1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::ResultSetColumn;
8 use Scalar::Util qw/blessed weaken reftype/;
10 use Data::Compare (); # no imports!!! guard against insane architecture
12 # not importing first() as it will clash with our own method
16 # De-duplication in _merge_attr() is disabled, but left in for reference
17 # (the merger is used for other things that ought not to be de-duped)
18 *__HM_DEDUP = sub () { 0 };
28 # this is real - CDBICompat overrides it with insanity
29 # yes, prototype won't matter, but that's for now ;)
32 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
36 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
40 my $users_rs = $schema->resultset('User');
41 while( $user = $users_rs->next) {
42 print $user->username;
45 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
46 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
50 A ResultSet is an object which stores a set of conditions representing
51 a query. It is the backbone of DBIx::Class (i.e. the really
52 important/useful bit).
54 No SQL is executed on the database when a ResultSet is created, it
55 just stores all the conditions needed to create the query.
57 A basic ResultSet representing the data of an entire table is returned
58 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
59 L<Source|DBIx::Class::Manual::Glossary/Source> name.
61 my $users_rs = $schema->resultset('User');
63 A new ResultSet is returned from calling L</search> on an existing
64 ResultSet. The new one will contain all the conditions of the
65 original, plus any new conditions added in the C<search> call.
67 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
68 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
71 The query that the ResultSet represents is B<only> executed against
72 the database when these methods are called:
73 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
75 If a resultset is used in a numeric context it returns the L</count>.
76 However, if it is used in a boolean context it is B<always> true. So if
77 you want to check if a resultset has any results, you must use C<if $rs
80 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
82 If you want to make your custom ResultSet classes with L<Moose>, use a template
85 package MyApp::Schema::ResultSet::User;
88 use namespace::autoclean;
90 extends 'DBIx::Class::ResultSet';
92 sub BUILDARGS { $_[2] }
96 __PACKAGE__->meta->make_immutable;
100 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
101 clash with the regular ResultSet constructor. Alternatively, you can use:
103 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
105 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
106 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
110 =head2 Chaining resultsets
112 Let's say you've got a query that needs to be run to return some data
113 to the user. But, you have an authorization system in place that
114 prevents certain users from seeing certain information. So, you want
115 to construct the basic query in one method, but add constraints to it in
120 my $request = $self->get_request; # Get a request object somehow.
121 my $schema = $self->result_source->schema;
123 my $cd_rs = $schema->resultset('CD')->search({
124 title => $request->param('title'),
125 year => $request->param('year'),
128 $cd_rs = $self->apply_security_policy( $cd_rs );
130 return $cd_rs->all();
133 sub apply_security_policy {
142 =head3 Resolving conditions and attributes
144 When a resultset is chained from another resultset (ie:
145 C<my $new_rs = $old_rs->search(\%extra_cond, \%attrs)>), conditions
146 and attributes with the same keys need resolving.
148 If any of L</columns>, L</select>, L</as> are present, they reset the
149 original selection, and start the selection "clean".
151 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
152 are merged into the existing ones from the original resultset.
154 The L</where> and L</having> attributes, and any search conditions, are
155 merged with an SQL C<AND> to the existing condition from the original
158 All other attributes are overridden by any new ones supplied in the
161 =head2 Multiple queries
163 Since a resultset just defines a query, you can do all sorts of
164 things with it with the same object.
166 # Don't hit the DB yet.
167 my $cd_rs = $schema->resultset('CD')->search({
168 title => 'something',
172 # Each of these hits the DB individually.
173 my $count = $cd_rs->count;
174 my $most_recent = $cd_rs->get_column('date_released')->max();
175 my @records = $cd_rs->all;
177 And it's not just limited to SELECT statements.
183 $cd_rs->create({ artist => 'Fred' });
185 Which is the same as:
187 $schema->resultset('CD')->create({
188 title => 'something',
193 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
201 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
203 =item Return Value: L<$resultset|/search>
207 The resultset constructor. Takes a source object (usually a
208 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
209 L</ATTRIBUTES> below). Does not perform any queries -- these are
210 executed as needed by the other methods.
212 Generally you never construct a resultset manually. Instead you get one
214 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
215 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
218 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
224 If called on an object, proxies to L</new_result> instead, so
226 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
228 will return a CD object, not a ResultSet, and is equivalent to:
230 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
232 Please also keep in mind that many internals call L</new_result> directly,
233 so overloading this method with the idea of intercepting new result object
234 creation B<will not work>. See also warning pertaining to L</create>.
242 return $class->new_result(@_) if ref $class;
244 my ($source, $attrs) = @_;
245 $source = $source->resolve
246 if $source->isa('DBIx::Class::ResultSourceHandle');
248 $attrs = { %{$attrs||{}} };
249 delete @{$attrs}{qw(_related_results_construction)};
251 if ($attrs->{page}) {
252 $attrs->{rows} ||= 10;
255 $attrs->{alias} ||= 'me';
258 result_source => $source,
259 cond => $attrs->{where},
264 # if there is a dark selector, this means we are already in a
265 # chain and the cleanup/sanification was taken care of by
267 $self->_normalize_selection($attrs)
268 unless $attrs->{_dark_selector};
271 $attrs->{result_class} || $source->result_class
281 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
283 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
287 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
288 my $new_rs = $cd_rs->search({ year => 2005 });
290 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
291 # year = 2005 OR year = 2004
293 In list context, C<< ->all() >> is called implicitly on the resultset, thus
294 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
295 To avoid that, use L</search_rs>.
297 If you need to pass in additional attributes but no additional condition,
298 call it as C<search(undef, \%attrs)>.
300 # "SELECT name, artistid FROM $artist_table"
301 my @all_artists = $schema->resultset('Artist')->search(undef, {
302 columns => [qw/name artistid/],
305 For a list of attributes that can be passed to C<search>, see
306 L</ATTRIBUTES>. For more examples of using this function, see
307 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
308 documentation for the first argument, see L<SQL::Abstract>
309 and its extension L<DBIx::Class::SQLMaker>.
311 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
315 Note that L</search> does not process/deflate any of the values passed in the
316 L<SQL::Abstract>-compatible search condition structure. This is unlike other
317 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
318 manually that any value passed to this method will stringify to something the
319 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
320 objects, for more info see:
321 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
327 my $rs = $self->search_rs( @_ );
332 elsif (defined wantarray) {
336 # we can be called by a relationship helper, which in
337 # turn may be called in void context due to some braindead
338 # overload or whatever else the user decided to be clever
339 # at this particular day. Thus limit the exception to
340 # external code calls only
341 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
342 if (caller)[0] !~ /^\QDBIx::Class::/;
352 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
354 =item Return Value: L<$resultset|/search>
358 This method does the same exact thing as search() except it will
359 always return a resultset, even in list context.
366 my $rsrc = $self->result_source;
367 my ($call_cond, $call_attrs);
369 # Special-case handling for (undef, undef) or (undef)
370 # Note that (foo => undef) is valid deprecated syntax
371 @_ = () if not scalar grep { defined $_ } @_;
377 # fish out attrs in the ($condref, $attr) case
378 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
379 ($call_cond, $call_attrs) = @_;
382 $self->throw_exception('Odd number of arguments to search')
386 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
387 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
389 for my $i (0 .. $#_) {
391 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
392 if (! defined $_[$i] or ref $_[$i] ne '');
398 # see if we can keep the cache (no $rs changes)
400 my %safe = (alias => 1, cache => 1);
401 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
404 ref $call_cond eq 'HASH' && ! keys %$call_cond
406 ref $call_cond eq 'ARRAY' && ! @$call_cond
408 $cache = $self->get_cache;
411 my $old_attrs = { %{$self->{attrs}} };
412 my ($old_having, $old_where) = delete @{$old_attrs}{qw(having where)};
414 my $new_attrs = { %$old_attrs };
416 # take care of call attrs (only if anything is changing)
417 if ($call_attrs and keys %$call_attrs) {
419 # copy for _normalize_selection
420 $call_attrs = { %$call_attrs };
422 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
424 # reset the current selector list if new selectors are supplied
425 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
426 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
429 # Normalize the new selector list (operates on the passed-in attr structure)
430 # Need to do it on every chain instead of only once on _resolved_attrs, in
431 # order to allow detection of empty vs partial 'as'
432 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
433 if $old_attrs->{_dark_selector};
434 $self->_normalize_selection ($call_attrs);
436 # start with blind overwriting merge, exclude selector attrs
437 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
438 delete @{$new_attrs}{@selector_attrs};
440 for (@selector_attrs) {
441 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
442 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
445 # older deprecated name, use only if {columns} is not there
446 if (my $c = delete $new_attrs->{cols}) {
447 carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
448 if ($new_attrs->{columns}) {
449 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
452 $new_attrs->{columns} = $c;
457 # join/prefetch use their own crazy merging heuristics
458 foreach my $key (qw/join prefetch/) {
459 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
460 if exists $call_attrs->{$key};
463 # stack binds together
464 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
468 for ($old_where, $call_cond) {
470 $new_attrs->{where} = $self->_stack_cond (
471 $_, $new_attrs->{where}
476 if (defined $old_having) {
477 $new_attrs->{having} = $self->_stack_cond (
478 $old_having, $new_attrs->{having}
482 my $rs = (ref $self)->new($rsrc, $new_attrs);
484 $rs->set_cache($cache) if ($cache);
490 sub _normalize_selection {
491 my ($self, $attrs) = @_;
494 if ( exists $attrs->{include_columns} ) {
495 carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
496 $attrs->{'+columns'} = $self->_merge_attr(
497 $attrs->{'+columns'}, delete $attrs->{include_columns}
501 # columns are always placed first, however
503 # Keep the X vs +X separation until _resolved_attrs time - this allows to
504 # delay the decision on whether to use a default select list ($rsrc->columns)
505 # allowing stuff like the remove_columns helper to work
507 # select/as +select/+as pairs need special handling - the amount of select/as
508 # elements in each pair does *not* have to be equal (think multicolumn
509 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
510 # supplied at all) - try to infer the alias, either from the -as parameter
511 # of the selector spec, or use the parameter whole if it looks like a column
512 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
513 # is ok as well), but make sure no more additions to the 'as' chain take place
514 for my $pref ('', '+') {
516 my ($sel, $as) = map {
517 my $key = "${pref}${_}";
519 my $val = [ ref $attrs->{$key} eq 'ARRAY'
521 : $attrs->{$key} || ()
523 delete $attrs->{$key};
527 if (! @$as and ! @$sel ) {
530 elsif (@$as and ! @$sel) {
531 $self->throw_exception(
532 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
536 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
537 # if any @$as has been supplied we assume the user knows what (s)he is doing
538 # and blindly keep stacking up pieces
539 unless ($attrs->{_dark_selector}) {
542 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
543 push @$as, $_->{-as};
545 # assume any plain no-space, no-parenthesis string to be a column spec
546 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
547 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
550 # if all else fails - raise a flag that no more aliasing will be allowed
552 $attrs->{_dark_selector} = {
554 string => ($dark_sel_dumper ||= do {
555 require Data::Dumper::Concise;
556 Data::Dumper::Concise::DumperObject()->Indent(0);
557 })->Values([$_])->Dump
565 elsif (@$as < @$sel) {
566 $self->throw_exception(
567 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
570 elsif ($pref and $attrs->{_dark_selector}) {
571 $self->throw_exception(
572 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
578 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
579 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
584 my ($self, $left, $right) = @_;
586 # collapse single element top-level conditions
587 # (single pass only, unlikely to need recursion)
588 for ($left, $right) {
589 if (ref $_ eq 'ARRAY') {
597 elsif (ref $_ eq 'HASH') {
598 my ($first, $more) = keys %$_;
601 if (! defined $first) {
605 elsif (! defined $more) {
606 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
609 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
616 # merge hashes with weeding out of duplicates (simple cases only)
617 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
619 # shallow copy to destroy
620 $right = { %$right };
621 for (grep { exists $right->{$_} } keys %$left) {
622 # the use of eq_deeply here is justified - the rhs of an
623 # expression can contain a lot of twisted weird stuff
624 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
627 $right = undef unless keys %$right;
631 if (defined $left xor defined $right) {
632 return defined $left ? $left : $right;
634 elsif (! defined $left) {
638 return { -and => [ $left, $right ] };
642 =head2 search_literal
644 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
645 should only be used in that context. C<search_literal> is a convenience
646 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
647 want to ensure columns are bound correctly, use L</search>.
649 See L<DBIx::Class::Manual::Cookbook/Searching> and
650 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
651 require C<search_literal>.
655 =item Arguments: $sql_fragment, @standalone_bind_values
657 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
661 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
662 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
664 Pass a literal chunk of SQL to be added to the conditional part of the
667 Example of how to use C<search> instead of C<search_literal>
669 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
670 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
675 my ($self, $sql, @bind) = @_;
677 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
680 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
687 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
689 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
693 Finds and returns a single row based on supplied criteria. Takes either a
694 hashref with the same format as L</create> (including inference of foreign
695 keys from related objects), or a list of primary key values in the same
696 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
697 declaration on the L</result_source>.
699 In either case an attempt is made to combine conditions already existing on
700 the resultset with the condition passed to this method.
702 To aid with preparing the correct query for the storage you may supply the
703 C<key> attribute, which is the name of a
704 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
705 unique constraint corresponding to the
706 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
707 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
708 to construct a query that satisfies the named unique constraint fully (
709 non-NULL values for each column member of the constraint) an exception is
712 If no C<key> is specified, the search is carried over all unique constraints
713 which are fully defined by the available condition.
715 If no such constraint is found, C<find> currently defaults to a simple
716 C<< search->(\%column_values) >> which may or may not do what you expect.
717 Note that this fallback behavior may be deprecated in further versions. If
718 you need to search with arbitrary conditions - use L</search>. If the query
719 resulting from this fallback produces more than one row, a warning to the
720 effect is issued, though only the first row is constructed and returned as
723 In addition to C<key>, L</find> recognizes and applies standard
724 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
726 Note that if you have extra concerns about the correctness of the resulting
727 query you need to specify the C<key> attribute and supply the entire condition
728 as an argument to find (since it is not always possible to perform the
729 combination of the resultset condition with the supplied one, especially if
730 the resultset condition contains literal sql).
732 For example, to find a row by its primary key:
734 my $cd = $schema->resultset('CD')->find(5);
736 You can also find a row by a specific unique constraint:
738 my $cd = $schema->resultset('CD')->find(
740 artist => 'Massive Attack',
741 title => 'Mezzanine',
743 { key => 'cd_artist_title' }
746 See also L</find_or_create> and L</update_or_create>.
752 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
754 my $rsrc = $self->result_source;
757 if (exists $attrs->{key}) {
758 $constraint_name = defined $attrs->{key}
760 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
764 # Parse out the condition from input
767 if (ref $_[0] eq 'HASH') {
768 $call_cond = { %{$_[0]} };
771 # if only values are supplied we need to default to 'primary'
772 $constraint_name = 'primary' unless defined $constraint_name;
774 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
776 $self->throw_exception(
777 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
780 $self->throw_exception (
781 'find() expects either a column/value hashref, or a list of values '
782 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
783 ) unless @c_cols == @_;
786 @{$call_cond}{@c_cols} = @_;
790 for my $key (keys %$call_cond) {
792 my $keyref = ref($call_cond->{$key})
794 my $relinfo = $rsrc->relationship_info($key)
796 my $val = delete $call_cond->{$key};
798 next if $keyref eq 'ARRAY'; # has_many for multi_create
800 my $rel_q = $rsrc->_resolve_condition(
801 $relinfo->{cond}, $val, $key, $key
803 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
804 @related{keys %$rel_q} = values %$rel_q;
808 # relationship conditions take precedence (?)
809 @{$call_cond}{keys %related} = values %related;
811 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
813 if (defined $constraint_name) {
814 $final_cond = $self->_qualify_cond_columns (
816 $self->_build_unique_cond (
824 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
825 # This means that we got here after a merger of relationship conditions
826 # in ::Relationship::Base::search_related (the row method), and furthermore
827 # the relationship is of the 'single' type. This means that the condition
828 # provided by the relationship (already attached to $self) is sufficient,
829 # as there can be only one row in the database that would satisfy the
833 # no key was specified - fall down to heuristics mode:
834 # run through all unique queries registered on the resultset, and
835 # 'OR' all qualifying queries together
836 my (@unique_queries, %seen_column_combinations);
837 for my $c_name ($rsrc->unique_constraint_names) {
838 next if $seen_column_combinations{
839 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
842 push @unique_queries, try {
843 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
847 $final_cond = @unique_queries
848 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
849 : $self->_non_unique_find_fallback ($call_cond, $attrs)
853 # Run the query, passing the result_class since it should propagate for find
854 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
855 if ($rs->_resolved_attrs->{collapse}) {
857 carp "Query returned more than one row" if $rs->next;
865 # This is a stop-gap method as agreed during the discussion on find() cleanup:
866 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
868 # It is invoked when find() is called in legacy-mode with insufficiently-unique
869 # condition. It is provided for overrides until a saner way forward is devised
871 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
872 # the road. Please adjust your tests accordingly to catch this situation early
873 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
875 # The method will not be removed without an adequately complete replacement
876 # for strict-mode enforcement
877 sub _non_unique_find_fallback {
878 my ($self, $cond, $attrs) = @_;
880 return $self->_qualify_cond_columns(
882 exists $attrs->{alias}
884 : $self->{attrs}{alias}
889 sub _qualify_cond_columns {
890 my ($self, $cond, $alias) = @_;
892 my %aliased = %$cond;
893 for (keys %aliased) {
894 $aliased{"$alias.$_"} = delete $aliased{$_}
901 sub _build_unique_cond {
902 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
904 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
906 # combination may fail if $self->{cond} is non-trivial
907 my ($final_cond) = try {
908 $self->_merge_with_rscond ($extra_cond)
913 # trim out everything not in $columns
914 $final_cond = { map {
915 exists $final_cond->{$_}
916 ? ( $_ => $final_cond->{$_} )
920 if (my @missing = grep
921 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
924 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
926 join (', ', map { "'$_'" } @missing),
933 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
935 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
937 carp_unique ( sprintf (
938 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
939 . 'values in column(s): %s). This is almost certainly not what you wanted, '
940 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
942 join (', ', map { "'$_'" } @undefs),
949 =head2 search_related
953 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
955 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
959 $new_rs = $cd_rs->search_related('artist', {
963 Searches the specified relationship, optionally specifying a condition and
964 attributes for matching records. See L</ATTRIBUTES> for more information.
966 In list context, C<< ->all() >> is called implicitly on the resultset, thus
967 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
969 See also L</search_related_rs>.
974 return shift->related_resultset(shift)->search(@_);
977 =head2 search_related_rs
979 This method works exactly the same as search_related, except that
980 it guarantees a resultset, even in list context.
984 sub search_related_rs {
985 return shift->related_resultset(shift)->search_rs(@_);
992 =item Arguments: none
994 =item Return Value: L<$cursor|DBIx::Class::Cursor>
998 Returns a storage-driven cursor to the given resultset. See
999 L<DBIx::Class::Cursor> for more information.
1006 return $self->{cursor} ||= do {
1007 my $attrs = { %{$self->_resolved_attrs } };
1008 $self->result_source->storage->select(
1009 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1018 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1020 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1024 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1026 Inflates the first result without creating a cursor if the resultset has
1027 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1030 While this method can take an optional search condition (just like L</search>)
1031 being a fast-code-path it does not recognize search attributes. If you need to
1032 add extra joins or similar, call L</search> and then chain-call L</single> on the
1033 L<DBIx::Class::ResultSet> returned.
1039 As of 0.08100, this method enforces the assumption that the preceding
1040 query returns only one row. If more than one row is returned, you will receive
1043 Query returned more than one row
1045 In this case, you should be using L</next> or L</find> instead, or if you really
1046 know what you are doing, use the L</rows> attribute to explicitly limit the size
1049 This method will also throw an exception if it is called on a resultset prefetching
1050 has_many, as such a prefetch implies fetching multiple rows from the database in
1051 order to assemble the resulting object.
1058 my ($self, $where) = @_;
1060 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1063 my $attrs = { %{$self->_resolved_attrs} };
1065 $self->throw_exception(
1066 'single() can not be used on resultsets collapsing a has_many. Use find( \%cond ) or next() instead'
1067 ) if $attrs->{collapse};
1070 if (defined $attrs->{where}) {
1073 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1074 $where, delete $attrs->{where} ]
1077 $attrs->{where} = $where;
1081 my $data = [ $self->result_source->storage->select_single(
1082 $attrs->{from}, $attrs->{select},
1083 $attrs->{where}, $attrs
1085 return undef unless @$data;
1086 $self->{_stashed_rows} = [ $data ];
1087 $self->_construct_results->[0];
1093 # Recursively collapse the query, accumulating values for each column.
1095 sub _collapse_query {
1096 my ($self, $query, $collapsed) = @_;
1100 if (ref $query eq 'ARRAY') {
1101 foreach my $subquery (@$query) {
1102 next unless ref $subquery; # -or
1103 $collapsed = $self->_collapse_query($subquery, $collapsed);
1106 elsif (ref $query eq 'HASH') {
1107 if (keys %$query and (keys %$query)[0] eq '-and') {
1108 foreach my $subquery (@{$query->{-and}}) {
1109 $collapsed = $self->_collapse_query($subquery, $collapsed);
1113 foreach my $col (keys %$query) {
1114 my $value = $query->{$col};
1115 $collapsed->{$col}{$value}++;
1127 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1129 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1133 my $max_length = $rs->get_column('length')->max;
1135 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1140 my ($self, $column) = @_;
1141 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1149 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1151 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1155 # WHERE title LIKE '%blue%'
1156 $cd_rs = $rs->search_like({ title => '%blue%'});
1158 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1159 that this is simply a convenience method retained for ex Class::DBI users.
1160 You most likely want to use L</search> with specific operators.
1162 For more information, see L<DBIx::Class::Manual::Cookbook>.
1164 This method is deprecated and will be removed in 0.09. Use L</search()>
1165 instead. An example conversion is:
1167 ->search_like({ foo => 'bar' });
1171 ->search({ foo => { like => 'bar' } });
1178 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1179 .' Instead use ->search({ x => { -like => "y%" } })'
1180 .' (note the outer pair of {}s - they are important!)'
1182 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1183 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1184 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1185 return $class->search($query, { %$attrs });
1192 =item Arguments: $first, $last
1194 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1198 Returns a resultset or object list representing a subset of elements from the
1199 resultset slice is called on. Indexes are from 0, i.e., to get the first
1200 three records, call:
1202 my ($one, $two, $three) = $rs->slice(0, 2);
1207 my ($self, $min, $max) = @_;
1208 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1209 $attrs->{offset} = $self->{attrs}{offset} || 0;
1210 $attrs->{offset} += $min;
1211 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1212 return $self->search(undef, $attrs);
1213 #my $slice = (ref $self)->new($self->result_source, $attrs);
1214 #return (wantarray ? $slice->all : $slice);
1221 =item Arguments: none
1223 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1227 Returns the next element in the resultset (C<undef> is there is none).
1229 Can be used to efficiently iterate over records in the resultset:
1231 my $rs = $schema->resultset('CD')->search;
1232 while (my $cd = $rs->next) {
1236 Note that you need to store the resultset object, and call C<next> on it.
1237 Calling C<< resultset('Table')->next >> repeatedly will always return the
1238 first record from the resultset.
1245 if (my $cache = $self->get_cache) {
1246 $self->{all_cache_position} ||= 0;
1247 return $cache->[$self->{all_cache_position}++];
1250 if ($self->{attrs}{cache}) {
1251 delete $self->{pager};
1252 $self->{all_cache_position} = 1;
1253 return ($self->all)[0];
1256 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1258 $self->{_stashed_results} = $self->_construct_results
1261 return shift @{$self->{_stashed_results}};
1264 # Constructs as many results as it can in one pass while respecting
1265 # cursor laziness. Several modes of operation:
1267 # * Always builds everything present in @{$self->{_stashed_rows}}
1268 # * If called with $fetch_all true - pulls everything off the cursor and
1269 # builds all result structures (or objects) in one pass
1270 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1271 # and if the resultset is ordered properly by the left side:
1272 # * Fetches stuff off the cursor until the "master object" changes,
1273 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1275 # * Just fetches, and collapses/constructs everything as if $fetch_all
1276 # was requested (there is no other way to collapse except for an
1278 # * If no collapse is requested - just get the next row, construct and
1280 sub _construct_results {
1281 my ($self, $fetch_all) = @_;
1283 my $rsrc = $self->result_source;
1284 my $attrs = $self->_resolved_attrs;
1289 ! $attrs->{order_by}
1293 my @pcols = $rsrc->primary_columns
1295 # default order for collapsing unless the user asked for something
1296 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
1297 $attrs->{_ordered_for_collapse} = 1;
1298 $attrs->{_order_is_artificial} = 1;
1301 my $cursor = $self->cursor;
1303 # this will be used as both initial raw-row collector AND as a RV of
1304 # _construct_results. Not regrowing the array twice matters a lot...
1305 # a surprising amount actually
1306 my $rows = delete $self->{_stashed_rows};
1308 my $did_fetch_all = $fetch_all;
1311 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1312 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1314 elsif( $attrs->{collapse} ) {
1316 $attrs->{_ordered_for_collapse} = (
1322 ->_main_source_order_by_portion_is_stable($rsrc, $attrs->{order_by}, $attrs->{where})
1324 ) unless defined $attrs->{_ordered_for_collapse};
1326 if (! $attrs->{_ordered_for_collapse}) {
1329 # instead of looping over ->next, use ->all in stealth mode
1330 # *without* calling a ->reset afterwards
1331 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1332 if (! $cursor->{_done}) {
1333 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1334 $cursor->{_done} = 1;
1339 if (! $did_fetch_all and ! @{$rows||[]} ) {
1340 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1341 if (scalar (my @r = $cursor->next) ) {
1346 return undef unless @{$rows||[]};
1348 my @extra_collapser_args;
1349 if ($attrs->{collapse} and ! $did_fetch_all ) {
1351 @extra_collapser_args = (
1352 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1353 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1354 ($self->{_stashed_rows} = []), # where does it stuff excess
1358 # hotspot - skip the setter
1359 my $res_class = $self->_result_class;
1361 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1362 $res_class->can ('inflate_result')
1363 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1366 my $infmap = $attrs->{as};
1369 $self->{_result_inflator}{is_core_row} = ( (
1372 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1373 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1375 $self->{_result_inflator}{is_hri} = ( (
1376 ! $self->{_result_inflator}{is_core_row}
1379 require DBIx::Class::ResultClass::HashRefInflator
1381 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1383 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1386 if (! $attrs->{_related_results_construction}) {
1387 # construct a much simpler array->hash folder for the one-table cases right here
1388 if ($self->{_result_inflator}{is_hri}) {
1389 for my $r (@$rows) {
1390 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1393 # FIXME SUBOPTIMAL this is a very very very hot spot
1394 # while rather optimal we can *still* do much better, by
1395 # building a smarter Row::inflate_result(), and
1396 # switch to feeding it data via a much leaner interface
1398 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1399 # this particular resultset size
1400 elsif (@$rows < 60) {
1401 for my $r (@$rows) {
1402 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1407 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1408 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1412 # Special-case multi-object HRI (we always prune, and there is no $inflator_cref pass)
1413 elsif ($self->{_result_inflator}{is_hri}) {
1415 # $args and $attrs to _mk_row_parser are seperated to delineate what is
1416 # core collapser stuff and what is dbic $rs specific
1417 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1419 inflate_map => $infmap,
1420 collapse => $attrs->{collapse},
1421 premultiplied => $attrs->{_main_source_premultiplied},
1423 prune_null_branches => 1,
1424 }, $attrs) )->($rows, @extra_collapser_args);
1426 # Regular multi-object
1428 my $parser_type = $self->{_result_inflator}{is_core_row} ? 'classic_pruning' : 'classic_nonpruning';
1430 # $args and $attrs to _mk_row_parser are seperated to delineate what is
1431 # core collapser stuff and what is dbic $rs specific
1432 ( $self->{_row_parser}{$parser_type} ||= $rsrc->_mk_row_parser({
1434 inflate_map => $infmap,
1435 collapse => $attrs->{collapse},
1436 premultiplied => $attrs->{_main_source_premultiplied},
1437 prune_null_branches => $self->{_result_inflator}{is_core_row},
1438 }, $attrs) )->($rows, @extra_collapser_args);
1440 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1443 # The @$rows check seems odd at first - why wouldn't we want to warn
1444 # regardless? The issue is things like find() etc, where the user
1445 # *knows* only one result will come back. In these cases the ->all
1446 # is not a pessimization, but rather something we actually want
1448 'Unable to properly collapse has_many results in iterator mode due '
1449 . 'to order criteria - performed an eager cursor slurp underneath. '
1450 . 'Consider using ->all() instead'
1451 ) if ( ! $fetch_all and @$rows > 1 );
1456 =head2 result_source
1460 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1462 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1466 An accessor for the primary ResultSource object from which this ResultSet
1473 =item Arguments: $result_class?
1475 =item Return Value: $result_class
1479 An accessor for the class to use when creating result objects. Defaults to
1480 C<< result_source->result_class >> - which in most cases is the name of the
1481 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1483 Note that changing the result_class will also remove any components
1484 that were originally loaded in the source class via
1485 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1486 in the original source class will not run.
1491 my ($self, $result_class) = @_;
1492 if ($result_class) {
1494 # don't fire this for an object
1495 $self->ensure_class_loaded($result_class)
1496 unless ref($result_class);
1498 if ($self->get_cache) {
1499 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1501 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1502 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1503 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1506 $self->_result_class($result_class);
1508 delete $self->{_result_inflator};
1510 $self->_result_class;
1517 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1519 =item Return Value: $count
1523 Performs an SQL C<COUNT> with the same query as the resultset was built
1524 with to find the number of elements. Passing arguments is equivalent to
1525 C<< $rs->search ($cond, \%attrs)->count >>
1531 return $self->search(@_)->count if @_ and defined $_[0];
1532 return scalar @{ $self->get_cache } if $self->get_cache;
1534 my $attrs = { %{ $self->_resolved_attrs } };
1536 # this is a little optimization - it is faster to do the limit
1537 # adjustments in software, instead of a subquery
1538 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1541 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1542 $crs = $self->_count_subq_rs ($attrs);
1545 $crs = $self->_count_rs ($attrs);
1547 my $count = $crs->next;
1549 $count -= $offset if $offset;
1550 $count = $rows if $rows and $rows < $count;
1551 $count = 0 if ($count < 0);
1560 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1562 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1566 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1567 This can be very handy for subqueries:
1569 ->search( { amount => $some_rs->count_rs->as_query } )
1571 As with regular resultsets the SQL query will be executed only after
1572 the resultset is accessed via L</next> or L</all>. That would return
1573 the same single value obtainable via L</count>.
1579 return $self->search(@_)->count_rs if @_;
1581 # this may look like a lack of abstraction (count() does about the same)
1582 # but in fact an _rs *must* use a subquery for the limits, as the
1583 # software based limiting can not be ported if this $rs is to be used
1584 # in a subquery itself (i.e. ->as_query)
1585 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1586 return $self->_count_subq_rs($self->{_attrs});
1589 return $self->_count_rs($self->{_attrs});
1594 # returns a ResultSetColumn object tied to the count query
1597 my ($self, $attrs) = @_;
1599 my $rsrc = $self->result_source;
1601 my $tmp_attrs = { %$attrs };
1602 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1603 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1605 # overwrite the selector (supplied by the storage)
1606 $rsrc->resultset_class->new($rsrc, {
1608 select => $rsrc->storage->_count_select ($rsrc, $attrs),
1610 })->get_column ('count');
1614 # same as above but uses a subquery
1616 sub _count_subq_rs {
1617 my ($self, $attrs) = @_;
1619 my $rsrc = $self->result_source;
1621 my $sub_attrs = { %$attrs };
1622 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1623 delete @{$sub_attrs}{qw/collapse columns as select order_by for/};
1625 # if we multi-prefetch we group_by something unique, as this is what we would
1626 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1627 if ( $attrs->{collapse} ) {
1628 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1629 $rsrc->_identifying_column_set || $self->throw_exception(
1630 'Unable to construct a unique group_by criteria properly collapsing the '
1631 . 'has_many prefetch before count()'
1636 # Calculate subquery selector
1637 if (my $g = $sub_attrs->{group_by}) {
1639 my $sql_maker = $rsrc->storage->sql_maker;
1641 # necessary as the group_by may refer to aliased functions
1643 for my $sel (@{$attrs->{select}}) {
1644 $sel_index->{$sel->{-as}} = $sel
1645 if (ref $sel eq 'HASH' and $sel->{-as});
1648 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1649 # also look for named aggregates referred in the having clause
1650 # having often contains scalarrefs - thus parse it out entirely
1652 if ($attrs->{having}) {
1653 local $sql_maker->{having_bind};
1654 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1655 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1656 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1657 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1658 # if we don't unset it we screw up retarded but unfortunately working
1659 # 'MAX(foo.bar)' => { '>', 3 }
1660 $sql_maker->{name_sep} = '';
1663 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1665 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1668 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1669 # and if all fails for an utterly naive quoted scalar-with-function
1670 while ($having_sql =~ /
1671 $rquote $sep $lquote (.+?) $rquote
1673 [\s,] \w+ \. (\w+) [\s,]
1675 [\s,] $lquote (.+?) $rquote [\s,]
1677 my $part = $1 || $2 || $3; # one of them matched if we got here
1678 unless ($seen_having{$part}++) {
1685 my $colpiece = $sel_index->{$_} || $_;
1687 # unqualify join-based group_by's. Arcane but possible query
1688 # also horrible horrible hack to alias a column (not a func.)
1689 # (probably need to introduce SQLA syntax)
1690 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1693 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1695 push @{$sub_attrs->{select}}, $colpiece;
1699 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1700 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1703 return $rsrc->resultset_class
1704 ->new ($rsrc, $sub_attrs)
1706 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1707 ->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_results/};
1753 if (my $c = $self->get_cache) {
1757 $self->cursor->reset;
1759 my $objs = $self->_construct_results('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_results/};
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}{qw(group_by _grouped_by_distinct)};
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 @{$attrs->{from}} > 1) {
1842 ($attrs->{from}, $join_classifications) =
1843 $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1845 # any non-pruneable non-local restricting joins imply subq
1846 $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
1849 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1851 (ref $attrs->{from}[0]) ne 'HASH'
1853 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1857 # do we need anything like a subquery?
1858 if (! $needs_subq) {
1859 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1860 # a condition containing 'me' or other table prefixes will not work
1861 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1863 my $sqla = $rsrc->storage->sql_maker;
1864 local $sqla->{_dequalify_idents} = 1;
1865 \[ $sqla->_recurse_where($self->{cond}) ];
1869 # we got this far - means it is time to wrap a subquery
1870 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1872 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1878 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1879 delete $attrs->{$_} for qw/select as collapse/;
1880 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1882 # this will be consumed by the pruner waaaaay down the stack
1883 $attrs->{_force_prune_multiplying_joins} = 1;
1885 my $subrs = (ref $self)->new($rsrc, $attrs);
1887 if (@$idcols == 1) {
1888 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1890 elsif ($storage->_use_multicolumn_in) {
1891 # no syntax for calling this properly yet
1892 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1893 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1894 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1899 # if all else fails - get all primary keys and operate over a ORed set
1900 # wrap in a transaction for consistency
1901 # this is where the group_by/multiplication starts to matter
1905 keys %{ $join_classifications->{multiplying} || {} }
1907 # make sure if there is a supplied group_by it matches the columns compiled above
1908 # perfectly. Anything else can not be sanely executed on most databases so croak
1909 # right then and there
1910 if ($existing_group_by) {
1911 my @current_group_by = map
1912 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1917 join ("\x00", sort @current_group_by)
1919 join ("\x00", sort @{$attrs->{columns}} )
1921 $self->throw_exception (
1922 "You have just attempted a $op operation on a resultset which does group_by"
1923 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1924 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1925 . ' kind of queries. Please retry the operation with a modified group_by or'
1926 . ' without using one at all.'
1931 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1934 $guard = $storage->txn_scope_guard;
1937 for my $row ($subrs->cursor->all) {
1939 { $idcols->[$_] => $row->[$_] }
1946 my $res = $storage->$op (
1948 $op eq 'update' ? $values : (),
1952 $guard->commit if $guard;
1961 =item Arguments: \%values
1963 =item Return Value: $underlying_storage_rv
1967 Sets the specified columns in the resultset to the supplied values in a
1968 single query. Note that this will not run any accessor/set_column/update
1969 triggers, nor will it update any result object instances derived from this
1970 resultset (this includes the contents of the L<resultset cache|/set_cache>
1971 if any). See L</update_all> if you need to execute any on-update
1972 triggers or cascades defined either by you or a
1973 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1975 The return value is a pass through of what the underlying
1976 storage backend returned, and may vary. See L<DBI/execute> for the most
1981 Note that L</update> does not process/deflate any of the values passed in.
1982 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1983 ensure manually that any value passed to this method will stringify to
1984 something the RDBMS knows how to deal with. A notable example is the
1985 handling of L<DateTime> objects, for more info see:
1986 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1991 my ($self, $values) = @_;
1992 $self->throw_exception('Values for update must be a hash')
1993 unless ref $values eq 'HASH';
1995 return $self->_rs_update_delete ('update', $values);
2002 =item Arguments: \%values
2004 =item Return Value: 1
2008 Fetches all objects and updates them one at a time via
2009 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2010 triggers, while L</update> will not.
2015 my ($self, $values) = @_;
2016 $self->throw_exception('Values for update_all must be a hash')
2017 unless ref $values eq 'HASH';
2019 my $guard = $self->result_source->schema->txn_scope_guard;
2020 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2029 =item Arguments: none
2031 =item Return Value: $underlying_storage_rv
2035 Deletes the rows matching this resultset in a single query. Note that this
2036 will not run any delete triggers, nor will it alter the
2037 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2038 derived from this resultset (this includes the contents of the
2039 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2040 execute any on-delete triggers or cascades defined either by you or a
2041 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2043 The return value is a pass through of what the underlying storage backend
2044 returned, and may vary. See L<DBI/execute> for the most common case.
2050 $self->throw_exception('delete does not accept any arguments')
2053 return $self->_rs_update_delete ('delete');
2060 =item Arguments: none
2062 =item Return Value: 1
2066 Fetches all objects and deletes them one at a time via
2067 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2068 triggers, while L</delete> will not.
2074 $self->throw_exception('delete_all does not accept any arguments')
2077 my $guard = $self->result_source->schema->txn_scope_guard;
2078 $_->delete for $self->all;
2087 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2089 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2093 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2100 The context of this method call has an important effect on what is
2101 submitted to storage. In void context data is fed directly to fastpath
2102 insertion routines provided by the underlying storage (most often
2103 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2104 L<insert|DBIx::Class::Row/insert> calls on the
2105 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2106 augmentation of these methods provided by components. For example if you
2107 are using something like L<DBIx::Class::UUIDColumns> to create primary
2108 keys for you, you will find that your PKs are empty. In this case you
2109 will have to explicitly force scalar or list context in order to create
2114 In non-void (scalar or list) context, this method is simply a wrapper
2115 for L</create>. Depending on list or scalar context either a list of
2116 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2117 containing these objects is returned.
2119 When supplying data in "arrayref of arrayrefs" invocation style, the
2120 first element should be a list of column names and each subsequent
2121 element should be a data value in the earlier specified column order.
2124 $Arstist_rs->populate([
2125 [ qw( artistid name ) ],
2126 [ 100, 'A Formally Unknown Singer' ],
2127 [ 101, 'A singer that jumped the shark two albums ago' ],
2128 [ 102, 'An actually cool singer' ],
2131 For the arrayref of hashrefs style each hashref should be a structure
2132 suitable for passing to L</create>. Multi-create is also permitted with
2135 $schema->resultset("Artist")->populate([
2136 { artistid => 4, name => 'Manufactured Crap', cds => [
2137 { title => 'My First CD', year => 2006 },
2138 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2141 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2142 { title => 'My parents sold me to a record company', year => 2005 },
2143 { title => 'Why Am I So Ugly?', year => 2006 },
2144 { title => 'I Got Surgery and am now Popular', year => 2007 }
2149 If you attempt a void-context multi-create as in the example above (each
2150 Artist also has the related list of CDs), and B<do not> supply the
2151 necessary autoinc foreign key information, this method will proxy to the
2152 less efficient L</create>, and then throw the Result objects away. In this
2153 case there are obviously no benefits to using this method over L</create>.
2160 # cruft placed in standalone method
2161 my $data = $self->_normalize_populate_args(@_);
2163 return unless @$data;
2165 if(defined wantarray) {
2166 my @created = map { $self->create($_) } @$data;
2167 return wantarray ? @created : \@created;
2170 my $first = $data->[0];
2172 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2173 # it relationship data
2174 my (@rels, @columns);
2175 my $rsrc = $self->result_source;
2176 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2177 for (keys %$first) {
2178 my $ref = ref $first->{$_};
2179 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2185 my @pks = $rsrc->primary_columns;
2187 ## do the belongs_to relationships
2188 foreach my $index (0..$#$data) {
2190 # delegate to create() for any dataset without primary keys with specified relationships
2191 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2193 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2194 my @ret = $self->populate($data);
2200 foreach my $rel (@rels) {
2201 next unless ref $data->[$index]->{$rel} eq "HASH";
2202 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2203 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2204 my $related = $result->result_source->_resolve_condition(
2205 $reverse_relinfo->{cond},
2211 delete $data->[$index]->{$rel};
2212 $data->[$index] = {%{$data->[$index]}, %$related};
2214 push @columns, keys %$related if $index == 0;
2218 ## inherit the data locked in the conditions of the resultset
2219 my ($rs_data) = $self->_merge_with_rscond({});
2220 delete @{$rs_data}{@columns};
2222 ## do bulk insert on current row
2223 $rsrc->storage->insert_bulk(
2225 [@columns, keys %$rs_data],
2226 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2229 ## do the has_many relationships
2230 foreach my $item (@$data) {
2234 foreach my $rel (@rels) {
2235 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2237 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2239 my $child = $main_row->$rel;
2241 my $related = $child->result_source->_resolve_condition(
2242 $rels->{$rel}{cond},
2248 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2249 my @populate = map { {%$_, %$related} } @rows_to_add;
2251 $child->populate( \@populate );
2258 # populate() argumnets went over several incarnations
2259 # What we ultimately support is AoH
2260 sub _normalize_populate_args {
2261 my ($self, $arg) = @_;
2263 if (ref $arg eq 'ARRAY') {
2267 elsif (ref $arg->[0] eq 'HASH') {
2270 elsif (ref $arg->[0] eq 'ARRAY') {
2272 my @colnames = @{$arg->[0]};
2273 foreach my $values (@{$arg}[1 .. $#$arg]) {
2274 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2280 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2287 =item Arguments: none
2289 =item Return Value: L<$pager|Data::Page>
2293 Returns a L<Data::Page> object for the current resultset. Only makes
2294 sense for queries with a C<page> attribute.
2296 To get the full count of entries for a paged resultset, call
2297 C<total_entries> on the L<Data::Page> object.
2304 return $self->{pager} if $self->{pager};
2306 my $attrs = $self->{attrs};
2307 if (!defined $attrs->{page}) {
2308 $self->throw_exception("Can't create pager for non-paged rs");
2310 elsif ($attrs->{page} <= 0) {
2311 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2313 $attrs->{rows} ||= 10;
2315 # throw away the paging flags and re-run the count (possibly
2316 # with a subselect) to get the real total count
2317 my $count_attrs = { %$attrs };
2318 delete @{$count_attrs}{qw/rows offset page pager/};
2320 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2322 require DBIx::Class::ResultSet::Pager;
2323 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2324 sub { $total_rs->count }, #lazy-get the total
2326 $self->{attrs}{page},
2334 =item Arguments: $page_number
2336 =item Return Value: L<$resultset|/search>
2340 Returns a resultset for the $page_number page of the resultset on which page
2341 is called, where each page contains a number of rows equal to the 'rows'
2342 attribute set on the resultset (10 by default).
2347 my ($self, $page) = @_;
2348 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2355 =item Arguments: \%col_data
2357 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2361 Creates a new result object in the resultset's result class and returns
2362 it. The row is not inserted into the database at this point, call
2363 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2364 will tell you whether the result object has been inserted or not.
2366 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2371 my ($self, $values) = @_;
2373 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2376 $self->throw_exception( "new_result expects a hashref" )
2377 unless (ref $values eq 'HASH');
2379 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2381 my $new = $self->result_class->new({
2383 ( @$cols_from_relations
2384 ? (-cols_from_relations => $cols_from_relations)
2387 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2391 reftype($new) eq 'HASH'
2397 carp_unique (sprintf (
2398 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2399 $self->result_class,
2406 # _merge_with_rscond
2408 # Takes a simple hash of K/V data and returns its copy merged with the
2409 # condition already present on the resultset. Additionally returns an
2410 # arrayref of value/condition names, which were inferred from related
2411 # objects (this is needed for in-memory related objects)
2412 sub _merge_with_rscond {
2413 my ($self, $data) = @_;
2415 my (%new_data, @cols_from_relations);
2417 my $alias = $self->{attrs}{alias};
2419 if (! defined $self->{cond}) {
2420 # just massage $data below
2422 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2423 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2424 @cols_from_relations = keys %new_data;
2426 elsif (ref $self->{cond} ne 'HASH') {
2427 $self->throw_exception(
2428 "Can't abstract implicit construct, resultset condition not a hash"
2432 # precendence must be given to passed values over values inherited from
2433 # the cond, so the order here is important.
2434 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2435 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2437 while ( my($col, $value) = each %implied ) {
2438 my $vref = ref $value;
2444 (keys %$value)[0] eq '='
2446 $new_data{$col} = $value->{'='};
2448 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2449 $new_data{$col} = $value;
2456 %{ $self->_remove_alias($data, $alias) },
2459 return (\%new_data, \@cols_from_relations);
2462 # _has_resolved_attr
2464 # determines if the resultset defines at least one
2465 # of the attributes supplied
2467 # used to determine if a subquery is neccessary
2469 # supports some virtual attributes:
2471 # This will scan for any joins being present on the resultset.
2472 # It is not a mere key-search but a deep inspection of {from}
2475 sub _has_resolved_attr {
2476 my ($self, @attr_names) = @_;
2478 my $attrs = $self->_resolved_attrs;
2482 for my $n (@attr_names) {
2483 if (grep { $n eq $_ } (qw/-join/) ) {
2484 $extra_checks{$n}++;
2488 my $attr = $attrs->{$n};
2490 next if not defined $attr;
2492 if (ref $attr eq 'HASH') {
2493 return 1 if keys %$attr;
2495 elsif (ref $attr eq 'ARRAY') {
2503 # a resolved join is expressed as a multi-level from
2505 $extra_checks{-join}
2507 ref $attrs->{from} eq 'ARRAY'
2509 @{$attrs->{from}} > 1
2517 # Recursively collapse the condition.
2519 sub _collapse_cond {
2520 my ($self, $cond, $collapsed) = @_;
2524 if (ref $cond eq 'ARRAY') {
2525 foreach my $subcond (@$cond) {
2526 next unless ref $subcond; # -or
2527 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2530 elsif (ref $cond eq 'HASH') {
2531 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2532 foreach my $subcond (@{$cond->{-and}}) {
2533 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2537 foreach my $col (keys %$cond) {
2538 my $value = $cond->{$col};
2539 $collapsed->{$col} = $value;
2549 # Remove the specified alias from the specified query hash. A copy is made so
2550 # the original query is not modified.
2553 my ($self, $query, $alias) = @_;
2555 my %orig = %{ $query || {} };
2558 foreach my $key (keys %orig) {
2560 $unaliased{$key} = $orig{$key};
2563 $unaliased{$1} = $orig{$key}
2564 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2574 =item Arguments: none
2576 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2580 Returns the SQL query and bind vars associated with the invocant.
2582 This is generally used as the RHS for a subquery.
2589 my $attrs = { %{ $self->_resolved_attrs } };
2591 $self->result_source->storage->_select_args_to_query (
2592 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2600 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2602 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2606 my $artist = $schema->resultset('Artist')->find_or_new(
2607 { artist => 'fred' }, { key => 'artists' });
2609 $cd->cd_to_producer->find_or_new({ producer => $producer },
2610 { key => 'primary });
2612 Find an existing record from this resultset using L</find>. if none exists,
2613 instantiate a new result object and return it. The object will not be saved
2614 into your storage until you call L<DBIx::Class::Row/insert> on it.
2616 You most likely want this method when looking for existing rows using a unique
2617 constraint that is not the primary key, or looking for related rows.
2619 If you want objects to be saved immediately, use L</find_or_create> instead.
2621 B<Note>: Make sure to read the documentation of L</find> and understand the
2622 significance of the C<key> attribute, as its lack may skew your search, and
2623 subsequently result in spurious new objects.
2625 B<Note>: Take care when using C<find_or_new> with a table having
2626 columns with default values that you intend to be automatically
2627 supplied by the database (e.g. an auto_increment primary key column).
2628 In normal usage, the value of such columns should NOT be included at
2629 all in the call to C<find_or_new>, even when set to C<undef>.
2635 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2636 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2637 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2640 return $self->new_result($hash);
2647 =item Arguments: \%col_data
2649 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2653 Attempt to create a single new row or a row with multiple related rows
2654 in the table represented by the resultset (and related tables). This
2655 will not check for duplicate rows before inserting, use
2656 L</find_or_create> to do that.
2658 To create one row for this resultset, pass a hashref of key/value
2659 pairs representing the columns of the table and the values you wish to
2660 store. If the appropriate relationships are set up, foreign key fields
2661 can also be passed an object representing the foreign row, and the
2662 value will be set to its primary key.
2664 To create related objects, pass a hashref of related-object column values
2665 B<keyed on the relationship name>. If the relationship is of type C<multi>
2666 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2667 The process will correctly identify columns holding foreign keys, and will
2668 transparently populate them from the keys of the corresponding relation.
2669 This can be applied recursively, and will work correctly for a structure
2670 with an arbitrary depth and width, as long as the relationships actually
2671 exists and the correct column data has been supplied.
2673 Instead of hashrefs of plain related data (key/value pairs), you may
2674 also pass new or inserted objects. New objects (not inserted yet, see
2675 L</new_result>), will be inserted into their appropriate tables.
2677 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2679 Example of creating a new row.
2681 $person_rs->create({
2682 name=>"Some Person",
2683 email=>"somebody@someplace.com"
2686 Example of creating a new row and also creating rows in a related C<has_many>
2687 or C<has_one> resultset. Note Arrayref.
2690 { artistid => 4, name => 'Manufactured Crap', cds => [
2691 { title => 'My First CD', year => 2006 },
2692 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2697 Example of creating a new row and also creating a row in a related
2698 C<belongs_to> resultset. Note Hashref.
2701 title=>"Music for Silly Walks",
2704 name=>"Silly Musician",
2712 When subclassing ResultSet never attempt to override this method. Since
2713 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2714 lot of the internals simply never call it, so your override will be
2715 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2716 or L<DBIx::Class::Row/insert> depending on how early in the
2717 L</create> process you need to intervene. See also warning pertaining to
2725 my ($self, $col_data) = @_;
2726 $self->throw_exception( "create needs a hashref" )
2727 unless ref $col_data eq 'HASH';
2728 return $self->new_result($col_data)->insert;
2731 =head2 find_or_create
2735 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2737 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2741 $cd->cd_to_producer->find_or_create({ producer => $producer },
2742 { key => 'primary' });
2744 Tries to find a record based on its primary key or unique constraints; if none
2745 is found, creates one and returns that instead.
2747 my $cd = $schema->resultset('CD')->find_or_create({
2749 artist => 'Massive Attack',
2750 title => 'Mezzanine',
2754 Also takes an optional C<key> attribute, to search by a specific key or unique
2755 constraint. For example:
2757 my $cd = $schema->resultset('CD')->find_or_create(
2759 artist => 'Massive Attack',
2760 title => 'Mezzanine',
2762 { key => 'cd_artist_title' }
2765 B<Note>: Make sure to read the documentation of L</find> and understand the
2766 significance of the C<key> attribute, as its lack may skew your search, and
2767 subsequently result in spurious row creation.
2769 B<Note>: Because find_or_create() reads from the database and then
2770 possibly inserts based on the result, this method is subject to a race
2771 condition. Another process could create a record in the table after
2772 the find has completed and before the create has started. To avoid
2773 this problem, use find_or_create() inside a transaction.
2775 B<Note>: Take care when using C<find_or_create> with a table having
2776 columns with default values that you intend to be automatically
2777 supplied by the database (e.g. an auto_increment primary key column).
2778 In normal usage, the value of such columns should NOT be included at
2779 all in the call to C<find_or_create>, even when set to C<undef>.
2781 See also L</find> and L</update_or_create>. For information on how to declare
2782 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2784 If you need to know if an existing row was found or a new one created use
2785 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2786 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2789 my $cd = $schema->resultset('CD')->find_or_new({
2791 artist => 'Massive Attack',
2792 title => 'Mezzanine',
2796 if( !$cd->in_storage ) {
2803 sub find_or_create {
2805 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2806 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2807 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2810 return $self->create($hash);
2813 =head2 update_or_create
2817 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2819 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2823 $resultset->update_or_create({ col => $val, ... });
2825 Like L</find_or_create>, but if a row is found it is immediately updated via
2826 C<< $found_row->update (\%col_data) >>.
2829 Takes an optional C<key> attribute to search on a specific unique constraint.
2832 # In your application
2833 my $cd = $schema->resultset('CD')->update_or_create(
2835 artist => 'Massive Attack',
2836 title => 'Mezzanine',
2839 { key => 'cd_artist_title' }
2842 $cd->cd_to_producer->update_or_create({
2843 producer => $producer,
2849 B<Note>: Make sure to read the documentation of L</find> and understand the
2850 significance of the C<key> attribute, as its lack may skew your search, and
2851 subsequently result in spurious row creation.
2853 B<Note>: Take care when using C<update_or_create> with a table having
2854 columns with default values that you intend to be automatically
2855 supplied by the database (e.g. an auto_increment primary key column).
2856 In normal usage, the value of such columns should NOT be included at
2857 all in the call to C<update_or_create>, even when set to C<undef>.
2859 See also L</find> and L</find_or_create>. For information on how to declare
2860 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2862 If you need to know if an existing row was updated or a new one created use
2863 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2864 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2869 sub update_or_create {
2871 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2872 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2874 my $row = $self->find($cond, $attrs);
2876 $row->update($cond);
2880 return $self->create($cond);
2883 =head2 update_or_new
2887 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2889 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2893 $resultset->update_or_new({ col => $val, ... });
2895 Like L</find_or_new> but if a row is found it is immediately updated via
2896 C<< $found_row->update (\%col_data) >>.
2900 # In your application
2901 my $cd = $schema->resultset('CD')->update_or_new(
2903 artist => 'Massive Attack',
2904 title => 'Mezzanine',
2907 { key => 'cd_artist_title' }
2910 if ($cd->in_storage) {
2911 # the cd was updated
2914 # the cd is not yet in the database, let's insert it
2918 B<Note>: Make sure to read the documentation of L</find> and understand the
2919 significance of the C<key> attribute, as its lack may skew your search, and
2920 subsequently result in spurious new objects.
2922 B<Note>: Take care when using C<update_or_new> with a table having
2923 columns with default values that you intend to be automatically
2924 supplied by the database (e.g. an auto_increment primary key column).
2925 In normal usage, the value of such columns should NOT be included at
2926 all in the call to C<update_or_new>, even when set to C<undef>.
2928 See also L</find>, L</find_or_create> and L</find_or_new>.
2934 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2935 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2937 my $row = $self->find( $cond, $attrs );
2938 if ( defined $row ) {
2939 $row->update($cond);
2943 return $self->new_result($cond);
2950 =item Arguments: none
2952 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2956 Gets the contents of the cache for the resultset, if the cache is set.
2958 The cache is populated either by using the L</prefetch> attribute to
2959 L</search> or by calling L</set_cache>.
2971 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2973 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2977 Sets the contents of the cache for the resultset. Expects an arrayref
2978 of objects of the same class as those produced by the resultset. Note that
2979 if the cache is set, the resultset will return the cached objects rather
2980 than re-querying the database even if the cache attr is not set.
2982 The contents of the cache can also be populated by using the
2983 L</prefetch> attribute to L</search>.
2988 my ( $self, $data ) = @_;
2989 $self->throw_exception("set_cache requires an arrayref")
2990 if defined($data) && (ref $data ne 'ARRAY');
2991 $self->{all_cache} = $data;
2998 =item Arguments: none
3000 =item Return Value: undef
3004 Clears the cache for the resultset.
3009 shift->set_cache(undef);
3016 =item Arguments: none
3018 =item Return Value: true, if the resultset has been paginated
3026 return !!$self->{attrs}{page};
3033 =item Arguments: none
3035 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3043 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3046 =head2 related_resultset
3050 =item Arguments: $rel_name
3052 =item Return Value: L<$resultset|/search>
3056 Returns a related resultset for the supplied relationship name.
3058 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3062 sub related_resultset {
3063 my ($self, $rel) = @_;
3065 return $self->{related_resultsets}{$rel}
3066 if defined $self->{related_resultsets}{$rel};
3068 return $self->{related_resultsets}{$rel} = do {
3069 my $rsrc = $self->result_source;
3070 my $rel_info = $rsrc->relationship_info($rel);
3072 $self->throw_exception(
3073 "search_related: result source '" . $rsrc->source_name .
3074 "' has no such relationship $rel")
3077 my $attrs = $self->_chain_relationship($rel);
3079 my $join_count = $attrs->{seen_join}{$rel};
3081 my $alias = $self->result_source->storage
3082 ->relname_to_table_alias($rel, $join_count);
3084 # since this is search_related, and we already slid the select window inwards
3085 # (the select/as attrs were deleted in the beginning), we need to flip all
3086 # left joins to inner, so we get the expected results
3087 # read the comment on top of the actual function to see what this does
3088 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3091 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3092 delete @{$attrs}{qw(result_class alias)};
3096 if (my $cache = $self->get_cache) {
3097 $related_cache = [ map
3098 { @{$_->related_resultset($rel)->get_cache||[]} }
3103 my $rel_source = $rsrc->related_source($rel);
3107 # The reason we do this now instead of passing the alias to the
3108 # search_rs below is that if you wrap/overload resultset on the
3109 # source you need to know what alias it's -going- to have for things
3110 # to work sanely (e.g. RestrictWithObject wants to be able to add
3111 # extra query restrictions, and these may need to be $alias.)
3113 my $rel_attrs = $rel_source->resultset_attributes;
3114 local $rel_attrs->{alias} = $alias;
3116 $rel_source->resultset
3120 where => $attrs->{where},
3123 $new->set_cache($related_cache) if $related_cache;
3128 =head2 current_source_alias
3132 =item Arguments: none
3134 =item Return Value: $source_alias
3138 Returns the current table alias for the result source this resultset is built
3139 on, that will be used in the SQL query. Usually it is C<me>.
3141 Currently the source alias that refers to the result set returned by a
3142 L</search>/L</find> family method depends on how you got to the resultset: it's
3143 C<me> by default, but eg. L</search_related> aliases it to the related result
3144 source name (and keeps C<me> referring to the original result set). The long
3145 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3146 (and make this method unnecessary).
3148 Thus it's currently necessary to use this method in predefined queries (see
3149 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3150 source alias of the current result set:
3152 # in a result set class
3154 my ($self, $user) = @_;
3156 my $me = $self->current_source_alias;
3158 return $self->search({
3159 "$me.modified" => $user->id,
3165 sub current_source_alias {
3166 return (shift->{attrs} || {})->{alias} || 'me';
3169 =head2 as_subselect_rs
3173 =item Arguments: none
3175 =item Return Value: L<$resultset|/search>
3179 Act as a barrier to SQL symbols. The resultset provided will be made into a
3180 "virtual view" by including it as a subquery within the from clause. From this
3181 point on, any joined tables are inaccessible to ->search on the resultset (as if
3182 it were simply where-filtered without joins). For example:
3184 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3186 # 'x' now pollutes the query namespace
3188 # So the following works as expected
3189 my $ok_rs = $rs->search({'x.other' => 1});
3191 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3192 # def) we look for one row with contradictory terms and join in another table
3193 # (aliased 'x_2') which we never use
3194 my $broken_rs = $rs->search({'x.name' => 'def'});
3196 my $rs2 = $rs->as_subselect_rs;
3198 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3199 my $not_joined_rs = $rs2->search({'x.other' => 1});
3201 # works as expected: finds a 'table' row related to two x rows (abc and def)
3202 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3204 Another example of when one might use this would be to select a subset of
3205 columns in a group by clause:
3207 my $rs = $schema->resultset('Bar')->search(undef, {
3208 group_by => [qw{ id foo_id baz_id }],
3209 })->as_subselect_rs->search(undef, {
3210 columns => [qw{ id foo_id }]
3213 In the above example normally columns would have to be equal to the group by,
3214 but because we isolated the group by into a subselect the above works.
3218 sub as_subselect_rs {
3221 my $attrs = $self->_resolved_attrs;
3223 my $fresh_rs = (ref $self)->new (
3224 $self->result_source
3227 # these pieces will be locked in the subquery
3228 delete $fresh_rs->{cond};
3229 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3231 return $fresh_rs->search( {}, {
3233 $attrs->{alias} => $self->as_query,
3234 -alias => $attrs->{alias},
3235 -rsrc => $self->result_source,
3237 alias => $attrs->{alias},
3241 # This code is called by search_related, and makes sure there
3242 # is clear separation between the joins before, during, and
3243 # after the relationship. This information is needed later
3244 # in order to properly resolve prefetch aliases (any alias
3245 # with a relation_chain_depth less than the depth of the
3246 # current prefetch is not considered)
3248 # The increments happen twice per join. An even number means a
3249 # relationship specified via a search_related, whereas an odd
3250 # number indicates a join/prefetch added via attributes
3252 # Also this code will wrap the current resultset (the one we
3253 # chain to) in a subselect IFF it contains limiting attributes
3254 sub _chain_relationship {
3255 my ($self, $rel) = @_;
3256 my $source = $self->result_source;
3257 my $attrs = { %{$self->{attrs}||{}} };
3259 # we need to take the prefetch the attrs into account before we
3260 # ->_resolve_join as otherwise they get lost - captainL
3261 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3263 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3265 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3268 my @force_subq_attrs = qw/offset rows group_by having/;
3271 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3273 $self->_has_resolved_attr (@force_subq_attrs)
3275 # Nuke the prefetch (if any) before the new $rs attrs
3276 # are resolved (prefetch is useless - we are wrapping
3277 # a subquery anyway).
3278 my $rs_copy = $self->search;
3279 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3280 $rs_copy->{attrs}{join},
3281 delete $rs_copy->{attrs}{prefetch},
3286 -alias => $attrs->{alias},
3287 $attrs->{alias} => $rs_copy->as_query,
3289 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3290 $seen->{-relation_chain_depth} = 0;
3292 elsif ($attrs->{from}) { #shallow copy suffices
3293 $from = [ @{$attrs->{from}} ];
3298 -alias => $attrs->{alias},
3299 $attrs->{alias} => $source->from,
3303 my $jpath = ($seen->{-relation_chain_depth})
3304 ? $from->[-1][0]{-join_path}
3307 my @requested_joins = $source->_resolve_join(
3314 push @$from, @requested_joins;
3316 $seen->{-relation_chain_depth}++;
3318 # if $self already had a join/prefetch specified on it, the requested
3319 # $rel might very well be already included. What we do in this case
3320 # is effectively a no-op (except that we bump up the chain_depth on
3321 # the join in question so we could tell it *is* the search_related)
3324 # we consider the last one thus reverse
3325 for my $j (reverse @requested_joins) {
3326 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3327 if ($rel eq $last_j) {
3328 $j->[0]{-relation_chain_depth}++;
3334 unless ($already_joined) {
3335 push @$from, $source->_resolve_join(
3343 $seen->{-relation_chain_depth}++;
3345 return {%$attrs, from => $from, seen_join => $seen};
3348 sub _resolved_attrs {
3350 return $self->{_attrs} if $self->{_attrs};
3352 my $attrs = { %{ $self->{attrs} || {} } };
3353 my $source = $self->result_source;
3354 my $alias = $attrs->{alias};
3356 # default selection list
3357 $attrs->{columns} = [ $source->columns ]
3358 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3360 # merge selectors together
3361 for (qw/columns select as/) {
3362 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3363 if $attrs->{$_} or $attrs->{"+$_"};
3366 # disassemble columns
3368 if (my $cols = delete $attrs->{columns}) {
3369 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3370 if (ref $c eq 'HASH') {
3371 for my $as (sort keys %$c) {
3372 push @sel, $c->{$as};
3383 # when trying to weed off duplicates later do not go past this point -
3384 # everything added from here on is unbalanced "anyone's guess" stuff
3385 my $dedup_stop_idx = $#as;
3387 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3389 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3390 if $attrs->{select};
3392 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3393 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3395 # disqualify all $alias.col as-bits (inflate-map mandated)
3396 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3398 # de-duplicate the result (remove *identical* select/as pairs)
3399 # and also die on duplicate {as} pointing to different {select}s
3400 # not using a c-style for as the condition is prone to shrinkage
3403 while ($i <= $dedup_stop_idx) {
3404 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3409 elsif ($seen->{$as[$i]}++) {
3410 $self->throw_exception(
3411 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3419 $attrs->{select} = \@sel;
3420 $attrs->{as} = \@as;
3422 $attrs->{from} ||= [{
3424 -alias => $self->{attrs}{alias},
3425 $self->{attrs}{alias} => $source->from,
3428 if ( $attrs->{join} || $attrs->{prefetch} ) {
3430 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3431 if ref $attrs->{from} ne 'ARRAY';
3433 my $join = (delete $attrs->{join}) || {};
3435 if ( defined $attrs->{prefetch} ) {
3436 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3439 $attrs->{from} = # have to copy here to avoid corrupting the original
3441 @{ $attrs->{from} },
3442 $source->_resolve_join(
3445 { %{ $attrs->{seen_join} || {} } },
3446 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3447 ? $attrs->{from}[-1][0]{-join_path}
3454 if ( defined $attrs->{order_by} ) {
3455 $attrs->{order_by} = (
3456 ref( $attrs->{order_by} ) eq 'ARRAY'
3457 ? [ @{ $attrs->{order_by} } ]
3458 : [ $attrs->{order_by} || () ]
3462 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3463 $attrs->{group_by} = [ $attrs->{group_by} ];
3466 # generate the distinct induced group_by early, as prefetch will be carried via a
3467 # subquery (since a group_by is present)
3468 if (delete $attrs->{distinct}) {
3469 if ($attrs->{group_by}) {
3470 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3473 $attrs->{_grouped_by_distinct} = 1;
3474 # distinct affects only the main selection part, not what prefetch may
3476 $attrs->{group_by} = $source->storage->_group_over_selection($attrs);
3480 # generate selections based on the prefetch helper
3482 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3483 if defined $attrs->{prefetch};
3487 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3488 if $attrs->{_dark_selector};
3490 $attrs->{collapse} = 1;
3492 # this is a separate structure (we don't look in {from} directly)
3493 # as the resolver needs to shift things off the lists to work
3494 # properly (identical-prefetches on different branches)
3496 if (ref $attrs->{from} eq 'ARRAY') {
3498 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3500 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3501 next unless $j->[0]{-alias};
3502 next unless $j->[0]{-join_path};
3503 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3505 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3508 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3509 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3513 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3515 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3516 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3519 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3520 $attrs->{_related_results_construction} = 1;
3523 $attrs->{collapse} = 0;
3526 # run through the resulting joinstructure (starting from our current slot)
3527 # and unset collapse if proven unnesessary
3529 # also while we are at it find out if the current root source has
3530 # been premultiplied by previous related_source chaining
3532 # this allows to predict whether a root object with all other relation
3533 # data set to NULL is in fact unique
3534 if ($attrs->{collapse}) {
3536 if (ref $attrs->{from} eq 'ARRAY') {
3538 if (@{$attrs->{from}} == 1) {
3539 # no joins - no collapse
3540 $attrs->{collapse} = 0;
3543 # find where our table-spec starts
3544 my @fromlist = @{$attrs->{from}};
3546 my $t = shift @fromlist;
3549 # me vs join from-spec distinction - a ref means non-root
3550 if (ref $t eq 'ARRAY') {
3552 $is_multi ||= ! $t->{-is_single};
3554 last if ($t->{-alias} && $t->{-alias} eq $alias);
3555 $attrs->{_main_source_premultiplied} ||= $is_multi;
3558 # no non-singles remaining, nor any premultiplication - nothing to collapse
3560 ! $attrs->{_main_source_premultiplied}
3562 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3564 $attrs->{collapse} = 0;
3570 # if we can not analyze the from - err on the side of safety
3571 $attrs->{_main_source_premultiplied} = 1;
3575 # if both page and offset are specified, produce a combined offset
3576 # even though it doesn't make much sense, this is what pre 081xx has
3578 if (my $page = delete $attrs->{page}) {
3580 ($attrs->{rows} * ($page - 1))
3582 ($attrs->{offset} || 0)
3586 return $self->{_attrs} = $attrs;
3590 my ($self, $attr) = @_;
3592 if (ref $attr eq 'HASH') {
3593 return $self->_rollout_hash($attr);
3594 } elsif (ref $attr eq 'ARRAY') {
3595 return $self->_rollout_array($attr);
3601 sub _rollout_array {
3602 my ($self, $attr) = @_;
3605 foreach my $element (@{$attr}) {
3606 if (ref $element eq 'HASH') {
3607 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3608 } elsif (ref $element eq 'ARRAY') {
3609 # XXX - should probably recurse here
3610 push( @rolled_array, @{$self->_rollout_array($element)} );
3612 push( @rolled_array, $element );
3615 return \@rolled_array;
3619 my ($self, $attr) = @_;
3622 foreach my $key (keys %{$attr}) {
3623 push( @rolled_array, { $key => $attr->{$key} } );
3625 return \@rolled_array;
3628 sub _calculate_score {
3629 my ($self, $a, $b) = @_;
3631 if (defined $a xor defined $b) {
3634 elsif (not defined $a) {
3638 if (ref $b eq 'HASH') {
3639 my ($b_key) = keys %{$b};
3640 if (ref $a eq 'HASH') {
3641 my ($a_key) = keys %{$a};
3642 if ($a_key eq $b_key) {
3643 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3648 return ($a eq $b_key) ? 1 : 0;
3651 if (ref $a eq 'HASH') {
3652 my ($a_key) = keys %{$a};
3653 return ($b eq $a_key) ? 1 : 0;
3655 return ($b eq $a) ? 1 : 0;
3660 sub _merge_joinpref_attr {
3661 my ($self, $orig, $import) = @_;
3663 return $import unless defined($orig);
3664 return $orig unless defined($import);
3666 $orig = $self->_rollout_attr($orig);
3667 $import = $self->_rollout_attr($import);
3670 foreach my $import_element ( @{$import} ) {
3671 # find best candidate from $orig to merge $b_element into
3672 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3673 foreach my $orig_element ( @{$orig} ) {
3674 my $score = $self->_calculate_score( $orig_element, $import_element );
3675 if ($score > $best_candidate->{score}) {
3676 $best_candidate->{position} = $position;
3677 $best_candidate->{score} = $score;
3681 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3682 $import_key = '' if not defined $import_key;
3684 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3685 push( @{$orig}, $import_element );
3687 my $orig_best = $orig->[$best_candidate->{position}];
3688 # merge orig_best and b_element together and replace original with merged
3689 if (ref $orig_best ne 'HASH') {
3690 $orig->[$best_candidate->{position}] = $import_element;
3691 } elsif (ref $import_element eq 'HASH') {
3692 my ($key) = keys %{$orig_best};
3693 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3696 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3699 return @$orig ? $orig : ();
3707 require Hash::Merge;
3708 my $hm = Hash::Merge->new;
3710 $hm->specify_behavior({
3713 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3715 if ($defl xor $defr) {
3716 return [ $defl ? $_[0] : $_[1] ];
3721 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3725 return [$_[0], $_[1]];
3729 return $_[1] if !defined $_[0];
3730 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3731 return [$_[0], @{$_[1]}]
3734 return [] if !defined $_[0] and !keys %{$_[1]};
3735 return [ $_[1] ] if !defined $_[0];
3736 return [ $_[0] ] if !keys %{$_[1]};
3737 return [$_[0], $_[1]]
3742 return $_[0] if !defined $_[1];
3743 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3744 return [@{$_[0]}, $_[1]]
3747 my @ret = @{$_[0]} or return $_[1];
3748 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3749 my %idx = map { $_ => 1 } @ret;
3750 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3754 return [ $_[1] ] if ! @{$_[0]};
3755 return $_[0] if !keys %{$_[1]};
3756 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3757 return [ @{$_[0]}, $_[1] ];
3762 return [] if !keys %{$_[0]} and !defined $_[1];
3763 return [ $_[0] ] if !defined $_[1];
3764 return [ $_[1] ] if !keys %{$_[0]};
3765 return [$_[0], $_[1]]
3768 return [] if !keys %{$_[0]} and !@{$_[1]};
3769 return [ $_[0] ] if !@{$_[1]};
3770 return $_[1] if !keys %{$_[0]};
3771 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3772 return [ $_[0], @{$_[1]} ];
3775 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3776 return [ $_[0] ] if !keys %{$_[1]};
3777 return [ $_[1] ] if !keys %{$_[0]};
3778 return [ $_[0] ] if $_[0] eq $_[1];
3779 return [ $_[0], $_[1] ];
3782 } => 'DBIC_RS_ATTR_MERGER');
3786 return $hm->merge ($_[1], $_[2]);
3790 sub STORABLE_freeze {
3791 my ($self, $cloning) = @_;
3792 my $to_serialize = { %$self };
3794 # A cursor in progress can't be serialized (and would make little sense anyway)
3795 # the parser can be regenerated (and can't be serialized)
3796 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3798 # nor is it sensical to store a not-yet-fired-count pager
3799 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3800 delete $to_serialize->{pager};
3803 Storable::nfreeze($to_serialize);
3806 # need this hook for symmetry
3808 my ($self, $cloning, $serialized) = @_;
3810 %$self = %{ Storable::thaw($serialized) };
3816 =head2 throw_exception
3818 See L<DBIx::Class::Schema/throw_exception> for details.
3822 sub throw_exception {
3825 if (ref $self and my $rsrc = $self->result_source) {
3826 $rsrc->throw_exception(@_)
3829 DBIx::Class::Exception->throw(@_);
3837 # XXX: FIXME: Attributes docs need clearing up
3841 Attributes are used to refine a ResultSet in various ways when
3842 searching for data. They can be passed to any method which takes an
3843 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3846 Default attributes can be set on the result class using
3847 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3848 the CAVEATS on that feature before using it!)
3850 These are in no particular order:
3856 =item Value: ( $order_by | \@order_by | \%order_by )
3860 Which column(s) to order the results by.
3862 [The full list of suitable values is documented in
3863 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3866 If a single column name, or an arrayref of names is supplied, the
3867 argument is passed through directly to SQL. The hashref syntax allows
3868 for connection-agnostic specification of ordering direction:
3870 For descending order:
3872 order_by => { -desc => [qw/col1 col2 col3/] }
3874 For explicit ascending order:
3876 order_by => { -asc => 'col' }
3878 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3879 supported, although you are strongly encouraged to use the hashref
3880 syntax as outlined above.
3886 =item Value: \@columns | \%columns | $column
3890 Shortcut to request a particular set of columns to be retrieved. Each
3891 column spec may be a string (a table column name), or a hash (in which
3892 case the key is the C<as> value, and the value is used as the C<select>
3893 expression). Adds C<me.> onto the start of any column without a C<.> in
3894 it and sets C<select> from that, then auto-populates C<as> from
3895 C<select> as normal. (You may also use the C<cols> attribute, as in
3896 earlier versions of DBIC, but this is deprecated.)
3898 Essentially C<columns> does the same as L</select> and L</as>.
3900 columns => [ 'foo', { bar => 'baz' } ]
3904 select => [qw/foo baz/],
3911 =item Value: \@columns
3915 Indicates additional columns to be selected from storage. Works the same as
3916 L</columns> but adds columns to the selection. (You may also use the
3917 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3918 deprecated). For example:-
3920 $schema->resultset('CD')->search(undef, {
3921 '+columns' => ['artist.name'],
3925 would return all CDs and include a 'name' column to the information
3926 passed to object inflation. Note that the 'artist' is the name of the
3927 column (or relationship) accessor, and 'name' is the name of the column
3928 accessor in the related table.
3930 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3931 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3932 unary plus operator before it.
3934 =head2 include_columns
3938 =item Value: \@columns
3942 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3948 =item Value: \@select_columns
3952 Indicates which columns should be selected from the storage. You can use
3953 column names, or in the case of RDBMS back ends, function or stored procedure
3956 $rs = $schema->resultset('Employee')->search(undef, {
3959 { count => 'employeeid' },
3960 { max => { length => 'name' }, -as => 'longest_name' }
3965 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3967 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3968 use L</select>, to instruct DBIx::Class how to store the result of the column.
3969 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3970 identifier aliasing. You can however alias a function, so you can use it in
3971 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3972 attribute> supplied as shown in the example above.
3974 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3975 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3976 unary plus operator before it.
3982 Indicates additional columns to be selected from storage. Works the same as
3983 L</select> but adds columns to the default selection, instead of specifying
3992 =item Value: \@inflation_names
3996 Indicates column names for object inflation. That is L</as> indicates the
3997 slot name in which the column value will be stored within the
3998 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
3999 identifier by the C<get_column> method (or via the object accessor B<if one
4000 with the same name already exists>) as shown below. The L</as> attribute has
4001 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4003 $rs = $schema->resultset('Employee')->search(undef, {
4006 { count => 'employeeid' },
4007 { max => { length => 'name' }, -as => 'longest_name' }
4016 If the object against which the search is performed already has an accessor
4017 matching a column name specified in C<as>, the value can be retrieved using
4018 the accessor as normal:
4020 my $name = $employee->name();
4022 If on the other hand an accessor does not exist in the object, you need to
4023 use C<get_column> instead:
4025 my $employee_count = $employee->get_column('employee_count');
4027 You can create your own accessors if required - see
4028 L<DBIx::Class::Manual::Cookbook> for details.
4034 Indicates additional column names for those added via L</+select>. See L</as>.
4042 =item Value: ($rel_name | \@rel_names | \%rel_names)
4046 Contains a list of relationships that should be joined for this query. For
4049 # Get CDs by Nine Inch Nails
4050 my $rs = $schema->resultset('CD')->search(
4051 { 'artist.name' => 'Nine Inch Nails' },
4052 { join => 'artist' }
4055 Can also contain a hash reference to refer to the other relation's relations.
4058 package MyApp::Schema::Track;
4059 use base qw/DBIx::Class/;
4060 __PACKAGE__->table('track');
4061 __PACKAGE__->add_columns(qw/trackid cd position title/);
4062 __PACKAGE__->set_primary_key('trackid');
4063 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4066 # In your application
4067 my $rs = $schema->resultset('Artist')->search(
4068 { 'track.title' => 'Teardrop' },
4070 join => { cd => 'track' },
4071 order_by => 'artist.name',
4075 You need to use the relationship (not the table) name in conditions,
4076 because they are aliased as such. The current table is aliased as "me", so
4077 you need to use me.column_name in order to avoid ambiguity. For example:
4079 # Get CDs from 1984 with a 'Foo' track
4080 my $rs = $schema->resultset('CD')->search(
4083 'tracks.name' => 'Foo'
4085 { join => 'tracks' }
4088 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4089 similarly for a third time). For e.g.
4091 my $rs = $schema->resultset('Artist')->search({
4092 'cds.title' => 'Down to Earth',
4093 'cds_2.title' => 'Popular',
4095 join => [ qw/cds cds/ ],
4098 will return a set of all artists that have both a cd with title 'Down
4099 to Earth' and a cd with title 'Popular'.
4101 If you want to fetch related objects from other tables as well, see L</prefetch>
4104 NOTE: An internal join-chain pruner will discard certain joins while
4105 constructing the actual SQL query, as long as the joins in question do not
4106 affect the retrieved result. This for example includes 1:1 left joins
4107 that are not part of the restriction specification (WHERE/HAVING) nor are
4108 a part of the query selection.
4110 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4116 =item Value: (0 | 1)
4120 When set to a true value, indicates that any rows fetched from joined has_many
4121 relationships are to be aggregated into the corresponding "parent" object. For
4122 example, the resultset:
4124 my $rs = $schema->resultset('CD')->search({}, {
4125 '+columns' => [ qw/ tracks.title tracks.position / ],
4130 While executing the following query:
4132 SELECT me.*, tracks.title, tracks.position
4134 LEFT JOIN track tracks
4135 ON tracks.cdid = me.cdid
4137 Will return only as many objects as there are rows in the CD source, even
4138 though the result of the query may span many rows. Each of these CD objects
4139 will in turn have multiple "Track" objects hidden behind the has_many
4140 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4141 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4142 product"), with each CD object containing exactly one of all fetched Track data.
4144 When a collapse is requested on a non-ordered resultset, an order by some
4145 unique part of the main source (the left-most table) is inserted automatically.
4146 This is done so that the resultset is allowed to be "lazy" - calling
4147 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4148 object with all of its related data.
4150 If an L</order_by> is already declared, and orders the resultset in a way that
4151 makes collapsing as described above impossible (e.g. C<< ORDER BY
4152 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4153 switch to "eager" mode and slurp the entire resultset before consturcting the
4154 first object returned by L</next>.
4156 Setting this attribute on a resultset that does not join any has_many
4157 relations is a no-op.
4159 For a more in-depth discussion, see L</PREFETCHING>.
4165 =item Value: ($rel_name | \@rel_names | \%rel_names)
4169 This attribute is a shorthand for specifying a L</join> spec, adding all
4170 columns from the joined related sources as L</+columns> and setting
4171 L</collapse> to a true value. For example, the following two queries are
4174 my $rs = $schema->resultset('Artist')->search({}, {
4175 prefetch => { cds => ['genre', 'tracks' ] },
4180 my $rs = $schema->resultset('Artist')->search({}, {
4181 join => { cds => ['genre', 'tracks' ] },
4185 { +{ "cds.$_" => "cds.$_" } }
4186 $schema->source('Artist')->related_source('cds')->columns
4189 { +{ "cds.genre.$_" => "genre.$_" } }
4190 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4193 { +{ "cds.tracks.$_" => "tracks.$_" } }
4194 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4199 Both producing the following SQL:
4201 SELECT me.artistid, me.name, me.rank, me.charfield,
4202 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4203 genre.genreid, genre.name,
4204 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4207 ON cds.artist = me.artistid
4208 LEFT JOIN genre genre
4209 ON genre.genreid = cds.genreid
4210 LEFT JOIN track tracks
4211 ON tracks.cd = cds.cdid
4212 ORDER BY me.artistid
4214 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4215 the arguments are properly merged and generally do the right thing. For
4216 example, you may want to do the following:
4218 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4219 { 'genre.genreid' => undef },
4221 join => { cds => 'genre' },
4226 Which generates the following SQL:
4228 SELECT me.artistid, me.name, me.rank, me.charfield,
4229 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4232 ON cds.artist = me.artistid
4233 LEFT JOIN genre genre
4234 ON genre.genreid = cds.genreid
4235 WHERE genre.genreid IS NULL
4236 ORDER BY me.artistid
4238 For a more in-depth discussion, see L</PREFETCHING>.
4244 =item Value: $source_alias
4248 Sets the source alias for the query. Normally, this defaults to C<me>, but
4249 nested search queries (sub-SELECTs) might need specific aliases set to
4250 reference inner queries. For example:
4253 ->related_resultset('CDs')
4254 ->related_resultset('Tracks')
4256 'track.id' => { -ident => 'none_search.id' },
4260 my $ids = $self->search({
4263 alias => 'none_search',
4264 group_by => 'none_search.id',
4265 })->get_column('id')->as_query;
4267 $self->search({ id => { -in => $ids } })
4269 This attribute is directly tied to L</current_source_alias>.
4279 Makes the resultset paged and specifies the page to retrieve. Effectively
4280 identical to creating a non-pages resultset and then calling ->page($page)
4283 If L</rows> attribute is not specified it defaults to 10 rows per page.
4285 When you have a paged resultset, L</count> will only return the number
4286 of rows in the page. To get the total, use the L</pager> and call
4287 C<total_entries> on it.
4297 Specifies the maximum number of rows for direct retrieval or the number of
4298 rows per page if the page attribute or method is used.
4304 =item Value: $offset
4308 Specifies the (zero-based) row number for the first row to be returned, or the
4309 of the first row of the first page if paging is used.
4311 =head2 software_limit
4315 =item Value: (0 | 1)
4319 When combined with L</rows> and/or L</offset> the generated SQL will not
4320 include any limit dialect stanzas. Instead the entire result will be selected
4321 as if no limits were specified, and DBIC will perform the limit locally, by
4322 artificially advancing and finishing the resulting L</cursor>.
4324 This is the recommended way of performing resultset limiting when no sane RDBMS
4325 implementation is available (e.g.
4326 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4327 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4333 =item Value: \@columns
4337 A arrayref of columns to group by. Can include columns of joined tables.
4339 group_by => [qw/ column1 column2 ... /]
4345 =item Value: $condition
4349 HAVING is a select statement attribute that is applied between GROUP BY and
4350 ORDER BY. It is applied to the after the grouping calculations have been
4353 having => { 'count_employee' => { '>=', 100 } }
4355 or with an in-place function in which case literal SQL is required:
4357 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4363 =item Value: (0 | 1)
4367 Set to 1 to group by all columns. If the resultset already has a group_by
4368 attribute, this setting is ignored and an appropriate warning is issued.
4374 Adds to the WHERE clause.
4376 # only return rows WHERE deleted IS NULL for all searches
4377 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4379 Can be overridden by passing C<< { where => undef } >> as an attribute
4382 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4388 Set to 1 to cache search results. This prevents extra SQL queries if you
4389 revisit rows in your ResultSet:
4391 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4393 while( my $artist = $resultset->next ) {
4397 $rs->first; # without cache, this would issue a query
4399 By default, searches are not cached.
4401 For more examples of using these attributes, see
4402 L<DBIx::Class::Manual::Cookbook>.
4408 =item Value: ( 'update' | 'shared' | \$scalar )
4412 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4413 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4418 DBIx::Class supports arbitrary related data prefetching from multiple related
4419 sources. Any combination of relationship types and column sets are supported.
4420 If L<collapsing|/collapse> is requested, there is an additional requirement of
4421 selecting enough data to make every individual object uniquely identifiable.
4423 Here are some more involved examples, based on the following relationship map:
4426 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4427 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4428 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4430 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4432 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4436 my $rs = $schema->resultset('Tag')->search(
4445 The initial search results in SQL like the following:
4447 SELECT tag.*, cd.*, artist.* FROM tag
4448 JOIN cd ON tag.cd = cd.cdid
4449 JOIN artist ON cd.artist = artist.artistid
4451 L<DBIx::Class> has no need to go back to the database when we access the
4452 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4455 Simple prefetches will be joined automatically, so there is no need
4456 for a C<join> attribute in the above search.
4458 The L</prefetch> attribute can be used with any of the relationship types
4459 and multiple prefetches can be specified together. Below is a more complex
4460 example that prefetches a CD's artist, its liner notes (if present),
4461 the cover image, the tracks on that CD, and the guests on those
4464 my $rs = $schema->resultset('CD')->search(
4468 { artist => 'record_label'}, # belongs_to => belongs_to
4469 'liner_note', # might_have
4470 'cover_image', # has_one
4471 { tracks => 'guests' }, # has_many => has_many
4476 This will produce SQL like the following:
4478 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4482 ON artist.artistid = me.artistid
4483 JOIN record_label record_label
4484 ON record_label.labelid = artist.labelid
4485 LEFT JOIN track tracks
4486 ON tracks.cdid = me.cdid
4487 LEFT JOIN guest guests
4488 ON guests.trackid = track.trackid
4489 LEFT JOIN liner_notes liner_note
4490 ON liner_note.cdid = me.cdid
4491 JOIN cd_artwork cover_image
4492 ON cover_image.cdid = me.cdid
4495 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4496 C<tracks>, and C<guests> of the CD will all be available through the
4497 relationship accessors without the need for additional queries to the
4502 Prefetch does a lot of deep magic. As such, it may not behave exactly
4503 as you might expect.
4509 Prefetch uses the L</cache> to populate the prefetched relationships. This
4510 may or may not be what you want.
4514 If you specify a condition on a prefetched relationship, ONLY those
4515 rows that match the prefetched condition will be fetched into that relationship.
4516 This means that adding prefetch to a search() B<may alter> what is returned by
4517 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4519 my $artist_rs = $schema->resultset('Artist')->search({
4525 my $count = $artist_rs->first->cds->count;
4527 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4529 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4531 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4533 That cmp_ok() may or may not pass depending on the datasets involved. In other
4534 words the C<WHERE> condition would apply to the entire dataset, just like
4535 it would in regular SQL. If you want to add a condition only to the "right side"
4536 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4537 condition|DBIx::Class::Relationship::Base/condition>
4541 =head1 DBIC BIND VALUES
4543 Because DBIC may need more information to bind values than just the column name
4544 and value itself, it uses a special format for both passing and receiving bind
4545 values. Each bind value should be composed of an arrayref of
4546 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4552 If present (in any form), this is what is being passed directly to bind_param.
4553 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4554 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4556 If this is specified, all other bind options described below are ignored.
4560 If present, this is used to infer the actual bind attribute by passing to
4561 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4562 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4564 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4565 currently drivers are expected to "Do the Right Thing" when given a common
4566 datatype name. (Not ideal, but that's what we got at this point.)
4570 Currently used to correctly allocate buffers for bind_param_inout().
4571 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4572 or to a sensible value based on the "data_type".
4576 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4577 explicitly specified they are never overriden). Also used by some weird DBDs,
4578 where the column name should be available at bind_param time (e.g. Oracle).
4582 For backwards compatibility and convenience, the following shortcuts are
4585 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4586 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4587 [ undef, $val ] === [ {}, $val ]
4589 =head1 AUTHOR AND CONTRIBUTORS
4591 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4595 You may distribute this code under the same terms as Perl itself.