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
11 use Data::Query::Constants;
12 use Data::Query::ExprHelpers;
13 # not importing first() as it will clash with our own method
17 # De-duplication in _merge_attr() is disabled, but left in for reference
18 # (the merger is used for other things that ought not to be de-duped)
19 *__HM_DEDUP = sub () { 0 };
29 # this is real - CDBICompat overrides it with insanity
30 # yes, prototype won't matter, but that's for now ;)
33 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
37 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
41 my $users_rs = $schema->resultset('User');
42 while( $user = $users_rs->next) {
43 print $user->username;
46 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
47 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
51 A ResultSet is an object which stores a set of conditions representing
52 a query. It is the backbone of DBIx::Class (i.e. the really
53 important/useful bit).
55 No SQL is executed on the database when a ResultSet is created, it
56 just stores all the conditions needed to create the query.
58 A basic ResultSet representing the data of an entire table is returned
59 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
60 L<Source|DBIx::Class::Manual::Glossary/Source> name.
62 my $users_rs = $schema->resultset('User');
64 A new ResultSet is returned from calling L</search> on an existing
65 ResultSet. The new one will contain all the conditions of the
66 original, plus any new conditions added in the C<search> call.
68 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
69 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
72 The query that the ResultSet represents is B<only> executed against
73 the database when these methods are called:
74 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
76 If a resultset is used in a numeric context it returns the L</count>.
77 However, if it is used in a boolean context it is B<always> true. So if
78 you want to check if a resultset has any results, you must use C<if $rs
81 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
83 If you want to make your custom ResultSet classes with L<Moose>, use a template
86 package MyApp::Schema::ResultSet::User;
89 use namespace::autoclean;
91 extends 'DBIx::Class::ResultSet';
93 sub BUILDARGS { $_[2] }
97 __PACKAGE__->meta->make_immutable;
101 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
102 clash with the regular ResultSet constructor. Alternatively, you can use:
104 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
106 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
107 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
111 =head2 Chaining resultsets
113 Let's say you've got a query that needs to be run to return some data
114 to the user. But, you have an authorization system in place that
115 prevents certain users from seeing certain information. So, you want
116 to construct the basic query in one method, but add constraints to it in
121 my $request = $self->get_request; # Get a request object somehow.
122 my $schema = $self->result_source->schema;
124 my $cd_rs = $schema->resultset('CD')->search({
125 title => $request->param('title'),
126 year => $request->param('year'),
129 $cd_rs = $self->apply_security_policy( $cd_rs );
131 return $cd_rs->all();
134 sub apply_security_policy {
143 =head3 Resolving conditions and attributes
145 When a resultset is chained from another resultset (e.g.:
146 C<< my $new_rs = $old_rs->search(\%extra_cond, \%attrs) >>), conditions
147 and attributes with the same keys need resolving.
149 If any of L</columns>, L</select>, L</as> are present, they reset the
150 original selection, and start the selection "clean".
152 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
153 are merged into the existing ones from the original resultset.
155 The L</where> and L</having> attributes, and any search conditions, are
156 merged with an SQL C<AND> to the existing condition from the original
159 All other attributes are overridden by any new ones supplied in the
162 =head2 Multiple queries
164 Since a resultset just defines a query, you can do all sorts of
165 things with it with the same object.
167 # Don't hit the DB yet.
168 my $cd_rs = $schema->resultset('CD')->search({
169 title => 'something',
173 # Each of these hits the DB individually.
174 my $count = $cd_rs->count;
175 my $most_recent = $cd_rs->get_column('date_released')->max();
176 my @records = $cd_rs->all;
178 And it's not just limited to SELECT statements.
184 $cd_rs->create({ artist => 'Fred' });
186 Which is the same as:
188 $schema->resultset('CD')->create({
189 title => 'something',
194 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
202 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
204 =item Return Value: L<$resultset|/search>
208 The resultset constructor. Takes a source object (usually a
209 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
210 L</ATTRIBUTES> below). Does not perform any queries -- these are
211 executed as needed by the other methods.
213 Generally you never construct a resultset manually. Instead you get one
215 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
216 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
219 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
225 If called on an object, proxies to L</new_result> instead, so
227 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
229 will return a CD object, not a ResultSet, and is equivalent to:
231 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
233 Please also keep in mind that many internals call L</new_result> directly,
234 so overloading this method with the idea of intercepting new result object
235 creation B<will not work>. See also warning pertaining to L</create>.
243 return $class->new_result(@_) if ref $class;
245 my ($source, $attrs) = @_;
246 $source = $source->resolve
247 if $source->isa('DBIx::Class::ResultSourceHandle');
249 $attrs = { %{$attrs||{}} };
250 delete @{$attrs}{qw(_sqlmaker_select_args _related_results_construction)};
252 if ($attrs->{page}) {
253 $attrs->{rows} ||= 10;
256 $attrs->{alias} ||= 'me';
259 result_source => $source,
260 cond => $attrs->{where},
265 # if there is a dark selector, this means we are already in a
266 # chain and the cleanup/sanification was taken care of by
268 $self->_normalize_selection($attrs)
269 unless $attrs->{_dark_selector};
272 $attrs->{result_class} || $source->result_class
282 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
284 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
288 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
289 my $new_rs = $cd_rs->search({ year => 2005 });
291 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
292 # year = 2005 OR year = 2004
294 In list context, C<< ->all() >> is called implicitly on the resultset, thus
295 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
296 To avoid that, use L</search_rs>.
298 If you need to pass in additional attributes but no additional condition,
299 call it as C<search(undef, \%attrs)>.
301 # "SELECT name, artistid FROM $artist_table"
302 my @all_artists = $schema->resultset('Artist')->search(undef, {
303 columns => [qw/name artistid/],
306 For a list of attributes that can be passed to C<search>, see
307 L</ATTRIBUTES>. For more examples of using this function, see
308 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
309 documentation for the first argument, see L<SQL::Abstract/"WHERE CLAUSES">
310 and its extension L<DBIx::Class::SQLMaker>.
312 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
316 Note that L</search> does not process/deflate any of the values passed in the
317 L<SQL::Abstract>-compatible search condition structure. This is unlike other
318 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
319 manually that any value passed to this method will stringify to something the
320 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
321 objects, for more info see:
322 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
328 my $rs = $self->search_rs( @_ );
333 elsif (defined wantarray) {
337 # we can be called by a relationship helper, which in
338 # turn may be called in void context due to some braindead
339 # overload or whatever else the user decided to be clever
340 # at this particular day. Thus limit the exception to
341 # external code calls only
342 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
343 if (caller)[0] !~ /^\QDBIx::Class::/;
353 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
355 =item Return Value: L<$resultset|/search>
359 This method does the same exact thing as search() except it will
360 always return a resultset, even in list context.
367 my $rsrc = $self->result_source;
368 my ($call_cond, $call_attrs);
370 # Special-case handling for (undef, undef) or (undef)
371 # Note that (foo => undef) is valid deprecated syntax
372 @_ = () if not scalar grep { defined $_ } @_;
378 # fish out attrs in the ($condref, $attr) case
379 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
380 ($call_cond, $call_attrs) = @_;
383 $self->throw_exception('Odd number of arguments to search')
387 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
388 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
390 for my $i (0 .. $#_) {
392 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
393 if (! defined $_[$i] or ref $_[$i] ne '');
399 # see if we can keep the cache (no $rs changes)
401 my %safe = (alias => 1, cache => 1);
402 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
405 ref $call_cond eq 'HASH' && ! keys %$call_cond
407 ref $call_cond eq 'ARRAY' && ! @$call_cond
409 $cache = $self->get_cache;
412 my $old_attrs = { %{$self->{attrs}} };
413 my ($old_having, $old_where) = delete @{$old_attrs}{qw(having where)};
415 my $new_attrs = { %$old_attrs };
417 # take care of call attrs (only if anything is changing)
418 if ($call_attrs and keys %$call_attrs) {
420 # copy for _normalize_selection
421 $call_attrs = { %$call_attrs };
423 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
425 # reset the current selector list if new selectors are supplied
426 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
427 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
430 # Normalize the new selector list (operates on the passed-in attr structure)
431 # Need to do it on every chain instead of only once on _resolved_attrs, in
432 # order to allow detection of empty vs partial 'as'
433 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
434 if $old_attrs->{_dark_selector};
435 $self->_normalize_selection ($call_attrs);
437 # start with blind overwriting merge, exclude selector attrs
438 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
439 delete @{$new_attrs}{@selector_attrs};
441 for (@selector_attrs) {
442 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
443 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
446 # older deprecated name, use only if {columns} is not there
447 if (my $c = delete $new_attrs->{cols}) {
448 carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
449 if ($new_attrs->{columns}) {
450 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
453 $new_attrs->{columns} = $c;
458 # join/prefetch use their own crazy merging heuristics
459 foreach my $key (qw/join prefetch/) {
460 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
461 if exists $call_attrs->{$key};
464 # stack binds together
465 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
469 for ($old_where, $call_cond) {
471 $new_attrs->{where} = $self->_stack_cond (
472 $_, $new_attrs->{where}
477 if (defined $old_having) {
478 $new_attrs->{having} = $self->_stack_cond (
479 $old_having, $new_attrs->{having}
483 my $rs = (ref $self)->new($rsrc, $new_attrs);
485 $rs->set_cache($cache) if ($cache);
491 sub _normalize_selection {
492 my ($self, $attrs) = @_;
495 if ( exists $attrs->{include_columns} ) {
496 carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
497 $attrs->{'+columns'} = $self->_merge_attr(
498 $attrs->{'+columns'}, delete $attrs->{include_columns}
502 # columns are always placed first, however
504 # Keep the X vs +X separation until _resolved_attrs time - this allows to
505 # delay the decision on whether to use a default select list ($rsrc->columns)
506 # allowing stuff like the remove_columns helper to work
508 # select/as +select/+as pairs need special handling - the amount of select/as
509 # elements in each pair does *not* have to be equal (think multicolumn
510 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
511 # supplied at all) - try to infer the alias, either from the -as parameter
512 # of the selector spec, or use the parameter whole if it looks like a column
513 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
514 # is ok as well), but make sure no more additions to the 'as' chain take place
515 for my $pref ('', '+') {
517 my ($sel, $as) = map {
518 my $key = "${pref}${_}";
520 my $val = [ ref $attrs->{$key} eq 'ARRAY'
522 : $attrs->{$key} || ()
524 delete $attrs->{$key};
528 if (! @$as and ! @$sel ) {
531 elsif (@$as and ! @$sel) {
532 $self->throw_exception(
533 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
537 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
538 # if any @$as has been supplied we assume the user knows what (s)he is doing
539 # and blindly keep stacking up pieces
540 unless ($attrs->{_dark_selector}) {
543 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
544 push @$as, $_->{-as};
546 # assume any plain no-space, no-parenthesis string to be a column spec
547 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
548 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
551 # if all else fails - raise a flag that no more aliasing will be allowed
553 $attrs->{_dark_selector} = {
555 string => ($dark_sel_dumper ||= do {
556 require Data::Dumper::Concise;
557 Data::Dumper::Concise::DumperObject()->Indent(0);
558 })->Values([$_])->Dump
566 elsif (@$as < @$sel) {
567 $self->throw_exception(
568 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
571 elsif ($pref and $attrs->{_dark_selector}) {
572 $self->throw_exception(
573 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
579 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
580 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
585 my ($self, $left, $right) = @_;
587 # collapse single element top-level conditions
588 # (single pass only, unlikely to need recursion)
589 for ($left, $right) {
590 if (ref $_ eq 'ARRAY') {
598 elsif (ref $_ eq 'HASH') {
599 my ($first, $more) = keys %$_;
602 if (! defined $first) {
606 elsif (! defined $more) {
607 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
610 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
617 # merge hashes with weeding out of duplicates (simple cases only)
618 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
620 # shallow copy to destroy
621 $right = { %$right };
622 for (grep { exists $right->{$_} } keys %$left) {
623 # the use of eq_deeply here is justified - the rhs of an
624 # expression can contain a lot of twisted weird stuff
625 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
628 $right = undef unless keys %$right;
632 if (defined $left xor defined $right) {
633 return defined $left ? $left : $right;
635 elsif (! defined $left) {
639 return { -and => [ $left, $right ] };
643 =head2 search_literal
645 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
646 should only be used in that context. C<search_literal> is a convenience
647 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
648 want to ensure columns are bound correctly, use L</search>.
650 See L<DBIx::Class::Manual::Cookbook/Searching> and
651 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
652 require C<search_literal>.
656 =item Arguments: $sql_fragment, @standalone_bind_values
658 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
662 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
663 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
665 Pass a literal chunk of SQL to be added to the conditional part of the
668 Example of how to use C<search> instead of C<search_literal>
670 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
671 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
676 my ($self, $sql, @bind) = @_;
678 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
681 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
688 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
690 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
694 Finds and returns a single row based on supplied criteria. Takes either a
695 hashref with the same format as L</create> (including inference of foreign
696 keys from related objects), or a list of primary key values in the same
697 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
698 declaration on the L</result_source>.
700 In either case an attempt is made to combine conditions already existing on
701 the resultset with the condition passed to this method.
703 To aid with preparing the correct query for the storage you may supply the
704 C<key> attribute, which is the name of a
705 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
706 unique constraint corresponding to the
707 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
708 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
709 to construct a query that satisfies the named unique constraint fully (
710 non-NULL values for each column member of the constraint) an exception is
713 If no C<key> is specified, the search is carried over all unique constraints
714 which are fully defined by the available condition.
716 If no such constraint is found, C<find> currently defaults to a simple
717 C<< search->(\%column_values) >> which may or may not do what you expect.
718 Note that this fallback behavior may be deprecated in further versions. If
719 you need to search with arbitrary conditions - use L</search>. If the query
720 resulting from this fallback produces more than one row, a warning to the
721 effect is issued, though only the first row is constructed and returned as
724 In addition to C<key>, L</find> recognizes and applies standard
725 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
727 Note that if you have extra concerns about the correctness of the resulting
728 query you need to specify the C<key> attribute and supply the entire condition
729 as an argument to find (since it is not always possible to perform the
730 combination of the resultset condition with the supplied one, especially if
731 the resultset condition contains literal sql).
733 For example, to find a row by its primary key:
735 my $cd = $schema->resultset('CD')->find(5);
737 You can also find a row by a specific unique constraint:
739 my $cd = $schema->resultset('CD')->find(
741 artist => 'Massive Attack',
742 title => 'Mezzanine',
744 { key => 'cd_artist_title' }
747 See also L</find_or_create> and L</update_or_create>.
753 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
755 my $rsrc = $self->result_source;
758 if (exists $attrs->{key}) {
759 $constraint_name = defined $attrs->{key}
761 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
765 # Parse out the condition from input
768 if (ref $_[0] eq 'HASH') {
769 $call_cond = { %{$_[0]} };
772 # if only values are supplied we need to default to 'primary'
773 $constraint_name = 'primary' unless defined $constraint_name;
775 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
777 $self->throw_exception(
778 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
781 $self->throw_exception (
782 'find() expects either a column/value hashref, or a list of values '
783 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
784 ) unless @c_cols == @_;
787 @{$call_cond}{@c_cols} = @_;
791 for my $key (keys %$call_cond) {
793 my $keyref = ref($call_cond->{$key})
795 my $relinfo = $rsrc->relationship_info($key)
797 my $val = delete $call_cond->{$key};
799 next if $keyref eq 'ARRAY'; # has_many for multi_create
801 my $rel_q = $rsrc->_resolve_condition(
802 $relinfo->{cond}, $val, $key, $key
804 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
805 @related{keys %$rel_q} = values %$rel_q;
809 # relationship conditions take precedence (?)
810 @{$call_cond}{keys %related} = values %related;
812 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
814 if (defined $constraint_name) {
815 $final_cond = $self->_qualify_cond_columns (
817 $self->_build_unique_cond (
825 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
826 # This means that we got here after a merger of relationship conditions
827 # in ::Relationship::Base::search_related (the row method), and furthermore
828 # the relationship is of the 'single' type. This means that the condition
829 # provided by the relationship (already attached to $self) is sufficient,
830 # as there can be only one row in the database that would satisfy the
834 # no key was specified - fall down to heuristics mode:
835 # run through all unique queries registered on the resultset, and
836 # 'OR' all qualifying queries together
837 my (@unique_queries, %seen_column_combinations);
838 for my $c_name ($rsrc->unique_constraint_names) {
839 next if $seen_column_combinations{
840 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
843 push @unique_queries, try {
844 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
848 $final_cond = @unique_queries
849 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
850 : $self->_non_unique_find_fallback ($call_cond, $attrs)
854 # Run the query, passing the result_class since it should propagate for find
855 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
856 if ($rs->_resolved_attrs->{collapse}) {
858 carp "Query returned more than one row" if $rs->next;
866 # This is a stop-gap method as agreed during the discussion on find() cleanup:
867 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
869 # It is invoked when find() is called in legacy-mode with insufficiently-unique
870 # condition. It is provided for overrides until a saner way forward is devised
872 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
873 # the road. Please adjust your tests accordingly to catch this situation early
874 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
876 # The method will not be removed without an adequately complete replacement
877 # for strict-mode enforcement
878 sub _non_unique_find_fallback {
879 my ($self, $cond, $attrs) = @_;
881 return $self->_qualify_cond_columns(
883 exists $attrs->{alias}
885 : $self->{attrs}{alias}
890 sub _qualify_cond_columns {
891 my ($self, $cond, $alias) = @_;
893 my %aliased = %$cond;
894 for (keys %aliased) {
895 $aliased{"$alias.$_"} = delete $aliased{$_}
902 sub _build_unique_cond {
903 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
905 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
907 # combination may fail if $self->{cond} is non-trivial
908 my ($final_cond) = try {
909 $self->_merge_with_rscond ($extra_cond)
914 # trim out everything not in $columns
915 $final_cond = { map {
916 exists $final_cond->{$_}
917 ? ( $_ => $final_cond->{$_} )
921 if (my @missing = grep
922 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
925 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
927 join (', ', map { "'$_'" } @missing),
934 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
936 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
938 carp_unique ( sprintf (
939 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
940 . 'values in column(s): %s). This is almost certainly not what you wanted, '
941 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
943 join (', ', map { "'$_'" } @undefs),
950 =head2 search_related
954 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
956 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
960 $new_rs = $cd_rs->search_related('artist', {
964 Searches the specified relationship, optionally specifying a condition and
965 attributes for matching records. See L</ATTRIBUTES> for more information.
967 In list context, C<< ->all() >> is called implicitly on the resultset, thus
968 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
970 See also L</search_related_rs>.
975 return shift->related_resultset(shift)->search(@_);
978 =head2 search_related_rs
980 This method works exactly the same as search_related, except that
981 it guarantees a resultset, even in list context.
985 sub search_related_rs {
986 return shift->related_resultset(shift)->search_rs(@_);
993 =item Arguments: none
995 =item Return Value: L<$cursor|DBIx::Class::Cursor>
999 Returns a storage-driven cursor to the given resultset. See
1000 L<DBIx::Class::Cursor> for more information.
1007 return $self->{cursor} ||= do {
1008 my $attrs = $self->_resolved_attrs;
1009 $self->result_source->storage->select(
1010 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1019 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1021 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1025 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1027 Inflates the first result without creating a cursor if the resultset has
1028 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1031 While this method can take an optional search condition (just like L</search>)
1032 being a fast-code-path it does not recognize search attributes. If you need to
1033 add extra joins or similar, call L</search> and then chain-call L</single> on the
1034 L<DBIx::Class::ResultSet> returned.
1040 As of 0.08100, this method enforces the assumption that the preceding
1041 query returns only one row. If more than one row is returned, you will receive
1044 Query returned more than one row
1046 In this case, you should be using L</next> or L</find> instead, or if you really
1047 know what you are doing, use the L</rows> attribute to explicitly limit the size
1050 This method will also throw an exception if it is called on a resultset prefetching
1051 has_many, as such a prefetch implies fetching multiple rows from the database in
1052 order to assemble the resulting object.
1059 my ($self, $where) = @_;
1061 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1064 my $attrs = { %{$self->_resolved_attrs} };
1066 $self->throw_exception(
1067 'single() can not be used on resultsets collapsing a has_many. Use find( \%cond ) or next() instead'
1068 ) if $attrs->{collapse};
1071 if (defined $attrs->{where}) {
1074 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1075 $where, delete $attrs->{where} ]
1078 $attrs->{where} = $where;
1082 my $data = [ $self->result_source->storage->select_single(
1083 $attrs->{from}, $attrs->{select},
1084 $attrs->{where}, $attrs
1087 return undef unless @$data;
1088 $self->{_stashed_rows} = [ $data ];
1089 $self->_construct_results->[0];
1095 # Recursively collapse the query, accumulating values for each column.
1097 sub _collapse_query {
1098 my ($self, $query, $collapsed) = @_;
1102 if (ref $query eq 'ARRAY') {
1103 foreach my $subquery (@$query) {
1104 next unless ref $subquery; # -or
1105 $collapsed = $self->_collapse_query($subquery, $collapsed);
1108 elsif (ref $query eq 'HASH') {
1109 if (keys %$query and (keys %$query)[0] eq '-and') {
1110 foreach my $subquery (@{$query->{-and}}) {
1111 $collapsed = $self->_collapse_query($subquery, $collapsed);
1115 foreach my $col (keys %$query) {
1116 my $value = $query->{$col};
1117 $collapsed->{$col}{$value}++;
1129 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1131 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1135 my $max_length = $rs->get_column('length')->max;
1137 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1142 my ($self, $column) = @_;
1143 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1151 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1153 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1157 # WHERE title LIKE '%blue%'
1158 $cd_rs = $rs->search_like({ title => '%blue%'});
1160 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1161 that this is simply a convenience method retained for ex Class::DBI users.
1162 You most likely want to use L</search> with specific operators.
1164 For more information, see L<DBIx::Class::Manual::Cookbook>.
1166 This method is deprecated and will be removed in 0.09. Use L</search()>
1167 instead. An example conversion is:
1169 ->search_like({ foo => 'bar' });
1173 ->search({ foo => { like => 'bar' } });
1180 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1181 .' Instead use ->search({ x => { -like => "y%" } })'
1182 .' (note the outer pair of {}s - they are important!)'
1184 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1185 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1186 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1187 return $class->search($query, { %$attrs });
1194 =item Arguments: $first, $last
1196 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1200 Returns a resultset or object list representing a subset of elements from the
1201 resultset slice is called on. Indexes are from 0, i.e., to get the first
1202 three records, call:
1204 my ($one, $two, $three) = $rs->slice(0, 2);
1209 my ($self, $min, $max) = @_;
1210 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1211 $attrs->{offset} = $self->{attrs}{offset} || 0;
1212 $attrs->{offset} += $min;
1213 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1214 return $self->search(undef, $attrs);
1215 #my $slice = (ref $self)->new($self->result_source, $attrs);
1216 #return (wantarray ? $slice->all : $slice);
1223 =item Arguments: none
1225 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1229 Returns the next element in the resultset (C<undef> is there is none).
1231 Can be used to efficiently iterate over records in the resultset:
1233 my $rs = $schema->resultset('CD')->search;
1234 while (my $cd = $rs->next) {
1238 Note that you need to store the resultset object, and call C<next> on it.
1239 Calling C<< resultset('Table')->next >> repeatedly will always return the
1240 first record from the resultset.
1247 if (my $cache = $self->get_cache) {
1248 $self->{all_cache_position} ||= 0;
1249 return $cache->[$self->{all_cache_position}++];
1252 if ($self->{attrs}{cache}) {
1253 delete $self->{pager};
1254 $self->{all_cache_position} = 1;
1255 return ($self->all)[0];
1258 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1260 $self->{_stashed_results} = $self->_construct_results
1263 return shift @{$self->{_stashed_results}};
1266 # Constructs as many results as it can in one pass while respecting
1267 # cursor laziness. Several modes of operation:
1269 # * Always builds everything present in @{$self->{_stashed_rows}}
1270 # * If called with $fetch_all true - pulls everything off the cursor and
1271 # builds all result structures (or objects) in one pass
1272 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1273 # and if the resultset is ordered properly by the left side:
1274 # * Fetches stuff off the cursor until the "master object" changes,
1275 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1277 # * Just fetches, and collapses/constructs everything as if $fetch_all
1278 # was requested (there is no other way to collapse except for an
1280 # * If no collapse is requested - just get the next row, construct and
1282 sub _construct_results {
1283 my ($self, $fetch_all) = @_;
1285 my $rsrc = $self->result_source;
1286 my $attrs = $self->_resolved_attrs;
1291 ! $attrs->{order_by}
1295 my @pcols = $rsrc->primary_columns
1297 # default order for collapsing unless the user asked for something
1298 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
1299 $attrs->{_ordered_for_collapse} = 1;
1300 $attrs->{_order_is_artificial} = 1;
1303 # this will be used as both initial raw-row collector AND as a RV of
1304 # _construct_results. Not regrowing the array twice matters a lot...
1305 # a surprising amount actually
1306 my $rows = delete $self->{_stashed_rows};
1308 my $cursor; # we may not need one at all
1310 my $did_fetch_all = $fetch_all;
1313 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1314 $rows = [ ($rows ? @$rows : ()), $self->cursor->all ];
1316 elsif( $attrs->{collapse} ) {
1318 # a cursor will need to be closed over in case of collapse
1319 $cursor = $self->cursor;
1321 $attrs->{_ordered_for_collapse} = (
1327 ->_main_source_order_by_portion_is_stable($rsrc, $attrs->{order_by}, $attrs->{where})
1329 ) unless defined $attrs->{_ordered_for_collapse};
1331 if (! $attrs->{_ordered_for_collapse}) {
1334 # instead of looping over ->next, use ->all in stealth mode
1335 # *without* calling a ->reset afterwards
1336 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1337 if (! $cursor->{_done}) {
1338 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1339 $cursor->{_done} = 1;
1344 if (! $did_fetch_all and ! @{$rows||[]} ) {
1345 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1346 $cursor ||= $self->cursor;
1347 if (scalar (my @r = $cursor->next) ) {
1352 return undef unless @{$rows||[]};
1354 # sanity check - people are too clever for their own good
1355 if ($attrs->{collapse} and my $aliastypes = $attrs->{_sqlmaker_select_args}[3]{_aliastypes} ) {
1357 my $multiplied_selectors;
1358 for my $sel_alias ( grep { $_ ne $attrs->{alias} } keys %{ $aliastypes->{selecting} } ) {
1360 $aliastypes->{multiplying}{$sel_alias}
1362 scalar grep { $aliastypes->{multiplying}{(values %$_)[0]} } @{ $aliastypes->{selecting}{$sel_alias}{-parents} }
1364 $multiplied_selectors->{$_} = 1 for values %{$aliastypes->{selecting}{$sel_alias}{-seen_columns}}
1368 for my $i (0 .. $#{$attrs->{as}} ) {
1369 my $sel = $attrs->{select}[$i];
1371 if (ref $sel eq 'SCALAR') {
1374 elsif( ref $sel eq 'REF' and ref $$sel eq 'ARRAY' ) {
1378 $self->throw_exception(
1379 'Result collapse not possible - selection from a has_many source redirected to the main object'
1380 ) if ($multiplied_selectors->{$sel} and $attrs->{as}[$i] !~ /\./);
1384 # hotspot - skip the setter
1385 my $res_class = $self->_result_class;
1387 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1388 $res_class->can ('inflate_result')
1389 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1392 my $infmap = $attrs->{as};
1394 $self->{_result_inflator}{is_core_row} = ( (
1397 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1398 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1400 $self->{_result_inflator}{is_hri} = ( (
1401 ! $self->{_result_inflator}{is_core_row}
1404 require DBIx::Class::ResultClass::HashRefInflator
1406 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1408 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1411 if (! $attrs->{_related_results_construction}) {
1412 # construct a much simpler array->hash folder for the one-table cases right here
1413 if ($self->{_result_inflator}{is_hri}) {
1414 for my $r (@$rows) {
1415 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1418 # FIXME SUBOPTIMAL this is a very very very hot spot
1419 # while rather optimal we can *still* do much better, by
1420 # building a smarter Row::inflate_result(), and
1421 # switch to feeding it data via a much leaner interface
1423 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1424 # this particular resultset size
1425 elsif (@$rows < 60) {
1426 for my $r (@$rows) {
1427 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1432 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1433 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1439 $self->{_result_inflator}{is_hri} ? 'hri'
1440 : $self->{_result_inflator}{is_core_row} ? 'classic_pruning'
1441 : 'classic_nonpruning'
1444 # $args and $attrs to _mk_row_parser are separated to delineate what is
1445 # core collapser stuff and what is dbic $rs specific
1446 @{$self->{_row_parser}{$parser_type}}{qw(cref nullcheck)} = $rsrc->_mk_row_parser({
1448 inflate_map => $infmap,
1449 collapse => $attrs->{collapse},
1450 premultiplied => $attrs->{_main_source_premultiplied},
1451 hri_style => $self->{_result_inflator}{is_hri},
1452 prune_null_branches => $self->{_result_inflator}{is_hri} || $self->{_result_inflator}{is_core_row},
1453 }, $attrs) unless $self->{_row_parser}{$parser_type}{cref};
1455 # column_info metadata historically hasn't been too reliable.
1456 # We need to start fixing this somehow (the collapse resolver
1457 # can't work without it). Add an explicit check for the *main*
1458 # result, hopefully this will gradually weed out such errors
1460 # FIXME - this is a temporary kludge that reduces performance
1461 # It is however necessary for the time being
1462 my ($unrolled_non_null_cols_to_check, $err);
1464 if (my $check_non_null_cols = $self->{_row_parser}{$parser_type}{nullcheck} ) {
1467 'Collapse aborted due to invalid ResultSource metadata - the following '
1468 . 'selections are declared non-nullable but NULLs were retrieved: '
1472 COL: for my $i (@$check_non_null_cols) {
1473 ! defined $_->[$i] and push @violating_idx, $i and next COL for @$rows;
1476 $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
1479 $unrolled_non_null_cols_to_check = join (',', @$check_non_null_cols);
1483 ($did_fetch_all or ! $attrs->{collapse}) ? undef
1484 : defined $unrolled_non_null_cols_to_check ? eval sprintf <<'EOS', $unrolled_non_null_cols_to_check
1486 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1487 my @r = $cursor->next or return;
1488 if (my @violating_idx = grep { ! defined $r[$_] } (%s) ) {
1489 $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
1495 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1496 my @r = $cursor->next or return;
1501 $self->{_row_parser}{$parser_type}{cref}->(
1503 $next_cref ? ( $next_cref, $self->{_stashed_rows} = [] ) : (),
1506 # Special-case multi-object HRI - there is no $inflator_cref pass
1507 unless ($self->{_result_inflator}{is_hri}) {
1508 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows
1512 # The @$rows check seems odd at first - why wouldn't we want to warn
1513 # regardless? The issue is things like find() etc, where the user
1514 # *knows* only one result will come back. In these cases the ->all
1515 # is not a pessimization, but rather something we actually want
1517 'Unable to properly collapse has_many results in iterator mode due '
1518 . 'to order criteria - performed an eager cursor slurp underneath. '
1519 . 'Consider using ->all() instead'
1520 ) if ( ! $fetch_all and @$rows > 1 );
1525 =head2 result_source
1529 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1531 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1535 An accessor for the primary ResultSource object from which this ResultSet
1542 =item Arguments: $result_class?
1544 =item Return Value: $result_class
1548 An accessor for the class to use when creating result objects. Defaults to
1549 C<< result_source->result_class >> - which in most cases is the name of the
1550 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1552 Note that changing the result_class will also remove any components
1553 that were originally loaded in the source class via
1554 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1555 in the original source class will not run.
1560 my ($self, $result_class) = @_;
1561 if ($result_class) {
1563 # don't fire this for an object
1564 $self->ensure_class_loaded($result_class)
1565 unless ref($result_class);
1567 if ($self->get_cache) {
1568 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1570 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1571 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1572 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1575 $self->_result_class($result_class);
1577 delete $self->{_result_inflator};
1579 $self->_result_class;
1586 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1588 =item Return Value: $count
1592 Performs an SQL C<COUNT> with the same query as the resultset was built
1593 with to find the number of elements. Passing arguments is equivalent to
1594 C<< $rs->search ($cond, \%attrs)->count >>
1600 return $self->search(@_)->count if @_ and defined $_[0];
1601 return scalar @{ $self->get_cache } if $self->get_cache;
1603 my $attrs = { %{ $self->_resolved_attrs } };
1605 # this is a little optimization - it is faster to do the limit
1606 # adjustments in software, instead of a subquery
1607 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1610 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1611 $crs = $self->_count_subq_rs ($attrs);
1614 $crs = $self->_count_rs ($attrs);
1616 my $count = $crs->next;
1618 $count -= $offset if $offset;
1619 $count = $rows if $rows and $rows < $count;
1620 $count = 0 if ($count < 0);
1629 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1631 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1635 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1636 This can be very handy for subqueries:
1638 ->search( { amount => $some_rs->count_rs->as_query } )
1640 As with regular resultsets the SQL query will be executed only after
1641 the resultset is accessed via L</next> or L</all>. That would return
1642 the same single value obtainable via L</count>.
1648 return $self->search(@_)->count_rs if @_;
1650 # this may look like a lack of abstraction (count() does about the same)
1651 # but in fact an _rs *must* use a subquery for the limits, as the
1652 # software based limiting can not be ported if this $rs is to be used
1653 # in a subquery itself (i.e. ->as_query)
1654 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1655 return $self->_count_subq_rs($self->{_attrs});
1658 return $self->_count_rs($self->{_attrs});
1663 # returns a ResultSetColumn object tied to the count query
1666 my ($self, $attrs) = @_;
1668 my $rsrc = $self->result_source;
1670 my $tmp_attrs = { %$attrs };
1671 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1672 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1674 # overwrite the selector (supplied by the storage)
1675 $rsrc->resultset_class->new($rsrc, {
1677 select => $rsrc->storage->_count_select ($rsrc, $attrs),
1679 })->get_column ('count');
1683 # same as above but uses a subquery
1685 sub _count_subq_rs {
1686 my ($self, $attrs) = @_;
1688 my $rsrc = $self->result_source;
1690 my $sub_attrs = { %$attrs };
1691 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1692 delete @{$sub_attrs}{qw/collapse columns as select order_by for/};
1694 # if we multi-prefetch we group_by something unique, as this is what we would
1695 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1696 if ( $attrs->{collapse} ) {
1697 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1698 $rsrc->_identifying_column_set || $self->throw_exception(
1699 'Unable to construct a unique group_by criteria properly collapsing the '
1700 . 'has_many prefetch before count()'
1705 # Calculate subquery selector
1706 if (my $g = $sub_attrs->{group_by}) {
1708 my $sql_maker = $rsrc->storage->sql_maker;
1710 # necessary as the group_by may refer to aliased functions
1712 for my $sel (@{$attrs->{select}}) {
1713 $sel_index->{$sel->{-as}} = $sel
1714 if (ref $sel eq 'HASH' and $sel->{-as});
1717 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1718 # also look for named aggregates referred in the having clause
1719 # having often contains scalarrefs - thus parse it out entirely
1721 if ($attrs->{having}) {
1722 local $sql_maker->{having_bind};
1723 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1724 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1725 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1726 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1727 # if we don't unset it we screw up retarded but unfortunately working
1728 # 'MAX(foo.bar)' => { '>', 3 }
1729 $sql_maker->{name_sep} = '';
1732 $sql_maker->clear_renderer;
1733 $sql_maker->clear_converter;
1735 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1737 my $having_sql = $sql_maker->_render_sqla(where => $attrs->{having});
1739 $sql_maker->clear_renderer;
1740 $sql_maker->clear_converter;
1744 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1745 # and if all fails for an utterly naive quoted scalar-with-function
1746 while ($having_sql =~ /
1747 (?: $rquote $sep)? $lquote (.+?) $rquote
1749 [\s,] \w+ \. (\w+) [\s,]
1751 [\s,] $lquote (.+?) $rquote [\s,]
1753 my $part = $1 || $2 || $3; # one of them matched if we got here
1754 unless ($seen_having{$part}++) {
1761 my $colpiece = $sel_index->{$_} || $_;
1763 # unqualify join-based group_by's. Arcane but possible query
1764 # also horrible horrible hack to alias a column (not a func.)
1765 # (probably need to introduce SQLA syntax)
1766 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1769 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1771 push @{$sub_attrs->{select}}, $colpiece;
1775 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1776 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1779 return $rsrc->resultset_class
1780 ->new ($rsrc, $sub_attrs)
1782 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1783 ->get_column ('count');
1787 =head2 count_literal
1789 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1790 should only be used in that context. See L</search_literal> for further info.
1794 =item Arguments: $sql_fragment, @standalone_bind_values
1796 =item Return Value: $count
1800 Counts the results in a literal query. Equivalent to calling L</search_literal>
1801 with the passed arguments, then L</count>.
1805 sub count_literal { shift->search_literal(@_)->count; }
1811 =item Arguments: none
1813 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1817 Returns all elements in the resultset.
1824 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1827 delete @{$self}{qw/_stashed_rows _stashed_results/};
1829 if (my $c = $self->get_cache) {
1833 $self->cursor->reset;
1835 my $objs = $self->_construct_results('fetch_all') || [];
1837 $self->set_cache($objs) if $self->{attrs}{cache};
1846 =item Arguments: none
1848 =item Return Value: $self
1852 Resets the resultset's cursor, so you can iterate through the elements again.
1853 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1861 delete @{$self}{qw/_stashed_rows _stashed_results/};
1862 $self->{all_cache_position} = 0;
1863 $self->cursor->reset;
1871 =item Arguments: none
1873 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1877 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1878 an object for the first result (or C<undef> if the resultset is empty).
1883 return $_[0]->reset->next;
1889 # Determines whether and what type of subquery is required for the $rs operation.
1890 # If grouping is necessary either supplies its own, or verifies the current one
1891 # After all is done delegates to the proper storage method.
1893 sub _rs_update_delete {
1894 my ($self, $op, $values) = @_;
1896 my $rsrc = $self->result_source;
1897 my $storage = $rsrc->schema->storage;
1899 my $attrs = { %{$self->_resolved_attrs} };
1901 my $join_classifications;
1902 my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
1904 # do we need a subquery for any reason?
1906 defined $existing_group_by
1908 # if {from} is unparseable wrap a subq
1909 ref($attrs->{from}) ne 'ARRAY'
1911 # limits call for a subq
1912 $self->_has_resolved_attr(qw/rows offset/)
1915 # simplify the joinmap, so we can further decide if a subq is necessary
1916 if (!$needs_subq and @{$attrs->{from}} > 1) {
1918 ($attrs->{from}, $join_classifications) =
1919 $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1921 # any non-pruneable non-local restricting joins imply subq
1922 $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
1925 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1927 (ref $attrs->{from}[0]) ne 'HASH'
1929 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1933 # do we need anything like a subquery?
1934 if (! $needs_subq) {
1935 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1936 # a condition containing 'me' or other table prefixes will not work
1937 # at all - so we convert the WHERE to a dq tree now, dequalify all
1938 # identifiers found therein via a scan across the tree, and then use
1939 # \{} style to pass the result onwards for use in the final query
1940 if ($self->{cond}) {
1942 my $converter = $rsrc->storage->sql_maker->converter;
1944 DQ_IDENTIFIER ,=> sub { $_ = [ $_->[-1] ] for $_[0]->{elements} }
1945 }, my $where_dq = $converter->_where_to_dq($self->{cond}));
1951 # we got this far - means it is time to wrap a subquery
1952 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1954 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1960 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1961 delete $attrs->{$_} for qw/select as collapse/;
1962 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1964 # this will be consumed by the pruner waaaaay down the stack
1965 $attrs->{_force_prune_multiplying_joins} = 1;
1967 my $subrs = (ref $self)->new($rsrc, $attrs);
1969 if (@$idcols == 1) {
1970 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1972 elsif ($storage->_use_multicolumn_in) {
1973 # no syntax for calling this properly yet
1974 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1975 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1976 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1981 # if all else fails - get all primary keys and operate over a ORed set
1982 # wrap in a transaction for consistency
1983 # this is where the group_by/multiplication starts to matter
1987 keys %{ $join_classifications->{multiplying} || {} }
1989 # make sure if there is a supplied group_by it matches the columns compiled above
1990 # perfectly. Anything else can not be sanely executed on most databases so croak
1991 # right then and there
1992 if ($existing_group_by) {
1993 my @current_group_by = map
1994 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1999 join ("\x00", sort @current_group_by)
2001 join ("\x00", sort @{$attrs->{columns}} )
2003 $self->throw_exception (
2004 "You have just attempted a $op operation on a resultset which does group_by"
2005 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
2006 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
2007 . ' kind of queries. Please retry the operation with a modified group_by or'
2008 . ' without using one at all.'
2013 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
2016 $guard = $storage->txn_scope_guard;
2019 for my $row ($subrs->cursor->all) {
2021 { $idcols->[$_] => $row->[$_] }
2028 my $res = $storage->$op (
2030 $op eq 'update' ? $values : (),
2034 $guard->commit if $guard;
2043 =item Arguments: \%values
2045 =item Return Value: $underlying_storage_rv
2049 Sets the specified columns in the resultset to the supplied values in a
2050 single query. Note that this will not run any accessor/set_column/update
2051 triggers, nor will it update any result object instances derived from this
2052 resultset (this includes the contents of the L<resultset cache|/set_cache>
2053 if any). See L</update_all> if you need to execute any on-update
2054 triggers or cascades defined either by you or a
2055 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2057 The return value is a pass through of what the underlying
2058 storage backend returned, and may vary. See L<DBI/execute> for the most
2063 Note that L</update> does not process/deflate any of the values passed in.
2064 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
2065 ensure manually that any value passed to this method will stringify to
2066 something the RDBMS knows how to deal with. A notable example is the
2067 handling of L<DateTime> objects, for more info see:
2068 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
2073 my ($self, $values) = @_;
2074 $self->throw_exception('Values for update must be a hash')
2075 unless ref $values eq 'HASH';
2077 return $self->_rs_update_delete ('update', $values);
2084 =item Arguments: \%values
2086 =item Return Value: 1
2090 Fetches all objects and updates them one at a time via
2091 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2092 triggers, while L</update> will not.
2097 my ($self, $values) = @_;
2098 $self->throw_exception('Values for update_all must be a hash')
2099 unless ref $values eq 'HASH';
2101 my $guard = $self->result_source->schema->txn_scope_guard;
2102 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2111 =item Arguments: none
2113 =item Return Value: $underlying_storage_rv
2117 Deletes the rows matching this resultset in a single query. Note that this
2118 will not run any delete triggers, nor will it alter the
2119 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2120 derived from this resultset (this includes the contents of the
2121 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2122 execute any on-delete triggers or cascades defined either by you or a
2123 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2125 The return value is a pass through of what the underlying storage backend
2126 returned, and may vary. See L<DBI/execute> for the most common case.
2132 $self->throw_exception('delete does not accept any arguments')
2135 return $self->_rs_update_delete ('delete');
2142 =item Arguments: none
2144 =item Return Value: 1
2148 Fetches all objects and deletes them one at a time via
2149 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2150 triggers, while L</delete> will not.
2156 $self->throw_exception('delete_all does not accept any arguments')
2159 my $guard = $self->result_source->schema->txn_scope_guard;
2160 $_->delete for $self->all;
2169 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2171 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2175 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2182 The context of this method call has an important effect on what is
2183 submitted to storage. In void context data is fed directly to fastpath
2184 insertion routines provided by the underlying storage (most often
2185 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2186 L<insert|DBIx::Class::Row/insert> calls on the
2187 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2188 augmentation of these methods provided by components. For example if you
2189 are using something like L<DBIx::Class::UUIDColumns> to create primary
2190 keys for you, you will find that your PKs are empty. In this case you
2191 will have to explicitly force scalar or list context in order to create
2196 In non-void (scalar or list) context, this method is simply a wrapper
2197 for L</create>. Depending on list or scalar context either a list of
2198 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2199 containing these objects is returned.
2201 When supplying data in "arrayref of arrayrefs" invocation style, the
2202 first element should be a list of column names and each subsequent
2203 element should be a data value in the earlier specified column order.
2206 $schema->resultset("Artist")->populate([
2207 [ qw( artistid name ) ],
2208 [ 100, 'A Formally Unknown Singer' ],
2209 [ 101, 'A singer that jumped the shark two albums ago' ],
2210 [ 102, 'An actually cool singer' ],
2213 For the arrayref of hashrefs style each hashref should be a structure
2214 suitable for passing to L</create>. Multi-create is also permitted with
2217 $schema->resultset("Artist")->populate([
2218 { artistid => 4, name => 'Manufactured Crap', cds => [
2219 { title => 'My First CD', year => 2006 },
2220 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2223 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2224 { title => 'My parents sold me to a record company', year => 2005 },
2225 { title => 'Why Am I So Ugly?', year => 2006 },
2226 { title => 'I Got Surgery and am now Popular', year => 2007 }
2231 If you attempt a void-context multi-create as in the example above (each
2232 Artist also has the related list of CDs), and B<do not> supply the
2233 necessary autoinc foreign key information, this method will proxy to the
2234 less efficient L</create>, and then throw the Result objects away. In this
2235 case there are obviously no benefits to using this method over L</create>.
2242 # cruft placed in standalone method
2243 my $data = $self->_normalize_populate_args(@_);
2245 return unless @$data;
2247 if(defined wantarray) {
2248 my @created = map { $self->create($_) } @$data;
2249 return wantarray ? @created : \@created;
2252 my $first = $data->[0];
2254 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2255 # it relationship data
2256 my (@rels, @columns);
2257 my $rsrc = $self->result_source;
2258 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2259 for (keys %$first) {
2260 my $ref = ref $first->{$_};
2261 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2267 my @pks = $rsrc->primary_columns;
2269 ## do the belongs_to relationships
2270 foreach my $index (0..$#$data) {
2272 # delegate to create() for any dataset without primary keys with specified relationships
2273 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2275 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2276 my @ret = $self->populate($data);
2282 foreach my $rel (@rels) {
2283 next unless ref $data->[$index]->{$rel} eq "HASH";
2284 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2285 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2286 my $related = $result->result_source->_resolve_condition(
2287 $reverse_relinfo->{cond},
2293 delete $data->[$index]->{$rel};
2294 $data->[$index] = {%{$data->[$index]}, %$related};
2296 push @columns, keys %$related if $index == 0;
2300 ## inherit the data locked in the conditions of the resultset
2301 my ($rs_data) = $self->_merge_with_rscond({});
2302 delete @{$rs_data}{@columns};
2304 ## do bulk insert on current row
2305 $rsrc->storage->insert_bulk(
2307 [@columns, keys %$rs_data],
2308 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2311 ## do the has_many relationships
2312 foreach my $item (@$data) {
2316 foreach my $rel (@rels) {
2317 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2319 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2321 my $child = $main_row->$rel;
2323 my $related = $child->result_source->_resolve_condition(
2324 $rels->{$rel}{cond},
2330 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2331 my @populate = map { {%$_, %$related} } @rows_to_add;
2333 $child->populate( \@populate );
2340 # populate() arguments went over several incarnations
2341 # What we ultimately support is AoH
2342 sub _normalize_populate_args {
2343 my ($self, $arg) = @_;
2345 if (ref $arg eq 'ARRAY') {
2349 elsif (ref $arg->[0] eq 'HASH') {
2352 elsif (ref $arg->[0] eq 'ARRAY') {
2354 my @colnames = @{$arg->[0]};
2355 foreach my $values (@{$arg}[1 .. $#$arg]) {
2356 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2362 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2369 =item Arguments: none
2371 =item Return Value: L<$pager|Data::Page>
2375 Returns a L<Data::Page> object for the current resultset. Only makes
2376 sense for queries with a C<page> attribute.
2378 To get the full count of entries for a paged resultset, call
2379 C<total_entries> on the L<Data::Page> object.
2386 return $self->{pager} if $self->{pager};
2388 my $attrs = $self->{attrs};
2389 if (!defined $attrs->{page}) {
2390 $self->throw_exception("Can't create pager for non-paged rs");
2392 elsif ($attrs->{page} <= 0) {
2393 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2395 $attrs->{rows} ||= 10;
2397 # throw away the paging flags and re-run the count (possibly
2398 # with a subselect) to get the real total count
2399 my $count_attrs = { %$attrs };
2400 delete @{$count_attrs}{qw/rows offset page pager/};
2402 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2404 require DBIx::Class::ResultSet::Pager;
2405 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2406 sub { $total_rs->count }, #lazy-get the total
2408 $self->{attrs}{page},
2416 =item Arguments: $page_number
2418 =item Return Value: L<$resultset|/search>
2422 Returns a resultset for the $page_number page of the resultset on which page
2423 is called, where each page contains a number of rows equal to the 'rows'
2424 attribute set on the resultset (10 by default).
2429 my ($self, $page) = @_;
2430 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2437 =item Arguments: \%col_data
2439 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2443 Creates a new result object in the resultset's result class and returns
2444 it. The row is not inserted into the database at this point, call
2445 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2446 will tell you whether the result object has been inserted or not.
2448 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2453 my ($self, $values) = @_;
2455 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2458 $self->throw_exception( "new_result expects a hashref" )
2459 unless (ref $values eq 'HASH');
2461 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2463 my $new = $self->result_class->new({
2465 ( @$cols_from_relations
2466 ? (-cols_from_relations => $cols_from_relations)
2469 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2473 reftype($new) eq 'HASH'
2479 carp_unique (sprintf (
2480 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2481 $self->result_class,
2488 # _merge_with_rscond
2490 # Takes a simple hash of K/V data and returns its copy merged with the
2491 # condition already present on the resultset. Additionally returns an
2492 # arrayref of value/condition names, which were inferred from related
2493 # objects (this is needed for in-memory related objects)
2494 sub _merge_with_rscond {
2495 my ($self, $data) = @_;
2497 my (%new_data, @cols_from_relations);
2499 my $alias = $self->{attrs}{alias};
2501 if (! defined $self->{cond}) {
2502 # just massage $data below
2504 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2505 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2506 @cols_from_relations = keys %new_data;
2508 elsif (ref $self->{cond} ne 'HASH') {
2509 $self->throw_exception(
2510 "Can't abstract implicit construct, resultset condition not a hash"
2514 # precedence must be given to passed values over values inherited from
2515 # the cond, so the order here is important.
2516 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2517 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2519 while ( my($col, $value) = each %implied ) {
2520 my $vref = ref $value;
2526 (keys %$value)[0] eq '='
2528 $new_data{$col} = $value->{'='};
2530 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2531 $new_data{$col} = $value;
2538 %{ $self->_remove_alias($data, $alias) },
2541 return (\%new_data, \@cols_from_relations);
2544 # _has_resolved_attr
2546 # determines if the resultset defines at least one
2547 # of the attributes supplied
2549 # used to determine if a subquery is necessary
2551 # supports some virtual attributes:
2553 # This will scan for any joins being present on the resultset.
2554 # It is not a mere key-search but a deep inspection of {from}
2557 sub _has_resolved_attr {
2558 my ($self, @attr_names) = @_;
2560 my $attrs = $self->_resolved_attrs;
2564 for my $n (@attr_names) {
2565 if (grep { $n eq $_ } (qw/-join/) ) {
2566 $extra_checks{$n}++;
2570 my $attr = $attrs->{$n};
2572 next if not defined $attr;
2574 if (ref $attr eq 'HASH') {
2575 return 1 if keys %$attr;
2577 elsif (ref $attr eq 'ARRAY') {
2585 # a resolved join is expressed as a multi-level from
2587 $extra_checks{-join}
2589 ref $attrs->{from} eq 'ARRAY'
2591 @{$attrs->{from}} > 1
2599 # Recursively collapse the condition.
2601 sub _collapse_cond {
2602 my ($self, $cond, $collapsed) = @_;
2606 if (ref $cond eq 'ARRAY') {
2607 foreach my $subcond (@$cond) {
2608 next unless ref $subcond; # -or
2609 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2612 elsif (ref $cond eq 'HASH') {
2613 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2614 foreach my $subcond (@{$cond->{-and}}) {
2615 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2619 foreach my $col (keys %$cond) {
2620 my $value = $cond->{$col};
2621 $collapsed->{$col} = $value;
2631 # Remove the specified alias from the specified query hash. A copy is made so
2632 # the original query is not modified.
2635 my ($self, $query, $alias) = @_;
2637 my %orig = %{ $query || {} };
2640 foreach my $key (keys %orig) {
2642 $unaliased{$key} = $orig{$key};
2645 $unaliased{$1} = $orig{$key}
2646 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2656 =item Arguments: none
2658 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2662 Returns the SQL query and bind vars associated with the invocant.
2664 This is generally used as the RHS for a subquery.
2671 my $attrs = { %{ $self->_resolved_attrs } };
2673 my $aq = $self->result_source->storage->_select_args_to_query (
2674 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2677 $self->{_attrs}{_sqlmaker_select_args} = $attrs->{_sqlmaker_select_args};
2686 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2688 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2692 my $artist = $schema->resultset('Artist')->find_or_new(
2693 { artist => 'fred' }, { key => 'artists' });
2695 $cd->cd_to_producer->find_or_new({ producer => $producer },
2696 { key => 'primary' });
2698 Find an existing record from this resultset using L</find>. if none exists,
2699 instantiate a new result object and return it. The object will not be saved
2700 into your storage until you call L<DBIx::Class::Row/insert> on it.
2702 You most likely want this method when looking for existing rows using a unique
2703 constraint that is not the primary key, or looking for related rows.
2705 If you want objects to be saved immediately, use L</find_or_create> instead.
2707 B<Note>: Make sure to read the documentation of L</find> and understand the
2708 significance of the C<key> attribute, as its lack may skew your search, and
2709 subsequently result in spurious new objects.
2711 B<Note>: Take care when using C<find_or_new> with a table having
2712 columns with default values that you intend to be automatically
2713 supplied by the database (e.g. an auto_increment primary key column).
2714 In normal usage, the value of such columns should NOT be included at
2715 all in the call to C<find_or_new>, even when set to C<undef>.
2721 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2722 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2723 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2726 return $self->new_result($hash);
2733 =item Arguments: \%col_data
2735 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2739 Attempt to create a single new row or a row with multiple related rows
2740 in the table represented by the resultset (and related tables). This
2741 will not check for duplicate rows before inserting, use
2742 L</find_or_create> to do that.
2744 To create one row for this resultset, pass a hashref of key/value
2745 pairs representing the columns of the table and the values you wish to
2746 store. If the appropriate relationships are set up, foreign key fields
2747 can also be passed an object representing the foreign row, and the
2748 value will be set to its primary key.
2750 To create related objects, pass a hashref of related-object column values
2751 B<keyed on the relationship name>. If the relationship is of type C<multi>
2752 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2753 The process will correctly identify columns holding foreign keys, and will
2754 transparently populate them from the keys of the corresponding relation.
2755 This can be applied recursively, and will work correctly for a structure
2756 with an arbitrary depth and width, as long as the relationships actually
2757 exists and the correct column data has been supplied.
2759 Instead of hashrefs of plain related data (key/value pairs), you may
2760 also pass new or inserted objects. New objects (not inserted yet, see
2761 L</new_result>), will be inserted into their appropriate tables.
2763 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2765 Example of creating a new row.
2767 $person_rs->create({
2768 name=>"Some Person",
2769 email=>"somebody@someplace.com"
2772 Example of creating a new row and also creating rows in a related C<has_many>
2773 or C<has_one> resultset. Note Arrayref.
2776 { artistid => 4, name => 'Manufactured Crap', cds => [
2777 { title => 'My First CD', year => 2006 },
2778 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2783 Example of creating a new row and also creating a row in a related
2784 C<belongs_to> resultset. Note Hashref.
2787 title=>"Music for Silly Walks",
2790 name=>"Silly Musician",
2798 When subclassing ResultSet never attempt to override this method. Since
2799 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2800 lot of the internals simply never call it, so your override will be
2801 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2802 or L<DBIx::Class::Row/insert> depending on how early in the
2803 L</create> process you need to intervene. See also warning pertaining to
2811 my ($self, $col_data) = @_;
2812 $self->throw_exception( "create needs a hashref" )
2813 unless ref $col_data eq 'HASH';
2814 return $self->new_result($col_data)->insert;
2817 =head2 find_or_create
2821 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2823 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2827 $cd->cd_to_producer->find_or_create({ producer => $producer },
2828 { key => 'primary' });
2830 Tries to find a record based on its primary key or unique constraints; if none
2831 is found, creates one and returns that instead.
2833 my $cd = $schema->resultset('CD')->find_or_create({
2835 artist => 'Massive Attack',
2836 title => 'Mezzanine',
2840 Also takes an optional C<key> attribute, to search by a specific key or unique
2841 constraint. For example:
2843 my $cd = $schema->resultset('CD')->find_or_create(
2845 artist => 'Massive Attack',
2846 title => 'Mezzanine',
2848 { key => 'cd_artist_title' }
2851 B<Note>: Make sure to read the documentation of L</find> and understand the
2852 significance of the C<key> attribute, as its lack may skew your search, and
2853 subsequently result in spurious row creation.
2855 B<Note>: Because find_or_create() reads from the database and then
2856 possibly inserts based on the result, this method is subject to a race
2857 condition. Another process could create a record in the table after
2858 the find has completed and before the create has started. To avoid
2859 this problem, use find_or_create() inside a transaction.
2861 B<Note>: Take care when using C<find_or_create> with a table having
2862 columns with default values that you intend to be automatically
2863 supplied by the database (e.g. an auto_increment primary key column).
2864 In normal usage, the value of such columns should NOT be included at
2865 all in the call to C<find_or_create>, even when set to C<undef>.
2867 See also L</find> and L</update_or_create>. For information on how to declare
2868 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2870 If you need to know if an existing row was found or a new one created use
2871 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2872 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2875 my $cd = $schema->resultset('CD')->find_or_new({
2877 artist => 'Massive Attack',
2878 title => 'Mezzanine',
2882 if( !$cd->in_storage ) {
2889 sub find_or_create {
2891 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2892 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2893 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2896 return $self->create($hash);
2899 =head2 update_or_create
2903 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2905 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2909 $resultset->update_or_create({ col => $val, ... });
2911 Like L</find_or_create>, but if a row is found it is immediately updated via
2912 C<< $found_row->update (\%col_data) >>.
2915 Takes an optional C<key> attribute to search on a specific unique constraint.
2918 # In your application
2919 my $cd = $schema->resultset('CD')->update_or_create(
2921 artist => 'Massive Attack',
2922 title => 'Mezzanine',
2925 { key => 'cd_artist_title' }
2928 $cd->cd_to_producer->update_or_create({
2929 producer => $producer,
2935 B<Note>: Make sure to read the documentation of L</find> and understand the
2936 significance of the C<key> attribute, as its lack may skew your search, and
2937 subsequently result in spurious row creation.
2939 B<Note>: Take care when using C<update_or_create> with a table having
2940 columns with default values that you intend to be automatically
2941 supplied by the database (e.g. an auto_increment primary key column).
2942 In normal usage, the value of such columns should NOT be included at
2943 all in the call to C<update_or_create>, even when set to C<undef>.
2945 See also L</find> and L</find_or_create>. For information on how to declare
2946 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2948 If you need to know if an existing row was updated or a new one created use
2949 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2950 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2955 sub update_or_create {
2957 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2958 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2960 my $row = $self->find($cond, $attrs);
2962 $row->update($cond);
2966 return $self->create($cond);
2969 =head2 update_or_new
2973 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2975 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2979 $resultset->update_or_new({ col => $val, ... });
2981 Like L</find_or_new> but if a row is found it is immediately updated via
2982 C<< $found_row->update (\%col_data) >>.
2986 # In your application
2987 my $cd = $schema->resultset('CD')->update_or_new(
2989 artist => 'Massive Attack',
2990 title => 'Mezzanine',
2993 { key => 'cd_artist_title' }
2996 if ($cd->in_storage) {
2997 # the cd was updated
3000 # the cd is not yet in the database, let's insert it
3004 B<Note>: Make sure to read the documentation of L</find> and understand the
3005 significance of the C<key> attribute, as its lack may skew your search, and
3006 subsequently result in spurious new objects.
3008 B<Note>: Take care when using C<update_or_new> with a table having
3009 columns with default values that you intend to be automatically
3010 supplied by the database (e.g. an auto_increment primary key column).
3011 In normal usage, the value of such columns should NOT be included at
3012 all in the call to C<update_or_new>, even when set to C<undef>.
3014 See also L</find>, L</find_or_create> and L</find_or_new>.
3020 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
3021 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
3023 my $row = $self->find( $cond, $attrs );
3024 if ( defined $row ) {
3025 $row->update($cond);
3029 return $self->new_result($cond);
3036 =item Arguments: none
3038 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
3042 Gets the contents of the cache for the resultset, if the cache is set.
3044 The cache is populated either by using the L</prefetch> attribute to
3045 L</search> or by calling L</set_cache>.
3057 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3059 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3063 Sets the contents of the cache for the resultset. Expects an arrayref
3064 of objects of the same class as those produced by the resultset. Note that
3065 if the cache is set, the resultset will return the cached objects rather
3066 than re-querying the database even if the cache attr is not set.
3068 The contents of the cache can also be populated by using the
3069 L</prefetch> attribute to L</search>.
3074 my ( $self, $data ) = @_;
3075 $self->throw_exception("set_cache requires an arrayref")
3076 if defined($data) && (ref $data ne 'ARRAY');
3077 $self->{all_cache} = $data;
3084 =item Arguments: none
3086 =item Return Value: undef
3090 Clears the cache for the resultset.
3095 shift->set_cache(undef);
3102 =item Arguments: none
3104 =item Return Value: true, if the resultset has been paginated
3112 return !!$self->{attrs}{page};
3119 =item Arguments: none
3121 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3129 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3132 =head2 related_resultset
3136 =item Arguments: $rel_name
3138 =item Return Value: L<$resultset|/search>
3142 Returns a related resultset for the supplied relationship name.
3144 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3148 sub related_resultset {
3149 my ($self, $rel) = @_;
3151 return $self->{related_resultsets}{$rel}
3152 if defined $self->{related_resultsets}{$rel};
3154 return $self->{related_resultsets}{$rel} = do {
3155 my $rsrc = $self->result_source;
3156 my $rel_info = $rsrc->relationship_info($rel);
3158 $self->throw_exception(
3159 "search_related: result source '" . $rsrc->source_name .
3160 "' has no such relationship $rel")
3163 my $attrs = $self->_chain_relationship($rel);
3165 my $join_count = $attrs->{seen_join}{$rel};
3167 my $alias = $self->result_source->storage
3168 ->relname_to_table_alias($rel, $join_count);
3170 # since this is search_related, and we already slid the select window inwards
3171 # (the select/as attrs were deleted in the beginning), we need to flip all
3172 # left joins to inner, so we get the expected results
3173 # read the comment on top of the actual function to see what this does
3174 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3177 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3178 delete @{$attrs}{qw(result_class alias)};
3180 my $rel_source = $rsrc->related_source($rel);
3184 # The reason we do this now instead of passing the alias to the
3185 # search_rs below is that if you wrap/overload resultset on the
3186 # source you need to know what alias it's -going- to have for things
3187 # to work sanely (e.g. RestrictWithObject wants to be able to add
3188 # extra query restrictions, and these may need to be $alias.)
3190 my $rel_attrs = $rel_source->resultset_attributes;
3191 local $rel_attrs->{alias} = $alias;
3193 $rel_source->resultset
3197 where => $attrs->{where},
3201 if (my $cache = $self->get_cache) {
3202 my @related_cache = map
3203 { @{$_->related_resultset($rel)->get_cache||[]} }
3207 $new->set_cache(\@related_cache) if @related_cache;
3214 =head2 current_source_alias
3218 =item Arguments: none
3220 =item Return Value: $source_alias
3224 Returns the current table alias for the result source this resultset is built
3225 on, that will be used in the SQL query. Usually it is C<me>.
3227 Currently the source alias that refers to the result set returned by a
3228 L</search>/L</find> family method depends on how you got to the resultset: it's
3229 C<me> by default, but eg. L</search_related> aliases it to the related result
3230 source name (and keeps C<me> referring to the original result set). The long
3231 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3232 (and make this method unnecessary).
3234 Thus it's currently necessary to use this method in predefined queries (see
3235 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3236 source alias of the current result set:
3238 # in a result set class
3240 my ($self, $user) = @_;
3242 my $me = $self->current_source_alias;
3244 return $self->search({
3245 "$me.modified" => $user->id,
3251 sub current_source_alias {
3252 return (shift->{attrs} || {})->{alias} || 'me';
3255 =head2 as_subselect_rs
3259 =item Arguments: none
3261 =item Return Value: L<$resultset|/search>
3265 Act as a barrier to SQL symbols. The resultset provided will be made into a
3266 "virtual view" by including it as a subquery within the from clause. From this
3267 point on, any joined tables are inaccessible to ->search on the resultset (as if
3268 it were simply where-filtered without joins). For example:
3270 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3272 # 'x' now pollutes the query namespace
3274 # So the following works as expected
3275 my $ok_rs = $rs->search({'x.other' => 1});
3277 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3278 # def) we look for one row with contradictory terms and join in another table
3279 # (aliased 'x_2') which we never use
3280 my $broken_rs = $rs->search({'x.name' => 'def'});
3282 my $rs2 = $rs->as_subselect_rs;
3284 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3285 my $not_joined_rs = $rs2->search({'x.other' => 1});
3287 # works as expected: finds a 'table' row related to two x rows (abc and def)
3288 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3290 Another example of when one might use this would be to select a subset of
3291 columns in a group by clause:
3293 my $rs = $schema->resultset('Bar')->search(undef, {
3294 group_by => [qw{ id foo_id baz_id }],
3295 })->as_subselect_rs->search(undef, {
3296 columns => [qw{ id foo_id }]
3299 In the above example normally columns would have to be equal to the group by,
3300 but because we isolated the group by into a subselect the above works.
3304 sub as_subselect_rs {
3307 my $attrs = $self->_resolved_attrs;
3309 my $fresh_rs = (ref $self)->new (
3310 $self->result_source
3313 # these pieces will be locked in the subquery
3314 delete $fresh_rs->{cond};
3315 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3317 return $fresh_rs->search( {}, {
3319 $attrs->{alias} => $self->as_query,
3320 -alias => $attrs->{alias},
3321 -rsrc => $self->result_source,
3323 alias => $attrs->{alias},
3327 # This code is called by search_related, and makes sure there
3328 # is clear separation between the joins before, during, and
3329 # after the relationship. This information is needed later
3330 # in order to properly resolve prefetch aliases (any alias
3331 # with a relation_chain_depth less than the depth of the
3332 # current prefetch is not considered)
3334 # The increments happen twice per join. An even number means a
3335 # relationship specified via a search_related, whereas an odd
3336 # number indicates a join/prefetch added via attributes
3338 # Also this code will wrap the current resultset (the one we
3339 # chain to) in a subselect IFF it contains limiting attributes
3340 sub _chain_relationship {
3341 my ($self, $rel) = @_;
3342 my $source = $self->result_source;
3343 my $attrs = { %{$self->{attrs}||{}} };
3345 # we need to take the prefetch the attrs into account before we
3346 # ->_resolve_join as otherwise they get lost - captainL
3347 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3349 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3351 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3354 my @force_subq_attrs = qw/offset rows group_by having/;
3357 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3359 $self->_has_resolved_attr (@force_subq_attrs)
3361 # Nuke the prefetch (if any) before the new $rs attrs
3362 # are resolved (prefetch is useless - we are wrapping
3363 # a subquery anyway).
3364 my $rs_copy = $self->search;
3365 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3366 $rs_copy->{attrs}{join},
3367 delete $rs_copy->{attrs}{prefetch},
3372 -alias => $attrs->{alias},
3373 $attrs->{alias} => $rs_copy->as_query,
3375 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3376 $seen->{-relation_chain_depth} = 0;
3378 elsif ($attrs->{from}) { #shallow copy suffices
3379 $from = [ @{$attrs->{from}} ];
3384 -alias => $attrs->{alias},
3385 $attrs->{alias} => $source->from,
3389 my $jpath = ($seen->{-relation_chain_depth})
3390 ? $from->[-1][0]{-join_path}
3393 my @requested_joins = $source->_resolve_join(
3400 push @$from, @requested_joins;
3402 $seen->{-relation_chain_depth}++;
3404 # if $self already had a join/prefetch specified on it, the requested
3405 # $rel might very well be already included. What we do in this case
3406 # is effectively a no-op (except that we bump up the chain_depth on
3407 # the join in question so we could tell it *is* the search_related)
3410 # we consider the last one thus reverse
3411 for my $j (reverse @requested_joins) {
3412 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3413 if ($rel eq $last_j) {
3414 $j->[0]{-relation_chain_depth}++;
3420 unless ($already_joined) {
3421 push @$from, $source->_resolve_join(
3429 $seen->{-relation_chain_depth}++;
3431 return {%$attrs, from => $from, seen_join => $seen};
3434 sub _resolved_attrs {
3436 return $self->{_attrs} if $self->{_attrs};
3438 my $attrs = { %{ $self->{attrs} || {} } };
3439 my $source = $self->result_source;
3440 my $alias = $attrs->{alias};
3442 # default selection list
3443 $attrs->{columns} = [ $source->columns ]
3444 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3446 # merge selectors together
3447 for (qw/columns select as/) {
3448 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3449 if $attrs->{$_} or $attrs->{"+$_"};
3452 # disassemble columns
3454 if (my $cols = delete $attrs->{columns}) {
3455 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3456 if (ref $c eq 'HASH') {
3457 for my $as (sort keys %$c) {
3458 push @sel, $c->{$as};
3469 # when trying to weed off duplicates later do not go past this point -
3470 # everything added from here on is unbalanced "anyone's guess" stuff
3471 my $dedup_stop_idx = $#as;
3473 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3475 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3476 if $attrs->{select};
3478 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3479 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3481 # disqualify all $alias.col as-bits (inflate-map mandated)
3482 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3484 # de-duplicate the result (remove *identical* select/as pairs)
3485 # and also die on duplicate {as} pointing to different {select}s
3486 # not using a c-style for as the condition is prone to shrinkage
3489 while ($i <= $dedup_stop_idx) {
3490 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3495 elsif ($seen->{$as[$i]}++) {
3496 $self->throw_exception(
3497 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3505 $attrs->{select} = \@sel;
3506 $attrs->{as} = \@as;
3508 $attrs->{from} ||= [{
3510 -alias => $self->{attrs}{alias},
3511 $self->{attrs}{alias} => $source->from,
3514 if ( $attrs->{join} || $attrs->{prefetch} ) {
3516 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3517 if ref $attrs->{from} ne 'ARRAY';
3519 my $join = (delete $attrs->{join}) || {};
3521 if ( defined $attrs->{prefetch} ) {
3522 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3525 $attrs->{from} = # have to copy here to avoid corrupting the original
3527 @{ $attrs->{from} },
3528 $source->_resolve_join(
3531 { %{ $attrs->{seen_join} || {} } },
3532 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3533 ? $attrs->{from}[-1][0]{-join_path}
3540 if ( defined $attrs->{order_by} ) {
3541 $attrs->{order_by} = (
3542 ref( $attrs->{order_by} ) eq 'ARRAY'
3543 ? [ @{ $attrs->{order_by} } ]
3544 : [ $attrs->{order_by} || () ]
3548 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3549 $attrs->{group_by} = [ $attrs->{group_by} ];
3552 # generate the distinct induced group_by early, as prefetch will be carried via a
3553 # subquery (since a group_by is present)
3554 if (delete $attrs->{distinct}) {
3555 if ($attrs->{group_by}) {
3556 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3559 $attrs->{_grouped_by_distinct} = 1;
3560 # distinct affects only the main selection part, not what prefetch may
3562 $attrs->{group_by} = $source->storage->_group_over_selection($attrs);
3566 # generate selections based on the prefetch helper
3568 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3569 if defined $attrs->{prefetch};
3573 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3574 if $attrs->{_dark_selector};
3576 $attrs->{collapse} = 1;
3578 # this is a separate structure (we don't look in {from} directly)
3579 # as the resolver needs to shift things off the lists to work
3580 # properly (identical-prefetches on different branches)
3582 if (ref $attrs->{from} eq 'ARRAY') {
3584 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3586 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3587 next unless $j->[0]{-alias};
3588 next unless $j->[0]{-join_path};
3589 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3591 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3594 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3595 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3599 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3601 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3602 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3605 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3606 $attrs->{_related_results_construction} = 1;
3609 # run through the resulting joinstructure (starting from our current slot)
3610 # and unset collapse if proven unnecessary
3612 # also while we are at it find out if the current root source has
3613 # been premultiplied by previous related_source chaining
3615 # this allows to predict whether a root object with all other relation
3616 # data set to NULL is in fact unique
3617 if ($attrs->{collapse}) {
3619 if (ref $attrs->{from} eq 'ARRAY') {
3621 if (@{$attrs->{from}} == 1) {
3622 # no joins - no collapse
3623 $attrs->{collapse} = 0;
3626 # find where our table-spec starts
3627 my @fromlist = @{$attrs->{from}};
3629 my $t = shift @fromlist;
3632 # me vs join from-spec distinction - a ref means non-root
3633 if (ref $t eq 'ARRAY') {
3635 $is_multi ||= ! $t->{-is_single};
3637 last if ($t->{-alias} && $t->{-alias} eq $alias);
3638 $attrs->{_main_source_premultiplied} ||= $is_multi;
3641 # no non-singles remaining, nor any premultiplication - nothing to collapse
3643 ! $attrs->{_main_source_premultiplied}
3645 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3647 $attrs->{collapse} = 0;
3653 # if we can not analyze the from - err on the side of safety
3654 $attrs->{_main_source_premultiplied} = 1;
3658 # if both page and offset are specified, produce a combined offset
3659 # even though it doesn't make much sense, this is what pre 081xx has
3661 if (my $page = delete $attrs->{page}) {
3663 ($attrs->{rows} * ($page - 1))
3665 ($attrs->{offset} || 0)
3669 return $self->{_attrs} = $attrs;
3673 my ($self, $attr) = @_;
3675 if (ref $attr eq 'HASH') {
3676 return $self->_rollout_hash($attr);
3677 } elsif (ref $attr eq 'ARRAY') {
3678 return $self->_rollout_array($attr);
3684 sub _rollout_array {
3685 my ($self, $attr) = @_;
3688 foreach my $element (@{$attr}) {
3689 if (ref $element eq 'HASH') {
3690 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3691 } elsif (ref $element eq 'ARRAY') {
3692 # XXX - should probably recurse here
3693 push( @rolled_array, @{$self->_rollout_array($element)} );
3695 push( @rolled_array, $element );
3698 return \@rolled_array;
3702 my ($self, $attr) = @_;
3705 foreach my $key (keys %{$attr}) {
3706 push( @rolled_array, { $key => $attr->{$key} } );
3708 return \@rolled_array;
3711 sub _calculate_score {
3712 my ($self, $a, $b) = @_;
3714 if (defined $a xor defined $b) {
3717 elsif (not defined $a) {
3721 if (ref $b eq 'HASH') {
3722 my ($b_key) = keys %{$b};
3723 if (ref $a eq 'HASH') {
3724 my ($a_key) = keys %{$a};
3725 if ($a_key eq $b_key) {
3726 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3731 return ($a eq $b_key) ? 1 : 0;
3734 if (ref $a eq 'HASH') {
3735 my ($a_key) = keys %{$a};
3736 return ($b eq $a_key) ? 1 : 0;
3738 return ($b eq $a) ? 1 : 0;
3743 sub _merge_joinpref_attr {
3744 my ($self, $orig, $import) = @_;
3746 return $import unless defined($orig);
3747 return $orig unless defined($import);
3749 $orig = $self->_rollout_attr($orig);
3750 $import = $self->_rollout_attr($import);
3753 foreach my $import_element ( @{$import} ) {
3754 # find best candidate from $orig to merge $b_element into
3755 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3756 foreach my $orig_element ( @{$orig} ) {
3757 my $score = $self->_calculate_score( $orig_element, $import_element );
3758 if ($score > $best_candidate->{score}) {
3759 $best_candidate->{position} = $position;
3760 $best_candidate->{score} = $score;
3764 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3765 $import_key = '' if not defined $import_key;
3767 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3768 push( @{$orig}, $import_element );
3770 my $orig_best = $orig->[$best_candidate->{position}];
3771 # merge orig_best and b_element together and replace original with merged
3772 if (ref $orig_best ne 'HASH') {
3773 $orig->[$best_candidate->{position}] = $import_element;
3774 } elsif (ref $import_element eq 'HASH') {
3775 my ($key) = keys %{$orig_best};
3776 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3779 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3782 return @$orig ? $orig : ();
3790 require Hash::Merge;
3791 my $hm = Hash::Merge->new;
3793 $hm->specify_behavior({
3796 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3798 if ($defl xor $defr) {
3799 return [ $defl ? $_[0] : $_[1] ];
3804 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3808 return [$_[0], $_[1]];
3812 return $_[1] if !defined $_[0];
3813 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3814 return [$_[0], @{$_[1]}]
3817 return [] if !defined $_[0] and !keys %{$_[1]};
3818 return [ $_[1] ] if !defined $_[0];
3819 return [ $_[0] ] if !keys %{$_[1]};
3820 return [$_[0], $_[1]]
3825 return $_[0] if !defined $_[1];
3826 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3827 return [@{$_[0]}, $_[1]]
3830 my @ret = @{$_[0]} or return $_[1];
3831 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3832 my %idx = map { $_ => 1 } @ret;
3833 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3837 return [ $_[1] ] if ! @{$_[0]};
3838 return $_[0] if !keys %{$_[1]};
3839 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3840 return [ @{$_[0]}, $_[1] ];
3845 return [] if !keys %{$_[0]} and !defined $_[1];
3846 return [ $_[0] ] if !defined $_[1];
3847 return [ $_[1] ] if !keys %{$_[0]};
3848 return [$_[0], $_[1]]
3851 return [] if !keys %{$_[0]} and !@{$_[1]};
3852 return [ $_[0] ] if !@{$_[1]};
3853 return $_[1] if !keys %{$_[0]};
3854 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3855 return [ $_[0], @{$_[1]} ];
3858 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3859 return [ $_[0] ] if !keys %{$_[1]};
3860 return [ $_[1] ] if !keys %{$_[0]};
3861 return [ $_[0] ] if $_[0] eq $_[1];
3862 return [ $_[0], $_[1] ];
3865 } => 'DBIC_RS_ATTR_MERGER');
3869 return $hm->merge ($_[1], $_[2]);
3873 sub STORABLE_freeze {
3874 my ($self, $cloning) = @_;
3875 my $to_serialize = { %$self };
3877 # A cursor in progress can't be serialized (and would make little sense anyway)
3878 # the parser can be regenerated (and can't be serialized)
3879 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3881 # nor is it sensical to store a not-yet-fired-count pager
3882 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3883 delete $to_serialize->{pager};
3886 Storable::nfreeze($to_serialize);
3889 # need this hook for symmetry
3891 my ($self, $cloning, $serialized) = @_;
3893 %$self = %{ Storable::thaw($serialized) };
3899 =head2 throw_exception
3901 See L<DBIx::Class::Schema/throw_exception> for details.
3905 sub throw_exception {
3908 if (ref $self and my $rsrc = $self->result_source) {
3909 $rsrc->throw_exception(@_)
3912 DBIx::Class::Exception->throw(@_);
3920 # XXX: FIXME: Attributes docs need clearing up
3924 Attributes are used to refine a ResultSet in various ways when
3925 searching for data. They can be passed to any method which takes an
3926 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3929 Default attributes can be set on the result class using
3930 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3931 the CAVEATS on that feature before using it!)
3933 These are in no particular order:
3939 =item Value: ( $order_by | \@order_by | \%order_by )
3943 Which column(s) to order the results by.
3945 [The full list of suitable values is documented in
3946 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3949 If a single column name, or an arrayref of names is supplied, the
3950 argument is passed through directly to SQL. The hashref syntax allows
3951 for connection-agnostic specification of ordering direction:
3953 For descending order:
3955 order_by => { -desc => [qw/col1 col2 col3/] }
3957 For explicit ascending order:
3959 order_by => { -asc => 'col' }
3961 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3962 supported, although you are strongly encouraged to use the hashref
3963 syntax as outlined above.
3969 =item Value: \@columns | \%columns | $column
3973 Shortcut to request a particular set of columns to be retrieved. Each
3974 column spec may be a string (a table column name), or a hash (in which
3975 case the key is the C<as> value, and the value is used as the C<select>
3976 expression). Adds C<me.> onto the start of any column without a C<.> in
3977 it and sets C<select> from that, then auto-populates C<as> from
3978 C<select> as normal. (You may also use the C<cols> attribute, as in
3979 earlier versions of DBIC, but this is deprecated.)
3981 Essentially C<columns> does the same as L</select> and L</as>.
3983 columns => [ 'foo', { bar => 'baz' } ]
3987 select => [qw/foo baz/],
3994 =item Value: \@columns
3998 Indicates additional columns to be selected from storage. Works the same as
3999 L</columns> but adds columns to the selection. (You may also use the
4000 C<include_columns> attribute, as in earlier versions of DBIC, but this is
4001 deprecated). For example:-
4003 $schema->resultset('CD')->search(undef, {
4004 '+columns' => ['artist.name'],
4008 would return all CDs and include a 'name' column to the information
4009 passed to object inflation. Note that the 'artist' is the name of the
4010 column (or relationship) accessor, and 'name' is the name of the column
4011 accessor in the related table.
4013 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
4014 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
4015 unary plus operator before it.
4017 =head2 include_columns
4021 =item Value: \@columns
4025 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
4031 =item Value: \@select_columns
4035 Indicates which columns should be selected from the storage. You can use
4036 column names, or in the case of RDBMS back ends, function or stored procedure
4039 $rs = $schema->resultset('Employee')->search(undef, {
4042 { count => 'employeeid' },
4043 { max => { length => 'name' }, -as => 'longest_name' }
4048 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
4050 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
4051 use L</select>, to instruct DBIx::Class how to store the result of the column.
4052 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
4053 identifier aliasing. You can however alias a function, so you can use it in
4054 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
4055 attribute> supplied as shown in the example above.
4057 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
4058 Not doing so causes Perl to incorrectly interpret them as a bareword with a
4059 unary plus operator before it.
4065 Indicates additional columns to be selected from storage. Works the same as
4066 L</select> but adds columns to the default selection, instead of specifying
4075 =item Value: \@inflation_names
4079 Indicates column names for object inflation. That is L</as> indicates the
4080 slot name in which the column value will be stored within the
4081 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4082 identifier by the C<get_column> method (or via the object accessor B<if one
4083 with the same name already exists>) as shown below. The L</as> attribute has
4084 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4086 $rs = $schema->resultset('Employee')->search(undef, {
4089 { count => 'employeeid' },
4090 { max => { length => 'name' }, -as => 'longest_name' }
4099 If the object against which the search is performed already has an accessor
4100 matching a column name specified in C<as>, the value can be retrieved using
4101 the accessor as normal:
4103 my $name = $employee->name();
4105 If on the other hand an accessor does not exist in the object, you need to
4106 use C<get_column> instead:
4108 my $employee_count = $employee->get_column('employee_count');
4110 You can create your own accessors if required - see
4111 L<DBIx::Class::Manual::Cookbook> for details.
4117 Indicates additional column names for those added via L</+select>. See L</as>.
4125 =item Value: ($rel_name | \@rel_names | \%rel_names)
4129 Contains a list of relationships that should be joined for this query. For
4132 # Get CDs by Nine Inch Nails
4133 my $rs = $schema->resultset('CD')->search(
4134 { 'artist.name' => 'Nine Inch Nails' },
4135 { join => 'artist' }
4138 Can also contain a hash reference to refer to the other relation's relations.
4141 package MyApp::Schema::Track;
4142 use base qw/DBIx::Class/;
4143 __PACKAGE__->table('track');
4144 __PACKAGE__->add_columns(qw/trackid cd position title/);
4145 __PACKAGE__->set_primary_key('trackid');
4146 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4149 # In your application
4150 my $rs = $schema->resultset('Artist')->search(
4151 { 'track.title' => 'Teardrop' },
4153 join => { cd => 'track' },
4154 order_by => 'artist.name',
4158 You need to use the relationship (not the table) name in conditions,
4159 because they are aliased as such. The current table is aliased as "me", so
4160 you need to use me.column_name in order to avoid ambiguity. For example:
4162 # Get CDs from 1984 with a 'Foo' track
4163 my $rs = $schema->resultset('CD')->search(
4166 'tracks.name' => 'Foo'
4168 { join => 'tracks' }
4171 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4172 similarly for a third time). For e.g.
4174 my $rs = $schema->resultset('Artist')->search({
4175 'cds.title' => 'Down to Earth',
4176 'cds_2.title' => 'Popular',
4178 join => [ qw/cds cds/ ],
4181 will return a set of all artists that have both a cd with title 'Down
4182 to Earth' and a cd with title 'Popular'.
4184 If you want to fetch related objects from other tables as well, see L</prefetch>
4187 NOTE: An internal join-chain pruner will discard certain joins while
4188 constructing the actual SQL query, as long as the joins in question do not
4189 affect the retrieved result. This for example includes 1:1 left joins
4190 that are not part of the restriction specification (WHERE/HAVING) nor are
4191 a part of the query selection.
4193 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4199 =item Value: (0 | 1)
4203 When set to a true value, indicates that any rows fetched from joined has_many
4204 relationships are to be aggregated into the corresponding "parent" object. For
4205 example, the resultset:
4207 my $rs = $schema->resultset('CD')->search({}, {
4208 '+columns' => [ qw/ tracks.title tracks.position / ],
4213 While executing the following query:
4215 SELECT me.*, tracks.title, tracks.position
4217 LEFT JOIN track tracks
4218 ON tracks.cdid = me.cdid
4220 Will return only as many objects as there are rows in the CD source, even
4221 though the result of the query may span many rows. Each of these CD objects
4222 will in turn have multiple "Track" objects hidden behind the has_many
4223 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4224 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4225 product"), with each CD object containing exactly one of all fetched Track data.
4227 When a collapse is requested on a non-ordered resultset, an order by some
4228 unique part of the main source (the left-most table) is inserted automatically.
4229 This is done so that the resultset is allowed to be "lazy" - calling
4230 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4231 object with all of its related data.
4233 If an L</order_by> is already declared, and orders the resultset in a way that
4234 makes collapsing as described above impossible (e.g. C<< ORDER BY
4235 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4236 switch to "eager" mode and slurp the entire resultset before constructing the
4237 first object returned by L</next>.
4239 Setting this attribute on a resultset that does not join any has_many
4240 relations is a no-op.
4242 For a more in-depth discussion, see L</PREFETCHING>.
4248 =item Value: ($rel_name | \@rel_names | \%rel_names)
4252 This attribute is a shorthand for specifying a L</join> spec, adding all
4253 columns from the joined related sources as L</+columns> and setting
4254 L</collapse> to a true value. For example, the following two queries are
4257 my $rs = $schema->resultset('Artist')->search({}, {
4258 prefetch => { cds => ['genre', 'tracks' ] },
4263 my $rs = $schema->resultset('Artist')->search({}, {
4264 join => { cds => ['genre', 'tracks' ] },
4268 { +{ "cds.$_" => "cds.$_" } }
4269 $schema->source('Artist')->related_source('cds')->columns
4272 { +{ "cds.genre.$_" => "genre.$_" } }
4273 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4276 { +{ "cds.tracks.$_" => "tracks.$_" } }
4277 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4282 Both producing the following SQL:
4284 SELECT me.artistid, me.name, me.rank, me.charfield,
4285 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4286 genre.genreid, genre.name,
4287 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4290 ON cds.artist = me.artistid
4291 LEFT JOIN genre genre
4292 ON genre.genreid = cds.genreid
4293 LEFT JOIN track tracks
4294 ON tracks.cd = cds.cdid
4295 ORDER BY me.artistid
4297 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4298 the arguments are properly merged and generally do the right thing. For
4299 example, you may want to do the following:
4301 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4302 { 'genre.genreid' => undef },
4304 join => { cds => 'genre' },
4309 Which generates the following SQL:
4311 SELECT me.artistid, me.name, me.rank, me.charfield,
4312 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4315 ON cds.artist = me.artistid
4316 LEFT JOIN genre genre
4317 ON genre.genreid = cds.genreid
4318 WHERE genre.genreid IS NULL
4319 ORDER BY me.artistid
4321 For a more in-depth discussion, see L</PREFETCHING>.
4327 =item Value: $source_alias
4331 Sets the source alias for the query. Normally, this defaults to C<me>, but
4332 nested search queries (sub-SELECTs) might need specific aliases set to
4333 reference inner queries. For example:
4336 ->related_resultset('CDs')
4337 ->related_resultset('Tracks')
4339 'track.id' => { -ident => 'none_search.id' },
4343 my $ids = $self->search({
4346 alias => 'none_search',
4347 group_by => 'none_search.id',
4348 })->get_column('id')->as_query;
4350 $self->search({ id => { -in => $ids } })
4352 This attribute is directly tied to L</current_source_alias>.
4362 Makes the resultset paged and specifies the page to retrieve. Effectively
4363 identical to creating a non-pages resultset and then calling ->page($page)
4366 If L</rows> attribute is not specified it defaults to 10 rows per page.
4368 When you have a paged resultset, L</count> will only return the number
4369 of rows in the page. To get the total, use the L</pager> and call
4370 C<total_entries> on it.
4380 Specifies the maximum number of rows for direct retrieval or the number of
4381 rows per page if the page attribute or method is used.
4387 =item Value: $offset
4391 Specifies the (zero-based) row number for the first row to be returned, or the
4392 of the first row of the first page if paging is used.
4394 =head2 software_limit
4398 =item Value: (0 | 1)
4402 When combined with L</rows> and/or L</offset> the generated SQL will not
4403 include any limit dialect stanzas. Instead the entire result will be selected
4404 as if no limits were specified, and DBIC will perform the limit locally, by
4405 artificially advancing and finishing the resulting L</cursor>.
4407 This is the recommended way of performing resultset limiting when no sane RDBMS
4408 implementation is available (e.g.
4409 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4410 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4416 =item Value: \@columns
4420 A arrayref of columns to group by. Can include columns of joined tables.
4422 group_by => [qw/ column1 column2 ... /]
4428 =item Value: $condition
4432 HAVING is a select statement attribute that is applied between GROUP BY and
4433 ORDER BY. It is applied to the after the grouping calculations have been
4436 having => { 'count_employee' => { '>=', 100 } }
4438 or with an in-place function in which case literal SQL is required:
4440 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4446 =item Value: (0 | 1)
4450 Set to 1 to group by all columns. If the resultset already has a group_by
4451 attribute, this setting is ignored and an appropriate warning is issued.
4457 Adds to the WHERE clause.
4459 # only return rows WHERE deleted IS NULL for all searches
4460 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4462 Can be overridden by passing C<< { where => undef } >> as an attribute
4465 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4471 Set to 1 to cache search results. This prevents extra SQL queries if you
4472 revisit rows in your ResultSet:
4474 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4476 while( my $artist = $resultset->next ) {
4480 $rs->first; # without cache, this would issue a query
4482 By default, searches are not cached.
4484 For more examples of using these attributes, see
4485 L<DBIx::Class::Manual::Cookbook>.
4491 =item Value: ( 'update' | 'shared' | \$scalar )
4495 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4496 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4501 DBIx::Class supports arbitrary related data prefetching from multiple related
4502 sources. Any combination of relationship types and column sets are supported.
4503 If L<collapsing|/collapse> is requested, there is an additional requirement of
4504 selecting enough data to make every individual object uniquely identifiable.
4506 Here are some more involved examples, based on the following relationship map:
4509 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4510 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4511 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4513 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4515 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4519 my $rs = $schema->resultset('Tag')->search(
4528 The initial search results in SQL like the following:
4530 SELECT tag.*, cd.*, artist.* FROM tag
4531 JOIN cd ON tag.cd = cd.cdid
4532 JOIN artist ON cd.artist = artist.artistid
4534 L<DBIx::Class> has no need to go back to the database when we access the
4535 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4538 Simple prefetches will be joined automatically, so there is no need
4539 for a C<join> attribute in the above search.
4541 The L</prefetch> attribute can be used with any of the relationship types
4542 and multiple prefetches can be specified together. Below is a more complex
4543 example that prefetches a CD's artist, its liner notes (if present),
4544 the cover image, the tracks on that CD, and the guests on those
4547 my $rs = $schema->resultset('CD')->search(
4551 { artist => 'record_label'}, # belongs_to => belongs_to
4552 'liner_note', # might_have
4553 'cover_image', # has_one
4554 { tracks => 'guests' }, # has_many => has_many
4559 This will produce SQL like the following:
4561 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4565 ON artist.artistid = me.artistid
4566 JOIN record_label record_label
4567 ON record_label.labelid = artist.labelid
4568 LEFT JOIN track tracks
4569 ON tracks.cdid = me.cdid
4570 LEFT JOIN guest guests
4571 ON guests.trackid = track.trackid
4572 LEFT JOIN liner_notes liner_note
4573 ON liner_note.cdid = me.cdid
4574 JOIN cd_artwork cover_image
4575 ON cover_image.cdid = me.cdid
4578 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4579 C<tracks>, and C<guests> of the CD will all be available through the
4580 relationship accessors without the need for additional queries to the
4585 Prefetch does a lot of deep magic. As such, it may not behave exactly
4586 as you might expect.
4592 Prefetch uses the L</cache> to populate the prefetched relationships. This
4593 may or may not be what you want.
4597 If you specify a condition on a prefetched relationship, ONLY those
4598 rows that match the prefetched condition will be fetched into that relationship.
4599 This means that adding prefetch to a search() B<may alter> what is returned by
4600 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4602 my $artist_rs = $schema->resultset('Artist')->search({
4608 my $count = $artist_rs->first->cds->count;
4610 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4612 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4614 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4616 That cmp_ok() may or may not pass depending on the datasets involved. In other
4617 words the C<WHERE> condition would apply to the entire dataset, just like
4618 it would in regular SQL. If you want to add a condition only to the "right side"
4619 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4620 condition|DBIx::Class::Relationship::Base/condition>
4624 =head1 DBIC BIND VALUES
4626 Because DBIC may need more information to bind values than just the column name
4627 and value itself, it uses a special format for both passing and receiving bind
4628 values. Each bind value should be composed of an arrayref of
4629 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4635 If present (in any form), this is what is being passed directly to bind_param.
4636 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4637 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4639 If this is specified, all other bind options described below are ignored.
4643 If present, this is used to infer the actual bind attribute by passing to
4644 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4645 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4647 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4648 currently drivers are expected to "Do the Right Thing" when given a common
4649 datatype name. (Not ideal, but that's what we got at this point.)
4653 Currently used to correctly allocate buffers for bind_param_inout().
4654 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4655 or to a sensible value based on the "data_type".
4659 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4660 explicitly specified they are never overridden). Also used by some weird DBDs,
4661 where the column name should be available at bind_param time (e.g. Oracle).
4665 For backwards compatibility and convenience, the following shortcuts are
4668 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4669 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4670 [ undef, $val ] === [ {}, $val ]
4671 $val === [ {}, $val ]
4673 =head1 AUTHOR AND CONTRIBUTORS
4675 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4679 You may distribute this code under the same terms as Perl itself.