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 @{$attrs->{from}} > 1) {
1841 ($attrs->{from}, $join_classifications) =
1842 $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1844 # any non-pruneable non-local restricting joins imply subq
1845 $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
1848 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1850 (ref $attrs->{from}[0]) ne 'HASH'
1852 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1856 # do we need anything like a subquery?
1857 if (! $needs_subq) {
1858 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1859 # a condition containing 'me' or other table prefixes will not work
1860 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1862 my $sqla = $rsrc->storage->sql_maker;
1863 local $sqla->{_dequalify_idents} = 1;
1864 \[ $sqla->_recurse_where($self->{cond}) ];
1868 # we got this far - means it is time to wrap a subquery
1869 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1871 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1877 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1878 delete $attrs->{$_} for qw/select as collapse _related_results_construction/;
1879 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1881 # this will be consumed by the pruner waaaaay down the stack
1882 $attrs->{_force_prune_multiplying_joins} = 1;
1884 my $subrs = (ref $self)->new($rsrc, $attrs);
1886 if (@$idcols == 1) {
1887 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1889 elsif ($storage->_use_multicolumn_in) {
1890 # no syntax for calling this properly yet
1891 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1892 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1893 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1898 # if all else fails - get all primary keys and operate over a ORed set
1899 # wrap in a transaction for consistency
1900 # this is where the group_by/multiplication starts to matter
1904 keys %{ $join_classifications->{multiplying} || {} }
1906 # make sure if there is a supplied group_by it matches the columns compiled above
1907 # perfectly. Anything else can not be sanely executed on most databases so croak
1908 # right then and there
1909 if ($existing_group_by) {
1910 my @current_group_by = map
1911 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1916 join ("\x00", sort @current_group_by)
1918 join ("\x00", sort @{$attrs->{columns}} )
1920 $self->throw_exception (
1921 "You have just attempted a $op operation on a resultset which does group_by"
1922 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1923 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1924 . ' kind of queries. Please retry the operation with a modified group_by or'
1925 . ' without using one at all.'
1930 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1933 $guard = $storage->txn_scope_guard;
1936 for my $row ($subrs->cursor->all) {
1938 { $idcols->[$_] => $row->[$_] }
1945 my $res = $storage->$op (
1947 $op eq 'update' ? $values : (),
1951 $guard->commit if $guard;
1960 =item Arguments: \%values
1962 =item Return Value: $underlying_storage_rv
1966 Sets the specified columns in the resultset to the supplied values in a
1967 single query. Note that this will not run any accessor/set_column/update
1968 triggers, nor will it update any result object instances derived from this
1969 resultset (this includes the contents of the L<resultset cache|/set_cache>
1970 if any). See L</update_all> if you need to execute any on-update
1971 triggers or cascades defined either by you or a
1972 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1974 The return value is a pass through of what the underlying
1975 storage backend returned, and may vary. See L<DBI/execute> for the most
1980 Note that L</update> does not process/deflate any of the values passed in.
1981 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1982 ensure manually that any value passed to this method will stringify to
1983 something the RDBMS knows how to deal with. A notable example is the
1984 handling of L<DateTime> objects, for more info see:
1985 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
1990 my ($self, $values) = @_;
1991 $self->throw_exception('Values for update must be a hash')
1992 unless ref $values eq 'HASH';
1994 return $self->_rs_update_delete ('update', $values);
2001 =item Arguments: \%values
2003 =item Return Value: 1
2007 Fetches all objects and updates them one at a time via
2008 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2009 triggers, while L</update> will not.
2014 my ($self, $values) = @_;
2015 $self->throw_exception('Values for update_all must be a hash')
2016 unless ref $values eq 'HASH';
2018 my $guard = $self->result_source->schema->txn_scope_guard;
2019 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2028 =item Arguments: none
2030 =item Return Value: $underlying_storage_rv
2034 Deletes the rows matching this resultset in a single query. Note that this
2035 will not run any delete triggers, nor will it alter the
2036 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2037 derived from this resultset (this includes the contents of the
2038 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2039 execute any on-delete triggers or cascades defined either by you or a
2040 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2042 The return value is a pass through of what the underlying storage backend
2043 returned, and may vary. See L<DBI/execute> for the most common case.
2049 $self->throw_exception('delete does not accept any arguments')
2052 return $self->_rs_update_delete ('delete');
2059 =item Arguments: none
2061 =item Return Value: 1
2065 Fetches all objects and deletes them one at a time via
2066 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2067 triggers, while L</delete> will not.
2073 $self->throw_exception('delete_all does not accept any arguments')
2076 my $guard = $self->result_source->schema->txn_scope_guard;
2077 $_->delete for $self->all;
2086 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2088 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2092 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2099 The context of this method call has an important effect on what is
2100 submitted to storage. In void context data is fed directly to fastpath
2101 insertion routines provided by the underlying storage (most often
2102 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2103 L<insert|DBIx::Class::Row/insert> calls on the
2104 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2105 augmentation of these methods provided by components. For example if you
2106 are using something like L<DBIx::Class::UUIDColumns> to create primary
2107 keys for you, you will find that your PKs are empty. In this case you
2108 will have to explicitly force scalar or list context in order to create
2113 In non-void (scalar or list) context, this method is simply a wrapper
2114 for L</create>. Depending on list or scalar context either a list of
2115 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2116 containing these objects is returned.
2118 When supplying data in "arrayref of arrayrefs" invocation style, the
2119 first element should be a list of column names and each subsequent
2120 element should be a data value in the earlier specified column order.
2123 $Arstist_rs->populate([
2124 [ qw( artistid name ) ],
2125 [ 100, 'A Formally Unknown Singer' ],
2126 [ 101, 'A singer that jumped the shark two albums ago' ],
2127 [ 102, 'An actually cool singer' ],
2130 For the arrayref of hashrefs style each hashref should be a structure
2131 suitable for passing to L</create>. Multi-create is also permitted with
2134 $schema->resultset("Artist")->populate([
2135 { artistid => 4, name => 'Manufactured Crap', cds => [
2136 { title => 'My First CD', year => 2006 },
2137 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2140 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2141 { title => 'My parents sold me to a record company', year => 2005 },
2142 { title => 'Why Am I So Ugly?', year => 2006 },
2143 { title => 'I Got Surgery and am now Popular', year => 2007 }
2148 If you attempt a void-context multi-create as in the example above (each
2149 Artist also has the related list of CDs), and B<do not> supply the
2150 necessary autoinc foreign key information, this method will proxy to the
2151 less efficient L</create>, and then throw the Result objects away. In this
2152 case there are obviously no benefits to using this method over L</create>.
2159 # cruft placed in standalone method
2160 my $data = $self->_normalize_populate_args(@_);
2162 return unless @$data;
2164 if(defined wantarray) {
2165 my @created = map { $self->create($_) } @$data;
2166 return wantarray ? @created : \@created;
2169 my $first = $data->[0];
2171 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2172 # it relationship data
2173 my (@rels, @columns);
2174 my $rsrc = $self->result_source;
2175 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2176 for (keys %$first) {
2177 my $ref = ref $first->{$_};
2178 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2184 my @pks = $rsrc->primary_columns;
2186 ## do the belongs_to relationships
2187 foreach my $index (0..$#$data) {
2189 # delegate to create() for any dataset without primary keys with specified relationships
2190 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2192 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2193 my @ret = $self->populate($data);
2199 foreach my $rel (@rels) {
2200 next unless ref $data->[$index]->{$rel} eq "HASH";
2201 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2202 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2203 my $related = $result->result_source->_resolve_condition(
2204 $reverse_relinfo->{cond},
2210 delete $data->[$index]->{$rel};
2211 $data->[$index] = {%{$data->[$index]}, %$related};
2213 push @columns, keys %$related if $index == 0;
2217 ## inherit the data locked in the conditions of the resultset
2218 my ($rs_data) = $self->_merge_with_rscond({});
2219 delete @{$rs_data}{@columns};
2221 ## do bulk insert on current row
2222 $rsrc->storage->insert_bulk(
2224 [@columns, keys %$rs_data],
2225 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2228 ## do the has_many relationships
2229 foreach my $item (@$data) {
2233 foreach my $rel (@rels) {
2234 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2236 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2238 my $child = $main_row->$rel;
2240 my $related = $child->result_source->_resolve_condition(
2241 $rels->{$rel}{cond},
2247 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2248 my @populate = map { {%$_, %$related} } @rows_to_add;
2250 $child->populate( \@populate );
2257 # populate() argumnets went over several incarnations
2258 # What we ultimately support is AoH
2259 sub _normalize_populate_args {
2260 my ($self, $arg) = @_;
2262 if (ref $arg eq 'ARRAY') {
2266 elsif (ref $arg->[0] eq 'HASH') {
2269 elsif (ref $arg->[0] eq 'ARRAY') {
2271 my @colnames = @{$arg->[0]};
2272 foreach my $values (@{$arg}[1 .. $#$arg]) {
2273 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2279 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2286 =item Arguments: none
2288 =item Return Value: L<$pager|Data::Page>
2292 Returns a L<Data::Page> object for the current resultset. Only makes
2293 sense for queries with a C<page> attribute.
2295 To get the full count of entries for a paged resultset, call
2296 C<total_entries> on the L<Data::Page> object.
2303 return $self->{pager} if $self->{pager};
2305 my $attrs = $self->{attrs};
2306 if (!defined $attrs->{page}) {
2307 $self->throw_exception("Can't create pager for non-paged rs");
2309 elsif ($attrs->{page} <= 0) {
2310 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2312 $attrs->{rows} ||= 10;
2314 # throw away the paging flags and re-run the count (possibly
2315 # with a subselect) to get the real total count
2316 my $count_attrs = { %$attrs };
2317 delete @{$count_attrs}{qw/rows offset page pager/};
2319 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2321 require DBIx::Class::ResultSet::Pager;
2322 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2323 sub { $total_rs->count }, #lazy-get the total
2325 $self->{attrs}{page},
2333 =item Arguments: $page_number
2335 =item Return Value: L<$resultset|/search>
2339 Returns a resultset for the $page_number page of the resultset on which page
2340 is called, where each page contains a number of rows equal to the 'rows'
2341 attribute set on the resultset (10 by default).
2346 my ($self, $page) = @_;
2347 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2354 =item Arguments: \%col_data
2356 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2360 Creates a new result object in the resultset's result class and returns
2361 it. The row is not inserted into the database at this point, call
2362 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2363 will tell you whether the result object has been inserted or not.
2365 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2370 my ($self, $values) = @_;
2372 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2375 $self->throw_exception( "new_result expects a hashref" )
2376 unless (ref $values eq 'HASH');
2378 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2380 my $new = $self->result_class->new({
2382 ( @$cols_from_relations
2383 ? (-cols_from_relations => $cols_from_relations)
2386 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2390 reftype($new) eq 'HASH'
2396 carp_unique (sprintf (
2397 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2398 $self->result_class,
2405 # _merge_with_rscond
2407 # Takes a simple hash of K/V data and returns its copy merged with the
2408 # condition already present on the resultset. Additionally returns an
2409 # arrayref of value/condition names, which were inferred from related
2410 # objects (this is needed for in-memory related objects)
2411 sub _merge_with_rscond {
2412 my ($self, $data) = @_;
2414 my (%new_data, @cols_from_relations);
2416 my $alias = $self->{attrs}{alias};
2418 if (! defined $self->{cond}) {
2419 # just massage $data below
2421 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2422 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2423 @cols_from_relations = keys %new_data;
2425 elsif (ref $self->{cond} ne 'HASH') {
2426 $self->throw_exception(
2427 "Can't abstract implicit construct, resultset condition not a hash"
2431 # precendence must be given to passed values over values inherited from
2432 # the cond, so the order here is important.
2433 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2434 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2436 while ( my($col, $value) = each %implied ) {
2437 my $vref = ref $value;
2443 (keys %$value)[0] eq '='
2445 $new_data{$col} = $value->{'='};
2447 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2448 $new_data{$col} = $value;
2455 %{ $self->_remove_alias($data, $alias) },
2458 return (\%new_data, \@cols_from_relations);
2461 # _has_resolved_attr
2463 # determines if the resultset defines at least one
2464 # of the attributes supplied
2466 # used to determine if a subquery is neccessary
2468 # supports some virtual attributes:
2470 # This will scan for any joins being present on the resultset.
2471 # It is not a mere key-search but a deep inspection of {from}
2474 sub _has_resolved_attr {
2475 my ($self, @attr_names) = @_;
2477 my $attrs = $self->_resolved_attrs;
2481 for my $n (@attr_names) {
2482 if (grep { $n eq $_ } (qw/-join/) ) {
2483 $extra_checks{$n}++;
2487 my $attr = $attrs->{$n};
2489 next if not defined $attr;
2491 if (ref $attr eq 'HASH') {
2492 return 1 if keys %$attr;
2494 elsif (ref $attr eq 'ARRAY') {
2502 # a resolved join is expressed as a multi-level from
2504 $extra_checks{-join}
2506 ref $attrs->{from} eq 'ARRAY'
2508 @{$attrs->{from}} > 1
2516 # Recursively collapse the condition.
2518 sub _collapse_cond {
2519 my ($self, $cond, $collapsed) = @_;
2523 if (ref $cond eq 'ARRAY') {
2524 foreach my $subcond (@$cond) {
2525 next unless ref $subcond; # -or
2526 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2529 elsif (ref $cond eq 'HASH') {
2530 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2531 foreach my $subcond (@{$cond->{-and}}) {
2532 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2536 foreach my $col (keys %$cond) {
2537 my $value = $cond->{$col};
2538 $collapsed->{$col} = $value;
2548 # Remove the specified alias from the specified query hash. A copy is made so
2549 # the original query is not modified.
2552 my ($self, $query, $alias) = @_;
2554 my %orig = %{ $query || {} };
2557 foreach my $key (keys %orig) {
2559 $unaliased{$key} = $orig{$key};
2562 $unaliased{$1} = $orig{$key}
2563 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2573 =item Arguments: none
2575 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2579 Returns the SQL query and bind vars associated with the invocant.
2581 This is generally used as the RHS for a subquery.
2588 my $attrs = { %{ $self->_resolved_attrs } };
2590 $self->result_source->storage->_select_args_to_query (
2591 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2599 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2601 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2605 my $artist = $schema->resultset('Artist')->find_or_new(
2606 { artist => 'fred' }, { key => 'artists' });
2608 $cd->cd_to_producer->find_or_new({ producer => $producer },
2609 { key => 'primary });
2611 Find an existing record from this resultset using L</find>. if none exists,
2612 instantiate a new result object and return it. The object will not be saved
2613 into your storage until you call L<DBIx::Class::Row/insert> on it.
2615 You most likely want this method when looking for existing rows using a unique
2616 constraint that is not the primary key, or looking for related rows.
2618 If you want objects to be saved immediately, use L</find_or_create> instead.
2620 B<Note>: Make sure to read the documentation of L</find> and understand the
2621 significance of the C<key> attribute, as its lack may skew your search, and
2622 subsequently result in spurious new objects.
2624 B<Note>: Take care when using C<find_or_new> with a table having
2625 columns with default values that you intend to be automatically
2626 supplied by the database (e.g. an auto_increment primary key column).
2627 In normal usage, the value of such columns should NOT be included at
2628 all in the call to C<find_or_new>, even when set to C<undef>.
2634 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2635 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2636 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2639 return $self->new_result($hash);
2646 =item Arguments: \%col_data
2648 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2652 Attempt to create a single new row or a row with multiple related rows
2653 in the table represented by the resultset (and related tables). This
2654 will not check for duplicate rows before inserting, use
2655 L</find_or_create> to do that.
2657 To create one row for this resultset, pass a hashref of key/value
2658 pairs representing the columns of the table and the values you wish to
2659 store. If the appropriate relationships are set up, foreign key fields
2660 can also be passed an object representing the foreign row, and the
2661 value will be set to its primary key.
2663 To create related objects, pass a hashref of related-object column values
2664 B<keyed on the relationship name>. If the relationship is of type C<multi>
2665 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2666 The process will correctly identify columns holding foreign keys, and will
2667 transparently populate them from the keys of the corresponding relation.
2668 This can be applied recursively, and will work correctly for a structure
2669 with an arbitrary depth and width, as long as the relationships actually
2670 exists and the correct column data has been supplied.
2672 Instead of hashrefs of plain related data (key/value pairs), you may
2673 also pass new or inserted objects. New objects (not inserted yet, see
2674 L</new_result>), will be inserted into their appropriate tables.
2676 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2678 Example of creating a new row.
2680 $person_rs->create({
2681 name=>"Some Person",
2682 email=>"somebody@someplace.com"
2685 Example of creating a new row and also creating rows in a related C<has_many>
2686 or C<has_one> resultset. Note Arrayref.
2689 { artistid => 4, name => 'Manufactured Crap', cds => [
2690 { title => 'My First CD', year => 2006 },
2691 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2696 Example of creating a new row and also creating a row in a related
2697 C<belongs_to> resultset. Note Hashref.
2700 title=>"Music for Silly Walks",
2703 name=>"Silly Musician",
2711 When subclassing ResultSet never attempt to override this method. Since
2712 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2713 lot of the internals simply never call it, so your override will be
2714 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2715 or L<DBIx::Class::Row/insert> depending on how early in the
2716 L</create> process you need to intervene. See also warning pertaining to
2724 my ($self, $col_data) = @_;
2725 $self->throw_exception( "create needs a hashref" )
2726 unless ref $col_data eq 'HASH';
2727 return $self->new_result($col_data)->insert;
2730 =head2 find_or_create
2734 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2736 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2740 $cd->cd_to_producer->find_or_create({ producer => $producer },
2741 { key => 'primary' });
2743 Tries to find a record based on its primary key or unique constraints; if none
2744 is found, creates one and returns that instead.
2746 my $cd = $schema->resultset('CD')->find_or_create({
2748 artist => 'Massive Attack',
2749 title => 'Mezzanine',
2753 Also takes an optional C<key> attribute, to search by a specific key or unique
2754 constraint. For example:
2756 my $cd = $schema->resultset('CD')->find_or_create(
2758 artist => 'Massive Attack',
2759 title => 'Mezzanine',
2761 { key => 'cd_artist_title' }
2764 B<Note>: Make sure to read the documentation of L</find> and understand the
2765 significance of the C<key> attribute, as its lack may skew your search, and
2766 subsequently result in spurious row creation.
2768 B<Note>: Because find_or_create() reads from the database and then
2769 possibly inserts based on the result, this method is subject to a race
2770 condition. Another process could create a record in the table after
2771 the find has completed and before the create has started. To avoid
2772 this problem, use find_or_create() inside a transaction.
2774 B<Note>: Take care when using C<find_or_create> with a table having
2775 columns with default values that you intend to be automatically
2776 supplied by the database (e.g. an auto_increment primary key column).
2777 In normal usage, the value of such columns should NOT be included at
2778 all in the call to C<find_or_create>, even when set to C<undef>.
2780 See also L</find> and L</update_or_create>. For information on how to declare
2781 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2783 If you need to know if an existing row was found or a new one created use
2784 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2785 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2788 my $cd = $schema->resultset('CD')->find_or_new({
2790 artist => 'Massive Attack',
2791 title => 'Mezzanine',
2795 if( !$cd->in_storage ) {
2802 sub find_or_create {
2804 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2805 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2806 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2809 return $self->create($hash);
2812 =head2 update_or_create
2816 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2818 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2822 $resultset->update_or_create({ col => $val, ... });
2824 Like L</find_or_create>, but if a row is found it is immediately updated via
2825 C<< $found_row->update (\%col_data) >>.
2828 Takes an optional C<key> attribute to search on a specific unique constraint.
2831 # In your application
2832 my $cd = $schema->resultset('CD')->update_or_create(
2834 artist => 'Massive Attack',
2835 title => 'Mezzanine',
2838 { key => 'cd_artist_title' }
2841 $cd->cd_to_producer->update_or_create({
2842 producer => $producer,
2848 B<Note>: Make sure to read the documentation of L</find> and understand the
2849 significance of the C<key> attribute, as its lack may skew your search, and
2850 subsequently result in spurious row creation.
2852 B<Note>: Take care when using C<update_or_create> with a table having
2853 columns with default values that you intend to be automatically
2854 supplied by the database (e.g. an auto_increment primary key column).
2855 In normal usage, the value of such columns should NOT be included at
2856 all in the call to C<update_or_create>, even when set to C<undef>.
2858 See also L</find> and L</find_or_create>. For information on how to declare
2859 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2861 If you need to know if an existing row was updated or a new one created use
2862 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2863 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2868 sub update_or_create {
2870 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2871 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2873 my $row = $self->find($cond, $attrs);
2875 $row->update($cond);
2879 return $self->create($cond);
2882 =head2 update_or_new
2886 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2888 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2892 $resultset->update_or_new({ col => $val, ... });
2894 Like L</find_or_new> but if a row is found it is immediately updated via
2895 C<< $found_row->update (\%col_data) >>.
2899 # In your application
2900 my $cd = $schema->resultset('CD')->update_or_new(
2902 artist => 'Massive Attack',
2903 title => 'Mezzanine',
2906 { key => 'cd_artist_title' }
2909 if ($cd->in_storage) {
2910 # the cd was updated
2913 # the cd is not yet in the database, let's insert it
2917 B<Note>: Make sure to read the documentation of L</find> and understand the
2918 significance of the C<key> attribute, as its lack may skew your search, and
2919 subsequently result in spurious new objects.
2921 B<Note>: Take care when using C<update_or_new> with a table having
2922 columns with default values that you intend to be automatically
2923 supplied by the database (e.g. an auto_increment primary key column).
2924 In normal usage, the value of such columns should NOT be included at
2925 all in the call to C<update_or_new>, even when set to C<undef>.
2927 See also L</find>, L</find_or_create> and L</find_or_new>.
2933 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2934 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2936 my $row = $self->find( $cond, $attrs );
2937 if ( defined $row ) {
2938 $row->update($cond);
2942 return $self->new_result($cond);
2949 =item Arguments: none
2951 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2955 Gets the contents of the cache for the resultset, if the cache is set.
2957 The cache is populated either by using the L</prefetch> attribute to
2958 L</search> or by calling L</set_cache>.
2970 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2972 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2976 Sets the contents of the cache for the resultset. Expects an arrayref
2977 of objects of the same class as those produced by the resultset. Note that
2978 if the cache is set, the resultset will return the cached objects rather
2979 than re-querying the database even if the cache attr is not set.
2981 The contents of the cache can also be populated by using the
2982 L</prefetch> attribute to L</search>.
2987 my ( $self, $data ) = @_;
2988 $self->throw_exception("set_cache requires an arrayref")
2989 if defined($data) && (ref $data ne 'ARRAY');
2990 $self->{all_cache} = $data;
2997 =item Arguments: none
2999 =item Return Value: undef
3003 Clears the cache for the resultset.
3008 shift->set_cache(undef);
3015 =item Arguments: none
3017 =item Return Value: true, if the resultset has been paginated
3025 return !!$self->{attrs}{page};
3032 =item Arguments: none
3034 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3042 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3045 =head2 related_resultset
3049 =item Arguments: $rel_name
3051 =item Return Value: L<$resultset|/search>
3055 Returns a related resultset for the supplied relationship name.
3057 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3061 sub related_resultset {
3062 my ($self, $rel) = @_;
3064 return $self->{related_resultsets}{$rel}
3065 if defined $self->{related_resultsets}{$rel};
3067 return $self->{related_resultsets}{$rel} = do {
3068 my $rsrc = $self->result_source;
3069 my $rel_info = $rsrc->relationship_info($rel);
3071 $self->throw_exception(
3072 "search_related: result source '" . $rsrc->source_name .
3073 "' has no such relationship $rel")
3076 my $attrs = $self->_chain_relationship($rel);
3078 my $join_count = $attrs->{seen_join}{$rel};
3080 my $alias = $self->result_source->storage
3081 ->relname_to_table_alias($rel, $join_count);
3083 # since this is search_related, and we already slid the select window inwards
3084 # (the select/as attrs were deleted in the beginning), we need to flip all
3085 # left joins to inner, so we get the expected results
3086 # read the comment on top of the actual function to see what this does
3087 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3090 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3091 delete @{$attrs}{qw(result_class alias)};
3095 if (my $cache = $self->get_cache) {
3096 $related_cache = [ map
3097 { @{$_->related_resultset($rel)->get_cache||[]} }
3102 my $rel_source = $rsrc->related_source($rel);
3106 # The reason we do this now instead of passing the alias to the
3107 # search_rs below is that if you wrap/overload resultset on the
3108 # source you need to know what alias it's -going- to have for things
3109 # to work sanely (e.g. RestrictWithObject wants to be able to add
3110 # extra query restrictions, and these may need to be $alias.)
3112 my $rel_attrs = $rel_source->resultset_attributes;
3113 local $rel_attrs->{alias} = $alias;
3115 $rel_source->resultset
3119 where => $attrs->{where},
3122 $new->set_cache($related_cache) if $related_cache;
3127 =head2 current_source_alias
3131 =item Arguments: none
3133 =item Return Value: $source_alias
3137 Returns the current table alias for the result source this resultset is built
3138 on, that will be used in the SQL query. Usually it is C<me>.
3140 Currently the source alias that refers to the result set returned by a
3141 L</search>/L</find> family method depends on how you got to the resultset: it's
3142 C<me> by default, but eg. L</search_related> aliases it to the related result
3143 source name (and keeps C<me> referring to the original result set). The long
3144 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3145 (and make this method unnecessary).
3147 Thus it's currently necessary to use this method in predefined queries (see
3148 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3149 source alias of the current result set:
3151 # in a result set class
3153 my ($self, $user) = @_;
3155 my $me = $self->current_source_alias;
3157 return $self->search({
3158 "$me.modified" => $user->id,
3164 sub current_source_alias {
3165 return (shift->{attrs} || {})->{alias} || 'me';
3168 =head2 as_subselect_rs
3172 =item Arguments: none
3174 =item Return Value: L<$resultset|/search>
3178 Act as a barrier to SQL symbols. The resultset provided will be made into a
3179 "virtual view" by including it as a subquery within the from clause. From this
3180 point on, any joined tables are inaccessible to ->search on the resultset (as if
3181 it were simply where-filtered without joins). For example:
3183 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3185 # 'x' now pollutes the query namespace
3187 # So the following works as expected
3188 my $ok_rs = $rs->search({'x.other' => 1});
3190 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3191 # def) we look for one row with contradictory terms and join in another table
3192 # (aliased 'x_2') which we never use
3193 my $broken_rs = $rs->search({'x.name' => 'def'});
3195 my $rs2 = $rs->as_subselect_rs;
3197 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3198 my $not_joined_rs = $rs2->search({'x.other' => 1});
3200 # works as expected: finds a 'table' row related to two x rows (abc and def)
3201 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3203 Another example of when one might use this would be to select a subset of
3204 columns in a group by clause:
3206 my $rs = $schema->resultset('Bar')->search(undef, {
3207 group_by => [qw{ id foo_id baz_id }],
3208 })->as_subselect_rs->search(undef, {
3209 columns => [qw{ id foo_id }]
3212 In the above example normally columns would have to be equal to the group by,
3213 but because we isolated the group by into a subselect the above works.
3217 sub as_subselect_rs {
3220 my $attrs = $self->_resolved_attrs;
3222 my $fresh_rs = (ref $self)->new (
3223 $self->result_source
3226 # these pieces will be locked in the subquery
3227 delete $fresh_rs->{cond};
3228 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3230 return $fresh_rs->search( {}, {
3232 $attrs->{alias} => $self->as_query,
3233 -alias => $attrs->{alias},
3234 -rsrc => $self->result_source,
3236 alias => $attrs->{alias},
3240 # This code is called by search_related, and makes sure there
3241 # is clear separation between the joins before, during, and
3242 # after the relationship. This information is needed later
3243 # in order to properly resolve prefetch aliases (any alias
3244 # with a relation_chain_depth less than the depth of the
3245 # current prefetch is not considered)
3247 # The increments happen twice per join. An even number means a
3248 # relationship specified via a search_related, whereas an odd
3249 # number indicates a join/prefetch added via attributes
3251 # Also this code will wrap the current resultset (the one we
3252 # chain to) in a subselect IFF it contains limiting attributes
3253 sub _chain_relationship {
3254 my ($self, $rel) = @_;
3255 my $source = $self->result_source;
3256 my $attrs = { %{$self->{attrs}||{}} };
3258 # we need to take the prefetch the attrs into account before we
3259 # ->_resolve_join as otherwise they get lost - captainL
3260 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3262 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3264 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3267 my @force_subq_attrs = qw/offset rows group_by having/;
3270 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3272 $self->_has_resolved_attr (@force_subq_attrs)
3274 # Nuke the prefetch (if any) before the new $rs attrs
3275 # are resolved (prefetch is useless - we are wrapping
3276 # a subquery anyway).
3277 my $rs_copy = $self->search;
3278 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3279 $rs_copy->{attrs}{join},
3280 delete $rs_copy->{attrs}{prefetch},
3285 -alias => $attrs->{alias},
3286 $attrs->{alias} => $rs_copy->as_query,
3288 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3289 $seen->{-relation_chain_depth} = 0;
3291 elsif ($attrs->{from}) { #shallow copy suffices
3292 $from = [ @{$attrs->{from}} ];
3297 -alias => $attrs->{alias},
3298 $attrs->{alias} => $source->from,
3302 my $jpath = ($seen->{-relation_chain_depth})
3303 ? $from->[-1][0]{-join_path}
3306 my @requested_joins = $source->_resolve_join(
3313 push @$from, @requested_joins;
3315 $seen->{-relation_chain_depth}++;
3317 # if $self already had a join/prefetch specified on it, the requested
3318 # $rel might very well be already included. What we do in this case
3319 # is effectively a no-op (except that we bump up the chain_depth on
3320 # the join in question so we could tell it *is* the search_related)
3323 # we consider the last one thus reverse
3324 for my $j (reverse @requested_joins) {
3325 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3326 if ($rel eq $last_j) {
3327 $j->[0]{-relation_chain_depth}++;
3333 unless ($already_joined) {
3334 push @$from, $source->_resolve_join(
3342 $seen->{-relation_chain_depth}++;
3344 return {%$attrs, from => $from, seen_join => $seen};
3347 sub _resolved_attrs {
3349 return $self->{_attrs} if $self->{_attrs};
3351 my $attrs = { %{ $self->{attrs} || {} } };
3352 my $source = $self->result_source;
3353 my $alias = $attrs->{alias};
3355 # default selection list
3356 $attrs->{columns} = [ $source->columns ]
3357 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3359 # merge selectors together
3360 for (qw/columns select as/) {
3361 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3362 if $attrs->{$_} or $attrs->{"+$_"};
3365 # disassemble columns
3367 if (my $cols = delete $attrs->{columns}) {
3368 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3369 if (ref $c eq 'HASH') {
3370 for my $as (sort keys %$c) {
3371 push @sel, $c->{$as};
3382 # when trying to weed off duplicates later do not go past this point -
3383 # everything added from here on is unbalanced "anyone's guess" stuff
3384 my $dedup_stop_idx = $#as;
3386 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3388 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3389 if $attrs->{select};
3391 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3392 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3394 # disqualify all $alias.col as-bits (inflate-map mandated)
3395 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3397 # de-duplicate the result (remove *identical* select/as pairs)
3398 # and also die on duplicate {as} pointing to different {select}s
3399 # not using a c-style for as the condition is prone to shrinkage
3402 while ($i <= $dedup_stop_idx) {
3403 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3408 elsif ($seen->{$as[$i]}++) {
3409 $self->throw_exception(
3410 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3418 $attrs->{select} = \@sel;
3419 $attrs->{as} = \@as;
3421 $attrs->{from} ||= [{
3423 -alias => $self->{attrs}{alias},
3424 $self->{attrs}{alias} => $source->from,
3427 if ( $attrs->{join} || $attrs->{prefetch} ) {
3429 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3430 if ref $attrs->{from} ne 'ARRAY';
3432 my $join = (delete $attrs->{join}) || {};
3434 if ( defined $attrs->{prefetch} ) {
3435 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3438 $attrs->{from} = # have to copy here to avoid corrupting the original
3440 @{ $attrs->{from} },
3441 $source->_resolve_join(
3444 { %{ $attrs->{seen_join} || {} } },
3445 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3446 ? $attrs->{from}[-1][0]{-join_path}
3453 if ( defined $attrs->{order_by} ) {
3454 $attrs->{order_by} = (
3455 ref( $attrs->{order_by} ) eq 'ARRAY'
3456 ? [ @{ $attrs->{order_by} } ]
3457 : [ $attrs->{order_by} || () ]
3461 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3462 $attrs->{group_by} = [ $attrs->{group_by} ];
3465 # generate the distinct induced group_by early, as prefetch will be carried via a
3466 # subquery (since a group_by is present)
3467 if (delete $attrs->{distinct}) {
3468 if ($attrs->{group_by}) {
3469 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3472 $attrs->{_grouped_by_distinct} = 1;
3473 # distinct affects only the main selection part, not what prefetch may
3475 $attrs->{group_by} = $source->storage->_group_over_selection($attrs);
3479 # generate selections based on the prefetch helper
3481 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3482 if defined $attrs->{prefetch};
3486 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3487 if $attrs->{_dark_selector};
3489 $attrs->{collapse} = 1;
3491 # this is a separate structure (we don't look in {from} directly)
3492 # as the resolver needs to shift things off the lists to work
3493 # properly (identical-prefetches on different branches)
3495 if (ref $attrs->{from} eq 'ARRAY') {
3497 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3499 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3500 next unless $j->[0]{-alias};
3501 next unless $j->[0]{-join_path};
3502 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3504 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3507 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3508 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3512 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3514 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3515 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3518 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3519 $attrs->{_related_results_construction} = 1;
3522 $attrs->{collapse} = 0;
3525 # run through the resulting joinstructure (starting from our current slot)
3526 # and unset collapse if proven unnesessary
3528 # also while we are at it find out if the current root source has
3529 # been premultiplied by previous related_source chaining
3531 # this allows to predict whether a root object with all other relation
3532 # data set to NULL is in fact unique
3533 if ($attrs->{collapse}) {
3535 if (ref $attrs->{from} eq 'ARRAY') {
3537 if (@{$attrs->{from}} <= 1) {
3538 # no joins - no collapse
3539 $attrs->{collapse} = 0;
3542 # find where our table-spec starts
3543 my @fromlist = @{$attrs->{from}};
3545 my $t = shift @fromlist;
3548 # me vs join from-spec distinction - a ref means non-root
3549 if (ref $t eq 'ARRAY') {
3551 $is_multi ||= ! $t->{-is_single};
3553 last if ($t->{-alias} && $t->{-alias} eq $alias);
3554 $attrs->{_main_source_premultiplied} ||= $is_multi;
3557 # no non-singles remaining, nor any premultiplication - nothing to collapse
3559 ! $attrs->{_main_source_premultiplied}
3561 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3563 $attrs->{collapse} = 0;
3569 # if we can not analyze the from - err on the side of safety
3570 $attrs->{_main_source_premultiplied} = 1;
3574 # if both page and offset are specified, produce a combined offset
3575 # even though it doesn't make much sense, this is what pre 081xx has
3577 if (my $page = delete $attrs->{page}) {
3579 ($attrs->{rows} * ($page - 1))
3581 ($attrs->{offset} || 0)
3585 return $self->{_attrs} = $attrs;
3589 my ($self, $attr) = @_;
3591 if (ref $attr eq 'HASH') {
3592 return $self->_rollout_hash($attr);
3593 } elsif (ref $attr eq 'ARRAY') {
3594 return $self->_rollout_array($attr);
3600 sub _rollout_array {
3601 my ($self, $attr) = @_;
3604 foreach my $element (@{$attr}) {
3605 if (ref $element eq 'HASH') {
3606 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3607 } elsif (ref $element eq 'ARRAY') {
3608 # XXX - should probably recurse here
3609 push( @rolled_array, @{$self->_rollout_array($element)} );
3611 push( @rolled_array, $element );
3614 return \@rolled_array;
3618 my ($self, $attr) = @_;
3621 foreach my $key (keys %{$attr}) {
3622 push( @rolled_array, { $key => $attr->{$key} } );
3624 return \@rolled_array;
3627 sub _calculate_score {
3628 my ($self, $a, $b) = @_;
3630 if (defined $a xor defined $b) {
3633 elsif (not defined $a) {
3637 if (ref $b eq 'HASH') {
3638 my ($b_key) = keys %{$b};
3639 if (ref $a eq 'HASH') {
3640 my ($a_key) = keys %{$a};
3641 if ($a_key eq $b_key) {
3642 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3647 return ($a eq $b_key) ? 1 : 0;
3650 if (ref $a eq 'HASH') {
3651 my ($a_key) = keys %{$a};
3652 return ($b eq $a_key) ? 1 : 0;
3654 return ($b eq $a) ? 1 : 0;
3659 sub _merge_joinpref_attr {
3660 my ($self, $orig, $import) = @_;
3662 return $import unless defined($orig);
3663 return $orig unless defined($import);
3665 $orig = $self->_rollout_attr($orig);
3666 $import = $self->_rollout_attr($import);
3669 foreach my $import_element ( @{$import} ) {
3670 # find best candidate from $orig to merge $b_element into
3671 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3672 foreach my $orig_element ( @{$orig} ) {
3673 my $score = $self->_calculate_score( $orig_element, $import_element );
3674 if ($score > $best_candidate->{score}) {
3675 $best_candidate->{position} = $position;
3676 $best_candidate->{score} = $score;
3680 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3681 $import_key = '' if not defined $import_key;
3683 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3684 push( @{$orig}, $import_element );
3686 my $orig_best = $orig->[$best_candidate->{position}];
3687 # merge orig_best and b_element together and replace original with merged
3688 if (ref $orig_best ne 'HASH') {
3689 $orig->[$best_candidate->{position}] = $import_element;
3690 } elsif (ref $import_element eq 'HASH') {
3691 my ($key) = keys %{$orig_best};
3692 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3695 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3698 return @$orig ? $orig : ();
3706 require Hash::Merge;
3707 my $hm = Hash::Merge->new;
3709 $hm->specify_behavior({
3712 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3714 if ($defl xor $defr) {
3715 return [ $defl ? $_[0] : $_[1] ];
3720 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3724 return [$_[0], $_[1]];
3728 return $_[1] if !defined $_[0];
3729 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3730 return [$_[0], @{$_[1]}]
3733 return [] if !defined $_[0] and !keys %{$_[1]};
3734 return [ $_[1] ] if !defined $_[0];
3735 return [ $_[0] ] if !keys %{$_[1]};
3736 return [$_[0], $_[1]]
3741 return $_[0] if !defined $_[1];
3742 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3743 return [@{$_[0]}, $_[1]]
3746 my @ret = @{$_[0]} or return $_[1];
3747 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3748 my %idx = map { $_ => 1 } @ret;
3749 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3753 return [ $_[1] ] if ! @{$_[0]};
3754 return $_[0] if !keys %{$_[1]};
3755 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3756 return [ @{$_[0]}, $_[1] ];
3761 return [] if !keys %{$_[0]} and !defined $_[1];
3762 return [ $_[0] ] if !defined $_[1];
3763 return [ $_[1] ] if !keys %{$_[0]};
3764 return [$_[0], $_[1]]
3767 return [] if !keys %{$_[0]} and !@{$_[1]};
3768 return [ $_[0] ] if !@{$_[1]};
3769 return $_[1] if !keys %{$_[0]};
3770 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3771 return [ $_[0], @{$_[1]} ];
3774 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3775 return [ $_[0] ] if !keys %{$_[1]};
3776 return [ $_[1] ] if !keys %{$_[0]};
3777 return [ $_[0] ] if $_[0] eq $_[1];
3778 return [ $_[0], $_[1] ];
3781 } => 'DBIC_RS_ATTR_MERGER');
3785 return $hm->merge ($_[1], $_[2]);
3789 sub STORABLE_freeze {
3790 my ($self, $cloning) = @_;
3791 my $to_serialize = { %$self };
3793 # A cursor in progress can't be serialized (and would make little sense anyway)
3794 # the parser can be regenerated (and can't be serialized)
3795 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3797 # nor is it sensical to store a not-yet-fired-count pager
3798 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3799 delete $to_serialize->{pager};
3802 Storable::nfreeze($to_serialize);
3805 # need this hook for symmetry
3807 my ($self, $cloning, $serialized) = @_;
3809 %$self = %{ Storable::thaw($serialized) };
3815 =head2 throw_exception
3817 See L<DBIx::Class::Schema/throw_exception> for details.
3821 sub throw_exception {
3824 if (ref $self and my $rsrc = $self->result_source) {
3825 $rsrc->throw_exception(@_)
3828 DBIx::Class::Exception->throw(@_);
3836 # XXX: FIXME: Attributes docs need clearing up
3840 Attributes are used to refine a ResultSet in various ways when
3841 searching for data. They can be passed to any method which takes an
3842 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3845 Default attributes can be set on the result class using
3846 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3847 the CAVEATS on that feature before using it!)
3849 These are in no particular order:
3855 =item Value: ( $order_by | \@order_by | \%order_by )
3859 Which column(s) to order the results by.
3861 [The full list of suitable values is documented in
3862 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3865 If a single column name, or an arrayref of names is supplied, the
3866 argument is passed through directly to SQL. The hashref syntax allows
3867 for connection-agnostic specification of ordering direction:
3869 For descending order:
3871 order_by => { -desc => [qw/col1 col2 col3/] }
3873 For explicit ascending order:
3875 order_by => { -asc => 'col' }
3877 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3878 supported, although you are strongly encouraged to use the hashref
3879 syntax as outlined above.
3885 =item Value: \@columns | \%columns | $column
3889 Shortcut to request a particular set of columns to be retrieved. Each
3890 column spec may be a string (a table column name), or a hash (in which
3891 case the key is the C<as> value, and the value is used as the C<select>
3892 expression). Adds C<me.> onto the start of any column without a C<.> in
3893 it and sets C<select> from that, then auto-populates C<as> from
3894 C<select> as normal. (You may also use the C<cols> attribute, as in
3895 earlier versions of DBIC, but this is deprecated.)
3897 Essentially C<columns> does the same as L</select> and L</as>.
3899 columns => [ 'foo', { bar => 'baz' } ]
3903 select => [qw/foo baz/],
3910 =item Value: \@columns
3914 Indicates additional columns to be selected from storage. Works the same as
3915 L</columns> but adds columns to the selection. (You may also use the
3916 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3917 deprecated). For example:-
3919 $schema->resultset('CD')->search(undef, {
3920 '+columns' => ['artist.name'],
3924 would return all CDs and include a 'name' column to the information
3925 passed to object inflation. Note that the 'artist' is the name of the
3926 column (or relationship) accessor, and 'name' is the name of the column
3927 accessor in the related table.
3929 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3930 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3931 unary plus operator before it.
3933 =head2 include_columns
3937 =item Value: \@columns
3941 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3947 =item Value: \@select_columns
3951 Indicates which columns should be selected from the storage. You can use
3952 column names, or in the case of RDBMS back ends, function or stored procedure
3955 $rs = $schema->resultset('Employee')->search(undef, {
3958 { count => 'employeeid' },
3959 { max => { length => 'name' }, -as => 'longest_name' }
3964 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3966 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3967 use L</select>, to instruct DBIx::Class how to store the result of the column.
3968 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3969 identifier aliasing. You can however alias a function, so you can use it in
3970 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3971 attribute> supplied as shown in the example above.
3973 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3974 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3975 unary plus operator before it.
3981 Indicates additional columns to be selected from storage. Works the same as
3982 L</select> but adds columns to the default selection, instead of specifying
3991 =item Value: \@inflation_names
3995 Indicates column names for object inflation. That is L</as> indicates the
3996 slot name in which the column value will be stored within the
3997 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
3998 identifier by the C<get_column> method (or via the object accessor B<if one
3999 with the same name already exists>) as shown below. The L</as> attribute has
4000 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4002 $rs = $schema->resultset('Employee')->search(undef, {
4005 { count => 'employeeid' },
4006 { max => { length => 'name' }, -as => 'longest_name' }
4015 If the object against which the search is performed already has an accessor
4016 matching a column name specified in C<as>, the value can be retrieved using
4017 the accessor as normal:
4019 my $name = $employee->name();
4021 If on the other hand an accessor does not exist in the object, you need to
4022 use C<get_column> instead:
4024 my $employee_count = $employee->get_column('employee_count');
4026 You can create your own accessors if required - see
4027 L<DBIx::Class::Manual::Cookbook> for details.
4033 Indicates additional column names for those added via L</+select>. See L</as>.
4041 =item Value: ($rel_name | \@rel_names | \%rel_names)
4045 Contains a list of relationships that should be joined for this query. For
4048 # Get CDs by Nine Inch Nails
4049 my $rs = $schema->resultset('CD')->search(
4050 { 'artist.name' => 'Nine Inch Nails' },
4051 { join => 'artist' }
4054 Can also contain a hash reference to refer to the other relation's relations.
4057 package MyApp::Schema::Track;
4058 use base qw/DBIx::Class/;
4059 __PACKAGE__->table('track');
4060 __PACKAGE__->add_columns(qw/trackid cd position title/);
4061 __PACKAGE__->set_primary_key('trackid');
4062 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4065 # In your application
4066 my $rs = $schema->resultset('Artist')->search(
4067 { 'track.title' => 'Teardrop' },
4069 join => { cd => 'track' },
4070 order_by => 'artist.name',
4074 You need to use the relationship (not the table) name in conditions,
4075 because they are aliased as such. The current table is aliased as "me", so
4076 you need to use me.column_name in order to avoid ambiguity. For example:
4078 # Get CDs from 1984 with a 'Foo' track
4079 my $rs = $schema->resultset('CD')->search(
4082 'tracks.name' => 'Foo'
4084 { join => 'tracks' }
4087 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4088 similarly for a third time). For e.g.
4090 my $rs = $schema->resultset('Artist')->search({
4091 'cds.title' => 'Down to Earth',
4092 'cds_2.title' => 'Popular',
4094 join => [ qw/cds cds/ ],
4097 will return a set of all artists that have both a cd with title 'Down
4098 to Earth' and a cd with title 'Popular'.
4100 If you want to fetch related objects from other tables as well, see L</prefetch>
4103 NOTE: An internal join-chain pruner will discard certain joins while
4104 constructing the actual SQL query, as long as the joins in question do not
4105 affect the retrieved result. This for example includes 1:1 left joins
4106 that are not part of the restriction specification (WHERE/HAVING) nor are
4107 a part of the query selection.
4109 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4115 =item Value: (0 | 1)
4119 When set to a true value, indicates that any rows fetched from joined has_many
4120 relationships are to be aggregated into the corresponding "parent" object. For
4121 example, the resultset:
4123 my $rs = $schema->resultset('CD')->search({}, {
4124 '+columns' => [ qw/ tracks.title tracks.position / ],
4129 While executing the following query:
4131 SELECT me.*, tracks.title, tracks.position
4133 LEFT JOIN track tracks
4134 ON tracks.cdid = me.cdid
4136 Will return only as many objects as there are rows in the CD source, even
4137 though the result of the query may span many rows. Each of these CD objects
4138 will in turn have multiple "Track" objects hidden behind the has_many
4139 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4140 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4141 product"), with each CD object containing exactly one of all fetched Track data.
4143 When a collapse is requested on a non-ordered resultset, an order by some
4144 unique part of the main source (the left-most table) is inserted automatically.
4145 This is done so that the resultset is allowed to be "lazy" - calling
4146 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4147 object with all of its related data.
4149 If an L</order_by> is already declared, and orders the resultset in a way that
4150 makes collapsing as described above impossible (e.g. C<< ORDER BY
4151 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4152 switch to "eager" mode and slurp the entire resultset before consturcting the
4153 first object returned by L</next>.
4155 Setting this attribute on a resultset that does not join any has_many
4156 relations is a no-op.
4158 For a more in-depth discussion, see L</PREFETCHING>.
4164 =item Value: ($rel_name | \@rel_names | \%rel_names)
4168 This attribute is a shorthand for specifying a L</join> spec, adding all
4169 columns from the joined related sources as L</+columns> and setting
4170 L</collapse> to a true value. For example, the following two queries are
4173 my $rs = $schema->resultset('Artist')->search({}, {
4174 prefetch => { cds => ['genre', 'tracks' ] },
4179 my $rs = $schema->resultset('Artist')->search({}, {
4180 join => { cds => ['genre', 'tracks' ] },
4184 { +{ "cds.$_" => "cds.$_" } }
4185 $schema->source('Artist')->related_source('cds')->columns
4188 { +{ "cds.genre.$_" => "genre.$_" } }
4189 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4192 { +{ "cds.tracks.$_" => "tracks.$_" } }
4193 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4198 Both producing the following SQL:
4200 SELECT me.artistid, me.name, me.rank, me.charfield,
4201 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4202 genre.genreid, genre.name,
4203 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4206 ON cds.artist = me.artistid
4207 LEFT JOIN genre genre
4208 ON genre.genreid = cds.genreid
4209 LEFT JOIN track tracks
4210 ON tracks.cd = cds.cdid
4211 ORDER BY me.artistid
4213 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4214 the arguments are properly merged and generally do the right thing. For
4215 example, you may want to do the following:
4217 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4218 { 'genre.genreid' => undef },
4220 join => { cds => 'genre' },
4225 Which generates the following SQL:
4227 SELECT me.artistid, me.name, me.rank, me.charfield,
4228 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4231 ON cds.artist = me.artistid
4232 LEFT JOIN genre genre
4233 ON genre.genreid = cds.genreid
4234 WHERE genre.genreid IS NULL
4235 ORDER BY me.artistid
4237 For a more in-depth discussion, see L</PREFETCHING>.
4243 =item Value: $source_alias
4247 Sets the source alias for the query. Normally, this defaults to C<me>, but
4248 nested search queries (sub-SELECTs) might need specific aliases set to
4249 reference inner queries. For example:
4252 ->related_resultset('CDs')
4253 ->related_resultset('Tracks')
4255 'track.id' => { -ident => 'none_search.id' },
4259 my $ids = $self->search({
4262 alias => 'none_search',
4263 group_by => 'none_search.id',
4264 })->get_column('id')->as_query;
4266 $self->search({ id => { -in => $ids } })
4268 This attribute is directly tied to L</current_source_alias>.
4278 Makes the resultset paged and specifies the page to retrieve. Effectively
4279 identical to creating a non-pages resultset and then calling ->page($page)
4282 If L</rows> attribute is not specified it defaults to 10 rows per page.
4284 When you have a paged resultset, L</count> will only return the number
4285 of rows in the page. To get the total, use the L</pager> and call
4286 C<total_entries> on it.
4296 Specifies the maximum number of rows for direct retrieval or the number of
4297 rows per page if the page attribute or method is used.
4303 =item Value: $offset
4307 Specifies the (zero-based) row number for the first row to be returned, or the
4308 of the first row of the first page if paging is used.
4310 =head2 software_limit
4314 =item Value: (0 | 1)
4318 When combined with L</rows> and/or L</offset> the generated SQL will not
4319 include any limit dialect stanzas. Instead the entire result will be selected
4320 as if no limits were specified, and DBIC will perform the limit locally, by
4321 artificially advancing and finishing the resulting L</cursor>.
4323 This is the recommended way of performing resultset limiting when no sane RDBMS
4324 implementation is available (e.g.
4325 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4326 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4332 =item Value: \@columns
4336 A arrayref of columns to group by. Can include columns of joined tables.
4338 group_by => [qw/ column1 column2 ... /]
4344 =item Value: $condition
4348 HAVING is a select statement attribute that is applied between GROUP BY and
4349 ORDER BY. It is applied to the after the grouping calculations have been
4352 having => { 'count_employee' => { '>=', 100 } }
4354 or with an in-place function in which case literal SQL is required:
4356 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4362 =item Value: (0 | 1)
4366 Set to 1 to group by all columns. If the resultset already has a group_by
4367 attribute, this setting is ignored and an appropriate warning is issued.
4373 Adds to the WHERE clause.
4375 # only return rows WHERE deleted IS NULL for all searches
4376 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4378 Can be overridden by passing C<< { where => undef } >> as an attribute
4381 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4387 Set to 1 to cache search results. This prevents extra SQL queries if you
4388 revisit rows in your ResultSet:
4390 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4392 while( my $artist = $resultset->next ) {
4396 $rs->first; # without cache, this would issue a query
4398 By default, searches are not cached.
4400 For more examples of using these attributes, see
4401 L<DBIx::Class::Manual::Cookbook>.
4407 =item Value: ( 'update' | 'shared' | \$scalar )
4411 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4412 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4417 DBIx::Class supports arbitrary related data prefetching from multiple related
4418 sources. Any combination of relationship types and column sets are supported.
4419 If L<collapsing|/collapse> is requested, there is an additional requirement of
4420 selecting enough data to make every individual object uniquely identifiable.
4422 Here are some more involved examples, based on the following relationship map:
4425 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4426 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4427 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4429 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4431 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4435 my $rs = $schema->resultset('Tag')->search(
4444 The initial search results in SQL like the following:
4446 SELECT tag.*, cd.*, artist.* FROM tag
4447 JOIN cd ON tag.cd = cd.cdid
4448 JOIN artist ON cd.artist = artist.artistid
4450 L<DBIx::Class> has no need to go back to the database when we access the
4451 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4454 Simple prefetches will be joined automatically, so there is no need
4455 for a C<join> attribute in the above search.
4457 The L</prefetch> attribute can be used with any of the relationship types
4458 and multiple prefetches can be specified together. Below is a more complex
4459 example that prefetches a CD's artist, its liner notes (if present),
4460 the cover image, the tracks on that CD, and the guests on those
4463 my $rs = $schema->resultset('CD')->search(
4467 { artist => 'record_label'}, # belongs_to => belongs_to
4468 'liner_note', # might_have
4469 'cover_image', # has_one
4470 { tracks => 'guests' }, # has_many => has_many
4475 This will produce SQL like the following:
4477 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4481 ON artist.artistid = me.artistid
4482 JOIN record_label record_label
4483 ON record_label.labelid = artist.labelid
4484 LEFT JOIN track tracks
4485 ON tracks.cdid = me.cdid
4486 LEFT JOIN guest guests
4487 ON guests.trackid = track.trackid
4488 LEFT JOIN liner_notes liner_note
4489 ON liner_note.cdid = me.cdid
4490 JOIN cd_artwork cover_image
4491 ON cover_image.cdid = me.cdid
4494 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4495 C<tracks>, and C<guests> of the CD will all be available through the
4496 relationship accessors without the need for additional queries to the
4501 Prefetch does a lot of deep magic. As such, it may not behave exactly
4502 as you might expect.
4508 Prefetch uses the L</cache> to populate the prefetched relationships. This
4509 may or may not be what you want.
4513 If you specify a condition on a prefetched relationship, ONLY those
4514 rows that match the prefetched condition will be fetched into that relationship.
4515 This means that adding prefetch to a search() B<may alter> what is returned by
4516 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4518 my $artist_rs = $schema->resultset('Artist')->search({
4524 my $count = $artist_rs->first->cds->count;
4526 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4528 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4530 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4532 That cmp_ok() may or may not pass depending on the datasets involved. In other
4533 words the C<WHERE> condition would apply to the entire dataset, just like
4534 it would in regular SQL. If you want to add a condition only to the "right side"
4535 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4536 condition|DBIx::Class::Relationship::Base/condition>
4540 =head1 DBIC BIND VALUES
4542 Because DBIC may need more information to bind values than just the column name
4543 and value itself, it uses a special format for both passing and receiving bind
4544 values. Each bind value should be composed of an arrayref of
4545 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4551 If present (in any form), this is what is being passed directly to bind_param.
4552 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4553 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4555 If this is specified, all other bind options described below are ignored.
4559 If present, this is used to infer the actual bind attribute by passing to
4560 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4561 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4563 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4564 currently drivers are expected to "Do the Right Thing" when given a common
4565 datatype name. (Not ideal, but that's what we got at this point.)
4569 Currently used to correctly allocate buffers for bind_param_inout().
4570 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4571 or to a sensible value based on the "data_type".
4575 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4576 explicitly specified they are never overriden). Also used by some weird DBDs,
4577 where the column name should be available at bind_param time (e.g. Oracle).
4581 For backwards compatibility and convenience, the following shortcuts are
4584 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4585 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4586 [ undef, $val ] === [ {}, $val ]
4588 =head1 AUTHOR AND CONTRIBUTORS
4590 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4594 You may distribute this code under the same terms as Perl itself.