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 $new_attrs->{cols}) {
446 carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
447 if ($new_attrs->{columns}) {
448 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
451 $new_attrs->{columns} = $c;
456 # join/prefetch use their own crazy merging heuristics
457 foreach my $key (qw/join prefetch/) {
458 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
459 if exists $call_attrs->{$key};
462 # stack binds together
463 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
467 for ($old_where, $call_cond) {
469 $new_attrs->{where} = $self->_stack_cond (
470 $_, $new_attrs->{where}
475 if (defined $old_having) {
476 $new_attrs->{having} = $self->_stack_cond (
477 $old_having, $new_attrs->{having}
481 my $rs = (ref $self)->new($rsrc, $new_attrs);
483 $rs->set_cache($cache) if ($cache);
489 sub _normalize_selection {
490 my ($self, $attrs) = @_;
493 if ( exists $attrs->{include_columns} ) {
494 carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
495 $attrs->{'+columns'} = $self->_merge_attr(
496 $attrs->{'+columns'}, delete $attrs->{include_columns}
500 # columns are always placed first, however
502 # Keep the X vs +X separation until _resolved_attrs time - this allows to
503 # delay the decision on whether to use a default select list ($rsrc->columns)
504 # allowing stuff like the remove_columns helper to work
506 # select/as +select/+as pairs need special handling - the amount of select/as
507 # elements in each pair does *not* have to be equal (think multicolumn
508 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
509 # supplied at all) - try to infer the alias, either from the -as parameter
510 # of the selector spec, or use the parameter whole if it looks like a column
511 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
512 # is ok as well), but make sure no more additions to the 'as' chain take place
513 for my $pref ('', '+') {
515 my ($sel, $as) = map {
516 my $key = "${pref}${_}";
518 my $val = [ ref $attrs->{$key} eq 'ARRAY'
520 : $attrs->{$key} || ()
522 delete $attrs->{$key};
526 if (! @$as and ! @$sel ) {
529 elsif (@$as and ! @$sel) {
530 $self->throw_exception(
531 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
535 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
536 # if any @$as has been supplied we assume the user knows what (s)he is doing
537 # and blindly keep stacking up pieces
538 unless ($attrs->{_dark_selector}) {
541 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
542 push @$as, $_->{-as};
544 # assume any plain no-space, no-parenthesis string to be a column spec
545 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
546 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
549 # if all else fails - raise a flag that no more aliasing will be allowed
551 $attrs->{_dark_selector} = {
553 string => ($dark_sel_dumper ||= do {
554 require Data::Dumper::Concise;
555 Data::Dumper::Concise::DumperObject()->Indent(0);
556 })->Values([$_])->Dump
564 elsif (@$as < @$sel) {
565 $self->throw_exception(
566 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
569 elsif ($pref and $attrs->{_dark_selector}) {
570 $self->throw_exception(
571 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
577 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
578 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
583 my ($self, $left, $right) = @_;
585 # collapse single element top-level conditions
586 # (single pass only, unlikely to need recursion)
587 for ($left, $right) {
588 if (ref $_ eq 'ARRAY') {
596 elsif (ref $_ eq 'HASH') {
597 my ($first, $more) = keys %$_;
600 if (! defined $first) {
604 elsif (! defined $more) {
605 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
608 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
615 # merge hashes with weeding out of duplicates (simple cases only)
616 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
618 # shallow copy to destroy
619 $right = { %$right };
620 for (grep { exists $right->{$_} } keys %$left) {
621 # the use of eq_deeply here is justified - the rhs of an
622 # expression can contain a lot of twisted weird stuff
623 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
626 $right = undef unless keys %$right;
630 if (defined $left xor defined $right) {
631 return defined $left ? $left : $right;
633 elsif (! defined $left) {
637 return { -and => [ $left, $right ] };
641 =head2 search_literal
643 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
644 should only be used in that context. C<search_literal> is a convenience
645 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
646 want to ensure columns are bound correctly, use L</search>.
648 See L<DBIx::Class::Manual::Cookbook/Searching> and
649 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
650 require C<search_literal>.
654 =item Arguments: $sql_fragment, @standalone_bind_values
656 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
660 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
661 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
663 Pass a literal chunk of SQL to be added to the conditional part of the
666 Example of how to use C<search> instead of C<search_literal>
668 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
669 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
674 my ($self, $sql, @bind) = @_;
676 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
679 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
686 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
688 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
692 Finds and returns a single row based on supplied criteria. Takes either a
693 hashref with the same format as L</create> (including inference of foreign
694 keys from related objects), or a list of primary key values in the same
695 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
696 declaration on the L</result_source>.
698 In either case an attempt is made to combine conditions already existing on
699 the resultset with the condition passed to this method.
701 To aid with preparing the correct query for the storage you may supply the
702 C<key> attribute, which is the name of a
703 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
704 unique constraint corresponding to the
705 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
706 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
707 to construct a query that satisfies the named unique constraint fully (
708 non-NULL values for each column member of the constraint) an exception is
711 If no C<key> is specified, the search is carried over all unique constraints
712 which are fully defined by the available condition.
714 If no such constraint is found, C<find> currently defaults to a simple
715 C<< search->(\%column_values) >> which may or may not do what you expect.
716 Note that this fallback behavior may be deprecated in further versions. If
717 you need to search with arbitrary conditions - use L</search>. If the query
718 resulting from this fallback produces more than one row, a warning to the
719 effect is issued, though only the first row is constructed and returned as
722 In addition to C<key>, L</find> recognizes and applies standard
723 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
725 Note that if you have extra concerns about the correctness of the resulting
726 query you need to specify the C<key> attribute and supply the entire condition
727 as an argument to find (since it is not always possible to perform the
728 combination of the resultset condition with the supplied one, especially if
729 the resultset condition contains literal sql).
731 For example, to find a row by its primary key:
733 my $cd = $schema->resultset('CD')->find(5);
735 You can also find a row by a specific unique constraint:
737 my $cd = $schema->resultset('CD')->find(
739 artist => 'Massive Attack',
740 title => 'Mezzanine',
742 { key => 'cd_artist_title' }
745 See also L</find_or_create> and L</update_or_create>.
751 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
753 my $rsrc = $self->result_source;
756 if (exists $attrs->{key}) {
757 $constraint_name = defined $attrs->{key}
759 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
763 # Parse out the condition from input
766 if (ref $_[0] eq 'HASH') {
767 $call_cond = { %{$_[0]} };
770 # if only values are supplied we need to default to 'primary'
771 $constraint_name = 'primary' unless defined $constraint_name;
773 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
775 $self->throw_exception(
776 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
779 $self->throw_exception (
780 'find() expects either a column/value hashref, or a list of values '
781 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
782 ) unless @c_cols == @_;
785 @{$call_cond}{@c_cols} = @_;
789 for my $key (keys %$call_cond) {
791 my $keyref = ref($call_cond->{$key})
793 my $relinfo = $rsrc->relationship_info($key)
795 my $val = delete $call_cond->{$key};
797 next if $keyref eq 'ARRAY'; # has_many for multi_create
799 my $rel_q = $rsrc->_resolve_condition(
800 $relinfo->{cond}, $val, $key, $key
802 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
803 @related{keys %$rel_q} = values %$rel_q;
807 # relationship conditions take precedence (?)
808 @{$call_cond}{keys %related} = values %related;
810 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
812 if (defined $constraint_name) {
813 $final_cond = $self->_qualify_cond_columns (
815 $self->_build_unique_cond (
823 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
824 # This means that we got here after a merger of relationship conditions
825 # in ::Relationship::Base::search_related (the row method), and furthermore
826 # the relationship is of the 'single' type. This means that the condition
827 # provided by the relationship (already attached to $self) is sufficient,
828 # as there can be only one row in the database that would satisfy the
832 # no key was specified - fall down to heuristics mode:
833 # run through all unique queries registered on the resultset, and
834 # 'OR' all qualifying queries together
835 my (@unique_queries, %seen_column_combinations);
836 for my $c_name ($rsrc->unique_constraint_names) {
837 next if $seen_column_combinations{
838 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
841 push @unique_queries, try {
842 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
846 $final_cond = @unique_queries
847 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
848 : $self->_non_unique_find_fallback ($call_cond, $attrs)
852 # Run the query, passing the result_class since it should propagate for find
853 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
854 if ($rs->_resolved_attrs->{collapse}) {
856 carp "Query returned more than one row" if $rs->next;
864 # This is a stop-gap method as agreed during the discussion on find() cleanup:
865 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
867 # It is invoked when find() is called in legacy-mode with insufficiently-unique
868 # condition. It is provided for overrides until a saner way forward is devised
870 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
871 # the road. Please adjust your tests accordingly to catch this situation early
872 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
874 # The method will not be removed without an adequately complete replacement
875 # for strict-mode enforcement
876 sub _non_unique_find_fallback {
877 my ($self, $cond, $attrs) = @_;
879 return $self->_qualify_cond_columns(
881 exists $attrs->{alias}
883 : $self->{attrs}{alias}
888 sub _qualify_cond_columns {
889 my ($self, $cond, $alias) = @_;
891 my %aliased = %$cond;
892 for (keys %aliased) {
893 $aliased{"$alias.$_"} = delete $aliased{$_}
900 sub _build_unique_cond {
901 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
903 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
905 # combination may fail if $self->{cond} is non-trivial
906 my ($final_cond) = try {
907 $self->_merge_with_rscond ($extra_cond)
912 # trim out everything not in $columns
913 $final_cond = { map {
914 exists $final_cond->{$_}
915 ? ( $_ => $final_cond->{$_} )
919 if (my @missing = grep
920 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
923 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
925 join (', ', map { "'$_'" } @missing),
932 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
934 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
936 carp_unique ( sprintf (
937 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
938 . 'values in column(s): %s). This is almost certainly not what you wanted, '
939 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
941 join (', ', map { "'$_'" } @undefs),
948 =head2 search_related
952 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
954 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
958 $new_rs = $cd_rs->search_related('artist', {
962 Searches the specified relationship, optionally specifying a condition and
963 attributes for matching records. See L</ATTRIBUTES> for more information.
965 In list context, C<< ->all() >> is called implicitly on the resultset, thus
966 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
968 See also L</search_related_rs>.
973 return shift->related_resultset(shift)->search(@_);
976 =head2 search_related_rs
978 This method works exactly the same as search_related, except that
979 it guarantees a resultset, even in list context.
983 sub search_related_rs {
984 return shift->related_resultset(shift)->search_rs(@_);
991 =item Arguments: none
993 =item Return Value: L<$cursor|DBIx::Class::Cursor>
997 Returns a storage-driven cursor to the given resultset. See
998 L<DBIx::Class::Cursor> for more information.
1005 return $self->{cursor} ||= do {
1006 my $attrs = { %{$self->_resolved_attrs } };
1007 $self->result_source->storage->select(
1008 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1017 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1019 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1023 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1025 Inflates the first result without creating a cursor if the resultset has
1026 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1029 While this method can take an optional search condition (just like L</search>)
1030 being a fast-code-path it does not recognize search attributes. If you need to
1031 add extra joins or similar, call L</search> and then chain-call L</single> on the
1032 L<DBIx::Class::ResultSet> returned.
1038 As of 0.08100, this method enforces the assumption that the preceding
1039 query returns only one row. If more than one row is returned, you will receive
1042 Query returned more than one row
1044 In this case, you should be using L</next> or L</find> instead, or if you really
1045 know what you are doing, use the L</rows> attribute to explicitly limit the size
1048 This method will also throw an exception if it is called on a resultset prefetching
1049 has_many, as such a prefetch implies fetching multiple rows from the database in
1050 order to assemble the resulting object.
1057 my ($self, $where) = @_;
1059 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1062 my $attrs = { %{$self->_resolved_attrs} };
1064 $self->throw_exception(
1065 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
1066 ) if $attrs->{collapse};
1069 if (defined $attrs->{where}) {
1072 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1073 $where, delete $attrs->{where} ]
1076 $attrs->{where} = $where;
1080 my $data = [ $self->result_source->storage->select_single(
1081 $attrs->{from}, $attrs->{select},
1082 $attrs->{where}, $attrs
1084 return undef unless @$data;
1085 $self->{_stashed_rows} = [ $data ];
1086 $self->_construct_results->[0];
1092 # Recursively collapse the query, accumulating values for each column.
1094 sub _collapse_query {
1095 my ($self, $query, $collapsed) = @_;
1099 if (ref $query eq 'ARRAY') {
1100 foreach my $subquery (@$query) {
1101 next unless ref $subquery; # -or
1102 $collapsed = $self->_collapse_query($subquery, $collapsed);
1105 elsif (ref $query eq 'HASH') {
1106 if (keys %$query and (keys %$query)[0] eq '-and') {
1107 foreach my $subquery (@{$query->{-and}}) {
1108 $collapsed = $self->_collapse_query($subquery, $collapsed);
1112 foreach my $col (keys %$query) {
1113 my $value = $query->{$col};
1114 $collapsed->{$col}{$value}++;
1126 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1128 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1132 my $max_length = $rs->get_column('length')->max;
1134 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1139 my ($self, $column) = @_;
1140 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1148 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1150 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1154 # WHERE title LIKE '%blue%'
1155 $cd_rs = $rs->search_like({ title => '%blue%'});
1157 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1158 that this is simply a convenience method retained for ex Class::DBI users.
1159 You most likely want to use L</search> with specific operators.
1161 For more information, see L<DBIx::Class::Manual::Cookbook>.
1163 This method is deprecated and will be removed in 0.09. Use L</search()>
1164 instead. An example conversion is:
1166 ->search_like({ foo => 'bar' });
1170 ->search({ foo => { like => 'bar' } });
1177 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1178 .' Instead use ->search({ x => { -like => "y%" } })'
1179 .' (note the outer pair of {}s - they are important!)'
1181 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1182 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1183 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1184 return $class->search($query, { %$attrs });
1191 =item Arguments: $first, $last
1193 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1197 Returns a resultset or object list representing a subset of elements from the
1198 resultset slice is called on. Indexes are from 0, i.e., to get the first
1199 three records, call:
1201 my ($one, $two, $three) = $rs->slice(0, 2);
1206 my ($self, $min, $max) = @_;
1207 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1208 $attrs->{offset} = $self->{attrs}{offset} || 0;
1209 $attrs->{offset} += $min;
1210 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1211 return $self->search(undef, $attrs);
1212 #my $slice = (ref $self)->new($self->result_source, $attrs);
1213 #return (wantarray ? $slice->all : $slice);
1220 =item Arguments: none
1222 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1226 Returns the next element in the resultset (C<undef> is there is none).
1228 Can be used to efficiently iterate over records in the resultset:
1230 my $rs = $schema->resultset('CD')->search;
1231 while (my $cd = $rs->next) {
1235 Note that you need to store the resultset object, and call C<next> on it.
1236 Calling C<< resultset('Table')->next >> repeatedly will always return the
1237 first record from the resultset.
1244 if (my $cache = $self->get_cache) {
1245 $self->{all_cache_position} ||= 0;
1246 return $cache->[$self->{all_cache_position}++];
1249 if ($self->{attrs}{cache}) {
1250 delete $self->{pager};
1251 $self->{all_cache_position} = 1;
1252 return ($self->all)[0];
1255 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1257 $self->{_stashed_results} = $self->_construct_results
1260 return shift @{$self->{_stashed_results}};
1263 # Constructs as many results as it can in one pass while respecting
1264 # cursor laziness. Several modes of operation:
1266 # * Always builds everything present in @{$self->{_stashed_rows}}
1267 # * If called with $fetch_all true - pulls everything off the cursor and
1268 # builds all result structures (or objects) in one pass
1269 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1270 # and if the resultset is ordered properly by the left side:
1271 # * Fetches stuff off the cursor until the "master object" changes,
1272 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1274 # * Just fetches, and collapses/constructs everything as if $fetch_all
1275 # was requested (there is no other way to collapse except for an
1277 # * If no collapse is requested - just get the next row, construct and
1279 sub _construct_results {
1280 my ($self, $fetch_all) = @_;
1282 my $rsrc = $self->result_source;
1283 my $attrs = $self->_resolved_attrs;
1288 ! $attrs->{order_by}
1292 my @pcols = $rsrc->primary_columns
1294 # default order for collapsing unless the user asked for something
1295 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
1296 $attrs->{_ordered_for_collapse} = 1;
1297 $attrs->{_order_is_artificial} = 1;
1300 my $cursor = $self->cursor;
1302 # this will be used as both initial raw-row collector AND as a RV of
1303 # _construct_results. Not regrowing the array twice matters a lot...
1304 # a surprising amount actually
1305 my $rows = delete $self->{_stashed_rows};
1307 my $did_fetch_all = $fetch_all;
1310 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1311 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1313 elsif( $attrs->{collapse} ) {
1315 $attrs->{_ordered_for_collapse} = (
1321 ->_main_source_order_by_portion_is_stable($rsrc, $attrs->{order_by}, $attrs->{where})
1323 ) unless defined $attrs->{_ordered_for_collapse};
1325 if (! $attrs->{_ordered_for_collapse}) {
1328 # instead of looping over ->next, use ->all in stealth mode
1329 # *without* calling a ->reset afterwards
1330 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1331 if (! $cursor->{_done}) {
1332 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1333 $cursor->{_done} = 1;
1338 if (! $did_fetch_all and ! @{$rows||[]} ) {
1339 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1340 if (scalar (my @r = $cursor->next) ) {
1345 return undef unless @{$rows||[]};
1347 my @extra_collapser_args;
1348 if ($attrs->{collapse} and ! $did_fetch_all ) {
1350 @extra_collapser_args = (
1351 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1352 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1353 ($self->{_stashed_rows} = []), # where does it stuff excess
1357 # hotspot - skip the setter
1358 my $res_class = $self->_result_class;
1360 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1361 $res_class->can ('inflate_result')
1362 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1365 my $infmap = $attrs->{as};
1368 $self->{_result_inflator}{is_core_row} = ( (
1371 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1372 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1374 $self->{_result_inflator}{is_hri} = ( (
1375 ! $self->{_result_inflator}{is_core_row}
1378 require DBIx::Class::ResultClass::HashRefInflator
1380 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1382 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1385 if (! $attrs->{_related_results_construction}) {
1386 # construct a much simpler array->hash folder for the one-table cases right here
1387 if ($self->{_result_inflator}{is_hri}) {
1388 for my $r (@$rows) {
1389 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1392 # FIXME SUBOPTIMAL this is a very very very hot spot
1393 # while rather optimal we can *still* do much better, by
1394 # building a smarter Row::inflate_result(), and
1395 # switch to feeding it data via a much leaner interface
1397 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1398 # this particular resultset size
1399 elsif (@$rows < 60) {
1400 for my $r (@$rows) {
1401 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1406 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1407 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1411 # Special-case multi-object HRI (we always prune, and there is no $inflator_cref pass)
1412 elsif ($self->{_result_inflator}{is_hri}) {
1413 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1415 inflate_map => $infmap,
1416 selection => $attrs->{select},
1417 collapse => $attrs->{collapse},
1418 premultiplied => $attrs->{_main_source_premultiplied},
1420 prune_null_branches => 1,
1421 }) )->($rows, @extra_collapser_args);
1423 # Regular multi-object
1425 my $parser_type = $self->{_result_inflator}{is_core_row} ? 'classic_pruning' : 'classic_nonpruning';
1427 ( $self->{_row_parser}{$parser_type} ||= $rsrc->_mk_row_parser({
1429 inflate_map => $infmap,
1430 selection => $attrs->{select},
1431 collapse => $attrs->{collapse},
1432 premultiplied => $attrs->{_main_source_premultiplied},
1433 prune_null_branches => $self->{_result_inflator}{is_core_row},
1434 }) )->($rows, @extra_collapser_args);
1436 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1439 # The @$rows check seems odd at first - why wouldn't we want to warn
1440 # regardless? The issue is things like find() etc, where the user
1441 # *knows* only one result will come back. In these cases the ->all
1442 # is not a pessimization, but rather something we actually want
1444 'Unable to properly collapse has_many results in iterator mode due '
1445 . 'to order criteria - performed an eager cursor slurp underneath. '
1446 . 'Consider using ->all() instead'
1447 ) if ( ! $fetch_all and @$rows > 1 );
1452 =head2 result_source
1456 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1458 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1462 An accessor for the primary ResultSource object from which this ResultSet
1469 =item Arguments: $result_class?
1471 =item Return Value: $result_class
1475 An accessor for the class to use when creating result objects. Defaults to
1476 C<< result_source->result_class >> - which in most cases is the name of the
1477 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1479 Note that changing the result_class will also remove any components
1480 that were originally loaded in the source class via
1481 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1482 in the original source class will not run.
1487 my ($self, $result_class) = @_;
1488 if ($result_class) {
1490 # don't fire this for an object
1491 $self->ensure_class_loaded($result_class)
1492 unless ref($result_class);
1494 if ($self->get_cache) {
1495 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1497 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1498 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1499 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1502 $self->_result_class($result_class);
1504 delete $self->{_result_inflator};
1506 $self->_result_class;
1513 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1515 =item Return Value: $count
1519 Performs an SQL C<COUNT> with the same query as the resultset was built
1520 with to find the number of elements. Passing arguments is equivalent to
1521 C<< $rs->search ($cond, \%attrs)->count >>
1527 return $self->search(@_)->count if @_ and defined $_[0];
1528 return scalar @{ $self->get_cache } if $self->get_cache;
1530 my $attrs = { %{ $self->_resolved_attrs } };
1532 # this is a little optimization - it is faster to do the limit
1533 # adjustments in software, instead of a subquery
1534 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1537 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1538 $crs = $self->_count_subq_rs ($attrs);
1541 $crs = $self->_count_rs ($attrs);
1543 my $count = $crs->next;
1545 $count -= $offset if $offset;
1546 $count = $rows if $rows and $rows < $count;
1547 $count = 0 if ($count < 0);
1556 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1558 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1562 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1563 This can be very handy for subqueries:
1565 ->search( { amount => $some_rs->count_rs->as_query } )
1567 As with regular resultsets the SQL query will be executed only after
1568 the resultset is accessed via L</next> or L</all>. That would return
1569 the same single value obtainable via L</count>.
1575 return $self->search(@_)->count_rs if @_;
1577 # this may look like a lack of abstraction (count() does about the same)
1578 # but in fact an _rs *must* use a subquery for the limits, as the
1579 # software based limiting can not be ported if this $rs is to be used
1580 # in a subquery itself (i.e. ->as_query)
1581 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1582 return $self->_count_subq_rs;
1585 return $self->_count_rs;
1590 # returns a ResultSetColumn object tied to the count query
1593 my ($self, $attrs) = @_;
1595 my $rsrc = $self->result_source;
1596 $attrs ||= $self->_resolved_attrs;
1598 my $tmp_attrs = { %$attrs };
1599 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1600 delete @{$tmp_attrs}{qw/rows offset order_by _related_results_construction record_filter for/};
1602 # overwrite the selector (supplied by the storage)
1603 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1604 $tmp_attrs->{as} = 'count';
1606 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1612 # same as above but uses a subquery
1614 sub _count_subq_rs {
1615 my ($self, $attrs) = @_;
1617 my $rsrc = $self->result_source;
1618 $attrs ||= $self->_resolved_attrs;
1620 my $sub_attrs = { %$attrs };
1621 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1622 delete @{$sub_attrs}{qw/collapse columns as select _related_results_construction order_by for/};
1624 # if we multi-prefetch we group_by something unique, as this is what we would
1625 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1626 if ( $attrs->{collapse} ) {
1627 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1628 $rsrc->_identifying_column_set || $self->throw_exception(
1629 'Unable to construct a unique group_by criteria properly collapsing the '
1630 . 'has_many prefetch before count()'
1635 # Calculate subquery selector
1636 if (my $g = $sub_attrs->{group_by}) {
1638 my $sql_maker = $rsrc->storage->sql_maker;
1640 # necessary as the group_by may refer to aliased functions
1642 for my $sel (@{$attrs->{select}}) {
1643 $sel_index->{$sel->{-as}} = $sel
1644 if (ref $sel eq 'HASH' and $sel->{-as});
1647 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1648 # also look for named aggregates referred in the having clause
1649 # having often contains scalarrefs - thus parse it out entirely
1651 if ($attrs->{having}) {
1652 local $sql_maker->{having_bind};
1653 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1654 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1655 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1656 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1657 # if we don't unset it we screw up retarded but unfortunately working
1658 # 'MAX(foo.bar)' => { '>', 3 }
1659 $sql_maker->{name_sep} = '';
1662 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1664 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1667 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1668 # and if all fails for an utterly naive quoted scalar-with-function
1669 while ($having_sql =~ /
1670 $rquote $sep $lquote (.+?) $rquote
1672 [\s,] \w+ \. (\w+) [\s,]
1674 [\s,] $lquote (.+?) $rquote [\s,]
1676 my $part = $1 || $2 || $3; # one of them matched if we got here
1677 unless ($seen_having{$part}++) {
1684 my $colpiece = $sel_index->{$_} || $_;
1686 # unqualify join-based group_by's. Arcane but possible query
1687 # also horrible horrible hack to alias a column (not a func.)
1688 # (probably need to introduce SQLA syntax)
1689 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1692 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1694 push @{$sub_attrs->{select}}, $colpiece;
1698 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1699 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1702 return $rsrc->resultset_class
1703 ->new ($rsrc, $sub_attrs)
1705 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1706 ->get_column ('count');
1710 =head2 count_literal
1712 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1713 should only be used in that context. See L</search_literal> for further info.
1717 =item Arguments: $sql_fragment, @standalone_bind_values
1719 =item Return Value: $count
1723 Counts the results in a literal query. Equivalent to calling L</search_literal>
1724 with the passed arguments, then L</count>.
1728 sub count_literal { shift->search_literal(@_)->count; }
1734 =item Arguments: none
1736 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1740 Returns all elements in the resultset.
1747 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1750 delete @{$self}{qw/_stashed_rows _stashed_results/};
1752 if (my $c = $self->get_cache) {
1756 $self->cursor->reset;
1758 my $objs = $self->_construct_results('fetch_all') || [];
1760 $self->set_cache($objs) if $self->{attrs}{cache};
1769 =item Arguments: none
1771 =item Return Value: $self
1775 Resets the resultset's cursor, so you can iterate through the elements again.
1776 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1784 delete @{$self}{qw/_stashed_rows _stashed_results/};
1785 $self->{all_cache_position} = 0;
1786 $self->cursor->reset;
1794 =item Arguments: none
1796 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1800 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1801 an object for the first result (or C<undef> if the resultset is empty).
1806 return $_[0]->reset->next;
1812 # Determines whether and what type of subquery is required for the $rs operation.
1813 # If grouping is necessary either supplies its own, or verifies the current one
1814 # After all is done delegates to the proper storage method.
1816 sub _rs_update_delete {
1817 my ($self, $op, $values) = @_;
1819 my $rsrc = $self->result_source;
1820 my $storage = $rsrc->schema->storage;
1822 my $attrs = { %{$self->_resolved_attrs} };
1824 my $join_classifications;
1825 my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
1827 # do we need a subquery for any reason?
1829 defined $existing_group_by
1831 # if {from} is unparseable wrap a subq
1832 ref($attrs->{from}) ne 'ARRAY'
1834 # limits call for a subq
1835 $self->_has_resolved_attr(qw/rows offset/)
1838 # simplify the joinmap, so we can further decide if a subq is necessary
1839 if (!$needs_subq and @{$attrs->{from}} > 1) {
1840 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1842 # check if there are any joins left after the prune
1843 if ( @{$attrs->{from}} > 1 ) {
1844 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1845 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1851 # any non-pruneable joins imply subq
1852 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1856 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1858 (ref $attrs->{from}[0]) ne 'HASH'
1860 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1864 # do we need anything like a subquery?
1865 if (! $needs_subq) {
1866 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1867 # a condition containing 'me' or other table prefixes will not work
1868 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1870 my $sqla = $rsrc->storage->sql_maker;
1871 local $sqla->{_dequalify_idents} = 1;
1872 \[ $sqla->_recurse_where($self->{cond}) ];
1876 # we got this far - means it is time to wrap a subquery
1877 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1879 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1885 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1886 delete $attrs->{$_} for qw/select as collapse _related_results_construction/;
1887 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1889 # this will be consumed by the pruner waaaaay down the stack
1890 $attrs->{_force_prune_multiplying_joins} = 1;
1892 my $subrs = (ref $self)->new($rsrc, $attrs);
1894 if (@$idcols == 1) {
1895 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1897 elsif ($storage->_use_multicolumn_in) {
1898 # no syntax for calling this properly yet
1899 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1900 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1901 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1906 # if all else fails - get all primary keys and operate over a ORed set
1907 # wrap in a transaction for consistency
1908 # this is where the group_by/multiplication starts to matter
1912 keys %{ $join_classifications->{multiplying} || {} }
1914 # make sure if there is a supplied group_by it matches the columns compiled above
1915 # perfectly. Anything else can not be sanely executed on most databases so croak
1916 # right then and there
1917 if ($existing_group_by) {
1918 my @current_group_by = map
1919 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1924 join ("\x00", sort @current_group_by)
1926 join ("\x00", sort @{$attrs->{columns}} )
1928 $self->throw_exception (
1929 "You have just attempted a $op operation on a resultset which does group_by"
1930 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1931 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1932 . ' kind of queries. Please retry the operation with a modified group_by or'
1933 . ' without using one at all.'
1938 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1941 $guard = $storage->txn_scope_guard;
1944 for my $row ($subrs->cursor->all) {
1946 { $idcols->[$_] => $row->[$_] }
1953 my $res = $storage->$op (
1955 $op eq 'update' ? $values : (),
1959 $guard->commit if $guard;
1968 =item Arguments: \%values
1970 =item Return Value: $underlying_storage_rv
1974 Sets the specified columns in the resultset to the supplied values in a
1975 single query. Note that this will not run any accessor/set_column/update
1976 triggers, nor will it update any result object instances derived from this
1977 resultset (this includes the contents of the L<resultset cache|/set_cache>
1978 if any). See L</update_all> if you need to execute any on-update
1979 triggers or cascades defined either by you or a
1980 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1982 The return value is a pass through of what the underlying
1983 storage backend returned, and may vary. See L<DBI/execute> for the most
1988 Note that L</update> does not process/deflate any of the values passed in.
1989 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1990 ensure manually that any value passed to this method will stringify to
1991 something the RDBMS knows how to deal with. A notable example is the
1992 handling of L<DateTime> objects, for more info see:
1993 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1998 my ($self, $values) = @_;
1999 $self->throw_exception('Values for update must be a hash')
2000 unless ref $values eq 'HASH';
2002 return $self->_rs_update_delete ('update', $values);
2009 =item Arguments: \%values
2011 =item Return Value: 1
2015 Fetches all objects and updates them one at a time via
2016 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2017 triggers, while L</update> will not.
2022 my ($self, $values) = @_;
2023 $self->throw_exception('Values for update_all must be a hash')
2024 unless ref $values eq 'HASH';
2026 my $guard = $self->result_source->schema->txn_scope_guard;
2027 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2036 =item Arguments: none
2038 =item Return Value: $underlying_storage_rv
2042 Deletes the rows matching this resultset in a single query. Note that this
2043 will not run any delete triggers, nor will it alter the
2044 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2045 derived from this resultset (this includes the contents of the
2046 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2047 execute any on-delete triggers or cascades defined either by you or a
2048 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2050 The return value is a pass through of what the underlying storage backend
2051 returned, and may vary. See L<DBI/execute> for the most common case.
2057 $self->throw_exception('delete does not accept any arguments')
2060 return $self->_rs_update_delete ('delete');
2067 =item Arguments: none
2069 =item Return Value: 1
2073 Fetches all objects and deletes them one at a time via
2074 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2075 triggers, while L</delete> will not.
2081 $self->throw_exception('delete_all does not accept any arguments')
2084 my $guard = $self->result_source->schema->txn_scope_guard;
2085 $_->delete for $self->all;
2094 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2096 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2100 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2107 The context of this method call has an important effect on what is
2108 submitted to storage. In void context data is fed directly to fastpath
2109 insertion routines provided by the underlying storage (most often
2110 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2111 L<insert|DBIx::Class::Row/insert> calls on the
2112 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2113 augmentation of these methods provided by components. For example if you
2114 are using something like L<DBIx::Class::UUIDColumns> to create primary
2115 keys for you, you will find that your PKs are empty. In this case you
2116 will have to explicitly force scalar or list context in order to create
2121 In non-void (scalar or list) context, this method is simply a wrapper
2122 for L</create>. Depending on list or scalar context either a list of
2123 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2124 containing these objects is returned.
2126 When supplying data in "arrayref of arrayrefs" invocation style, the
2127 first element should be a list of column names and each subsequent
2128 element should be a data value in the earlier specified column order.
2131 $Arstist_rs->populate([
2132 [ qw( artistid name ) ],
2133 [ 100, 'A Formally Unknown Singer' ],
2134 [ 101, 'A singer that jumped the shark two albums ago' ],
2135 [ 102, 'An actually cool singer' ],
2138 For the arrayref of hashrefs style each hashref should be a structure
2139 suitable for passing to L</create>. Multi-create is also permitted with
2142 $schema->resultset("Artist")->populate([
2143 { artistid => 4, name => 'Manufactured Crap', cds => [
2144 { title => 'My First CD', year => 2006 },
2145 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2148 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2149 { title => 'My parents sold me to a record company', year => 2005 },
2150 { title => 'Why Am I So Ugly?', year => 2006 },
2151 { title => 'I Got Surgery and am now Popular', year => 2007 }
2156 If you attempt a void-context multi-create as in the example above (each
2157 Artist also has the related list of CDs), and B<do not> supply the
2158 necessary autoinc foreign key information, this method will proxy to the
2159 less efficient L</create>, and then throw the Result objects away. In this
2160 case there are obviously no benefits to using this method over L</create>.
2167 # cruft placed in standalone method
2168 my $data = $self->_normalize_populate_args(@_);
2170 return unless @$data;
2172 if(defined wantarray) {
2173 my @created = map { $self->create($_) } @$data;
2174 return wantarray ? @created : \@created;
2177 my $first = $data->[0];
2179 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2180 # it relationship data
2181 my (@rels, @columns);
2182 my $rsrc = $self->result_source;
2183 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2184 for (keys %$first) {
2185 my $ref = ref $first->{$_};
2186 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2192 my @pks = $rsrc->primary_columns;
2194 ## do the belongs_to relationships
2195 foreach my $index (0..$#$data) {
2197 # delegate to create() for any dataset without primary keys with specified relationships
2198 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2200 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2201 my @ret = $self->populate($data);
2207 foreach my $rel (@rels) {
2208 next unless ref $data->[$index]->{$rel} eq "HASH";
2209 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2210 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2211 my $related = $result->result_source->_resolve_condition(
2212 $reverse_relinfo->{cond},
2218 delete $data->[$index]->{$rel};
2219 $data->[$index] = {%{$data->[$index]}, %$related};
2221 push @columns, keys %$related if $index == 0;
2225 ## inherit the data locked in the conditions of the resultset
2226 my ($rs_data) = $self->_merge_with_rscond({});
2227 delete @{$rs_data}{@columns};
2229 ## do bulk insert on current row
2230 $rsrc->storage->insert_bulk(
2232 [@columns, keys %$rs_data],
2233 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2236 ## do the has_many relationships
2237 foreach my $item (@$data) {
2241 foreach my $rel (@rels) {
2242 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2244 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2246 my $child = $main_row->$rel;
2248 my $related = $child->result_source->_resolve_condition(
2249 $rels->{$rel}{cond},
2255 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2256 my @populate = map { {%$_, %$related} } @rows_to_add;
2258 $child->populate( \@populate );
2265 # populate() argumnets went over several incarnations
2266 # What we ultimately support is AoH
2267 sub _normalize_populate_args {
2268 my ($self, $arg) = @_;
2270 if (ref $arg eq 'ARRAY') {
2274 elsif (ref $arg->[0] eq 'HASH') {
2277 elsif (ref $arg->[0] eq 'ARRAY') {
2279 my @colnames = @{$arg->[0]};
2280 foreach my $values (@{$arg}[1 .. $#$arg]) {
2281 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2287 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2294 =item Arguments: none
2296 =item Return Value: L<$pager|Data::Page>
2300 Returns a L<Data::Page> object for the current resultset. Only makes
2301 sense for queries with a C<page> attribute.
2303 To get the full count of entries for a paged resultset, call
2304 C<total_entries> on the L<Data::Page> object.
2311 return $self->{pager} if $self->{pager};
2313 my $attrs = $self->{attrs};
2314 if (!defined $attrs->{page}) {
2315 $self->throw_exception("Can't create pager for non-paged rs");
2317 elsif ($attrs->{page} <= 0) {
2318 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2320 $attrs->{rows} ||= 10;
2322 # throw away the paging flags and re-run the count (possibly
2323 # with a subselect) to get the real total count
2324 my $count_attrs = { %$attrs };
2325 delete @{$count_attrs}{qw/rows offset page pager/};
2327 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2329 require DBIx::Class::ResultSet::Pager;
2330 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2331 sub { $total_rs->count }, #lazy-get the total
2333 $self->{attrs}{page},
2341 =item Arguments: $page_number
2343 =item Return Value: L<$resultset|/search>
2347 Returns a resultset for the $page_number page of the resultset on which page
2348 is called, where each page contains a number of rows equal to the 'rows'
2349 attribute set on the resultset (10 by default).
2354 my ($self, $page) = @_;
2355 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2362 =item Arguments: \%col_data
2364 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2368 Creates a new result object in the resultset's result class and returns
2369 it. The row is not inserted into the database at this point, call
2370 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2371 will tell you whether the result object has been inserted or not.
2373 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2378 my ($self, $values) = @_;
2380 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2383 $self->throw_exception( "new_result expects a hashref" )
2384 unless (ref $values eq 'HASH');
2386 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2388 my $new = $self->result_class->new({
2390 ( @$cols_from_relations
2391 ? (-cols_from_relations => $cols_from_relations)
2394 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2398 reftype($new) eq 'HASH'
2404 carp_unique (sprintf (
2405 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2406 $self->result_class,
2413 # _merge_with_rscond
2415 # Takes a simple hash of K/V data and returns its copy merged with the
2416 # condition already present on the resultset. Additionally returns an
2417 # arrayref of value/condition names, which were inferred from related
2418 # objects (this is needed for in-memory related objects)
2419 sub _merge_with_rscond {
2420 my ($self, $data) = @_;
2422 my (%new_data, @cols_from_relations);
2424 my $alias = $self->{attrs}{alias};
2426 if (! defined $self->{cond}) {
2427 # just massage $data below
2429 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2430 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2431 @cols_from_relations = keys %new_data;
2433 elsif (ref $self->{cond} ne 'HASH') {
2434 $self->throw_exception(
2435 "Can't abstract implicit construct, resultset condition not a hash"
2439 # precendence must be given to passed values over values inherited from
2440 # the cond, so the order here is important.
2441 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2442 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2444 while ( my($col, $value) = each %implied ) {
2445 my $vref = ref $value;
2451 (keys %$value)[0] eq '='
2453 $new_data{$col} = $value->{'='};
2455 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2456 $new_data{$col} = $value;
2463 %{ $self->_remove_alias($data, $alias) },
2466 return (\%new_data, \@cols_from_relations);
2469 # _has_resolved_attr
2471 # determines if the resultset defines at least one
2472 # of the attributes supplied
2474 # used to determine if a subquery is neccessary
2476 # supports some virtual attributes:
2478 # This will scan for any joins being present on the resultset.
2479 # It is not a mere key-search but a deep inspection of {from}
2482 sub _has_resolved_attr {
2483 my ($self, @attr_names) = @_;
2485 my $attrs = $self->_resolved_attrs;
2489 for my $n (@attr_names) {
2490 if (grep { $n eq $_ } (qw/-join/) ) {
2491 $extra_checks{$n}++;
2495 my $attr = $attrs->{$n};
2497 next if not defined $attr;
2499 if (ref $attr eq 'HASH') {
2500 return 1 if keys %$attr;
2502 elsif (ref $attr eq 'ARRAY') {
2510 # a resolved join is expressed as a multi-level from
2512 $extra_checks{-join}
2514 ref $attrs->{from} eq 'ARRAY'
2516 @{$attrs->{from}} > 1
2524 # Recursively collapse the condition.
2526 sub _collapse_cond {
2527 my ($self, $cond, $collapsed) = @_;
2531 if (ref $cond eq 'ARRAY') {
2532 foreach my $subcond (@$cond) {
2533 next unless ref $subcond; # -or
2534 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2537 elsif (ref $cond eq 'HASH') {
2538 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2539 foreach my $subcond (@{$cond->{-and}}) {
2540 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2544 foreach my $col (keys %$cond) {
2545 my $value = $cond->{$col};
2546 $collapsed->{$col} = $value;
2556 # Remove the specified alias from the specified query hash. A copy is made so
2557 # the original query is not modified.
2560 my ($self, $query, $alias) = @_;
2562 my %orig = %{ $query || {} };
2565 foreach my $key (keys %orig) {
2567 $unaliased{$key} = $orig{$key};
2570 $unaliased{$1} = $orig{$key}
2571 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2581 =item Arguments: none
2583 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2587 Returns the SQL query and bind vars associated with the invocant.
2589 This is generally used as the RHS for a subquery.
2596 my $attrs = { %{ $self->_resolved_attrs } };
2598 $self->result_source->storage->_select_args_to_query (
2599 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2607 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2609 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2613 my $artist = $schema->resultset('Artist')->find_or_new(
2614 { artist => 'fred' }, { key => 'artists' });
2616 $cd->cd_to_producer->find_or_new({ producer => $producer },
2617 { key => 'primary });
2619 Find an existing record from this resultset using L</find>. if none exists,
2620 instantiate a new result object and return it. The object will not be saved
2621 into your storage until you call L<DBIx::Class::Row/insert> on it.
2623 You most likely want this method when looking for existing rows using a unique
2624 constraint that is not the primary key, or looking for related rows.
2626 If you want objects to be saved immediately, use L</find_or_create> instead.
2628 B<Note>: Make sure to read the documentation of L</find> and understand the
2629 significance of the C<key> attribute, as its lack may skew your search, and
2630 subsequently result in spurious new objects.
2632 B<Note>: Take care when using C<find_or_new> with a table having
2633 columns with default values that you intend to be automatically
2634 supplied by the database (e.g. an auto_increment primary key column).
2635 In normal usage, the value of such columns should NOT be included at
2636 all in the call to C<find_or_new>, even when set to C<undef>.
2642 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2643 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2644 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2647 return $self->new_result($hash);
2654 =item Arguments: \%col_data
2656 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2660 Attempt to create a single new row or a row with multiple related rows
2661 in the table represented by the resultset (and related tables). This
2662 will not check for duplicate rows before inserting, use
2663 L</find_or_create> to do that.
2665 To create one row for this resultset, pass a hashref of key/value
2666 pairs representing the columns of the table and the values you wish to
2667 store. If the appropriate relationships are set up, foreign key fields
2668 can also be passed an object representing the foreign row, and the
2669 value will be set to its primary key.
2671 To create related objects, pass a hashref of related-object column values
2672 B<keyed on the relationship name>. If the relationship is of type C<multi>
2673 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2674 The process will correctly identify columns holding foreign keys, and will
2675 transparently populate them from the keys of the corresponding relation.
2676 This can be applied recursively, and will work correctly for a structure
2677 with an arbitrary depth and width, as long as the relationships actually
2678 exists and the correct column data has been supplied.
2680 Instead of hashrefs of plain related data (key/value pairs), you may
2681 also pass new or inserted objects. New objects (not inserted yet, see
2682 L</new_result>), will be inserted into their appropriate tables.
2684 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2686 Example of creating a new row.
2688 $person_rs->create({
2689 name=>"Some Person",
2690 email=>"somebody@someplace.com"
2693 Example of creating a new row and also creating rows in a related C<has_many>
2694 or C<has_one> resultset. Note Arrayref.
2697 { artistid => 4, name => 'Manufactured Crap', cds => [
2698 { title => 'My First CD', year => 2006 },
2699 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2704 Example of creating a new row and also creating a row in a related
2705 C<belongs_to> resultset. Note Hashref.
2708 title=>"Music for Silly Walks",
2711 name=>"Silly Musician",
2719 When subclassing ResultSet never attempt to override this method. Since
2720 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2721 lot of the internals simply never call it, so your override will be
2722 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2723 or L<DBIx::Class::Row/insert> depending on how early in the
2724 L</create> process you need to intervene. See also warning pertaining to
2732 my ($self, $col_data) = @_;
2733 $self->throw_exception( "create needs a hashref" )
2734 unless ref $col_data eq 'HASH';
2735 return $self->new_result($col_data)->insert;
2738 =head2 find_or_create
2742 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2744 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2748 $cd->cd_to_producer->find_or_create({ producer => $producer },
2749 { key => 'primary' });
2751 Tries to find a record based on its primary key or unique constraints; if none
2752 is found, creates one and returns that instead.
2754 my $cd = $schema->resultset('CD')->find_or_create({
2756 artist => 'Massive Attack',
2757 title => 'Mezzanine',
2761 Also takes an optional C<key> attribute, to search by a specific key or unique
2762 constraint. For example:
2764 my $cd = $schema->resultset('CD')->find_or_create(
2766 artist => 'Massive Attack',
2767 title => 'Mezzanine',
2769 { key => 'cd_artist_title' }
2772 B<Note>: Make sure to read the documentation of L</find> and understand the
2773 significance of the C<key> attribute, as its lack may skew your search, and
2774 subsequently result in spurious row creation.
2776 B<Note>: Because find_or_create() reads from the database and then
2777 possibly inserts based on the result, this method is subject to a race
2778 condition. Another process could create a record in the table after
2779 the find has completed and before the create has started. To avoid
2780 this problem, use find_or_create() inside a transaction.
2782 B<Note>: Take care when using C<find_or_create> with a table having
2783 columns with default values that you intend to be automatically
2784 supplied by the database (e.g. an auto_increment primary key column).
2785 In normal usage, the value of such columns should NOT be included at
2786 all in the call to C<find_or_create>, even when set to C<undef>.
2788 See also L</find> and L</update_or_create>. For information on how to declare
2789 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2791 If you need to know if an existing row was found or a new one created use
2792 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2793 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2796 my $cd = $schema->resultset('CD')->find_or_new({
2798 artist => 'Massive Attack',
2799 title => 'Mezzanine',
2803 if( !$cd->in_storage ) {
2810 sub find_or_create {
2812 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2813 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2814 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2817 return $self->create($hash);
2820 =head2 update_or_create
2824 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2826 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2830 $resultset->update_or_create({ col => $val, ... });
2832 Like L</find_or_create>, but if a row is found it is immediately updated via
2833 C<< $found_row->update (\%col_data) >>.
2836 Takes an optional C<key> attribute to search on a specific unique constraint.
2839 # In your application
2840 my $cd = $schema->resultset('CD')->update_or_create(
2842 artist => 'Massive Attack',
2843 title => 'Mezzanine',
2846 { key => 'cd_artist_title' }
2849 $cd->cd_to_producer->update_or_create({
2850 producer => $producer,
2856 B<Note>: Make sure to read the documentation of L</find> and understand the
2857 significance of the C<key> attribute, as its lack may skew your search, and
2858 subsequently result in spurious row creation.
2860 B<Note>: Take care when using C<update_or_create> with a table having
2861 columns with default values that you intend to be automatically
2862 supplied by the database (e.g. an auto_increment primary key column).
2863 In normal usage, the value of such columns should NOT be included at
2864 all in the call to C<update_or_create>, even when set to C<undef>.
2866 See also L</find> and L</find_or_create>. For information on how to declare
2867 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2869 If you need to know if an existing row was updated or a new one created use
2870 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2871 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2876 sub update_or_create {
2878 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2879 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2881 my $row = $self->find($cond, $attrs);
2883 $row->update($cond);
2887 return $self->create($cond);
2890 =head2 update_or_new
2894 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2896 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2900 $resultset->update_or_new({ col => $val, ... });
2902 Like L</find_or_new> but if a row is found it is immediately updated via
2903 C<< $found_row->update (\%col_data) >>.
2907 # In your application
2908 my $cd = $schema->resultset('CD')->update_or_new(
2910 artist => 'Massive Attack',
2911 title => 'Mezzanine',
2914 { key => 'cd_artist_title' }
2917 if ($cd->in_storage) {
2918 # the cd was updated
2921 # the cd is not yet in the database, let's insert it
2925 B<Note>: Make sure to read the documentation of L</find> and understand the
2926 significance of the C<key> attribute, as its lack may skew your search, and
2927 subsequently result in spurious new objects.
2929 B<Note>: Take care when using C<update_or_new> with a table having
2930 columns with default values that you intend to be automatically
2931 supplied by the database (e.g. an auto_increment primary key column).
2932 In normal usage, the value of such columns should NOT be included at
2933 all in the call to C<update_or_new>, even when set to C<undef>.
2935 See also L</find>, L</find_or_create> and L</find_or_new>.
2941 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2942 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2944 my $row = $self->find( $cond, $attrs );
2945 if ( defined $row ) {
2946 $row->update($cond);
2950 return $self->new_result($cond);
2957 =item Arguments: none
2959 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2963 Gets the contents of the cache for the resultset, if the cache is set.
2965 The cache is populated either by using the L</prefetch> attribute to
2966 L</search> or by calling L</set_cache>.
2978 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2980 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2984 Sets the contents of the cache for the resultset. Expects an arrayref
2985 of objects of the same class as those produced by the resultset. Note that
2986 if the cache is set, the resultset will return the cached objects rather
2987 than re-querying the database even if the cache attr is not set.
2989 The contents of the cache can also be populated by using the
2990 L</prefetch> attribute to L</search>.
2995 my ( $self, $data ) = @_;
2996 $self->throw_exception("set_cache requires an arrayref")
2997 if defined($data) && (ref $data ne 'ARRAY');
2998 $self->{all_cache} = $data;
3005 =item Arguments: none
3007 =item Return Value: undef
3011 Clears the cache for the resultset.
3016 shift->set_cache(undef);
3023 =item Arguments: none
3025 =item Return Value: true, if the resultset has been paginated
3033 return !!$self->{attrs}{page};
3040 =item Arguments: none
3042 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3050 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3053 =head2 related_resultset
3057 =item Arguments: $rel_name
3059 =item Return Value: L<$resultset|/search>
3063 Returns a related resultset for the supplied relationship name.
3065 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3069 sub related_resultset {
3070 my ($self, $rel) = @_;
3072 return $self->{related_resultsets}{$rel}
3073 if defined $self->{related_resultsets}{$rel};
3075 return $self->{related_resultsets}{$rel} = do {
3076 my $rsrc = $self->result_source;
3077 my $rel_info = $rsrc->relationship_info($rel);
3079 $self->throw_exception(
3080 "search_related: result source '" . $rsrc->source_name .
3081 "' has no such relationship $rel")
3084 my $attrs = $self->_chain_relationship($rel);
3086 my $join_count = $attrs->{seen_join}{$rel};
3088 my $alias = $self->result_source->storage
3089 ->relname_to_table_alias($rel, $join_count);
3091 # since this is search_related, and we already slid the select window inwards
3092 # (the select/as attrs were deleted in the beginning), we need to flip all
3093 # left joins to inner, so we get the expected results
3094 # read the comment on top of the actual function to see what this does
3095 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3098 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3099 delete @{$attrs}{qw(result_class alias)};
3103 if (my $cache = $self->get_cache) {
3104 $related_cache = [ map
3105 { @{$_->related_resultset($rel)->get_cache||[]} }
3110 my $rel_source = $rsrc->related_source($rel);
3114 # The reason we do this now instead of passing the alias to the
3115 # search_rs below is that if you wrap/overload resultset on the
3116 # source you need to know what alias it's -going- to have for things
3117 # to work sanely (e.g. RestrictWithObject wants to be able to add
3118 # extra query restrictions, and these may need to be $alias.)
3120 my $rel_attrs = $rel_source->resultset_attributes;
3121 local $rel_attrs->{alias} = $alias;
3123 $rel_source->resultset
3127 where => $attrs->{where},
3130 $new->set_cache($related_cache) if $related_cache;
3135 =head2 current_source_alias
3139 =item Arguments: none
3141 =item Return Value: $source_alias
3145 Returns the current table alias for the result source this resultset is built
3146 on, that will be used in the SQL query. Usually it is C<me>.
3148 Currently the source alias that refers to the result set returned by a
3149 L</search>/L</find> family method depends on how you got to the resultset: it's
3150 C<me> by default, but eg. L</search_related> aliases it to the related result
3151 source name (and keeps C<me> referring to the original result set). The long
3152 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3153 (and make this method unnecessary).
3155 Thus it's currently necessary to use this method in predefined queries (see
3156 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3157 source alias of the current result set:
3159 # in a result set class
3161 my ($self, $user) = @_;
3163 my $me = $self->current_source_alias;
3165 return $self->search({
3166 "$me.modified" => $user->id,
3172 sub current_source_alias {
3173 return (shift->{attrs} || {})->{alias} || 'me';
3176 =head2 as_subselect_rs
3180 =item Arguments: none
3182 =item Return Value: L<$resultset|/search>
3186 Act as a barrier to SQL symbols. The resultset provided will be made into a
3187 "virtual view" by including it as a subquery within the from clause. From this
3188 point on, any joined tables are inaccessible to ->search on the resultset (as if
3189 it were simply where-filtered without joins). For example:
3191 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3193 # 'x' now pollutes the query namespace
3195 # So the following works as expected
3196 my $ok_rs = $rs->search({'x.other' => 1});
3198 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3199 # def) we look for one row with contradictory terms and join in another table
3200 # (aliased 'x_2') which we never use
3201 my $broken_rs = $rs->search({'x.name' => 'def'});
3203 my $rs2 = $rs->as_subselect_rs;
3205 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3206 my $not_joined_rs = $rs2->search({'x.other' => 1});
3208 # works as expected: finds a 'table' row related to two x rows (abc and def)
3209 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3211 Another example of when one might use this would be to select a subset of
3212 columns in a group by clause:
3214 my $rs = $schema->resultset('Bar')->search(undef, {
3215 group_by => [qw{ id foo_id baz_id }],
3216 })->as_subselect_rs->search(undef, {
3217 columns => [qw{ id foo_id }]
3220 In the above example normally columns would have to be equal to the group by,
3221 but because we isolated the group by into a subselect the above works.
3225 sub as_subselect_rs {
3228 my $attrs = $self->_resolved_attrs;
3230 my $fresh_rs = (ref $self)->new (
3231 $self->result_source
3234 # these pieces will be locked in the subquery
3235 delete $fresh_rs->{cond};
3236 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3238 return $fresh_rs->search( {}, {
3240 $attrs->{alias} => $self->as_query,
3241 -alias => $attrs->{alias},
3242 -rsrc => $self->result_source,
3244 alias => $attrs->{alias},
3248 # This code is called by search_related, and makes sure there
3249 # is clear separation between the joins before, during, and
3250 # after the relationship. This information is needed later
3251 # in order to properly resolve prefetch aliases (any alias
3252 # with a relation_chain_depth less than the depth of the
3253 # current prefetch is not considered)
3255 # The increments happen twice per join. An even number means a
3256 # relationship specified via a search_related, whereas an odd
3257 # number indicates a join/prefetch added via attributes
3259 # Also this code will wrap the current resultset (the one we
3260 # chain to) in a subselect IFF it contains limiting attributes
3261 sub _chain_relationship {
3262 my ($self, $rel) = @_;
3263 my $source = $self->result_source;
3264 my $attrs = { %{$self->{attrs}||{}} };
3266 # we need to take the prefetch the attrs into account before we
3267 # ->_resolve_join as otherwise they get lost - captainL
3268 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3270 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3272 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3275 my @force_subq_attrs = qw/offset rows group_by having/;
3278 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3280 $self->_has_resolved_attr (@force_subq_attrs)
3282 # Nuke the prefetch (if any) before the new $rs attrs
3283 # are resolved (prefetch is useless - we are wrapping
3284 # a subquery anyway).
3285 my $rs_copy = $self->search;
3286 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3287 $rs_copy->{attrs}{join},
3288 delete $rs_copy->{attrs}{prefetch},
3293 -alias => $attrs->{alias},
3294 $attrs->{alias} => $rs_copy->as_query,
3296 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3297 $seen->{-relation_chain_depth} = 0;
3299 elsif ($attrs->{from}) { #shallow copy suffices
3300 $from = [ @{$attrs->{from}} ];
3305 -alias => $attrs->{alias},
3306 $attrs->{alias} => $source->from,
3310 my $jpath = ($seen->{-relation_chain_depth})
3311 ? $from->[-1][0]{-join_path}
3314 my @requested_joins = $source->_resolve_join(
3321 push @$from, @requested_joins;
3323 $seen->{-relation_chain_depth}++;
3325 # if $self already had a join/prefetch specified on it, the requested
3326 # $rel might very well be already included. What we do in this case
3327 # is effectively a no-op (except that we bump up the chain_depth on
3328 # the join in question so we could tell it *is* the search_related)
3331 # we consider the last one thus reverse
3332 for my $j (reverse @requested_joins) {
3333 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3334 if ($rel eq $last_j) {
3335 $j->[0]{-relation_chain_depth}++;
3341 unless ($already_joined) {
3342 push @$from, $source->_resolve_join(
3350 $seen->{-relation_chain_depth}++;
3352 return {%$attrs, from => $from, seen_join => $seen};
3355 sub _resolved_attrs {
3357 return $self->{_attrs} if $self->{_attrs};
3359 my $attrs = { %{ $self->{attrs} || {} } };
3360 my $source = $self->result_source;
3361 my $alias = $attrs->{alias};
3363 # default selection list
3364 $attrs->{columns} = [ $source->columns ]
3365 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3367 # merge selectors together
3368 for (qw/columns select as/) {
3369 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3370 if $attrs->{$_} or $attrs->{"+$_"};
3373 # disassemble columns
3375 if (my $cols = delete $attrs->{columns}) {
3376 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3377 if (ref $c eq 'HASH') {
3378 for my $as (sort keys %$c) {
3379 push @sel, $c->{$as};
3390 # when trying to weed off duplicates later do not go past this point -
3391 # everything added from here on is unbalanced "anyone's guess" stuff
3392 my $dedup_stop_idx = $#as;
3394 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3396 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3397 if $attrs->{select};
3399 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3400 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3402 # disqualify all $alias.col as-bits (inflate-map mandated)
3403 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3405 # de-duplicate the result (remove *identical* select/as pairs)
3406 # and also die on duplicate {as} pointing to different {select}s
3407 # not using a c-style for as the condition is prone to shrinkage
3410 while ($i <= $dedup_stop_idx) {
3411 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3416 elsif ($seen->{$as[$i]}++) {
3417 $self->throw_exception(
3418 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3426 $attrs->{select} = \@sel;
3427 $attrs->{as} = \@as;
3429 $attrs->{from} ||= [{
3431 -alias => $self->{attrs}{alias},
3432 $self->{attrs}{alias} => $source->from,
3435 if ( $attrs->{join} || $attrs->{prefetch} ) {
3437 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3438 if ref $attrs->{from} ne 'ARRAY';
3440 my $join = (delete $attrs->{join}) || {};
3442 if ( defined $attrs->{prefetch} ) {
3443 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3446 $attrs->{from} = # have to copy here to avoid corrupting the original
3448 @{ $attrs->{from} },
3449 $source->_resolve_join(
3452 { %{ $attrs->{seen_join} || {} } },
3453 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3454 ? $attrs->{from}[-1][0]{-join_path}
3461 if ( defined $attrs->{order_by} ) {
3462 $attrs->{order_by} = (
3463 ref( $attrs->{order_by} ) eq 'ARRAY'
3464 ? [ @{ $attrs->{order_by} } ]
3465 : [ $attrs->{order_by} || () ]
3469 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3470 $attrs->{group_by} = [ $attrs->{group_by} ];
3473 # generate the distinct induced group_by early, as prefetch will be carried via a
3474 # subquery (since a group_by is present)
3475 if (delete $attrs->{distinct}) {
3476 if ($attrs->{group_by}) {
3477 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3480 $attrs->{_grouped_by_distinct} = 1;
3481 # distinct affects only the main selection part, not what prefetch may
3483 $attrs->{group_by} = $source->storage->_group_over_selection (
3491 # generate selections based on the prefetch helper
3493 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3494 if defined $attrs->{prefetch};
3498 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3499 if $attrs->{_dark_selector};
3501 $attrs->{collapse} = 1;
3503 # this is a separate structure (we don't look in {from} directly)
3504 # as the resolver needs to shift things off the lists to work
3505 # properly (identical-prefetches on different branches)
3507 if (ref $attrs->{from} eq 'ARRAY') {
3509 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3511 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3512 next unless $j->[0]{-alias};
3513 next unless $j->[0]{-join_path};
3514 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3516 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3519 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3520 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3524 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3526 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3527 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3530 if ( 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, but this is deprecated.)
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 as
3927 L</columns> but adds columns to the selection. (You may also use the
3928 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3929 deprecated). For example:-
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.