1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::ResultSetColumn;
8 use Scalar::Util qw/blessed weaken reftype/;
10 use Data::Compare (); # no imports!!! guard against insane architecture
12 # not importing first() as it will clash with our own method
16 # De-duplication in _merge_attr() is disabled, but left in for reference
17 # (the merger is used for other things that ought not to be de-duped)
18 *__HM_DEDUP = sub () { 0 };
28 # this is real - CDBICompat overrides it with insanity
29 # yes, prototype won't matter, but that's for now ;)
32 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
36 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
40 my $users_rs = $schema->resultset('User');
41 while( $user = $users_rs->next) {
42 print $user->username;
45 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
46 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
50 A ResultSet is an object which stores a set of conditions representing
51 a query. It is the backbone of DBIx::Class (i.e. the really
52 important/useful bit).
54 No SQL is executed on the database when a ResultSet is created, it
55 just stores all the conditions needed to create the query.
57 A basic ResultSet representing the data of an entire table is returned
58 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
59 L<Source|DBIx::Class::Manual::Glossary/Source> name.
61 my $users_rs = $schema->resultset('User');
63 A new ResultSet is returned from calling L</search> on an existing
64 ResultSet. The new one will contain all the conditions of the
65 original, plus any new conditions added in the C<search> call.
67 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
68 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
71 The query that the ResultSet represents is B<only> executed against
72 the database when these methods are called:
73 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
75 If a resultset is used in a numeric context it returns the L</count>.
76 However, if it is used in a boolean context it is B<always> true. So if
77 you want to check if a resultset has any results, you must use C<if $rs
80 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
82 If you want to make your custom ResultSet classes with L<Moose>, use a template
85 package MyApp::Schema::ResultSet::User;
88 use namespace::autoclean;
90 extends 'DBIx::Class::ResultSet';
92 sub BUILDARGS { $_[2] }
96 __PACKAGE__->meta->make_immutable;
100 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
101 clash with the regular ResultSet constructor. Alternatively, you can use:
103 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
105 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
106 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
110 =head2 Chaining resultsets
112 Let's say you've got a query that needs to be run to return some data
113 to the user. But, you have an authorization system in place that
114 prevents certain users from seeing certain information. So, you want
115 to construct the basic query in one method, but add constraints to it in
120 my $request = $self->get_request; # Get a request object somehow.
121 my $schema = $self->result_source->schema;
123 my $cd_rs = $schema->resultset('CD')->search({
124 title => $request->param('title'),
125 year => $request->param('year'),
128 $cd_rs = $self->apply_security_policy( $cd_rs );
130 return $cd_rs->all();
133 sub apply_security_policy {
142 =head3 Resolving conditions and attributes
144 When a resultset is chained from another resultset (ie:
145 C<my $new_rs = $old_rs->search(\%extra_cond, \%attrs)>), conditions
146 and attributes with the same keys need resolving.
148 If any of L</columns>, L</select>, L</as> are present, they reset the
149 original selection, and start the selection "clean".
151 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
152 are merged into the existing ones from the original resultset.
154 The L</where> and L</having> attributes, and any search conditions, are
155 merged with an SQL C<AND> to the existing condition from the original
158 All other attributes are overridden by any new ones supplied in the
161 =head2 Multiple queries
163 Since a resultset just defines a query, you can do all sorts of
164 things with it with the same object.
166 # Don't hit the DB yet.
167 my $cd_rs = $schema->resultset('CD')->search({
168 title => 'something',
172 # Each of these hits the DB individually.
173 my $count = $cd_rs->count;
174 my $most_recent = $cd_rs->get_column('date_released')->max();
175 my @records = $cd_rs->all;
177 And it's not just limited to SELECT statements.
183 $cd_rs->create({ artist => 'Fred' });
185 Which is the same as:
187 $schema->resultset('CD')->create({
188 title => 'something',
193 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
201 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
203 =item Return Value: L<$resultset|/search>
207 The resultset constructor. Takes a source object (usually a
208 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
209 L</ATTRIBUTES> below). Does not perform any queries -- these are
210 executed as needed by the other methods.
212 Generally you never construct a resultset manually. Instead you get one
214 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
215 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
218 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
224 If called on an object, proxies to L</new_result> instead, so
226 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
228 will return a CD object, not a ResultSet, and is equivalent to:
230 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
232 Please also keep in mind that many internals call L</new_result> directly,
233 so overloading this method with the idea of intercepting new result object
234 creation B<will not work>. See also warning pertaining to L</create>.
242 return $class->new_result(@_) if ref $class;
244 my ($source, $attrs) = @_;
245 $source = $source->resolve
246 if $source->isa('DBIx::Class::ResultSourceHandle');
247 $attrs = { %{$attrs||{}} };
249 if ($attrs->{page}) {
250 $attrs->{rows} ||= 10;
253 $attrs->{alias} ||= 'me';
256 result_source => $source,
257 cond => $attrs->{where},
262 # if there is a dark selector, this means we are already in a
263 # chain and the cleanup/sanification was taken care of by
265 $self->_normalize_selection($attrs)
266 unless $attrs->{_dark_selector};
269 $attrs->{result_class} || $source->result_class
279 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
281 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
285 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
286 my $new_rs = $cd_rs->search({ year => 2005 });
288 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
289 # year = 2005 OR year = 2004
291 In list context, C<< ->all() >> is called implicitly on the resultset, thus
292 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
293 To avoid that, use L</search_rs>.
295 If you need to pass in additional attributes but no additional condition,
296 call it as C<search(undef, \%attrs)>.
298 # "SELECT name, artistid FROM $artist_table"
299 my @all_artists = $schema->resultset('Artist')->search(undef, {
300 columns => [qw/name artistid/],
303 For a list of attributes that can be passed to C<search>, see
304 L</ATTRIBUTES>. For more examples of using this function, see
305 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
306 documentation for the first argument, see L<SQL::Abstract>
307 and its extension L<DBIx::Class::SQLMaker>.
309 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
313 Note that L</search> does not process/deflate any of the values passed in the
314 L<SQL::Abstract>-compatible search condition structure. This is unlike other
315 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
316 manually that any value passed to this method will stringify to something the
317 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
318 objects, for more info see:
319 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
325 my $rs = $self->search_rs( @_ );
330 elsif (defined wantarray) {
334 # we can be called by a relationship helper, which in
335 # turn may be called in void context due to some braindead
336 # overload or whatever else the user decided to be clever
337 # at this particular day. Thus limit the exception to
338 # external code calls only
339 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
340 if (caller)[0] !~ /^\QDBIx::Class::/;
350 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
352 =item Return Value: L<$resultset|/search>
356 This method does the same exact thing as search() except it will
357 always return a resultset, even in list context.
364 my $rsrc = $self->result_source;
365 my ($call_cond, $call_attrs);
367 # Special-case handling for (undef, undef) or (undef)
368 # Note that (foo => undef) is valid deprecated syntax
369 @_ = () if not scalar grep { defined $_ } @_;
375 # fish out attrs in the ($condref, $attr) case
376 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
377 ($call_cond, $call_attrs) = @_;
380 $self->throw_exception('Odd number of arguments to search')
384 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
385 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
387 for my $i (0 .. $#_) {
389 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
390 if (! defined $_[$i] or ref $_[$i] ne '');
396 # see if we can keep the cache (no $rs changes)
398 my %safe = (alias => 1, cache => 1);
399 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
402 ref $call_cond eq 'HASH' && ! keys %$call_cond
404 ref $call_cond eq 'ARRAY' && ! @$call_cond
406 $cache = $self->get_cache;
409 my $old_attrs = { %{$self->{attrs}} };
410 my $old_having = delete $old_attrs->{having};
411 my $old_where = delete $old_attrs->{where};
413 my $new_attrs = { %$old_attrs };
415 # take care of call attrs (only if anything is changing)
416 if ($call_attrs and keys %$call_attrs) {
418 # copy for _normalize_selection
419 $call_attrs = { %$call_attrs };
421 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
423 # reset the current selector list if new selectors are supplied
424 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
425 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
428 # Normalize the new selector list (operates on the passed-in attr structure)
429 # Need to do it on every chain instead of only once on _resolved_attrs, in
430 # order to allow detection of empty vs partial 'as'
431 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
432 if $old_attrs->{_dark_selector};
433 $self->_normalize_selection ($call_attrs);
435 # start with blind overwriting merge, exclude selector attrs
436 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
437 delete @{$new_attrs}{@selector_attrs};
439 for (@selector_attrs) {
440 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
441 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
444 # older deprecated name, use only if {columns} is not there
445 if (my $c = delete $new_attrs->{cols}) {
446 if ($new_attrs->{columns}) {
447 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
450 $new_attrs->{columns} = $c;
455 # join/prefetch use their own crazy merging heuristics
456 foreach my $key (qw/join prefetch/) {
457 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
458 if exists $call_attrs->{$key};
461 # stack binds together
462 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
466 for ($old_where, $call_cond) {
468 $new_attrs->{where} = $self->_stack_cond (
469 $_, $new_attrs->{where}
474 if (defined $old_having) {
475 $new_attrs->{having} = $self->_stack_cond (
476 $old_having, $new_attrs->{having}
480 my $rs = (ref $self)->new($rsrc, $new_attrs);
482 $rs->set_cache($cache) if ($cache);
488 sub _normalize_selection {
489 my ($self, $attrs) = @_;
492 $attrs->{'+columns'} = $self->_merge_attr($attrs->{'+columns'}, delete $attrs->{include_columns})
493 if exists $attrs->{include_columns};
495 # columns are always placed first, however
497 # Keep the X vs +X separation until _resolved_attrs time - this allows to
498 # delay the decision on whether to use a default select list ($rsrc->columns)
499 # allowing stuff like the remove_columns helper to work
501 # select/as +select/+as pairs need special handling - the amount of select/as
502 # elements in each pair does *not* have to be equal (think multicolumn
503 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
504 # supplied at all) - try to infer the alias, either from the -as parameter
505 # of the selector spec, or use the parameter whole if it looks like a column
506 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
507 # is ok as well), but make sure no more additions to the 'as' chain take place
508 for my $pref ('', '+') {
510 my ($sel, $as) = map {
511 my $key = "${pref}${_}";
513 my $val = [ ref $attrs->{$key} eq 'ARRAY'
515 : $attrs->{$key} || ()
517 delete $attrs->{$key};
521 if (! @$as and ! @$sel ) {
524 elsif (@$as and ! @$sel) {
525 $self->throw_exception(
526 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
530 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
531 # if any @$as has been supplied we assume the user knows what (s)he is doing
532 # and blindly keep stacking up pieces
533 unless ($attrs->{_dark_selector}) {
536 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
537 push @$as, $_->{-as};
539 # assume any plain no-space, no-parenthesis string to be a column spec
540 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
541 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
544 # if all else fails - raise a flag that no more aliasing will be allowed
546 $attrs->{_dark_selector} = {
548 string => ($dark_sel_dumper ||= do {
549 require Data::Dumper::Concise;
550 Data::Dumper::Concise::DumperObject()->Indent(0);
551 })->Values([$_])->Dump
559 elsif (@$as < @$sel) {
560 $self->throw_exception(
561 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
564 elsif ($pref and $attrs->{_dark_selector}) {
565 $self->throw_exception(
566 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
572 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
573 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
578 my ($self, $left, $right) = @_;
580 # collapse single element top-level conditions
581 # (single pass only, unlikely to need recursion)
582 for ($left, $right) {
583 if (ref $_ eq 'ARRAY') {
591 elsif (ref $_ eq 'HASH') {
592 my ($first, $more) = keys %$_;
595 if (! defined $first) {
599 elsif (! defined $more) {
600 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
603 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
610 # merge hashes with weeding out of duplicates (simple cases only)
611 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
613 # shallow copy to destroy
614 $right = { %$right };
615 for (grep { exists $right->{$_} } keys %$left) {
616 # the use of eq_deeply here is justified - the rhs of an
617 # expression can contain a lot of twisted weird stuff
618 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
621 $right = undef unless keys %$right;
625 if (defined $left xor defined $right) {
626 return defined $left ? $left : $right;
628 elsif (! defined $left) {
632 return { -and => [ $left, $right ] };
636 =head2 search_literal
638 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
639 should only be used in that context. C<search_literal> is a convenience
640 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
641 want to ensure columns are bound correctly, use L</search>.
643 See L<DBIx::Class::Manual::Cookbook/Searching> and
644 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
645 require C<search_literal>.
649 =item Arguments: $sql_fragment, @standalone_bind_values
651 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
655 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
656 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
658 Pass a literal chunk of SQL to be added to the conditional part of the
661 Example of how to use C<search> instead of C<search_literal>
663 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
664 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
669 my ($self, $sql, @bind) = @_;
671 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
674 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
681 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
683 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
687 Finds and returns a single row based on supplied criteria. Takes either a
688 hashref with the same format as L</create> (including inference of foreign
689 keys from related objects), or a list of primary key values in the same
690 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
691 declaration on the L</result_source>.
693 In either case an attempt is made to combine conditions already existing on
694 the resultset with the condition passed to this method.
696 To aid with preparing the correct query for the storage you may supply the
697 C<key> attribute, which is the name of a
698 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
699 unique constraint corresponding to the
700 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
701 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
702 to construct a query that satisfies the named unique constraint fully (
703 non-NULL values for each column member of the constraint) an exception is
706 If no C<key> is specified, the search is carried over all unique constraints
707 which are fully defined by the available condition.
709 If no such constraint is found, C<find> currently defaults to a simple
710 C<< search->(\%column_values) >> which may or may not do what you expect.
711 Note that this fallback behavior may be deprecated in further versions. If
712 you need to search with arbitrary conditions - use L</search>. If the query
713 resulting from this fallback produces more than one row, a warning to the
714 effect is issued, though only the first row is constructed and returned as
717 In addition to C<key>, L</find> recognizes and applies standard
718 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
720 Note that if you have extra concerns about the correctness of the resulting
721 query you need to specify the C<key> attribute and supply the entire condition
722 as an argument to find (since it is not always possible to perform the
723 combination of the resultset condition with the supplied one, especially if
724 the resultset condition contains literal sql).
726 For example, to find a row by its primary key:
728 my $cd = $schema->resultset('CD')->find(5);
730 You can also find a row by a specific unique constraint:
732 my $cd = $schema->resultset('CD')->find(
734 artist => 'Massive Attack',
735 title => 'Mezzanine',
737 { key => 'cd_artist_title' }
740 See also L</find_or_create> and L</update_or_create>.
746 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
748 my $rsrc = $self->result_source;
751 if (exists $attrs->{key}) {
752 $constraint_name = defined $attrs->{key}
754 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
758 # Parse out the condition from input
761 if (ref $_[0] eq 'HASH') {
762 $call_cond = { %{$_[0]} };
765 # if only values are supplied we need to default to 'primary'
766 $constraint_name = 'primary' unless defined $constraint_name;
768 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
770 $self->throw_exception(
771 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
774 $self->throw_exception (
775 'find() expects either a column/value hashref, or a list of values '
776 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
777 ) unless @c_cols == @_;
780 @{$call_cond}{@c_cols} = @_;
784 for my $key (keys %$call_cond) {
786 my $keyref = ref($call_cond->{$key})
788 my $relinfo = $rsrc->relationship_info($key)
790 my $val = delete $call_cond->{$key};
792 next if $keyref eq 'ARRAY'; # has_many for multi_create
794 my $rel_q = $rsrc->_resolve_condition(
795 $relinfo->{cond}, $val, $key, $key
797 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
798 @related{keys %$rel_q} = values %$rel_q;
802 # relationship conditions take precedence (?)
803 @{$call_cond}{keys %related} = values %related;
805 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
807 if (defined $constraint_name) {
808 $final_cond = $self->_qualify_cond_columns (
810 $self->_build_unique_cond (
818 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
819 # This means that we got here after a merger of relationship conditions
820 # in ::Relationship::Base::search_related (the row method), and furthermore
821 # the relationship is of the 'single' type. This means that the condition
822 # provided by the relationship (already attached to $self) is sufficient,
823 # as there can be only one row in the database that would satisfy the
827 # no key was specified - fall down to heuristics mode:
828 # run through all unique queries registered on the resultset, and
829 # 'OR' all qualifying queries together
830 my (@unique_queries, %seen_column_combinations);
831 for my $c_name ($rsrc->unique_constraint_names) {
832 next if $seen_column_combinations{
833 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
836 push @unique_queries, try {
837 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
841 $final_cond = @unique_queries
842 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
843 : $self->_non_unique_find_fallback ($call_cond, $attrs)
847 # Run the query, passing the result_class since it should propagate for find
848 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
849 if ($rs->_resolved_attrs->{collapse}) {
851 carp "Query returned more than one row" if $rs->next;
859 # This is a stop-gap method as agreed during the discussion on find() cleanup:
860 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
862 # It is invoked when find() is called in legacy-mode with insufficiently-unique
863 # condition. It is provided for overrides until a saner way forward is devised
865 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
866 # the road. Please adjust your tests accordingly to catch this situation early
867 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
869 # The method will not be removed without an adequately complete replacement
870 # for strict-mode enforcement
871 sub _non_unique_find_fallback {
872 my ($self, $cond, $attrs) = @_;
874 return $self->_qualify_cond_columns(
876 exists $attrs->{alias}
878 : $self->{attrs}{alias}
883 sub _qualify_cond_columns {
884 my ($self, $cond, $alias) = @_;
886 my %aliased = %$cond;
887 for (keys %aliased) {
888 $aliased{"$alias.$_"} = delete $aliased{$_}
895 sub _build_unique_cond {
896 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
898 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
900 # combination may fail if $self->{cond} is non-trivial
901 my ($final_cond) = try {
902 $self->_merge_with_rscond ($extra_cond)
907 # trim out everything not in $columns
908 $final_cond = { map {
909 exists $final_cond->{$_}
910 ? ( $_ => $final_cond->{$_} )
914 if (my @missing = grep
915 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
918 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
920 join (', ', map { "'$_'" } @missing),
927 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
929 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
931 carp_unique ( sprintf (
932 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
933 . 'values in column(s): %s). This is almost certainly not what you wanted, '
934 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
936 join (', ', map { "'$_'" } @undefs),
943 =head2 search_related
947 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
949 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
953 $new_rs = $cd_rs->search_related('artist', {
957 Searches the specified relationship, optionally specifying a condition and
958 attributes for matching records. See L</ATTRIBUTES> for more information.
960 In list context, C<< ->all() >> is called implicitly on the resultset, thus
961 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
963 See also L</search_related_rs>.
968 return shift->related_resultset(shift)->search(@_);
971 =head2 search_related_rs
973 This method works exactly the same as search_related, except that
974 it guarantees a resultset, even in list context.
978 sub search_related_rs {
979 return shift->related_resultset(shift)->search_rs(@_);
986 =item Arguments: none
988 =item Return Value: L<$cursor|DBIx::Class::Cursor>
992 Returns a storage-driven cursor to the given resultset. See
993 L<DBIx::Class::Cursor> for more information.
1000 return $self->{cursor} ||= do {
1001 my $attrs = { %{$self->_resolved_attrs } };
1002 $self->result_source->storage->select(
1003 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1012 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1014 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1018 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1020 Inflates the first result without creating a cursor if the resultset has
1021 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1024 While this method can take an optional search condition (just like L</search>)
1025 being a fast-code-path it does not recognize search attributes. If you need to
1026 add extra joins or similar, call L</search> and then chain-call L</single> on the
1027 L<DBIx::Class::ResultSet> returned.
1033 As of 0.08100, this method enforces the assumption that the preceding
1034 query returns only one row. If more than one row is returned, you will receive
1037 Query returned more than one row
1039 In this case, you should be using L</next> or L</find> instead, or if you really
1040 know what you are doing, use the L</rows> attribute to explicitly limit the size
1043 This method will also throw an exception if it is called on a resultset prefetching
1044 has_many, as such a prefetch implies fetching multiple rows from the database in
1045 order to assemble the resulting object.
1052 my ($self, $where) = @_;
1054 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1057 my $attrs = { %{$self->_resolved_attrs} };
1059 $self->throw_exception(
1060 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
1061 ) if $attrs->{collapse};
1064 if (defined $attrs->{where}) {
1067 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1068 $where, delete $attrs->{where} ]
1071 $attrs->{where} = $where;
1075 my $data = [ $self->result_source->storage->select_single(
1076 $attrs->{from}, $attrs->{select},
1077 $attrs->{where}, $attrs
1079 return undef unless @$data;
1080 $self->{_stashed_rows} = [ $data ];
1081 $self->_construct_results->[0];
1087 # Recursively collapse the query, accumulating values for each column.
1089 sub _collapse_query {
1090 my ($self, $query, $collapsed) = @_;
1094 if (ref $query eq 'ARRAY') {
1095 foreach my $subquery (@$query) {
1096 next unless ref $subquery; # -or
1097 $collapsed = $self->_collapse_query($subquery, $collapsed);
1100 elsif (ref $query eq 'HASH') {
1101 if (keys %$query and (keys %$query)[0] eq '-and') {
1102 foreach my $subquery (@{$query->{-and}}) {
1103 $collapsed = $self->_collapse_query($subquery, $collapsed);
1107 foreach my $col (keys %$query) {
1108 my $value = $query->{$col};
1109 $collapsed->{$col}{$value}++;
1121 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1123 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1127 my $max_length = $rs->get_column('length')->max;
1129 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1134 my ($self, $column) = @_;
1135 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1143 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1145 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1149 # WHERE title LIKE '%blue%'
1150 $cd_rs = $rs->search_like({ title => '%blue%'});
1152 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1153 that this is simply a convenience method retained for ex Class::DBI users.
1154 You most likely want to use L</search> with specific operators.
1156 For more information, see L<DBIx::Class::Manual::Cookbook>.
1158 This method is deprecated and will be removed in 0.09. Use L</search()>
1159 instead. An example conversion is:
1161 ->search_like({ foo => 'bar' });
1165 ->search({ foo => { like => 'bar' } });
1172 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1173 .' Instead use ->search({ x => { -like => "y%" } })'
1174 .' (note the outer pair of {}s - they are important!)'
1176 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1177 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1178 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1179 return $class->search($query, { %$attrs });
1186 =item Arguments: $first, $last
1188 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1192 Returns a resultset or object list representing a subset of elements from the
1193 resultset slice is called on. Indexes are from 0, i.e., to get the first
1194 three records, call:
1196 my ($one, $two, $three) = $rs->slice(0, 2);
1201 my ($self, $min, $max) = @_;
1202 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1203 $attrs->{offset} = $self->{attrs}{offset} || 0;
1204 $attrs->{offset} += $min;
1205 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1206 return $self->search(undef, $attrs);
1207 #my $slice = (ref $self)->new($self->result_source, $attrs);
1208 #return (wantarray ? $slice->all : $slice);
1215 =item Arguments: none
1217 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1221 Returns the next element in the resultset (C<undef> is there is none).
1223 Can be used to efficiently iterate over records in the resultset:
1225 my $rs = $schema->resultset('CD')->search;
1226 while (my $cd = $rs->next) {
1230 Note that you need to store the resultset object, and call C<next> on it.
1231 Calling C<< resultset('Table')->next >> repeatedly will always return the
1232 first record from the resultset.
1239 if (my $cache = $self->get_cache) {
1240 $self->{all_cache_position} ||= 0;
1241 return $cache->[$self->{all_cache_position}++];
1244 if ($self->{attrs}{cache}) {
1245 delete $self->{pager};
1246 $self->{all_cache_position} = 1;
1247 return ($self->all)[0];
1250 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1252 $self->{_stashed_results} = $self->_construct_results
1255 return shift @{$self->{_stashed_results}};
1258 # Constructs as many results as it can in one pass while respecting
1259 # cursor laziness. Several modes of operation:
1261 # * Always builds everything present in @{$self->{_stashed_rows}}
1262 # * If called with $fetch_all true - pulls everything off the cursor and
1263 # builds all result structures (or objects) in one pass
1264 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1265 # and if the resultset is ordered properly by the left side:
1266 # * Fetches stuff off the cursor until the "master object" changes,
1267 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1269 # * Just fetches, and collapses/constructs everything as if $fetch_all
1270 # was requested (there is no other way to collapse except for an
1272 # * If no collapse is requested - just get the next row, construct and
1274 sub _construct_results {
1275 my ($self, $fetch_all) = @_;
1277 my $rsrc = $self->result_source;
1278 my $attrs = $self->_resolved_attrs;
1280 if (!$fetch_all and ! $attrs->{order_by} and $attrs->{collapse}) {
1281 # default order for collapsing unless the user asked for something
1282 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} $rsrc->primary_columns ];
1283 $attrs->{_ordered_for_collapse} = 1;
1284 $attrs->{_order_is_artificial} = 1;
1287 my $cursor = $self->cursor;
1289 # this will be used as both initial raw-row collector AND as a RV of
1290 # _construct_results. Not regrowing the array twice matters a lot...
1291 # a surprising amount actually
1292 my $rows = delete $self->{_stashed_rows};
1295 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1296 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1298 elsif( $attrs->{collapse} ) {
1300 $attrs->{_ordered_for_collapse} = (!$attrs->{order_by}) ? 0 : do {
1301 my $st = $rsrc->schema->storage;
1304 ( $st->_extract_order_criteria($attrs->{order_by}) )
1307 my $colinfos = $st->_resolve_column_info($attrs->{from}, \@ord_cols);
1309 for (0 .. $#ord_cols) {
1311 ! $colinfos->{$ord_cols[$_]}
1313 $colinfos->{$ord_cols[$_]}{-result_source} != $rsrc
1315 splice @ord_cols, $_;
1320 # since all we check here are the start of the order_by belonging to the
1321 # top level $rsrc, a present identifying set will mean that the resultset
1322 # is ordered by its leftmost table in a tsable manner
1323 (@ord_cols and $rsrc->_identifying_column_set({ map
1324 { $colinfos->{$_}{-colname} => $colinfos->{$_} }
1327 } unless defined $attrs->{_ordered_for_collapse};
1329 if (! $attrs->{_ordered_for_collapse}) {
1332 # instead of looping over ->next, use ->all in stealth mode
1333 # *without* calling a ->reset afterwards
1334 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1335 if (! $cursor->{_done}) {
1336 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1337 $cursor->{_done} = 1;
1342 if (! $fetch_all and ! @{$rows||[]} ) {
1343 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1344 if (scalar (my @r = $cursor->next) ) {
1349 return undef unless @{$rows||[]};
1351 my @extra_collapser_args;
1352 if ($attrs->{collapse} and ! $fetch_all ) {
1354 @extra_collapser_args = (
1355 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1356 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1357 ($self->{_stashed_rows} = []), # where does it stuff excess
1361 # hotspot - skip the setter
1362 my $res_class = $self->_result_class;
1364 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1365 $res_class->can ('inflate_result')
1366 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1369 my $infmap = $attrs->{as};
1372 $self->{_result_inflator}{is_core_row} = ( (
1375 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1376 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1378 $self->{_result_inflator}{is_hri} = ( (
1379 ! $self->{_result_inflator}{is_core_row}
1382 require DBIx::Class::ResultClass::HashRefInflator
1384 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1386 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1389 if (! $attrs->{_related_results_construction}) {
1390 # construct a much simpler array->hash folder for the one-table cases right here
1391 if ($self->{_result_inflator}{is_hri}) {
1392 for my $r (@$rows) {
1393 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1396 # FIXME SUBOPTIMAL this is a very very very hot spot
1397 # while rather optimal we can *still* do much better, by
1398 # building a smarter Row::inflate_result(), and
1399 # switch to feeding it data via a much leaner interface
1401 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1402 # this particular resultset size
1403 elsif (@$rows < 60) {
1404 for my $r (@$rows) {
1405 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1410 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1411 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1415 # Special-case multi-object HRI (we always prune, and there is no $inflator_cref pass)
1416 elsif ($self->{_result_inflator}{is_hri}) {
1417 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1419 inflate_map => $infmap,
1420 selection => $attrs->{select},
1421 collapse => $attrs->{collapse},
1422 premultiplied => $attrs->{_main_source_premultiplied},
1424 prune_null_branches => 1,
1425 }) )->($rows, @extra_collapser_args);
1427 # Regular multi-object
1429 my $parser_type = $self->{_result_inflator}{is_core_row} ? 'classic_pruning' : 'classic_nonpruning';
1431 ( $self->{_row_parser}{$parser_type} ||= $rsrc->_mk_row_parser({
1433 inflate_map => $infmap,
1434 selection => $attrs->{select},
1435 collapse => $attrs->{collapse},
1436 premultiplied => $attrs->{_main_source_premultiplied},
1437 prune_null_branches => $self->{_result_inflator}{is_core_row},
1438 }) )->($rows, @extra_collapser_args);
1440 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1446 =head2 result_source
1450 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1452 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1456 An accessor for the primary ResultSource object from which this ResultSet
1463 =item Arguments: $result_class?
1465 =item Return Value: $result_class
1469 An accessor for the class to use when creating result objects. Defaults to
1470 C<< result_source->result_class >> - which in most cases is the name of the
1471 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1473 Note that changing the result_class will also remove any components
1474 that were originally loaded in the source class via
1475 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1476 in the original source class will not run.
1481 my ($self, $result_class) = @_;
1482 if ($result_class) {
1484 # don't fire this for an object
1485 $self->ensure_class_loaded($result_class)
1486 unless ref($result_class);
1488 if ($self->get_cache) {
1489 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1491 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1492 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1493 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1496 $self->_result_class($result_class);
1498 delete $self->{_result_inflator};
1500 $self->_result_class;
1507 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1509 =item Return Value: $count
1513 Performs an SQL C<COUNT> with the same query as the resultset was built
1514 with to find the number of elements. Passing arguments is equivalent to
1515 C<< $rs->search ($cond, \%attrs)->count >>
1521 return $self->search(@_)->count if @_ and defined $_[0];
1522 return scalar @{ $self->get_cache } if $self->get_cache;
1524 my $attrs = { %{ $self->_resolved_attrs } };
1526 # this is a little optimization - it is faster to do the limit
1527 # adjustments in software, instead of a subquery
1528 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1531 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1532 $crs = $self->_count_subq_rs ($attrs);
1535 $crs = $self->_count_rs ($attrs);
1537 my $count = $crs->next;
1539 $count -= $offset if $offset;
1540 $count = $rows if $rows and $rows < $count;
1541 $count = 0 if ($count < 0);
1550 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1552 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1556 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1557 This can be very handy for subqueries:
1559 ->search( { amount => $some_rs->count_rs->as_query } )
1561 As with regular resultsets the SQL query will be executed only after
1562 the resultset is accessed via L</next> or L</all>. That would return
1563 the same single value obtainable via L</count>.
1569 return $self->search(@_)->count_rs if @_;
1571 # this may look like a lack of abstraction (count() does about the same)
1572 # but in fact an _rs *must* use a subquery for the limits, as the
1573 # software based limiting can not be ported if this $rs is to be used
1574 # in a subquery itself (i.e. ->as_query)
1575 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1576 return $self->_count_subq_rs;
1579 return $self->_count_rs;
1584 # returns a ResultSetColumn object tied to the count query
1587 my ($self, $attrs) = @_;
1589 my $rsrc = $self->result_source;
1590 $attrs ||= $self->_resolved_attrs;
1592 my $tmp_attrs = { %$attrs };
1593 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1594 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1596 # overwrite the selector (supplied by the storage)
1597 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1598 $tmp_attrs->{as} = 'count';
1600 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1606 # same as above but uses a subquery
1608 sub _count_subq_rs {
1609 my ($self, $attrs) = @_;
1611 my $rsrc = $self->result_source;
1612 $attrs ||= $self->_resolved_attrs;
1614 my $sub_attrs = { %$attrs };
1615 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1616 delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/};
1618 # if we multi-prefetch we group_by something unique, as this is what we would
1619 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1620 if ( $attrs->{collapse} ) {
1621 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1622 $rsrc->_identifying_column_set || $self->throw_exception(
1623 'Unable to construct a unique group_by criteria properly collapsing the '
1624 . 'has_many prefetch before count()'
1629 # Calculate subquery selector
1630 if (my $g = $sub_attrs->{group_by}) {
1632 my $sql_maker = $rsrc->storage->sql_maker;
1634 # necessary as the group_by may refer to aliased functions
1636 for my $sel (@{$attrs->{select}}) {
1637 $sel_index->{$sel->{-as}} = $sel
1638 if (ref $sel eq 'HASH' and $sel->{-as});
1641 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1642 # also look for named aggregates referred in the having clause
1643 # having often contains scalarrefs - thus parse it out entirely
1645 if ($attrs->{having}) {
1646 local $sql_maker->{having_bind};
1647 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1648 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1649 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1650 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1651 # if we don't unset it we screw up retarded but unfortunately working
1652 # 'MAX(foo.bar)' => { '>', 3 }
1653 $sql_maker->{name_sep} = '';
1656 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1658 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1661 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1662 # and if all fails for an utterly naive quoted scalar-with-function
1663 while ($having_sql =~ /
1664 $rquote $sep $lquote (.+?) $rquote
1666 [\s,] \w+ \. (\w+) [\s,]
1668 [\s,] $lquote (.+?) $rquote [\s,]
1670 my $part = $1 || $2 || $3; # one of them matched if we got here
1671 unless ($seen_having{$part}++) {
1678 my $colpiece = $sel_index->{$_} || $_;
1680 # unqualify join-based group_by's. Arcane but possible query
1681 # also horrible horrible hack to alias a column (not a func.)
1682 # (probably need to introduce SQLA syntax)
1683 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1686 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1688 push @{$sub_attrs->{select}}, $colpiece;
1692 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1693 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1696 return $rsrc->resultset_class
1697 ->new ($rsrc, $sub_attrs)
1699 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1700 ->get_column ('count');
1704 =head2 count_literal
1706 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1707 should only be used in that context. See L</search_literal> for further info.
1711 =item Arguments: $sql_fragment, @standalone_bind_values
1713 =item Return Value: $count
1717 Counts the results in a literal query. Equivalent to calling L</search_literal>
1718 with the passed arguments, then L</count>.
1722 sub count_literal { shift->search_literal(@_)->count; }
1728 =item Arguments: none
1730 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1734 Returns all elements in the resultset.
1741 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1744 delete @{$self}{qw/_stashed_rows _stashed_results/};
1746 if (my $c = $self->get_cache) {
1750 $self->cursor->reset;
1752 my $objs = $self->_construct_results('fetch_all') || [];
1754 $self->set_cache($objs) if $self->{attrs}{cache};
1763 =item Arguments: none
1765 =item Return Value: $self
1769 Resets the resultset's cursor, so you can iterate through the elements again.
1770 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1778 delete @{$self}{qw/_stashed_rows _stashed_results/};
1779 $self->{all_cache_position} = 0;
1780 $self->cursor->reset;
1788 =item Arguments: none
1790 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1794 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1795 an object for the first result (or C<undef> if the resultset is empty).
1800 return $_[0]->reset->next;
1806 # Determines whether and what type of subquery is required for the $rs operation.
1807 # If grouping is necessary either supplies its own, or verifies the current one
1808 # After all is done delegates to the proper storage method.
1810 sub _rs_update_delete {
1811 my ($self, $op, $values) = @_;
1813 my $rsrc = $self->result_source;
1814 my $storage = $rsrc->schema->storage;
1816 my $attrs = { %{$self->_resolved_attrs} };
1818 my $join_classifications;
1819 my $existing_group_by = delete $attrs->{group_by};
1821 # do we need a subquery for any reason?
1823 defined $existing_group_by
1825 # if {from} is unparseable wrap a subq
1826 ref($attrs->{from}) ne 'ARRAY'
1828 # limits call for a subq
1829 $self->_has_resolved_attr(qw/rows offset/)
1832 # simplify the joinmap, so we can further decide if a subq is necessary
1833 if (!$needs_subq and @{$attrs->{from}} > 1) {
1834 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1836 # check if there are any joins left after the prune
1837 if ( @{$attrs->{from}} > 1 ) {
1838 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1839 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1845 # any non-pruneable joins imply subq
1846 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1850 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1852 (ref $attrs->{from}[0]) ne 'HASH'
1854 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1858 # do we need anything like a subquery?
1859 if (! $needs_subq) {
1860 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1861 # a condition containing 'me' or other table prefixes will not work
1862 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1864 my $sqla = $rsrc->storage->sql_maker;
1865 local $sqla->{_dequalify_idents} = 1;
1866 \[ $sqla->_recurse_where($self->{cond}) ];
1870 # we got this far - means it is time to wrap a subquery
1871 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1873 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1879 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1880 delete $attrs->{$_} for qw/collapse select _prefetch_selector_range as/;
1881 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1882 $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins
1883 my $subrs = (ref $self)->new($rsrc, $attrs);
1885 if (@$idcols == 1) {
1886 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1888 elsif ($storage->_use_multicolumn_in) {
1889 # no syntax for calling this properly yet
1890 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1891 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1892 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1897 # if all else fails - get all primary keys and operate over a ORed set
1898 # wrap in a transaction for consistency
1899 # this is where the group_by/multiplication starts to matter
1903 keys %{ $join_classifications->{multiplying} || {} }
1905 # make sure if there is a supplied group_by it matches the columns compiled above
1906 # perfectly. Anything else can not be sanely executed on most databases so croak
1907 # right then and there
1908 if ($existing_group_by) {
1909 my @current_group_by = map
1910 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1915 join ("\x00", sort @current_group_by)
1917 join ("\x00", sort @{$attrs->{columns}} )
1919 $self->throw_exception (
1920 "You have just attempted a $op operation on a resultset which does group_by"
1921 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1922 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1923 . ' kind of queries. Please retry the operation with a modified group_by or'
1924 . ' without using one at all.'
1929 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1932 $guard = $storage->txn_scope_guard;
1935 for my $row ($subrs->cursor->all) {
1937 { $idcols->[$_] => $row->[$_] }
1944 my $res = $storage->$op (
1946 $op eq 'update' ? $values : (),
1950 $guard->commit if $guard;
1959 =item Arguments: \%values
1961 =item Return Value: $underlying_storage_rv
1965 Sets the specified columns in the resultset to the supplied values in a
1966 single query. Note that this will not run any accessor/set_column/update
1967 triggers, nor will it update any result object instances derived from this
1968 resultset (this includes the contents of the L<resultset cache|/set_cache>
1969 if any). See L</update_all> if you need to execute any on-update
1970 triggers or cascades defined either by you or a
1971 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1973 The return value is a pass through of what the underlying
1974 storage backend returned, and may vary. See L<DBI/execute> for the most
1979 Note that L</update> does not process/deflate any of the values passed in.
1980 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1981 ensure manually that any value passed to this method will stringify to
1982 something the RDBMS knows how to deal with. A notable example is the
1983 handling of L<DateTime> objects, for more info see:
1984 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1989 my ($self, $values) = @_;
1990 $self->throw_exception('Values for update must be a hash')
1991 unless ref $values eq 'HASH';
1993 return $self->_rs_update_delete ('update', $values);
2000 =item Arguments: \%values
2002 =item Return Value: 1
2006 Fetches all objects and updates them one at a time via
2007 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2008 triggers, while L</update> will not.
2013 my ($self, $values) = @_;
2014 $self->throw_exception('Values for update_all must be a hash')
2015 unless ref $values eq 'HASH';
2017 my $guard = $self->result_source->schema->txn_scope_guard;
2018 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2027 =item Arguments: none
2029 =item Return Value: $underlying_storage_rv
2033 Deletes the rows matching this resultset in a single query. Note that this
2034 will not run any delete triggers, nor will it alter the
2035 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2036 derived from this resultset (this includes the contents of the
2037 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2038 execute any on-delete triggers or cascades defined either by you or a
2039 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2041 The return value is a pass through of what the underlying storage backend
2042 returned, and may vary. See L<DBI/execute> for the most common case.
2048 $self->throw_exception('delete does not accept any arguments')
2051 return $self->_rs_update_delete ('delete');
2058 =item Arguments: none
2060 =item Return Value: 1
2064 Fetches all objects and deletes them one at a time via
2065 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2066 triggers, while L</delete> will not.
2072 $self->throw_exception('delete_all does not accept any arguments')
2075 my $guard = $self->result_source->schema->txn_scope_guard;
2076 $_->delete for $self->all;
2085 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2087 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2091 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2098 The context of this method call has an important effect on what is
2099 submitted to storage. In void context data is fed directly to fastpath
2100 insertion routines provided by the underlying storage (most often
2101 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2102 L<insert|DBIx::Class::Row/insert> calls on the
2103 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2104 augmentation of these methods provided by components. For example if you
2105 are using something like L<DBIx::Class::UUIDColumns> to create primary
2106 keys for you, you will find that your PKs are empty. In this case you
2107 will have to explicitly force scalar or list context in order to create
2112 In non-void (scalar or list) context, this method is simply a wrapper
2113 for L</create>. Depending on list or scalar context either a list of
2114 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2115 containing these objects is returned.
2117 When supplying data in "arrayref of arrayrefs" invocation style, the
2118 first element should be a list of column names and each subsequent
2119 element should be a data value in the earlier specified column order.
2122 $Arstist_rs->populate([
2123 [ qw( artistid name ) ],
2124 [ 100, 'A Formally Unknown Singer' ],
2125 [ 101, 'A singer that jumped the shark two albums ago' ],
2126 [ 102, 'An actually cool singer' ],
2129 For the arrayref of hashrefs style each hashref should be a structure
2130 suitable for passing to L</create>. Multi-create is also permitted with
2133 $schema->resultset("Artist")->populate([
2134 { artistid => 4, name => 'Manufactured Crap', cds => [
2135 { title => 'My First CD', year => 2006 },
2136 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2139 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2140 { title => 'My parents sold me to a record company', year => 2005 },
2141 { title => 'Why Am I So Ugly?', year => 2006 },
2142 { title => 'I Got Surgery and am now Popular', year => 2007 }
2147 If you attempt a void-context multi-create as in the example above (each
2148 Artist also has the related list of CDs), and B<do not> supply the
2149 necessary autoinc foreign key information, this method will proxy to the
2150 less efficient L</create>, and then throw the Result objects away. In this
2151 case there are obviously no benefits to using this method over L</create>.
2158 # cruft placed in standalone method
2159 my $data = $self->_normalize_populate_args(@_);
2161 return unless @$data;
2163 if(defined wantarray) {
2164 my @created = map { $self->create($_) } @$data;
2165 return wantarray ? @created : \@created;
2168 my $first = $data->[0];
2170 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2171 # it relationship data
2172 my (@rels, @columns);
2173 my $rsrc = $self->result_source;
2174 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2175 for (keys %$first) {
2176 my $ref = ref $first->{$_};
2177 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2183 my @pks = $rsrc->primary_columns;
2185 ## do the belongs_to relationships
2186 foreach my $index (0..$#$data) {
2188 # delegate to create() for any dataset without primary keys with specified relationships
2189 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2191 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2192 my @ret = $self->populate($data);
2198 foreach my $rel (@rels) {
2199 next unless ref $data->[$index]->{$rel} eq "HASH";
2200 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2201 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2202 my $related = $result->result_source->_resolve_condition(
2203 $reverse_relinfo->{cond},
2209 delete $data->[$index]->{$rel};
2210 $data->[$index] = {%{$data->[$index]}, %$related};
2212 push @columns, keys %$related if $index == 0;
2216 ## inherit the data locked in the conditions of the resultset
2217 my ($rs_data) = $self->_merge_with_rscond({});
2218 delete @{$rs_data}{@columns};
2220 ## do bulk insert on current row
2221 $rsrc->storage->insert_bulk(
2223 [@columns, keys %$rs_data],
2224 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2227 ## do the has_many relationships
2228 foreach my $item (@$data) {
2232 foreach my $rel (@rels) {
2233 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2235 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2237 my $child = $main_row->$rel;
2239 my $related = $child->result_source->_resolve_condition(
2240 $rels->{$rel}{cond},
2246 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2247 my @populate = map { {%$_, %$related} } @rows_to_add;
2249 $child->populate( \@populate );
2256 # populate() argumnets went over several incarnations
2257 # What we ultimately support is AoH
2258 sub _normalize_populate_args {
2259 my ($self, $arg) = @_;
2261 if (ref $arg eq 'ARRAY') {
2265 elsif (ref $arg->[0] eq 'HASH') {
2268 elsif (ref $arg->[0] eq 'ARRAY') {
2270 my @colnames = @{$arg->[0]};
2271 foreach my $values (@{$arg}[1 .. $#$arg]) {
2272 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2278 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2285 =item Arguments: none
2287 =item Return Value: L<$pager|Data::Page>
2291 Returns a L<Data::Page> object for the current resultset. Only makes
2292 sense for queries with a C<page> attribute.
2294 To get the full count of entries for a paged resultset, call
2295 C<total_entries> on the L<Data::Page> object.
2302 return $self->{pager} if $self->{pager};
2304 my $attrs = $self->{attrs};
2305 if (!defined $attrs->{page}) {
2306 $self->throw_exception("Can't create pager for non-paged rs");
2308 elsif ($attrs->{page} <= 0) {
2309 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2311 $attrs->{rows} ||= 10;
2313 # throw away the paging flags and re-run the count (possibly
2314 # with a subselect) to get the real total count
2315 my $count_attrs = { %$attrs };
2316 delete @{$count_attrs}{qw/rows offset page pager/};
2318 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2320 require DBIx::Class::ResultSet::Pager;
2321 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2322 sub { $total_rs->count }, #lazy-get the total
2324 $self->{attrs}{page},
2332 =item Arguments: $page_number
2334 =item Return Value: L<$resultset|/search>
2338 Returns a resultset for the $page_number page of the resultset on which page
2339 is called, where each page contains a number of rows equal to the 'rows'
2340 attribute set on the resultset (10 by default).
2345 my ($self, $page) = @_;
2346 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2353 =item Arguments: \%col_data
2355 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2359 Creates a new result object in the resultset's result class and returns
2360 it. The row is not inserted into the database at this point, call
2361 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2362 will tell you whether the result object has been inserted or not.
2364 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2369 my ($self, $values) = @_;
2371 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2374 $self->throw_exception( "new_result expects a hashref" )
2375 unless (ref $values eq 'HASH');
2377 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2379 my $new = $self->result_class->new({
2381 ( @$cols_from_relations
2382 ? (-cols_from_relations => $cols_from_relations)
2385 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2389 reftype($new) eq 'HASH'
2395 carp_unique (sprintf (
2396 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2397 $self->result_class,
2404 # _merge_with_rscond
2406 # Takes a simple hash of K/V data and returns its copy merged with the
2407 # condition already present on the resultset. Additionally returns an
2408 # arrayref of value/condition names, which were inferred from related
2409 # objects (this is needed for in-memory related objects)
2410 sub _merge_with_rscond {
2411 my ($self, $data) = @_;
2413 my (%new_data, @cols_from_relations);
2415 my $alias = $self->{attrs}{alias};
2417 if (! defined $self->{cond}) {
2418 # just massage $data below
2420 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2421 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2422 @cols_from_relations = keys %new_data;
2424 elsif (ref $self->{cond} ne 'HASH') {
2425 $self->throw_exception(
2426 "Can't abstract implicit construct, resultset condition not a hash"
2430 # precendence must be given to passed values over values inherited from
2431 # the cond, so the order here is important.
2432 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2433 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2435 while ( my($col, $value) = each %implied ) {
2436 my $vref = ref $value;
2442 (keys %$value)[0] eq '='
2444 $new_data{$col} = $value->{'='};
2446 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2447 $new_data{$col} = $value;
2454 %{ $self->_remove_alias($data, $alias) },
2457 return (\%new_data, \@cols_from_relations);
2460 # _has_resolved_attr
2462 # determines if the resultset defines at least one
2463 # of the attributes supplied
2465 # used to determine if a subquery is neccessary
2467 # supports some virtual attributes:
2469 # This will scan for any joins being present on the resultset.
2470 # It is not a mere key-search but a deep inspection of {from}
2473 sub _has_resolved_attr {
2474 my ($self, @attr_names) = @_;
2476 my $attrs = $self->_resolved_attrs;
2480 for my $n (@attr_names) {
2481 if (grep { $n eq $_ } (qw/-join/) ) {
2482 $extra_checks{$n}++;
2486 my $attr = $attrs->{$n};
2488 next if not defined $attr;
2490 if (ref $attr eq 'HASH') {
2491 return 1 if keys %$attr;
2493 elsif (ref $attr eq 'ARRAY') {
2501 # a resolved join is expressed as a multi-level from
2503 $extra_checks{-join}
2505 ref $attrs->{from} eq 'ARRAY'
2507 @{$attrs->{from}} > 1
2515 # Recursively collapse the condition.
2517 sub _collapse_cond {
2518 my ($self, $cond, $collapsed) = @_;
2522 if (ref $cond eq 'ARRAY') {
2523 foreach my $subcond (@$cond) {
2524 next unless ref $subcond; # -or
2525 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2528 elsif (ref $cond eq 'HASH') {
2529 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2530 foreach my $subcond (@{$cond->{-and}}) {
2531 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2535 foreach my $col (keys %$cond) {
2536 my $value = $cond->{$col};
2537 $collapsed->{$col} = $value;
2547 # Remove the specified alias from the specified query hash. A copy is made so
2548 # the original query is not modified.
2551 my ($self, $query, $alias) = @_;
2553 my %orig = %{ $query || {} };
2556 foreach my $key (keys %orig) {
2558 $unaliased{$key} = $orig{$key};
2561 $unaliased{$1} = $orig{$key}
2562 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2572 =item Arguments: none
2574 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2578 Returns the SQL query and bind vars associated with the invocant.
2580 This is generally used as the RHS for a subquery.
2587 my $attrs = { %{ $self->_resolved_attrs } };
2592 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2593 # $sql also has no wrapping parenthesis in list ctx
2595 my $sqlbind = $self->result_source->storage
2596 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2605 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2607 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2611 my $artist = $schema->resultset('Artist')->find_or_new(
2612 { artist => 'fred' }, { key => 'artists' });
2614 $cd->cd_to_producer->find_or_new({ producer => $producer },
2615 { key => 'primary });
2617 Find an existing record from this resultset using L</find>. if none exists,
2618 instantiate a new result object and return it. The object will not be saved
2619 into your storage until you call L<DBIx::Class::Row/insert> on it.
2621 You most likely want this method when looking for existing rows using a unique
2622 constraint that is not the primary key, or looking for related rows.
2624 If you want objects to be saved immediately, use L</find_or_create> instead.
2626 B<Note>: Make sure to read the documentation of L</find> and understand the
2627 significance of the C<key> attribute, as its lack may skew your search, and
2628 subsequently result in spurious new objects.
2630 B<Note>: Take care when using C<find_or_new> with a table having
2631 columns with default values that you intend to be automatically
2632 supplied by the database (e.g. an auto_increment primary key column).
2633 In normal usage, the value of such columns should NOT be included at
2634 all in the call to C<find_or_new>, even when set to C<undef>.
2640 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2641 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2642 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2645 return $self->new_result($hash);
2652 =item Arguments: \%col_data
2654 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2658 Attempt to create a single new row or a row with multiple related rows
2659 in the table represented by the resultset (and related tables). This
2660 will not check for duplicate rows before inserting, use
2661 L</find_or_create> to do that.
2663 To create one row for this resultset, pass a hashref of key/value
2664 pairs representing the columns of the table and the values you wish to
2665 store. If the appropriate relationships are set up, foreign key fields
2666 can also be passed an object representing the foreign row, and the
2667 value will be set to its primary key.
2669 To create related objects, pass a hashref of related-object column values
2670 B<keyed on the relationship name>. If the relationship is of type C<multi>
2671 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2672 The process will correctly identify columns holding foreign keys, and will
2673 transparently populate them from the keys of the corresponding relation.
2674 This can be applied recursively, and will work correctly for a structure
2675 with an arbitrary depth and width, as long as the relationships actually
2676 exists and the correct column data has been supplied.
2678 Instead of hashrefs of plain related data (key/value pairs), you may
2679 also pass new or inserted objects. New objects (not inserted yet, see
2680 L</new_result>), will be inserted into their appropriate tables.
2682 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2684 Example of creating a new row.
2686 $person_rs->create({
2687 name=>"Some Person",
2688 email=>"somebody@someplace.com"
2691 Example of creating a new row and also creating rows in a related C<has_many>
2692 or C<has_one> resultset. Note Arrayref.
2695 { artistid => 4, name => 'Manufactured Crap', cds => [
2696 { title => 'My First CD', year => 2006 },
2697 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2702 Example of creating a new row and also creating a row in a related
2703 C<belongs_to> resultset. Note Hashref.
2706 title=>"Music for Silly Walks",
2709 name=>"Silly Musician",
2717 When subclassing ResultSet never attempt to override this method. Since
2718 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2719 lot of the internals simply never call it, so your override will be
2720 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2721 or L<DBIx::Class::Row/insert> depending on how early in the
2722 L</create> process you need to intervene. See also warning pertaining to
2730 my ($self, $attrs) = @_;
2731 $self->throw_exception( "create needs a hashref" )
2732 unless ref $attrs eq 'HASH';
2733 return $self->new_result($attrs)->insert;
2736 =head2 find_or_create
2740 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2742 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2746 $cd->cd_to_producer->find_or_create({ producer => $producer },
2747 { key => 'primary' });
2749 Tries to find a record based on its primary key or unique constraints; if none
2750 is found, creates one and returns that instead.
2752 my $cd = $schema->resultset('CD')->find_or_create({
2754 artist => 'Massive Attack',
2755 title => 'Mezzanine',
2759 Also takes an optional C<key> attribute, to search by a specific key or unique
2760 constraint. For example:
2762 my $cd = $schema->resultset('CD')->find_or_create(
2764 artist => 'Massive Attack',
2765 title => 'Mezzanine',
2767 { key => 'cd_artist_title' }
2770 B<Note>: Make sure to read the documentation of L</find> and understand the
2771 significance of the C<key> attribute, as its lack may skew your search, and
2772 subsequently result in spurious row creation.
2774 B<Note>: Because find_or_create() reads from the database and then
2775 possibly inserts based on the result, this method is subject to a race
2776 condition. Another process could create a record in the table after
2777 the find has completed and before the create has started. To avoid
2778 this problem, use find_or_create() inside a transaction.
2780 B<Note>: Take care when using C<find_or_create> with a table having
2781 columns with default values that you intend to be automatically
2782 supplied by the database (e.g. an auto_increment primary key column).
2783 In normal usage, the value of such columns should NOT be included at
2784 all in the call to C<find_or_create>, even when set to C<undef>.
2786 See also L</find> and L</update_or_create>. For information on how to declare
2787 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2789 If you need to know if an existing row was found or a new one created use
2790 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2791 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2794 my $cd = $schema->resultset('CD')->find_or_new({
2796 artist => 'Massive Attack',
2797 title => 'Mezzanine',
2801 if( !$cd->in_storage ) {
2808 sub find_or_create {
2810 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2811 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2812 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2815 return $self->create($hash);
2818 =head2 update_or_create
2822 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2824 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2828 $resultset->update_or_create({ col => $val, ... });
2830 Like L</find_or_create>, but if a row is found it is immediately updated via
2831 C<< $found_row->update (\%col_data) >>.
2834 Takes an optional C<key> attribute to search on a specific unique constraint.
2837 # In your application
2838 my $cd = $schema->resultset('CD')->update_or_create(
2840 artist => 'Massive Attack',
2841 title => 'Mezzanine',
2844 { key => 'cd_artist_title' }
2847 $cd->cd_to_producer->update_or_create({
2848 producer => $producer,
2854 B<Note>: Make sure to read the documentation of L</find> and understand the
2855 significance of the C<key> attribute, as its lack may skew your search, and
2856 subsequently result in spurious row creation.
2858 B<Note>: Take care when using C<update_or_create> with a table having
2859 columns with default values that you intend to be automatically
2860 supplied by the database (e.g. an auto_increment primary key column).
2861 In normal usage, the value of such columns should NOT be included at
2862 all in the call to C<update_or_create>, even when set to C<undef>.
2864 See also L</find> and L</find_or_create>. For information on how to declare
2865 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2867 If you need to know if an existing row was updated or a new one created use
2868 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2869 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2874 sub update_or_create {
2876 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2877 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2879 my $row = $self->find($cond, $attrs);
2881 $row->update($cond);
2885 return $self->create($cond);
2888 =head2 update_or_new
2892 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2894 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2898 $resultset->update_or_new({ col => $val, ... });
2900 Like L</find_or_new> but if a row is found it is immediately updated via
2901 C<< $found_row->update (\%col_data) >>.
2905 # In your application
2906 my $cd = $schema->resultset('CD')->update_or_new(
2908 artist => 'Massive Attack',
2909 title => 'Mezzanine',
2912 { key => 'cd_artist_title' }
2915 if ($cd->in_storage) {
2916 # the cd was updated
2919 # the cd is not yet in the database, let's insert it
2923 B<Note>: Make sure to read the documentation of L</find> and understand the
2924 significance of the C<key> attribute, as its lack may skew your search, and
2925 subsequently result in spurious new objects.
2927 B<Note>: Take care when using C<update_or_new> with a table having
2928 columns with default values that you intend to be automatically
2929 supplied by the database (e.g. an auto_increment primary key column).
2930 In normal usage, the value of such columns should NOT be included at
2931 all in the call to C<update_or_new>, even when set to C<undef>.
2933 See also L</find>, L</find_or_create> and L</find_or_new>.
2939 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2940 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2942 my $row = $self->find( $cond, $attrs );
2943 if ( defined $row ) {
2944 $row->update($cond);
2948 return $self->new_result($cond);
2955 =item Arguments: none
2957 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2961 Gets the contents of the cache for the resultset, if the cache is set.
2963 The cache is populated either by using the L</prefetch> attribute to
2964 L</search> or by calling L</set_cache>.
2976 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2978 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2982 Sets the contents of the cache for the resultset. Expects an arrayref
2983 of objects of the same class as those produced by the resultset. Note that
2984 if the cache is set, the resultset will return the cached objects rather
2985 than re-querying the database even if the cache attr is not set.
2987 The contents of the cache can also be populated by using the
2988 L</prefetch> attribute to L</search>.
2993 my ( $self, $data ) = @_;
2994 $self->throw_exception("set_cache requires an arrayref")
2995 if defined($data) && (ref $data ne 'ARRAY');
2996 $self->{all_cache} = $data;
3003 =item Arguments: none
3005 =item Return Value: undef
3009 Clears the cache for the resultset.
3014 shift->set_cache(undef);
3021 =item Arguments: none
3023 =item Return Value: true, if the resultset has been paginated
3031 return !!$self->{attrs}{page};
3038 =item Arguments: none
3040 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3048 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3051 =head2 related_resultset
3055 =item Arguments: $rel_name
3057 =item Return Value: L<$resultset|/search>
3061 Returns a related resultset for the supplied relationship name.
3063 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3067 sub related_resultset {
3068 my ($self, $rel) = @_;
3070 return $self->{related_resultsets}{$rel} ||= do {
3071 my $rsrc = $self->result_source;
3072 my $rel_info = $rsrc->relationship_info($rel);
3074 $self->throw_exception(
3075 "search_related: result source '" . $rsrc->source_name .
3076 "' has no such relationship $rel")
3079 my $attrs = $self->_chain_relationship($rel);
3081 my $join_count = $attrs->{seen_join}{$rel};
3083 my $alias = $self->result_source->storage
3084 ->relname_to_table_alias($rel, $join_count);
3086 # since this is search_related, and we already slid the select window inwards
3087 # (the select/as attrs were deleted in the beginning), we need to flip all
3088 # left joins to inner, so we get the expected results
3089 # read the comment on top of the actual function to see what this does
3090 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3093 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3094 delete @{$attrs}{qw(result_class alias)};
3098 if (my $cache = $self->get_cache) {
3099 $related_cache = [ map
3100 { @{$_->related_resultset($rel)->get_cache||[]} }
3105 my $rel_source = $rsrc->related_source($rel);
3109 # The reason we do this now instead of passing the alias to the
3110 # search_rs below is that if you wrap/overload resultset on the
3111 # source you need to know what alias it's -going- to have for things
3112 # to work sanely (e.g. RestrictWithObject wants to be able to add
3113 # extra query restrictions, and these may need to be $alias.)
3115 my $rel_attrs = $rel_source->resultset_attributes;
3116 local $rel_attrs->{alias} = $alias;
3118 $rel_source->resultset
3122 where => $attrs->{where},
3125 $new->set_cache($related_cache) if $related_cache;
3130 =head2 current_source_alias
3134 =item Arguments: none
3136 =item Return Value: $source_alias
3140 Returns the current table alias for the result source this resultset is built
3141 on, that will be used in the SQL query. Usually it is C<me>.
3143 Currently the source alias that refers to the result set returned by a
3144 L</search>/L</find> family method depends on how you got to the resultset: it's
3145 C<me> by default, but eg. L</search_related> aliases it to the related result
3146 source name (and keeps C<me> referring to the original result set). The long
3147 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3148 (and make this method unnecessary).
3150 Thus it's currently necessary to use this method in predefined queries (see
3151 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3152 source alias of the current result set:
3154 # in a result set class
3156 my ($self, $user) = @_;
3158 my $me = $self->current_source_alias;
3160 return $self->search({
3161 "$me.modified" => $user->id,
3167 sub current_source_alias {
3168 return (shift->{attrs} || {})->{alias} || 'me';
3171 =head2 as_subselect_rs
3175 =item Arguments: none
3177 =item Return Value: L<$resultset|/search>
3181 Act as a barrier to SQL symbols. The resultset provided will be made into a
3182 "virtual view" by including it as a subquery within the from clause. From this
3183 point on, any joined tables are inaccessible to ->search on the resultset (as if
3184 it were simply where-filtered without joins). For example:
3186 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3188 # 'x' now pollutes the query namespace
3190 # So the following works as expected
3191 my $ok_rs = $rs->search({'x.other' => 1});
3193 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3194 # def) we look for one row with contradictory terms and join in another table
3195 # (aliased 'x_2') which we never use
3196 my $broken_rs = $rs->search({'x.name' => 'def'});
3198 my $rs2 = $rs->as_subselect_rs;
3200 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3201 my $not_joined_rs = $rs2->search({'x.other' => 1});
3203 # works as expected: finds a 'table' row related to two x rows (abc and def)
3204 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3206 Another example of when one might use this would be to select a subset of
3207 columns in a group by clause:
3209 my $rs = $schema->resultset('Bar')->search(undef, {
3210 group_by => [qw{ id foo_id baz_id }],
3211 })->as_subselect_rs->search(undef, {
3212 columns => [qw{ id foo_id }]
3215 In the above example normally columns would have to be equal to the group by,
3216 but because we isolated the group by into a subselect the above works.
3220 sub as_subselect_rs {
3223 my $attrs = $self->_resolved_attrs;
3225 my $fresh_rs = (ref $self)->new (
3226 $self->result_source
3229 # these pieces will be locked in the subquery
3230 delete $fresh_rs->{cond};
3231 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3233 return $fresh_rs->search( {}, {
3235 $attrs->{alias} => $self->as_query,
3236 -alias => $attrs->{alias},
3237 -rsrc => $self->result_source,
3239 alias => $attrs->{alias},
3243 # This code is called by search_related, and makes sure there
3244 # is clear separation between the joins before, during, and
3245 # after the relationship. This information is needed later
3246 # in order to properly resolve prefetch aliases (any alias
3247 # with a relation_chain_depth less than the depth of the
3248 # current prefetch is not considered)
3250 # The increments happen twice per join. An even number means a
3251 # relationship specified via a search_related, whereas an odd
3252 # number indicates a join/prefetch added via attributes
3254 # Also this code will wrap the current resultset (the one we
3255 # chain to) in a subselect IFF it contains limiting attributes
3256 sub _chain_relationship {
3257 my ($self, $rel) = @_;
3258 my $source = $self->result_source;
3259 my $attrs = { %{$self->{attrs}||{}} };
3261 # we need to take the prefetch the attrs into account before we
3262 # ->_resolve_join as otherwise they get lost - captainL
3263 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3265 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
3267 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3270 my @force_subq_attrs = qw/offset rows group_by having/;
3273 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3275 $self->_has_resolved_attr (@force_subq_attrs)
3277 # Nuke the prefetch (if any) before the new $rs attrs
3278 # are resolved (prefetch is useless - we are wrapping
3279 # a subquery anyway).
3280 my $rs_copy = $self->search;
3281 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3282 $rs_copy->{attrs}{join},
3283 delete $rs_copy->{attrs}{prefetch},
3288 -alias => $attrs->{alias},
3289 $attrs->{alias} => $rs_copy->as_query,
3291 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3292 $seen->{-relation_chain_depth} = 0;
3294 elsif ($attrs->{from}) { #shallow copy suffices
3295 $from = [ @{$attrs->{from}} ];
3300 -alias => $attrs->{alias},
3301 $attrs->{alias} => $source->from,
3305 my $jpath = ($seen->{-relation_chain_depth})
3306 ? $from->[-1][0]{-join_path}
3309 my @requested_joins = $source->_resolve_join(
3316 push @$from, @requested_joins;
3318 $seen->{-relation_chain_depth}++;
3320 # if $self already had a join/prefetch specified on it, the requested
3321 # $rel might very well be already included. What we do in this case
3322 # is effectively a no-op (except that we bump up the chain_depth on
3323 # the join in question so we could tell it *is* the search_related)
3326 # we consider the last one thus reverse
3327 for my $j (reverse @requested_joins) {
3328 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3329 if ($rel eq $last_j) {
3330 $j->[0]{-relation_chain_depth}++;
3336 unless ($already_joined) {
3337 push @$from, $source->_resolve_join(
3345 $seen->{-relation_chain_depth}++;
3347 return {%$attrs, from => $from, seen_join => $seen};
3350 sub _resolved_attrs {
3352 return $self->{_attrs} if $self->{_attrs};
3354 my $attrs = { %{ $self->{attrs} || {} } };
3355 my $source = $self->result_source;
3356 my $alias = $attrs->{alias};
3358 # default selection list
3359 $attrs->{columns} = [ $source->columns ]
3360 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3362 # merge selectors together
3363 for (qw/columns select as/) {
3364 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3365 if $attrs->{$_} or $attrs->{"+$_"};
3368 # disassemble columns
3370 if (my $cols = delete $attrs->{columns}) {
3371 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3372 if (ref $c eq 'HASH') {
3373 for my $as (sort keys %$c) {
3374 push @sel, $c->{$as};
3385 # when trying to weed off duplicates later do not go past this point -
3386 # everything added from here on is unbalanced "anyone's guess" stuff
3387 my $dedup_stop_idx = $#as;
3389 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3391 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3392 if $attrs->{select};
3394 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3395 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3397 # disqualify all $alias.col as-bits (inflate-map mandated)
3398 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3400 # de-duplicate the result (remove *identical* select/as pairs)
3401 # and also die on duplicate {as} pointing to different {select}s
3402 # not using a c-style for as the condition is prone to shrinkage
3405 while ($i <= $dedup_stop_idx) {
3406 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3411 elsif ($seen->{$as[$i]}++) {
3412 $self->throw_exception(
3413 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3421 $attrs->{select} = \@sel;
3422 $attrs->{as} = \@as;
3424 $attrs->{from} ||= [{
3426 -alias => $self->{attrs}{alias},
3427 $self->{attrs}{alias} => $source->from,
3430 if ( $attrs->{join} || $attrs->{prefetch} ) {
3432 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3433 if ref $attrs->{from} ne 'ARRAY';
3435 my $join = (delete $attrs->{join}) || {};
3437 if ( defined $attrs->{prefetch} ) {
3438 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3441 $attrs->{from} = # have to copy here to avoid corrupting the original
3443 @{ $attrs->{from} },
3444 $source->_resolve_join(
3447 { %{ $attrs->{seen_join} || {} } },
3448 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3449 ? $attrs->{from}[-1][0]{-join_path}
3456 if ( defined $attrs->{order_by} ) {
3457 $attrs->{order_by} = (
3458 ref( $attrs->{order_by} ) eq 'ARRAY'
3459 ? [ @{ $attrs->{order_by} } ]
3460 : [ $attrs->{order_by} || () ]
3464 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3465 $attrs->{group_by} = [ $attrs->{group_by} ];
3468 # generate the distinct induced group_by early, as prefetch will be carried via a
3469 # subquery (since a group_by is present)
3470 if (delete $attrs->{distinct}) {
3471 if ($attrs->{group_by}) {
3472 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3475 # distinct affects only the main selection part, not what prefetch may
3477 $attrs->{group_by} = $source->storage->_group_over_selection (
3485 # generate selections based on the prefetch helper
3487 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3488 if defined $attrs->{prefetch};
3492 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3493 if $attrs->{_dark_selector};
3495 $attrs->{collapse} = 1;
3497 # this is a separate structure (we don't look in {from} directly)
3498 # as the resolver needs to shift things off the lists to work
3499 # properly (identical-prefetches on different branches)
3501 if (ref $attrs->{from} eq 'ARRAY') {
3503 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3505 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3506 next unless $j->[0]{-alias};
3507 next unless $j->[0]{-join_path};
3508 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3510 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3513 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3514 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3518 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3520 # we need to somehow mark which columns came from prefetch
3522 my $sel_end = $#{$attrs->{select}};
3523 $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
3526 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3527 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3530 if ( defined List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3531 $attrs->{_related_results_construction} = 1;
3534 $attrs->{collapse} = 0;
3537 # run through the resulting joinstructure (starting from our current slot)
3538 # and unset collapse if proven unnesessary
3540 # also while we are at it find out if the current root source has
3541 # been premultiplied by previous related_source chaining
3543 # this allows to predict whether a root object with all other relation
3544 # data set to NULL is in fact unique
3545 if ($attrs->{collapse}) {
3547 if (ref $attrs->{from} eq 'ARRAY') {
3549 if (@{$attrs->{from}} <= 1) {
3550 # no joins - no collapse
3551 $attrs->{collapse} = 0;
3554 # find where our table-spec starts
3555 my @fromlist = @{$attrs->{from}};
3557 my $t = shift @fromlist;
3560 # me vs join from-spec distinction - a ref means non-root
3561 if (ref $t eq 'ARRAY') {
3563 $is_multi ||= ! $t->{-is_single};
3565 last if ($t->{-alias} && $t->{-alias} eq $alias);
3566 $attrs->{_main_source_premultiplied} ||= $is_multi;
3569 # no non-singles remaining, nor any premultiplication - nothing to collapse
3571 ! $attrs->{_main_source_premultiplied}
3573 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3575 $attrs->{collapse} = 0;
3581 # if we can not analyze the from - err on the side of safety
3582 $attrs->{_main_source_premultiplied} = 1;
3586 # if both page and offset are specified, produce a combined offset
3587 # even though it doesn't make much sense, this is what pre 081xx has
3589 if (my $page = delete $attrs->{page}) {
3591 ($attrs->{rows} * ($page - 1))
3593 ($attrs->{offset} || 0)
3597 return $self->{_attrs} = $attrs;
3601 my ($self, $attr) = @_;
3603 if (ref $attr eq 'HASH') {
3604 return $self->_rollout_hash($attr);
3605 } elsif (ref $attr eq 'ARRAY') {
3606 return $self->_rollout_array($attr);
3612 sub _rollout_array {
3613 my ($self, $attr) = @_;
3616 foreach my $element (@{$attr}) {
3617 if (ref $element eq 'HASH') {
3618 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3619 } elsif (ref $element eq 'ARRAY') {
3620 # XXX - should probably recurse here
3621 push( @rolled_array, @{$self->_rollout_array($element)} );
3623 push( @rolled_array, $element );
3626 return \@rolled_array;
3630 my ($self, $attr) = @_;
3633 foreach my $key (keys %{$attr}) {
3634 push( @rolled_array, { $key => $attr->{$key} } );
3636 return \@rolled_array;
3639 sub _calculate_score {
3640 my ($self, $a, $b) = @_;
3642 if (defined $a xor defined $b) {
3645 elsif (not defined $a) {
3649 if (ref $b eq 'HASH') {
3650 my ($b_key) = keys %{$b};
3651 if (ref $a eq 'HASH') {
3652 my ($a_key) = keys %{$a};
3653 if ($a_key eq $b_key) {
3654 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3659 return ($a eq $b_key) ? 1 : 0;
3662 if (ref $a eq 'HASH') {
3663 my ($a_key) = keys %{$a};
3664 return ($b eq $a_key) ? 1 : 0;
3666 return ($b eq $a) ? 1 : 0;
3671 sub _merge_joinpref_attr {
3672 my ($self, $orig, $import) = @_;
3674 return $import unless defined($orig);
3675 return $orig unless defined($import);
3677 $orig = $self->_rollout_attr($orig);
3678 $import = $self->_rollout_attr($import);
3681 foreach my $import_element ( @{$import} ) {
3682 # find best candidate from $orig to merge $b_element into
3683 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3684 foreach my $orig_element ( @{$orig} ) {
3685 my $score = $self->_calculate_score( $orig_element, $import_element );
3686 if ($score > $best_candidate->{score}) {
3687 $best_candidate->{position} = $position;
3688 $best_candidate->{score} = $score;
3692 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3693 $import_key = '' if not defined $import_key;
3695 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3696 push( @{$orig}, $import_element );
3698 my $orig_best = $orig->[$best_candidate->{position}];
3699 # merge orig_best and b_element together and replace original with merged
3700 if (ref $orig_best ne 'HASH') {
3701 $orig->[$best_candidate->{position}] = $import_element;
3702 } elsif (ref $import_element eq 'HASH') {
3703 my ($key) = keys %{$orig_best};
3704 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3707 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3710 return @$orig ? $orig : ();
3718 require Hash::Merge;
3719 my $hm = Hash::Merge->new;
3721 $hm->specify_behavior({
3724 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3726 if ($defl xor $defr) {
3727 return [ $defl ? $_[0] : $_[1] ];
3732 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3736 return [$_[0], $_[1]];
3740 return $_[1] if !defined $_[0];
3741 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3742 return [$_[0], @{$_[1]}]
3745 return [] if !defined $_[0] and !keys %{$_[1]};
3746 return [ $_[1] ] if !defined $_[0];
3747 return [ $_[0] ] if !keys %{$_[1]};
3748 return [$_[0], $_[1]]
3753 return $_[0] if !defined $_[1];
3754 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3755 return [@{$_[0]}, $_[1]]
3758 my @ret = @{$_[0]} or return $_[1];
3759 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3760 my %idx = map { $_ => 1 } @ret;
3761 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3765 return [ $_[1] ] if ! @{$_[0]};
3766 return $_[0] if !keys %{$_[1]};
3767 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3768 return [ @{$_[0]}, $_[1] ];
3773 return [] if !keys %{$_[0]} and !defined $_[1];
3774 return [ $_[0] ] if !defined $_[1];
3775 return [ $_[1] ] if !keys %{$_[0]};
3776 return [$_[0], $_[1]]
3779 return [] if !keys %{$_[0]} and !@{$_[1]};
3780 return [ $_[0] ] if !@{$_[1]};
3781 return $_[1] if !keys %{$_[0]};
3782 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3783 return [ $_[0], @{$_[1]} ];
3786 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3787 return [ $_[0] ] if !keys %{$_[1]};
3788 return [ $_[1] ] if !keys %{$_[0]};
3789 return [ $_[0] ] if $_[0] eq $_[1];
3790 return [ $_[0], $_[1] ];
3793 } => 'DBIC_RS_ATTR_MERGER');
3797 return $hm->merge ($_[1], $_[2]);
3801 sub STORABLE_freeze {
3802 my ($self, $cloning) = @_;
3803 my $to_serialize = { %$self };
3805 # A cursor in progress can't be serialized (and would make little sense anyway)
3806 # the parser can be regenerated (and can't be serialized)
3807 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3809 # nor is it sensical to store a not-yet-fired-count pager
3810 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3811 delete $to_serialize->{pager};
3814 Storable::nfreeze($to_serialize);
3817 # need this hook for symmetry
3819 my ($self, $cloning, $serialized) = @_;
3821 %$self = %{ Storable::thaw($serialized) };
3827 =head2 throw_exception
3829 See L<DBIx::Class::Schema/throw_exception> for details.
3833 sub throw_exception {
3836 if (ref $self and my $rsrc = $self->result_source) {
3837 $rsrc->throw_exception(@_)
3840 DBIx::Class::Exception->throw(@_);
3848 # XXX: FIXME: Attributes docs need clearing up
3852 Attributes are used to refine a ResultSet in various ways when
3853 searching for data. They can be passed to any method which takes an
3854 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3857 Default attributes can be set on the result class using
3858 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3859 the CAVEATS on that feature before using it!)
3861 These are in no particular order:
3867 =item Value: ( $order_by | \@order_by | \%order_by )
3871 Which column(s) to order the results by.
3873 [The full list of suitable values is documented in
3874 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3877 If a single column name, or an arrayref of names is supplied, the
3878 argument is passed through directly to SQL. The hashref syntax allows
3879 for connection-agnostic specification of ordering direction:
3881 For descending order:
3883 order_by => { -desc => [qw/col1 col2 col3/] }
3885 For explicit ascending order:
3887 order_by => { -asc => 'col' }
3889 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3890 supported, although you are strongly encouraged to use the hashref
3891 syntax as outlined above.
3897 =item Value: \@columns | \%columns | $column
3901 Shortcut to request a particular set of columns to be retrieved. Each
3902 column spec may be a string (a table column name), or a hash (in which
3903 case the key is the C<as> value, and the value is used as the C<select>
3904 expression). Adds C<me.> onto the start of any column without a C<.> in
3905 it and sets C<select> from that, then auto-populates C<as> from
3906 C<select> as normal. (You may also use the C<cols> attribute, as in
3907 earlier versions of DBIC.)
3909 Essentially C<columns> does the same as L</select> and L</as>.
3911 columns => [ 'foo', { bar => 'baz' } ]
3915 select => [qw/foo baz/],
3922 =item Value: \@columns
3926 Indicates additional columns to be selected from storage. Works the same
3927 as L</columns> but adds columns to the selection. (You may also use the
3928 C<include_columns> attribute, as in earlier versions of DBIC). For
3931 $schema->resultset('CD')->search(undef, {
3932 '+columns' => ['artist.name'],
3936 would return all CDs and include a 'name' column to the information
3937 passed to object inflation. Note that the 'artist' is the name of the
3938 column (or relationship) accessor, and 'name' is the name of the column
3939 accessor in the related table.
3941 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3942 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3943 unary plus operator before it.
3945 =head2 include_columns
3949 =item Value: \@columns
3953 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3959 =item Value: \@select_columns
3963 Indicates which columns should be selected from the storage. You can use
3964 column names, or in the case of RDBMS back ends, function or stored procedure
3967 $rs = $schema->resultset('Employee')->search(undef, {
3970 { count => 'employeeid' },
3971 { max => { length => 'name' }, -as => 'longest_name' }
3976 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3978 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3979 use L</select>, to instruct DBIx::Class how to store the result of the column.
3980 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3981 identifier aliasing. You can however alias a function, so you can use it in
3982 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3983 attribute> supplied as shown in the example above.
3985 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3986 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3987 unary plus operator before it.
3993 Indicates additional columns to be selected from storage. Works the same as
3994 L</select> but adds columns to the default selection, instead of specifying
4003 =item Value: \@inflation_names
4007 Indicates column names for object inflation. That is L</as> indicates the
4008 slot name in which the column value will be stored within the
4009 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4010 identifier by the C<get_column> method (or via the object accessor B<if one
4011 with the same name already exists>) as shown below. The L</as> attribute has
4012 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4014 $rs = $schema->resultset('Employee')->search(undef, {
4017 { count => 'employeeid' },
4018 { max => { length => 'name' }, -as => 'longest_name' }
4027 If the object against which the search is performed already has an accessor
4028 matching a column name specified in C<as>, the value can be retrieved using
4029 the accessor as normal:
4031 my $name = $employee->name();
4033 If on the other hand an accessor does not exist in the object, you need to
4034 use C<get_column> instead:
4036 my $employee_count = $employee->get_column('employee_count');
4038 You can create your own accessors if required - see
4039 L<DBIx::Class::Manual::Cookbook> for details.
4045 Indicates additional column names for those added via L</+select>. See L</as>.
4053 =item Value: ($rel_name | \@rel_names | \%rel_names)
4057 Contains a list of relationships that should be joined for this query. For
4060 # Get CDs by Nine Inch Nails
4061 my $rs = $schema->resultset('CD')->search(
4062 { 'artist.name' => 'Nine Inch Nails' },
4063 { join => 'artist' }
4066 Can also contain a hash reference to refer to the other relation's relations.
4069 package MyApp::Schema::Track;
4070 use base qw/DBIx::Class/;
4071 __PACKAGE__->table('track');
4072 __PACKAGE__->add_columns(qw/trackid cd position title/);
4073 __PACKAGE__->set_primary_key('trackid');
4074 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4077 # In your application
4078 my $rs = $schema->resultset('Artist')->search(
4079 { 'track.title' => 'Teardrop' },
4081 join => { cd => 'track' },
4082 order_by => 'artist.name',
4086 You need to use the relationship (not the table) name in conditions,
4087 because they are aliased as such. The current table is aliased as "me", so
4088 you need to use me.column_name in order to avoid ambiguity. For example:
4090 # Get CDs from 1984 with a 'Foo' track
4091 my $rs = $schema->resultset('CD')->search(
4094 'tracks.name' => 'Foo'
4096 { join => 'tracks' }
4099 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4100 similarly for a third time). For e.g.
4102 my $rs = $schema->resultset('Artist')->search({
4103 'cds.title' => 'Down to Earth',
4104 'cds_2.title' => 'Popular',
4106 join => [ qw/cds cds/ ],
4109 will return a set of all artists that have both a cd with title 'Down
4110 to Earth' and a cd with title 'Popular'.
4112 If you want to fetch related objects from other tables as well, see L</prefetch>
4115 NOTE: An internal join-chain pruner will discard certain joins while
4116 constructing the actual SQL query, as long as the joins in question do not
4117 affect the retrieved result. This for example includes 1:1 left joins
4118 that are not part of the restriction specification (WHERE/HAVING) nor are
4119 a part of the query selection.
4121 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4127 =item Value: (0 | 1)
4131 When set to a true value, indicates that any rows fetched from joined has_many
4132 relationships are to be aggregated into the corresponding "parent" object. For
4133 example, the resultset:
4135 my $rs = $schema->resultset('CD')->search({}, {
4136 '+columns' => [ qw/ tracks.title tracks.position / ],
4141 While executing the following query:
4143 SELECT me.*, tracks.title, tracks.position
4145 LEFT JOIN track tracks
4146 ON tracks.cdid = me.cdid
4148 Will return only as many objects as there are rows in the CD source, even
4149 though the result of the query may span many rows. Each of these CD objects
4150 will in turn have multiple "Track" objects hidden behind the has_many
4151 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4152 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4153 product"), with each CD object containing exactly one of all fetched Track data.
4155 When a collapse is requested on a non-ordered resultset, an order by some
4156 unique part of the main source (the left-most table) is inserted automatically.
4157 This is done so that the resultset is allowed to be "lazy" - calling
4158 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4159 object with all of its related data.
4161 If an L</order_by> is already declared, and orders the resultset in a way that
4162 makes collapsing as described above impossible (e.g. C<< ORDER BY
4163 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4164 switch to "eager" mode and slurp the entire resultset before consturcting the
4165 first object returned by L</next>.
4167 Setting this attribute on a resultset that does not join any has_many
4168 relations is a no-op.
4170 For a more in-depth discussion, see L</PREFETCHING>.
4176 =item Value: ($rel_name | \@rel_names | \%rel_names)
4180 This attribute is a shorthand for specifying a L</join> spec, adding all
4181 columns from the joined related sources as L</+columns> and setting
4182 L</collapse> to a true value. For example, the following two queries are
4185 my $rs = $schema->resultset('Artist')->search({}, {
4186 prefetch => { cds => ['genre', 'tracks' ] },
4191 my $rs = $schema->resultset('Artist')->search({}, {
4192 join => { cds => ['genre', 'tracks' ] },
4196 { +{ "cds.$_" => "cds.$_" } }
4197 $schema->source('Artist')->related_source('cds')->columns
4200 { +{ "cds.genre.$_" => "genre.$_" } }
4201 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4204 { +{ "cds.tracks.$_" => "tracks.$_" } }
4205 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4210 Both producing the following SQL:
4212 SELECT me.artistid, me.name, me.rank, me.charfield,
4213 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4214 genre.genreid, genre.name,
4215 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4218 ON cds.artist = me.artistid
4219 LEFT JOIN genre genre
4220 ON genre.genreid = cds.genreid
4221 LEFT JOIN track tracks
4222 ON tracks.cd = cds.cdid
4223 ORDER BY me.artistid
4225 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4226 the arguments are properly merged and generally do the right thing. For
4227 example, you may want to do the following:
4229 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4230 { 'genre.genreid' => undef },
4232 join => { cds => 'genre' },
4237 Which generates the following SQL:
4239 SELECT me.artistid, me.name, me.rank, me.charfield,
4240 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4243 ON cds.artist = me.artistid
4244 LEFT JOIN genre genre
4245 ON genre.genreid = cds.genreid
4246 WHERE genre.genreid IS NULL
4247 ORDER BY me.artistid
4249 For a more in-depth discussion, see L</PREFETCHING>.
4255 =item Value: $source_alias
4259 Sets the source alias for the query. Normally, this defaults to C<me>, but
4260 nested search queries (sub-SELECTs) might need specific aliases set to
4261 reference inner queries. For example:
4264 ->related_resultset('CDs')
4265 ->related_resultset('Tracks')
4267 'track.id' => { -ident => 'none_search.id' },
4271 my $ids = $self->search({
4274 alias => 'none_search',
4275 group_by => 'none_search.id',
4276 })->get_column('id')->as_query;
4278 $self->search({ id => { -in => $ids } })
4280 This attribute is directly tied to L</current_source_alias>.
4290 Makes the resultset paged and specifies the page to retrieve. Effectively
4291 identical to creating a non-pages resultset and then calling ->page($page)
4294 If L</rows> attribute is not specified it defaults to 10 rows per page.
4296 When you have a paged resultset, L</count> will only return the number
4297 of rows in the page. To get the total, use the L</pager> and call
4298 C<total_entries> on it.
4308 Specifies the maximum number of rows for direct retrieval or the number of
4309 rows per page if the page attribute or method is used.
4315 =item Value: $offset
4319 Specifies the (zero-based) row number for the first row to be returned, or the
4320 of the first row of the first page if paging is used.
4322 =head2 software_limit
4326 =item Value: (0 | 1)
4330 When combined with L</rows> and/or L</offset> the generated SQL will not
4331 include any limit dialect stanzas. Instead the entire result will be selected
4332 as if no limits were specified, and DBIC will perform the limit locally, by
4333 artificially advancing and finishing the resulting L</cursor>.
4335 This is the recommended way of performing resultset limiting when no sane RDBMS
4336 implementation is available (e.g.
4337 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4338 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4344 =item Value: \@columns
4348 A arrayref of columns to group by. Can include columns of joined tables.
4350 group_by => [qw/ column1 column2 ... /]
4356 =item Value: $condition
4360 HAVING is a select statement attribute that is applied between GROUP BY and
4361 ORDER BY. It is applied to the after the grouping calculations have been
4364 having => { 'count_employee' => { '>=', 100 } }
4366 or with an in-place function in which case literal SQL is required:
4368 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4374 =item Value: (0 | 1)
4378 Set to 1 to group by all columns. If the resultset already has a group_by
4379 attribute, this setting is ignored and an appropriate warning is issued.
4385 Adds to the WHERE clause.
4387 # only return rows WHERE deleted IS NULL for all searches
4388 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4390 Can be overridden by passing C<< { where => undef } >> as an attribute
4393 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4399 Set to 1 to cache search results. This prevents extra SQL queries if you
4400 revisit rows in your ResultSet:
4402 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4404 while( my $artist = $resultset->next ) {
4408 $rs->first; # without cache, this would issue a query
4410 By default, searches are not cached.
4412 For more examples of using these attributes, see
4413 L<DBIx::Class::Manual::Cookbook>.
4419 =item Value: ( 'update' | 'shared' | \$scalar )
4423 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4424 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4429 DBIx::Class supports arbitrary related data prefetching from multiple related
4430 sources. Any combination of relationship types and column sets are supported.
4431 If L<collapsing|/collapse> is requested, there is an additional requirement of
4432 selecting enough data to make every individual object uniquely identifiable.
4434 Here are some more involved examples, based on the following relationship map:
4437 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4438 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4439 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4441 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4443 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4447 my $rs = $schema->resultset('Tag')->search(
4456 The initial search results in SQL like the following:
4458 SELECT tag.*, cd.*, artist.* FROM tag
4459 JOIN cd ON tag.cd = cd.cdid
4460 JOIN artist ON cd.artist = artist.artistid
4462 L<DBIx::Class> has no need to go back to the database when we access the
4463 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4466 Simple prefetches will be joined automatically, so there is no need
4467 for a C<join> attribute in the above search.
4469 The L</prefetch> attribute can be used with any of the relationship types
4470 and multiple prefetches can be specified together. Below is a more complex
4471 example that prefetches a CD's artist, its liner notes (if present),
4472 the cover image, the tracks on that CD, and the guests on those
4475 my $rs = $schema->resultset('CD')->search(
4479 { artist => 'record_label'}, # belongs_to => belongs_to
4480 'liner_note', # might_have
4481 'cover_image', # has_one
4482 { tracks => 'guests' }, # has_many => has_many
4487 This will produce SQL like the following:
4489 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4493 ON artist.artistid = me.artistid
4494 JOIN record_label record_label
4495 ON record_label.labelid = artist.labelid
4496 LEFT JOIN track tracks
4497 ON tracks.cdid = me.cdid
4498 LEFT JOIN guest guests
4499 ON guests.trackid = track.trackid
4500 LEFT JOIN liner_notes liner_note
4501 ON liner_note.cdid = me.cdid
4502 JOIN cd_artwork cover_image
4503 ON cover_image.cdid = me.cdid
4506 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4507 C<tracks>, and C<guests> of the CD will all be available through the
4508 relationship accessors without the need for additional queries to the
4513 Prefetch does a lot of deep magic. As such, it may not behave exactly
4514 as you might expect.
4520 Prefetch uses the L</cache> to populate the prefetched relationships. This
4521 may or may not be what you want.
4525 If you specify a condition on a prefetched relationship, ONLY those
4526 rows that match the prefetched condition will be fetched into that relationship.
4527 This means that adding prefetch to a search() B<may alter> what is returned by
4528 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4530 my $artist_rs = $schema->resultset('Artist')->search({
4536 my $count = $artist_rs->first->cds->count;
4538 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4540 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4542 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4544 That cmp_ok() may or may not pass depending on the datasets involved. In other
4545 words the C<WHERE> condition would apply to the entire dataset, just like
4546 it would in regular SQL. If you want to add a condition only to the "right side"
4547 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4548 condition|DBIx::Class::Relationship::Base/condition>
4552 =head1 DBIC BIND VALUES
4554 Because DBIC may need more information to bind values than just the column name
4555 and value itself, it uses a special format for both passing and receiving bind
4556 values. Each bind value should be composed of an arrayref of
4557 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4563 If present (in any form), this is what is being passed directly to bind_param.
4564 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4565 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4567 If this is specified, all other bind options described below are ignored.
4571 If present, this is used to infer the actual bind attribute by passing to
4572 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4573 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4575 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4576 currently drivers are expected to "Do the Right Thing" when given a common
4577 datatype name. (Not ideal, but that's what we got at this point.)
4581 Currently used to correctly allocate buffers for bind_param_inout().
4582 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4583 or to a sensible value based on the "data_type".
4587 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4588 explicitly specified they are never overriden). Also used by some weird DBDs,
4589 where the column name should be available at bind_param time (e.g. Oracle).
4593 For backwards compatibility and convenience, the following shortcuts are
4596 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4597 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4598 [ undef, $val ] === [ {}, $val ]
4600 =head1 AUTHOR AND CONTRIBUTORS
4602 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4606 You may distribute this code under the same terms as Perl itself.