1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::ResultSetColumn;
8 use Scalar::Util qw/blessed weaken reftype/;
9 use DBIx::Class::_Util qw(
10 fail_on_internal_wantarray is_plain_value is_literal_value
13 use Data::Compare (); # no imports!!! guard against insane architecture
15 # not importing first() as it will clash with our own method
19 # De-duplication in _merge_attr() is disabled, but left in for reference
20 # (the merger is used for other things that ought not to be de-duped)
21 *__HM_DEDUP = sub () { 0 };
31 # this is real - CDBICompat overrides it with insanity
32 # yes, prototype won't matter, but that's for now ;)
35 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
39 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
43 my $users_rs = $schema->resultset('User');
44 while( $user = $users_rs->next) {
45 print $user->username;
48 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
49 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
53 A ResultSet is an object which stores a set of conditions representing
54 a query. It is the backbone of DBIx::Class (i.e. the really
55 important/useful bit).
57 No SQL is executed on the database when a ResultSet is created, it
58 just stores all the conditions needed to create the query.
60 A basic ResultSet representing the data of an entire table is returned
61 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
62 L<Source|DBIx::Class::Manual::Glossary/Source> name.
64 my $users_rs = $schema->resultset('User');
66 A new ResultSet is returned from calling L</search> on an existing
67 ResultSet. The new one will contain all the conditions of the
68 original, plus any new conditions added in the C<search> call.
70 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
71 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
74 The query that the ResultSet represents is B<only> executed against
75 the database when these methods are called:
76 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
78 If a resultset is used in a numeric context it returns the L</count>.
79 However, if it is used in a boolean context it is B<always> true. So if
80 you want to check if a resultset has any results, you must use C<if $rs
83 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
85 If you want to make your custom ResultSet classes with L<Moose>, use a template
88 package MyApp::Schema::ResultSet::User;
91 use namespace::autoclean;
93 extends 'DBIx::Class::ResultSet';
95 sub BUILDARGS { $_[2] }
99 __PACKAGE__->meta->make_immutable;
103 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
104 clash with the regular ResultSet constructor. Alternatively, you can use:
106 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
108 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
109 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
113 =head2 Chaining resultsets
115 Let's say you've got a query that needs to be run to return some data
116 to the user. But, you have an authorization system in place that
117 prevents certain users from seeing certain information. So, you want
118 to construct the basic query in one method, but add constraints to it in
123 my $request = $self->get_request; # Get a request object somehow.
124 my $schema = $self->result_source->schema;
126 my $cd_rs = $schema->resultset('CD')->search({
127 title => $request->param('title'),
128 year => $request->param('year'),
131 $cd_rs = $self->apply_security_policy( $cd_rs );
133 return $cd_rs->all();
136 sub apply_security_policy {
145 =head3 Resolving conditions and attributes
147 When a resultset is chained from another resultset (e.g.:
148 C<< my $new_rs = $old_rs->search(\%extra_cond, \%attrs) >>), conditions
149 and attributes with the same keys need resolving.
151 If any of L</columns>, L</select>, L</as> are present, they reset the
152 original selection, and start the selection "clean".
154 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
155 are merged into the existing ones from the original resultset.
157 The L</where> and L</having> attributes, and any search conditions, are
158 merged with an SQL C<AND> to the existing condition from the original
161 All other attributes are overridden by any new ones supplied in the
164 =head2 Multiple queries
166 Since a resultset just defines a query, you can do all sorts of
167 things with it with the same object.
169 # Don't hit the DB yet.
170 my $cd_rs = $schema->resultset('CD')->search({
171 title => 'something',
175 # Each of these hits the DB individually.
176 my $count = $cd_rs->count;
177 my $most_recent = $cd_rs->get_column('date_released')->max();
178 my @records = $cd_rs->all;
180 And it's not just limited to SELECT statements.
186 $cd_rs->create({ artist => 'Fred' });
188 Which is the same as:
190 $schema->resultset('CD')->create({
191 title => 'something',
196 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
204 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
206 =item Return Value: L<$resultset|/search>
210 The resultset constructor. Takes a source object (usually a
211 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
212 L</ATTRIBUTES> below). Does not perform any queries -- these are
213 executed as needed by the other methods.
215 Generally you never construct a resultset manually. Instead you get one
217 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
218 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
221 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
227 If called on an object, proxies to L</new_result> instead, so
229 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
231 will return a CD object, not a ResultSet, and is equivalent to:
233 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
235 Please also keep in mind that many internals call L</new_result> directly,
236 so overloading this method with the idea of intercepting new result object
237 creation B<will not work>. See also warning pertaining to L</create>.
245 return $class->new_result(@_) if ref $class;
247 my ($source, $attrs) = @_;
248 $source = $source->resolve
249 if $source->isa('DBIx::Class::ResultSourceHandle');
251 $attrs = { %{$attrs||{}} };
252 delete @{$attrs}{qw(_last_sqlmaker_alias_map _related_results_construction)};
254 if ($attrs->{page}) {
255 $attrs->{rows} ||= 10;
258 $attrs->{alias} ||= 'me';
261 result_source => $source,
262 cond => $attrs->{where},
267 # if there is a dark selector, this means we are already in a
268 # chain and the cleanup/sanification was taken care of by
270 $self->_normalize_selection($attrs)
271 unless $attrs->{_dark_selector};
274 $attrs->{result_class} || $source->result_class
284 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
286 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
290 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
291 my $new_rs = $cd_rs->search({ year => 2005 });
293 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
294 # year = 2005 OR year = 2004
296 In list context, C<< ->all() >> is called implicitly on the resultset, thus
297 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
298 To avoid that, use L</search_rs>.
300 If you need to pass in additional attributes but no additional condition,
301 call it as C<search(undef, \%attrs)>.
303 # "SELECT name, artistid FROM $artist_table"
304 my @all_artists = $schema->resultset('Artist')->search(undef, {
305 columns => [qw/name artistid/],
308 For a list of attributes that can be passed to C<search>, see
309 L</ATTRIBUTES>. For more examples of using this function, see
310 L<Searching|DBIx::Class::Manual::Cookbook/SEARCHING>. For a complete
311 documentation for the first argument, see L<SQL::Abstract/"WHERE CLAUSES">
312 and its extension L<DBIx::Class::SQLMaker>.
314 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
318 Note that L</search> does not process/deflate any of the values passed in the
319 L<SQL::Abstract>-compatible search condition structure. This is unlike other
320 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
321 manually that any value passed to this method will stringify to something the
322 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
323 objects, for more info see:
324 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
330 my $rs = $self->search_rs( @_ );
333 DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_WANTARRAY and my $sog = fail_on_internal_wantarray($rs);
336 elsif (defined wantarray) {
340 # we can be called by a relationship helper, which in
341 # turn may be called in void context due to some braindead
342 # overload or whatever else the user decided to be clever
343 # at this particular day. Thus limit the exception to
344 # external code calls only
345 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
346 if (caller)[0] !~ /^\QDBIx::Class::/;
356 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
358 =item Return Value: L<$resultset|/search>
362 This method does the same exact thing as search() except it will
363 always return a resultset, even in list context.
370 my $rsrc = $self->result_source;
371 my ($call_cond, $call_attrs);
373 # Special-case handling for (undef, undef) or (undef)
374 # Note that (foo => undef) is valid deprecated syntax
375 @_ = () if not scalar grep { defined $_ } @_;
381 # fish out attrs in the ($condref, $attr) case
382 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
383 ($call_cond, $call_attrs) = @_;
386 $self->throw_exception('Odd number of arguments to search')
390 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
391 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
393 for my $i (0 .. $#_) {
395 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
396 if (! defined $_[$i] or ref $_[$i] ne '');
402 # see if we can keep the cache (no $rs changes)
404 my %safe = (alias => 1, cache => 1);
405 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
408 ref $call_cond eq 'HASH' && ! keys %$call_cond
410 ref $call_cond eq 'ARRAY' && ! @$call_cond
412 $cache = $self->get_cache;
415 my $old_attrs = { %{$self->{attrs}} };
416 my ($old_having, $old_where) = delete @{$old_attrs}{qw(having where)};
418 my $new_attrs = { %$old_attrs };
420 # take care of call attrs (only if anything is changing)
421 if ($call_attrs and keys %$call_attrs) {
423 # copy for _normalize_selection
424 $call_attrs = { %$call_attrs };
426 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
428 # reset the current selector list if new selectors are supplied
429 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
430 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
433 # Normalize the new selector list (operates on the passed-in attr structure)
434 # Need to do it on every chain instead of only once on _resolved_attrs, in
435 # order to allow detection of empty vs partial 'as'
436 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
437 if $old_attrs->{_dark_selector};
438 $self->_normalize_selection ($call_attrs);
440 # start with blind overwriting merge, exclude selector attrs
441 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
442 delete @{$new_attrs}{@selector_attrs};
444 for (@selector_attrs) {
445 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
446 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
449 # older deprecated name, use only if {columns} is not there
450 if (my $c = delete $new_attrs->{cols}) {
451 carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
452 if ($new_attrs->{columns}) {
453 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
456 $new_attrs->{columns} = $c;
461 # join/prefetch use their own crazy merging heuristics
462 foreach my $key (qw/join prefetch/) {
463 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
464 if exists $call_attrs->{$key};
467 # stack binds together
468 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
472 for ($old_where, $call_cond) {
474 $new_attrs->{where} = $self->_stack_cond (
475 $_, $new_attrs->{where}
480 if (defined $old_having) {
481 $new_attrs->{having} = $self->_stack_cond (
482 $old_having, $new_attrs->{having}
486 my $rs = (ref $self)->new($rsrc, $new_attrs);
488 $rs->set_cache($cache) if ($cache);
494 sub _normalize_selection {
495 my ($self, $attrs) = @_;
498 if ( exists $attrs->{include_columns} ) {
499 carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
500 $attrs->{'+columns'} = $self->_merge_attr(
501 $attrs->{'+columns'}, delete $attrs->{include_columns}
505 # columns are always placed first, however
507 # Keep the X vs +X separation until _resolved_attrs time - this allows to
508 # delay the decision on whether to use a default select list ($rsrc->columns)
509 # allowing stuff like the remove_columns helper to work
511 # select/as +select/+as pairs need special handling - the amount of select/as
512 # elements in each pair does *not* have to be equal (think multicolumn
513 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
514 # supplied at all) - try to infer the alias, either from the -as parameter
515 # of the selector spec, or use the parameter whole if it looks like a column
516 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
517 # is ok as well), but make sure no more additions to the 'as' chain take place
518 for my $pref ('', '+') {
520 my ($sel, $as) = map {
521 my $key = "${pref}${_}";
523 my $val = [ ref $attrs->{$key} eq 'ARRAY'
525 : $attrs->{$key} || ()
527 delete $attrs->{$key};
531 if (! @$as and ! @$sel ) {
534 elsif (@$as and ! @$sel) {
535 $self->throw_exception(
536 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
540 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
541 # if any @$as has been supplied we assume the user knows what (s)he is doing
542 # and blindly keep stacking up pieces
543 unless ($attrs->{_dark_selector}) {
546 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
547 push @$as, $_->{-as};
549 # assume any plain no-space, no-parenthesis string to be a column spec
550 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
551 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
554 # if all else fails - raise a flag that no more aliasing will be allowed
556 $attrs->{_dark_selector} = {
558 string => ($dark_sel_dumper ||= do {
559 require Data::Dumper::Concise;
560 Data::Dumper::Concise::DumperObject()->Indent(0);
561 })->Values([$_])->Dump
569 elsif (@$as < @$sel) {
570 $self->throw_exception(
571 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
574 elsif ($pref and $attrs->{_dark_selector}) {
575 $self->throw_exception(
576 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
582 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
583 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
588 my ($self, $left, $right) = @_;
591 (ref $_ eq 'ARRAY' and !@$_)
593 (ref $_ eq 'HASH' and ! keys %$_)
594 ) and $_ = undef for ($left, $right);
596 # either on of the two undef or both undef
597 if ( ( (defined $left) xor (defined $right) ) or ! defined $left ) {
598 return defined $left ? $left : $right;
601 my $cond = $self->result_source->schema->storage->_collapse_cond({ -and => [$left, $right] });
603 for my $c (grep { ref $cond->{$_} eq 'ARRAY' and ($cond->{$_}[0]||'') eq '-and' } keys %$cond) {
605 my @vals = sort @{$cond->{$c}}[ 1..$#{$cond->{$c}} ];
606 my @fin = shift @vals;
609 push @fin, $v unless Data::Compare::Compare( $fin[-1], $v );
612 $cond->{$c} = (@fin == 1) ? $fin[0] : [-and => @fin ];
618 =head2 search_literal
620 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
621 should only be used in that context. C<search_literal> is a convenience
622 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
623 want to ensure columns are bound correctly, use L</search>.
625 See L<DBIx::Class::Manual::Cookbook/SEARCHING> and
626 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
627 require C<search_literal>.
631 =item Arguments: $sql_fragment, @standalone_bind_values
633 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
637 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
638 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
640 Pass a literal chunk of SQL to be added to the conditional part of the
643 Example of how to use C<search> instead of C<search_literal>
645 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
646 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
651 my ($self, $sql, @bind) = @_;
653 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
656 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
663 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
665 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
669 Finds and returns a single row based on supplied criteria. Takes either a
670 hashref with the same format as L</create> (including inference of foreign
671 keys from related objects), or a list of primary key values in the same
672 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
673 declaration on the L</result_source>.
675 In either case an attempt is made to combine conditions already existing on
676 the resultset with the condition passed to this method.
678 To aid with preparing the correct query for the storage you may supply the
679 C<key> attribute, which is the name of a
680 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
681 unique constraint corresponding to the
682 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
683 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
684 to construct a query that satisfies the named unique constraint fully (
685 non-NULL values for each column member of the constraint) an exception is
688 If no C<key> is specified, the search is carried over all unique constraints
689 which are fully defined by the available condition.
691 If no such constraint is found, C<find> currently defaults to a simple
692 C<< search->(\%column_values) >> which may or may not do what you expect.
693 Note that this fallback behavior may be deprecated in further versions. If
694 you need to search with arbitrary conditions - use L</search>. If the query
695 resulting from this fallback produces more than one row, a warning to the
696 effect is issued, though only the first row is constructed and returned as
699 In addition to C<key>, L</find> recognizes and applies standard
700 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
702 Note that if you have extra concerns about the correctness of the resulting
703 query you need to specify the C<key> attribute and supply the entire condition
704 as an argument to find (since it is not always possible to perform the
705 combination of the resultset condition with the supplied one, especially if
706 the resultset condition contains literal sql).
708 For example, to find a row by its primary key:
710 my $cd = $schema->resultset('CD')->find(5);
712 You can also find a row by a specific unique constraint:
714 my $cd = $schema->resultset('CD')->find(
716 artist => 'Massive Attack',
717 title => 'Mezzanine',
719 { key => 'cd_artist_title' }
722 See also L</find_or_create> and L</update_or_create>.
728 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
730 my $rsrc = $self->result_source;
733 if (exists $attrs->{key}) {
734 $constraint_name = defined $attrs->{key}
736 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
740 # Parse out the condition from input
743 if (ref $_[0] eq 'HASH') {
744 $call_cond = { %{$_[0]} };
747 # if only values are supplied we need to default to 'primary'
748 $constraint_name = 'primary' unless defined $constraint_name;
750 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
752 $self->throw_exception(
753 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
756 $self->throw_exception (
757 'find() expects either a column/value hashref, or a list of values '
758 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
759 ) unless @c_cols == @_;
762 @{$call_cond}{@c_cols} = @_;
766 for my $key (keys %$call_cond) {
768 my $keyref = ref($call_cond->{$key})
770 my $relinfo = $rsrc->relationship_info($key)
772 my $val = delete $call_cond->{$key};
774 next if $keyref eq 'ARRAY'; # has_many for multi_create
776 my $rel_q = $rsrc->_resolve_condition(
777 $relinfo->{cond}, $val, $key, $key
779 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
780 @related{keys %$rel_q} = values %$rel_q;
784 # relationship conditions take precedence (?)
785 @{$call_cond}{keys %related} = values %related;
787 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
789 if (defined $constraint_name) {
790 $final_cond = $self->_qualify_cond_columns (
792 $self->_build_unique_cond (
800 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
801 # This means that we got here after a merger of relationship conditions
802 # in ::Relationship::Base::search_related (the row method), and furthermore
803 # the relationship is of the 'single' type. This means that the condition
804 # provided by the relationship (already attached to $self) is sufficient,
805 # as there can be only one row in the database that would satisfy the
809 # no key was specified - fall down to heuristics mode:
810 # run through all unique queries registered on the resultset, and
811 # 'OR' all qualifying queries together
812 my (@unique_queries, %seen_column_combinations);
813 for my $c_name ($rsrc->unique_constraint_names) {
814 next if $seen_column_combinations{
815 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
818 push @unique_queries, try {
819 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
823 $final_cond = @unique_queries
824 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
825 : $self->_non_unique_find_fallback ($call_cond, $attrs)
829 # Run the query, passing the result_class since it should propagate for find
830 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
831 if ($rs->_resolved_attrs->{collapse}) {
833 carp "Query returned more than one row" if $rs->next;
841 # This is a stop-gap method as agreed during the discussion on find() cleanup:
842 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
844 # It is invoked when find() is called in legacy-mode with insufficiently-unique
845 # condition. It is provided for overrides until a saner way forward is devised
847 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
848 # the road. Please adjust your tests accordingly to catch this situation early
849 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
851 # The method will not be removed without an adequately complete replacement
852 # for strict-mode enforcement
853 sub _non_unique_find_fallback {
854 my ($self, $cond, $attrs) = @_;
856 return $self->_qualify_cond_columns(
858 exists $attrs->{alias}
860 : $self->{attrs}{alias}
865 sub _qualify_cond_columns {
866 my ($self, $cond, $alias) = @_;
868 my %aliased = %$cond;
869 for (keys %aliased) {
870 $aliased{"$alias.$_"} = delete $aliased{$_}
877 sub _build_unique_cond {
878 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
880 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
882 # combination may fail if $self->{cond} is non-trivial
883 my ($final_cond) = try {
884 $self->_merge_with_rscond ($extra_cond)
889 # trim out everything not in $columns
890 $final_cond = { map {
891 exists $final_cond->{$_}
892 ? ( $_ => $final_cond->{$_} )
896 if (my @missing = grep
897 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
900 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
902 join (', ', map { "'$_'" } @missing),
909 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
911 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
913 carp_unique ( sprintf (
914 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
915 . 'values in column(s): %s). This is almost certainly not what you wanted, '
916 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
918 join (', ', map { "'$_'" } @undefs),
925 =head2 search_related
929 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
931 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
935 $new_rs = $cd_rs->search_related('artist', {
939 Searches the specified relationship, optionally specifying a condition and
940 attributes for matching records. See L</ATTRIBUTES> for more information.
942 In list context, C<< ->all() >> is called implicitly on the resultset, thus
943 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
945 See also L</search_related_rs>.
950 return shift->related_resultset(shift)->search(@_);
953 =head2 search_related_rs
955 This method works exactly the same as search_related, except that
956 it guarantees a resultset, even in list context.
960 sub search_related_rs {
961 return shift->related_resultset(shift)->search_rs(@_);
968 =item Arguments: none
970 =item Return Value: L<$cursor|DBIx::Class::Cursor>
974 Returns a storage-driven cursor to the given resultset. See
975 L<DBIx::Class::Cursor> for more information.
982 return $self->{cursor} ||= do {
983 my $attrs = $self->_resolved_attrs;
984 $self->result_source->storage->select(
985 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
994 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
996 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1000 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1002 Inflates the first result without creating a cursor if the resultset has
1003 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1006 While this method can take an optional search condition (just like L</search>)
1007 being a fast-code-path it does not recognize search attributes. If you need to
1008 add extra joins or similar, call L</search> and then chain-call L</single> on the
1009 L<DBIx::Class::ResultSet> returned.
1015 As of 0.08100, this method enforces the assumption that the preceding
1016 query returns only one row. If more than one row is returned, you will receive
1019 Query returned more than one row
1021 In this case, you should be using L</next> or L</find> instead, or if you really
1022 know what you are doing, use the L</rows> attribute to explicitly limit the size
1025 This method will also throw an exception if it is called on a resultset prefetching
1026 has_many, as such a prefetch implies fetching multiple rows from the database in
1027 order to assemble the resulting object.
1034 my ($self, $where) = @_;
1036 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1039 my $attrs = { %{$self->_resolved_attrs} };
1041 $self->throw_exception(
1042 'single() can not be used on resultsets collapsing a has_many. Use find( \%cond ) or next() instead'
1043 ) if $attrs->{collapse};
1046 if (defined $attrs->{where}) {
1049 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1050 $where, delete $attrs->{where} ]
1053 $attrs->{where} = $where;
1057 my $data = [ $self->result_source->storage->select_single(
1058 $attrs->{from}, $attrs->{select},
1059 $attrs->{where}, $attrs
1062 return undef unless @$data;
1063 $self->{_stashed_rows} = [ $data ];
1064 $self->_construct_results->[0];
1071 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1073 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1077 my $max_length = $rs->get_column('length')->max;
1079 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1084 my ($self, $column) = @_;
1085 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1093 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1095 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1099 # WHERE title LIKE '%blue%'
1100 $cd_rs = $rs->search_like({ title => '%blue%'});
1102 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1103 that this is simply a convenience method retained for ex Class::DBI users.
1104 You most likely want to use L</search> with specific operators.
1106 For more information, see L<DBIx::Class::Manual::Cookbook>.
1108 This method is deprecated and will be removed in 0.09. Use L</search()>
1109 instead. An example conversion is:
1111 ->search_like({ foo => 'bar' });
1115 ->search({ foo => { like => 'bar' } });
1122 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1123 .' Instead use ->search({ x => { -like => "y%" } })'
1124 .' (note the outer pair of {}s - they are important!)'
1126 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1127 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1128 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1129 return $class->search($query, { %$attrs });
1136 =item Arguments: $first, $last
1138 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1142 Returns a resultset or object list representing a subset of elements from the
1143 resultset slice is called on. Indexes are from 0, i.e., to get the first
1144 three records, call:
1146 my ($one, $two, $three) = $rs->slice(0, 2);
1151 my ($self, $min, $max) = @_;
1152 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1153 $attrs->{offset} = $self->{attrs}{offset} || 0;
1154 $attrs->{offset} += $min;
1155 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1156 return $self->search(undef, $attrs);
1163 =item Arguments: none
1165 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1169 Returns the next element in the resultset (C<undef> is there is none).
1171 Can be used to efficiently iterate over records in the resultset:
1173 my $rs = $schema->resultset('CD')->search;
1174 while (my $cd = $rs->next) {
1178 Note that you need to store the resultset object, and call C<next> on it.
1179 Calling C<< resultset('Table')->next >> repeatedly will always return the
1180 first record from the resultset.
1187 if (my $cache = $self->get_cache) {
1188 $self->{all_cache_position} ||= 0;
1189 return $cache->[$self->{all_cache_position}++];
1192 if ($self->{attrs}{cache}) {
1193 delete $self->{pager};
1194 $self->{all_cache_position} = 1;
1195 return ($self->all)[0];
1198 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1200 $self->{_stashed_results} = $self->_construct_results
1203 return shift @{$self->{_stashed_results}};
1206 # Constructs as many results as it can in one pass while respecting
1207 # cursor laziness. Several modes of operation:
1209 # * Always builds everything present in @{$self->{_stashed_rows}}
1210 # * If called with $fetch_all true - pulls everything off the cursor and
1211 # builds all result structures (or objects) in one pass
1212 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1213 # and if the resultset is ordered properly by the left side:
1214 # * Fetches stuff off the cursor until the "master object" changes,
1215 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1217 # * Just fetches, and collapses/constructs everything as if $fetch_all
1218 # was requested (there is no other way to collapse except for an
1220 # * If no collapse is requested - just get the next row, construct and
1222 sub _construct_results {
1223 my ($self, $fetch_all) = @_;
1225 my $rsrc = $self->result_source;
1226 my $attrs = $self->_resolved_attrs;
1231 ! $attrs->{order_by}
1235 my @pcols = $rsrc->primary_columns
1237 # default order for collapsing unless the user asked for something
1238 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
1239 $attrs->{_ordered_for_collapse} = 1;
1240 $attrs->{_order_is_artificial} = 1;
1243 # this will be used as both initial raw-row collector AND as a RV of
1244 # _construct_results. Not regrowing the array twice matters a lot...
1245 # a surprising amount actually
1246 my $rows = delete $self->{_stashed_rows};
1248 my $cursor; # we may not need one at all
1250 my $did_fetch_all = $fetch_all;
1253 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1254 $rows = [ ($rows ? @$rows : ()), $self->cursor->all ];
1256 elsif( $attrs->{collapse} ) {
1258 # a cursor will need to be closed over in case of collapse
1259 $cursor = $self->cursor;
1261 $attrs->{_ordered_for_collapse} = (
1267 ->_main_source_order_by_portion_is_stable($rsrc, $attrs->{order_by}, $attrs->{where})
1269 ) unless defined $attrs->{_ordered_for_collapse};
1271 if (! $attrs->{_ordered_for_collapse}) {
1274 # instead of looping over ->next, use ->all in stealth mode
1275 # *without* calling a ->reset afterwards
1276 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1277 if (! $cursor->{_done}) {
1278 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1279 $cursor->{_done} = 1;
1284 if (! $did_fetch_all and ! @{$rows||[]} ) {
1285 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1286 $cursor ||= $self->cursor;
1287 if (scalar (my @r = $cursor->next) ) {
1292 return undef unless @{$rows||[]};
1294 # sanity check - people are too clever for their own good
1295 if ($attrs->{collapse} and my $aliastypes = $attrs->{_last_sqlmaker_alias_map} ) {
1297 my $multiplied_selectors;
1298 for my $sel_alias ( grep { $_ ne $attrs->{alias} } keys %{ $aliastypes->{selecting} } ) {
1300 $aliastypes->{multiplying}{$sel_alias}
1302 $aliastypes->{premultiplied}{$sel_alias}
1304 $multiplied_selectors->{$_} = 1 for values %{$aliastypes->{selecting}{$sel_alias}{-seen_columns}}
1308 for my $i (0 .. $#{$attrs->{as}} ) {
1309 my $sel = $attrs->{select}[$i];
1311 if (ref $sel eq 'SCALAR') {
1314 elsif( ref $sel eq 'REF' and ref $$sel eq 'ARRAY' ) {
1318 $self->throw_exception(
1319 'Result collapse not possible - selection from a has_many source redirected to the main object'
1320 ) if ($multiplied_selectors->{$sel} and $attrs->{as}[$i] !~ /\./);
1324 # hotspot - skip the setter
1325 my $res_class = $self->_result_class;
1327 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1328 $res_class->can ('inflate_result')
1329 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1332 my $infmap = $attrs->{as};
1334 $self->{_result_inflator}{is_core_row} = ( (
1337 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1338 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1340 $self->{_result_inflator}{is_hri} = ( (
1341 ! $self->{_result_inflator}{is_core_row}
1344 require DBIx::Class::ResultClass::HashRefInflator
1346 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1348 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1351 if (! $attrs->{_related_results_construction}) {
1352 # construct a much simpler array->hash folder for the one-table cases right here
1353 if ($self->{_result_inflator}{is_hri}) {
1354 for my $r (@$rows) {
1355 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1358 # FIXME SUBOPTIMAL this is a very very very hot spot
1359 # while rather optimal we can *still* do much better, by
1360 # building a smarter Row::inflate_result(), and
1361 # switch to feeding it data via a much leaner interface
1363 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1364 # this particular resultset size
1365 elsif (@$rows < 60) {
1366 for my $r (@$rows) {
1367 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1372 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1373 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1379 $self->{_result_inflator}{is_hri} ? 'hri'
1380 : $self->{_result_inflator}{is_core_row} ? 'classic_pruning'
1381 : 'classic_nonpruning'
1384 # $args and $attrs to _mk_row_parser are separated to delineate what is
1385 # core collapser stuff and what is dbic $rs specific
1386 @{$self->{_row_parser}{$parser_type}}{qw(cref nullcheck)} = $rsrc->_mk_row_parser({
1388 inflate_map => $infmap,
1389 collapse => $attrs->{collapse},
1390 premultiplied => $attrs->{_main_source_premultiplied},
1391 hri_style => $self->{_result_inflator}{is_hri},
1392 prune_null_branches => $self->{_result_inflator}{is_hri} || $self->{_result_inflator}{is_core_row},
1393 }, $attrs) unless $self->{_row_parser}{$parser_type}{cref};
1395 # column_info metadata historically hasn't been too reliable.
1396 # We need to start fixing this somehow (the collapse resolver
1397 # can't work without it). Add an explicit check for the *main*
1398 # result, hopefully this will gradually weed out such errors
1400 # FIXME - this is a temporary kludge that reduces performance
1401 # It is however necessary for the time being
1402 my ($unrolled_non_null_cols_to_check, $err);
1404 if (my $check_non_null_cols = $self->{_row_parser}{$parser_type}{nullcheck} ) {
1407 'Collapse aborted due to invalid ResultSource metadata - the following '
1408 . 'selections are declared non-nullable but NULLs were retrieved: '
1412 COL: for my $i (@$check_non_null_cols) {
1413 ! defined $_->[$i] and push @violating_idx, $i and next COL for @$rows;
1416 $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
1419 $unrolled_non_null_cols_to_check = join (',', @$check_non_null_cols);
1423 ($did_fetch_all or ! $attrs->{collapse}) ? undef
1424 : defined $unrolled_non_null_cols_to_check ? eval sprintf <<'EOS', $unrolled_non_null_cols_to_check
1426 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1427 my @r = $cursor->next or return;
1428 if (my @violating_idx = grep { ! defined $r[$_] } (%s) ) {
1429 $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
1435 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1436 my @r = $cursor->next or return;
1441 $self->{_row_parser}{$parser_type}{cref}->(
1443 $next_cref ? ( $next_cref, $self->{_stashed_rows} = [] ) : (),
1446 # Special-case multi-object HRI - there is no $inflator_cref pass
1447 unless ($self->{_result_inflator}{is_hri}) {
1448 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows
1452 # The @$rows check seems odd at first - why wouldn't we want to warn
1453 # regardless? The issue is things like find() etc, where the user
1454 # *knows* only one result will come back. In these cases the ->all
1455 # is not a pessimization, but rather something we actually want
1457 'Unable to properly collapse has_many results in iterator mode due '
1458 . 'to order criteria - performed an eager cursor slurp underneath. '
1459 . 'Consider using ->all() instead'
1460 ) if ( ! $fetch_all and @$rows > 1 );
1465 =head2 result_source
1469 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1471 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1475 An accessor for the primary ResultSource object from which this ResultSet
1482 =item Arguments: $result_class?
1484 =item Return Value: $result_class
1488 An accessor for the class to use when creating result objects. Defaults to
1489 C<< result_source->result_class >> - which in most cases is the name of the
1490 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1492 Note that changing the result_class will also remove any components
1493 that were originally loaded in the source class via
1494 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1495 in the original source class will not run.
1500 my ($self, $result_class) = @_;
1501 if ($result_class) {
1503 # don't fire this for an object
1504 $self->ensure_class_loaded($result_class)
1505 unless ref($result_class);
1507 if ($self->get_cache) {
1508 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1510 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1511 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1512 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1515 $self->_result_class($result_class);
1517 delete $self->{_result_inflator};
1519 $self->_result_class;
1526 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1528 =item Return Value: $count
1532 Performs an SQL C<COUNT> with the same query as the resultset was built
1533 with to find the number of elements. Passing arguments is equivalent to
1534 C<< $rs->search ($cond, \%attrs)->count >>
1540 return $self->search(@_)->count if @_ and defined $_[0];
1541 return scalar @{ $self->get_cache } if $self->get_cache;
1543 my $attrs = { %{ $self->_resolved_attrs } };
1545 # this is a little optimization - it is faster to do the limit
1546 # adjustments in software, instead of a subquery
1547 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1550 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1551 $crs = $self->_count_subq_rs ($attrs);
1554 $crs = $self->_count_rs ($attrs);
1556 my $count = $crs->next;
1558 $count -= $offset if $offset;
1559 $count = $rows if $rows and $rows < $count;
1560 $count = 0 if ($count < 0);
1569 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1571 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1575 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1576 This can be very handy for subqueries:
1578 ->search( { amount => $some_rs->count_rs->as_query } )
1580 As with regular resultsets the SQL query will be executed only after
1581 the resultset is accessed via L</next> or L</all>. That would return
1582 the same single value obtainable via L</count>.
1588 return $self->search(@_)->count_rs if @_;
1590 # this may look like a lack of abstraction (count() does about the same)
1591 # but in fact an _rs *must* use a subquery for the limits, as the
1592 # software based limiting can not be ported if this $rs is to be used
1593 # in a subquery itself (i.e. ->as_query)
1594 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1595 return $self->_count_subq_rs($self->{_attrs});
1598 return $self->_count_rs($self->{_attrs});
1603 # returns a ResultSetColumn object tied to the count query
1606 my ($self, $attrs) = @_;
1608 my $rsrc = $self->result_source;
1610 my $tmp_attrs = { %$attrs };
1611 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1612 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1614 # overwrite the selector (supplied by the storage)
1615 $rsrc->resultset_class->new($rsrc, {
1617 select => $rsrc->storage->_count_select ($rsrc, $attrs),
1619 })->get_column ('count');
1623 # same as above but uses a subquery
1625 sub _count_subq_rs {
1626 my ($self, $attrs) = @_;
1628 my $rsrc = $self->result_source;
1630 my $sub_attrs = { %$attrs };
1631 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1632 delete @{$sub_attrs}{qw/collapse columns as select order_by for/};
1634 # if we multi-prefetch we group_by something unique, as this is what we would
1635 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1636 if ( $attrs->{collapse} ) {
1637 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1638 $rsrc->_identifying_column_set || $self->throw_exception(
1639 'Unable to construct a unique group_by criteria properly collapsing the '
1640 . 'has_many prefetch before count()'
1645 # Calculate subquery selector
1646 if (my $g = $sub_attrs->{group_by}) {
1648 my $sql_maker = $rsrc->storage->sql_maker;
1650 # necessary as the group_by may refer to aliased functions
1652 for my $sel (@{$attrs->{select}}) {
1653 $sel_index->{$sel->{-as}} = $sel
1654 if (ref $sel eq 'HASH' and $sel->{-as});
1657 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1658 # also look for named aggregates referred in the having clause
1659 # having often contains scalarrefs - thus parse it out entirely
1661 if ($attrs->{having}) {
1662 local $sql_maker->{having_bind};
1663 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1664 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1665 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1666 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1667 # if we don't unset it we screw up retarded but unfortunately working
1668 # 'MAX(foo.bar)' => { '>', 3 }
1669 $sql_maker->{name_sep} = '';
1672 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1674 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1677 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1678 # and if all fails for an utterly naive quoted scalar-with-function
1679 while ($having_sql =~ /
1680 $rquote $sep $lquote (.+?) $rquote
1682 [\s,] \w+ \. (\w+) [\s,]
1684 [\s,] $lquote (.+?) $rquote [\s,]
1686 my $part = $1 || $2 || $3; # one of them matched if we got here
1687 unless ($seen_having{$part}++) {
1694 my $colpiece = $sel_index->{$_} || $_;
1696 # unqualify join-based group_by's. Arcane but possible query
1697 # also horrible horrible hack to alias a column (not a func.)
1698 # (probably need to introduce SQLA syntax)
1699 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1702 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1704 push @{$sub_attrs->{select}}, $colpiece;
1708 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1709 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1712 return $rsrc->resultset_class
1713 ->new ($rsrc, $sub_attrs)
1715 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1716 ->get_column ('count');
1720 =head2 count_literal
1722 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1723 should only be used in that context. See L</search_literal> for further info.
1727 =item Arguments: $sql_fragment, @standalone_bind_values
1729 =item Return Value: $count
1733 Counts the results in a literal query. Equivalent to calling L</search_literal>
1734 with the passed arguments, then L</count>.
1738 sub count_literal { shift->search_literal(@_)->count; }
1744 =item Arguments: none
1746 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1750 Returns all elements in the resultset.
1757 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1760 delete @{$self}{qw/_stashed_rows _stashed_results/};
1762 if (my $c = $self->get_cache) {
1766 $self->cursor->reset;
1768 my $objs = $self->_construct_results('fetch_all') || [];
1770 $self->set_cache($objs) if $self->{attrs}{cache};
1779 =item Arguments: none
1781 =item Return Value: $self
1785 Resets the resultset's cursor, so you can iterate through the elements again.
1786 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1794 delete @{$self}{qw/_stashed_rows _stashed_results/};
1795 $self->{all_cache_position} = 0;
1796 $self->cursor->reset;
1804 =item Arguments: none
1806 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1810 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1811 an object for the first result (or C<undef> if the resultset is empty).
1816 return $_[0]->reset->next;
1822 # Determines whether and what type of subquery is required for the $rs operation.
1823 # If grouping is necessary either supplies its own, or verifies the current one
1824 # After all is done delegates to the proper storage method.
1826 sub _rs_update_delete {
1827 my ($self, $op, $values) = @_;
1829 my $rsrc = $self->result_source;
1830 my $storage = $rsrc->schema->storage;
1832 my $attrs = { %{$self->_resolved_attrs} };
1834 my $join_classifications;
1835 my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
1837 # do we need a subquery for any reason?
1839 defined $existing_group_by
1841 # if {from} is unparseable wrap a subq
1842 ref($attrs->{from}) ne 'ARRAY'
1844 # limits call for a subq
1845 $self->_has_resolved_attr(qw/rows offset/)
1848 # simplify the joinmap, so we can further decide if a subq is necessary
1849 if (!$needs_subq and @{$attrs->{from}} > 1) {
1851 ($attrs->{from}, $join_classifications) =
1852 $storage->_prune_unused_joins ($attrs);
1854 # any non-pruneable non-local restricting joins imply subq
1855 $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
1858 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1860 (ref $attrs->{from}[0]) ne 'HASH'
1862 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1866 # do we need anything like a subquery?
1867 if (! $needs_subq) {
1868 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1869 # a condition containing 'me' or other table prefixes will not work
1870 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1872 my $sqla = $rsrc->storage->sql_maker;
1873 local $sqla->{_dequalify_idents} = 1;
1874 \[ $sqla->_recurse_where($self->{cond}) ];
1878 # we got this far - means it is time to wrap a subquery
1879 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1881 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1887 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1888 delete $attrs->{$_} for qw/select as collapse/;
1889 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1891 # this will be consumed by the pruner waaaaay down the stack
1892 $attrs->{_force_prune_multiplying_joins} = 1;
1894 my $subrs = (ref $self)->new($rsrc, $attrs);
1896 if (@$idcols == 1) {
1897 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1899 elsif ($storage->_use_multicolumn_in) {
1900 # no syntax for calling this properly yet
1901 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1902 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1903 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1908 # if all else fails - get all primary keys and operate over a ORed set
1909 # wrap in a transaction for consistency
1910 # this is where the group_by/multiplication starts to matter
1914 # we do not need to check pre-multipliers, since if the premulti is there, its
1915 # parent (who is multi) will be there too
1916 keys %{ $join_classifications->{multiplying} || {} }
1918 # make sure if there is a supplied group_by it matches the columns compiled above
1919 # perfectly. Anything else can not be sanely executed on most databases so croak
1920 # right then and there
1921 if ($existing_group_by) {
1922 my @current_group_by = map
1923 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1928 join ("\x00", sort @current_group_by)
1930 join ("\x00", sort @{$attrs->{columns}} )
1932 $self->throw_exception (
1933 "You have just attempted a $op operation on a resultset which does group_by"
1934 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1935 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1936 . ' kind of queries. Please retry the operation with a modified group_by or'
1937 . ' without using one at all.'
1942 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1945 $guard = $storage->txn_scope_guard;
1947 for my $row ($subrs->cursor->all) {
1949 { $idcols->[$_] => $row->[$_] }
1956 my $res = $cond ? $storage->$op (
1958 $op eq 'update' ? $values : (),
1962 $guard->commit if $guard;
1971 =item Arguments: \%values
1973 =item Return Value: $underlying_storage_rv
1977 Sets the specified columns in the resultset to the supplied values in a
1978 single query. Note that this will not run any accessor/set_column/update
1979 triggers, nor will it update any result object instances derived from this
1980 resultset (this includes the contents of the L<resultset cache|/set_cache>
1981 if any). See L</update_all> if you need to execute any on-update
1982 triggers or cascades defined either by you or a
1983 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1985 The return value is a pass through of what the underlying
1986 storage backend returned, and may vary. See L<DBI/execute> for the most
1991 Note that L</update> does not process/deflate any of the values passed in.
1992 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1993 ensure manually that any value passed to this method will stringify to
1994 something the RDBMS knows how to deal with. A notable example is the
1995 handling of L<DateTime> objects, for more info see:
1996 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
2001 my ($self, $values) = @_;
2002 $self->throw_exception('Values for update must be a hash')
2003 unless ref $values eq 'HASH';
2005 return $self->_rs_update_delete ('update', $values);
2012 =item Arguments: \%values
2014 =item Return Value: 1
2018 Fetches all objects and updates them one at a time via
2019 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2020 triggers, while L</update> will not.
2025 my ($self, $values) = @_;
2026 $self->throw_exception('Values for update_all must be a hash')
2027 unless ref $values eq 'HASH';
2029 my $guard = $self->result_source->schema->txn_scope_guard;
2030 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2039 =item Arguments: none
2041 =item Return Value: $underlying_storage_rv
2045 Deletes the rows matching this resultset in a single query. Note that this
2046 will not run any delete triggers, nor will it alter the
2047 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2048 derived from this resultset (this includes the contents of the
2049 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2050 execute any on-delete triggers or cascades defined either by you or a
2051 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2053 The return value is a pass through of what the underlying storage backend
2054 returned, and may vary. See L<DBI/execute> for the most common case.
2060 $self->throw_exception('delete does not accept any arguments')
2063 return $self->_rs_update_delete ('delete');
2070 =item Arguments: none
2072 =item Return Value: 1
2076 Fetches all objects and deletes them one at a time via
2077 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2078 triggers, while L</delete> will not.
2084 $self->throw_exception('delete_all does not accept any arguments')
2087 my $guard = $self->result_source->schema->txn_scope_guard;
2088 $_->delete for $self->all;
2097 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2099 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2103 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2110 The context of this method call has an important effect on what is
2111 submitted to storage. In void context data is fed directly to fastpath
2112 insertion routines provided by the underlying storage (most often
2113 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2114 L<insert|DBIx::Class::Row/insert> calls on the
2115 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2116 augmentation of these methods provided by components. For example if you
2117 are using something like L<DBIx::Class::UUIDColumns> to create primary
2118 keys for you, you will find that your PKs are empty. In this case you
2119 will have to explicitly force scalar or list context in order to create
2124 In non-void (scalar or list) context, this method is simply a wrapper
2125 for L</create>. Depending on list or scalar context either a list of
2126 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2127 containing these objects is returned.
2129 When supplying data in "arrayref of arrayrefs" invocation style, the
2130 first element should be a list of column names and each subsequent
2131 element should be a data value in the earlier specified column order.
2134 $schema->resultset("Artist")->populate([
2135 [ qw( artistid name ) ],
2136 [ 100, 'A Formally Unknown Singer' ],
2137 [ 101, 'A singer that jumped the shark two albums ago' ],
2138 [ 102, 'An actually cool singer' ],
2141 For the arrayref of hashrefs style each hashref should be a structure
2142 suitable for passing to L</create>. Multi-create is also permitted with
2145 $schema->resultset("Artist")->populate([
2146 { artistid => 4, name => 'Manufactured Crap', cds => [
2147 { title => 'My First CD', year => 2006 },
2148 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2151 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2152 { title => 'My parents sold me to a record company', year => 2005 },
2153 { title => 'Why Am I So Ugly?', year => 2006 },
2154 { title => 'I Got Surgery and am now Popular', year => 2007 }
2159 If you attempt a void-context multi-create as in the example above (each
2160 Artist also has the related list of CDs), and B<do not> supply the
2161 necessary autoinc foreign key information, this method will proxy to the
2162 less efficient L</create>, and then throw the Result objects away. In this
2163 case there are obviously no benefits to using this method over L</create>.
2170 # cruft placed in standalone method
2171 my $data = $self->_normalize_populate_args(@_);
2173 return unless @$data;
2175 if(defined wantarray) {
2176 my @created = map { $self->create($_) } @$data;
2177 return wantarray ? @created : \@created;
2180 my $first = $data->[0];
2182 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2183 # it relationship data
2184 my (@rels, @columns);
2185 my $rsrc = $self->result_source;
2186 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2187 for (keys %$first) {
2188 my $ref = ref $first->{$_};
2189 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2195 my @pks = $rsrc->primary_columns;
2197 ## do the belongs_to relationships
2198 foreach my $index (0..$#$data) {
2200 # delegate to create() for any dataset without primary keys with specified relationships
2201 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2203 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2204 my @ret = $self->populate($data);
2210 foreach my $rel (@rels) {
2211 next unless ref $data->[$index]->{$rel} eq "HASH";
2212 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2213 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2214 my $related = $result->result_source->_resolve_condition(
2215 $reverse_relinfo->{cond},
2221 delete $data->[$index]->{$rel};
2222 $data->[$index] = {%{$data->[$index]}, %$related};
2224 push @columns, keys %$related if $index == 0;
2228 ## inherit the data locked in the conditions of the resultset
2229 my ($rs_data) = $self->_merge_with_rscond({});
2230 delete @{$rs_data}{@columns};
2232 ## do bulk insert on current row
2233 $rsrc->storage->insert_bulk(
2235 [@columns, keys %$rs_data],
2236 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2239 ## do the has_many relationships
2240 foreach my $item (@$data) {
2244 foreach my $rel (@rels) {
2245 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2247 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2249 my $child = $main_row->$rel;
2251 my $related = $child->result_source->_resolve_condition(
2252 $rels->{$rel}{cond},
2258 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2259 my @populate = map { {%$_, %$related} } @rows_to_add;
2261 $child->populate( \@populate );
2268 # populate() arguments went over several incarnations
2269 # What we ultimately support is AoH
2270 sub _normalize_populate_args {
2271 my ($self, $arg) = @_;
2273 if (ref $arg eq 'ARRAY') {
2277 elsif (ref $arg->[0] eq 'HASH') {
2280 elsif (ref $arg->[0] eq 'ARRAY') {
2282 my @colnames = @{$arg->[0]};
2283 foreach my $values (@{$arg}[1 .. $#$arg]) {
2284 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2290 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2297 =item Arguments: none
2299 =item Return Value: L<$pager|Data::Page>
2303 Returns a L<Data::Page> object for the current resultset. Only makes
2304 sense for queries with a C<page> attribute.
2306 To get the full count of entries for a paged resultset, call
2307 C<total_entries> on the L<Data::Page> object.
2314 return $self->{pager} if $self->{pager};
2316 my $attrs = $self->{attrs};
2317 if (!defined $attrs->{page}) {
2318 $self->throw_exception("Can't create pager for non-paged rs");
2320 elsif ($attrs->{page} <= 0) {
2321 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2323 $attrs->{rows} ||= 10;
2325 # throw away the paging flags and re-run the count (possibly
2326 # with a subselect) to get the real total count
2327 my $count_attrs = { %$attrs };
2328 delete @{$count_attrs}{qw/rows offset page pager/};
2330 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2332 require DBIx::Class::ResultSet::Pager;
2333 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2334 sub { $total_rs->count }, #lazy-get the total
2336 $self->{attrs}{page},
2344 =item Arguments: $page_number
2346 =item Return Value: L<$resultset|/search>
2350 Returns a resultset for the $page_number page of the resultset on which page
2351 is called, where each page contains a number of rows equal to the 'rows'
2352 attribute set on the resultset (10 by default).
2357 my ($self, $page) = @_;
2358 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2365 =item Arguments: \%col_data
2367 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2371 Creates a new result object in the resultset's result class and returns
2372 it. The row is not inserted into the database at this point, call
2373 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2374 will tell you whether the result object has been inserted or not.
2376 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2381 my ($self, $values) = @_;
2383 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2386 $self->throw_exception( "new_result expects a hashref" )
2387 unless (ref $values eq 'HASH');
2389 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2391 my $new = $self->result_class->new({
2393 ( @$cols_from_relations
2394 ? (-cols_from_relations => $cols_from_relations)
2397 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2401 reftype($new) eq 'HASH'
2407 carp_unique (sprintf (
2408 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2409 $self->result_class,
2416 # _merge_with_rscond
2418 # Takes a simple hash of K/V data and returns its copy merged with the
2419 # condition already present on the resultset. Additionally returns an
2420 # arrayref of value/condition names, which were inferred from related
2421 # objects (this is needed for in-memory related objects)
2422 sub _merge_with_rscond {
2423 my ($self, $data) = @_;
2425 my (%new_data, @cols_from_relations);
2427 my $alias = $self->{attrs}{alias};
2429 if (! defined $self->{cond}) {
2430 # just massage $data below
2432 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2433 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2434 @cols_from_relations = keys %new_data;
2436 elsif (ref $self->{cond} ne 'HASH') {
2437 $self->throw_exception(
2438 "Can't abstract implicit construct, resultset condition not a hash"
2442 if ($self->{cond}) {
2443 my $implied = $self->_remove_alias(
2444 $self->result_source->schema->storage->_collapse_cond($self->{cond}),
2448 for my $c (keys %$implied) {
2449 my $v = $implied->{$c};
2450 if ( ! length ref $v or is_plain_value($v) ) {
2454 ref $v eq 'HASH' and keys %$v == 1 and exists $v->{'='} and is_literal_value($v->{'='})
2456 $new_data{$c} = $v->{'='};
2462 # precedence must be given to passed values over values inherited from
2463 # the cond, so the order here is important.
2466 %{ $self->_remove_alias($data, $alias) },
2469 return (\%new_data, \@cols_from_relations);
2472 # _has_resolved_attr
2474 # determines if the resultset defines at least one
2475 # of the attributes supplied
2477 # used to determine if a subquery is necessary
2479 # supports some virtual attributes:
2481 # This will scan for any joins being present on the resultset.
2482 # It is not a mere key-search but a deep inspection of {from}
2485 sub _has_resolved_attr {
2486 my ($self, @attr_names) = @_;
2488 my $attrs = $self->_resolved_attrs;
2492 for my $n (@attr_names) {
2493 if (grep { $n eq $_ } (qw/-join/) ) {
2494 $extra_checks{$n}++;
2498 my $attr = $attrs->{$n};
2500 next if not defined $attr;
2502 if (ref $attr eq 'HASH') {
2503 return 1 if keys %$attr;
2505 elsif (ref $attr eq 'ARRAY') {
2513 # a resolved join is expressed as a multi-level from
2515 $extra_checks{-join}
2517 ref $attrs->{from} eq 'ARRAY'
2519 @{$attrs->{from}} > 1
2527 # Remove the specified alias from the specified query hash. A copy is made so
2528 # the original query is not modified.
2531 my ($self, $query, $alias) = @_;
2533 my %orig = %{ $query || {} };
2536 foreach my $key (keys %orig) {
2538 $unaliased{$key} = $orig{$key};
2541 $unaliased{$1} = $orig{$key}
2542 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2552 =item Arguments: none
2554 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2558 Returns the SQL query and bind vars associated with the invocant.
2560 This is generally used as the RHS for a subquery.
2567 my $attrs = { %{ $self->_resolved_attrs } };
2569 my $aq = $self->result_source->storage->_select_args_to_query (
2570 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2580 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2582 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2586 my $artist = $schema->resultset('Artist')->find_or_new(
2587 { artist => 'fred' }, { key => 'artists' });
2589 $cd->cd_to_producer->find_or_new({ producer => $producer },
2590 { key => 'primary' });
2592 Find an existing record from this resultset using L</find>. if none exists,
2593 instantiate a new result object and return it. The object will not be saved
2594 into your storage until you call L<DBIx::Class::Row/insert> on it.
2596 You most likely want this method when looking for existing rows using a unique
2597 constraint that is not the primary key, or looking for related rows.
2599 If you want objects to be saved immediately, use L</find_or_create> instead.
2601 B<Note>: Make sure to read the documentation of L</find> and understand the
2602 significance of the C<key> attribute, as its lack may skew your search, and
2603 subsequently result in spurious new objects.
2605 B<Note>: Take care when using C<find_or_new> with a table having
2606 columns with default values that you intend to be automatically
2607 supplied by the database (e.g. an auto_increment primary key column).
2608 In normal usage, the value of such columns should NOT be included at
2609 all in the call to C<find_or_new>, even when set to C<undef>.
2615 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2616 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2617 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2620 return $self->new_result($hash);
2627 =item Arguments: \%col_data
2629 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2633 Attempt to create a single new row or a row with multiple related rows
2634 in the table represented by the resultset (and related tables). This
2635 will not check for duplicate rows before inserting, use
2636 L</find_or_create> to do that.
2638 To create one row for this resultset, pass a hashref of key/value
2639 pairs representing the columns of the table and the values you wish to
2640 store. If the appropriate relationships are set up, foreign key fields
2641 can also be passed an object representing the foreign row, and the
2642 value will be set to its primary key.
2644 To create related objects, pass a hashref of related-object column values
2645 B<keyed on the relationship name>. If the relationship is of type C<multi>
2646 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2647 The process will correctly identify columns holding foreign keys, and will
2648 transparently populate them from the keys of the corresponding relation.
2649 This can be applied recursively, and will work correctly for a structure
2650 with an arbitrary depth and width, as long as the relationships actually
2651 exists and the correct column data has been supplied.
2653 Instead of hashrefs of plain related data (key/value pairs), you may
2654 also pass new or inserted objects. New objects (not inserted yet, see
2655 L</new_result>), will be inserted into their appropriate tables.
2657 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2659 Example of creating a new row.
2661 $person_rs->create({
2662 name=>"Some Person",
2663 email=>"somebody@someplace.com"
2666 Example of creating a new row and also creating rows in a related C<has_many>
2667 or C<has_one> resultset. Note Arrayref.
2670 { artistid => 4, name => 'Manufactured Crap', cds => [
2671 { title => 'My First CD', year => 2006 },
2672 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2677 Example of creating a new row and also creating a row in a related
2678 C<belongs_to> resultset. Note Hashref.
2681 title=>"Music for Silly Walks",
2684 name=>"Silly Musician",
2692 When subclassing ResultSet never attempt to override this method. Since
2693 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2694 lot of the internals simply never call it, so your override will be
2695 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2696 or L<DBIx::Class::Row/insert> depending on how early in the
2697 L</create> process you need to intervene. See also warning pertaining to
2705 my ($self, $col_data) = @_;
2706 $self->throw_exception( "create needs a hashref" )
2707 unless ref $col_data eq 'HASH';
2708 return $self->new_result($col_data)->insert;
2711 =head2 find_or_create
2715 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2717 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2721 $cd->cd_to_producer->find_or_create({ producer => $producer },
2722 { key => 'primary' });
2724 Tries to find a record based on its primary key or unique constraints; if none
2725 is found, creates one and returns that instead.
2727 my $cd = $schema->resultset('CD')->find_or_create({
2729 artist => 'Massive Attack',
2730 title => 'Mezzanine',
2734 Also takes an optional C<key> attribute, to search by a specific key or unique
2735 constraint. For example:
2737 my $cd = $schema->resultset('CD')->find_or_create(
2739 artist => 'Massive Attack',
2740 title => 'Mezzanine',
2742 { key => 'cd_artist_title' }
2745 B<Note>: Make sure to read the documentation of L</find> and understand the
2746 significance of the C<key> attribute, as its lack may skew your search, and
2747 subsequently result in spurious row creation.
2749 B<Note>: Because find_or_create() reads from the database and then
2750 possibly inserts based on the result, this method is subject to a race
2751 condition. Another process could create a record in the table after
2752 the find has completed and before the create has started. To avoid
2753 this problem, use find_or_create() inside a transaction.
2755 B<Note>: Take care when using C<find_or_create> with a table having
2756 columns with default values that you intend to be automatically
2757 supplied by the database (e.g. an auto_increment primary key column).
2758 In normal usage, the value of such columns should NOT be included at
2759 all in the call to C<find_or_create>, even when set to C<undef>.
2761 See also L</find> and L</update_or_create>. For information on how to declare
2762 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2764 If you need to know if an existing row was found or a new one created use
2765 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2766 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2769 my $cd = $schema->resultset('CD')->find_or_new({
2771 artist => 'Massive Attack',
2772 title => 'Mezzanine',
2776 if( !$cd->in_storage ) {
2783 sub find_or_create {
2785 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2786 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2787 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2790 return $self->create($hash);
2793 =head2 update_or_create
2797 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2799 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2803 $resultset->update_or_create({ col => $val, ... });
2805 Like L</find_or_create>, but if a row is found it is immediately updated via
2806 C<< $found_row->update (\%col_data) >>.
2809 Takes an optional C<key> attribute to search on a specific unique constraint.
2812 # In your application
2813 my $cd = $schema->resultset('CD')->update_or_create(
2815 artist => 'Massive Attack',
2816 title => 'Mezzanine',
2819 { key => 'cd_artist_title' }
2822 $cd->cd_to_producer->update_or_create({
2823 producer => $producer,
2829 B<Note>: Make sure to read the documentation of L</find> and understand the
2830 significance of the C<key> attribute, as its lack may skew your search, and
2831 subsequently result in spurious row creation.
2833 B<Note>: Take care when using C<update_or_create> with a table having
2834 columns with default values that you intend to be automatically
2835 supplied by the database (e.g. an auto_increment primary key column).
2836 In normal usage, the value of such columns should NOT be included at
2837 all in the call to C<update_or_create>, even when set to C<undef>.
2839 See also L</find> and L</find_or_create>. For information on how to declare
2840 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2842 If you need to know if an existing row was updated or a new one created use
2843 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2844 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2849 sub update_or_create {
2851 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2852 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2854 my $row = $self->find($cond, $attrs);
2856 $row->update($cond);
2860 return $self->create($cond);
2863 =head2 update_or_new
2867 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2869 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2873 $resultset->update_or_new({ col => $val, ... });
2875 Like L</find_or_new> but if a row is found it is immediately updated via
2876 C<< $found_row->update (\%col_data) >>.
2880 # In your application
2881 my $cd = $schema->resultset('CD')->update_or_new(
2883 artist => 'Massive Attack',
2884 title => 'Mezzanine',
2887 { key => 'cd_artist_title' }
2890 if ($cd->in_storage) {
2891 # the cd was updated
2894 # the cd is not yet in the database, let's insert it
2898 B<Note>: Make sure to read the documentation of L</find> and understand the
2899 significance of the C<key> attribute, as its lack may skew your search, and
2900 subsequently result in spurious new objects.
2902 B<Note>: Take care when using C<update_or_new> with a table having
2903 columns with default values that you intend to be automatically
2904 supplied by the database (e.g. an auto_increment primary key column).
2905 In normal usage, the value of such columns should NOT be included at
2906 all in the call to C<update_or_new>, even when set to C<undef>.
2908 See also L</find>, L</find_or_create> and L</find_or_new>.
2914 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2915 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2917 my $row = $self->find( $cond, $attrs );
2918 if ( defined $row ) {
2919 $row->update($cond);
2923 return $self->new_result($cond);
2930 =item Arguments: none
2932 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2936 Gets the contents of the cache for the resultset, if the cache is set.
2938 The cache is populated either by using the L</prefetch> attribute to
2939 L</search> or by calling L</set_cache>.
2951 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2953 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2957 Sets the contents of the cache for the resultset. Expects an arrayref
2958 of objects of the same class as those produced by the resultset. Note that
2959 if the cache is set, the resultset will return the cached objects rather
2960 than re-querying the database even if the cache attr is not set.
2962 The contents of the cache can also be populated by using the
2963 L</prefetch> attribute to L</search>.
2968 my ( $self, $data ) = @_;
2969 $self->throw_exception("set_cache requires an arrayref")
2970 if defined($data) && (ref $data ne 'ARRAY');
2971 $self->{all_cache} = $data;
2978 =item Arguments: none
2980 =item Return Value: undef
2984 Clears the cache for the resultset.
2989 shift->set_cache(undef);
2996 =item Arguments: none
2998 =item Return Value: true, if the resultset has been paginated
3006 return !!$self->{attrs}{page};
3013 =item Arguments: none
3015 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3023 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3026 =head2 related_resultset
3030 =item Arguments: $rel_name
3032 =item Return Value: L<$resultset|/search>
3036 Returns a related resultset for the supplied relationship name.
3038 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3042 sub related_resultset {
3043 my ($self, $rel) = @_;
3045 return $self->{related_resultsets}{$rel}
3046 if defined $self->{related_resultsets}{$rel};
3048 return $self->{related_resultsets}{$rel} = do {
3049 my $rsrc = $self->result_source;
3050 my $rel_info = $rsrc->relationship_info($rel);
3052 $self->throw_exception(
3053 "search_related: result source '" . $rsrc->source_name .
3054 "' has no such relationship $rel")
3057 my $attrs = $self->_chain_relationship($rel);
3059 my $join_count = $attrs->{seen_join}{$rel};
3061 my $alias = $self->result_source->storage
3062 ->relname_to_table_alias($rel, $join_count);
3064 # since this is search_related, and we already slid the select window inwards
3065 # (the select/as attrs were deleted in the beginning), we need to flip all
3066 # left joins to inner, so we get the expected results
3067 # read the comment on top of the actual function to see what this does
3068 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3071 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3072 delete @{$attrs}{qw(result_class alias)};
3074 my $rel_source = $rsrc->related_source($rel);
3078 # The reason we do this now instead of passing the alias to the
3079 # search_rs below is that if you wrap/overload resultset on the
3080 # source you need to know what alias it's -going- to have for things
3081 # to work sanely (e.g. RestrictWithObject wants to be able to add
3082 # extra query restrictions, and these may need to be $alias.)
3084 my $rel_attrs = $rel_source->resultset_attributes;
3085 local $rel_attrs->{alias} = $alias;
3087 $rel_source->resultset
3091 where => $attrs->{where},
3095 if (my $cache = $self->get_cache) {
3096 my @related_cache = map
3097 { @{$_->related_resultset($rel)->get_cache||[]} }
3101 $new->set_cache(\@related_cache) if @related_cache;
3108 =head2 current_source_alias
3112 =item Arguments: none
3114 =item Return Value: $source_alias
3118 Returns the current table alias for the result source this resultset is built
3119 on, that will be used in the SQL query. Usually it is C<me>.
3121 Currently the source alias that refers to the result set returned by a
3122 L</search>/L</find> family method depends on how you got to the resultset: it's
3123 C<me> by default, but eg. L</search_related> aliases it to the related result
3124 source name (and keeps C<me> referring to the original result set). The long
3125 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3126 (and make this method unnecessary).
3128 Thus it's currently necessary to use this method in predefined queries (see
3129 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3130 source alias of the current result set:
3132 # in a result set class
3134 my ($self, $user) = @_;
3136 my $me = $self->current_source_alias;
3138 return $self->search({
3139 "$me.modified" => $user->id,
3145 sub current_source_alias {
3146 return (shift->{attrs} || {})->{alias} || 'me';
3149 =head2 as_subselect_rs
3153 =item Arguments: none
3155 =item Return Value: L<$resultset|/search>
3159 Act as a barrier to SQL symbols. The resultset provided will be made into a
3160 "virtual view" by including it as a subquery within the from clause. From this
3161 point on, any joined tables are inaccessible to ->search on the resultset (as if
3162 it were simply where-filtered without joins). For example:
3164 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3166 # 'x' now pollutes the query namespace
3168 # So the following works as expected
3169 my $ok_rs = $rs->search({'x.other' => 1});
3171 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3172 # def) we look for one row with contradictory terms and join in another table
3173 # (aliased 'x_2') which we never use
3174 my $broken_rs = $rs->search({'x.name' => 'def'});
3176 my $rs2 = $rs->as_subselect_rs;
3178 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3179 my $not_joined_rs = $rs2->search({'x.other' => 1});
3181 # works as expected: finds a 'table' row related to two x rows (abc and def)
3182 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3184 Another example of when one might use this would be to select a subset of
3185 columns in a group by clause:
3187 my $rs = $schema->resultset('Bar')->search(undef, {
3188 group_by => [qw{ id foo_id baz_id }],
3189 })->as_subselect_rs->search(undef, {
3190 columns => [qw{ id foo_id }]
3193 In the above example normally columns would have to be equal to the group by,
3194 but because we isolated the group by into a subselect the above works.
3198 sub as_subselect_rs {
3201 my $attrs = $self->_resolved_attrs;
3203 my $fresh_rs = (ref $self)->new (
3204 $self->result_source
3207 # these pieces will be locked in the subquery
3208 delete $fresh_rs->{cond};
3209 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3211 return $fresh_rs->search( {}, {
3213 $attrs->{alias} => $self->as_query,
3214 -alias => $attrs->{alias},
3215 -rsrc => $self->result_source,
3217 alias => $attrs->{alias},
3221 # This code is called by search_related, and makes sure there
3222 # is clear separation between the joins before, during, and
3223 # after the relationship. This information is needed later
3224 # in order to properly resolve prefetch aliases (any alias
3225 # with a relation_chain_depth less than the depth of the
3226 # current prefetch is not considered)
3228 # The increments happen twice per join. An even number means a
3229 # relationship specified via a search_related, whereas an odd
3230 # number indicates a join/prefetch added via attributes
3232 # Also this code will wrap the current resultset (the one we
3233 # chain to) in a subselect IFF it contains limiting attributes
3234 sub _chain_relationship {
3235 my ($self, $rel) = @_;
3236 my $source = $self->result_source;
3237 my $attrs = { %{$self->{attrs}||{}} };
3239 # we need to take the prefetch the attrs into account before we
3240 # ->_resolve_join as otherwise they get lost - captainL
3241 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3243 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3245 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3248 my @force_subq_attrs = qw/offset rows group_by having/;
3251 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3253 $self->_has_resolved_attr (@force_subq_attrs)
3255 # Nuke the prefetch (if any) before the new $rs attrs
3256 # are resolved (prefetch is useless - we are wrapping
3257 # a subquery anyway).
3258 my $rs_copy = $self->search;
3259 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3260 $rs_copy->{attrs}{join},
3261 delete $rs_copy->{attrs}{prefetch},
3266 -alias => $attrs->{alias},
3267 $attrs->{alias} => $rs_copy->as_query,
3269 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3270 $seen->{-relation_chain_depth} = 0;
3272 elsif ($attrs->{from}) { #shallow copy suffices
3273 $from = [ @{$attrs->{from}} ];
3278 -alias => $attrs->{alias},
3279 $attrs->{alias} => $source->from,
3283 my $jpath = ($seen->{-relation_chain_depth})
3284 ? $from->[-1][0]{-join_path}
3287 my @requested_joins = $source->_resolve_join(
3294 push @$from, @requested_joins;
3296 $seen->{-relation_chain_depth}++;
3298 # if $self already had a join/prefetch specified on it, the requested
3299 # $rel might very well be already included. What we do in this case
3300 # is effectively a no-op (except that we bump up the chain_depth on
3301 # the join in question so we could tell it *is* the search_related)
3304 # we consider the last one thus reverse
3305 for my $j (reverse @requested_joins) {
3306 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3307 if ($rel eq $last_j) {
3308 $j->[0]{-relation_chain_depth}++;
3314 unless ($already_joined) {
3315 push @$from, $source->_resolve_join(
3323 $seen->{-relation_chain_depth}++;
3325 return {%$attrs, from => $from, seen_join => $seen};
3328 sub _resolved_attrs {
3330 return $self->{_attrs} if $self->{_attrs};
3332 my $attrs = { %{ $self->{attrs} || {} } };
3333 my $source = $self->result_source;
3334 my $alias = $attrs->{alias};
3336 $self->throw_exception("Specifying distinct => 1 in conjunction with collapse => 1 is unsupported")
3337 if $attrs->{collapse} and $attrs->{distinct};
3339 # default selection list
3340 $attrs->{columns} = [ $source->columns ]
3341 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3343 # merge selectors together
3344 for (qw/columns select as/) {
3345 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3346 if $attrs->{$_} or $attrs->{"+$_"};
3349 # disassemble columns
3351 if (my $cols = delete $attrs->{columns}) {
3352 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3353 if (ref $c eq 'HASH') {
3354 for my $as (sort keys %$c) {
3355 push @sel, $c->{$as};
3366 # when trying to weed off duplicates later do not go past this point -
3367 # everything added from here on is unbalanced "anyone's guess" stuff
3368 my $dedup_stop_idx = $#as;
3370 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3372 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3373 if $attrs->{select};
3375 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3376 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3378 # disqualify all $alias.col as-bits (inflate-map mandated)
3379 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3381 # de-duplicate the result (remove *identical* select/as pairs)
3382 # and also die on duplicate {as} pointing to different {select}s
3383 # not using a c-style for as the condition is prone to shrinkage
3386 while ($i <= $dedup_stop_idx) {
3387 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3392 elsif ($seen->{$as[$i]}++) {
3393 $self->throw_exception(
3394 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3402 $attrs->{select} = \@sel;
3403 $attrs->{as} = \@as;
3405 $attrs->{from} ||= [{
3407 -alias => $self->{attrs}{alias},
3408 $self->{attrs}{alias} => $source->from,
3411 if ( $attrs->{join} || $attrs->{prefetch} ) {
3413 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3414 if ref $attrs->{from} ne 'ARRAY';
3416 my $join = (delete $attrs->{join}) || {};
3418 if ( defined $attrs->{prefetch} ) {
3419 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3422 $attrs->{from} = # have to copy here to avoid corrupting the original
3424 @{ $attrs->{from} },
3425 $source->_resolve_join(
3428 { %{ $attrs->{seen_join} || {} } },
3429 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3430 ? $attrs->{from}[-1][0]{-join_path}
3437 if ( defined $attrs->{order_by} ) {
3438 $attrs->{order_by} = (
3439 ref( $attrs->{order_by} ) eq 'ARRAY'
3440 ? [ @{ $attrs->{order_by} } ]
3441 : [ $attrs->{order_by} || () ]
3445 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3446 $attrs->{group_by} = [ $attrs->{group_by} ];
3450 # generate selections based on the prefetch helper
3451 my ($prefetch, @prefetch_select, @prefetch_as);
3452 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3453 if defined $attrs->{prefetch};
3457 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3458 if $attrs->{_dark_selector};
3460 $self->throw_exception("Specifying prefetch in conjunction with an explicit collapse => 0 is unsupported")
3461 if defined $attrs->{collapse} and ! $attrs->{collapse};
3463 $attrs->{collapse} = 1;
3465 # this is a separate structure (we don't look in {from} directly)
3466 # as the resolver needs to shift things off the lists to work
3467 # properly (identical-prefetches on different branches)
3469 if (ref $attrs->{from} eq 'ARRAY') {
3471 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3473 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3474 next unless $j->[0]{-alias};
3475 next unless $j->[0]{-join_path};
3476 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3478 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3481 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3482 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3486 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3488 # save these for after distinct resolution
3489 @prefetch_select = map { $_->[0] } @prefetch;
3490 @prefetch_as = map { $_->[1] } @prefetch;
3493 # run through the resulting joinstructure (starting from our current slot)
3494 # and unset collapse if proven unnecessary
3496 # also while we are at it find out if the current root source has
3497 # been premultiplied by previous related_source chaining
3499 # this allows to predict whether a root object with all other relation
3500 # data set to NULL is in fact unique
3501 if ($attrs->{collapse}) {
3503 if (ref $attrs->{from} eq 'ARRAY') {
3505 if (@{$attrs->{from}} == 1) {
3506 # no joins - no collapse
3507 $attrs->{collapse} = 0;
3510 # find where our table-spec starts
3511 my @fromlist = @{$attrs->{from}};
3513 my $t = shift @fromlist;
3516 # me vs join from-spec distinction - a ref means non-root
3517 if (ref $t eq 'ARRAY') {
3519 $is_multi ||= ! $t->{-is_single};
3521 last if ($t->{-alias} && $t->{-alias} eq $alias);
3522 $attrs->{_main_source_premultiplied} ||= $is_multi;
3525 # no non-singles remaining, nor any premultiplication - nothing to collapse
3527 ! $attrs->{_main_source_premultiplied}
3529 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3531 $attrs->{collapse} = 0;
3537 # if we can not analyze the from - err on the side of safety
3538 $attrs->{_main_source_premultiplied} = 1;
3542 # generate the distinct induced group_by before injecting the prefetched select/as parts
3543 if (delete $attrs->{distinct}) {
3544 if ($attrs->{group_by}) {
3545 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3548 $attrs->{_grouped_by_distinct} = 1;
3549 # distinct affects only the main selection part, not what prefetch may add below
3550 ($attrs->{group_by}, my $new_order) = $source->storage->_group_over_selection($attrs);
3552 # FIXME possibly ignore a rewritten order_by (may turn out to be an issue)
3553 # The thinking is: if we are collapsing the subquerying prefetch engine will
3554 # rip stuff apart for us anyway, and we do not want to have a potentially
3555 # function-converted external order_by
3556 # ( there is an explicit if ( collapse && _grouped_by_distinct ) check in DBIHacks )
3557 $attrs->{order_by} = $new_order unless $attrs->{collapse};
3561 # inject prefetch-bound selection (if any)
3562 push @{$attrs->{select}}, @prefetch_select;
3563 push @{$attrs->{as}}, @prefetch_as;
3565 # whether we can get away with the dumbest (possibly DBI-internal) collapser
3566 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3567 $attrs->{_related_results_construction} = 1;
3570 # if both page and offset are specified, produce a combined offset
3571 # even though it doesn't make much sense, this is what pre 081xx has
3573 if (my $page = delete $attrs->{page}) {
3575 ($attrs->{rows} * ($page - 1))
3577 ($attrs->{offset} || 0)
3581 return $self->{_attrs} = $attrs;
3585 my ($self, $attr) = @_;
3587 if (ref $attr eq 'HASH') {
3588 return $self->_rollout_hash($attr);
3589 } elsif (ref $attr eq 'ARRAY') {
3590 return $self->_rollout_array($attr);
3596 sub _rollout_array {
3597 my ($self, $attr) = @_;
3600 foreach my $element (@{$attr}) {
3601 if (ref $element eq 'HASH') {
3602 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3603 } elsif (ref $element eq 'ARRAY') {
3604 # XXX - should probably recurse here
3605 push( @rolled_array, @{$self->_rollout_array($element)} );
3607 push( @rolled_array, $element );
3610 return \@rolled_array;
3614 my ($self, $attr) = @_;
3617 foreach my $key (keys %{$attr}) {
3618 push( @rolled_array, { $key => $attr->{$key} } );
3620 return \@rolled_array;
3623 sub _calculate_score {
3624 my ($self, $a, $b) = @_;
3626 if (defined $a xor defined $b) {
3629 elsif (not defined $a) {
3633 if (ref $b eq 'HASH') {
3634 my ($b_key) = keys %{$b};
3635 if (ref $a eq 'HASH') {
3636 my ($a_key) = keys %{$a};
3637 if ($a_key eq $b_key) {
3638 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3643 return ($a eq $b_key) ? 1 : 0;
3646 if (ref $a eq 'HASH') {
3647 my ($a_key) = keys %{$a};
3648 return ($b eq $a_key) ? 1 : 0;
3650 return ($b eq $a) ? 1 : 0;
3655 sub _merge_joinpref_attr {
3656 my ($self, $orig, $import) = @_;
3658 return $import unless defined($orig);
3659 return $orig unless defined($import);
3661 $orig = $self->_rollout_attr($orig);
3662 $import = $self->_rollout_attr($import);
3665 foreach my $import_element ( @{$import} ) {
3666 # find best candidate from $orig to merge $b_element into
3667 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3668 foreach my $orig_element ( @{$orig} ) {
3669 my $score = $self->_calculate_score( $orig_element, $import_element );
3670 if ($score > $best_candidate->{score}) {
3671 $best_candidate->{position} = $position;
3672 $best_candidate->{score} = $score;
3676 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3677 $import_key = '' if not defined $import_key;
3679 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3680 push( @{$orig}, $import_element );
3682 my $orig_best = $orig->[$best_candidate->{position}];
3683 # merge orig_best and b_element together and replace original with merged
3684 if (ref $orig_best ne 'HASH') {
3685 $orig->[$best_candidate->{position}] = $import_element;
3686 } elsif (ref $import_element eq 'HASH') {
3687 my ($key) = keys %{$orig_best};
3688 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3691 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3694 return @$orig ? $orig : ();
3702 require Hash::Merge;
3703 my $hm = Hash::Merge->new;
3705 $hm->specify_behavior({
3708 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3710 if ($defl xor $defr) {
3711 return [ $defl ? $_[0] : $_[1] ];
3716 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3720 return [$_[0], $_[1]];
3724 return $_[1] if !defined $_[0];
3725 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3726 return [$_[0], @{$_[1]}]
3729 return [] if !defined $_[0] and !keys %{$_[1]};
3730 return [ $_[1] ] if !defined $_[0];
3731 return [ $_[0] ] if !keys %{$_[1]};
3732 return [$_[0], $_[1]]
3737 return $_[0] if !defined $_[1];
3738 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3739 return [@{$_[0]}, $_[1]]
3742 my @ret = @{$_[0]} or return $_[1];
3743 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3744 my %idx = map { $_ => 1 } @ret;
3745 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3749 return [ $_[1] ] if ! @{$_[0]};
3750 return $_[0] if !keys %{$_[1]};
3751 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3752 return [ @{$_[0]}, $_[1] ];
3757 return [] if !keys %{$_[0]} and !defined $_[1];
3758 return [ $_[0] ] if !defined $_[1];
3759 return [ $_[1] ] if !keys %{$_[0]};
3760 return [$_[0], $_[1]]
3763 return [] if !keys %{$_[0]} and !@{$_[1]};
3764 return [ $_[0] ] if !@{$_[1]};
3765 return $_[1] if !keys %{$_[0]};
3766 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3767 return [ $_[0], @{$_[1]} ];
3770 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3771 return [ $_[0] ] if !keys %{$_[1]};
3772 return [ $_[1] ] if !keys %{$_[0]};
3773 return [ $_[0] ] if $_[0] eq $_[1];
3774 return [ $_[0], $_[1] ];
3777 } => 'DBIC_RS_ATTR_MERGER');
3781 return $hm->merge ($_[1], $_[2]);
3785 sub STORABLE_freeze {
3786 my ($self, $cloning) = @_;
3787 my $to_serialize = { %$self };
3789 # A cursor in progress can't be serialized (and would make little sense anyway)
3790 # the parser can be regenerated (and can't be serialized)
3791 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3793 # nor is it sensical to store a not-yet-fired-count pager
3794 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3795 delete $to_serialize->{pager};
3798 Storable::nfreeze($to_serialize);
3801 # need this hook for symmetry
3803 my ($self, $cloning, $serialized) = @_;
3805 %$self = %{ Storable::thaw($serialized) };
3811 =head2 throw_exception
3813 See L<DBIx::Class::Schema/throw_exception> for details.
3817 sub throw_exception {
3820 if (ref $self and my $rsrc = $self->result_source) {
3821 $rsrc->throw_exception(@_)
3824 DBIx::Class::Exception->throw(@_);
3832 # XXX: FIXME: Attributes docs need clearing up
3836 Attributes are used to refine a ResultSet in various ways when
3837 searching for data. They can be passed to any method which takes an
3838 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3841 Default attributes can be set on the result class using
3842 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3843 the CAVEATS on that feature before using it!)
3845 These are in no particular order:
3851 =item Value: ( $order_by | \@order_by | \%order_by )
3855 Which column(s) to order the results by.
3857 [The full list of suitable values is documented in
3858 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3861 If a single column name, or an arrayref of names is supplied, the
3862 argument is passed through directly to SQL. The hashref syntax allows
3863 for connection-agnostic specification of ordering direction:
3865 For descending order:
3867 order_by => { -desc => [qw/col1 col2 col3/] }
3869 For explicit ascending order:
3871 order_by => { -asc => 'col' }
3873 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3874 supported, although you are strongly encouraged to use the hashref
3875 syntax as outlined above.
3881 =item Value: \@columns | \%columns | $column
3885 Shortcut to request a particular set of columns to be retrieved. Each
3886 column spec may be a string (a table column name), or a hash (in which
3887 case the key is the C<as> value, and the value is used as the C<select>
3888 expression). Adds C<me.> onto the start of any column without a C<.> in
3889 it and sets C<select> from that, then auto-populates C<as> from
3890 C<select> as normal. (You may also use the C<cols> attribute, as in
3891 earlier versions of DBIC, but this is deprecated.)
3893 Essentially C<columns> does the same as L</select> and L</as>.
3895 columns => [ 'foo', { bar => 'baz' } ]
3899 select => [qw/foo baz/],
3906 =item Value: \@columns
3910 Indicates additional columns to be selected from storage. Works the same as
3911 L</columns> but adds columns to the selection. (You may also use the
3912 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3913 deprecated). For example:-
3915 $schema->resultset('CD')->search(undef, {
3916 '+columns' => ['artist.name'],
3920 would return all CDs and include a 'name' column to the information
3921 passed to object inflation. Note that the 'artist' is the name of the
3922 column (or relationship) accessor, and 'name' is the name of the column
3923 accessor in the related table.
3925 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3926 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3927 unary plus operator before it.
3929 =head2 include_columns
3933 =item Value: \@columns
3937 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3943 =item Value: \@select_columns
3947 Indicates which columns should be selected from the storage. You can use
3948 column names, or in the case of RDBMS back ends, function or stored procedure
3951 $rs = $schema->resultset('Employee')->search(undef, {
3954 { count => 'employeeid' },
3955 { max => { length => 'name' }, -as => 'longest_name' }
3960 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3962 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3963 use L</select>, to instruct DBIx::Class how to store the result of the column.
3964 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3965 identifier aliasing. You can however alias a function, so you can use it in
3966 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3967 attribute> supplied as shown in the example above.
3969 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3970 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3971 unary plus operator before it.
3977 Indicates additional columns to be selected from storage. Works the same as
3978 L</select> but adds columns to the default selection, instead of specifying
3987 =item Value: \@inflation_names
3991 Indicates column names for object inflation. That is L</as> indicates the
3992 slot name in which the column value will be stored within the
3993 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
3994 identifier by the C<get_column> method (or via the object accessor B<if one
3995 with the same name already exists>) as shown below. The L</as> attribute has
3996 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
3998 $rs = $schema->resultset('Employee')->search(undef, {
4001 { count => 'employeeid' },
4002 { max => { length => 'name' }, -as => 'longest_name' }
4011 If the object against which the search is performed already has an accessor
4012 matching a column name specified in C<as>, the value can be retrieved using
4013 the accessor as normal:
4015 my $name = $employee->name();
4017 If on the other hand an accessor does not exist in the object, you need to
4018 use C<get_column> instead:
4020 my $employee_count = $employee->get_column('employee_count');
4022 You can create your own accessors if required - see
4023 L<DBIx::Class::Manual::Cookbook> for details.
4029 Indicates additional column names for those added via L</+select>. See L</as>.
4037 =item Value: ($rel_name | \@rel_names | \%rel_names)
4041 Contains a list of relationships that should be joined for this query. For
4044 # Get CDs by Nine Inch Nails
4045 my $rs = $schema->resultset('CD')->search(
4046 { 'artist.name' => 'Nine Inch Nails' },
4047 { join => 'artist' }
4050 Can also contain a hash reference to refer to the other relation's relations.
4053 package MyApp::Schema::Track;
4054 use base qw/DBIx::Class/;
4055 __PACKAGE__->table('track');
4056 __PACKAGE__->add_columns(qw/trackid cd position title/);
4057 __PACKAGE__->set_primary_key('trackid');
4058 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4061 # In your application
4062 my $rs = $schema->resultset('Artist')->search(
4063 { 'track.title' => 'Teardrop' },
4065 join => { cd => 'track' },
4066 order_by => 'artist.name',
4070 You need to use the relationship (not the table) name in conditions,
4071 because they are aliased as such. The current table is aliased as "me", so
4072 you need to use me.column_name in order to avoid ambiguity. For example:
4074 # Get CDs from 1984 with a 'Foo' track
4075 my $rs = $schema->resultset('CD')->search(
4078 'tracks.name' => 'Foo'
4080 { join => 'tracks' }
4083 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4084 similarly for a third time). For e.g.
4086 my $rs = $schema->resultset('Artist')->search({
4087 'cds.title' => 'Down to Earth',
4088 'cds_2.title' => 'Popular',
4090 join => [ qw/cds cds/ ],
4093 will return a set of all artists that have both a cd with title 'Down
4094 to Earth' and a cd with title 'Popular'.
4096 If you want to fetch related objects from other tables as well, see L</prefetch>
4099 NOTE: An internal join-chain pruner will discard certain joins while
4100 constructing the actual SQL query, as long as the joins in question do not
4101 affect the retrieved result. This for example includes 1:1 left joins
4102 that are not part of the restriction specification (WHERE/HAVING) nor are
4103 a part of the query selection.
4105 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4111 =item Value: (0 | 1)
4115 When set to a true value, indicates that any rows fetched from joined has_many
4116 relationships are to be aggregated into the corresponding "parent" object. For
4117 example, the resultset:
4119 my $rs = $schema->resultset('CD')->search({}, {
4120 '+columns' => [ qw/ tracks.title tracks.position / ],
4125 While executing the following query:
4127 SELECT me.*, tracks.title, tracks.position
4129 LEFT JOIN track tracks
4130 ON tracks.cdid = me.cdid
4132 Will return only as many objects as there are rows in the CD source, even
4133 though the result of the query may span many rows. Each of these CD objects
4134 will in turn have multiple "Track" objects hidden behind the has_many
4135 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4136 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4137 product"), with each CD object containing exactly one of all fetched Track data.
4139 When a collapse is requested on a non-ordered resultset, an order by some
4140 unique part of the main source (the left-most table) is inserted automatically.
4141 This is done so that the resultset is allowed to be "lazy" - calling
4142 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4143 object with all of its related data.
4145 If an L</order_by> is already declared, and orders the resultset in a way that
4146 makes collapsing as described above impossible (e.g. C<< ORDER BY
4147 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4148 switch to "eager" mode and slurp the entire resultset before constructing the
4149 first object returned by L</next>.
4151 Setting this attribute on a resultset that does not join any has_many
4152 relations is a no-op.
4154 For a more in-depth discussion, see L</PREFETCHING>.
4160 =item Value: ($rel_name | \@rel_names | \%rel_names)
4164 This attribute is a shorthand for specifying a L</join> spec, adding all
4165 columns from the joined related sources as L</+columns> and setting
4166 L</collapse> to a true value. For example, the following two queries are
4169 my $rs = $schema->resultset('Artist')->search({}, {
4170 prefetch => { cds => ['genre', 'tracks' ] },
4175 my $rs = $schema->resultset('Artist')->search({}, {
4176 join => { cds => ['genre', 'tracks' ] },
4180 { +{ "cds.$_" => "cds.$_" } }
4181 $schema->source('Artist')->related_source('cds')->columns
4184 { +{ "cds.genre.$_" => "genre.$_" } }
4185 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4188 { +{ "cds.tracks.$_" => "tracks.$_" } }
4189 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4194 Both producing the following SQL:
4196 SELECT me.artistid, me.name, me.rank, me.charfield,
4197 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4198 genre.genreid, genre.name,
4199 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4202 ON cds.artist = me.artistid
4203 LEFT JOIN genre genre
4204 ON genre.genreid = cds.genreid
4205 LEFT JOIN track tracks
4206 ON tracks.cd = cds.cdid
4207 ORDER BY me.artistid
4209 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4210 the arguments are properly merged and generally do the right thing. For
4211 example, you may want to do the following:
4213 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4214 { 'genre.genreid' => undef },
4216 join => { cds => 'genre' },
4221 Which generates the following SQL:
4223 SELECT me.artistid, me.name, me.rank, me.charfield,
4224 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4227 ON cds.artist = me.artistid
4228 LEFT JOIN genre genre
4229 ON genre.genreid = cds.genreid
4230 WHERE genre.genreid IS NULL
4231 ORDER BY me.artistid
4233 For a more in-depth discussion, see L</PREFETCHING>.
4239 =item Value: $source_alias
4243 Sets the source alias for the query. Normally, this defaults to C<me>, but
4244 nested search queries (sub-SELECTs) might need specific aliases set to
4245 reference inner queries. For example:
4248 ->related_resultset('CDs')
4249 ->related_resultset('Tracks')
4251 'track.id' => { -ident => 'none_search.id' },
4255 my $ids = $self->search({
4258 alias => 'none_search',
4259 group_by => 'none_search.id',
4260 })->get_column('id')->as_query;
4262 $self->search({ id => { -in => $ids } })
4264 This attribute is directly tied to L</current_source_alias>.
4274 Makes the resultset paged and specifies the page to retrieve. Effectively
4275 identical to creating a non-pages resultset and then calling ->page($page)
4278 If L</rows> attribute is not specified it defaults to 10 rows per page.
4280 When you have a paged resultset, L</count> will only return the number
4281 of rows in the page. To get the total, use the L</pager> and call
4282 C<total_entries> on it.
4292 Specifies the maximum number of rows for direct retrieval or the number of
4293 rows per page if the page attribute or method is used.
4299 =item Value: $offset
4303 Specifies the (zero-based) row number for the first row to be returned, or the
4304 of the first row of the first page if paging is used.
4306 =head2 software_limit
4310 =item Value: (0 | 1)
4314 When combined with L</rows> and/or L</offset> the generated SQL will not
4315 include any limit dialect stanzas. Instead the entire result will be selected
4316 as if no limits were specified, and DBIC will perform the limit locally, by
4317 artificially advancing and finishing the resulting L</cursor>.
4319 This is the recommended way of performing resultset limiting when no sane RDBMS
4320 implementation is available (e.g.
4321 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4322 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4328 =item Value: \@columns
4332 A arrayref of columns to group by. Can include columns of joined tables.
4334 group_by => [qw/ column1 column2 ... /]
4340 =item Value: $condition
4344 HAVING is a select statement attribute that is applied between GROUP BY and
4345 ORDER BY. It is applied to the after the grouping calculations have been
4348 having => { 'count_employee' => { '>=', 100 } }
4350 or with an in-place function in which case literal SQL is required:
4352 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4358 =item Value: (0 | 1)
4362 Set to 1 to automatically generate a L</group_by> clause based on the selection
4363 (including intelligent handling of L</order_by> contents). Note that the group
4364 criteria calculation takes place over the B<final> selection. This includes
4365 any L</+columns>, L</+select> or L</order_by> additions in subsequent
4366 L</search> calls, and standalone columns selected via
4367 L<DBIx::Class::ResultSetColumn> (L</get_column>). A notable exception are the
4368 extra selections specified via L</prefetch> - such selections are explicitly
4369 excluded from group criteria calculations.
4371 If the final ResultSet also explicitly defines a L</group_by> attribute, this
4372 setting is ignored and an appropriate warning is issued.
4378 Adds to the WHERE clause.
4380 # only return rows WHERE deleted IS NULL for all searches
4381 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4383 Can be overridden by passing C<< { where => undef } >> as an attribute
4386 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4392 Set to 1 to cache search results. This prevents extra SQL queries if you
4393 revisit rows in your ResultSet:
4395 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4397 while( my $artist = $resultset->next ) {
4401 $rs->first; # without cache, this would issue a query
4403 By default, searches are not cached.
4405 For more examples of using these attributes, see
4406 L<DBIx::Class::Manual::Cookbook>.
4412 =item Value: ( 'update' | 'shared' | \$scalar )
4416 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4417 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4422 DBIx::Class supports arbitrary related data prefetching from multiple related
4423 sources. Any combination of relationship types and column sets are supported.
4424 If L<collapsing|/collapse> is requested, there is an additional requirement of
4425 selecting enough data to make every individual object uniquely identifiable.
4427 Here are some more involved examples, based on the following relationship map:
4430 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4431 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4432 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4434 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4436 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4440 my $rs = $schema->resultset('Tag')->search(
4449 The initial search results in SQL like the following:
4451 SELECT tag.*, cd.*, artist.* FROM tag
4452 JOIN cd ON tag.cd = cd.cdid
4453 JOIN artist ON cd.artist = artist.artistid
4455 L<DBIx::Class> has no need to go back to the database when we access the
4456 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4459 Simple prefetches will be joined automatically, so there is no need
4460 for a C<join> attribute in the above search.
4462 The L</prefetch> attribute can be used with any of the relationship types
4463 and multiple prefetches can be specified together. Below is a more complex
4464 example that prefetches a CD's artist, its liner notes (if present),
4465 the cover image, the tracks on that CD, and the guests on those
4468 my $rs = $schema->resultset('CD')->search(
4472 { artist => 'record_label'}, # belongs_to => belongs_to
4473 'liner_note', # might_have
4474 'cover_image', # has_one
4475 { tracks => 'guests' }, # has_many => has_many
4480 This will produce SQL like the following:
4482 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4486 ON artist.artistid = me.artistid
4487 JOIN record_label record_label
4488 ON record_label.labelid = artist.labelid
4489 LEFT JOIN track tracks
4490 ON tracks.cdid = me.cdid
4491 LEFT JOIN guest guests
4492 ON guests.trackid = track.trackid
4493 LEFT JOIN liner_notes liner_note
4494 ON liner_note.cdid = me.cdid
4495 JOIN cd_artwork cover_image
4496 ON cover_image.cdid = me.cdid
4499 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4500 C<tracks>, and C<guests> of the CD will all be available through the
4501 relationship accessors without the need for additional queries to the
4506 Prefetch does a lot of deep magic. As such, it may not behave exactly
4507 as you might expect.
4513 Prefetch uses the L</cache> to populate the prefetched relationships. This
4514 may or may not be what you want.
4518 If you specify a condition on a prefetched relationship, ONLY those
4519 rows that match the prefetched condition will be fetched into that relationship.
4520 This means that adding prefetch to a search() B<may alter> what is returned by
4521 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4523 my $artist_rs = $schema->resultset('Artist')->search({
4529 my $count = $artist_rs->first->cds->count;
4531 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4533 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4535 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4537 That cmp_ok() may or may not pass depending on the datasets involved. In other
4538 words the C<WHERE> condition would apply to the entire dataset, just like
4539 it would in regular SQL. If you want to add a condition only to the "right side"
4540 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4541 condition|DBIx::Class::Relationship::Base/condition>
4545 =head1 DBIC BIND VALUES
4547 Because DBIC may need more information to bind values than just the column name
4548 and value itself, it uses a special format for both passing and receiving bind
4549 values. Each bind value should be composed of an arrayref of
4550 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4556 If present (in any form), this is what is being passed directly to bind_param.
4557 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4558 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4560 If this is specified, all other bind options described below are ignored.
4564 If present, this is used to infer the actual bind attribute by passing to
4565 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4566 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4568 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4569 currently drivers are expected to "Do the Right Thing" when given a common
4570 datatype name. (Not ideal, but that's what we got at this point.)
4574 Currently used to correctly allocate buffers for bind_param_inout().
4575 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4576 or to a sensible value based on the "data_type".
4580 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4581 explicitly specified they are never overridden). Also used by some weird DBDs,
4582 where the column name should be available at bind_param time (e.g. Oracle).
4586 For backwards compatibility and convenience, the following shortcuts are
4589 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4590 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4591 [ undef, $val ] === [ {}, $val ]
4592 $val === [ {}, $val ]
4594 =head1 AUTHOR AND CONTRIBUTORS
4596 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4600 You may distribute this code under the same terms as Perl itself.