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');
247 $attrs = { %{$attrs||{}} };
249 if ($attrs->{page}) {
250 $attrs->{rows} ||= 10;
253 $attrs->{alias} ||= 'me';
256 result_source => $source,
257 cond => $attrs->{where},
262 # if there is a dark selector, this means we are already in a
263 # chain and the cleanup/sanification was taken care of by
265 $self->_normalize_selection($attrs)
266 unless $attrs->{_dark_selector};
269 $attrs->{result_class} || $source->result_class
279 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
281 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
285 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
286 my $new_rs = $cd_rs->search({ year => 2005 });
288 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
289 # year = 2005 OR year = 2004
291 In list context, C<< ->all() >> is called implicitly on the resultset, thus
292 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
293 To avoid that, use L</search_rs>.
295 If you need to pass in additional attributes but no additional condition,
296 call it as C<search(undef, \%attrs)>.
298 # "SELECT name, artistid FROM $artist_table"
299 my @all_artists = $schema->resultset('Artist')->search(undef, {
300 columns => [qw/name artistid/],
303 For a list of attributes that can be passed to C<search>, see
304 L</ATTRIBUTES>. For more examples of using this function, see
305 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
306 documentation for the first argument, see L<SQL::Abstract>
307 and its extension L<DBIx::Class::SQLMaker>.
309 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
313 Note that L</search> does not process/deflate any of the values passed in the
314 L<SQL::Abstract>-compatible search condition structure. This is unlike other
315 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
316 manually that any value passed to this method will stringify to something the
317 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
318 objects, for more info see:
319 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
325 my $rs = $self->search_rs( @_ );
330 elsif (defined wantarray) {
334 # we can be called by a relationship helper, which in
335 # turn may be called in void context due to some braindead
336 # overload or whatever else the user decided to be clever
337 # at this particular day. Thus limit the exception to
338 # external code calls only
339 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
340 if (caller)[0] !~ /^\QDBIx::Class::/;
350 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
352 =item Return Value: L<$resultset|/search>
356 This method does the same exact thing as search() except it will
357 always return a resultset, even in list context.
364 my $rsrc = $self->result_source;
365 my ($call_cond, $call_attrs);
367 # Special-case handling for (undef, undef) or (undef)
368 # Note that (foo => undef) is valid deprecated syntax
369 @_ = () if not scalar grep { defined $_ } @_;
375 # fish out attrs in the ($condref, $attr) case
376 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
377 ($call_cond, $call_attrs) = @_;
380 $self->throw_exception('Odd number of arguments to search')
384 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
385 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
387 for my $i (0 .. $#_) {
389 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
390 if (! defined $_[$i] or ref $_[$i] ne '');
396 # see if we can keep the cache (no $rs changes)
398 my %safe = (alias => 1, cache => 1);
399 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
402 ref $call_cond eq 'HASH' && ! keys %$call_cond
404 ref $call_cond eq 'ARRAY' && ! @$call_cond
406 $cache = $self->get_cache;
409 my $old_attrs = { %{$self->{attrs}} };
410 my $old_having = delete $old_attrs->{having};
411 my $old_where = delete $old_attrs->{where};
413 my $new_attrs = { %$old_attrs };
415 # take care of call attrs (only if anything is changing)
416 if ($call_attrs and keys %$call_attrs) {
418 # copy for _normalize_selection
419 $call_attrs = { %$call_attrs };
421 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
423 # reset the current selector list if new selectors are supplied
424 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
425 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
428 # Normalize the new selector list (operates on the passed-in attr structure)
429 # Need to do it on every chain instead of only once on _resolved_attrs, in
430 # order to allow detection of empty vs partial 'as'
431 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
432 if $old_attrs->{_dark_selector};
433 $self->_normalize_selection ($call_attrs);
435 # start with blind overwriting merge, exclude selector attrs
436 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
437 delete @{$new_attrs}{@selector_attrs};
439 for (@selector_attrs) {
440 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
441 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
444 # older deprecated name, use only if {columns} is not there
445 if (my $c = delete $new_attrs->{cols}) {
446 if ($new_attrs->{columns}) {
447 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
450 $new_attrs->{columns} = $c;
455 # join/prefetch use their own crazy merging heuristics
456 foreach my $key (qw/join prefetch/) {
457 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
458 if exists $call_attrs->{$key};
461 # stack binds together
462 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
466 for ($old_where, $call_cond) {
468 $new_attrs->{where} = $self->_stack_cond (
469 $_, $new_attrs->{where}
474 if (defined $old_having) {
475 $new_attrs->{having} = $self->_stack_cond (
476 $old_having, $new_attrs->{having}
480 my $rs = (ref $self)->new($rsrc, $new_attrs);
482 $rs->set_cache($cache) if ($cache);
488 sub _normalize_selection {
489 my ($self, $attrs) = @_;
492 $attrs->{'+columns'} = $self->_merge_attr($attrs->{'+columns'}, delete $attrs->{include_columns})
493 if exists $attrs->{include_columns};
495 # columns are always placed first, however
497 # Keep the X vs +X separation until _resolved_attrs time - this allows to
498 # delay the decision on whether to use a default select list ($rsrc->columns)
499 # allowing stuff like the remove_columns helper to work
501 # select/as +select/+as pairs need special handling - the amount of select/as
502 # elements in each pair does *not* have to be equal (think multicolumn
503 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
504 # supplied at all) - try to infer the alias, either from the -as parameter
505 # of the selector spec, or use the parameter whole if it looks like a column
506 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
507 # is ok as well), but make sure no more additions to the 'as' chain take place
508 for my $pref ('', '+') {
510 my ($sel, $as) = map {
511 my $key = "${pref}${_}";
513 my $val = [ ref $attrs->{$key} eq 'ARRAY'
515 : $attrs->{$key} || ()
517 delete $attrs->{$key};
521 if (! @$as and ! @$sel ) {
524 elsif (@$as and ! @$sel) {
525 $self->throw_exception(
526 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
530 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
531 # if any @$as has been supplied we assume the user knows what (s)he is doing
532 # and blindly keep stacking up pieces
533 unless ($attrs->{_dark_selector}) {
536 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
537 push @$as, $_->{-as};
539 # assume any plain no-space, no-parenthesis string to be a column spec
540 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
541 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
544 # if all else fails - raise a flag that no more aliasing will be allowed
546 $attrs->{_dark_selector} = {
548 string => ($dark_sel_dumper ||= do {
549 require Data::Dumper::Concise;
550 Data::Dumper::Concise::DumperObject()->Indent(0);
551 })->Values([$_])->Dump
559 elsif (@$as < @$sel) {
560 $self->throw_exception(
561 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
564 elsif ($pref and $attrs->{_dark_selector}) {
565 $self->throw_exception(
566 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
572 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
573 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
578 my ($self, $left, $right) = @_;
580 # collapse single element top-level conditions
581 # (single pass only, unlikely to need recursion)
582 for ($left, $right) {
583 if (ref $_ eq 'ARRAY') {
591 elsif (ref $_ eq 'HASH') {
592 my ($first, $more) = keys %$_;
595 if (! defined $first) {
599 elsif (! defined $more) {
600 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
603 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
610 # merge hashes with weeding out of duplicates (simple cases only)
611 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
613 # shallow copy to destroy
614 $right = { %$right };
615 for (grep { exists $right->{$_} } keys %$left) {
616 # the use of eq_deeply here is justified - the rhs of an
617 # expression can contain a lot of twisted weird stuff
618 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
621 $right = undef unless keys %$right;
625 if (defined $left xor defined $right) {
626 return defined $left ? $left : $right;
628 elsif (! defined $left) {
632 return { -and => [ $left, $right ] };
636 =head2 search_literal
638 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
639 should only be used in that context. C<search_literal> is a convenience
640 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
641 want to ensure columns are bound correctly, use L</search>.
643 See L<DBIx::Class::Manual::Cookbook/Searching> and
644 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
645 require C<search_literal>.
649 =item Arguments: $sql_fragment, @standalone_bind_values
651 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
655 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
656 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
658 Pass a literal chunk of SQL to be added to the conditional part of the
661 Example of how to use C<search> instead of C<search_literal>
663 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
664 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
669 my ($self, $sql, @bind) = @_;
671 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
674 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
681 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
683 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
687 Finds and returns a single row based on supplied criteria. Takes either a
688 hashref with the same format as L</create> (including inference of foreign
689 keys from related objects), or a list of primary key values in the same
690 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
691 declaration on the L</result_source>.
693 In either case an attempt is made to combine conditions already existing on
694 the resultset with the condition passed to this method.
696 To aid with preparing the correct query for the storage you may supply the
697 C<key> attribute, which is the name of a
698 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
699 unique constraint corresponding to the
700 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
701 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
702 to construct a query that satisfies the named unique constraint fully (
703 non-NULL values for each column member of the constraint) an exception is
706 If no C<key> is specified, the search is carried over all unique constraints
707 which are fully defined by the available condition.
709 If no such constraint is found, C<find> currently defaults to a simple
710 C<< search->(\%column_values) >> which may or may not do what you expect.
711 Note that this fallback behavior may be deprecated in further versions. If
712 you need to search with arbitrary conditions - use L</search>. If the query
713 resulting from this fallback produces more than one row, a warning to the
714 effect is issued, though only the first row is constructed and returned as
717 In addition to C<key>, L</find> recognizes and applies standard
718 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
720 Note that if you have extra concerns about the correctness of the resulting
721 query you need to specify the C<key> attribute and supply the entire condition
722 as an argument to find (since it is not always possible to perform the
723 combination of the resultset condition with the supplied one, especially if
724 the resultset condition contains literal sql).
726 For example, to find a row by its primary key:
728 my $cd = $schema->resultset('CD')->find(5);
730 You can also find a row by a specific unique constraint:
732 my $cd = $schema->resultset('CD')->find(
734 artist => 'Massive Attack',
735 title => 'Mezzanine',
737 { key => 'cd_artist_title' }
740 See also L</find_or_create> and L</update_or_create>.
746 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
748 my $rsrc = $self->result_source;
751 if (exists $attrs->{key}) {
752 $constraint_name = defined $attrs->{key}
754 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
758 # Parse out the condition from input
761 if (ref $_[0] eq 'HASH') {
762 $call_cond = { %{$_[0]} };
765 # if only values are supplied we need to default to 'primary'
766 $constraint_name = 'primary' unless defined $constraint_name;
768 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
770 $self->throw_exception(
771 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
774 $self->throw_exception (
775 'find() expects either a column/value hashref, or a list of values '
776 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
777 ) unless @c_cols == @_;
780 @{$call_cond}{@c_cols} = @_;
784 for my $key (keys %$call_cond) {
786 my $keyref = ref($call_cond->{$key})
788 my $relinfo = $rsrc->relationship_info($key)
790 my $val = delete $call_cond->{$key};
792 next if $keyref eq 'ARRAY'; # has_many for multi_create
794 my $rel_q = $rsrc->_resolve_condition(
795 $relinfo->{cond}, $val, $key, $key
797 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
798 @related{keys %$rel_q} = values %$rel_q;
802 # relationship conditions take precedence (?)
803 @{$call_cond}{keys %related} = values %related;
805 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
807 if (defined $constraint_name) {
808 $final_cond = $self->_qualify_cond_columns (
810 $self->_build_unique_cond (
818 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
819 # This means that we got here after a merger of relationship conditions
820 # in ::Relationship::Base::search_related (the row method), and furthermore
821 # the relationship is of the 'single' type. This means that the condition
822 # provided by the relationship (already attached to $self) is sufficient,
823 # as there can be only one row in the database that would satisfy the
827 # no key was specified - fall down to heuristics mode:
828 # run through all unique queries registered on the resultset, and
829 # 'OR' all qualifying queries together
830 my (@unique_queries, %seen_column_combinations);
831 for my $c_name ($rsrc->unique_constraint_names) {
832 next if $seen_column_combinations{
833 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
836 push @unique_queries, try {
837 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
841 $final_cond = @unique_queries
842 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
843 : $self->_non_unique_find_fallback ($call_cond, $attrs)
847 # Run the query, passing the result_class since it should propagate for find
848 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
849 if ($rs->_resolved_attrs->{collapse}) {
851 carp "Query returned more than one row" if $rs->next;
859 # This is a stop-gap method as agreed during the discussion on find() cleanup:
860 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
862 # It is invoked when find() is called in legacy-mode with insufficiently-unique
863 # condition. It is provided for overrides until a saner way forward is devised
865 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
866 # the road. Please adjust your tests accordingly to catch this situation early
867 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
869 # The method will not be removed without an adequately complete replacement
870 # for strict-mode enforcement
871 sub _non_unique_find_fallback {
872 my ($self, $cond, $attrs) = @_;
874 return $self->_qualify_cond_columns(
876 exists $attrs->{alias}
878 : $self->{attrs}{alias}
883 sub _qualify_cond_columns {
884 my ($self, $cond, $alias) = @_;
886 my %aliased = %$cond;
887 for (keys %aliased) {
888 $aliased{"$alias.$_"} = delete $aliased{$_}
895 sub _build_unique_cond {
896 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
898 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
900 # combination may fail if $self->{cond} is non-trivial
901 my ($final_cond) = try {
902 $self->_merge_with_rscond ($extra_cond)
907 # trim out everything not in $columns
908 $final_cond = { map {
909 exists $final_cond->{$_}
910 ? ( $_ => $final_cond->{$_} )
914 if (my @missing = grep
915 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
918 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
920 join (', ', map { "'$_'" } @missing),
927 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
929 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
931 carp_unique ( sprintf (
932 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
933 . 'values in column(s): %s). This is almost certainly not what you wanted, '
934 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
936 join (', ', map { "'$_'" } @undefs),
943 =head2 search_related
947 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
949 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
953 $new_rs = $cd_rs->search_related('artist', {
957 Searches the specified relationship, optionally specifying a condition and
958 attributes for matching records. See L</ATTRIBUTES> for more information.
960 In list context, C<< ->all() >> is called implicitly on the resultset, thus
961 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
963 See also L</search_related_rs>.
968 return shift->related_resultset(shift)->search(@_);
971 =head2 search_related_rs
973 This method works exactly the same as search_related, except that
974 it guarantees a resultset, even in list context.
978 sub search_related_rs {
979 return shift->related_resultset(shift)->search_rs(@_);
986 =item Arguments: none
988 =item Return Value: L<$cursor|DBIx::Class::Cursor>
992 Returns a storage-driven cursor to the given resultset. See
993 L<DBIx::Class::Cursor> for more information.
1000 return $self->{cursor} ||= do {
1001 my $attrs = { %{$self->_resolved_attrs } };
1002 $self->result_source->storage->select(
1003 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1012 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1014 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1018 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1020 Inflates the first result without creating a cursor if the resultset has
1021 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1024 While this method can take an optional search condition (just like L</search>)
1025 being a fast-code-path it does not recognize search attributes. If you need to
1026 add extra joins or similar, call L</search> and then chain-call L</single> on the
1027 L<DBIx::Class::ResultSet> returned.
1033 As of 0.08100, this method enforces the assumption that the preceding
1034 query returns only one row. If more than one row is returned, you will receive
1037 Query returned more than one row
1039 In this case, you should be using L</next> or L</find> instead, or if you really
1040 know what you are doing, use the L</rows> attribute to explicitly limit the size
1043 This method will also throw an exception if it is called on a resultset prefetching
1044 has_many, as such a prefetch implies fetching multiple rows from the database in
1045 order to assemble the resulting object.
1052 my ($self, $where) = @_;
1054 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1057 my $attrs = { %{$self->_resolved_attrs} };
1059 $self->throw_exception(
1060 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
1061 ) if $attrs->{collapse};
1064 if (defined $attrs->{where}) {
1067 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1068 $where, delete $attrs->{where} ]
1071 $attrs->{where} = $where;
1075 my $data = [ $self->result_source->storage->select_single(
1076 $attrs->{from}, $attrs->{select},
1077 $attrs->{where}, $attrs
1079 return undef unless @$data;
1080 $self->{_stashed_rows} = [ $data ];
1081 $self->_construct_results->[0];
1087 # Recursively collapse the query, accumulating values for each column.
1089 sub _collapse_query {
1090 my ($self, $query, $collapsed) = @_;
1094 if (ref $query eq 'ARRAY') {
1095 foreach my $subquery (@$query) {
1096 next unless ref $subquery; # -or
1097 $collapsed = $self->_collapse_query($subquery, $collapsed);
1100 elsif (ref $query eq 'HASH') {
1101 if (keys %$query and (keys %$query)[0] eq '-and') {
1102 foreach my $subquery (@{$query->{-and}}) {
1103 $collapsed = $self->_collapse_query($subquery, $collapsed);
1107 foreach my $col (keys %$query) {
1108 my $value = $query->{$col};
1109 $collapsed->{$col}{$value}++;
1121 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1123 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1127 my $max_length = $rs->get_column('length')->max;
1129 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1134 my ($self, $column) = @_;
1135 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1143 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1145 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1149 # WHERE title LIKE '%blue%'
1150 $cd_rs = $rs->search_like({ title => '%blue%'});
1152 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1153 that this is simply a convenience method retained for ex Class::DBI users.
1154 You most likely want to use L</search> with specific operators.
1156 For more information, see L<DBIx::Class::Manual::Cookbook>.
1158 This method is deprecated and will be removed in 0.09. Use L</search()>
1159 instead. An example conversion is:
1161 ->search_like({ foo => 'bar' });
1165 ->search({ foo => { like => 'bar' } });
1172 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1173 .' Instead use ->search({ x => { -like => "y%" } })'
1174 .' (note the outer pair of {}s - they are important!)'
1176 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1177 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1178 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1179 return $class->search($query, { %$attrs });
1186 =item Arguments: $first, $last
1188 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1192 Returns a resultset or object list representing a subset of elements from the
1193 resultset slice is called on. Indexes are from 0, i.e., to get the first
1194 three records, call:
1196 my ($one, $two, $three) = $rs->slice(0, 2);
1201 my ($self, $min, $max) = @_;
1202 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1203 $attrs->{offset} = $self->{attrs}{offset} || 0;
1204 $attrs->{offset} += $min;
1205 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1206 return $self->search(undef, $attrs);
1207 #my $slice = (ref $self)->new($self->result_source, $attrs);
1208 #return (wantarray ? $slice->all : $slice);
1215 =item Arguments: none
1217 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1221 Returns the next element in the resultset (C<undef> is there is none).
1223 Can be used to efficiently iterate over records in the resultset:
1225 my $rs = $schema->resultset('CD')->search;
1226 while (my $cd = $rs->next) {
1230 Note that you need to store the resultset object, and call C<next> on it.
1231 Calling C<< resultset('Table')->next >> repeatedly will always return the
1232 first record from the resultset.
1239 if (my $cache = $self->get_cache) {
1240 $self->{all_cache_position} ||= 0;
1241 return $cache->[$self->{all_cache_position}++];
1244 if ($self->{attrs}{cache}) {
1245 delete $self->{pager};
1246 $self->{all_cache_position} = 1;
1247 return ($self->all)[0];
1250 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1252 $self->{_stashed_results} = $self->_construct_results
1255 return shift @{$self->{_stashed_results}};
1258 # Constructs as many results as it can in one pass while respecting
1259 # cursor laziness. Several modes of operation:
1261 # * Always builds everything present in @{$self->{_stashed_rows}}
1262 # * If called with $fetch_all true - pulls everything off the cursor and
1263 # builds all result structures (or objects) in one pass
1264 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1265 # and if the resultset is ordered properly by the left side:
1266 # * Fetches stuff off the cursor until the "master object" changes,
1267 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1269 # * Just fetches, and collapses/constructs everything as if $fetch_all
1270 # was requested (there is no other way to collapse except for an
1272 # * If no collapse is requested - just get the next row, construct and
1274 sub _construct_results {
1275 my ($self, $fetch_all) = @_;
1277 my $rsrc = $self->result_source;
1278 my $attrs = $self->_resolved_attrs;
1280 if (!$fetch_all and ! $attrs->{order_by} and $attrs->{collapse}) {
1281 # default order for collapsing unless the user asked for something
1282 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} $rsrc->primary_columns ];
1283 $attrs->{_ordered_for_collapse} = 1;
1284 $attrs->{_order_is_artificial} = 1;
1287 my $cursor = $self->cursor;
1289 # this will be used as both initial raw-row collector AND as a RV of
1290 # _construct_results. Not regrowing the array twice matters a lot...
1291 # a surprising amount actually
1292 my $rows = delete $self->{_stashed_rows};
1295 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1296 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1298 elsif( $attrs->{collapse} ) {
1300 $attrs->{_ordered_for_collapse} = (!$attrs->{order_by}) ? 0 : do {
1301 my $st = $rsrc->schema->storage;
1304 ( $st->_extract_order_criteria($attrs->{order_by}) )
1307 my $colinfos = $st->_resolve_column_info($attrs->{from}, \@ord_cols);
1309 for (0 .. $#ord_cols) {
1311 ! $colinfos->{$ord_cols[$_]}
1313 $colinfos->{$ord_cols[$_]}{-result_source} != $rsrc
1315 splice @ord_cols, $_;
1320 # since all we check here are the start of the order_by belonging to the
1321 # top level $rsrc, a present identifying set will mean that the resultset
1322 # is ordered by its leftmost table in a tsable manner
1323 (@ord_cols and $rsrc->_identifying_column_set({ map
1324 { $colinfos->{$_}{-colname} => $colinfos->{$_} }
1327 } unless defined $attrs->{_ordered_for_collapse};
1329 if (! $attrs->{_ordered_for_collapse}) {
1332 # instead of looping over ->next, use ->all in stealth mode
1333 # *without* calling a ->reset afterwards
1334 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1335 if (! $cursor->{_done}) {
1336 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1337 $cursor->{_done} = 1;
1342 if (! $fetch_all and ! @{$rows||[]} ) {
1343 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1344 if (scalar (my @r = $cursor->next) ) {
1349 return undef unless @{$rows||[]};
1351 my @extra_collapser_args;
1352 if ($attrs->{collapse} and ! $fetch_all ) {
1354 @extra_collapser_args = (
1355 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1356 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1357 ($self->{_stashed_rows} = []), # where does it stuff excess
1361 # hotspot - skip the setter
1362 my $res_class = $self->_result_class;
1364 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1365 $res_class->can ('inflate_result')
1366 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1369 my $infmap = $attrs->{as};
1372 $self->{_result_inflator}{is_core_row} = ( (
1375 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1376 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1378 $self->{_result_inflator}{is_hri} = ( (
1379 ! $self->{_result_inflator}{is_core_row}
1382 require DBIx::Class::ResultClass::HashRefInflator
1384 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1386 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1389 if (! $attrs->{_related_results_construction}) {
1390 # construct a much simpler array->hash folder for the one-table cases right here
1391 if ($self->{_result_inflator}{is_hri}) {
1392 for my $r (@$rows) {
1393 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1396 # FIXME SUBOPTIMAL this is a very very very hot spot
1397 # while rather optimal we can *still* do much better, by
1398 # building a smarter Row::inflate_result(), and
1399 # switch to feeding it data via a much leaner interface
1401 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1402 # this particular resultset size
1403 elsif (@$rows < 60) {
1404 for my $r (@$rows) {
1405 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1410 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1411 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1415 # Special-case multi-object HRI (we always prune, and there is no $inflator_cref pass)
1416 elsif ($self->{_result_inflator}{is_hri}) {
1417 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1419 inflate_map => $infmap,
1420 selection => $attrs->{select},
1421 collapse => $attrs->{collapse},
1422 premultiplied => $attrs->{_main_source_premultiplied},
1424 prune_null_branches => 1,
1425 }) )->($rows, @extra_collapser_args);
1427 # Regular multi-object
1429 my $parser_type = $self->{_result_inflator}{is_core_row} ? 'classic_pruning' : 'classic_nonpruning';
1431 ( $self->{_row_parser}{$parser_type} ||= $rsrc->_mk_row_parser({
1433 inflate_map => $infmap,
1434 selection => $attrs->{select},
1435 collapse => $attrs->{collapse},
1436 premultiplied => $attrs->{_main_source_premultiplied},
1437 prune_null_branches => $self->{_result_inflator}{is_core_row},
1438 }) )->($rows, @extra_collapser_args);
1440 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1444 if ($attrs->{record_filter}) {
1445 $_ = $attrs->{record_filter}->($_) for @$rows;
1451 =head2 result_source
1455 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1457 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1461 An accessor for the primary ResultSource object from which this ResultSet
1468 =item Arguments: $result_class?
1470 =item Return Value: $result_class
1474 An accessor for the class to use when creating result objects. Defaults to
1475 C<< result_source->result_class >> - which in most cases is the name of the
1476 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1478 Note that changing the result_class will also remove any components
1479 that were originally loaded in the source class via
1480 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1481 in the original source class will not run.
1486 my ($self, $result_class) = @_;
1487 if ($result_class) {
1489 # don't fire this for an object
1490 $self->ensure_class_loaded($result_class)
1491 unless ref($result_class);
1493 if ($self->get_cache) {
1494 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1496 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1497 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1498 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1501 $self->_result_class($result_class);
1503 delete $self->{_result_inflator};
1505 $self->_result_class;
1512 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1514 =item Return Value: $count
1518 Performs an SQL C<COUNT> with the same query as the resultset was built
1519 with to find the number of elements. Passing arguments is equivalent to
1520 C<< $rs->search ($cond, \%attrs)->count >>
1526 return $self->search(@_)->count if @_ and defined $_[0];
1527 return scalar @{ $self->get_cache } if $self->get_cache;
1529 my $attrs = { %{ $self->_resolved_attrs } };
1531 # this is a little optimization - it is faster to do the limit
1532 # adjustments in software, instead of a subquery
1533 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1536 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1537 $crs = $self->_count_subq_rs ($attrs);
1540 $crs = $self->_count_rs ($attrs);
1542 my $count = $crs->next;
1544 $count -= $offset if $offset;
1545 $count = $rows if $rows and $rows < $count;
1546 $count = 0 if ($count < 0);
1555 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1557 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1561 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1562 This can be very handy for subqueries:
1564 ->search( { amount => $some_rs->count_rs->as_query } )
1566 As with regular resultsets the SQL query will be executed only after
1567 the resultset is accessed via L</next> or L</all>. That would return
1568 the same single value obtainable via L</count>.
1574 return $self->search(@_)->count_rs if @_;
1576 # this may look like a lack of abstraction (count() does about the same)
1577 # but in fact an _rs *must* use a subquery for the limits, as the
1578 # software based limiting can not be ported if this $rs is to be used
1579 # in a subquery itself (i.e. ->as_query)
1580 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1581 return $self->_count_subq_rs;
1584 return $self->_count_rs;
1589 # returns a ResultSetColumn object tied to the count query
1592 my ($self, $attrs) = @_;
1594 my $rsrc = $self->result_source;
1595 $attrs ||= $self->_resolved_attrs;
1597 my $tmp_attrs = { %$attrs };
1598 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1599 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1601 # overwrite the selector (supplied by the storage)
1602 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1603 $tmp_attrs->{as} = 'count';
1605 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1611 # same as above but uses a subquery
1613 sub _count_subq_rs {
1614 my ($self, $attrs) = @_;
1616 my $rsrc = $self->result_source;
1617 $attrs ||= $self->_resolved_attrs;
1619 my $sub_attrs = { %$attrs };
1620 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1621 delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/};
1623 # if we multi-prefetch we group_by something unique, as this is what we would
1624 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1625 if ( $attrs->{collapse} ) {
1626 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1627 $rsrc->_identifying_column_set || $self->throw_exception(
1628 'Unable to construct a unique group_by criteria properly collapsing the '
1629 . 'has_many prefetch before count()'
1634 # Calculate subquery selector
1635 if (my $g = $sub_attrs->{group_by}) {
1637 my $sql_maker = $rsrc->storage->sql_maker;
1639 # necessary as the group_by may refer to aliased functions
1641 for my $sel (@{$attrs->{select}}) {
1642 $sel_index->{$sel->{-as}} = $sel
1643 if (ref $sel eq 'HASH' and $sel->{-as});
1646 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1647 # also look for named aggregates referred in the having clause
1648 # having often contains scalarrefs - thus parse it out entirely
1650 if ($attrs->{having}) {
1651 local $sql_maker->{having_bind};
1652 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1653 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1654 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1655 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1656 # if we don't unset it we screw up retarded but unfortunately working
1657 # 'MAX(foo.bar)' => { '>', 3 }
1658 $sql_maker->{name_sep} = '';
1661 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1663 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1666 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1667 # and if all fails for an utterly naive quoted scalar-with-function
1668 while ($having_sql =~ /
1669 $rquote $sep $lquote (.+?) $rquote
1671 [\s,] \w+ \. (\w+) [\s,]
1673 [\s,] $lquote (.+?) $rquote [\s,]
1675 my $part = $1 || $2 || $3; # one of them matched if we got here
1676 unless ($seen_having{$part}++) {
1683 my $colpiece = $sel_index->{$_} || $_;
1685 # unqualify join-based group_by's. Arcane but possible query
1686 # also horrible horrible hack to alias a column (not a func.)
1687 # (probably need to introduce SQLA syntax)
1688 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1691 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1693 push @{$sub_attrs->{select}}, $colpiece;
1697 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1698 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1701 return $rsrc->resultset_class
1702 ->new ($rsrc, $sub_attrs)
1704 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1705 ->get_column ('count');
1709 =head2 count_literal
1711 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1712 should only be used in that context. See L</search_literal> for further info.
1716 =item Arguments: $sql_fragment, @standalone_bind_values
1718 =item Return Value: $count
1722 Counts the results in a literal query. Equivalent to calling L</search_literal>
1723 with the passed arguments, then L</count>.
1727 sub count_literal { shift->search_literal(@_)->count; }
1733 =item Arguments: none
1735 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1739 Returns all elements in the resultset.
1746 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1749 delete @{$self}{qw/_stashed_rows _stashed_results/};
1751 if (my $c = $self->get_cache) {
1755 $self->cursor->reset;
1757 my $objs = $self->_construct_results('fetch_all') || [];
1759 $self->set_cache($objs) if $self->{attrs}{cache};
1768 =item Arguments: none
1770 =item Return Value: $self
1774 Resets the resultset's cursor, so you can iterate through the elements again.
1775 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1783 delete @{$self}{qw/_stashed_rows _stashed_results/};
1784 $self->{all_cache_position} = 0;
1785 $self->cursor->reset;
1793 =item Arguments: none
1795 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1799 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1800 an object for the first result (or C<undef> if the resultset is empty).
1805 return $_[0]->reset->next;
1811 # Determines whether and what type of subquery is required for the $rs operation.
1812 # If grouping is necessary either supplies its own, or verifies the current one
1813 # After all is done delegates to the proper storage method.
1815 sub _rs_update_delete {
1816 my ($self, $op, $values) = @_;
1818 my $rsrc = $self->result_source;
1819 my $storage = $rsrc->schema->storage;
1821 my $attrs = { %{$self->_resolved_attrs} };
1823 my $join_classifications;
1824 my $existing_group_by = delete $attrs->{group_by};
1826 # do we need a subquery for any reason?
1828 defined $existing_group_by
1830 # if {from} is unparseable wrap a subq
1831 ref($attrs->{from}) ne 'ARRAY'
1833 # limits call for a subq
1834 $self->_has_resolved_attr(qw/rows offset/)
1837 # simplify the joinmap, so we can further decide if a subq is necessary
1838 if (!$needs_subq and @{$attrs->{from}} > 1) {
1839 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1841 # check if there are any joins left after the prune
1842 if ( @{$attrs->{from}} > 1 ) {
1843 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1844 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1850 # any non-pruneable joins imply subq
1851 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1855 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1857 (ref $attrs->{from}[0]) ne 'HASH'
1859 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1863 # do we need anything like a subquery?
1864 if (! $needs_subq) {
1865 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1866 # a condition containing 'me' or other table prefixes will not work
1867 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1869 my $sqla = $rsrc->storage->sql_maker;
1870 local $sqla->{_dequalify_idents} = 1;
1871 \[ $sqla->_recurse_where($self->{cond}) ];
1875 # we got this far - means it is time to wrap a subquery
1876 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1878 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1884 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1885 delete $attrs->{$_} for qw/collapse select _prefetch_selector_range as/;
1886 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1887 $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins
1888 my $subrs = (ref $self)->new($rsrc, $attrs);
1890 if (@$idcols == 1) {
1891 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1893 elsif ($storage->_use_multicolumn_in) {
1894 # no syntax for calling this properly yet
1895 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1896 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1897 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1902 # if all else fails - get all primary keys and operate over a ORed set
1903 # wrap in a transaction for consistency
1904 # this is where the group_by/multiplication starts to matter
1908 keys %{ $join_classifications->{multiplying} || {} }
1910 # make sure if there is a supplied group_by it matches the columns compiled above
1911 # perfectly. Anything else can not be sanely executed on most databases so croak
1912 # right then and there
1913 if ($existing_group_by) {
1914 my @current_group_by = map
1915 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1920 join ("\x00", sort @current_group_by)
1922 join ("\x00", sort @{$attrs->{columns}} )
1924 $self->throw_exception (
1925 "You have just attempted a $op operation on a resultset which does group_by"
1926 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1927 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1928 . ' kind of queries. Please retry the operation with a modified group_by or'
1929 . ' without using one at all.'
1934 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1937 $guard = $storage->txn_scope_guard;
1940 for my $row ($subrs->cursor->all) {
1942 { $idcols->[$_] => $row->[$_] }
1949 my $res = $storage->$op (
1951 $op eq 'update' ? $values : (),
1955 $guard->commit if $guard;
1964 =item Arguments: \%values
1966 =item Return Value: $underlying_storage_rv
1970 Sets the specified columns in the resultset to the supplied values in a
1971 single query. Note that this will not run any accessor/set_column/update
1972 triggers, nor will it update any result object instances derived from this
1973 resultset (this includes the contents of the L<resultset cache|/set_cache>
1974 if any). See L</update_all> if you need to execute any on-update
1975 triggers or cascades defined either by you or a
1976 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1978 The return value is a pass through of what the underlying
1979 storage backend returned, and may vary. See L<DBI/execute> for the most
1984 Note that L</update> does not process/deflate any of the values passed in.
1985 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1986 ensure manually that any value passed to this method will stringify to
1987 something the RDBMS knows how to deal with. A notable example is the
1988 handling of L<DateTime> objects, for more info see:
1989 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1994 my ($self, $values) = @_;
1995 $self->throw_exception('Values for update must be a hash')
1996 unless ref $values eq 'HASH';
1998 return $self->_rs_update_delete ('update', $values);
2005 =item Arguments: \%values
2007 =item Return Value: 1
2011 Fetches all objects and updates them one at a time via
2012 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2013 triggers, while L</update> will not.
2018 my ($self, $values) = @_;
2019 $self->throw_exception('Values for update_all must be a hash')
2020 unless ref $values eq 'HASH';
2022 my $guard = $self->result_source->schema->txn_scope_guard;
2023 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2032 =item Arguments: none
2034 =item Return Value: $underlying_storage_rv
2038 Deletes the rows matching this resultset in a single query. Note that this
2039 will not run any delete triggers, nor will it alter the
2040 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2041 derived from this resultset (this includes the contents of the
2042 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2043 execute any on-delete triggers or cascades defined either by you or a
2044 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2046 The return value is a pass through of what the underlying storage backend
2047 returned, and may vary. See L<DBI/execute> for the most common case.
2053 $self->throw_exception('delete does not accept any arguments')
2056 return $self->_rs_update_delete ('delete');
2063 =item Arguments: none
2065 =item Return Value: 1
2069 Fetches all objects and deletes them one at a time via
2070 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2071 triggers, while L</delete> will not.
2077 $self->throw_exception('delete_all does not accept any arguments')
2080 my $guard = $self->result_source->schema->txn_scope_guard;
2081 $_->delete for $self->all;
2090 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2092 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2096 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2103 The context of this method call has an important effect on what is
2104 submitted to storage. In void context data is fed directly to fastpath
2105 insertion routines provided by the underlying storage (most often
2106 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2107 L<insert|DBIx::Class::Row/insert> calls on the
2108 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2109 augmentation of these methods provided by components. For example if you
2110 are using something like L<DBIx::Class::UUIDColumns> to create primary
2111 keys for you, you will find that your PKs are empty. In this case you
2112 will have to explicitly force scalar or list context in order to create
2117 In non-void (scalar or list) context, this method is simply a wrapper
2118 for L</create>. Depending on list or scalar context either a list of
2119 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2120 containing these objects is returned.
2122 When supplying data in "arrayref of arrayrefs" invocation style, the
2123 first element should be a list of column names and each subsequent
2124 element should be a data value in the earlier specified column order.
2127 $Arstist_rs->populate([
2128 [ qw( artistid name ) ],
2129 [ 100, 'A Formally Unknown Singer' ],
2130 [ 101, 'A singer that jumped the shark two albums ago' ],
2131 [ 102, 'An actually cool singer' ],
2134 For the arrayref of hashrefs style each hashref should be a structure
2135 suitable for passing to L</create>. Multi-create is also permitted with
2138 $schema->resultset("Artist")->populate([
2139 { artistid => 4, name => 'Manufactured Crap', cds => [
2140 { title => 'My First CD', year => 2006 },
2141 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2144 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2145 { title => 'My parents sold me to a record company', year => 2005 },
2146 { title => 'Why Am I So Ugly?', year => 2006 },
2147 { title => 'I Got Surgery and am now Popular', year => 2007 }
2152 If you attempt a void-context multi-create as in the example above (each
2153 Artist also has the related list of CDs), and B<do not> supply the
2154 necessary autoinc foreign key information, this method will proxy to the
2155 less efficient L</create>, and then throw the Result objects away. In this
2156 case there are obviously no benefits to using this method over L</create>.
2163 # cruft placed in standalone method
2164 my $data = $self->_normalize_populate_args(@_);
2166 return unless @$data;
2168 if(defined wantarray) {
2169 my @created = map { $self->create($_) } @$data;
2170 return wantarray ? @created : \@created;
2173 my $first = $data->[0];
2175 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2176 # it relationship data
2177 my (@rels, @columns);
2178 my $rsrc = $self->result_source;
2179 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2180 for (keys %$first) {
2181 my $ref = ref $first->{$_};
2182 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2188 my @pks = $rsrc->primary_columns;
2190 ## do the belongs_to relationships
2191 foreach my $index (0..$#$data) {
2193 # delegate to create() for any dataset without primary keys with specified relationships
2194 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2196 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2197 my @ret = $self->populate($data);
2203 foreach my $rel (@rels) {
2204 next unless ref $data->[$index]->{$rel} eq "HASH";
2205 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2206 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2207 my $related = $result->result_source->_resolve_condition(
2208 $reverse_relinfo->{cond},
2214 delete $data->[$index]->{$rel};
2215 $data->[$index] = {%{$data->[$index]}, %$related};
2217 push @columns, keys %$related if $index == 0;
2221 ## inherit the data locked in the conditions of the resultset
2222 my ($rs_data) = $self->_merge_with_rscond({});
2223 delete @{$rs_data}{@columns};
2225 ## do bulk insert on current row
2226 $rsrc->storage->insert_bulk(
2228 [@columns, keys %$rs_data],
2229 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2232 ## do the has_many relationships
2233 foreach my $item (@$data) {
2237 foreach my $rel (@rels) {
2238 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2240 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2242 my $child = $main_row->$rel;
2244 my $related = $child->result_source->_resolve_condition(
2245 $rels->{$rel}{cond},
2251 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2252 my @populate = map { {%$_, %$related} } @rows_to_add;
2254 $child->populate( \@populate );
2261 # populate() argumnets went over several incarnations
2262 # What we ultimately support is AoH
2263 sub _normalize_populate_args {
2264 my ($self, $arg) = @_;
2266 if (ref $arg eq 'ARRAY') {
2270 elsif (ref $arg->[0] eq 'HASH') {
2273 elsif (ref $arg->[0] eq 'ARRAY') {
2275 my @colnames = @{$arg->[0]};
2276 foreach my $values (@{$arg}[1 .. $#$arg]) {
2277 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2283 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2290 =item Arguments: none
2292 =item Return Value: L<$pager|Data::Page>
2296 Returns a L<Data::Page> object for the current resultset. Only makes
2297 sense for queries with a C<page> attribute.
2299 To get the full count of entries for a paged resultset, call
2300 C<total_entries> on the L<Data::Page> object.
2307 return $self->{pager} if $self->{pager};
2309 my $attrs = $self->{attrs};
2310 if (!defined $attrs->{page}) {
2311 $self->throw_exception("Can't create pager for non-paged rs");
2313 elsif ($attrs->{page} <= 0) {
2314 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2316 $attrs->{rows} ||= 10;
2318 # throw away the paging flags and re-run the count (possibly
2319 # with a subselect) to get the real total count
2320 my $count_attrs = { %$attrs };
2321 delete @{$count_attrs}{qw/rows offset page pager/};
2323 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2325 require DBIx::Class::ResultSet::Pager;
2326 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2327 sub { $total_rs->count }, #lazy-get the total
2329 $self->{attrs}{page},
2337 =item Arguments: $page_number
2339 =item Return Value: L<$resultset|/search>
2343 Returns a resultset for the $page_number page of the resultset on which page
2344 is called, where each page contains a number of rows equal to the 'rows'
2345 attribute set on the resultset (10 by default).
2350 my ($self, $page) = @_;
2351 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2358 =item Arguments: \%col_data
2360 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2364 Creates a new result object in the resultset's result class and returns
2365 it. The row is not inserted into the database at this point, call
2366 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2367 will tell you whether the result object has been inserted or not.
2369 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2374 my ($self, $values) = @_;
2376 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2379 $self->throw_exception( "new_result expects a hashref" )
2380 unless (ref $values eq 'HASH');
2382 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2384 my $new = $self->result_class->new({
2386 ( @$cols_from_relations
2387 ? (-cols_from_relations => $cols_from_relations)
2390 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2394 reftype($new) eq 'HASH'
2400 carp_unique (sprintf (
2401 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2402 $self->result_class,
2409 # _merge_with_rscond
2411 # Takes a simple hash of K/V data and returns its copy merged with the
2412 # condition already present on the resultset. Additionally returns an
2413 # arrayref of value/condition names, which were inferred from related
2414 # objects (this is needed for in-memory related objects)
2415 sub _merge_with_rscond {
2416 my ($self, $data) = @_;
2418 my (%new_data, @cols_from_relations);
2420 my $alias = $self->{attrs}{alias};
2422 if (! defined $self->{cond}) {
2423 # just massage $data below
2425 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2426 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2427 @cols_from_relations = keys %new_data;
2429 elsif (ref $self->{cond} ne 'HASH') {
2430 $self->throw_exception(
2431 "Can't abstract implicit construct, resultset condition not a hash"
2435 # precendence must be given to passed values over values inherited from
2436 # the cond, so the order here is important.
2437 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2438 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2440 while ( my($col, $value) = each %implied ) {
2441 my $vref = ref $value;
2447 (keys %$value)[0] eq '='
2449 $new_data{$col} = $value->{'='};
2451 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2452 $new_data{$col} = $value;
2459 %{ $self->_remove_alias($data, $alias) },
2462 return (\%new_data, \@cols_from_relations);
2465 # _has_resolved_attr
2467 # determines if the resultset defines at least one
2468 # of the attributes supplied
2470 # used to determine if a subquery is neccessary
2472 # supports some virtual attributes:
2474 # This will scan for any joins being present on the resultset.
2475 # It is not a mere key-search but a deep inspection of {from}
2478 sub _has_resolved_attr {
2479 my ($self, @attr_names) = @_;
2481 my $attrs = $self->_resolved_attrs;
2485 for my $n (@attr_names) {
2486 if (grep { $n eq $_ } (qw/-join/) ) {
2487 $extra_checks{$n}++;
2491 my $attr = $attrs->{$n};
2493 next if not defined $attr;
2495 if (ref $attr eq 'HASH') {
2496 return 1 if keys %$attr;
2498 elsif (ref $attr eq 'ARRAY') {
2506 # a resolved join is expressed as a multi-level from
2508 $extra_checks{-join}
2510 ref $attrs->{from} eq 'ARRAY'
2512 @{$attrs->{from}} > 1
2520 # Recursively collapse the condition.
2522 sub _collapse_cond {
2523 my ($self, $cond, $collapsed) = @_;
2527 if (ref $cond eq 'ARRAY') {
2528 foreach my $subcond (@$cond) {
2529 next unless ref $subcond; # -or
2530 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2533 elsif (ref $cond eq 'HASH') {
2534 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2535 foreach my $subcond (@{$cond->{-and}}) {
2536 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2540 foreach my $col (keys %$cond) {
2541 my $value = $cond->{$col};
2542 $collapsed->{$col} = $value;
2552 # Remove the specified alias from the specified query hash. A copy is made so
2553 # the original query is not modified.
2556 my ($self, $query, $alias) = @_;
2558 my %orig = %{ $query || {} };
2561 foreach my $key (keys %orig) {
2563 $unaliased{$key} = $orig{$key};
2566 $unaliased{$1} = $orig{$key}
2567 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2577 =item Arguments: none
2579 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2583 Returns the SQL query and bind vars associated with the invocant.
2585 This is generally used as the RHS for a subquery.
2592 my $attrs = { %{ $self->_resolved_attrs } };
2597 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2598 # $sql also has no wrapping parenthesis in list ctx
2600 my $sqlbind = $self->result_source->storage
2601 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2610 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2612 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2616 my $artist = $schema->resultset('Artist')->find_or_new(
2617 { artist => 'fred' }, { key => 'artists' });
2619 $cd->cd_to_producer->find_or_new({ producer => $producer },
2620 { key => 'primary });
2622 Find an existing record from this resultset using L</find>. if none exists,
2623 instantiate a new result object and return it. The object will not be saved
2624 into your storage until you call L<DBIx::Class::Row/insert> on it.
2626 You most likely want this method when looking for existing rows using a unique
2627 constraint that is not the primary key, or looking for related rows.
2629 If you want objects to be saved immediately, use L</find_or_create> instead.
2631 B<Note>: Make sure to read the documentation of L</find> and understand the
2632 significance of the C<key> attribute, as its lack may skew your search, and
2633 subsequently result in spurious new objects.
2635 B<Note>: Take care when using C<find_or_new> with a table having
2636 columns with default values that you intend to be automatically
2637 supplied by the database (e.g. an auto_increment primary key column).
2638 In normal usage, the value of such columns should NOT be included at
2639 all in the call to C<find_or_new>, even when set to C<undef>.
2645 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2646 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2647 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2650 return $self->new_result($hash);
2657 =item Arguments: \%col_data
2659 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2663 Attempt to create a single new row or a row with multiple related rows
2664 in the table represented by the resultset (and related tables). This
2665 will not check for duplicate rows before inserting, use
2666 L</find_or_create> to do that.
2668 To create one row for this resultset, pass a hashref of key/value
2669 pairs representing the columns of the table and the values you wish to
2670 store. If the appropriate relationships are set up, foreign key fields
2671 can also be passed an object representing the foreign row, and the
2672 value will be set to its primary key.
2674 To create related objects, pass a hashref of related-object column values
2675 B<keyed on the relationship name>. If the relationship is of type C<multi>
2676 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2677 The process will correctly identify columns holding foreign keys, and will
2678 transparently populate them from the keys of the corresponding relation.
2679 This can be applied recursively, and will work correctly for a structure
2680 with an arbitrary depth and width, as long as the relationships actually
2681 exists and the correct column data has been supplied.
2683 Instead of hashrefs of plain related data (key/value pairs), you may
2684 also pass new or inserted objects. New objects (not inserted yet, see
2685 L</new_result>), will be inserted into their appropriate tables.
2687 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2689 Example of creating a new row.
2691 $person_rs->create({
2692 name=>"Some Person",
2693 email=>"somebody@someplace.com"
2696 Example of creating a new row and also creating rows in a related C<has_many>
2697 or C<has_one> resultset. Note Arrayref.
2700 { artistid => 4, name => 'Manufactured Crap', cds => [
2701 { title => 'My First CD', year => 2006 },
2702 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2707 Example of creating a new row and also creating a row in a related
2708 C<belongs_to> resultset. Note Hashref.
2711 title=>"Music for Silly Walks",
2714 name=>"Silly Musician",
2722 When subclassing ResultSet never attempt to override this method. Since
2723 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2724 lot of the internals simply never call it, so your override will be
2725 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2726 or L<DBIx::Class::Row/insert> depending on how early in the
2727 L</create> process you need to intervene. See also warning pertaining to
2735 my ($self, $attrs) = @_;
2736 $self->throw_exception( "create needs a hashref" )
2737 unless ref $attrs eq 'HASH';
2738 return $self->new_result($attrs)->insert;
2741 =head2 find_or_create
2745 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2747 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2751 $cd->cd_to_producer->find_or_create({ producer => $producer },
2752 { key => 'primary' });
2754 Tries to find a record based on its primary key or unique constraints; if none
2755 is found, creates one and returns that instead.
2757 my $cd = $schema->resultset('CD')->find_or_create({
2759 artist => 'Massive Attack',
2760 title => 'Mezzanine',
2764 Also takes an optional C<key> attribute, to search by a specific key or unique
2765 constraint. For example:
2767 my $cd = $schema->resultset('CD')->find_or_create(
2769 artist => 'Massive Attack',
2770 title => 'Mezzanine',
2772 { key => 'cd_artist_title' }
2775 B<Note>: Make sure to read the documentation of L</find> and understand the
2776 significance of the C<key> attribute, as its lack may skew your search, and
2777 subsequently result in spurious row creation.
2779 B<Note>: Because find_or_create() reads from the database and then
2780 possibly inserts based on the result, this method is subject to a race
2781 condition. Another process could create a record in the table after
2782 the find has completed and before the create has started. To avoid
2783 this problem, use find_or_create() inside a transaction.
2785 B<Note>: Take care when using C<find_or_create> with a table having
2786 columns with default values that you intend to be automatically
2787 supplied by the database (e.g. an auto_increment primary key column).
2788 In normal usage, the value of such columns should NOT be included at
2789 all in the call to C<find_or_create>, even when set to C<undef>.
2791 See also L</find> and L</update_or_create>. For information on how to declare
2792 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2794 If you need to know if an existing row was found or a new one created use
2795 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2796 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2799 my $cd = $schema->resultset('CD')->find_or_new({
2801 artist => 'Massive Attack',
2802 title => 'Mezzanine',
2806 if( !$cd->in_storage ) {
2813 sub find_or_create {
2815 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2816 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2817 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2820 return $self->create($hash);
2823 =head2 update_or_create
2827 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2829 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2833 $resultset->update_or_create({ col => $val, ... });
2835 Like L</find_or_create>, but if a row is found it is immediately updated via
2836 C<< $found_row->update (\%col_data) >>.
2839 Takes an optional C<key> attribute to search on a specific unique constraint.
2842 # In your application
2843 my $cd = $schema->resultset('CD')->update_or_create(
2845 artist => 'Massive Attack',
2846 title => 'Mezzanine',
2849 { key => 'cd_artist_title' }
2852 $cd->cd_to_producer->update_or_create({
2853 producer => $producer,
2859 B<Note>: Make sure to read the documentation of L</find> and understand the
2860 significance of the C<key> attribute, as its lack may skew your search, and
2861 subsequently result in spurious row creation.
2863 B<Note>: Take care when using C<update_or_create> with a table having
2864 columns with default values that you intend to be automatically
2865 supplied by the database (e.g. an auto_increment primary key column).
2866 In normal usage, the value of such columns should NOT be included at
2867 all in the call to C<update_or_create>, even when set to C<undef>.
2869 See also L</find> and L</find_or_create>. For information on how to declare
2870 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2872 If you need to know if an existing row was updated or a new one created use
2873 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2874 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2879 sub update_or_create {
2881 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2882 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2884 my $row = $self->find($cond, $attrs);
2886 $row->update($cond);
2890 return $self->create($cond);
2893 =head2 update_or_new
2897 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2899 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2903 $resultset->update_or_new({ col => $val, ... });
2905 Like L</find_or_new> but if a row is found it is immediately updated via
2906 C<< $found_row->update (\%col_data) >>.
2910 # In your application
2911 my $cd = $schema->resultset('CD')->update_or_new(
2913 artist => 'Massive Attack',
2914 title => 'Mezzanine',
2917 { key => 'cd_artist_title' }
2920 if ($cd->in_storage) {
2921 # the cd was updated
2924 # the cd is not yet in the database, let's insert it
2928 B<Note>: Make sure to read the documentation of L</find> and understand the
2929 significance of the C<key> attribute, as its lack may skew your search, and
2930 subsequently result in spurious new objects.
2932 B<Note>: Take care when using C<update_or_new> with a table having
2933 columns with default values that you intend to be automatically
2934 supplied by the database (e.g. an auto_increment primary key column).
2935 In normal usage, the value of such columns should NOT be included at
2936 all in the call to C<update_or_new>, even when set to C<undef>.
2938 See also L</find>, L</find_or_create> and L</find_or_new>.
2944 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2945 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2947 my $row = $self->find( $cond, $attrs );
2948 if ( defined $row ) {
2949 $row->update($cond);
2953 return $self->new_result($cond);
2960 =item Arguments: none
2962 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2966 Gets the contents of the cache for the resultset, if the cache is set.
2968 The cache is populated either by using the L</prefetch> attribute to
2969 L</search> or by calling L</set_cache>.
2981 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2983 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2987 Sets the contents of the cache for the resultset. Expects an arrayref
2988 of objects of the same class as those produced by the resultset. Note that
2989 if the cache is set, the resultset will return the cached objects rather
2990 than re-querying the database even if the cache attr is not set.
2992 The contents of the cache can also be populated by using the
2993 L</prefetch> attribute to L</search>.
2998 my ( $self, $data ) = @_;
2999 $self->throw_exception("set_cache requires an arrayref")
3000 if defined($data) && (ref $data ne 'ARRAY');
3001 $self->{all_cache} = $data;
3008 =item Arguments: none
3010 =item Return Value: undef
3014 Clears the cache for the resultset.
3019 shift->set_cache(undef);
3026 =item Arguments: none
3028 =item Return Value: true, if the resultset has been paginated
3036 return !!$self->{attrs}{page};
3043 =item Arguments: none
3045 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3053 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3056 =head2 related_resultset
3060 =item Arguments: $rel_name
3062 =item Return Value: L<$resultset|/search>
3066 Returns a related resultset for the supplied relationship name.
3068 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3072 sub related_resultset {
3073 my ($self, $rel) = @_;
3075 return $self->{related_resultsets}{$rel} ||= do {
3076 my $rsrc = $self->result_source;
3077 my $rel_info = $rsrc->relationship_info($rel);
3079 $self->throw_exception(
3080 "search_related: result source '" . $rsrc->source_name .
3081 "' has no such relationship $rel")
3084 my $attrs = $self->_chain_relationship($rel);
3086 my $join_count = $attrs->{seen_join}{$rel};
3088 my $alias = $self->result_source->storage
3089 ->relname_to_table_alias($rel, $join_count);
3091 # since this is search_related, and we already slid the select window inwards
3092 # (the select/as attrs were deleted in the beginning), we need to flip all
3093 # left joins to inner, so we get the expected results
3094 # read the comment on top of the actual function to see what this does
3095 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3098 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3099 delete @{$attrs}{qw(result_class alias)};
3103 if (my $cache = $self->get_cache) {
3104 $related_cache = [ map
3105 { @{$_->related_resultset($rel)->get_cache||[]} }
3110 my $rel_source = $rsrc->related_source($rel);
3114 # The reason we do this now instead of passing the alias to the
3115 # search_rs below is that if you wrap/overload resultset on the
3116 # source you need to know what alias it's -going- to have for things
3117 # to work sanely (e.g. RestrictWithObject wants to be able to add
3118 # extra query restrictions, and these may need to be $alias.)
3120 my $rel_attrs = $rel_source->resultset_attributes;
3121 local $rel_attrs->{alias} = $alias;
3123 $rel_source->resultset
3127 where => $attrs->{where},
3130 $new->set_cache($related_cache) if $related_cache;
3135 =head2 current_source_alias
3139 =item Arguments: none
3141 =item Return Value: $source_alias
3145 Returns the current table alias for the result source this resultset is built
3146 on, that will be used in the SQL query. Usually it is C<me>.
3148 Currently the source alias that refers to the result set returned by a
3149 L</search>/L</find> family method depends on how you got to the resultset: it's
3150 C<me> by default, but eg. L</search_related> aliases it to the related result
3151 source name (and keeps C<me> referring to the original result set). The long
3152 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3153 (and make this method unnecessary).
3155 Thus it's currently necessary to use this method in predefined queries (see
3156 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3157 source alias of the current result set:
3159 # in a result set class
3161 my ($self, $user) = @_;
3163 my $me = $self->current_source_alias;
3165 return $self->search({
3166 "$me.modified" => $user->id,
3172 sub current_source_alias {
3173 return (shift->{attrs} || {})->{alias} || 'me';
3176 =head2 as_subselect_rs
3180 =item Arguments: none
3182 =item Return Value: L<$resultset|/search>
3186 Act as a barrier to SQL symbols. The resultset provided will be made into a
3187 "virtual view" by including it as a subquery within the from clause. From this
3188 point on, any joined tables are inaccessible to ->search on the resultset (as if
3189 it were simply where-filtered without joins). For example:
3191 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3193 # 'x' now pollutes the query namespace
3195 # So the following works as expected
3196 my $ok_rs = $rs->search({'x.other' => 1});
3198 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3199 # def) we look for one row with contradictory terms and join in another table
3200 # (aliased 'x_2') which we never use
3201 my $broken_rs = $rs->search({'x.name' => 'def'});
3203 my $rs2 = $rs->as_subselect_rs;
3205 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3206 my $not_joined_rs = $rs2->search({'x.other' => 1});
3208 # works as expected: finds a 'table' row related to two x rows (abc and def)
3209 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3211 Another example of when one might use this would be to select a subset of
3212 columns in a group by clause:
3214 my $rs = $schema->resultset('Bar')->search(undef, {
3215 group_by => [qw{ id foo_id baz_id }],
3216 })->as_subselect_rs->search(undef, {
3217 columns => [qw{ id foo_id }]
3220 In the above example normally columns would have to be equal to the group by,
3221 but because we isolated the group by into a subselect the above works.
3225 sub as_subselect_rs {
3228 my $attrs = $self->_resolved_attrs;
3230 my $fresh_rs = (ref $self)->new (
3231 $self->result_source
3234 # these pieces will be locked in the subquery
3235 delete $fresh_rs->{cond};
3236 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3238 return $fresh_rs->search( {}, {
3240 $attrs->{alias} => $self->as_query,
3241 -alias => $attrs->{alias},
3242 -rsrc => $self->result_source,
3244 alias => $attrs->{alias},
3248 # This code is called by search_related, and makes sure there
3249 # is clear separation between the joins before, during, and
3250 # after the relationship. This information is needed later
3251 # in order to properly resolve prefetch aliases (any alias
3252 # with a relation_chain_depth less than the depth of the
3253 # current prefetch is not considered)
3255 # The increments happen twice per join. An even number means a
3256 # relationship specified via a search_related, whereas an odd
3257 # number indicates a join/prefetch added via attributes
3259 # Also this code will wrap the current resultset (the one we
3260 # chain to) in a subselect IFF it contains limiting attributes
3261 sub _chain_relationship {
3262 my ($self, $rel) = @_;
3263 my $source = $self->result_source;
3264 my $attrs = { %{$self->{attrs}||{}} };
3266 # we need to take the prefetch the attrs into account before we
3267 # ->_resolve_join as otherwise they get lost - captainL
3268 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3270 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
3272 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3275 my @force_subq_attrs = qw/offset rows group_by having/;
3278 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3280 $self->_has_resolved_attr (@force_subq_attrs)
3282 # Nuke the prefetch (if any) before the new $rs attrs
3283 # are resolved (prefetch is useless - we are wrapping
3284 # a subquery anyway).
3285 my $rs_copy = $self->search;
3286 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3287 $rs_copy->{attrs}{join},
3288 delete $rs_copy->{attrs}{prefetch},
3293 -alias => $attrs->{alias},
3294 $attrs->{alias} => $rs_copy->as_query,
3296 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3297 $seen->{-relation_chain_depth} = 0;
3299 elsif ($attrs->{from}) { #shallow copy suffices
3300 $from = [ @{$attrs->{from}} ];
3305 -alias => $attrs->{alias},
3306 $attrs->{alias} => $source->from,
3310 my $jpath = ($seen->{-relation_chain_depth})
3311 ? $from->[-1][0]{-join_path}
3314 my @requested_joins = $source->_resolve_join(
3321 push @$from, @requested_joins;
3323 $seen->{-relation_chain_depth}++;
3325 # if $self already had a join/prefetch specified on it, the requested
3326 # $rel might very well be already included. What we do in this case
3327 # is effectively a no-op (except that we bump up the chain_depth on
3328 # the join in question so we could tell it *is* the search_related)
3331 # we consider the last one thus reverse
3332 for my $j (reverse @requested_joins) {
3333 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3334 if ($rel eq $last_j) {
3335 $j->[0]{-relation_chain_depth}++;
3341 unless ($already_joined) {
3342 push @$from, $source->_resolve_join(
3350 $seen->{-relation_chain_depth}++;
3352 return {%$attrs, from => $from, seen_join => $seen};
3355 sub _resolved_attrs {
3357 return $self->{_attrs} if $self->{_attrs};
3359 my $attrs = { %{ $self->{attrs} || {} } };
3360 my $source = $self->result_source;
3361 my $alias = $attrs->{alias};
3363 # default selection list
3364 $attrs->{columns} = [ $source->columns ]
3365 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3367 # merge selectors together
3368 for (qw/columns select as/) {
3369 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3370 if $attrs->{$_} or $attrs->{"+$_"};
3373 # disassemble columns
3375 if (my $cols = delete $attrs->{columns}) {
3376 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3377 if (ref $c eq 'HASH') {
3378 for my $as (sort keys %$c) {
3379 push @sel, $c->{$as};
3390 # when trying to weed off duplicates later do not go past this point -
3391 # everything added from here on is unbalanced "anyone's guess" stuff
3392 my $dedup_stop_idx = $#as;
3394 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3396 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3397 if $attrs->{select};
3399 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3400 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3402 # disqualify all $alias.col as-bits (inflate-map mandated)
3403 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3405 # de-duplicate the result (remove *identical* select/as pairs)
3406 # and also die on duplicate {as} pointing to different {select}s
3407 # not using a c-style for as the condition is prone to shrinkage
3410 while ($i <= $dedup_stop_idx) {
3411 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3416 elsif ($seen->{$as[$i]}++) {
3417 $self->throw_exception(
3418 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3426 $attrs->{select} = \@sel;
3427 $attrs->{as} = \@as;
3429 $attrs->{from} ||= [{
3431 -alias => $self->{attrs}{alias},
3432 $self->{attrs}{alias} => $source->from,
3435 if ( $attrs->{join} || $attrs->{prefetch} ) {
3437 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3438 if ref $attrs->{from} ne 'ARRAY';
3440 my $join = (delete $attrs->{join}) || {};
3442 if ( defined $attrs->{prefetch} ) {
3443 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3446 $attrs->{from} = # have to copy here to avoid corrupting the original
3448 @{ $attrs->{from} },
3449 $source->_resolve_join(
3452 { %{ $attrs->{seen_join} || {} } },
3453 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3454 ? $attrs->{from}[-1][0]{-join_path}
3461 if ( defined $attrs->{order_by} ) {
3462 $attrs->{order_by} = (
3463 ref( $attrs->{order_by} ) eq 'ARRAY'
3464 ? [ @{ $attrs->{order_by} } ]
3465 : [ $attrs->{order_by} || () ]
3469 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3470 $attrs->{group_by} = [ $attrs->{group_by} ];
3473 # generate the distinct induced group_by early, as prefetch will be carried via a
3474 # subquery (since a group_by is present)
3475 if (delete $attrs->{distinct}) {
3476 if ($attrs->{group_by}) {
3477 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3480 # distinct affects only the main selection part, not what prefetch may
3482 $attrs->{group_by} = $source->storage->_group_over_selection (
3490 # generate selections based on the prefetch helper
3492 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3493 if defined $attrs->{prefetch};
3497 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3498 if $attrs->{_dark_selector};
3500 $attrs->{collapse} = 1;
3502 # this is a separate structure (we don't look in {from} directly)
3503 # as the resolver needs to shift things off the lists to work
3504 # properly (identical-prefetches on different branches)
3506 if (ref $attrs->{from} eq 'ARRAY') {
3508 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3510 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3511 next unless $j->[0]{-alias};
3512 next unless $j->[0]{-join_path};
3513 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3515 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3518 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3519 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3523 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3525 # we need to somehow mark which columns came from prefetch
3527 my $sel_end = $#{$attrs->{select}};
3528 $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
3531 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3532 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3535 if ( defined List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3536 $attrs->{_related_results_construction} = 1;
3539 $attrs->{collapse} = 0;
3542 # run through the resulting joinstructure (starting from our current slot)
3543 # and unset collapse if proven unnesessary
3545 # also while we are at it find out if the current root source has
3546 # been premultiplied by previous related_source chaining
3548 # this allows to predict whether a root object with all other relation
3549 # data set to NULL is in fact unique
3550 if ($attrs->{collapse}) {
3552 if (ref $attrs->{from} eq 'ARRAY') {
3554 if (@{$attrs->{from}} <= 1) {
3555 # no joins - no collapse
3556 $attrs->{collapse} = 0;
3559 # find where our table-spec starts
3560 my @fromlist = @{$attrs->{from}};
3562 my $t = shift @fromlist;
3565 # me vs join from-spec distinction - a ref means non-root
3566 if (ref $t eq 'ARRAY') {
3568 $is_multi ||= ! $t->{-is_single};
3570 last if ($t->{-alias} && $t->{-alias} eq $alias);
3571 $attrs->{_main_source_premultiplied} ||= $is_multi;
3574 # no non-singles remaining, nor any premultiplication - nothing to collapse
3576 ! $attrs->{_main_source_premultiplied}
3578 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3580 $attrs->{collapse} = 0;
3586 # if we can not analyze the from - err on the side of safety
3587 $attrs->{_main_source_premultiplied} = 1;
3591 # if both page and offset are specified, produce a combined offset
3592 # even though it doesn't make much sense, this is what pre 081xx has
3594 if (my $page = delete $attrs->{page}) {
3596 ($attrs->{rows} * ($page - 1))
3598 ($attrs->{offset} || 0)
3602 return $self->{_attrs} = $attrs;
3606 my ($self, $attr) = @_;
3608 if (ref $attr eq 'HASH') {
3609 return $self->_rollout_hash($attr);
3610 } elsif (ref $attr eq 'ARRAY') {
3611 return $self->_rollout_array($attr);
3617 sub _rollout_array {
3618 my ($self, $attr) = @_;
3621 foreach my $element (@{$attr}) {
3622 if (ref $element eq 'HASH') {
3623 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3624 } elsif (ref $element eq 'ARRAY') {
3625 # XXX - should probably recurse here
3626 push( @rolled_array, @{$self->_rollout_array($element)} );
3628 push( @rolled_array, $element );
3631 return \@rolled_array;
3635 my ($self, $attr) = @_;
3638 foreach my $key (keys %{$attr}) {
3639 push( @rolled_array, { $key => $attr->{$key} } );
3641 return \@rolled_array;
3644 sub _calculate_score {
3645 my ($self, $a, $b) = @_;
3647 if (defined $a xor defined $b) {
3650 elsif (not defined $a) {
3654 if (ref $b eq 'HASH') {
3655 my ($b_key) = keys %{$b};
3656 if (ref $a eq 'HASH') {
3657 my ($a_key) = keys %{$a};
3658 if ($a_key eq $b_key) {
3659 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3664 return ($a eq $b_key) ? 1 : 0;
3667 if (ref $a eq 'HASH') {
3668 my ($a_key) = keys %{$a};
3669 return ($b eq $a_key) ? 1 : 0;
3671 return ($b eq $a) ? 1 : 0;
3676 sub _merge_joinpref_attr {
3677 my ($self, $orig, $import) = @_;
3679 return $import unless defined($orig);
3680 return $orig unless defined($import);
3682 $orig = $self->_rollout_attr($orig);
3683 $import = $self->_rollout_attr($import);
3686 foreach my $import_element ( @{$import} ) {
3687 # find best candidate from $orig to merge $b_element into
3688 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3689 foreach my $orig_element ( @{$orig} ) {
3690 my $score = $self->_calculate_score( $orig_element, $import_element );
3691 if ($score > $best_candidate->{score}) {
3692 $best_candidate->{position} = $position;
3693 $best_candidate->{score} = $score;
3697 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3698 $import_key = '' if not defined $import_key;
3700 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3701 push( @{$orig}, $import_element );
3703 my $orig_best = $orig->[$best_candidate->{position}];
3704 # merge orig_best and b_element together and replace original with merged
3705 if (ref $orig_best ne 'HASH') {
3706 $orig->[$best_candidate->{position}] = $import_element;
3707 } elsif (ref $import_element eq 'HASH') {
3708 my ($key) = keys %{$orig_best};
3709 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3712 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3715 return @$orig ? $orig : ();
3723 require Hash::Merge;
3724 my $hm = Hash::Merge->new;
3726 $hm->specify_behavior({
3729 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3731 if ($defl xor $defr) {
3732 return [ $defl ? $_[0] : $_[1] ];
3737 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3741 return [$_[0], $_[1]];
3745 return $_[1] if !defined $_[0];
3746 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3747 return [$_[0], @{$_[1]}]
3750 return [] if !defined $_[0] and !keys %{$_[1]};
3751 return [ $_[1] ] if !defined $_[0];
3752 return [ $_[0] ] if !keys %{$_[1]};
3753 return [$_[0], $_[1]]
3758 return $_[0] if !defined $_[1];
3759 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3760 return [@{$_[0]}, $_[1]]
3763 my @ret = @{$_[0]} or return $_[1];
3764 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3765 my %idx = map { $_ => 1 } @ret;
3766 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3770 return [ $_[1] ] if ! @{$_[0]};
3771 return $_[0] if !keys %{$_[1]};
3772 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3773 return [ @{$_[0]}, $_[1] ];
3778 return [] if !keys %{$_[0]} and !defined $_[1];
3779 return [ $_[0] ] if !defined $_[1];
3780 return [ $_[1] ] if !keys %{$_[0]};
3781 return [$_[0], $_[1]]
3784 return [] if !keys %{$_[0]} and !@{$_[1]};
3785 return [ $_[0] ] if !@{$_[1]};
3786 return $_[1] if !keys %{$_[0]};
3787 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3788 return [ $_[0], @{$_[1]} ];
3791 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3792 return [ $_[0] ] if !keys %{$_[1]};
3793 return [ $_[1] ] if !keys %{$_[0]};
3794 return [ $_[0] ] if $_[0] eq $_[1];
3795 return [ $_[0], $_[1] ];
3798 } => 'DBIC_RS_ATTR_MERGER');
3802 return $hm->merge ($_[1], $_[2]);
3806 sub STORABLE_freeze {
3807 my ($self, $cloning) = @_;
3808 my $to_serialize = { %$self };
3810 # A cursor in progress can't be serialized (and would make little sense anyway)
3811 # the parser can be regenerated (and can't be serialized)
3812 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3814 # nor is it sensical to store a not-yet-fired-count pager
3815 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3816 delete $to_serialize->{pager};
3819 Storable::nfreeze($to_serialize);
3822 # need this hook for symmetry
3824 my ($self, $cloning, $serialized) = @_;
3826 %$self = %{ Storable::thaw($serialized) };
3832 =head2 throw_exception
3834 See L<DBIx::Class::Schema/throw_exception> for details.
3838 sub throw_exception {
3841 if (ref $self and my $rsrc = $self->result_source) {
3842 $rsrc->throw_exception(@_)
3845 DBIx::Class::Exception->throw(@_);
3853 # XXX: FIXME: Attributes docs need clearing up
3857 Attributes are used to refine a ResultSet in various ways when
3858 searching for data. They can be passed to any method which takes an
3859 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3862 Default attributes can be set on the result class using
3863 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3864 the CAVEATS on that feature before using it!)
3866 These are in no particular order:
3872 =item Value: ( $order_by | \@order_by | \%order_by )
3876 Which column(s) to order the results by.
3878 [The full list of suitable values is documented in
3879 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3882 If a single column name, or an arrayref of names is supplied, the
3883 argument is passed through directly to SQL. The hashref syntax allows
3884 for connection-agnostic specification of ordering direction:
3886 For descending order:
3888 order_by => { -desc => [qw/col1 col2 col3/] }
3890 For explicit ascending order:
3892 order_by => { -asc => 'col' }
3894 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3895 supported, although you are strongly encouraged to use the hashref
3896 syntax as outlined above.
3902 =item Value: \@columns | \%columns | $column
3906 Shortcut to request a particular set of columns to be retrieved. Each
3907 column spec may be a string (a table column name), or a hash (in which
3908 case the key is the C<as> value, and the value is used as the C<select>
3909 expression). Adds C<me.> onto the start of any column without a C<.> in
3910 it and sets C<select> from that, then auto-populates C<as> from
3911 C<select> as normal. (You may also use the C<cols> attribute, as in
3912 earlier versions of DBIC.)
3914 Essentially C<columns> does the same as L</select> and L</as>.
3916 columns => [ 'foo', { bar => 'baz' } ]
3920 select => [qw/foo baz/],
3927 =item Value: \@columns
3931 Indicates additional columns to be selected from storage. Works the same
3932 as L</columns> but adds columns to the selection. (You may also use the
3933 C<include_columns> attribute, as in earlier versions of DBIC). For
3936 $schema->resultset('CD')->search(undef, {
3937 '+columns' => ['artist.name'],
3941 would return all CDs and include a 'name' column to the information
3942 passed to object inflation. Note that the 'artist' is the name of the
3943 column (or relationship) accessor, and 'name' is the name of the column
3944 accessor in the related table.
3946 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3947 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3948 unary plus operator before it.
3950 =head2 include_columns
3954 =item Value: \@columns
3958 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3964 =item Value: \@select_columns
3968 Indicates which columns should be selected from the storage. You can use
3969 column names, or in the case of RDBMS back ends, function or stored procedure
3972 $rs = $schema->resultset('Employee')->search(undef, {
3975 { count => 'employeeid' },
3976 { max => { length => 'name' }, -as => 'longest_name' }
3981 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3983 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3984 use L</select>, to instruct DBIx::Class how to store the result of the column.
3985 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3986 identifier aliasing. You can however alias a function, so you can use it in
3987 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3988 attribute> supplied as shown in the example above.
3990 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3991 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3992 unary plus operator before it.
3998 Indicates additional columns to be selected from storage. Works the same as
3999 L</select> but adds columns to the default selection, instead of specifying
4008 =item Value: \@inflation_names
4012 Indicates column names for object inflation. That is L</as> indicates the
4013 slot name in which the column value will be stored within the
4014 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4015 identifier by the C<get_column> method (or via the object accessor B<if one
4016 with the same name already exists>) as shown below. The L</as> attribute has
4017 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4019 $rs = $schema->resultset('Employee')->search(undef, {
4022 { count => 'employeeid' },
4023 { max => { length => 'name' }, -as => 'longest_name' }
4032 If the object against which the search is performed already has an accessor
4033 matching a column name specified in C<as>, the value can be retrieved using
4034 the accessor as normal:
4036 my $name = $employee->name();
4038 If on the other hand an accessor does not exist in the object, you need to
4039 use C<get_column> instead:
4041 my $employee_count = $employee->get_column('employee_count');
4043 You can create your own accessors if required - see
4044 L<DBIx::Class::Manual::Cookbook> for details.
4050 Indicates additional column names for those added via L</+select>. See L</as>.
4058 =item Value: ($rel_name | \@rel_names | \%rel_names)
4062 Contains a list of relationships that should be joined for this query. For
4065 # Get CDs by Nine Inch Nails
4066 my $rs = $schema->resultset('CD')->search(
4067 { 'artist.name' => 'Nine Inch Nails' },
4068 { join => 'artist' }
4071 Can also contain a hash reference to refer to the other relation's relations.
4074 package MyApp::Schema::Track;
4075 use base qw/DBIx::Class/;
4076 __PACKAGE__->table('track');
4077 __PACKAGE__->add_columns(qw/trackid cd position title/);
4078 __PACKAGE__->set_primary_key('trackid');
4079 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4082 # In your application
4083 my $rs = $schema->resultset('Artist')->search(
4084 { 'track.title' => 'Teardrop' },
4086 join => { cd => 'track' },
4087 order_by => 'artist.name',
4091 You need to use the relationship (not the table) name in conditions,
4092 because they are aliased as such. The current table is aliased as "me", so
4093 you need to use me.column_name in order to avoid ambiguity. For example:
4095 # Get CDs from 1984 with a 'Foo' track
4096 my $rs = $schema->resultset('CD')->search(
4099 'tracks.name' => 'Foo'
4101 { join => 'tracks' }
4104 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4105 similarly for a third time). For e.g.
4107 my $rs = $schema->resultset('Artist')->search({
4108 'cds.title' => 'Down to Earth',
4109 'cds_2.title' => 'Popular',
4111 join => [ qw/cds cds/ ],
4114 will return a set of all artists that have both a cd with title 'Down
4115 to Earth' and a cd with title 'Popular'.
4117 If you want to fetch related objects from other tables as well, see L</prefetch>
4120 NOTE: An internal join-chain pruner will discard certain joins while
4121 constructing the actual SQL query, as long as the joins in question do not
4122 affect the retrieved result. This for example includes 1:1 left joins
4123 that are not part of the restriction specification (WHERE/HAVING) nor are
4124 a part of the query selection.
4126 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4132 =item Value: (0 | 1)
4136 When set to a true value, indicates that any rows fetched from joined has_many
4137 relationships are to be aggregated into the corresponding "parent" object. For
4138 example, the resultset:
4140 my $rs = $schema->resultset('CD')->search({}, {
4141 '+columns' => [ qw/ tracks.title tracks.position / ],
4146 While executing the following query:
4148 SELECT me.*, tracks.title, tracks.position
4150 LEFT JOIN track tracks
4151 ON tracks.cdid = me.cdid
4153 Will return only as many objects as there are rows in the CD source, even
4154 though the result of the query may span many rows. Each of these CD objects
4155 will in turn have multiple "Track" objects hidden behind the has_many
4156 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4157 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4158 product"), with each CD object containing exactly one of all fetched Track data.
4160 When a collapse is requested on a non-ordered resultset, an order by some
4161 unique part of the main source (the left-most table) is inserted automatically.
4162 This is done so that the resultset is allowed to be "lazy" - calling
4163 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4164 object with all of its related data.
4166 If an L</order_by> is already declared, and orders the resultset in a way that
4167 makes collapsing as described above impossible (e.g. C<< ORDER BY
4168 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4169 switch to "eager" mode and slurp the entire resultset before consturcting the
4170 first object returned by L</next>.
4172 Setting this attribute on a resultset that does not join any has_many
4173 relations is a no-op.
4175 For a more in-depth discussion, see L</PREFETCHING>.
4181 =item Value: ($rel_name | \@rel_names | \%rel_names)
4185 This attribute is a shorthand for specifying a L</join> spec, adding all
4186 columns from the joined related sources as L</+columns> and setting
4187 L</collapse> to a true value. For example, the following two queries are
4190 my $rs = $schema->resultset('Artist')->search({}, {
4191 prefetch => { cds => ['genre', 'tracks' ] },
4196 my $rs = $schema->resultset('Artist')->search({}, {
4197 join => { cds => ['genre', 'tracks' ] },
4201 { +{ "cds.$_" => "cds.$_" } }
4202 $schema->source('Artist')->related_source('cds')->columns
4205 { +{ "cds.genre.$_" => "genre.$_" } }
4206 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4209 { +{ "cds.tracks.$_" => "tracks.$_" } }
4210 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4215 Both producing the following SQL:
4217 SELECT me.artistid, me.name, me.rank, me.charfield,
4218 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4219 genre.genreid, genre.name,
4220 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4223 ON cds.artist = me.artistid
4224 LEFT JOIN genre genre
4225 ON genre.genreid = cds.genreid
4226 LEFT JOIN track tracks
4227 ON tracks.cd = cds.cdid
4228 ORDER BY me.artistid
4230 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4231 the arguments are properly merged and generally do the right thing. For
4232 example, you may want to do the following:
4234 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4235 { 'genre.genreid' => undef },
4237 join => { cds => 'genre' },
4242 Which generates the following SQL:
4244 SELECT me.artistid, me.name, me.rank, me.charfield,
4245 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4248 ON cds.artist = me.artistid
4249 LEFT JOIN genre genre
4250 ON genre.genreid = cds.genreid
4251 WHERE genre.genreid IS NULL
4252 ORDER BY me.artistid
4254 For a more in-depth discussion, see L</PREFETCHING>.
4260 =item Value: $source_alias
4264 Sets the source alias for the query. Normally, this defaults to C<me>, but
4265 nested search queries (sub-SELECTs) might need specific aliases set to
4266 reference inner queries. For example:
4269 ->related_resultset('CDs')
4270 ->related_resultset('Tracks')
4272 'track.id' => { -ident => 'none_search.id' },
4276 my $ids = $self->search({
4279 alias => 'none_search',
4280 group_by => 'none_search.id',
4281 })->get_column('id')->as_query;
4283 $self->search({ id => { -in => $ids } })
4285 This attribute is directly tied to L</current_source_alias>.
4295 Makes the resultset paged and specifies the page to retrieve. Effectively
4296 identical to creating a non-pages resultset and then calling ->page($page)
4299 If L</rows> attribute is not specified it defaults to 10 rows per page.
4301 When you have a paged resultset, L</count> will only return the number
4302 of rows in the page. To get the total, use the L</pager> and call
4303 C<total_entries> on it.
4313 Specifies the maximum number of rows for direct retrieval or the number of
4314 rows per page if the page attribute or method is used.
4320 =item Value: $offset
4324 Specifies the (zero-based) row number for the first row to be returned, or the
4325 of the first row of the first page if paging is used.
4327 =head2 software_limit
4331 =item Value: (0 | 1)
4335 When combined with L</rows> and/or L</offset> the generated SQL will not
4336 include any limit dialect stanzas. Instead the entire result will be selected
4337 as if no limits were specified, and DBIC will perform the limit locally, by
4338 artificially advancing and finishing the resulting L</cursor>.
4340 This is the recommended way of performing resultset limiting when no sane RDBMS
4341 implementation is available (e.g.
4342 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4343 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4349 =item Value: \@columns
4353 A arrayref of columns to group by. Can include columns of joined tables.
4355 group_by => [qw/ column1 column2 ... /]
4361 =item Value: $condition
4365 HAVING is a select statement attribute that is applied between GROUP BY and
4366 ORDER BY. It is applied to the after the grouping calculations have been
4369 having => { 'count_employee' => { '>=', 100 } }
4371 or with an in-place function in which case literal SQL is required:
4373 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4379 =item Value: (0 | 1)
4383 Set to 1 to group by all columns. If the resultset already has a group_by
4384 attribute, this setting is ignored and an appropriate warning is issued.
4390 Adds to the WHERE clause.
4392 # only return rows WHERE deleted IS NULL for all searches
4393 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4395 Can be overridden by passing C<< { where => undef } >> as an attribute
4398 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4404 Set to 1 to cache search results. This prevents extra SQL queries if you
4405 revisit rows in your ResultSet:
4407 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4409 while( my $artist = $resultset->next ) {
4413 $rs->first; # without cache, this would issue a query
4415 By default, searches are not cached.
4417 For more examples of using these attributes, see
4418 L<DBIx::Class::Manual::Cookbook>.
4424 =item Value: ( 'update' | 'shared' | \$scalar )
4428 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4429 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4434 DBIx::Class supports arbitrary related data prefetching from multiple related
4435 sources. Any combination of relationship types and column sets are supported.
4436 If L<collapsing|/collapse> is requested, there is an additional requirement of
4437 selecting enough data to make every individual object uniquely identifiable.
4439 Here are some more involved examples, based on the following relationship map:
4442 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4443 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4444 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4446 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4448 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4452 my $rs = $schema->resultset('Tag')->search(
4461 The initial search results in SQL like the following:
4463 SELECT tag.*, cd.*, artist.* FROM tag
4464 JOIN cd ON tag.cd = cd.cdid
4465 JOIN artist ON cd.artist = artist.artistid
4467 L<DBIx::Class> has no need to go back to the database when we access the
4468 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4471 Simple prefetches will be joined automatically, so there is no need
4472 for a C<join> attribute in the above search.
4474 The L</prefetch> attribute can be used with any of the relationship types
4475 and multiple prefetches can be specified together. Below is a more complex
4476 example that prefetches a CD's artist, its liner notes (if present),
4477 the cover image, the tracks on that CD, and the guests on those
4480 my $rs = $schema->resultset('CD')->search(
4484 { artist => 'record_label'}, # belongs_to => belongs_to
4485 'liner_note', # might_have
4486 'cover_image', # has_one
4487 { tracks => 'guests' }, # has_many => has_many
4492 This will produce SQL like the following:
4494 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4498 ON artist.artistid = me.artistid
4499 JOIN record_label record_label
4500 ON record_label.labelid = artist.labelid
4501 LEFT JOIN track tracks
4502 ON tracks.cdid = me.cdid
4503 LEFT JOIN guest guests
4504 ON guests.trackid = track.trackid
4505 LEFT JOIN liner_notes liner_note
4506 ON liner_note.cdid = me.cdid
4507 JOIN cd_artwork cover_image
4508 ON cover_image.cdid = me.cdid
4511 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4512 C<tracks>, and C<guests> of the CD will all be available through the
4513 relationship accessors without the need for additional queries to the
4518 Prefetch does a lot of deep magic. As such, it may not behave exactly
4519 as you might expect.
4525 Prefetch uses the L</cache> to populate the prefetched relationships. This
4526 may or may not be what you want.
4530 If you specify a condition on a prefetched relationship, ONLY those
4531 rows that match the prefetched condition will be fetched into that relationship.
4532 This means that adding prefetch to a search() B<may alter> what is returned by
4533 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4535 my $artist_rs = $schema->resultset('Artist')->search({
4541 my $count = $artist_rs->first->cds->count;
4543 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4545 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4547 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4549 That cmp_ok() may or may not pass depending on the datasets involved. In other
4550 words the C<WHERE> condition would apply to the entire dataset, just like
4551 it would in regular SQL. If you want to add a condition only to the "right side"
4552 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4553 condition|DBIx::Class::Relationship::Base/condition>
4557 =head1 DBIC BIND VALUES
4559 Because DBIC may need more information to bind values than just the column name
4560 and value itself, it uses a special format for both passing and receiving bind
4561 values. Each bind value should be composed of an arrayref of
4562 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4568 If present (in any form), this is what is being passed directly to bind_param.
4569 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4570 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4572 If this is specified, all other bind options described below are ignored.
4576 If present, this is used to infer the actual bind attribute by passing to
4577 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4578 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4580 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4581 currently drivers are expected to "Do the Right Thing" when given a common
4582 datatype name. (Not ideal, but that's what we got at this point.)
4586 Currently used to correctly allocate buffers for bind_param_inout().
4587 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4588 or to a sensible value based on the "data_type".
4592 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4593 explicitly specified they are never overriden). Also used by some weird DBDs,
4594 where the column name should be available at bind_param time (e.g. Oracle).
4598 For backwards compatibility and convenience, the following shortcuts are
4601 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4602 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4603 [ undef, $val ] === [ {}, $val ]
4605 =head1 AUTHOR AND CONTRIBUTORS
4607 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4611 You may distribute this code under the same terms as Perl itself.