this is what we would
1623 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1624 if ( $attrs->{collapse} ) {
1625 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1626 $rsrc->_identifying_column_set || $self->throw_exception(
1627 'Unable to construct a unique group_by criteria properly collapsing the '
1628 . 'has_many prefetch before count()'
1633 # Calculate subquery selector
1634 if (my $g = $sub_attrs->{group_by}) {
1636 my $sql_maker = $rsrc->storage->sql_maker;
1638 # necessary as the group_by may refer to aliased functions
1640 for my $sel (@{$attrs->{select}}) {
1641 $sel_index->{$sel->{-as}} = $sel
1642 if (ref $sel eq 'HASH' and $sel->{-as});
1645 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1646 # also look for named aggregates referred in the having clause
1647 # having often contains scalarrefs - thus parse it out entirely
1649 if ($attrs->{having}) {
1650 local $sql_maker->{having_bind};
1651 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1652 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1653 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1654 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1655 # if we don't unset it we screw up retarded but unfortunately working
1656 # 'MAX(foo.bar)' => { '>', 3 }
1657 $sql_maker->{name_sep} = '';
1660 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1662 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1665 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1666 # and if all fails for an utterly naive quoted scalar-with-function
1667 while ($having_sql =~ /
1668 $rquote $sep $lquote (.+?) $rquote
1670 [\s,] \w+ \. (\w+) [\s,]
1672 [\s,] $lquote (.+?) $rquote [\s,]
1674 my $part = $1 || $2 || $3; # one of them matched if we got here
1675 unless ($seen_having{$part}++) {
1682 my $colpiece = $sel_index->{$_} || $_;
1684 # unqualify join-based group_by's. Arcane but possible query
1685 # also horrible horrible hack to alias a column (not a func.)
1686 # (probably need to introduce SQLA syntax)
1687 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1690 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1692 push @{$sub_attrs->{select}}, $colpiece;
1696 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1697 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1700 return $rsrc->resultset_class
1701 ->new ($rsrc, $sub_attrs)
1703 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1704 ->get_column ('count');
1711 =head2 count_literal
1713 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1714 should only be used in that context. See L</search_literal> for further info.
1718 =item Arguments: $sql_fragment, @standalone_bind_values
1720 =item Return Value: $count
1724 Counts the results in a literal query. Equivalent to calling L</search_literal>
1725 with the passed arguments, then L</count>.
1729 sub count_literal { shift->search_literal(@_)->count; }
1735 =item Arguments: none
1737 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1741 Returns all elements in the resultset.
1748 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1751 delete @{$self}{qw/stashed_rows stashed_objects/};
1753 if (my $c = $self->get_cache) {
1757 $self->cursor->reset;
1759 my $objs = $self->_construct_objects('fetch_all') || [];
1761 $self->set_cache($objs) if $self->{attrs}{cache};
1770 =item Arguments: none
1772 =item Return Value: $self
1776 Resets the resultset's cursor, so you can iterate through the elements again.
1777 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1785 delete @{$self}{qw/stashed_rows stashed_objects/};
1786 $self->{all_cache_position} = 0;
1787 $self->cursor->reset;
1795 =item Arguments: none
1797 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1801 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1802 an object for the first result (or C<undef> if the resultset is empty).
1807 return $_[0]->reset->next;
1813 # Determines whether and what type of subquery is required for the $rs operation.
1814 # If grouping is necessary either supplies its own, or verifies the current one
1815 # After all is done delegates to the proper storage method.
1817 sub _rs_update_delete {
1818 my ($self, $op, $values) = @_;
1820 my $rsrc = $self->result_source;
1821 my $storage = $rsrc->schema->storage;
1823 my $attrs = { %{$self->_resolved_attrs} };
1825 my $join_classifications;
1826 my $existing_group_by = delete $attrs->{group_by};
1828 # do we need a subquery for any reason?
1830 defined $existing_group_by
1832 # if {from} is unparseable wrap a subq
1833 ref($attrs->{from}) ne 'ARRAY'
1835 # limits call for a subq
1836 $self->_has_resolved_attr(qw/rows offset/)
1839 # simplify the joinmap, so we can further decide if a subq is necessary
1840 if (!$needs_subq and @{$attrs->{from}} > 1) {
1841 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1843 # check if there are any joins left after the prune
1844 if ( @{$attrs->{from}} > 1 ) {
1845 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1846 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1852 # any non-pruneable joins imply subq
1853 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1857 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1859 (ref $attrs->{from}[0]) ne 'HASH'
1861 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1865 # do we need anything like a subquery?
1866 if (! $needs_subq) {
1867 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1868 # a condition containing 'me' or other table prefixes will not work
1869 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1871 my $sqla = $rsrc->storage->sql_maker;
1872 local $sqla->{_dequalify_idents} = 1;
1873 \[ $sqla->_recurse_where($self->{cond}) ];
1877 # we got this far - means it is time to wrap a subquery
1878 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1880 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1886 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1887 delete $attrs->{$_} for qw/collapse select _prefetch_selector_range as/;
1888 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1889 $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins
1890 my $subrs = (ref $self)->new($rsrc, $attrs);
1892 if (@$idcols == 1) {
1893 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1895 elsif ($storage->_use_multicolumn_in) {
1896 # no syntax for calling this properly yet
1897 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1898 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1899 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1904 # if all else fails - get all primary keys and operate over a ORed set
1905 # wrap in a transaction for consistency
1906 # this is where the group_by/multiplication starts to matter
1910 keys %{ $join_classifications->{multiplying} || {} }
1912 # make sure if there is a supplied group_by it matches the columns compiled above
1913 # perfectly. Anything else can not be sanely executed on most databases so croak
1914 # right then and there
1915 if ($existing_group_by) {
1916 my @current_group_by = map
1917 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1922 join ("\x00", sort @current_group_by)
1924 join ("\x00", sort @{$attrs->{columns}} )
1926 $self->throw_exception (
1927 "You have just attempted a $op operation on a resultset which does group_by"
1928 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1929 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1930 . ' kind of queries. Please retry the operation with a modified group_by or'
1931 . ' without using one at all.'
1936 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1939 $guard = $storage->txn_scope_guard;
1942 for my $row ($subrs->cursor->all) {
1944 { $idcols->[$_] => $row->[$_] }
1951 my $res = $storage->$op (
1953 $op eq 'update' ? $values : (),
1957 $guard->commit if $guard;
1966 =item Arguments: \%values
1968 =item Return Value: $underlying_storage_rv
1972 Sets the specified columns in the resultset to the supplied values in a
1973 single query. Note that this will not run any accessor/set_column/update
1974 triggers, nor will it update any result object instances derived from this
1975 resultset (this includes the contents of the L<resultset cache|/set_cache>
1976 if any). See L</update_all> if you need to execute any on-update
1977 triggers or cascades defined either by you or a
1978 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1980 The return value is a pass through of what the underlying
1981 storage backend returned, and may vary. See L<DBI/execute> for the most
1986 Note that L</update> does not process/deflate any of the values passed in.
1987 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1988 ensure manually that any value passed to this method will stringify to
1989 something the RDBMS knows how to deal with. A notable example is the
1990 handling of L<DateTime> objects, for more info see:
1991 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1996 my ($self, $values) = @_;
1997 $self->throw_exception('Values for update must be a hash')
1998 unless ref $values eq 'HASH';
2000 return $self->_rs_update_delete ('update', $values);
2007 =item Arguments: \%values
2009 =item Return Value: 1
2013 Fetches all objects and updates them one at a time via
2014 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2015 triggers, while L</update> will not.
2020 my ($self, $values) = @_;
2021 $self->throw_exception('Values for update_all must be a hash')
2022 unless ref $values eq 'HASH';
2024 my $guard = $self->result_source->schema->txn_scope_guard;
2025 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2034 =item Arguments: none
2036 =item Return Value: $underlying_storage_rv
2040 Deletes the rows matching this resultset in a single query. Note that this
2041 will not run any delete triggers, nor will it alter the
2042 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2043 derived from this resultset (this includes the contents of the
2044 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2045 execute any on-delete triggers or cascades defined either by you or a
2046 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2048 The return value is a pass through of what the underlying storage backend
2049 returned, and may vary. See L<DBI/execute> for the most common case.
2055 $self->throw_exception('delete does not accept any arguments')
2058 return $self->_rs_update_delete ('delete');
2065 =item Arguments: none
2067 =item Return Value: 1
2071 Fetches all objects and deletes them one at a time via
2072 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2073 triggers, while L</delete> will not.
2079 $self->throw_exception('delete_all does not accept any arguments')
2082 my $guard = $self->result_source->schema->txn_scope_guard;
2083 $_->delete for $self->all;
2092 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2094 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2098 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2105 The context of this method call has an important effect on what is
2106 submitted to storage. In void context data is fed directly to fastpath
2107 insertion routines provided by the underlying storage (most often
2108 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2109 L<insert|DBIx::Class::Row/insert> calls on the
2110 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2111 augmentation of these methods provided by components. For example if you
2112 are using something like L<DBIx::Class::UUIDColumns> to create primary
2113 keys for you, you will find that your PKs are empty. In this case you
2114 will have to explicitly force scalar or list context in order to create
2119 In non-void (scalar or list) context, this method is simply a wrapper
2120 for L</create>. Depending on list or scalar context either a list of
2121 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2122 containing these objects is returned.
2124 When supplying data in "arrayref of arrayrefs" invocation style, the
2125 first element should be a list of column names and each subsequent
2126 element should be a data value in the earlier specified column order.
2129 $Arstist_rs->populate([
2130 [ qw( artistid name ) ],
2131 [ 100, 'A Formally Unknown Singer' ],
2132 [ 101, 'A singer that jumped the shark two albums ago' ],
2133 [ 102, 'An actually cool singer' ],
2136 For the arrayref of hashrefs style each hashref should be a structure
2137 suitable for passing to L</create>. Multi-create is also permitted with
2140 $schema->resultset("Artist")->populate([
2141 { artistid => 4, name => 'Manufactured Crap', cds => [
2142 { title => 'My First CD', year => 2006 },
2143 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2146 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2147 { title => 'My parents sold me to a record company', year => 2005 },
2148 { title => 'Why Am I So Ugly?', year => 2006 },
2149 { title => 'I Got Surgery and am now Popular', year => 2007 }
2154 If you attempt a void-context multi-create as in the example above (each
2155 Artist also has the related list of CDs), and B<do not> supply the
2156 necessary autoinc foreign key information, this method will proxy to the
2157 less efficient L</create>, and then throw the Result objects away. In this
2158 case there are obviously no benefits to using this method over L</create>.
2165 # cruft placed in standalone method
2166 my $data = $self->_normalize_populate_args(@_);
2168 return unless @$data;
2170 if(defined wantarray) {
2171 my @created = map { $self->create($_) } @$data;
2172 return wantarray ? @created : \@created;
2175 my $first = $data->[0];
2177 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2178 # it relationship data
2179 my (@rels, @columns);
2180 my $rsrc = $self->result_source;
2181 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2182 for (keys %$first) {
2183 my $ref = ref $first->{$_};
2184 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2190 my @pks = $rsrc->primary_columns;
2192 ## do the belongs_to relationships
2193 foreach my $index (0..$#$data) {
2195 # delegate to create() for any dataset without primary keys with specified relationships
2196 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2198 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2199 my @ret = $self->populate($data);
2205 foreach my $rel (@rels) {
2206 next unless ref $data->[$index]->{$rel} eq "HASH";
2207 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2208 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2209 my $related = $result->result_source->_resolve_condition(
2210 $reverse_relinfo->{cond},
2216 delete $data->[$index]->{$rel};
2217 $data->[$index] = {%{$data->[$index]}, %$related};
2219 push @columns, keys %$related if $index == 0;
2223 ## inherit the data locked in the conditions of the resultset
2224 my ($rs_data) = $self->_merge_with_rscond({});
2225 delete @{$rs_data}{@columns};
2227 ## do bulk insert on current row
2228 $rsrc->storage->insert_bulk(
2230 [@columns, keys %$rs_data],
2231 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2234 ## do the has_many relationships
2235 foreach my $item (@$data) {
2239 foreach my $rel (@rels) {
2240 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2242 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2244 my $child = $main_row->$rel;
2246 my $related = $child->result_source->_resolve_condition(
2247 $rels->{$rel}{cond},
2253 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2254 my @populate = map { {%$_, %$related} } @rows_to_add;
2256 $child->populate( \@populate );
2263 # populate() argumnets went over several incarnations
2264 # What we ultimately support is AoH
2265 sub _normalize_populate_args {
2266 my ($self, $arg) = @_;
2268 if (ref $arg eq 'ARRAY') {
2272 elsif (ref $arg->[0] eq 'HASH') {
2275 elsif (ref $arg->[0] eq 'ARRAY') {
2277 my @colnames = @{$arg->[0]};
2278 foreach my $values (@{$arg}[1 .. $#$arg]) {
2279 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2285 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2292 =item Arguments: none
2294 =item Return Value: L<$pager|Data::Page>
2298 Returns a L<Data::Page> object for the current resultset. Only makes
2299 sense for queries with a C<page> attribute.
2301 To get the full count of entries for a paged resultset, call
2302 C<total_entries> on the L<Data::Page> object.
2309 return $self->{pager} if $self->{pager};
2311 my $attrs = $self->{attrs};
2312 if (!defined $attrs->{page}) {
2313 $self->throw_exception("Can't create pager for non-paged rs");
2315 elsif ($attrs->{page} <= 0) {
2316 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2318 $attrs->{rows} ||= 10;
2320 # throw away the paging flags and re-run the count (possibly
2321 # with a subselect) to get the real total count
2322 my $count_attrs = { %$attrs };
2323 delete @{$count_attrs}{qw/rows offset page pager/};
2325 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2327 require DBIx::Class::ResultSet::Pager;
2328 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2329 sub { $total_rs->count }, #lazy-get the total
2331 $self->{attrs}{page},
2339 =item Arguments: $page_number
2341 =item Return Value: L<$resultset|/search>
2345 Returns a resultset for the $page_number page of the resultset on which page
2346 is called, where each page contains a number of rows equal to the 'rows'
2347 attribute set on the resultset (10 by default).
2352 my ($self, $page) = @_;
2353 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2360 =item Arguments: \%col_data
2362 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2366 Creates a new result object in the resultset's result class and returns
2367 it. The row is not inserted into the database at this point, call
2368 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2369 will tell you whether the result object has been inserted or not.
2371 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2376 my ($self, $values) = @_;
2378 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2381 $self->throw_exception( "new_result expects a hashref" )
2382 unless (ref $values eq 'HASH');
2384 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2388 @$cols_from_relations
2389 ? (-cols_from_relations => $cols_from_relations)
2391 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2394 return $self->result_class->new(\%new);
2397 # _merge_with_rscond
2399 # Takes a simple hash of K/V data and returns its copy merged with the
2400 # condition already present on the resultset. Additionally returns an
2401 # arrayref of value/condition names, which were inferred from related
2402 # objects (this is needed for in-memory related objects)
2403 sub _merge_with_rscond {
2404 my ($self, $data) = @_;
2406 my (%new_data, @cols_from_relations);
2408 my $alias = $self->{attrs}{alias};
2410 if (! defined $self->{cond}) {
2411 # just massage $data below
2413 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2414 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2415 @cols_from_relations = keys %new_data;
2417 elsif (ref $self->{cond} ne 'HASH') {
2418 $self->throw_exception(
2419 "Can't abstract implicit construct, resultset condition not a hash"
2423 # precendence must be given to passed values over values inherited from
2424 # the cond, so the order here is important.
2425 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2426 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2428 while ( my($col, $value) = each %implied ) {
2429 my $vref = ref $value;
2435 (keys %$value)[0] eq '='
2437 $new_data{$col} = $value->{'='};
2439 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2440 $new_data{$col} = $value;
2447 %{ $self->_remove_alias($data, $alias) },
2450 return (\%new_data, \@cols_from_relations);
2453 # _has_resolved_attr
2455 # determines if the resultset defines at least one
2456 # of the attributes supplied
2458 # used to determine if a subquery is neccessary
2460 # supports some virtual attributes:
2462 # This will scan for any joins being present on the resultset.
2463 # It is not a mere key-search but a deep inspection of {from}
2466 sub _has_resolved_attr {
2467 my ($self, @attr_names) = @_;
2469 my $attrs = $self->_resolved_attrs;
2473 for my $n (@attr_names) {
2474 if (grep { $n eq $_ } (qw/-join/) ) {
2475 $extra_checks{$n}++;
2479 my $attr = $attrs->{$n};
2481 next if not defined $attr;
2483 if (ref $attr eq 'HASH') {
2484 return 1 if keys %$attr;
2486 elsif (ref $attr eq 'ARRAY') {
2494 # a resolved join is expressed as a multi-level from
2496 $extra_checks{-join}
2498 ref $attrs->{from} eq 'ARRAY'
2500 @{$attrs->{from}} > 1
2508 # Recursively collapse the condition.
2510 sub _collapse_cond {
2511 my ($self, $cond, $collapsed) = @_;
2515 if (ref $cond eq 'ARRAY') {
2516 foreach my $subcond (@$cond) {
2517 next unless ref $subcond; # -or
2518 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2521 elsif (ref $cond eq 'HASH') {
2522 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2523 foreach my $subcond (@{$cond->{-and}}) {
2524 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2528 foreach my $col (keys %$cond) {
2529 my $value = $cond->{$col};
2530 $collapsed->{$col} = $value;
2540 # Remove the specified alias from the specified query hash. A copy is made so
2541 # the original query is not modified.
2544 my ($self, $query, $alias) = @_;
2546 my %orig = %{ $query || {} };
2549 foreach my $key (keys %orig) {
2551 $unaliased{$key} = $orig{$key};
2554 $unaliased{$1} = $orig{$key}
2555 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2565 =item Arguments: none
2567 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2571 Returns the SQL query and bind vars associated with the invocant.
2573 This is generally used as the RHS for a subquery.
2580 my $attrs = { %{ $self->_resolved_attrs } };
2585 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2586 # $sql also has no wrapping parenthesis in list ctx
2588 my $sqlbind = $self->result_source->storage
2589 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2598 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2600 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2604 my $artist = $schema->resultset('Artist')->find_or_new(
2605 { artist => 'fred' }, { key => 'artists' });
2607 $cd->cd_to_producer->find_or_new({ producer => $producer },
2608 { key => 'primary });
2610 Find an existing record from this resultset using L</find>. if none exists,
2611 instantiate a new result object and return it. The object will not be saved
2612 into your storage until you call L<DBIx::Class::Row/insert> on it.
2614 You most likely want this method when looking for existing rows using a unique
2615 constraint that is not the primary key, or looking for related rows.
2617 If you want objects to be saved immediately, use L</find_or_create> instead.
2619 B<Note>: Make sure to read the documentation of L</find> and understand the
2620 significance of the C<key> attribute, as its lack may skew your search, and
2621 subsequently result in spurious new objects.
2623 B<Note>: Take care when using C<find_or_new> with a table having
2624 columns with default values that you intend to be automatically
2625 supplied by the database (e.g. an auto_increment primary key column).
2626 In normal usage, the value of such columns should NOT be included at
2627 all in the call to C<find_or_new>, even when set to C<undef>.
2633 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2634 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2635 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2638 return $self->new_result($hash);
2645 =item Arguments: \%col_data
2647 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2651 Attempt to create a single new row or a row with multiple related rows
2652 in the table represented by the resultset (and related tables). This
2653 will not check for duplicate rows before inserting, use
2654 L</find_or_create> to do that.
2656 To create one row for this resultset, pass a hashref of key/value
2657 pairs representing the columns of the table and the values you wish to
2658 store. If the appropriate relationships are set up, foreign key fields
2659 can also be passed an object representing the foreign row, and the
2660 value will be set to its primary key.
2662 To create related objects, pass a hashref of related-object column values
2663 B<keyed on the relationship name>. If the relationship is of type C<multi>
2664 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2665 The process will correctly identify columns holding foreign keys, and will
2666 transparently populate them from the keys of the corresponding relation.
2667 This can be applied recursively, and will work correctly for a structure
2668 with an arbitrary depth and width, as long as the relationships actually
2669 exists and the correct column data has been supplied.
2671 Instead of hashrefs of plain related data (key/value pairs), you may
2672 also pass new or inserted objects. New objects (not inserted yet, see
2673 L</new_result>), will be inserted into their appropriate tables.
2675 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2677 Example of creating a new row.
2679 $person_rs->create({
2680 name=>"Some Person",
2681 email=>"somebody@someplace.com"
2684 Example of creating a new row and also creating rows in a related C<has_many>
2685 or C<has_one> resultset. Note Arrayref.
2688 { artistid => 4, name => 'Manufactured Crap', cds => [
2689 { title => 'My First CD', year => 2006 },
2690 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2695 Example of creating a new row and also creating a row in a related
2696 C<belongs_to> resultset. Note Hashref.
2699 title=>"Music for Silly Walks",
2702 name=>"Silly Musician",
2710 When subclassing ResultSet never attempt to override this method. Since
2711 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2712 lot of the internals simply never call it, so your override will be
2713 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2714 or L<DBIx::Class::Row/insert> depending on how early in the
2715 L</create> process you need to intervene. See also warning pertaining to
2723 my ($self, $attrs) = @_;
2724 $self->throw_exception( "create needs a hashref" )
2725 unless ref $attrs eq 'HASH';
2726 return $self->new_result($attrs)->insert;
2729 =head2 find_or_create
2733 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2735 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2739 $cd->cd_to_producer->find_or_create({ producer => $producer },
2740 { key => 'primary' });
2742 Tries to find a record based on its primary key or unique constraints; if none
2743 is found, creates one and returns that instead.
2745 my $cd = $schema->resultset('CD')->find_or_create({
2747 artist => 'Massive Attack',
2748 title => 'Mezzanine',
2752 Also takes an optional C<key> attribute, to search by a specific key or unique
2753 constraint. For example:
2755 my $cd = $schema->resultset('CD')->find_or_create(
2757 artist => 'Massive Attack',
2758 title => 'Mezzanine',
2760 { key => 'cd_artist_title' }
2763 B<Note>: Make sure to read the documentation of L</find> and understand the
2764 significance of the C<key> attribute, as its lack may skew your search, and
2765 subsequently result in spurious row creation.
2767 B<Note>: Because find_or_create() reads from the database and then
2768 possibly inserts based on the result, this method is subject to a race
2769 condition. Another process could create a record in the table after
2770 the find has completed and before the create has started. To avoid
2771 this problem, use find_or_create() inside a transaction.
2773 B<Note>: Take care when using C<find_or_create> with a table having
2774 columns with default values that you intend to be automatically
2775 supplied by the database (e.g. an auto_increment primary key column).
2776 In normal usage, the value of such columns should NOT be included at
2777 all in the call to C<find_or_create>, even when set to C<undef>.
2779 See also L</find> and L</update_or_create>. For information on how to declare
2780 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2782 If you need to know if an existing row was found or a new one created use
2783 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2784 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2787 my $cd = $schema->resultset('CD')->find_or_new({
2789 artist => 'Massive Attack',
2790 title => 'Mezzanine',
2794 if( !$cd->in_storage ) {
2801 sub find_or_create {
2803 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2804 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2805 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2808 return $self->create($hash);
2811 =head2 update_or_create
2815 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2817 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2821 $resultset->update_or_create({ col => $val, ... });
2823 Like L</find_or_create>, but if a row is found it is immediately updated via
2824 C<< $found_row->update (\%col_data) >>.
2827 Takes an optional C<key> attribute to search on a specific unique constraint.
2830 # In your application
2831 my $cd = $schema->resultset('CD')->update_or_create(
2833 artist => 'Massive Attack',
2834 title => 'Mezzanine',
2837 { key => 'cd_artist_title' }
2840 $cd->cd_to_producer->update_or_create({
2841 producer => $producer,
2847 B<Note>: Make sure to read the documentation of L</find> and understand the
2848 significance of the C<key> attribute, as its lack may skew your search, and
2849 subsequently result in spurious row creation.
2851 B<Note>: Take care when using C<update_or_create> with a table having
2852 columns with default values that you intend to be automatically
2853 supplied by the database (e.g. an auto_increment primary key column).
2854 In normal usage, the value of such columns should NOT be included at
2855 all in the call to C<update_or_create>, even when set to C<undef>.
2857 See also L</find> and L</find_or_create>. For information on how to declare
2858 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2860 If you need to know if an existing row was updated or a new one created use
2861 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2862 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2867 sub update_or_create {
2869 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2870 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2872 my $row = $self->find($cond, $attrs);
2874 $row->update($cond);
2878 return $self->create($cond);
2881 =head2 update_or_new
2885 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2887 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2891 $resultset->update_or_new({ col => $val, ... });
2893 Like L</find_or_new> but if a row is found it is immediately updated via
2894 C<< $found_row->update (\%col_data) >>.
2898 # In your application
2899 my $cd = $schema->resultset('CD')->update_or_new(
2901 artist => 'Massive Attack',
2902 title => 'Mezzanine',
2905 { key => 'cd_artist_title' }
2908 if ($cd->in_storage) {
2909 # the cd was updated
2912 # the cd is not yet in the database, let's insert it
2916 B<Note>: Make sure to read the documentation of L</find> and understand the
2917 significance of the C<key> attribute, as its lack may skew your search, and
2918 subsequently result in spurious new objects.
2920 B<Note>: Take care when using C<update_or_new> with a table having
2921 columns with default values that you intend to be automatically
2922 supplied by the database (e.g. an auto_increment primary key column).
2923 In normal usage, the value of such columns should NOT be included at
2924 all in the call to C<update_or_new>, even when set to C<undef>.
2926 See also L</find>, L</find_or_create> and L</find_or_new>.
2932 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2933 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2935 my $row = $self->find( $cond, $attrs );
2936 if ( defined $row ) {
2937 $row->update($cond);
2941 return $self->new_result($cond);
2948 =item Arguments: none
2950 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2954 Gets the contents of the cache for the resultset, if the cache is set.
2956 The cache is populated either by using the L</prefetch> attribute to
2957 L</search> or by calling L</set_cache>.
2969 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2971 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2975 Sets the contents of the cache for the resultset. Expects an arrayref
2976 of objects of the same class as those produced by the resultset. Note that
2977 if the cache is set, the resultset will return the cached objects rather
2978 than re-querying the database even if the cache attr is not set.
2980 The contents of the cache can also be populated by using the
2981 L</prefetch> attribute to L</search>.
2986 my ( $self, $data ) = @_;
2987 $self->throw_exception("set_cache requires an arrayref")
2988 if defined($data) && (ref $data ne 'ARRAY');
2989 $self->{all_cache} = $data;
2996 =item Arguments: none
2998 =item Return Value: undef
3002 Clears the cache for the resultset.
3007 shift->set_cache(undef);
3014 =item Arguments: none
3016 =item Return Value: true, if the resultset has been paginated
3024 return !!$self->{attrs}{page};
3031 =item Arguments: none
3033 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3041 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3044 =head2 related_resultset
3048 =item Arguments: $rel_name
3050 =item Return Value: L<$resultset|/search>
3054 Returns a related resultset for the supplied relationship name.
3056 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3060 sub related_resultset {
3061 my ($self, $rel) = @_;
3063 return $self->{related_resultsets}{$rel} ||= do {
3064 my $rsrc = $self->result_source;
3065 my $rel_info = $rsrc->relationship_info($rel);
3067 $self->throw_exception(
3068 "search_related: result source '" . $rsrc->source_name .
3069 "' has no such relationship $rel")
3072 my $attrs = $self->_chain_relationship($rel);
3074 my $join_count = $attrs->{seen_join}{$rel};
3076 my $alias = $self->result_source->storage
3077 ->relname_to_table_alias($rel, $join_count);
3079 # since this is search_related, and we already slid the select window inwards
3080 # (the select/as attrs were deleted in the beginning), we need to flip all
3081 # left joins to inner, so we get the expected results
3082 # read the comment on top of the actual function to see what this does
3083 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3086 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3087 delete @{$attrs}{qw(result_class alias)};
3091 if (my $cache = $self->get_cache) {
3092 $related_cache = [ map
3093 { @{$_->related_resultset($rel)->get_cache||[]} }
3098 my $rel_source = $rsrc->related_source($rel);
3102 # The reason we do this now instead of passing the alias to the
3103 # search_rs below is that if you wrap/overload resultset on the
3104 # source you need to know what alias it's -going- to have for things
3105 # to work sanely (e.g. RestrictWithObject wants to be able to add
3106 # extra query restrictions, and these may need to be $alias.)
3108 my $rel_attrs = $rel_source->resultset_attributes;
3109 local $rel_attrs->{alias} = $alias;
3111 $rel_source->resultset
3115 where => $attrs->{where},
3118 $new->set_cache($related_cache) if $related_cache;
3123 =head2 current_source_alias
3127 =item Arguments: none
3129 =item Return Value: $source_alias
3133 Returns the current table alias for the result source this resultset is built
3134 on, that will be used in the SQL query. Usually it is C<me>.
3136 Currently the source alias that refers to the result set returned by a
3137 L</search>/L</find> family method depends on how you got to the resultset: it's
3138 C<me> by default, but eg. L</search_related> aliases it to the related result
3139 source name (and keeps C<me> referring to the original result set). The long
3140 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3141 (and make this method unnecessary).
3143 Thus it's currently necessary to use this method in predefined queries (see
3144 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3145 source alias of the current result set:
3147 # in a result set class
3149 my ($self, $user) = @_;
3151 my $me = $self->current_source_alias;
3153 return $self->search({
3154 "$me.modified" => $user->id,
3160 sub current_source_alias {
3161 return (shift->{attrs} || {})->{alias} || 'me';
3164 =head2 as_subselect_rs
3168 =item Arguments: none
3170 =item Return Value: L<$resultset|/search>
3174 Act as a barrier to SQL symbols. The resultset provided will be made into a
3175 "virtual view" by including it as a subquery within the from clause. From this
3176 point on, any joined tables are inaccessible to ->search on the resultset (as if
3177 it were simply where-filtered without joins). For example:
3179 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3181 # 'x' now pollutes the query namespace
3183 # So the following works as expected
3184 my $ok_rs = $rs->search({'x.other' => 1});
3186 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3187 # def) we look for one row with contradictory terms and join in another table
3188 # (aliased 'x_2') which we never use
3189 my $broken_rs = $rs->search({'x.name' => 'def'});
3191 my $rs2 = $rs->as_subselect_rs;
3193 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3194 my $not_joined_rs = $rs2->search({'x.other' => 1});
3196 # works as expected: finds a 'table' row related to two x rows (abc and def)
3197 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3199 Another example of when one might use this would be to select a subset of
3200 columns in a group by clause:
3202 my $rs = $schema->resultset('Bar')->search(undef, {
3203 group_by => [qw{ id foo_id baz_id }],
3204 })->as_subselect_rs->search(undef, {
3205 columns => [qw{ id foo_id }]
3208 In the above example normally columns would have to be equal to the group by,
3209 but because we isolated the group by into a subselect the above works.
3213 sub as_subselect_rs {
3216 my $attrs = $self->_resolved_attrs;
3218 my $fresh_rs = (ref $self)->new (
3219 $self->result_source
3222 # these pieces will be locked in the subquery
3223 delete $fresh_rs->{cond};
3224 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3226 return $fresh_rs->search( {}, {
3228 $attrs->{alias} => $self->as_query,
3229 -alias => $attrs->{alias},
3230 -rsrc => $self->result_source,
3232 alias => $attrs->{alias},
3236 # This code is called by search_related, and makes sure there
3237 # is clear separation between the joins before, during, and
3238 # after the relationship. This information is needed later
3239 # in order to properly resolve prefetch aliases (any alias
3240 # with a relation_chain_depth less than the depth of the
3241 # current prefetch is not considered)
3243 # The increments happen twice per join. An even number means a
3244 # relationship specified via a search_related, whereas an odd
3245 # number indicates a join/prefetch added via attributes
3247 # Also this code will wrap the current resultset (the one we
3248 # chain to) in a subselect IFF it contains limiting attributes
3249 sub _chain_relationship {
3250 my ($self, $rel) = @_;
3251 my $source = $self->result_source;
3252 my $attrs = { %{$self->{attrs}||{}} };
3254 # we need to take the prefetch the attrs into account before we
3255 # ->_resolve_join as otherwise they get lost - captainL
3256 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3258 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
3260 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3263 my @force_subq_attrs = qw/offset rows group_by having/;
3266 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3268 $self->_has_resolved_attr (@force_subq_attrs)
3270 # Nuke the prefetch (if any) before the new $rs attrs
3271 # are resolved (prefetch is useless - we are wrapping
3272 # a subquery anyway).
3273 my $rs_copy = $self->search;
3274 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3275 $rs_copy->{attrs}{join},
3276 delete $rs_copy->{attrs}{prefetch},
3281 -alias => $attrs->{alias},
3282 $attrs->{alias} => $rs_copy->as_query,
3284 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3285 $seen->{-relation_chain_depth} = 0;
3287 elsif ($attrs->{from}) { #shallow copy suffices
3288 $from = [ @{$attrs->{from}} ];
3293 -alias => $attrs->{alias},
3294 $attrs->{alias} => $source->from,
3298 my $jpath = ($seen->{-relation_chain_depth})
3299 ? $from->[-1][0]{-join_path}
3302 my @requested_joins = $source->_resolve_join(
3309 push @$from, @requested_joins;
3311 $seen->{-relation_chain_depth}++;
3313 # if $self already had a join/prefetch specified on it, the requested
3314 # $rel might very well be already included. What we do in this case
3315 # is effectively a no-op (except that we bump up the chain_depth on
3316 # the join in question so we could tell it *is* the search_related)
3319 # we consider the last one thus reverse
3320 for my $j (reverse @requested_joins) {
3321 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3322 if ($rel eq $last_j) {
3323 $j->[0]{-relation_chain_depth}++;
3329 unless ($already_joined) {
3330 push @$from, $source->_resolve_join(
3338 $seen->{-relation_chain_depth}++;
3340 return {%$attrs, from => $from, seen_join => $seen};
3343 # FIXME - this needs to go live in Schema with the tree walker... or
3345 my $inflatemap_checker;
3346 $inflatemap_checker = sub {
3347 my ($rsrc, $relpaths) = @_;
3352 $_ =~ /^ ( [^\.]+ ) \. (.+) $/x
3355 push @{$rels->{$1}}, $2;
3358 for my $rel (keys %$rels) {
3359 my $rel_rsrc = try {
3360 $rsrc->related_source ($rel)
3362 $rsrc->throw_exception(sprintf(
3363 "Inflation into non-existent relationship '%s' of '%s' requested, "
3364 . "check the inflation specification (columns/as) ending in '...%s.%s'",
3368 ( sort { length($a) <=> length ($b) } @{$rels->{$rel}} )[0],
3371 $inflatemap_checker->($rel_rsrc, $rels->{$rel});
3377 sub _resolved_attrs {
3379 return $self->{_attrs} if $self->{_attrs};
3381 my $attrs = { %{ $self->{attrs} || {} } };
3382 my $source = $self->result_source;
3383 my $alias = $attrs->{alias};
3385 # default selection list
3386 $attrs->{columns} = [ $source->columns ]
3387 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3389 # merge selectors together
3390 for (qw/columns select as/) {
3391 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3392 if $attrs->{$_} or $attrs->{"+$_"};
3395 # disassemble columns
3397 if (my $cols = delete $attrs->{columns}) {
3398 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3399 if (ref $c eq 'HASH') {
3400 for my $as (sort keys %$c) {
3401 push @sel, $c->{$as};
3412 # when trying to weed off duplicates later do not go past this point -
3413 # everything added from here on is unbalanced "anyone's guess" stuff
3414 my $dedup_stop_idx = $#as;
3416 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3418 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3419 if $attrs->{select};
3421 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3422 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3424 # disqualify all $alias.col as-bits (inflate-map mandated)
3425 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3427 # de-duplicate the result (remove *identical* select/as pairs)
3428 # and also die on duplicate {as} pointing to different {select}s
3429 # not using a c-style for as the condition is prone to shrinkage
3432 while ($i <= $dedup_stop_idx) {
3433 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3438 elsif ($seen->{$as[$i]}++) {
3439 $self->throw_exception(
3440 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3448 # validate the user-supplied 'as' chain
3449 # folks get too confused by the (logical) exception message, need to
3450 # go to some lengths to clarify the text
3452 # FIXME - this needs to go live in Schema with the tree walker... or
3454 $inflatemap_checker->($source, \@as);
3456 $attrs->{select} = \@sel;
3457 $attrs->{as} = \@as;
3459 $attrs->{from} ||= [{
3461 -alias => $self->{attrs}{alias},
3462 $self->{attrs}{alias} => $source->from,
3465 if ( $attrs->{join} || $attrs->{prefetch} ) {
3467 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3468 if ref $attrs->{from} ne 'ARRAY';
3470 my $join = (delete $attrs->{join}) || {};
3472 if ( defined $attrs->{prefetch} ) {
3473 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3476 $attrs->{from} = # have to copy here to avoid corrupting the original
3478 @{ $attrs->{from} },
3479 $source->_resolve_join(
3482 { %{ $attrs->{seen_join} || {} } },
3483 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3484 ? $attrs->{from}[-1][0]{-join_path}
3491 if ( defined $attrs->{order_by} ) {
3492 $attrs->{order_by} = (
3493 ref( $attrs->{order_by} ) eq 'ARRAY'
3494 ? [ @{ $attrs->{order_by} } ]
3495 : [ $attrs->{order_by} || () ]
3499 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3500 $attrs->{group_by} = [ $attrs->{group_by} ];
3503 # generate the distinct induced group_by early, as prefetch will be carried via a
3504 # subquery (since a group_by is present)
3505 if (delete $attrs->{distinct}) {
3506 if ($attrs->{group_by}) {
3507 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3510 # distinct affects only the main selection part, not what prefetch may
3512 $attrs->{group_by} = $source->storage->_group_over_selection (
3520 # generate selections based on the prefetch helper
3522 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3523 if defined $attrs->{prefetch};
3527 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3528 if $attrs->{_dark_selector};
3530 $attrs->{collapse} = 1;
3532 # this is a separate structure (we don't look in {from} directly)
3533 # as the resolver needs to shift things off the lists to work
3534 # properly (identical-prefetches on different branches)
3536 if (ref $attrs->{from} eq 'ARRAY') {
3538 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3540 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3541 next unless $j->[0]{-alias};
3542 next unless $j->[0]{-join_path};
3543 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3545 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3548 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3549 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3553 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3555 # we need to somehow mark which columns came from prefetch
3557 my $sel_end = $#{$attrs->{select}};
3558 $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
3561 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3562 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3565 if ( ! List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3566 $attrs->{_single_resultclass_inflation} = 1;
3567 $attrs->{collapse} = 0;
3570 # run through the resulting joinstructure (starting from our current slot)
3571 # and unset collapse if proven unnesessary
3573 # also while we are at it find out if the current root source has
3574 # been premultiplied by previous related_source chaining
3576 # this allows to predict whether a root object with all other relation
3577 # data set to NULL is in fact unique
3578 if ($attrs->{collapse}) {
3580 if (ref $attrs->{from} eq 'ARRAY') {
3582 if (@{$attrs->{from}} <= 1) {
3583 # no joins - no collapse
3584 $attrs->{collapse} = 0;
3587 # find where our table-spec starts
3588 my @fromlist = @{$attrs->{from}};
3590 my $t = shift @fromlist;
3593 # me vs join from-spec distinction - a ref means non-root
3594 if (ref $t eq 'ARRAY') {
3596 $is_multi ||= ! $t->{-is_single};
3598 last if ($t->{-alias} && $t->{-alias} eq $alias);
3599 $attrs->{_main_source_premultiplied} ||= $is_multi;
3602 # no non-singles remaining, nor any premultiplication - nothing to collapse
3604 ! $attrs->{_main_source_premultiplied}
3606 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3608 $attrs->{collapse} = 0;
3614 # if we can not analyze the from - err on the side of safety
3615 $attrs->{_main_source_premultiplied} = 1;
3619 # if both page and offset are specified, produce a combined offset
3620 # even though it doesn't make much sense, this is what pre 081xx has
3622 if (my $page = delete $attrs->{page}) {
3624 ($attrs->{rows} * ($page - 1))
3626 ($attrs->{offset} || 0)
3630 return $self->{_attrs} = $attrs;
3634 my ($self, $attr) = @_;
3636 if (ref $attr eq 'HASH') {
3637 return $self->_rollout_hash($attr);
3638 } elsif (ref $attr eq 'ARRAY') {
3639 return $self->_rollout_array($attr);
3645 sub _rollout_array {
3646 my ($self, $attr) = @_;
3649 foreach my $element (@{$attr}) {
3650 if (ref $element eq 'HASH') {
3651 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3652 } elsif (ref $element eq 'ARRAY') {
3653 # XXX - should probably recurse here
3654 push( @rolled_array, @{$self->_rollout_array($element)} );
3656 push( @rolled_array, $element );
3659 return \@rolled_array;
3663 my ($self, $attr) = @_;
3666 foreach my $key (keys %{$attr}) {
3667 push( @rolled_array, { $key => $attr->{$key} } );
3669 return \@rolled_array;
3672 sub _calculate_score {
3673 my ($self, $a, $b) = @_;
3675 if (defined $a xor defined $b) {
3678 elsif (not defined $a) {
3682 if (ref $b eq 'HASH') {
3683 my ($b_key) = keys %{$b};
3684 if (ref $a eq 'HASH') {
3685 my ($a_key) = keys %{$a};
3686 if ($a_key eq $b_key) {
3687 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3692 return ($a eq $b_key) ? 1 : 0;
3695 if (ref $a eq 'HASH') {
3696 my ($a_key) = keys %{$a};
3697 return ($b eq $a_key) ? 1 : 0;
3699 return ($b eq $a) ? 1 : 0;
3704 sub _merge_joinpref_attr {
3705 my ($self, $orig, $import) = @_;
3707 return $import unless defined($orig);
3708 return $orig unless defined($import);
3710 $orig = $self->_rollout_attr($orig);
3711 $import = $self->_rollout_attr($import);
3714 foreach my $import_element ( @{$import} ) {
3715 # find best candidate from $orig to merge $b_element into
3716 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3717 foreach my $orig_element ( @{$orig} ) {
3718 my $score = $self->_calculate_score( $orig_element, $import_element );
3719 if ($score > $best_candidate->{score}) {
3720 $best_candidate->{position} = $position;
3721 $best_candidate->{score} = $score;
3725 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3726 $import_key = '' if not defined $import_key;
3728 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3729 push( @{$orig}, $import_element );
3731 my $orig_best = $orig->[$best_candidate->{position}];
3732 # merge orig_best and b_element together and replace original with merged
3733 if (ref $orig_best ne 'HASH') {
3734 $orig->[$best_candidate->{position}] = $import_element;
3735 } elsif (ref $import_element eq 'HASH') {
3736 my ($key) = keys %{$orig_best};
3737 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3740 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3743 return @$orig ? $orig : ();
3751 require Hash::Merge;
3752 my $hm = Hash::Merge->new;
3754 $hm->specify_behavior({
3757 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3759 if ($defl xor $defr) {
3760 return [ $defl ? $_[0] : $_[1] ];
3765 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3769 return [$_[0], $_[1]];
3773 return $_[1] if !defined $_[0];
3774 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3775 return [$_[0], @{$_[1]}]
3778 return [] if !defined $_[0] and !keys %{$_[1]};
3779 return [ $_[1] ] if !defined $_[0];
3780 return [ $_[0] ] if !keys %{$_[1]};
3781 return [$_[0], $_[1]]
3786 return $_[0] if !defined $_[1];
3787 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3788 return [@{$_[0]}, $_[1]]
3791 my @ret = @{$_[0]} or return $_[1];
3792 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3793 my %idx = map { $_ => 1 } @ret;
3794 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3798 return [ $_[1] ] if ! @{$_[0]};
3799 return $_[0] if !keys %{$_[1]};
3800 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3801 return [ @{$_[0]}, $_[1] ];
3806 return [] if !keys %{$_[0]} and !defined $_[1];
3807 return [ $_[0] ] if !defined $_[1];
3808 return [ $_[1] ] if !keys %{$_[0]};
3809 return [$_[0], $_[1]]
3812 return [] if !keys %{$_[0]} and !@{$_[1]};
3813 return [ $_[0] ] if !@{$_[1]};
3814 return $_[1] if !keys %{$_[0]};
3815 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3816 return [ $_[0], @{$_[1]} ];
3819 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3820 return [ $_[0] ] if !keys %{$_[1]};
3821 return [ $_[1] ] if !keys %{$_[0]};
3822 return [ $_[0] ] if $_[0] eq $_[1];
3823 return [ $_[0], $_[1] ];
3826 } => 'DBIC_RS_ATTR_MERGER');
3830 return $hm->merge ($_[1], $_[2]);
3834 sub STORABLE_freeze {
3835 my ($self, $cloning) = @_;
3836 my $to_serialize = { %$self };
3838 # A cursor in progress can't be serialized (and would make little sense anyway)
3839 # the parser can be regenerated (and can't be serialized)
3840 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3842 # nor is it sensical to store a not-yet-fired-count pager
3843 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3844 delete $to_serialize->{pager};
3847 Storable::nfreeze($to_serialize);
3850 # need this hook for symmetry
3852 my ($self, $cloning, $serialized) = @_;
3854 %$self = %{ Storable::thaw($serialized) };
3860 =head2 throw_exception
3862 See L<DBIx::Class::Schema/throw_exception> for details.
3866 sub throw_exception {
3869 if (ref $self and my $rsrc = $self->result_source) {
3870 $rsrc->throw_exception(@_)
3873 DBIx::Class::Exception->throw(@_);
3881 # XXX: FIXME: Attributes docs need clearing up
3885 Attributes are used to refine a ResultSet in various ways when
3886 searching for data. They can be passed to any method which takes an
3887 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3890 Default attributes can be set on the result class using
3891 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3892 the CAVEATS on that feature before using it!)
3894 These are in no particular order:
3900 =item Value: ( $order_by | \@order_by | \%order_by )
3904 Which column(s) to order the results by.
3906 [The full list of suitable values is documented in
3907 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3910 If a single column name, or an arrayref of names is supplied, the
3911 argument is passed through directly to SQL. The hashref syntax allows
3912 for connection-agnostic specification of ordering direction:
3914 For descending order:
3916 order_by => { -desc => [qw/col1 col2 col3/] }
3918 For explicit ascending order:
3920 order_by => { -asc => 'col' }
3922 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3923 supported, although you are strongly encouraged to use the hashref
3924 syntax as outlined above.
3930 =item Value: \@columns | \%columns | $column
3934 Shortcut to request a particular set of columns to be retrieved. Each
3935 column spec may be a string (a table column name), or a hash (in which
3936 case the key is the C<as> value, and the value is used as the C<select>
3937 expression). Adds C<me.> onto the start of any column without a C<.> in
3938 it and sets C<select> from that, then auto-populates C<as> from
3939 C<select> as normal. (You may also use the C<cols> attribute, as in
3940 earlier versions of DBIC.)
3942 Essentially C<columns> does the same as L</select> and L</as>.
3944 columns => [ 'foo', { bar => 'baz' } ]
3948 select => [qw/foo baz/],
3955 =item Value: \@columns
3959 Indicates additional columns to be selected from storage. Works the same
3960 as L</columns> but adds columns to the selection. (You may also use the
3961 C<include_columns> attribute, as in earlier versions of DBIC). For
3964 $schema->resultset('CD')->search(undef, {
3965 '+columns' => ['artist.name'],
3969 would return all CDs and include a 'name' column to the information
3970 passed to object inflation. Note that the 'artist' is the name of the
3971 column (or relationship) accessor, and 'name' is the name of the column
3972 accessor in the related table.
3974 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3975 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3976 unary plus operator before it.
3978 =head2 include_columns
3982 =item Value: \@columns
3986 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3992 =item Value: \@select_columns
3996 Indicates which columns should be selected from the storage. You can use
3997 column names, or in the case of RDBMS back ends, function or stored procedure
4000 $rs = $schema->resultset('Employee')->search(undef, {
4003 { count => 'employeeid' },
4004 { max => { length => 'name' }, -as => 'longest_name' }
4009 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
4011 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
4012 use L</select>, to instruct DBIx::Class how to store the result of the column.
4013 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
4014 identifier aliasing. You can however alias a function, so you can use it in
4015 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
4016 attribute> supplied as shown in the example above.
4018 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
4019 Not doing so causes Perl to incorrectly interpret them as a bareword with a
4020 unary plus operator before it.
4026 Indicates additional columns to be selected from storage. Works the same as
4027 L</select> but adds columns to the default selection, instead of specifying
4036 =item Value: \@inflation_names
4040 Indicates column names for object inflation. That is L</as> indicates the
4041 slot name in which the column value will be stored within the
4042 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4043 identifier by the C<get_column> method (or via the object accessor B<if one
4044 with the same name already exists>) as shown below. The L</as> attribute has
4045 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4047 $rs = $schema->resultset('Employee')->search(undef, {
4050 { count => 'employeeid' },
4051 { max => { length => 'name' }, -as => 'longest_name' }
4060 If the object against which the search is performed already has an accessor
4061 matching a column name specified in C<as>, the value can be retrieved using
4062 the accessor as normal:
4064 my $name = $employee->name();
4066 If on the other hand an accessor does not exist in the object, you need to
4067 use C<get_column> instead:
4069 my $employee_count = $employee->get_column('employee_count');
4071 You can create your own accessors if required - see
4072 L<DBIx::Class::Manual::Cookbook> for details.
4078 Indicates additional column names for those added via L</+select>. See L</as>.
4086 =item Value: ($rel_name | \@rel_names | \%rel_names)
4090 Contains a list of relationships that should be joined for this query. For
4093 # Get CDs by Nine Inch Nails
4094 my $rs = $schema->resultset('CD')->search(
4095 { 'artist.name' => 'Nine Inch Nails' },
4096 { join => 'artist' }
4099 Can also contain a hash reference to refer to the other relation's relations.
4102 package MyApp::Schema::Track;
4103 use base qw/DBIx::Class/;
4104 __PACKAGE__->table('track');
4105 __PACKAGE__->add_columns(qw/trackid cd position title/);
4106 __PACKAGE__->set_primary_key('trackid');
4107 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4110 # In your application
4111 my $rs = $schema->resultset('Artist')->search(
4112 { 'track.title' => 'Teardrop' },
4114 join => { cd => 'track' },
4115 order_by => 'artist.name',
4119 You need to use the relationship (not the table) name in conditions,
4120 because they are aliased as such. The current table is aliased as "me", so
4121 you need to use me.column_name in order to avoid ambiguity. For example:
4123 # Get CDs from 1984 with a 'Foo' track
4124 my $rs = $schema->resultset('CD')->search(
4127 'tracks.name' => 'Foo'
4129 { join => 'tracks' }
4132 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4133 similarly for a third time). For e.g.
4135 my $rs = $schema->resultset('Artist')->search({
4136 'cds.title' => 'Down to Earth',
4137 'cds_2.title' => 'Popular',
4139 join => [ qw/cds cds/ ],
4142 will return a set of all artists that have both a cd with title 'Down
4143 to Earth' and a cd with title 'Popular'.
4145 If you want to fetch related objects from other tables as well, see L</prefetch>
4148 NOTE: An internal join-chain pruner will discard certain joins while
4149 constructing the actual SQL query, as long as the joins in question do not
4150 affect the retrieved result. This for example includes 1:1 left joins
4151 that are not part of the restriction specification (WHERE/HAVING) nor are
4152 a part of the query selection.
4154 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4160 =item Value: (0 | 1)
4164 When set to a true value, indicates that any rows fetched from joined has_many
4165 relationships are to be aggregated into the corresponding "parent" object. For
4166 example, the resultset:
4168 my $rs = $schema->resultset('CD')->search({}, {
4169 '+columns' => [ qw/ tracks.title tracks.position / ],
4174 While executing the following query:
4176 SELECT me.*, tracks.title, tracks.position
4178 LEFT JOIN track tracks
4179 ON tracks.cdid = me.cdid
4181 Will return only as many objects as there are rows in the CD source, even
4182 though the result of the query may span many rows. Each of these CD objects
4183 will in turn have multiple "Track" objects hidden behind the has_many
4184 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4185 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4186 product"), with each CD object containing exactly one of all fetched Track data.
4188 When a collapse is requested on a non-ordered resultset, an order by some
4189 unique part of the main source (the left-most table) is inserted automatically.
4190 This is done so that the resultset is allowed to be "lazy" - calling
4191 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4192 object with all of its related data.
4194 If an L</order_by> is already declared, and orders the resultset in a way that
4195 makes collapsing as described above impossible (e.g. C<< ORDER BY
4196 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4197 switch to "eager" mode and slurp the entire resultset before consturcting the
4198 first object returned by L</next>.
4200 Setting this attribute on a resultset that does not join any has_many
4201 relations is a no-op.
4203 For a more in-depth discussion, see L</PREFETCHING>.
4209 =item Value: ($rel_name | \@rel_names | \%rel_names)
4213 This attribute is a shorthand for specifying a L</join> spec, adding all
4214 columns from the joined related sources as L</+columns> and setting
4215 L</collapse> to a true value. For example, the following two queries are
4218 my $rs = $schema->resultset('Artist')->search({}, {
4219 prefetch => { cds => ['genre', 'tracks' ] },
4224 my $rs = $schema->resultset('Artist')->search({}, {
4225 join => { cds => ['genre', 'tracks' ] },
4229 { +{ "cds.$_" => "cds.$_" } }
4230 $schema->source('Artist')->related_source('cds')->columns
4233 { +{ "cds.genre.$_" => "genre.$_" } }
4234 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4237 { +{ "cds.tracks.$_" => "tracks.$_" } }
4238 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4243 Both producing the following SQL:
4245 SELECT me.artistid, me.name, me.rank, me.charfield,
4246 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4247 genre.genreid, genre.name,
4248 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4251 ON cds.artist = me.artistid
4252 LEFT JOIN genre genre
4253 ON genre.genreid = cds.genreid
4254 LEFT JOIN track tracks
4255 ON tracks.cd = cds.cdid
4256 ORDER BY me.artistid
4258 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4259 the arguments are properly merged and generally do the right thing. For
4260 example, you may want to do the following:
4262 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4263 { 'genre.genreid' => undef },
4265 join => { cds => 'genre' },
4270 Which generates the following SQL:
4272 SELECT me.artistid, me.name, me.rank, me.charfield,
4273 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4276 ON cds.artist = me.artistid
4277 LEFT JOIN genre genre
4278 ON genre.genreid = cds.genreid
4279 WHERE genre.genreid IS NULL
4280 ORDER BY me.artistid
4282 For a more in-depth discussion, see L</PREFETCHING>.
4288 =item Value: $source_alias
4292 Sets the source alias for the query. Normally, this defaults to C<me>, but
4293 nested search queries (sub-SELECTs) might need specific aliases set to
4294 reference inner queries. For example:
4297 ->related_resultset('CDs')
4298 ->related_resultset('Tracks')
4300 'track.id' => { -ident => 'none_search.id' },
4304 my $ids = $self->search({
4307 alias => 'none_search',
4308 group_by => 'none_search.id',
4309 })->get_column('id')->as_query;
4311 $self->search({ id => { -in => $ids } })
4313 This attribute is directly tied to L</current_source_alias>.
4323 Makes the resultset paged and specifies the page to retrieve. Effectively
4324 identical to creating a non-pages resultset and then calling ->page($page)
4327 If L</rows> attribute is not specified it defaults to 10 rows per page.
4329 When you have a paged resultset, L</count> will only return the number
4330 of rows in the page. To get the total, use the L</pager> and call
4331 C<total_entries> on it.
4341 Specifies the maximum number of rows for direct retrieval or the number of
4342 rows per page if the page attribute or method is used.
4348 =item Value: $offset
4352 Specifies the (zero-based) row number for the first row to be returned, or the
4353 of the first row of the first page if paging is used.
4355 =head2 software_limit
4359 =item Value: (0 | 1)
4363 When combined with L</rows> and/or L</offset> the generated SQL will not
4364 include any limit dialect stanzas. Instead the entire result will be selected
4365 as if no limits were specified, and DBIC will perform the limit locally, by
4366 artificially advancing and finishing the resulting L</cursor>.
4368 This is the recommended way of performing resultset limiting when no sane RDBMS
4369 implementation is available (e.g.
4370 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4371 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4377 =item Value: \@columns
4381 A arrayref of columns to group by. Can include columns of joined tables.
4383 group_by => [qw/ column1 column2 ... /]
4389 =item Value: $condition
4393 HAVING is a select statement attribute that is applied between GROUP BY and
4394 ORDER BY. It is applied to the after the grouping calculations have been
4397 having => { 'count_employee' => { '>=', 100 } }
4399 or with an in-place function in which case literal SQL is required:
4401 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4407 =item Value: (0 | 1)
4411 Set to 1 to group by all columns. If the resultset already has a group_by
4412 attribute, this setting is ignored and an appropriate warning is issued.
4418 Adds to the WHERE clause.
4420 # only return rows WHERE deleted IS NULL for all searches
4421 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4423 Can be overridden by passing C<< { where => undef } >> as an attribute
4426 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4432 Set to 1 to cache search results. This prevents extra SQL queries if you
4433 revisit rows in your ResultSet:
4435 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4437 while( my $artist = $resultset->next ) {
4441 $rs->first; # without cache, this would issue a query
4443 By default, searches are not cached.
4445 For more examples of using these attributes, see
4446 L<DBIx::Class::Manual::Cookbook>.
4452 =item Value: ( 'update' | 'shared' | \$scalar )
4456 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4457 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4462 DBIx::Class supports arbitrary related data prefetching from multiple related
4463 sources. Any combination of relationship types and column sets are supported.
4464 If L<collapsing|/collapse> is requested, there is an additional requirement of
4465 selecting enough data to make every individual object uniquely identifiable.
4467 Here are some more involved examples, based on the following relationship map:
4470 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4471 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4472 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4474 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4476 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4480 my $rs = $schema->resultset('Tag')->search(
4489 The initial search results in SQL like the following:
4491 SELECT tag.*, cd.*, artist.* FROM tag
4492 JOIN cd ON tag.cd = cd.cdid
4493 JOIN artist ON cd.artist = artist.artistid
4495 L<DBIx::Class> has no need to go back to the database when we access the
4496 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4499 Simple prefetches will be joined automatically, so there is no need
4500 for a C<join> attribute in the above search.
4502 The L</prefetch> attribute can be used with any of the relationship types
4503 and multiple prefetches can be specified together. Below is a more complex
4504 example that prefetches a CD's artist, its liner notes (if present),
4505 the cover image, the tracks on that CD, and the guests on those
4508 my $rs = $schema->resultset('CD')->search(
4512 { artist => 'record_label'}, # belongs_to => belongs_to
4513 'liner_note', # might_have
4514 'cover_image', # has_one
4515 { tracks => 'guests' }, # has_many => has_many
4520 This will produce SQL like the following:
4522 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4526 ON artist.artistid = me.artistid
4527 JOIN record_label record_label
4528 ON record_label.labelid = artist.labelid
4529 LEFT JOIN track tracks
4530 ON tracks.cdid = me.cdid
4531 LEFT JOIN guest guests
4532 ON guests.trackid = track.trackid
4533 LEFT JOIN liner_notes liner_note
4534 ON liner_note.cdid = me.cdid
4535 JOIN cd_artwork cover_image
4536 ON cover_image.cdid = me.cdid
4539 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4540 C<tracks>, and C<guests> of the CD will all be available through the
4541 relationship accessors without the need for additional queries to the
4546 Prefetch does a lot of deep magic. As such, it may not behave exactly
4547 as you might expect.
4553 Prefetch uses the L</cache> to populate the prefetched relationships. This
4554 may or may not be what you want.
4558 If you specify a condition on a prefetched relationship, ONLY those
4559 rows that match the prefetched condition will be fetched into that relationship.
4560 This means that adding prefetch to a search() B<may alter> what is returned by
4561 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4563 my $artist_rs = $schema->resultset('Artist')->search({
4569 my $count = $artist_rs->first->cds->count;
4571 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4573 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4575 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4577 That cmp_ok() may or may not pass depending on the datasets involved. This
4578 behavior may or may not survive the 0.09 transition.
4582 =head1 DBIC BIND VALUES
4584 Because DBIC may need more information to bind values than just the column name
4585 and value itself, it uses a special format for both passing and receiving bind
4586 values. Each bind value should be composed of an arrayref of
4587 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4593 If present (in any form), this is what is being passed directly to bind_param.
4594 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4595 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4597 If this is specified, all other bind options described below are ignored.
4601 If present, this is used to infer the actual bind attribute by passing to
4602 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4603 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4605 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4606 currently drivers are expected to "Do the Right Thing" when given a common
4607 datatype name. (Not ideal, but that's what we got at this point.)
4611 Currently used to correctly allocate buffers for bind_param_inout().
4612 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4613 or to a sensible value based on the "data_type".
4617 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4618 explicitly specified they are never overriden). Also used by some weird DBDs,
4619 where the column name should be available at bind_param time (e.g. Oracle).
4623 For backwards compatibility and convenience, the following shortcuts are
4626 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4627 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4628 [ undef, $val ] === [ {}, $val ]
4630 =head1 AUTHOR AND CONTRIBUTORS
4632 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4636 You may distribute this code under the same terms as Perl itself.