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 $self->_construct_objects->[0];
1087 # Recursively collapse the query, accumulating values for each column.
1089 sub _collapse_query {
1090 my ($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_objects}}) if @{ $self->{stashed_objects}||[] };
1252 $self->{stashed_objects} = $self->_construct_objects
1255 return shift @{$self->{stashed_objects}};
1258 # Constructs as many objects 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 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 $fetch_all
1270 # was requested (there is no other way to collapse except for an
1272 # * If no collapse is requested - just get the next row, construct and
1274 sub _construct_objects {
1275 my ($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_objects. Not regrowing the array twice matters a lot...
1291 # a suprising 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 breach, got to be a better way
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};
1371 $self->{_result_inflator}{is_hri} = do { ( $inflator_cref == (
1372 require DBIx::Class::ResultClass::HashRefInflator
1374 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1376 } unless defined $self->{_result_inflator}{is_hri};
1378 if ($attrs->{_single_resultclass_inflation}) {
1379 # construct a much simpler array->hash folder for the one-table cases right here
1380 if ($self->{_result_inflator}{is_hri}) {
1381 for my $r (@$rows) {
1382 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1385 # FIXME SUBOPTIMAL this is a very very very hot spot
1386 # while rather optimal we can *still* do much better, by
1387 # building a smarter Row::inflate_result(), and
1388 # switch to feeding it data via a much leaner interface
1390 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1391 # this particular resultset size
1392 elsif (@$rows < 60) {
1393 for my $r (@$rows) {
1394 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1399 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1400 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1404 # Special-case multi-object HRI (we always prune)
1405 elsif ($self->{_result_inflator}{is_hri}) {
1406 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1408 inflate_map => $infmap,
1409 selection => $attrs->{select},
1410 collapse => $attrs->{collapse},
1411 premultiplied => $attrs->{_main_source_premultiplied},
1413 }) )->($rows, @extra_collapser_args);
1415 # Regular multi-object
1418 ( $self->{_row_parser}{classic} ||= $rsrc->_mk_row_parser({
1420 inflate_map => $infmap,
1421 selection => $attrs->{select},
1422 collapse => $attrs->{collapse},
1423 premultiplied => $attrs->{_main_source_premultiplied},
1424 }) )->($rows, @extra_collapser_args);
1426 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1430 if ($attrs->{record_filter}) {
1431 $_ = $attrs->{record_filter}->($_) for @$rows;
1437 =head2 result_source
1441 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1443 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1447 An accessor for the primary ResultSource object from which this ResultSet
1454 =item Arguments: $result_class?
1456 =item Return Value: $result_class
1460 An accessor for the class to use when creating result objects. Defaults to
1461 C<< result_source->result_class >> - which in most cases is the name of the
1462 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1464 Note that changing the result_class will also remove any components
1465 that were originally loaded in the source class via
1466 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1467 in the original source class will not run.
1472 my ($self, $result_class) = @_;
1473 if ($result_class) {
1475 unless (ref $result_class) { # don't fire this for an object
1476 $self->ensure_class_loaded($result_class);
1478 $self->_result_class($result_class);
1479 # THIS LINE WOULD BE A BUG - this accessor specifically exists to
1480 # permit the user to set result class on one result set only; it only
1481 # chains if provided to search()
1482 #$self->{attrs}{result_class} = $result_class if ref $self;
1484 delete $self->{_result_inflator};
1486 $self->_result_class;
1493 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1495 =item Return Value: $count
1499 Performs an SQL C<COUNT> with the same query as the resultset was built
1500 with to find the number of elements. Passing arguments is equivalent to
1501 C<< $rs->search ($cond, \%attrs)->count >>
1507 return $self->search(@_)->count if @_ and defined $_[0];
1508 return scalar @{ $self->get_cache } if $self->get_cache;
1510 my $attrs = { %{ $self->_resolved_attrs } };
1512 # this is a little optimization - it is faster to do the limit
1513 # adjustments in software, instead of a subquery
1514 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1517 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1518 $crs = $self->_count_subq_rs ($attrs);
1521 $crs = $self->_count_rs ($attrs);
1523 my $count = $crs->next;
1525 $count -= $offset if $offset;
1526 $count = $rows if $rows and $rows < $count;
1527 $count = 0 if ($count < 0);
1536 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1538 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1542 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1543 This can be very handy for subqueries:
1545 ->search( { amount => $some_rs->count_rs->as_query } )
1547 As with regular resultsets the SQL query will be executed only after
1548 the resultset is accessed via L</next> or L</all>. That would return
1549 the same single value obtainable via L</count>.
1555 return $self->search(@_)->count_rs if @_;
1557 # this may look like a lack of abstraction (count() does about the same)
1558 # but in fact an _rs *must* use a subquery for the limits, as the
1559 # software based limiting can not be ported if this $rs is to be used
1560 # in a subquery itself (i.e. ->as_query)
1561 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1562 return $self->_count_subq_rs;
1565 return $self->_count_rs;
1570 # returns a ResultSetColumn object tied to the count query
1573 my ($self, $attrs) = @_;
1575 my $rsrc = $self->result_source;
1576 $attrs ||= $self->_resolved_attrs;
1578 my $tmp_attrs = { %$attrs };
1579 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1580 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1582 # overwrite the selector (supplied by the storage)
1583 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1584 $tmp_attrs->{as} = 'count';
1586 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1592 # same as above but uses a subquery
1594 sub _count_subq_rs {
1595 my ($self, $attrs) = @_;
1597 my $rsrc = $self->result_source;
1598 $attrs ||= $self->_resolved_attrs;
1600 my $sub_attrs = { %$attrs };
1601 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1602 delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/};
1604 # if we multi-prefetch we group_by something unique, as this is what we would
1605 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1606 if ( $attrs->{collapse} ) {
1607 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1608 $rsrc->_identifying_column_set || $self->throw_exception(
1609 'Unable to construct a unique group_by criteria properly collapsing the '
1610 . 'has_many prefetch before count()'
1615 # Calculate subquery selector
1616 if (my $g = $sub_attrs->{group_by}) {
1618 my $sql_maker = $rsrc->storage->sql_maker;
1620 # necessary as the group_by may refer to aliased functions
1622 for my $sel (@{$attrs->{select}}) {
1623 $sel_index->{$sel->{-as}} = $sel
1624 if (ref $sel eq 'HASH' and $sel->{-as});
1627 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1628 # also look for named aggregates referred in the having clause
1629 # having often contains scalarrefs - thus parse it out entirely
1631 if ($attrs->{having}) {
1632 local $sql_maker->{having_bind};
1633 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1634 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1635 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1636 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1637 # if we don't unset it we screw up retarded but unfortunately working
1638 # 'MAX(foo.bar)' => { '>', 3 }
1639 $sql_maker->{name_sep} = '';
1642 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1644 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1647 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1648 # and if all fails for an utterly naive quoted scalar-with-function
1649 while ($having_sql =~ /
1650 $rquote $sep $lquote (.+?) $rquote
1652 [\s,] \w+ \. (\w+) [\s,]
1654 [\s,] $lquote (.+?) $rquote [\s,]
1656 my $part = $1 || $2 || $3; # one of them matched if we got here
1657 unless ($seen_having{$part}++) {
1664 my $colpiece = $sel_index->{$_} || $_;
1666 # unqualify join-based group_by's. Arcane but possible query
1667 # also horrible horrible hack to alias a column (not a func.)
1668 # (probably need to introduce SQLA syntax)
1669 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1672 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1674 push @{$sub_attrs->{select}}, $colpiece;
1678 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1679 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1682 return $rsrc->resultset_class
1683 ->new ($rsrc, $sub_attrs)
1685 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1686 ->get_column ('count');
1690 =head2 count_literal
1692 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1693 should only be used in that context. See L</search_literal> for further info.
1697 =item Arguments: $sql_fragment, @standalone_bind_values
1699 =item Return Value: $count
1703 Counts the results in a literal query. Equivalent to calling L</search_literal>
1704 with the passed arguments, then L</count>.
1708 sub count_literal { shift->search_literal(@_)->count; }
1714 =item Arguments: none
1716 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1720 Returns all elements in the resultset.
1727 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1730 delete @{$self}{qw/stashed_rows stashed_objects/};
1732 if (my $c = $self->get_cache) {
1736 $self->cursor->reset;
1738 my $objs = $self->_construct_objects('fetch_all') || [];
1740 $self->set_cache($objs) if $self->{attrs}{cache};
1749 =item Arguments: none
1751 =item Return Value: $self
1755 Resets the resultset's cursor, so you can iterate through the elements again.
1756 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1764 delete @{$self}{qw/stashed_rows stashed_objects/};
1765 $self->{all_cache_position} = 0;
1766 $self->cursor->reset;
1774 =item Arguments: none
1776 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1780 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1781 an object for the first result (or C<undef> if the resultset is empty).
1786 return $_[0]->reset->next;
1792 # Determines whether and what type of subquery is required for the $rs operation.
1793 # If grouping is necessary either supplies its own, or verifies the current one
1794 # After all is done delegates to the proper storage method.
1796 sub _rs_update_delete {
1797 my ($self, $op, $values) = @_;
1799 my $rsrc = $self->result_source;
1800 my $storage = $rsrc->schema->storage;
1802 my $attrs = { %{$self->_resolved_attrs} };
1804 my $join_classifications;
1805 my $existing_group_by = delete $attrs->{group_by};
1807 # do we need a subquery for any reason?
1809 defined $existing_group_by
1811 # if {from} is unparseable wrap a subq
1812 ref($attrs->{from}) ne 'ARRAY'
1814 # limits call for a subq
1815 $self->_has_resolved_attr(qw/rows offset/)
1818 # simplify the joinmap, so we can further decide if a subq is necessary
1819 if (!$needs_subq and @{$attrs->{from}} > 1) {
1820 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1822 # check if there are any joins left after the prune
1823 if ( @{$attrs->{from}} > 1 ) {
1824 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1825 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1831 # any non-pruneable joins imply subq
1832 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1836 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1838 (ref $attrs->{from}[0]) ne 'HASH'
1840 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1844 # do we need anything like a subquery?
1845 if (! $needs_subq) {
1846 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1847 # a condition containing 'me' or other table prefixes will not work
1848 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1850 my $sqla = $rsrc->storage->sql_maker;
1851 local $sqla->{_dequalify_idents} = 1;
1852 \[ $sqla->_recurse_where($self->{cond}) ];
1856 # we got this far - means it is time to wrap a subquery
1857 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1859 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1865 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1866 delete $attrs->{$_} for qw/collapse select _prefetch_selector_range as/;
1867 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1868 $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins
1869 my $subrs = (ref $self)->new($rsrc, $attrs);
1871 if (@$idcols == 1) {
1872 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1874 elsif ($storage->_use_multicolumn_in) {
1875 # no syntax for calling this properly yet
1876 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1877 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1878 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1883 # if all else fails - get all primary keys and operate over a ORed set
1884 # wrap in a transaction for consistency
1885 # this is where the group_by/multiplication starts to matter
1889 keys %{ $join_classifications->{multiplying} || {} }
1891 # make sure if there is a supplied group_by it matches the columns compiled above
1892 # perfectly. Anything else can not be sanely executed on most databases so croak
1893 # right then and there
1894 if ($existing_group_by) {
1895 my @current_group_by = map
1896 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1901 join ("\x00", sort @current_group_by)
1903 join ("\x00", sort @{$attrs->{columns}} )
1905 $self->throw_exception (
1906 "You have just attempted a $op operation on a resultset which does group_by"
1907 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1908 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1909 . ' kind of queries. Please retry the operation with a modified group_by or'
1910 . ' without using one at all.'
1915 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1918 $guard = $storage->txn_scope_guard;
1921 for my $row ($subrs->cursor->all) {
1923 { $idcols->[$_] => $row->[$_] }
1930 my $res = $storage->$op (
1932 $op eq 'update' ? $values : (),
1936 $guard->commit if $guard;
1945 =item Arguments: \%values
1947 =item Return Value: $underlying_storage_rv
1951 Sets the specified columns in the resultset to the supplied values in a
1952 single query. Note that this will not run any accessor/set_column/update
1953 triggers, nor will it update any result object instances derived from this
1954 resultset (this includes the contents of the L<resultset cache|/set_cache>
1955 if any). See L</update_all> if you need to execute any on-update
1956 triggers or cascades defined either by you or a
1957 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1959 The return value is a pass through of what the underlying
1960 storage backend returned, and may vary. See L<DBI/execute> for the most
1965 Note that L</update> does not process/deflate any of the values passed in.
1966 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1967 ensure manually that any value passed to this method will stringify to
1968 something the RDBMS knows how to deal with. A notable example is the
1969 handling of L<DateTime> objects, for more info see:
1970 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1975 my ($self, $values) = @_;
1976 $self->throw_exception('Values for update must be a hash')
1977 unless ref $values eq 'HASH';
1979 return $self->_rs_update_delete ('update', $values);
1986 =item Arguments: \%values
1988 =item Return Value: 1
1992 Fetches all objects and updates them one at a time via
1993 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
1994 triggers, while L</update> will not.
1999 my ($self, $values) = @_;
2000 $self->throw_exception('Values for update_all must be a hash')
2001 unless ref $values eq 'HASH';
2003 my $guard = $self->result_source->schema->txn_scope_guard;
2004 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2013 =item Arguments: none
2015 =item Return Value: $underlying_storage_rv
2019 Deletes the rows matching this resultset in a single query. Note that this
2020 will not run any delete triggers, nor will it alter the
2021 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2022 derived from this resultset (this includes the contents of the
2023 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2024 execute any on-delete triggers or cascades defined either by you or a
2025 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2027 The return value is a pass through of what the underlying storage backend
2028 returned, and may vary. See L<DBI/execute> for the most common case.
2034 $self->throw_exception('delete does not accept any arguments')
2037 return $self->_rs_update_delete ('delete');
2044 =item Arguments: none
2046 =item Return Value: 1
2050 Fetches all objects and deletes them one at a time via
2051 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2052 triggers, while L</delete> will not.
2058 $self->throw_exception('delete_all does not accept any arguments')
2061 my $guard = $self->result_source->schema->txn_scope_guard;
2062 $_->delete for $self->all;
2071 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2073 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2077 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2084 The context of this method call has an important effect on what is
2085 submitted to storage. In void context data is fed directly to fastpath
2086 insertion routines provided by the underlying storage (most often
2087 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2088 L<insert|DBIx::Class::Row/insert> calls on the
2089 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2090 augmentation of these methods provided by components. For example if you
2091 are using something like L<DBIx::Class::UUIDColumns> to create primary
2092 keys for you, you will find that your PKs are empty. In this case you
2093 will have to explicitly force scalar or list context in order to create
2098 In non-void (scalar or list) context, this method is simply a wrapper
2099 for L</create>. Depending on list or scalar context either a list of
2100 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2101 containing these objects is returned.
2103 When supplying data in "arrayref of arrayrefs" invocation style, the
2104 first element should be a list of column names and each subsequent
2105 element should be a data value in the earlier specified column order.
2108 $Arstist_rs->populate([
2109 [ qw( artistid name ) ],
2110 [ 100, 'A Formally Unknown Singer' ],
2111 [ 101, 'A singer that jumped the shark two albums ago' ],
2112 [ 102, 'An actually cool singer' ],
2115 For the arrayref of hashrefs style each hashref should be a structure
2116 suitable for passing to L</create>. Multi-create is also permitted with
2119 $schema->resultset("Artist")->populate([
2120 { artistid => 4, name => 'Manufactured Crap', cds => [
2121 { title => 'My First CD', year => 2006 },
2122 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2125 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2126 { title => 'My parents sold me to a record company', year => 2005 },
2127 { title => 'Why Am I So Ugly?', year => 2006 },
2128 { title => 'I Got Surgery and am now Popular', year => 2007 }
2133 If you attempt a void-context multi-create as in the example above (each
2134 Artist also has the related list of CDs), and B<do not> supply the
2135 necessary autoinc foreign key information, this method will proxy to the
2136 less efficient L</create>, and then throw the Result objects away. In this
2137 case there are obviously no benefits to using this method over L</create>.
2144 # cruft placed in standalone method
2145 my $data = $self->_normalize_populate_args(@_);
2147 return unless @$data;
2149 if(defined wantarray) {
2150 my @created = map { $self->create($_) } @$data;
2151 return wantarray ? @created : \@created;
2154 my $first = $data->[0];
2156 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2157 # it relationship data
2158 my (@rels, @columns);
2159 my $rsrc = $self->result_source;
2160 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2161 for (keys %$first) {
2162 my $ref = ref $first->{$_};
2163 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2169 my @pks = $rsrc->primary_columns;
2171 ## do the belongs_to relationships
2172 foreach my $index (0..$#$data) {
2174 # delegate to create() for any dataset without primary keys with specified relationships
2175 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2177 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2178 my @ret = $self->populate($data);
2184 foreach my $rel (@rels) {
2185 next unless ref $data->[$index]->{$rel} eq "HASH";
2186 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2187 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2188 my $related = $result->result_source->_resolve_condition(
2189 $reverse_relinfo->{cond},
2195 delete $data->[$index]->{$rel};
2196 $data->[$index] = {%{$data->[$index]}, %$related};
2198 push @columns, keys %$related if $index == 0;
2202 ## inherit the data locked in the conditions of the resultset
2203 my ($rs_data) = $self->_merge_with_rscond({});
2204 delete @{$rs_data}{@columns};
2206 ## do bulk insert on current row
2207 $rsrc->storage->insert_bulk(
2209 [@columns, keys %$rs_data],
2210 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2213 ## do the has_many relationships
2214 foreach my $item (@$data) {
2218 foreach my $rel (@rels) {
2219 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2221 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2223 my $child = $main_row->$rel;
2225 my $related = $child->result_source->_resolve_condition(
2226 $rels->{$rel}{cond},
2232 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2233 my @populate = map { {%$_, %$related} } @rows_to_add;
2235 $child->populate( \@populate );
2242 # populate() argumnets went over several incarnations
2243 # What we ultimately support is AoH
2244 sub _normalize_populate_args {
2245 my ($self, $arg) = @_;
2247 if (ref $arg eq 'ARRAY') {
2251 elsif (ref $arg->[0] eq 'HASH') {
2254 elsif (ref $arg->[0] eq 'ARRAY') {
2256 my @colnames = @{$arg->[0]};
2257 foreach my $values (@{$arg}[1 .. $#$arg]) {
2258 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2264 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2271 =item Arguments: none
2273 =item Return Value: L<$pager|Data::Page>
2277 Returns a L<Data::Page> object for the current resultset. Only makes
2278 sense for queries with a C<page> attribute.
2280 To get the full count of entries for a paged resultset, call
2281 C<total_entries> on the L<Data::Page> object.
2288 return $self->{pager} if $self->{pager};
2290 my $attrs = $self->{attrs};
2291 if (!defined $attrs->{page}) {
2292 $self->throw_exception("Can't create pager for non-paged rs");
2294 elsif ($attrs->{page} <= 0) {
2295 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2297 $attrs->{rows} ||= 10;
2299 # throw away the paging flags and re-run the count (possibly
2300 # with a subselect) to get the real total count
2301 my $count_attrs = { %$attrs };
2302 delete @{$count_attrs}{qw/rows offset page pager/};
2304 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2306 require DBIx::Class::ResultSet::Pager;
2307 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2308 sub { $total_rs->count }, #lazy-get the total
2310 $self->{attrs}{page},
2318 =item Arguments: $page_number
2320 =item Return Value: L<$resultset|/search>
2324 Returns a resultset for the $page_number page of the resultset on which page
2325 is called, where each page contains a number of rows equal to the 'rows'
2326 attribute set on the resultset (10 by default).
2331 my ($self, $page) = @_;
2332 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2339 =item Arguments: \%col_data
2341 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2345 Creates a new result object in the resultset's result class and returns
2346 it. The row is not inserted into the database at this point, call
2347 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2348 will tell you whether the result object has been inserted or not.
2350 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2355 my ($self, $values) = @_;
2357 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2360 $self->throw_exception( "new_result expects a hashref" )
2361 unless (ref $values eq 'HASH');
2363 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2365 my $new = $self->result_class->new({
2367 ( @$cols_from_relations
2368 ? (-cols_from_relations => $cols_from_relations)
2371 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2375 reftype($new) eq 'HASH'
2381 carp_unique (sprintf (
2382 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2383 $self->result_class,
2390 # _merge_with_rscond
2392 # Takes a simple hash of K/V data and returns its copy merged with the
2393 # condition already present on the resultset. Additionally returns an
2394 # arrayref of value/condition names, which were inferred from related
2395 # objects (this is needed for in-memory related objects)
2396 sub _merge_with_rscond {
2397 my ($self, $data) = @_;
2399 my (%new_data, @cols_from_relations);
2401 my $alias = $self->{attrs}{alias};
2403 if (! defined $self->{cond}) {
2404 # just massage $data below
2406 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2407 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2408 @cols_from_relations = keys %new_data;
2410 elsif (ref $self->{cond} ne 'HASH') {
2411 $self->throw_exception(
2412 "Can't abstract implicit construct, resultset condition not a hash"
2416 # precendence must be given to passed values over values inherited from
2417 # the cond, so the order here is important.
2418 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2419 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2421 while ( my($col, $value) = each %implied ) {
2422 my $vref = ref $value;
2428 (keys %$value)[0] eq '='
2430 $new_data{$col} = $value->{'='};
2432 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2433 $new_data{$col} = $value;
2440 %{ $self->_remove_alias($data, $alias) },
2443 return (\%new_data, \@cols_from_relations);
2446 # _has_resolved_attr
2448 # determines if the resultset defines at least one
2449 # of the attributes supplied
2451 # used to determine if a subquery is neccessary
2453 # supports some virtual attributes:
2455 # This will scan for any joins being present on the resultset.
2456 # It is not a mere key-search but a deep inspection of {from}
2459 sub _has_resolved_attr {
2460 my ($self, @attr_names) = @_;
2462 my $attrs = $self->_resolved_attrs;
2466 for my $n (@attr_names) {
2467 if (grep { $n eq $_ } (qw/-join/) ) {
2468 $extra_checks{$n}++;
2472 my $attr = $attrs->{$n};
2474 next if not defined $attr;
2476 if (ref $attr eq 'HASH') {
2477 return 1 if keys %$attr;
2479 elsif (ref $attr eq 'ARRAY') {
2487 # a resolved join is expressed as a multi-level from
2489 $extra_checks{-join}
2491 ref $attrs->{from} eq 'ARRAY'
2493 @{$attrs->{from}} > 1
2501 # Recursively collapse the condition.
2503 sub _collapse_cond {
2504 my ($self, $cond, $collapsed) = @_;
2508 if (ref $cond eq 'ARRAY') {
2509 foreach my $subcond (@$cond) {
2510 next unless ref $subcond; # -or
2511 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2514 elsif (ref $cond eq 'HASH') {
2515 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2516 foreach my $subcond (@{$cond->{-and}}) {
2517 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2521 foreach my $col (keys %$cond) {
2522 my $value = $cond->{$col};
2523 $collapsed->{$col} = $value;
2533 # Remove the specified alias from the specified query hash. A copy is made so
2534 # the original query is not modified.
2537 my ($self, $query, $alias) = @_;
2539 my %orig = %{ $query || {} };
2542 foreach my $key (keys %orig) {
2544 $unaliased{$key} = $orig{$key};
2547 $unaliased{$1} = $orig{$key}
2548 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2558 =item Arguments: none
2560 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2564 Returns the SQL query and bind vars associated with the invocant.
2566 This is generally used as the RHS for a subquery.
2573 my $attrs = { %{ $self->_resolved_attrs } };
2578 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2579 # $sql also has no wrapping parenthesis in list ctx
2581 my $sqlbind = $self->result_source->storage
2582 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2591 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2593 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2597 my $artist = $schema->resultset('Artist')->find_or_new(
2598 { artist => 'fred' }, { key => 'artists' });
2600 $cd->cd_to_producer->find_or_new({ producer => $producer },
2601 { key => 'primary });
2603 Find an existing record from this resultset using L</find>. if none exists,
2604 instantiate a new result object and return it. The object will not be saved
2605 into your storage until you call L<DBIx::Class::Row/insert> on it.
2607 You most likely want this method when looking for existing rows using a unique
2608 constraint that is not the primary key, or looking for related rows.
2610 If you want objects to be saved immediately, use L</find_or_create> instead.
2612 B<Note>: Make sure to read the documentation of L</find> and understand the
2613 significance of the C<key> attribute, as its lack may skew your search, and
2614 subsequently result in spurious new objects.
2616 B<Note>: Take care when using C<find_or_new> with a table having
2617 columns with default values that you intend to be automatically
2618 supplied by the database (e.g. an auto_increment primary key column).
2619 In normal usage, the value of such columns should NOT be included at
2620 all in the call to C<find_or_new>, even when set to C<undef>.
2626 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2627 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2628 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2631 return $self->new_result($hash);
2638 =item Arguments: \%col_data
2640 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2644 Attempt to create a single new row or a row with multiple related rows
2645 in the table represented by the resultset (and related tables). This
2646 will not check for duplicate rows before inserting, use
2647 L</find_or_create> to do that.
2649 To create one row for this resultset, pass a hashref of key/value
2650 pairs representing the columns of the table and the values you wish to
2651 store. If the appropriate relationships are set up, foreign key fields
2652 can also be passed an object representing the foreign row, and the
2653 value will be set to its primary key.
2655 To create related objects, pass a hashref of related-object column values
2656 B<keyed on the relationship name>. If the relationship is of type C<multi>
2657 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2658 The process will correctly identify columns holding foreign keys, and will
2659 transparently populate them from the keys of the corresponding relation.
2660 This can be applied recursively, and will work correctly for a structure
2661 with an arbitrary depth and width, as long as the relationships actually
2662 exists and the correct column data has been supplied.
2664 Instead of hashrefs of plain related data (key/value pairs), you may
2665 also pass new or inserted objects. New objects (not inserted yet, see
2666 L</new_result>), will be inserted into their appropriate tables.
2668 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2670 Example of creating a new row.
2672 $person_rs->create({
2673 name=>"Some Person",
2674 email=>"somebody@someplace.com"
2677 Example of creating a new row and also creating rows in a related C<has_many>
2678 or C<has_one> resultset. Note Arrayref.
2681 { artistid => 4, name => 'Manufactured Crap', cds => [
2682 { title => 'My First CD', year => 2006 },
2683 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2688 Example of creating a new row and also creating a row in a related
2689 C<belongs_to> resultset. Note Hashref.
2692 title=>"Music for Silly Walks",
2695 name=>"Silly Musician",
2703 When subclassing ResultSet never attempt to override this method. Since
2704 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2705 lot of the internals simply never call it, so your override will be
2706 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2707 or L<DBIx::Class::Row/insert> depending on how early in the
2708 L</create> process you need to intervene. See also warning pertaining to
2716 my ($self, $attrs) = @_;
2717 $self->throw_exception( "create needs a hashref" )
2718 unless ref $attrs eq 'HASH';
2719 return $self->new_result($attrs)->insert;
2722 =head2 find_or_create
2726 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2728 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2732 $cd->cd_to_producer->find_or_create({ producer => $producer },
2733 { key => 'primary' });
2735 Tries to find a record based on its primary key or unique constraints; if none
2736 is found, creates one and returns that instead.
2738 my $cd = $schema->resultset('CD')->find_or_create({
2740 artist => 'Massive Attack',
2741 title => 'Mezzanine',
2745 Also takes an optional C<key> attribute, to search by a specific key or unique
2746 constraint. For example:
2748 my $cd = $schema->resultset('CD')->find_or_create(
2750 artist => 'Massive Attack',
2751 title => 'Mezzanine',
2753 { key => 'cd_artist_title' }
2756 B<Note>: Make sure to read the documentation of L</find> and understand the
2757 significance of the C<key> attribute, as its lack may skew your search, and
2758 subsequently result in spurious row creation.
2760 B<Note>: Because find_or_create() reads from the database and then
2761 possibly inserts based on the result, this method is subject to a race
2762 condition. Another process could create a record in the table after
2763 the find has completed and before the create has started. To avoid
2764 this problem, use find_or_create() inside a transaction.
2766 B<Note>: Take care when using C<find_or_create> with a table having
2767 columns with default values that you intend to be automatically
2768 supplied by the database (e.g. an auto_increment primary key column).
2769 In normal usage, the value of such columns should NOT be included at
2770 all in the call to C<find_or_create>, even when set to C<undef>.
2772 See also L</find> and L</update_or_create>. For information on how to declare
2773 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2775 If you need to know if an existing row was found or a new one created use
2776 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2777 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2780 my $cd = $schema->resultset('CD')->find_or_new({
2782 artist => 'Massive Attack',
2783 title => 'Mezzanine',
2787 if( !$cd->in_storage ) {
2794 sub find_or_create {
2796 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2797 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2798 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2801 return $self->create($hash);
2804 =head2 update_or_create
2808 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2810 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2814 $resultset->update_or_create({ col => $val, ... });
2816 Like L</find_or_create>, but if a row is found it is immediately updated via
2817 C<< $found_row->update (\%col_data) >>.
2820 Takes an optional C<key> attribute to search on a specific unique constraint.
2823 # In your application
2824 my $cd = $schema->resultset('CD')->update_or_create(
2826 artist => 'Massive Attack',
2827 title => 'Mezzanine',
2830 { key => 'cd_artist_title' }
2833 $cd->cd_to_producer->update_or_create({
2834 producer => $producer,
2840 B<Note>: Make sure to read the documentation of L</find> and understand the
2841 significance of the C<key> attribute, as its lack may skew your search, and
2842 subsequently result in spurious row creation.
2844 B<Note>: Take care when using C<update_or_create> with a table having
2845 columns with default values that you intend to be automatically
2846 supplied by the database (e.g. an auto_increment primary key column).
2847 In normal usage, the value of such columns should NOT be included at
2848 all in the call to C<update_or_create>, even when set to C<undef>.
2850 See also L</find> and L</find_or_create>. For information on how to declare
2851 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2853 If you need to know if an existing row was updated or a new one created use
2854 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2855 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2860 sub update_or_create {
2862 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2863 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2865 my $row = $self->find($cond, $attrs);
2867 $row->update($cond);
2871 return $self->create($cond);
2874 =head2 update_or_new
2878 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2880 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2884 $resultset->update_or_new({ col => $val, ... });
2886 Like L</find_or_new> but if a row is found it is immediately updated via
2887 C<< $found_row->update (\%col_data) >>.
2891 # In your application
2892 my $cd = $schema->resultset('CD')->update_or_new(
2894 artist => 'Massive Attack',
2895 title => 'Mezzanine',
2898 { key => 'cd_artist_title' }
2901 if ($cd->in_storage) {
2902 # the cd was updated
2905 # the cd is not yet in the database, let's insert it
2909 B<Note>: Make sure to read the documentation of L</find> and understand the
2910 significance of the C<key> attribute, as its lack may skew your search, and
2911 subsequently result in spurious new objects.
2913 B<Note>: Take care when using C<update_or_new> with a table having
2914 columns with default values that you intend to be automatically
2915 supplied by the database (e.g. an auto_increment primary key column).
2916 In normal usage, the value of such columns should NOT be included at
2917 all in the call to C<update_or_new>, even when set to C<undef>.
2919 See also L</find>, L</find_or_create> and L</find_or_new>.
2925 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2926 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2928 my $row = $self->find( $cond, $attrs );
2929 if ( defined $row ) {
2930 $row->update($cond);
2934 return $self->new_result($cond);
2941 =item Arguments: none
2943 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2947 Gets the contents of the cache for the resultset, if the cache is set.
2949 The cache is populated either by using the L</prefetch> attribute to
2950 L</search> or by calling L</set_cache>.
2962 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2964 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2968 Sets the contents of the cache for the resultset. Expects an arrayref
2969 of objects of the same class as those produced by the resultset. Note that
2970 if the cache is set, the resultset will return the cached objects rather
2971 than re-querying the database even if the cache attr is not set.
2973 The contents of the cache can also be populated by using the
2974 L</prefetch> attribute to L</search>.
2979 my ( $self, $data ) = @_;
2980 $self->throw_exception("set_cache requires an arrayref")
2981 if defined($data) && (ref $data ne 'ARRAY');
2982 $self->{all_cache} = $data;
2989 =item Arguments: none
2991 =item Return Value: undef
2995 Clears the cache for the resultset.
3000 shift->set_cache(undef);
3007 =item Arguments: none
3009 =item Return Value: true, if the resultset has been paginated
3017 return !!$self->{attrs}{page};
3024 =item Arguments: none
3026 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3034 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3037 =head2 related_resultset
3041 =item Arguments: $rel_name
3043 =item Return Value: L<$resultset|/search>
3047 Returns a related resultset for the supplied relationship name.
3049 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3053 sub related_resultset {
3054 my ($self, $rel) = @_;
3056 return $self->{related_resultsets}{$rel} ||= do {
3057 my $rsrc = $self->result_source;
3058 my $rel_info = $rsrc->relationship_info($rel);
3060 $self->throw_exception(
3061 "search_related: result source '" . $rsrc->source_name .
3062 "' has no such relationship $rel")
3065 my $attrs = $self->_chain_relationship($rel);
3067 my $join_count = $attrs->{seen_join}{$rel};
3069 my $alias = $self->result_source->storage
3070 ->relname_to_table_alias($rel, $join_count);
3072 # since this is search_related, and we already slid the select window inwards
3073 # (the select/as attrs were deleted in the beginning), we need to flip all
3074 # left joins to inner, so we get the expected results
3075 # read the comment on top of the actual function to see what this does
3076 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3079 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3080 delete @{$attrs}{qw(result_class alias)};
3084 if (my $cache = $self->get_cache) {
3085 $related_cache = [ map
3086 { @{$_->related_resultset($rel)->get_cache||[]} }
3091 my $rel_source = $rsrc->related_source($rel);
3095 # The reason we do this now instead of passing the alias to the
3096 # search_rs below is that if you wrap/overload resultset on the
3097 # source you need to know what alias it's -going- to have for things
3098 # to work sanely (e.g. RestrictWithObject wants to be able to add
3099 # extra query restrictions, and these may need to be $alias.)
3101 my $rel_attrs = $rel_source->resultset_attributes;
3102 local $rel_attrs->{alias} = $alias;
3104 $rel_source->resultset
3108 where => $attrs->{where},
3111 $new->set_cache($related_cache) if $related_cache;
3116 =head2 current_source_alias
3120 =item Arguments: none
3122 =item Return Value: $source_alias
3126 Returns the current table alias for the result source this resultset is built
3127 on, that will be used in the SQL query. Usually it is C<me>.
3129 Currently the source alias that refers to the result set returned by a
3130 L</search>/L</find> family method depends on how you got to the resultset: it's
3131 C<me> by default, but eg. L</search_related> aliases it to the related result
3132 source name (and keeps C<me> referring to the original result set). The long
3133 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3134 (and make this method unnecessary).
3136 Thus it's currently necessary to use this method in predefined queries (see
3137 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3138 source alias of the current result set:
3140 # in a result set class
3142 my ($self, $user) = @_;
3144 my $me = $self->current_source_alias;
3146 return $self->search({
3147 "$me.modified" => $user->id,
3153 sub current_source_alias {
3154 return (shift->{attrs} || {})->{alias} || 'me';
3157 =head2 as_subselect_rs
3161 =item Arguments: none
3163 =item Return Value: L<$resultset|/search>
3167 Act as a barrier to SQL symbols. The resultset provided will be made into a
3168 "virtual view" by including it as a subquery within the from clause. From this
3169 point on, any joined tables are inaccessible to ->search on the resultset (as if
3170 it were simply where-filtered without joins). For example:
3172 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3174 # 'x' now pollutes the query namespace
3176 # So the following works as expected
3177 my $ok_rs = $rs->search({'x.other' => 1});
3179 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3180 # def) we look for one row with contradictory terms and join in another table
3181 # (aliased 'x_2') which we never use
3182 my $broken_rs = $rs->search({'x.name' => 'def'});
3184 my $rs2 = $rs->as_subselect_rs;
3186 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3187 my $not_joined_rs = $rs2->search({'x.other' => 1});
3189 # works as expected: finds a 'table' row related to two x rows (abc and def)
3190 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3192 Another example of when one might use this would be to select a subset of
3193 columns in a group by clause:
3195 my $rs = $schema->resultset('Bar')->search(undef, {
3196 group_by => [qw{ id foo_id baz_id }],
3197 })->as_subselect_rs->search(undef, {
3198 columns => [qw{ id foo_id }]
3201 In the above example normally columns would have to be equal to the group by,
3202 but because we isolated the group by into a subselect the above works.
3206 sub as_subselect_rs {
3209 my $attrs = $self->_resolved_attrs;
3211 my $fresh_rs = (ref $self)->new (
3212 $self->result_source
3215 # these pieces will be locked in the subquery
3216 delete $fresh_rs->{cond};
3217 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3219 return $fresh_rs->search( {}, {
3221 $attrs->{alias} => $self->as_query,
3222 -alias => $attrs->{alias},
3223 -rsrc => $self->result_source,
3225 alias => $attrs->{alias},
3229 # This code is called by search_related, and makes sure there
3230 # is clear separation between the joins before, during, and
3231 # after the relationship. This information is needed later
3232 # in order to properly resolve prefetch aliases (any alias
3233 # with a relation_chain_depth less than the depth of the
3234 # current prefetch is not considered)
3236 # The increments happen twice per join. An even number means a
3237 # relationship specified via a search_related, whereas an odd
3238 # number indicates a join/prefetch added via attributes
3240 # Also this code will wrap the current resultset (the one we
3241 # chain to) in a subselect IFF it contains limiting attributes
3242 sub _chain_relationship {
3243 my ($self, $rel) = @_;
3244 my $source = $self->result_source;
3245 my $attrs = { %{$self->{attrs}||{}} };
3247 # we need to take the prefetch the attrs into account before we
3248 # ->_resolve_join as otherwise they get lost - captainL
3249 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3251 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
3253 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3256 my @force_subq_attrs = qw/offset rows group_by having/;
3259 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3261 $self->_has_resolved_attr (@force_subq_attrs)
3263 # Nuke the prefetch (if any) before the new $rs attrs
3264 # are resolved (prefetch is useless - we are wrapping
3265 # a subquery anyway).
3266 my $rs_copy = $self->search;
3267 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3268 $rs_copy->{attrs}{join},
3269 delete $rs_copy->{attrs}{prefetch},
3274 -alias => $attrs->{alias},
3275 $attrs->{alias} => $rs_copy->as_query,
3277 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3278 $seen->{-relation_chain_depth} = 0;
3280 elsif ($attrs->{from}) { #shallow copy suffices
3281 $from = [ @{$attrs->{from}} ];
3286 -alias => $attrs->{alias},
3287 $attrs->{alias} => $source->from,
3291 my $jpath = ($seen->{-relation_chain_depth})
3292 ? $from->[-1][0]{-join_path}
3295 my @requested_joins = $source->_resolve_join(
3302 push @$from, @requested_joins;
3304 $seen->{-relation_chain_depth}++;
3306 # if $self already had a join/prefetch specified on it, the requested
3307 # $rel might very well be already included. What we do in this case
3308 # is effectively a no-op (except that we bump up the chain_depth on
3309 # the join in question so we could tell it *is* the search_related)
3312 # we consider the last one thus reverse
3313 for my $j (reverse @requested_joins) {
3314 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3315 if ($rel eq $last_j) {
3316 $j->[0]{-relation_chain_depth}++;
3322 unless ($already_joined) {
3323 push @$from, $source->_resolve_join(
3331 $seen->{-relation_chain_depth}++;
3333 return {%$attrs, from => $from, seen_join => $seen};
3336 # FIXME - this needs to go live in Schema with the tree walker... or
3338 my $inflatemap_checker;
3339 $inflatemap_checker = sub {
3340 my ($rsrc, $relpaths) = @_;
3345 $_ =~ /^ ( [^\.]+ ) \. (.+) $/x
3348 push @{$rels->{$1}}, $2;
3351 for my $rel (keys %$rels) {
3352 my $rel_rsrc = try {
3353 $rsrc->related_source ($rel)
3355 $rsrc->throw_exception(sprintf(
3356 "Inflation into non-existent relationship '%s' of '%s' requested, "
3357 . "check the inflation specification (columns/as) ending in '...%s.%s'",
3361 ( sort { length($a) <=> length ($b) } @{$rels->{$rel}} )[0],
3364 $inflatemap_checker->($rel_rsrc, $rels->{$rel});
3370 sub _resolved_attrs {
3372 return $self->{_attrs} if $self->{_attrs};
3374 my $attrs = { %{ $self->{attrs} || {} } };
3375 my $source = $self->result_source;
3376 my $alias = $attrs->{alias};
3378 # default selection list
3379 $attrs->{columns} = [ $source->columns ]
3380 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3382 # merge selectors together
3383 for (qw/columns select as/) {
3384 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3385 if $attrs->{$_} or $attrs->{"+$_"};
3388 # disassemble columns
3390 if (my $cols = delete $attrs->{columns}) {
3391 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3392 if (ref $c eq 'HASH') {
3393 for my $as (sort keys %$c) {
3394 push @sel, $c->{$as};
3405 # when trying to weed off duplicates later do not go past this point -
3406 # everything added from here on is unbalanced "anyone's guess" stuff
3407 my $dedup_stop_idx = $#as;
3409 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3411 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3412 if $attrs->{select};
3414 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3415 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3417 # disqualify all $alias.col as-bits (inflate-map mandated)
3418 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3420 # de-duplicate the result (remove *identical* select/as pairs)
3421 # and also die on duplicate {as} pointing to different {select}s
3422 # not using a c-style for as the condition is prone to shrinkage
3425 while ($i <= $dedup_stop_idx) {
3426 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3431 elsif ($seen->{$as[$i]}++) {
3432 $self->throw_exception(
3433 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3441 # validate the user-supplied 'as' chain
3442 # folks get too confused by the (logical) exception message, need to
3443 # go to some lengths to clarify the text
3445 # FIXME - this needs to go live in Schema with the tree walker... or
3447 $inflatemap_checker->($source, \@as);
3449 $attrs->{select} = \@sel;
3450 $attrs->{as} = \@as;
3452 $attrs->{from} ||= [{
3454 -alias => $self->{attrs}{alias},
3455 $self->{attrs}{alias} => $source->from,
3458 if ( $attrs->{join} || $attrs->{prefetch} ) {
3460 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3461 if ref $attrs->{from} ne 'ARRAY';
3463 my $join = (delete $attrs->{join}) || {};
3465 if ( defined $attrs->{prefetch} ) {
3466 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3469 $attrs->{from} = # have to copy here to avoid corrupting the original
3471 @{ $attrs->{from} },
3472 $source->_resolve_join(
3475 { %{ $attrs->{seen_join} || {} } },
3476 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3477 ? $attrs->{from}[-1][0]{-join_path}
3484 if ( defined $attrs->{order_by} ) {
3485 $attrs->{order_by} = (
3486 ref( $attrs->{order_by} ) eq 'ARRAY'
3487 ? [ @{ $attrs->{order_by} } ]
3488 : [ $attrs->{order_by} || () ]
3492 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3493 $attrs->{group_by} = [ $attrs->{group_by} ];
3496 # generate the distinct induced group_by early, as prefetch will be carried via a
3497 # subquery (since a group_by is present)
3498 if (delete $attrs->{distinct}) {
3499 if ($attrs->{group_by}) {
3500 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3503 # distinct affects only the main selection part, not what prefetch may
3505 $attrs->{group_by} = $source->storage->_group_over_selection (
3513 # generate selections based on the prefetch helper
3515 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3516 if defined $attrs->{prefetch};
3520 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3521 if $attrs->{_dark_selector};
3523 $attrs->{collapse} = 1;
3525 # this is a separate structure (we don't look in {from} directly)
3526 # as the resolver needs to shift things off the lists to work
3527 # properly (identical-prefetches on different branches)
3529 if (ref $attrs->{from} eq 'ARRAY') {
3531 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3533 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3534 next unless $j->[0]{-alias};
3535 next unless $j->[0]{-join_path};
3536 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3538 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3541 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3542 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3546 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3548 # we need to somehow mark which columns came from prefetch
3550 my $sel_end = $#{$attrs->{select}};
3551 $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
3554 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3555 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3558 if ( ! List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3559 $attrs->{_single_resultclass_inflation} = 1;
3560 $attrs->{collapse} = 0;
3563 # run through the resulting joinstructure (starting from our current slot)
3564 # and unset collapse if proven unnesessary
3566 # also while we are at it find out if the current root source has
3567 # been premultiplied by previous related_source chaining
3569 # this allows to predict whether a root object with all other relation
3570 # data set to NULL is in fact unique
3571 if ($attrs->{collapse}) {
3573 if (ref $attrs->{from} eq 'ARRAY') {
3575 if (@{$attrs->{from}} <= 1) {
3576 # no joins - no collapse
3577 $attrs->{collapse} = 0;
3580 # find where our table-spec starts
3581 my @fromlist = @{$attrs->{from}};
3583 my $t = shift @fromlist;
3586 # me vs join from-spec distinction - a ref means non-root
3587 if (ref $t eq 'ARRAY') {
3589 $is_multi ||= ! $t->{-is_single};
3591 last if ($t->{-alias} && $t->{-alias} eq $alias);
3592 $attrs->{_main_source_premultiplied} ||= $is_multi;
3595 # no non-singles remaining, nor any premultiplication - nothing to collapse
3597 ! $attrs->{_main_source_premultiplied}
3599 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3601 $attrs->{collapse} = 0;
3607 # if we can not analyze the from - err on the side of safety
3608 $attrs->{_main_source_premultiplied} = 1;
3612 # if both page and offset are specified, produce a combined offset
3613 # even though it doesn't make much sense, this is what pre 081xx has
3615 if (my $page = delete $attrs->{page}) {
3617 ($attrs->{rows} * ($page - 1))
3619 ($attrs->{offset} || 0)
3623 return $self->{_attrs} = $attrs;
3627 my ($self, $attr) = @_;
3629 if (ref $attr eq 'HASH') {
3630 return $self->_rollout_hash($attr);
3631 } elsif (ref $attr eq 'ARRAY') {
3632 return $self->_rollout_array($attr);
3638 sub _rollout_array {
3639 my ($self, $attr) = @_;
3642 foreach my $element (@{$attr}) {
3643 if (ref $element eq 'HASH') {
3644 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3645 } elsif (ref $element eq 'ARRAY') {
3646 # XXX - should probably recurse here
3647 push( @rolled_array, @{$self->_rollout_array($element)} );
3649 push( @rolled_array, $element );
3652 return \@rolled_array;
3656 my ($self, $attr) = @_;
3659 foreach my $key (keys %{$attr}) {
3660 push( @rolled_array, { $key => $attr->{$key} } );
3662 return \@rolled_array;
3665 sub _calculate_score {
3666 my ($self, $a, $b) = @_;
3668 if (defined $a xor defined $b) {
3671 elsif (not defined $a) {
3675 if (ref $b eq 'HASH') {
3676 my ($b_key) = keys %{$b};
3677 if (ref $a eq 'HASH') {
3678 my ($a_key) = keys %{$a};
3679 if ($a_key eq $b_key) {
3680 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3685 return ($a eq $b_key) ? 1 : 0;
3688 if (ref $a eq 'HASH') {
3689 my ($a_key) = keys %{$a};
3690 return ($b eq $a_key) ? 1 : 0;
3692 return ($b eq $a) ? 1 : 0;
3697 sub _merge_joinpref_attr {
3698 my ($self, $orig, $import) = @_;
3700 return $import unless defined($orig);
3701 return $orig unless defined($import);
3703 $orig = $self->_rollout_attr($orig);
3704 $import = $self->_rollout_attr($import);
3707 foreach my $import_element ( @{$import} ) {
3708 # find best candidate from $orig to merge $b_element into
3709 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3710 foreach my $orig_element ( @{$orig} ) {
3711 my $score = $self->_calculate_score( $orig_element, $import_element );
3712 if ($score > $best_candidate->{score}) {
3713 $best_candidate->{position} = $position;
3714 $best_candidate->{score} = $score;
3718 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3719 $import_key = '' if not defined $import_key;
3721 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3722 push( @{$orig}, $import_element );
3724 my $orig_best = $orig->[$best_candidate->{position}];
3725 # merge orig_best and b_element together and replace original with merged
3726 if (ref $orig_best ne 'HASH') {
3727 $orig->[$best_candidate->{position}] = $import_element;
3728 } elsif (ref $import_element eq 'HASH') {
3729 my ($key) = keys %{$orig_best};
3730 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3733 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3736 return @$orig ? $orig : ();
3744 require Hash::Merge;
3745 my $hm = Hash::Merge->new;
3747 $hm->specify_behavior({
3750 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3752 if ($defl xor $defr) {
3753 return [ $defl ? $_[0] : $_[1] ];
3758 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3762 return [$_[0], $_[1]];
3766 return $_[1] if !defined $_[0];
3767 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3768 return [$_[0], @{$_[1]}]
3771 return [] if !defined $_[0] and !keys %{$_[1]};
3772 return [ $_[1] ] if !defined $_[0];
3773 return [ $_[0] ] if !keys %{$_[1]};
3774 return [$_[0], $_[1]]
3779 return $_[0] if !defined $_[1];
3780 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3781 return [@{$_[0]}, $_[1]]
3784 my @ret = @{$_[0]} or return $_[1];
3785 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3786 my %idx = map { $_ => 1 } @ret;
3787 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3791 return [ $_[1] ] if ! @{$_[0]};
3792 return $_[0] if !keys %{$_[1]};
3793 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3794 return [ @{$_[0]}, $_[1] ];
3799 return [] if !keys %{$_[0]} and !defined $_[1];
3800 return [ $_[0] ] if !defined $_[1];
3801 return [ $_[1] ] if !keys %{$_[0]};
3802 return [$_[0], $_[1]]
3805 return [] if !keys %{$_[0]} and !@{$_[1]};
3806 return [ $_[0] ] if !@{$_[1]};
3807 return $_[1] if !keys %{$_[0]};
3808 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3809 return [ $_[0], @{$_[1]} ];
3812 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3813 return [ $_[0] ] if !keys %{$_[1]};
3814 return [ $_[1] ] if !keys %{$_[0]};
3815 return [ $_[0] ] if $_[0] eq $_[1];
3816 return [ $_[0], $_[1] ];
3819 } => 'DBIC_RS_ATTR_MERGER');
3823 return $hm->merge ($_[1], $_[2]);
3827 sub STORABLE_freeze {
3828 my ($self, $cloning) = @_;
3829 my $to_serialize = { %$self };
3831 # A cursor in progress can't be serialized (and would make little sense anyway)
3832 # the parser can be regenerated (and can't be serialized)
3833 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3835 # nor is it sensical to store a not-yet-fired-count pager
3836 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3837 delete $to_serialize->{pager};
3840 Storable::nfreeze($to_serialize);
3843 # need this hook for symmetry
3845 my ($self, $cloning, $serialized) = @_;
3847 %$self = %{ Storable::thaw($serialized) };
3853 =head2 throw_exception
3855 See L<DBIx::Class::Schema/throw_exception> for details.
3859 sub throw_exception {
3862 if (ref $self and my $rsrc = $self->result_source) {
3863 $rsrc->throw_exception(@_)
3866 DBIx::Class::Exception->throw(@_);
3874 # XXX: FIXME: Attributes docs need clearing up
3878 Attributes are used to refine a ResultSet in various ways when
3879 searching for data. They can be passed to any method which takes an
3880 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3883 Default attributes can be set on the result class using
3884 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3885 the CAVEATS on that feature before using it!)
3887 These are in no particular order:
3893 =item Value: ( $order_by | \@order_by | \%order_by )
3897 Which column(s) to order the results by.
3899 [The full list of suitable values is documented in
3900 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3903 If a single column name, or an arrayref of names is supplied, the
3904 argument is passed through directly to SQL. The hashref syntax allows
3905 for connection-agnostic specification of ordering direction:
3907 For descending order:
3909 order_by => { -desc => [qw/col1 col2 col3/] }
3911 For explicit ascending order:
3913 order_by => { -asc => 'col' }
3915 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3916 supported, although you are strongly encouraged to use the hashref
3917 syntax as outlined above.
3923 =item Value: \@columns | \%columns | $column
3927 Shortcut to request a particular set of columns to be retrieved. Each
3928 column spec may be a string (a table column name), or a hash (in which
3929 case the key is the C<as> value, and the value is used as the C<select>
3930 expression). Adds C<me.> onto the start of any column without a C<.> in
3931 it and sets C<select> from that, then auto-populates C<as> from
3932 C<select> as normal. (You may also use the C<cols> attribute, as in
3933 earlier versions of DBIC.)
3935 Essentially C<columns> does the same as L</select> and L</as>.
3937 columns => [ 'foo', { bar => 'baz' } ]
3941 select => [qw/foo baz/],
3948 =item Value: \@columns
3952 Indicates additional columns to be selected from storage. Works the same
3953 as L</columns> but adds columns to the selection. (You may also use the
3954 C<include_columns> attribute, as in earlier versions of DBIC). For
3957 $schema->resultset('CD')->search(undef, {
3958 '+columns' => ['artist.name'],
3962 would return all CDs and include a 'name' column to the information
3963 passed to object inflation. Note that the 'artist' is the name of the
3964 column (or relationship) accessor, and 'name' is the name of the column
3965 accessor in the related table.
3967 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3968 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3969 unary plus operator before it.
3971 =head2 include_columns
3975 =item Value: \@columns
3979 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3985 =item Value: \@select_columns
3989 Indicates which columns should be selected from the storage. You can use
3990 column names, or in the case of RDBMS back ends, function or stored procedure
3993 $rs = $schema->resultset('Employee')->search(undef, {
3996 { count => 'employeeid' },
3997 { max => { length => 'name' }, -as => 'longest_name' }
4002 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
4004 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
4005 use L</select>, to instruct DBIx::Class how to store the result of the column.
4006 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
4007 identifier aliasing. You can however alias a function, so you can use it in
4008 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
4009 attribute> supplied as shown in the example above.
4011 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
4012 Not doing so causes Perl to incorrectly interpret them as a bareword with a
4013 unary plus operator before it.
4019 Indicates additional columns to be selected from storage. Works the same as
4020 L</select> but adds columns to the default selection, instead of specifying
4029 =item Value: \@inflation_names
4033 Indicates column names for object inflation. That is L</as> indicates the
4034 slot name in which the column value will be stored within the
4035 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4036 identifier by the C<get_column> method (or via the object accessor B<if one
4037 with the same name already exists>) as shown below. The L</as> attribute has
4038 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4040 $rs = $schema->resultset('Employee')->search(undef, {
4043 { count => 'employeeid' },
4044 { max => { length => 'name' }, -as => 'longest_name' }
4053 If the object against which the search is performed already has an accessor
4054 matching a column name specified in C<as>, the value can be retrieved using
4055 the accessor as normal:
4057 my $name = $employee->name();
4059 If on the other hand an accessor does not exist in the object, you need to
4060 use C<get_column> instead:
4062 my $employee_count = $employee->get_column('employee_count');
4064 You can create your own accessors if required - see
4065 L<DBIx::Class::Manual::Cookbook> for details.
4071 Indicates additional column names for those added via L</+select>. See L</as>.
4079 =item Value: ($rel_name | \@rel_names | \%rel_names)
4083 Contains a list of relationships that should be joined for this query. For
4086 # Get CDs by Nine Inch Nails
4087 my $rs = $schema->resultset('CD')->search(
4088 { 'artist.name' => 'Nine Inch Nails' },
4089 { join => 'artist' }
4092 Can also contain a hash reference to refer to the other relation's relations.
4095 package MyApp::Schema::Track;
4096 use base qw/DBIx::Class/;
4097 __PACKAGE__->table('track');
4098 __PACKAGE__->add_columns(qw/trackid cd position title/);
4099 __PACKAGE__->set_primary_key('trackid');
4100 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4103 # In your application
4104 my $rs = $schema->resultset('Artist')->search(
4105 { 'track.title' => 'Teardrop' },
4107 join => { cd => 'track' },
4108 order_by => 'artist.name',
4112 You need to use the relationship (not the table) name in conditions,
4113 because they are aliased as such. The current table is aliased as "me", so
4114 you need to use me.column_name in order to avoid ambiguity. For example:
4116 # Get CDs from 1984 with a 'Foo' track
4117 my $rs = $schema->resultset('CD')->search(
4120 'tracks.name' => 'Foo'
4122 { join => 'tracks' }
4125 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4126 similarly for a third time). For e.g.
4128 my $rs = $schema->resultset('Artist')->search({
4129 'cds.title' => 'Down to Earth',
4130 'cds_2.title' => 'Popular',
4132 join => [ qw/cds cds/ ],
4135 will return a set of all artists that have both a cd with title 'Down
4136 to Earth' and a cd with title 'Popular'.
4138 If you want to fetch related objects from other tables as well, see L</prefetch>
4141 NOTE: An internal join-chain pruner will discard certain joins while
4142 constructing the actual SQL query, as long as the joins in question do not
4143 affect the retrieved result. This for example includes 1:1 left joins
4144 that are not part of the restriction specification (WHERE/HAVING) nor are
4145 a part of the query selection.
4147 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4153 =item Value: (0 | 1)
4157 When set to a true value, indicates that any rows fetched from joined has_many
4158 relationships are to be aggregated into the corresponding "parent" object. For
4159 example, the resultset:
4161 my $rs = $schema->resultset('CD')->search({}, {
4162 '+columns' => [ qw/ tracks.title tracks.position / ],
4167 While executing the following query:
4169 SELECT me.*, tracks.title, tracks.position
4171 LEFT JOIN track tracks
4172 ON tracks.cdid = me.cdid
4174 Will return only as many objects as there are rows in the CD source, even
4175 though the result of the query may span many rows. Each of these CD objects
4176 will in turn have multiple "Track" objects hidden behind the has_many
4177 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4178 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4179 product"), with each CD object containing exactly one of all fetched Track data.
4181 When a collapse is requested on a non-ordered resultset, an order by some
4182 unique part of the main source (the left-most table) is inserted automatically.
4183 This is done so that the resultset is allowed to be "lazy" - calling
4184 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4185 object with all of its related data.
4187 If an L</order_by> is already declared, and orders the resultset in a way that
4188 makes collapsing as described above impossible (e.g. C<< ORDER BY
4189 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4190 switch to "eager" mode and slurp the entire resultset before consturcting the
4191 first object returned by L</next>.
4193 Setting this attribute on a resultset that does not join any has_many
4194 relations is a no-op.
4196 For a more in-depth discussion, see L</PREFETCHING>.
4202 =item Value: ($rel_name | \@rel_names | \%rel_names)
4206 This attribute is a shorthand for specifying a L</join> spec, adding all
4207 columns from the joined related sources as L</+columns> and setting
4208 L</collapse> to a true value. For example, the following two queries are
4211 my $rs = $schema->resultset('Artist')->search({}, {
4212 prefetch => { cds => ['genre', 'tracks' ] },
4217 my $rs = $schema->resultset('Artist')->search({}, {
4218 join => { cds => ['genre', 'tracks' ] },
4222 { +{ "cds.$_" => "cds.$_" } }
4223 $schema->source('Artist')->related_source('cds')->columns
4226 { +{ "cds.genre.$_" => "genre.$_" } }
4227 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4230 { +{ "cds.tracks.$_" => "tracks.$_" } }
4231 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4236 Both producing the following SQL:
4238 SELECT me.artistid, me.name, me.rank, me.charfield,
4239 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4240 genre.genreid, genre.name,
4241 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4244 ON cds.artist = me.artistid
4245 LEFT JOIN genre genre
4246 ON genre.genreid = cds.genreid
4247 LEFT JOIN track tracks
4248 ON tracks.cd = cds.cdid
4249 ORDER BY me.artistid
4251 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4252 the arguments are properly merged and generally do the right thing. For
4253 example, you may want to do the following:
4255 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4256 { 'genre.genreid' => undef },
4258 join => { cds => 'genre' },
4263 Which generates the following SQL:
4265 SELECT me.artistid, me.name, me.rank, me.charfield,
4266 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4269 ON cds.artist = me.artistid
4270 LEFT JOIN genre genre
4271 ON genre.genreid = cds.genreid
4272 WHERE genre.genreid IS NULL
4273 ORDER BY me.artistid
4275 For a more in-depth discussion, see L</PREFETCHING>.
4281 =item Value: $source_alias
4285 Sets the source alias for the query. Normally, this defaults to C<me>, but
4286 nested search queries (sub-SELECTs) might need specific aliases set to
4287 reference inner queries. For example:
4290 ->related_resultset('CDs')
4291 ->related_resultset('Tracks')
4293 'track.id' => { -ident => 'none_search.id' },
4297 my $ids = $self->search({
4300 alias => 'none_search',
4301 group_by => 'none_search.id',
4302 })->get_column('id')->as_query;
4304 $self->search({ id => { -in => $ids } })
4306 This attribute is directly tied to L</current_source_alias>.
4316 Makes the resultset paged and specifies the page to retrieve. Effectively
4317 identical to creating a non-pages resultset and then calling ->page($page)
4320 If L</rows> attribute is not specified it defaults to 10 rows per page.
4322 When you have a paged resultset, L</count> will only return the number
4323 of rows in the page. To get the total, use the L</pager> and call
4324 C<total_entries> on it.
4334 Specifies the maximum number of rows for direct retrieval or the number of
4335 rows per page if the page attribute or method is used.
4341 =item Value: $offset
4345 Specifies the (zero-based) row number for the first row to be returned, or the
4346 of the first row of the first page if paging is used.
4348 =head2 software_limit
4352 =item Value: (0 | 1)
4356 When combined with L</rows> and/or L</offset> the generated SQL will not
4357 include any limit dialect stanzas. Instead the entire result will be selected
4358 as if no limits were specified, and DBIC will perform the limit locally, by
4359 artificially advancing and finishing the resulting L</cursor>.
4361 This is the recommended way of performing resultset limiting when no sane RDBMS
4362 implementation is available (e.g.
4363 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4364 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4370 =item Value: \@columns
4374 A arrayref of columns to group by. Can include columns of joined tables.
4376 group_by => [qw/ column1 column2 ... /]
4382 =item Value: $condition
4386 HAVING is a select statement attribute that is applied between GROUP BY and
4387 ORDER BY. It is applied to the after the grouping calculations have been
4390 having => { 'count_employee' => { '>=', 100 } }
4392 or with an in-place function in which case literal SQL is required:
4394 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4400 =item Value: (0 | 1)
4404 Set to 1 to group by all columns. If the resultset already has a group_by
4405 attribute, this setting is ignored and an appropriate warning is issued.
4411 Adds to the WHERE clause.
4413 # only return rows WHERE deleted IS NULL for all searches
4414 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4416 Can be overridden by passing C<< { where => undef } >> as an attribute
4419 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4425 Set to 1 to cache search results. This prevents extra SQL queries if you
4426 revisit rows in your ResultSet:
4428 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4430 while( my $artist = $resultset->next ) {
4434 $rs->first; # without cache, this would issue a query
4436 By default, searches are not cached.
4438 For more examples of using these attributes, see
4439 L<DBIx::Class::Manual::Cookbook>.
4445 =item Value: ( 'update' | 'shared' | \$scalar )
4449 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4450 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4455 DBIx::Class supports arbitrary related data prefetching from multiple related
4456 sources. Any combination of relationship types and column sets are supported.
4457 If L<collapsing|/collapse> is requested, there is an additional requirement of
4458 selecting enough data to make every individual object uniquely identifiable.
4460 Here are some more involved examples, based on the following relationship map:
4463 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4464 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4465 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4467 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4469 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4473 my $rs = $schema->resultset('Tag')->search(
4482 The initial search results in SQL like the following:
4484 SELECT tag.*, cd.*, artist.* FROM tag
4485 JOIN cd ON tag.cd = cd.cdid
4486 JOIN artist ON cd.artist = artist.artistid
4488 L<DBIx::Class> has no need to go back to the database when we access the
4489 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4492 Simple prefetches will be joined automatically, so there is no need
4493 for a C<join> attribute in the above search.
4495 The L</prefetch> attribute can be used with any of the relationship types
4496 and multiple prefetches can be specified together. Below is a more complex
4497 example that prefetches a CD's artist, its liner notes (if present),
4498 the cover image, the tracks on that CD, and the guests on those
4501 my $rs = $schema->resultset('CD')->search(
4505 { artist => 'record_label'}, # belongs_to => belongs_to
4506 'liner_note', # might_have
4507 'cover_image', # has_one
4508 { tracks => 'guests' }, # has_many => has_many
4513 This will produce SQL like the following:
4515 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4519 ON artist.artistid = me.artistid
4520 JOIN record_label record_label
4521 ON record_label.labelid = artist.labelid
4522 LEFT JOIN track tracks
4523 ON tracks.cdid = me.cdid
4524 LEFT JOIN guest guests
4525 ON guests.trackid = track.trackid
4526 LEFT JOIN liner_notes liner_note
4527 ON liner_note.cdid = me.cdid
4528 JOIN cd_artwork cover_image
4529 ON cover_image.cdid = me.cdid
4532 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4533 C<tracks>, and C<guests> of the CD will all be available through the
4534 relationship accessors without the need for additional queries to the
4539 Prefetch does a lot of deep magic. As such, it may not behave exactly
4540 as you might expect.
4546 Prefetch uses the L</cache> to populate the prefetched relationships. This
4547 may or may not be what you want.
4551 If you specify a condition on a prefetched relationship, ONLY those
4552 rows that match the prefetched condition will be fetched into that relationship.
4553 This means that adding prefetch to a search() B<may alter> what is returned by
4554 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4556 my $artist_rs = $schema->resultset('Artist')->search({
4562 my $count = $artist_rs->first->cds->count;
4564 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4566 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4568 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4570 That cmp_ok() may or may not pass depending on the datasets involved. In other
4571 words the C<WHERE> condition would apply to the entire dataset, just like
4572 it would in regular SQL. If you want to add a condition only to the "right side"
4573 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4574 condition|DBIx::Class::Relationship::Base/condition>
4578 =head1 DBIC BIND VALUES
4580 Because DBIC may need more information to bind values than just the column name
4581 and value itself, it uses a special format for both passing and receiving bind
4582 values. Each bind value should be composed of an arrayref of
4583 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4589 If present (in any form), this is what is being passed directly to bind_param.
4590 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4591 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4593 If this is specified, all other bind options described below are ignored.
4597 If present, this is used to infer the actual bind attribute by passing to
4598 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4599 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4601 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4602 currently drivers are expected to "Do the Right Thing" when given a common
4603 datatype name. (Not ideal, but that's what we got at this point.)
4607 Currently used to correctly allocate buffers for bind_param_inout().
4608 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4609 or to a sensible value based on the "data_type".
4613 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4614 explicitly specified they are never overriden). Also used by some weird DBDs,
4615 where the column name should be available at bind_param time (e.g. Oracle).
4619 For backwards compatibility and convenience, the following shortcuts are
4622 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4623 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4624 [ undef, $val ] === [ {}, $val ]
4626 =head1 AUTHOR AND CONTRIBUTORS
4628 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4632 You may distribute this code under the same terms as Perl itself.