1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::ResultSetColumn;
8 use Scalar::Util qw/blessed weaken reftype/;
10 use Data::Compare (); # no imports!!! guard against insane architecture
12 # not importing first() as it will clash with our own method
16 # De-duplication in _merge_attr() is disabled, but left in for reference
17 # (the merger is used for other things that ought not to be de-duped)
18 *__HM_DEDUP = sub () { 0 };
28 # this is real - CDBICompat overrides it with insanity
29 # yes, prototype won't matter, but that's for now ;)
32 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
36 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
40 my $users_rs = $schema->resultset('User');
41 while( $user = $users_rs->next) {
42 print $user->username;
45 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
46 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
50 A ResultSet is an object which stores a set of conditions representing
51 a query. It is the backbone of DBIx::Class (i.e. the really
52 important/useful bit).
54 No SQL is executed on the database when a ResultSet is created, it
55 just stores all the conditions needed to create the query.
57 A basic ResultSet representing the data of an entire table is returned
58 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
59 L<Source|DBIx::Class::Manual::Glossary/Source> name.
61 my $users_rs = $schema->resultset('User');
63 A new ResultSet is returned from calling L</search> on an existing
64 ResultSet. The new one will contain all the conditions of the
65 original, plus any new conditions added in the C<search> call.
67 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
68 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
71 The query that the ResultSet represents is B<only> executed against
72 the database when these methods are called:
73 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
75 If a resultset is used in a numeric context it returns the L</count>.
76 However, if it is used in a boolean context it is B<always> true. So if
77 you want to check if a resultset has any results, you must use C<if $rs
80 =head1 CUSTOM ResultSet CLASSES THAT USE Moose
82 If you want to make your custom ResultSet classes with L<Moose>, use a template
85 package MyApp::Schema::ResultSet::User;
88 use namespace::autoclean;
90 extends 'DBIx::Class::ResultSet';
92 sub BUILDARGS { $_[2] }
96 __PACKAGE__->meta->make_immutable;
100 The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
101 clash with the regular ResultSet constructor. Alternatively, you can use:
103 __PACKAGE__->meta->make_immutable(inline_constructor => 0);
105 The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
106 signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
110 =head2 Chaining resultsets
112 Let's say you've got a query that needs to be run to return some data
113 to the user. But, you have an authorization system in place that
114 prevents certain users from seeing certain information. So, you want
115 to construct the basic query in one method, but add constraints to it in
120 my $request = $self->get_request; # Get a request object somehow.
121 my $schema = $self->result_source->schema;
123 my $cd_rs = $schema->resultset('CD')->search({
124 title => $request->param('title'),
125 year => $request->param('year'),
128 $cd_rs = $self->apply_security_policy( $cd_rs );
130 return $cd_rs->all();
133 sub apply_security_policy {
142 =head3 Resolving conditions and attributes
144 When a resultset is chained from another resultset (ie:
145 C<my $new_rs = $old_rs->search(\%extra_cond, \%attrs)>), conditions
146 and attributes with the same keys need resolving.
148 If any of L</columns>, L</select>, L</as> are present, they reset the
149 original selection, and start the selection "clean".
151 The L</join>, L</prefetch>, L</+columns>, L</+select>, L</+as> attributes
152 are merged into the existing ones from the original resultset.
154 The L</where> and L</having> attributes, and any search conditions, are
155 merged with an SQL C<AND> to the existing condition from the original
158 All other attributes are overridden by any new ones supplied in the
161 =head2 Multiple queries
163 Since a resultset just defines a query, you can do all sorts of
164 things with it with the same object.
166 # Don't hit the DB yet.
167 my $cd_rs = $schema->resultset('CD')->search({
168 title => 'something',
172 # Each of these hits the DB individually.
173 my $count = $cd_rs->count;
174 my $most_recent = $cd_rs->get_column('date_released')->max();
175 my @records = $cd_rs->all;
177 And it's not just limited to SELECT statements.
183 $cd_rs->create({ artist => 'Fred' });
185 Which is the same as:
187 $schema->resultset('CD')->create({
188 title => 'something',
193 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
201 =item Arguments: L<$source|DBIx::Class::ResultSource>, L<\%attrs?|/ATTRIBUTES>
203 =item Return Value: L<$resultset|/search>
207 The resultset constructor. Takes a source object (usually a
208 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
209 L</ATTRIBUTES> below). Does not perform any queries -- these are
210 executed as needed by the other methods.
212 Generally you never construct a resultset manually. Instead you get one
214 C<< $schema->L<resultset|DBIx::Class::Schema/resultset>('$source_name') >>
215 or C<< $another_resultset->L<search|/search>(...) >> (the later called in
218 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
224 If called on an object, proxies to L</new_result> instead, so
226 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
228 will return a CD object, not a ResultSet, and is equivalent to:
230 my $cd = $schema->resultset('CD')->new_result({ title => 'Spoon' });
232 Please also keep in mind that many internals call L</new_result> directly,
233 so overloading this method with the idea of intercepting new result object
234 creation B<will not work>. See also warning pertaining to L</create>.
242 return $class->new_result(@_) if ref $class;
244 my ($source, $attrs) = @_;
245 $source = $source->resolve
246 if $source->isa('DBIx::Class::ResultSourceHandle');
247 $attrs = { %{$attrs||{}} };
249 if ($attrs->{page}) {
250 $attrs->{rows} ||= 10;
253 $attrs->{alias} ||= 'me';
256 result_source => $source,
257 cond => $attrs->{where},
262 # if there is a dark selector, this means we are already in a
263 # chain and the cleanup/sanification was taken care of by
265 $self->_normalize_selection($attrs)
266 unless $attrs->{_dark_selector};
269 $attrs->{result_class} || $source->result_class
279 =item Arguments: L<$cond|DBIx::Class::SQLMaker> | undef, L<\%attrs?|/ATTRIBUTES>
281 =item Return Value: $resultset (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
285 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
286 my $new_rs = $cd_rs->search({ year => 2005 });
288 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
289 # year = 2005 OR year = 2004
291 In list context, C<< ->all() >> is called implicitly on the resultset, thus
292 returning a list of L<result|DBIx::Class::Manual::ResultClass> objects instead.
293 To avoid that, use L</search_rs>.
295 If you need to pass in additional attributes but no additional condition,
296 call it as C<search(undef, \%attrs)>.
298 # "SELECT name, artistid FROM $artist_table"
299 my @all_artists = $schema->resultset('Artist')->search(undef, {
300 columns => [qw/name artistid/],
303 For a list of attributes that can be passed to C<search>, see
304 L</ATTRIBUTES>. For more examples of using this function, see
305 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
306 documentation for the first argument, see L<SQL::Abstract>
307 and its extension L<DBIx::Class::SQLMaker>.
309 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
313 Note that L</search> does not process/deflate any of the values passed in the
314 L<SQL::Abstract>-compatible search condition structure. This is unlike other
315 condition-bound methods L</new_result>, L</create> and L</find>. The user must ensure
316 manually that any value passed to this method will stringify to something the
317 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
318 objects, for more info see:
319 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
325 my $rs = $self->search_rs( @_ );
330 elsif (defined wantarray) {
334 # we can be called by a relationship helper, which in
335 # turn may be called in void context due to some braindead
336 # overload or whatever else the user decided to be clever
337 # at this particular day. Thus limit the exception to
338 # external code calls only
339 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
340 if (caller)[0] !~ /^\QDBIx::Class::/;
350 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
352 =item Return Value: L<$resultset|/search>
356 This method does the same exact thing as search() except it will
357 always return a resultset, even in list context.
364 my $rsrc = $self->result_source;
365 my ($call_cond, $call_attrs);
367 # Special-case handling for (undef, undef) or (undef)
368 # Note that (foo => undef) is valid deprecated syntax
369 @_ = () if not scalar grep { defined $_ } @_;
375 # fish out attrs in the ($condref, $attr) case
376 elsif (@_ == 2 and ( ! defined $_[0] or (ref $_[0]) ne '') ) {
377 ($call_cond, $call_attrs) = @_;
380 $self->throw_exception('Odd number of arguments to search')
384 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead'
385 unless $rsrc->result_class->isa('DBIx::Class::CDBICompat');
387 for my $i (0 .. $#_) {
389 $self->throw_exception ('All keys in condition key/value pairs must be plain scalars')
390 if (! defined $_[$i] or ref $_[$i] ne '');
396 # see if we can keep the cache (no $rs changes)
398 my %safe = (alias => 1, cache => 1);
399 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
402 ref $call_cond eq 'HASH' && ! keys %$call_cond
404 ref $call_cond eq 'ARRAY' && ! @$call_cond
406 $cache = $self->get_cache;
409 my $old_attrs = { %{$self->{attrs}} };
410 my $old_having = delete $old_attrs->{having};
411 my $old_where = delete $old_attrs->{where};
413 my $new_attrs = { %$old_attrs };
415 # take care of call attrs (only if anything is changing)
416 if ($call_attrs and keys %$call_attrs) {
418 # copy for _normalize_selection
419 $call_attrs = { %$call_attrs };
421 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns/;
423 # reset the current selector list if new selectors are supplied
424 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
425 delete @{$old_attrs}{(@selector_attrs, '_dark_selector')};
428 # Normalize the new selector list (operates on the passed-in attr structure)
429 # Need to do it on every chain instead of only once on _resolved_attrs, in
430 # order to allow detection of empty vs partial 'as'
431 $call_attrs->{_dark_selector} = $old_attrs->{_dark_selector}
432 if $old_attrs->{_dark_selector};
433 $self->_normalize_selection ($call_attrs);
435 # start with blind overwriting merge, exclude selector attrs
436 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
437 delete @{$new_attrs}{@selector_attrs};
439 for (@selector_attrs) {
440 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
441 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
444 # older deprecated name, use only if {columns} is not there
445 if (my $c = delete $new_attrs->{cols}) {
446 carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
447 if ($new_attrs->{columns}) {
448 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
451 $new_attrs->{columns} = $c;
456 # join/prefetch use their own crazy merging heuristics
457 foreach my $key (qw/join prefetch/) {
458 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
459 if exists $call_attrs->{$key};
462 # stack binds together
463 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
467 for ($old_where, $call_cond) {
469 $new_attrs->{where} = $self->_stack_cond (
470 $_, $new_attrs->{where}
475 if (defined $old_having) {
476 $new_attrs->{having} = $self->_stack_cond (
477 $old_having, $new_attrs->{having}
481 my $rs = (ref $self)->new($rsrc, $new_attrs);
483 $rs->set_cache($cache) if ($cache);
489 sub _normalize_selection {
490 my ($self, $attrs) = @_;
493 if ( exists $attrs->{include_columns} ) {
494 carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
495 $attrs->{'+columns'} = $self->_merge_attr(
496 $attrs->{'+columns'}, delete $attrs->{include_columns}
500 # columns are always placed first, however
502 # Keep the X vs +X separation until _resolved_attrs time - this allows to
503 # delay the decision on whether to use a default select list ($rsrc->columns)
504 # allowing stuff like the remove_columns helper to work
506 # select/as +select/+as pairs need special handling - the amount of select/as
507 # elements in each pair does *not* have to be equal (think multicolumn
508 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
509 # supplied at all) - try to infer the alias, either from the -as parameter
510 # of the selector spec, or use the parameter whole if it looks like a column
511 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
512 # is ok as well), but make sure no more additions to the 'as' chain take place
513 for my $pref ('', '+') {
515 my ($sel, $as) = map {
516 my $key = "${pref}${_}";
518 my $val = [ ref $attrs->{$key} eq 'ARRAY'
520 : $attrs->{$key} || ()
522 delete $attrs->{$key};
526 if (! @$as and ! @$sel ) {
529 elsif (@$as and ! @$sel) {
530 $self->throw_exception(
531 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
535 # no as part supplied at all - try to deduce (unless explicit end of named selection is declared)
536 # if any @$as has been supplied we assume the user knows what (s)he is doing
537 # and blindly keep stacking up pieces
538 unless ($attrs->{_dark_selector}) {
541 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
542 push @$as, $_->{-as};
544 # assume any plain no-space, no-parenthesis string to be a column spec
545 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
546 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
549 # if all else fails - raise a flag that no more aliasing will be allowed
551 $attrs->{_dark_selector} = {
553 string => ($dark_sel_dumper ||= do {
554 require Data::Dumper::Concise;
555 Data::Dumper::Concise::DumperObject()->Indent(0);
556 })->Values([$_])->Dump
564 elsif (@$as < @$sel) {
565 $self->throw_exception(
566 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
569 elsif ($pref and $attrs->{_dark_selector}) {
570 $self->throw_exception(
571 "Unable to process named '+select', resultset contains an unnamed selector $attrs->{_dark_selector}{string}"
577 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
578 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
583 my ($self, $left, $right) = @_;
585 # collapse single element top-level conditions
586 # (single pass only, unlikely to need recursion)
587 for ($left, $right) {
588 if (ref $_ eq 'ARRAY') {
596 elsif (ref $_ eq 'HASH') {
597 my ($first, $more) = keys %$_;
600 if (! defined $first) {
604 elsif (! defined $more) {
605 if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
608 elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
615 # merge hashes with weeding out of duplicates (simple cases only)
616 if (ref $left eq 'HASH' and ref $right eq 'HASH') {
618 # shallow copy to destroy
619 $right = { %$right };
620 for (grep { exists $right->{$_} } keys %$left) {
621 # the use of eq_deeply here is justified - the rhs of an
622 # expression can contain a lot of twisted weird stuff
623 delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
626 $right = undef unless keys %$right;
630 if (defined $left xor defined $right) {
631 return defined $left ? $left : $right;
633 elsif (! defined $left) {
637 return { -and => [ $left, $right ] };
641 =head2 search_literal
643 B<CAVEAT>: C<search_literal> is provided for Class::DBI compatibility and
644 should only be used in that context. C<search_literal> is a convenience
645 method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
646 want to ensure columns are bound correctly, use L</search>.
648 See L<DBIx::Class::Manual::Cookbook/Searching> and
649 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
650 require C<search_literal>.
654 =item Arguments: $sql_fragment, @standalone_bind_values
656 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
660 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
661 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
663 Pass a literal chunk of SQL to be added to the conditional part of the
666 Example of how to use C<search> instead of C<search_literal>
668 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
669 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
674 my ($self, $sql, @bind) = @_;
676 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
679 return $self->search(\[ $sql, map [ {} => $_ ], @bind ], ($attr || () ));
686 =item Arguments: \%columns_values | @pk_values, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
688 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
692 Finds and returns a single row based on supplied criteria. Takes either a
693 hashref with the same format as L</create> (including inference of foreign
694 keys from related objects), or a list of primary key values in the same
695 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
696 declaration on the L</result_source>.
698 In either case an attempt is made to combine conditions already existing on
699 the resultset with the condition passed to this method.
701 To aid with preparing the correct query for the storage you may supply the
702 C<key> attribute, which is the name of a
703 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
704 unique constraint corresponding to the
705 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
706 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
707 to construct a query that satisfies the named unique constraint fully (
708 non-NULL values for each column member of the constraint) an exception is
711 If no C<key> is specified, the search is carried over all unique constraints
712 which are fully defined by the available condition.
714 If no such constraint is found, C<find> currently defaults to a simple
715 C<< search->(\%column_values) >> which may or may not do what you expect.
716 Note that this fallback behavior may be deprecated in further versions. If
717 you need to search with arbitrary conditions - use L</search>. If the query
718 resulting from this fallback produces more than one row, a warning to the
719 effect is issued, though only the first row is constructed and returned as
722 In addition to C<key>, L</find> recognizes and applies standard
723 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
725 Note that if you have extra concerns about the correctness of the resulting
726 query you need to specify the C<key> attribute and supply the entire condition
727 as an argument to find (since it is not always possible to perform the
728 combination of the resultset condition with the supplied one, especially if
729 the resultset condition contains literal sql).
731 For example, to find a row by its primary key:
733 my $cd = $schema->resultset('CD')->find(5);
735 You can also find a row by a specific unique constraint:
737 my $cd = $schema->resultset('CD')->find(
739 artist => 'Massive Attack',
740 title => 'Mezzanine',
742 { key => 'cd_artist_title' }
745 See also L</find_or_create> and L</update_or_create>.
751 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
753 my $rsrc = $self->result_source;
756 if (exists $attrs->{key}) {
757 $constraint_name = defined $attrs->{key}
759 : $self->throw_exception("An undefined 'key' resultset attribute makes no sense")
763 # Parse out the condition from input
766 if (ref $_[0] eq 'HASH') {
767 $call_cond = { %{$_[0]} };
770 # if only values are supplied we need to default to 'primary'
771 $constraint_name = 'primary' unless defined $constraint_name;
773 my @c_cols = $rsrc->unique_constraint_columns($constraint_name);
775 $self->throw_exception(
776 "No constraint columns, maybe a malformed '$constraint_name' constraint?"
779 $self->throw_exception (
780 'find() expects either a column/value hashref, or a list of values '
781 . "corresponding to the columns of the specified unique constraint '$constraint_name'"
782 ) unless @c_cols == @_;
785 @{$call_cond}{@c_cols} = @_;
789 for my $key (keys %$call_cond) {
791 my $keyref = ref($call_cond->{$key})
793 my $relinfo = $rsrc->relationship_info($key)
795 my $val = delete $call_cond->{$key};
797 next if $keyref eq 'ARRAY'; # has_many for multi_create
799 my $rel_q = $rsrc->_resolve_condition(
800 $relinfo->{cond}, $val, $key, $key
802 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
803 @related{keys %$rel_q} = values %$rel_q;
807 # relationship conditions take precedence (?)
808 @{$call_cond}{keys %related} = values %related;
810 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
812 if (defined $constraint_name) {
813 $final_cond = $self->_qualify_cond_columns (
815 $self->_build_unique_cond (
823 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
824 # This means that we got here after a merger of relationship conditions
825 # in ::Relationship::Base::search_related (the row method), and furthermore
826 # the relationship is of the 'single' type. This means that the condition
827 # provided by the relationship (already attached to $self) is sufficient,
828 # as there can be only one row in the database that would satisfy the
832 # no key was specified - fall down to heuristics mode:
833 # run through all unique queries registered on the resultset, and
834 # 'OR' all qualifying queries together
835 my (@unique_queries, %seen_column_combinations);
836 for my $c_name ($rsrc->unique_constraint_names) {
837 next if $seen_column_combinations{
838 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
841 push @unique_queries, try {
842 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
846 $final_cond = @unique_queries
847 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
848 : $self->_non_unique_find_fallback ($call_cond, $attrs)
852 # Run the query, passing the result_class since it should propagate for find
853 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
854 if ($rs->_resolved_attrs->{collapse}) {
856 carp "Query returned more than one row" if $rs->next;
864 # This is a stop-gap method as agreed during the discussion on find() cleanup:
865 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
867 # It is invoked when find() is called in legacy-mode with insufficiently-unique
868 # condition. It is provided for overrides until a saner way forward is devised
870 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
871 # the road. Please adjust your tests accordingly to catch this situation early
872 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
874 # The method will not be removed without an adequately complete replacement
875 # for strict-mode enforcement
876 sub _non_unique_find_fallback {
877 my ($self, $cond, $attrs) = @_;
879 return $self->_qualify_cond_columns(
881 exists $attrs->{alias}
883 : $self->{attrs}{alias}
888 sub _qualify_cond_columns {
889 my ($self, $cond, $alias) = @_;
891 my %aliased = %$cond;
892 for (keys %aliased) {
893 $aliased{"$alias.$_"} = delete $aliased{$_}
900 sub _build_unique_cond {
901 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
903 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
905 # combination may fail if $self->{cond} is non-trivial
906 my ($final_cond) = try {
907 $self->_merge_with_rscond ($extra_cond)
912 # trim out everything not in $columns
913 $final_cond = { map {
914 exists $final_cond->{$_}
915 ? ( $_ => $final_cond->{$_} )
919 if (my @missing = grep
920 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
923 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
925 join (', ', map { "'$_'" } @missing),
932 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
934 my @undefs = sort grep { ! defined $final_cond->{$_} } (keys %$final_cond)
936 carp_unique ( sprintf (
937 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
938 . 'values in column(s): %s). This is almost certainly not what you wanted, '
939 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
941 join (', ', map { "'$_'" } @undefs),
948 =head2 search_related
952 =item Arguments: $rel_name, $cond?, L<\%attrs?|/ATTRIBUTES>
954 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
958 $new_rs = $cd_rs->search_related('artist', {
962 Searches the specified relationship, optionally specifying a condition and
963 attributes for matching records. See L</ATTRIBUTES> for more information.
965 In list context, C<< ->all() >> is called implicitly on the resultset, thus
966 returning a list of result objects instead. To avoid that, use L</search_related_rs>.
968 See also L</search_related_rs>.
973 return shift->related_resultset(shift)->search(@_);
976 =head2 search_related_rs
978 This method works exactly the same as search_related, except that
979 it guarantees a resultset, even in list context.
983 sub search_related_rs {
984 return shift->related_resultset(shift)->search_rs(@_);
991 =item Arguments: none
993 =item Return Value: L<$cursor|DBIx::Class::Cursor>
997 Returns a storage-driven cursor to the given resultset. See
998 L<DBIx::Class::Cursor> for more information.
1005 return $self->{cursor} ||= do {
1006 my $attrs = { %{$self->_resolved_attrs } };
1007 $self->result_source->storage->select(
1008 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
1017 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1019 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1023 my $cd = $schema->resultset('CD')->single({ year => 2001 });
1025 Inflates the first result without creating a cursor if the resultset has
1026 any records in it; if not returns C<undef>. Used by L</find> as a lean version
1029 While this method can take an optional search condition (just like L</search>)
1030 being a fast-code-path it does not recognize search attributes. If you need to
1031 add extra joins or similar, call L</search> and then chain-call L</single> on the
1032 L<DBIx::Class::ResultSet> returned.
1038 As of 0.08100, this method enforces the assumption that the preceding
1039 query returns only one row. If more than one row is returned, you will receive
1042 Query returned more than one row
1044 In this case, you should be using L</next> or L</find> instead, or if you really
1045 know what you are doing, use the L</rows> attribute to explicitly limit the size
1048 This method will also throw an exception if it is called on a resultset prefetching
1049 has_many, as such a prefetch implies fetching multiple rows from the database in
1050 order to assemble the resulting object.
1057 my ($self, $where) = @_;
1059 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
1062 my $attrs = { %{$self->_resolved_attrs} };
1064 $self->throw_exception(
1065 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
1066 ) if $attrs->{collapse};
1069 if (defined $attrs->{where}) {
1072 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
1073 $where, delete $attrs->{where} ]
1076 $attrs->{where} = $where;
1080 my $data = [ $self->result_source->storage->select_single(
1081 $attrs->{from}, $attrs->{select},
1082 $attrs->{where}, $attrs
1084 return undef unless @$data;
1085 $self->{_stashed_rows} = [ $data ];
1086 $self->_construct_results->[0];
1092 # Recursively collapse the query, accumulating values for each column.
1094 sub _collapse_query {
1095 my ($self, $query, $collapsed) = @_;
1099 if (ref $query eq 'ARRAY') {
1100 foreach my $subquery (@$query) {
1101 next unless ref $subquery; # -or
1102 $collapsed = $self->_collapse_query($subquery, $collapsed);
1105 elsif (ref $query eq 'HASH') {
1106 if (keys %$query and (keys %$query)[0] eq '-and') {
1107 foreach my $subquery (@{$query->{-and}}) {
1108 $collapsed = $self->_collapse_query($subquery, $collapsed);
1112 foreach my $col (keys %$query) {
1113 my $value = $query->{$col};
1114 $collapsed->{$col}{$value}++;
1126 =item Arguments: L<$cond?|DBIx::Class::SQLMaker>
1128 =item Return Value: L<$resultsetcolumn|DBIx::Class::ResultSetColumn>
1132 my $max_length = $rs->get_column('length')->max;
1134 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1139 my ($self, $column) = @_;
1140 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1148 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1150 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1154 # WHERE title LIKE '%blue%'
1155 $cd_rs = $rs->search_like({ title => '%blue%'});
1157 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1158 that this is simply a convenience method retained for ex Class::DBI users.
1159 You most likely want to use L</search> with specific operators.
1161 For more information, see L<DBIx::Class::Manual::Cookbook>.
1163 This method is deprecated and will be removed in 0.09. Use L</search()>
1164 instead. An example conversion is:
1166 ->search_like({ foo => 'bar' });
1170 ->search({ foo => { like => 'bar' } });
1177 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1178 .' Instead use ->search({ x => { -like => "y%" } })'
1179 .' (note the outer pair of {}s - they are important!)'
1181 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1182 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1183 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1184 return $class->search($query, { %$attrs });
1191 =item Arguments: $first, $last
1193 =item Return Value: L<$resultset|/search> (scalar context) | L<@result_objs|DBIx::Class::Manual::ResultClass> (list context)
1197 Returns a resultset or object list representing a subset of elements from the
1198 resultset slice is called on. Indexes are from 0, i.e., to get the first
1199 three records, call:
1201 my ($one, $two, $three) = $rs->slice(0, 2);
1206 my ($self, $min, $max) = @_;
1207 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1208 $attrs->{offset} = $self->{attrs}{offset} || 0;
1209 $attrs->{offset} += $min;
1210 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1211 return $self->search(undef, $attrs);
1212 #my $slice = (ref $self)->new($self->result_source, $attrs);
1213 #return (wantarray ? $slice->all : $slice);
1220 =item Arguments: none
1222 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1226 Returns the next element in the resultset (C<undef> is there is none).
1228 Can be used to efficiently iterate over records in the resultset:
1230 my $rs = $schema->resultset('CD')->search;
1231 while (my $cd = $rs->next) {
1235 Note that you need to store the resultset object, and call C<next> on it.
1236 Calling C<< resultset('Table')->next >> repeatedly will always return the
1237 first record from the resultset.
1244 if (my $cache = $self->get_cache) {
1245 $self->{all_cache_position} ||= 0;
1246 return $cache->[$self->{all_cache_position}++];
1249 if ($self->{attrs}{cache}) {
1250 delete $self->{pager};
1251 $self->{all_cache_position} = 1;
1252 return ($self->all)[0];
1255 return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
1257 $self->{_stashed_results} = $self->_construct_results
1260 return shift @{$self->{_stashed_results}};
1263 # Constructs as many results as it can in one pass while respecting
1264 # cursor laziness. Several modes of operation:
1266 # * Always builds everything present in @{$self->{_stashed_rows}}
1267 # * If called with $fetch_all true - pulls everything off the cursor and
1268 # builds all result structures (or objects) in one pass
1269 # * If $self->_resolved_attrs->{collapse} is true, checks the order_by
1270 # and if the resultset is ordered properly by the left side:
1271 # * Fetches stuff off the cursor until the "master object" changes,
1272 # and saves the last extra row (if any) in @{$self->{_stashed_rows}}
1274 # * Just fetches, and collapses/constructs everything as if $fetch_all
1275 # was requested (there is no other way to collapse except for an
1277 # * If no collapse is requested - just get the next row, construct and
1279 sub _construct_results {
1280 my ($self, $fetch_all) = @_;
1282 my $rsrc = $self->result_source;
1283 my $attrs = $self->_resolved_attrs;
1288 ! $attrs->{order_by}
1292 my @pcols = $rsrc->primary_columns
1294 # default order for collapsing unless the user asked for something
1295 $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
1296 $attrs->{_ordered_for_collapse} = 1;
1297 $attrs->{_order_is_artificial} = 1;
1300 my $cursor = $self->cursor;
1302 # this will be used as both initial raw-row collector AND as a RV of
1303 # _construct_results. Not regrowing the array twice matters a lot...
1304 # a surprising amount actually
1305 my $rows = delete $self->{_stashed_rows};
1307 my $did_fetch_all = $fetch_all;
1310 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1311 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1313 elsif( $attrs->{collapse} ) {
1315 $attrs->{_ordered_for_collapse} = (!$attrs->{order_by}) ? 0 : do {
1316 my $st = $rsrc->schema->storage;
1319 ( $st->_extract_order_criteria($attrs->{order_by}) )
1322 my $colinfos = $st->_resolve_column_info($attrs->{from}, \@ord_cols);
1324 for (0 .. $#ord_cols) {
1326 ! $colinfos->{$ord_cols[$_]}
1328 $colinfos->{$ord_cols[$_]}{-result_source} != $rsrc
1330 splice @ord_cols, $_;
1335 # since all we check here are the start of the order_by belonging to the
1336 # top level $rsrc, a present identifying set will mean that the resultset
1337 # is ordered by its leftmost table in a tsable manner
1338 (@ord_cols and $rsrc->_identifying_column_set({ map
1339 { $colinfos->{$_}{-colname} => $colinfos->{$_} }
1342 } unless defined $attrs->{_ordered_for_collapse};
1344 if (! $attrs->{_ordered_for_collapse}) {
1347 # instead of looping over ->next, use ->all in stealth mode
1348 # *without* calling a ->reset afterwards
1349 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1350 if (! $cursor->{_done}) {
1351 $rows = [ ($rows ? @$rows : ()), $cursor->all ];
1352 $cursor->{_done} = 1;
1357 if (! $did_fetch_all and ! @{$rows||[]} ) {
1358 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1359 if (scalar (my @r = $cursor->next) ) {
1364 return undef unless @{$rows||[]};
1366 my @extra_collapser_args;
1367 if ($attrs->{collapse} and ! $did_fetch_all ) {
1369 @extra_collapser_args = (
1370 # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
1371 sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
1372 ($self->{_stashed_rows} = []), # where does it stuff excess
1376 # hotspot - skip the setter
1377 my $res_class = $self->_result_class;
1379 my $inflator_cref = $self->{_result_inflator}{cref} ||= do {
1380 $res_class->can ('inflate_result')
1381 or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method");
1384 my $infmap = $attrs->{as};
1387 $self->{_result_inflator}{is_core_row} = ( (
1390 ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
1391 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
1393 $self->{_result_inflator}{is_hri} = ( (
1394 ! $self->{_result_inflator}{is_core_row}
1397 require DBIx::Class::ResultClass::HashRefInflator
1399 DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
1401 ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
1404 if (! $attrs->{_related_results_construction}) {
1405 # construct a much simpler array->hash folder for the one-table cases right here
1406 if ($self->{_result_inflator}{is_hri}) {
1407 for my $r (@$rows) {
1408 $r = { map { $infmap->[$_] => $r->[$_] } 0..$#$infmap };
1411 # FIXME SUBOPTIMAL this is a very very very hot spot
1412 # while rather optimal we can *still* do much better, by
1413 # building a smarter Row::inflate_result(), and
1414 # switch to feeding it data via a much leaner interface
1416 # crude unscientific benchmarking indicated the shortcut eval is not worth it for
1417 # this particular resultset size
1418 elsif (@$rows < 60) {
1419 for my $r (@$rows) {
1420 $r = $inflator_cref->($res_class, $rsrc, { map { $infmap->[$_] => $r->[$_] } (0..$#$infmap) } );
1425 '$_ = $inflator_cref->($res_class, $rsrc, { %s }) for @$rows',
1426 join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap )
1430 # Special-case multi-object HRI (we always prune, and there is no $inflator_cref pass)
1431 elsif ($self->{_result_inflator}{is_hri}) {
1432 ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
1434 inflate_map => $infmap,
1435 selection => $attrs->{select},
1436 collapse => $attrs->{collapse},
1437 premultiplied => $attrs->{_main_source_premultiplied},
1439 prune_null_branches => 1,
1440 }) )->($rows, @extra_collapser_args);
1442 # Regular multi-object
1444 my $parser_type = $self->{_result_inflator}{is_core_row} ? 'classic_pruning' : 'classic_nonpruning';
1446 ( $self->{_row_parser}{$parser_type} ||= $rsrc->_mk_row_parser({
1448 inflate_map => $infmap,
1449 selection => $attrs->{select},
1450 collapse => $attrs->{collapse},
1451 premultiplied => $attrs->{_main_source_premultiplied},
1452 prune_null_branches => $self->{_result_inflator}{is_core_row},
1453 }) )->($rows, @extra_collapser_args);
1455 $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
1458 # The @$rows check seems odd at first - why wouldn't we want to warn
1459 # regardless? The issue is things like find() etc, where the user
1460 # *knows* only one result will come back. In these cases the ->all
1461 # is not a pessimization, but rather something we actually want
1463 'Unable to properly collapse has_many results in iterator mode due '
1464 . 'to order criteria - performed an eager cursor slurp underneath. '
1465 . 'Consider using ->all() instead'
1466 ) if ( ! $fetch_all and @$rows > 1 );
1471 =head2 result_source
1475 =item Arguments: L<$result_source?|DBIx::Class::ResultSource>
1477 =item Return Value: L<$result_source|DBIx::Class::ResultSource>
1481 An accessor for the primary ResultSource object from which this ResultSet
1488 =item Arguments: $result_class?
1490 =item Return Value: $result_class
1494 An accessor for the class to use when creating result objects. Defaults to
1495 C<< result_source->result_class >> - which in most cases is the name of the
1496 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1498 Note that changing the result_class will also remove any components
1499 that were originally loaded in the source class via
1500 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1501 in the original source class will not run.
1506 my ($self, $result_class) = @_;
1507 if ($result_class) {
1509 # don't fire this for an object
1510 $self->ensure_class_loaded($result_class)
1511 unless ref($result_class);
1513 if ($self->get_cache) {
1514 carp_unique('Changing the result_class of a ResultSet instance with cached results is a noop - the cache contents will not be altered');
1516 # FIXME ENCAPSULATION - encapsulation breach, cursor method additions pending
1517 elsif ($self->{cursor} && $self->{cursor}{_pos}) {
1518 $self->throw_exception('Changing the result_class of a ResultSet instance with an active cursor is not supported');
1521 $self->_result_class($result_class);
1523 delete $self->{_result_inflator};
1525 $self->_result_class;
1532 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1534 =item Return Value: $count
1538 Performs an SQL C<COUNT> with the same query as the resultset was built
1539 with to find the number of elements. Passing arguments is equivalent to
1540 C<< $rs->search ($cond, \%attrs)->count >>
1546 return $self->search(@_)->count if @_ and defined $_[0];
1547 return scalar @{ $self->get_cache } if $self->get_cache;
1549 my $attrs = { %{ $self->_resolved_attrs } };
1551 # this is a little optimization - it is faster to do the limit
1552 # adjustments in software, instead of a subquery
1553 my ($rows, $offset) = delete @{$attrs}{qw/rows offset/};
1556 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1557 $crs = $self->_count_subq_rs ($attrs);
1560 $crs = $self->_count_rs ($attrs);
1562 my $count = $crs->next;
1564 $count -= $offset if $offset;
1565 $count = $rows if $rows and $rows < $count;
1566 $count = 0 if ($count < 0);
1575 =item Arguments: L<$cond|DBIx::Class::SQLMaker>, L<\%attrs?|/ATTRIBUTES>
1577 =item Return Value: L<$count_rs|DBIx::Class::ResultSetColumn>
1581 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1582 This can be very handy for subqueries:
1584 ->search( { amount => $some_rs->count_rs->as_query } )
1586 As with regular resultsets the SQL query will be executed only after
1587 the resultset is accessed via L</next> or L</all>. That would return
1588 the same single value obtainable via L</count>.
1594 return $self->search(@_)->count_rs if @_;
1596 # this may look like a lack of abstraction (count() does about the same)
1597 # but in fact an _rs *must* use a subquery for the limits, as the
1598 # software based limiting can not be ported if this $rs is to be used
1599 # in a subquery itself (i.e. ->as_query)
1600 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1601 return $self->_count_subq_rs;
1604 return $self->_count_rs;
1609 # returns a ResultSetColumn object tied to the count query
1612 my ($self, $attrs) = @_;
1614 my $rsrc = $self->result_source;
1615 $attrs ||= $self->_resolved_attrs;
1617 my $tmp_attrs = { %$attrs };
1618 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1619 delete @{$tmp_attrs}{qw/rows offset order_by _related_results_construction record_filter for/};
1621 # overwrite the selector (supplied by the storage)
1622 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1623 $tmp_attrs->{as} = 'count';
1625 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1631 # same as above but uses a subquery
1633 sub _count_subq_rs {
1634 my ($self, $attrs) = @_;
1636 my $rsrc = $self->result_source;
1637 $attrs ||= $self->_resolved_attrs;
1639 my $sub_attrs = { %$attrs };
1640 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1641 delete @{$sub_attrs}{qw/collapse columns as select _related_results_construction order_by for/};
1643 # if we multi-prefetch we group_by something unique, as this is what we would
1644 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1645 if ( $attrs->{collapse} ) {
1646 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{
1647 $rsrc->_identifying_column_set || $self->throw_exception(
1648 'Unable to construct a unique group_by criteria properly collapsing the '
1649 . 'has_many prefetch before count()'
1654 # Calculate subquery selector
1655 if (my $g = $sub_attrs->{group_by}) {
1657 my $sql_maker = $rsrc->storage->sql_maker;
1659 # necessary as the group_by may refer to aliased functions
1661 for my $sel (@{$attrs->{select}}) {
1662 $sel_index->{$sel->{-as}} = $sel
1663 if (ref $sel eq 'HASH' and $sel->{-as});
1666 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1667 # also look for named aggregates referred in the having clause
1668 # having often contains scalarrefs - thus parse it out entirely
1670 if ($attrs->{having}) {
1671 local $sql_maker->{having_bind};
1672 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1673 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1674 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1675 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1676 # if we don't unset it we screw up retarded but unfortunately working
1677 # 'MAX(foo.bar)' => { '>', 3 }
1678 $sql_maker->{name_sep} = '';
1681 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1683 my $having_sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1686 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1687 # and if all fails for an utterly naive quoted scalar-with-function
1688 while ($having_sql =~ /
1689 $rquote $sep $lquote (.+?) $rquote
1691 [\s,] \w+ \. (\w+) [\s,]
1693 [\s,] $lquote (.+?) $rquote [\s,]
1695 my $part = $1 || $2 || $3; # one of them matched if we got here
1696 unless ($seen_having{$part}++) {
1703 my $colpiece = $sel_index->{$_} || $_;
1705 # unqualify join-based group_by's. Arcane but possible query
1706 # also horrible horrible hack to alias a column (not a func.)
1707 # (probably need to introduce SQLA syntax)
1708 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1711 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1713 push @{$sub_attrs->{select}}, $colpiece;
1717 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1718 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1721 return $rsrc->resultset_class
1722 ->new ($rsrc, $sub_attrs)
1724 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1725 ->get_column ('count');
1729 =head2 count_literal
1731 B<CAVEAT>: C<count_literal> is provided for Class::DBI compatibility and
1732 should only be used in that context. See L</search_literal> for further info.
1736 =item Arguments: $sql_fragment, @standalone_bind_values
1738 =item Return Value: $count
1742 Counts the results in a literal query. Equivalent to calling L</search_literal>
1743 with the passed arguments, then L</count>.
1747 sub count_literal { shift->search_literal(@_)->count; }
1753 =item Arguments: none
1755 =item Return Value: L<@result_objs|DBIx::Class::Manual::ResultClass>
1759 Returns all elements in the resultset.
1766 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1769 delete @{$self}{qw/_stashed_rows _stashed_results/};
1771 if (my $c = $self->get_cache) {
1775 $self->cursor->reset;
1777 my $objs = $self->_construct_results('fetch_all') || [];
1779 $self->set_cache($objs) if $self->{attrs}{cache};
1788 =item Arguments: none
1790 =item Return Value: $self
1794 Resets the resultset's cursor, so you can iterate through the elements again.
1795 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1803 delete @{$self}{qw/_stashed_rows _stashed_results/};
1804 $self->{all_cache_position} = 0;
1805 $self->cursor->reset;
1813 =item Arguments: none
1815 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass> | undef
1819 L<Resets|/reset> the resultset (causing a fresh query to storage) and returns
1820 an object for the first result (or C<undef> if the resultset is empty).
1825 return $_[0]->reset->next;
1831 # Determines whether and what type of subquery is required for the $rs operation.
1832 # If grouping is necessary either supplies its own, or verifies the current one
1833 # After all is done delegates to the proper storage method.
1835 sub _rs_update_delete {
1836 my ($self, $op, $values) = @_;
1838 my $rsrc = $self->result_source;
1839 my $storage = $rsrc->schema->storage;
1841 my $attrs = { %{$self->_resolved_attrs} };
1843 my $join_classifications;
1844 my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
1846 # do we need a subquery for any reason?
1848 defined $existing_group_by
1850 # if {from} is unparseable wrap a subq
1851 ref($attrs->{from}) ne 'ARRAY'
1853 # limits call for a subq
1854 $self->_has_resolved_attr(qw/rows offset/)
1857 # simplify the joinmap, so we can further decide if a subq is necessary
1858 if (!$needs_subq and @{$attrs->{from}} > 1) {
1859 $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
1861 # check if there are any joins left after the prune
1862 if ( @{$attrs->{from}} > 1 ) {
1863 $join_classifications = $storage->_resolve_aliastypes_from_select_args (
1864 [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
1870 # any non-pruneable joins imply subq
1871 $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
1875 # check if the head is composite (by now all joins are thrown out unless $needs_subq)
1877 (ref $attrs->{from}[0]) ne 'HASH'
1879 ref $attrs->{from}[0]{ $attrs->{from}[0]{-alias} }
1883 # do we need anything like a subquery?
1884 if (! $needs_subq) {
1885 # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus
1886 # a condition containing 'me' or other table prefixes will not work
1887 # at all. Tell SQLMaker to dequalify idents via a gross hack.
1889 my $sqla = $rsrc->storage->sql_maker;
1890 local $sqla->{_dequalify_idents} = 1;
1891 \[ $sqla->_recurse_where($self->{cond}) ];
1895 # we got this far - means it is time to wrap a subquery
1896 my $idcols = $rsrc->_identifying_column_set || $self->throw_exception(
1898 "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'",
1904 # make a new $rs selecting only the PKs (that's all we really need for the subq)
1905 delete $attrs->{$_} for qw/select as collapse _related_results_construction/;
1906 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ];
1907 $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins
1908 my $subrs = (ref $self)->new($rsrc, $attrs);
1910 if (@$idcols == 1) {
1911 $cond = { $idcols->[0] => { -in => $subrs->as_query } };
1913 elsif ($storage->_use_multicolumn_in) {
1914 # no syntax for calling this properly yet
1915 # !!! EXPERIMENTAL API !!! WILL CHANGE !!!
1916 $cond = $storage->sql_maker->_where_op_multicolumn_in (
1917 $idcols, # how do I convey a list of idents...? can binds reside on lhs?
1922 # if all else fails - get all primary keys and operate over a ORed set
1923 # wrap in a transaction for consistency
1924 # this is where the group_by/multiplication starts to matter
1928 keys %{ $join_classifications->{multiplying} || {} }
1930 # make sure if there is a supplied group_by it matches the columns compiled above
1931 # perfectly. Anything else can not be sanely executed on most databases so croak
1932 # right then and there
1933 if ($existing_group_by) {
1934 my @current_group_by = map
1935 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1940 join ("\x00", sort @current_group_by)
1942 join ("\x00", sort @{$attrs->{columns}} )
1944 $self->throw_exception (
1945 "You have just attempted a $op operation on a resultset which does group_by"
1946 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1947 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1948 . ' kind of queries. Please retry the operation with a modified group_by or'
1949 . ' without using one at all.'
1954 $subrs = $subrs->search({}, { group_by => $attrs->{columns} });
1957 $guard = $storage->txn_scope_guard;
1960 for my $row ($subrs->cursor->all) {
1962 { $idcols->[$_] => $row->[$_] }
1969 my $res = $storage->$op (
1971 $op eq 'update' ? $values : (),
1975 $guard->commit if $guard;
1984 =item Arguments: \%values
1986 =item Return Value: $underlying_storage_rv
1990 Sets the specified columns in the resultset to the supplied values in a
1991 single query. Note that this will not run any accessor/set_column/update
1992 triggers, nor will it update any result object instances derived from this
1993 resultset (this includes the contents of the L<resultset cache|/set_cache>
1994 if any). See L</update_all> if you need to execute any on-update
1995 triggers or cascades defined either by you or a
1996 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
1998 The return value is a pass through of what the underlying
1999 storage backend returned, and may vary. See L<DBI/execute> for the most
2004 Note that L</update> does not process/deflate any of the values passed in.
2005 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
2006 ensure manually that any value passed to this method will stringify to
2007 something the RDBMS knows how to deal with. A notable example is the
2008 handling of L<DateTime> objects, for more info see:
2009 L<DBIx::Class::Manual::Cookbook/Formatting DateTime objects in queries>.
2014 my ($self, $values) = @_;
2015 $self->throw_exception('Values for update must be a hash')
2016 unless ref $values eq 'HASH';
2018 return $self->_rs_update_delete ('update', $values);
2025 =item Arguments: \%values
2027 =item Return Value: 1
2031 Fetches all objects and updates them one at a time via
2032 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
2033 triggers, while L</update> will not.
2038 my ($self, $values) = @_;
2039 $self->throw_exception('Values for update_all must be a hash')
2040 unless ref $values eq 'HASH';
2042 my $guard = $self->result_source->schema->txn_scope_guard;
2043 $_->update({%$values}) for $self->all; # shallow copy - update will mangle it
2052 =item Arguments: none
2054 =item Return Value: $underlying_storage_rv
2058 Deletes the rows matching this resultset in a single query. Note that this
2059 will not run any delete triggers, nor will it alter the
2060 L<in_storage|DBIx::Class::Row/in_storage> status of any result object instances
2061 derived from this resultset (this includes the contents of the
2062 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
2063 execute any on-delete triggers or cascades defined either by you or a
2064 L<result component|DBIx::Class::Manual::Component/WHAT IS A COMPONENT>.
2066 The return value is a pass through of what the underlying storage backend
2067 returned, and may vary. See L<DBI/execute> for the most common case.
2073 $self->throw_exception('delete does not accept any arguments')
2076 return $self->_rs_update_delete ('delete');
2083 =item Arguments: none
2085 =item Return Value: 1
2089 Fetches all objects and deletes them one at a time via
2090 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
2091 triggers, while L</delete> will not.
2097 $self->throw_exception('delete_all does not accept any arguments')
2100 my $guard = $self->result_source->schema->txn_scope_guard;
2101 $_->delete for $self->all;
2110 =item Arguments: [ \@column_list, \@row_values+ ] | [ \%col_data+ ]
2112 =item Return Value: L<\@result_objects|DBIx::Class::Manual::ResultClass> (scalar context) | L<@result_objects|DBIx::Class::Manual::ResultClass> (list context)
2116 Accepts either an arrayref of hashrefs or alternatively an arrayref of
2123 The context of this method call has an important effect on what is
2124 submitted to storage. In void context data is fed directly to fastpath
2125 insertion routines provided by the underlying storage (most often
2126 L<DBI/execute_for_fetch>), bypassing the L<new|DBIx::Class::Row/new> and
2127 L<insert|DBIx::Class::Row/insert> calls on the
2128 L<Result|DBIx::Class::Manual::ResultClass> class, including any
2129 augmentation of these methods provided by components. For example if you
2130 are using something like L<DBIx::Class::UUIDColumns> to create primary
2131 keys for you, you will find that your PKs are empty. In this case you
2132 will have to explicitly force scalar or list context in order to create
2137 In non-void (scalar or list) context, this method is simply a wrapper
2138 for L</create>. Depending on list or scalar context either a list of
2139 L<Result|DBIx::Class::Manual::ResultClass> objects or an arrayref
2140 containing these objects is returned.
2142 When supplying data in "arrayref of arrayrefs" invocation style, the
2143 first element should be a list of column names and each subsequent
2144 element should be a data value in the earlier specified column order.
2147 $Arstist_rs->populate([
2148 [ qw( artistid name ) ],
2149 [ 100, 'A Formally Unknown Singer' ],
2150 [ 101, 'A singer that jumped the shark two albums ago' ],
2151 [ 102, 'An actually cool singer' ],
2154 For the arrayref of hashrefs style each hashref should be a structure
2155 suitable for passing to L</create>. Multi-create is also permitted with
2158 $schema->resultset("Artist")->populate([
2159 { artistid => 4, name => 'Manufactured Crap', cds => [
2160 { title => 'My First CD', year => 2006 },
2161 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2164 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
2165 { title => 'My parents sold me to a record company', year => 2005 },
2166 { title => 'Why Am I So Ugly?', year => 2006 },
2167 { title => 'I Got Surgery and am now Popular', year => 2007 }
2172 If you attempt a void-context multi-create as in the example above (each
2173 Artist also has the related list of CDs), and B<do not> supply the
2174 necessary autoinc foreign key information, this method will proxy to the
2175 less efficient L</create>, and then throw the Result objects away. In this
2176 case there are obviously no benefits to using this method over L</create>.
2183 # cruft placed in standalone method
2184 my $data = $self->_normalize_populate_args(@_);
2186 return unless @$data;
2188 if(defined wantarray) {
2189 my @created = map { $self->create($_) } @$data;
2190 return wantarray ? @created : \@created;
2193 my $first = $data->[0];
2195 # if a column is a registered relationship, and is a non-blessed hash/array, consider
2196 # it relationship data
2197 my (@rels, @columns);
2198 my $rsrc = $self->result_source;
2199 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
2200 for (keys %$first) {
2201 my $ref = ref $first->{$_};
2202 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
2208 my @pks = $rsrc->primary_columns;
2210 ## do the belongs_to relationships
2211 foreach my $index (0..$#$data) {
2213 # delegate to create() for any dataset without primary keys with specified relationships
2214 if (grep { !defined $data->[$index]->{$_} } @pks ) {
2216 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
2217 my @ret = $self->populate($data);
2223 foreach my $rel (@rels) {
2224 next unless ref $data->[$index]->{$rel} eq "HASH";
2225 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
2226 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
2227 my $related = $result->result_source->_resolve_condition(
2228 $reverse_relinfo->{cond},
2234 delete $data->[$index]->{$rel};
2235 $data->[$index] = {%{$data->[$index]}, %$related};
2237 push @columns, keys %$related if $index == 0;
2241 ## inherit the data locked in the conditions of the resultset
2242 my ($rs_data) = $self->_merge_with_rscond({});
2243 delete @{$rs_data}{@columns};
2245 ## do bulk insert on current row
2246 $rsrc->storage->insert_bulk(
2248 [@columns, keys %$rs_data],
2249 [ map { [ @$_{@columns}, values %$rs_data ] } @$data ],
2252 ## do the has_many relationships
2253 foreach my $item (@$data) {
2257 foreach my $rel (@rels) {
2258 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
2260 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
2262 my $child = $main_row->$rel;
2264 my $related = $child->result_source->_resolve_condition(
2265 $rels->{$rel}{cond},
2271 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2272 my @populate = map { {%$_, %$related} } @rows_to_add;
2274 $child->populate( \@populate );
2281 # populate() argumnets went over several incarnations
2282 # What we ultimately support is AoH
2283 sub _normalize_populate_args {
2284 my ($self, $arg) = @_;
2286 if (ref $arg eq 'ARRAY') {
2290 elsif (ref $arg->[0] eq 'HASH') {
2293 elsif (ref $arg->[0] eq 'ARRAY') {
2295 my @colnames = @{$arg->[0]};
2296 foreach my $values (@{$arg}[1 .. $#$arg]) {
2297 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2303 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2310 =item Arguments: none
2312 =item Return Value: L<$pager|Data::Page>
2316 Returns a L<Data::Page> object for the current resultset. Only makes
2317 sense for queries with a C<page> attribute.
2319 To get the full count of entries for a paged resultset, call
2320 C<total_entries> on the L<Data::Page> object.
2327 return $self->{pager} if $self->{pager};
2329 my $attrs = $self->{attrs};
2330 if (!defined $attrs->{page}) {
2331 $self->throw_exception("Can't create pager for non-paged rs");
2333 elsif ($attrs->{page} <= 0) {
2334 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2336 $attrs->{rows} ||= 10;
2338 # throw away the paging flags and re-run the count (possibly
2339 # with a subselect) to get the real total count
2340 my $count_attrs = { %$attrs };
2341 delete @{$count_attrs}{qw/rows offset page pager/};
2343 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2345 require DBIx::Class::ResultSet::Pager;
2346 return $self->{pager} = DBIx::Class::ResultSet::Pager->new(
2347 sub { $total_rs->count }, #lazy-get the total
2349 $self->{attrs}{page},
2357 =item Arguments: $page_number
2359 =item Return Value: L<$resultset|/search>
2363 Returns a resultset for the $page_number page of the resultset on which page
2364 is called, where each page contains a number of rows equal to the 'rows'
2365 attribute set on the resultset (10 by default).
2370 my ($self, $page) = @_;
2371 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2378 =item Arguments: \%col_data
2380 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2384 Creates a new result object in the resultset's result class and returns
2385 it. The row is not inserted into the database at this point, call
2386 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2387 will tell you whether the result object has been inserted or not.
2389 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2394 my ($self, $values) = @_;
2396 $self->throw_exception( "new_result takes only one argument - a hashref of values" )
2399 $self->throw_exception( "new_result expects a hashref" )
2400 unless (ref $values eq 'HASH');
2402 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2404 my $new = $self->result_class->new({
2406 ( @$cols_from_relations
2407 ? (-cols_from_relations => $cols_from_relations)
2410 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2414 reftype($new) eq 'HASH'
2420 carp_unique (sprintf (
2421 "%s->new returned a blessed empty hashref - a strong indicator something is wrong with its inheritance chain",
2422 $self->result_class,
2429 # _merge_with_rscond
2431 # Takes a simple hash of K/V data and returns its copy merged with the
2432 # condition already present on the resultset. Additionally returns an
2433 # arrayref of value/condition names, which were inferred from related
2434 # objects (this is needed for in-memory related objects)
2435 sub _merge_with_rscond {
2436 my ($self, $data) = @_;
2438 my (%new_data, @cols_from_relations);
2440 my $alias = $self->{attrs}{alias};
2442 if (! defined $self->{cond}) {
2443 # just massage $data below
2445 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2446 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2447 @cols_from_relations = keys %new_data;
2449 elsif (ref $self->{cond} ne 'HASH') {
2450 $self->throw_exception(
2451 "Can't abstract implicit construct, resultset condition not a hash"
2455 # precendence must be given to passed values over values inherited from
2456 # the cond, so the order here is important.
2457 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2458 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2460 while ( my($col, $value) = each %implied ) {
2461 my $vref = ref $value;
2467 (keys %$value)[0] eq '='
2469 $new_data{$col} = $value->{'='};
2471 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2472 $new_data{$col} = $value;
2479 %{ $self->_remove_alias($data, $alias) },
2482 return (\%new_data, \@cols_from_relations);
2485 # _has_resolved_attr
2487 # determines if the resultset defines at least one
2488 # of the attributes supplied
2490 # used to determine if a subquery is neccessary
2492 # supports some virtual attributes:
2494 # This will scan for any joins being present on the resultset.
2495 # It is not a mere key-search but a deep inspection of {from}
2498 sub _has_resolved_attr {
2499 my ($self, @attr_names) = @_;
2501 my $attrs = $self->_resolved_attrs;
2505 for my $n (@attr_names) {
2506 if (grep { $n eq $_ } (qw/-join/) ) {
2507 $extra_checks{$n}++;
2511 my $attr = $attrs->{$n};
2513 next if not defined $attr;
2515 if (ref $attr eq 'HASH') {
2516 return 1 if keys %$attr;
2518 elsif (ref $attr eq 'ARRAY') {
2526 # a resolved join is expressed as a multi-level from
2528 $extra_checks{-join}
2530 ref $attrs->{from} eq 'ARRAY'
2532 @{$attrs->{from}} > 1
2540 # Recursively collapse the condition.
2542 sub _collapse_cond {
2543 my ($self, $cond, $collapsed) = @_;
2547 if (ref $cond eq 'ARRAY') {
2548 foreach my $subcond (@$cond) {
2549 next unless ref $subcond; # -or
2550 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2553 elsif (ref $cond eq 'HASH') {
2554 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2555 foreach my $subcond (@{$cond->{-and}}) {
2556 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2560 foreach my $col (keys %$cond) {
2561 my $value = $cond->{$col};
2562 $collapsed->{$col} = $value;
2572 # Remove the specified alias from the specified query hash. A copy is made so
2573 # the original query is not modified.
2576 my ($self, $query, $alias) = @_;
2578 my %orig = %{ $query || {} };
2581 foreach my $key (keys %orig) {
2583 $unaliased{$key} = $orig{$key};
2586 $unaliased{$1} = $orig{$key}
2587 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2597 =item Arguments: none
2599 =item Return Value: \[ $sql, L<@bind_values|/DBIC BIND VALUES> ]
2603 Returns the SQL query and bind vars associated with the invocant.
2605 This is generally used as the RHS for a subquery.
2612 my $attrs = { %{ $self->_resolved_attrs } };
2614 $self->result_source->storage->_select_args_to_query (
2615 $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
2623 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2625 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2629 my $artist = $schema->resultset('Artist')->find_or_new(
2630 { artist => 'fred' }, { key => 'artists' });
2632 $cd->cd_to_producer->find_or_new({ producer => $producer },
2633 { key => 'primary });
2635 Find an existing record from this resultset using L</find>. if none exists,
2636 instantiate a new result object and return it. The object will not be saved
2637 into your storage until you call L<DBIx::Class::Row/insert> on it.
2639 You most likely want this method when looking for existing rows using a unique
2640 constraint that is not the primary key, or looking for related rows.
2642 If you want objects to be saved immediately, use L</find_or_create> instead.
2644 B<Note>: Make sure to read the documentation of L</find> and understand the
2645 significance of the C<key> attribute, as its lack may skew your search, and
2646 subsequently result in spurious new objects.
2648 B<Note>: Take care when using C<find_or_new> with a table having
2649 columns with default values that you intend to be automatically
2650 supplied by the database (e.g. an auto_increment primary key column).
2651 In normal usage, the value of such columns should NOT be included at
2652 all in the call to C<find_or_new>, even when set to C<undef>.
2658 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2659 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2660 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2663 return $self->new_result($hash);
2670 =item Arguments: \%col_data
2672 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2676 Attempt to create a single new row or a row with multiple related rows
2677 in the table represented by the resultset (and related tables). This
2678 will not check for duplicate rows before inserting, use
2679 L</find_or_create> to do that.
2681 To create one row for this resultset, pass a hashref of key/value
2682 pairs representing the columns of the table and the values you wish to
2683 store. If the appropriate relationships are set up, foreign key fields
2684 can also be passed an object representing the foreign row, and the
2685 value will be set to its primary key.
2687 To create related objects, pass a hashref of related-object column values
2688 B<keyed on the relationship name>. If the relationship is of type C<multi>
2689 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2690 The process will correctly identify columns holding foreign keys, and will
2691 transparently populate them from the keys of the corresponding relation.
2692 This can be applied recursively, and will work correctly for a structure
2693 with an arbitrary depth and width, as long as the relationships actually
2694 exists and the correct column data has been supplied.
2696 Instead of hashrefs of plain related data (key/value pairs), you may
2697 also pass new or inserted objects. New objects (not inserted yet, see
2698 L</new_result>), will be inserted into their appropriate tables.
2700 Effectively a shortcut for C<< ->new_result(\%col_data)->insert >>.
2702 Example of creating a new row.
2704 $person_rs->create({
2705 name=>"Some Person",
2706 email=>"somebody@someplace.com"
2709 Example of creating a new row and also creating rows in a related C<has_many>
2710 or C<has_one> resultset. Note Arrayref.
2713 { artistid => 4, name => 'Manufactured Crap', cds => [
2714 { title => 'My First CD', year => 2006 },
2715 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2720 Example of creating a new row and also creating a row in a related
2721 C<belongs_to> resultset. Note Hashref.
2724 title=>"Music for Silly Walks",
2727 name=>"Silly Musician",
2735 When subclassing ResultSet never attempt to override this method. Since
2736 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2737 lot of the internals simply never call it, so your override will be
2738 bypassed more often than not. Override either L<DBIx::Class::Row/new>
2739 or L<DBIx::Class::Row/insert> depending on how early in the
2740 L</create> process you need to intervene. See also warning pertaining to
2748 my ($self, $col_data) = @_;
2749 $self->throw_exception( "create needs a hashref" )
2750 unless ref $col_data eq 'HASH';
2751 return $self->new_result($col_data)->insert;
2754 =head2 find_or_create
2758 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2760 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2764 $cd->cd_to_producer->find_or_create({ producer => $producer },
2765 { key => 'primary' });
2767 Tries to find a record based on its primary key or unique constraints; if none
2768 is found, creates one and returns that instead.
2770 my $cd = $schema->resultset('CD')->find_or_create({
2772 artist => 'Massive Attack',
2773 title => 'Mezzanine',
2777 Also takes an optional C<key> attribute, to search by a specific key or unique
2778 constraint. For example:
2780 my $cd = $schema->resultset('CD')->find_or_create(
2782 artist => 'Massive Attack',
2783 title => 'Mezzanine',
2785 { key => 'cd_artist_title' }
2788 B<Note>: Make sure to read the documentation of L</find> and understand the
2789 significance of the C<key> attribute, as its lack may skew your search, and
2790 subsequently result in spurious row creation.
2792 B<Note>: Because find_or_create() reads from the database and then
2793 possibly inserts based on the result, this method is subject to a race
2794 condition. Another process could create a record in the table after
2795 the find has completed and before the create has started. To avoid
2796 this problem, use find_or_create() inside a transaction.
2798 B<Note>: Take care when using C<find_or_create> with a table having
2799 columns with default values that you intend to be automatically
2800 supplied by the database (e.g. an auto_increment primary key column).
2801 In normal usage, the value of such columns should NOT be included at
2802 all in the call to C<find_or_create>, even when set to C<undef>.
2804 See also L</find> and L</update_or_create>. For information on how to declare
2805 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2807 If you need to know if an existing row was found or a new one created use
2808 L</find_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2809 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2812 my $cd = $schema->resultset('CD')->find_or_new({
2814 artist => 'Massive Attack',
2815 title => 'Mezzanine',
2819 if( !$cd->in_storage ) {
2826 sub find_or_create {
2828 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2829 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2830 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2833 return $self->create($hash);
2836 =head2 update_or_create
2840 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2842 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2846 $resultset->update_or_create({ col => $val, ... });
2848 Like L</find_or_create>, but if a row is found it is immediately updated via
2849 C<< $found_row->update (\%col_data) >>.
2852 Takes an optional C<key> attribute to search on a specific unique constraint.
2855 # In your application
2856 my $cd = $schema->resultset('CD')->update_or_create(
2858 artist => 'Massive Attack',
2859 title => 'Mezzanine',
2862 { key => 'cd_artist_title' }
2865 $cd->cd_to_producer->update_or_create({
2866 producer => $producer,
2872 B<Note>: Make sure to read the documentation of L</find> and understand the
2873 significance of the C<key> attribute, as its lack may skew your search, and
2874 subsequently result in spurious row creation.
2876 B<Note>: Take care when using C<update_or_create> with a table having
2877 columns with default values that you intend to be automatically
2878 supplied by the database (e.g. an auto_increment primary key column).
2879 In normal usage, the value of such columns should NOT be included at
2880 all in the call to C<update_or_create>, even when set to C<undef>.
2882 See also L</find> and L</find_or_create>. For information on how to declare
2883 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2885 If you need to know if an existing row was updated or a new one created use
2886 L</update_or_new> and L<DBIx::Class::Row/in_storage> instead. Don't forget
2887 to call L<DBIx::Class::Row/insert> to save the newly created row to the
2892 sub update_or_create {
2894 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2895 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2897 my $row = $self->find($cond, $attrs);
2899 $row->update($cond);
2903 return $self->create($cond);
2906 =head2 update_or_new
2910 =item Arguments: \%col_data, { key => $unique_constraint, L<%attrs|/ATTRIBUTES> }?
2912 =item Return Value: L<$result|DBIx::Class::Manual::ResultClass>
2916 $resultset->update_or_new({ col => $val, ... });
2918 Like L</find_or_new> but if a row is found it is immediately updated via
2919 C<< $found_row->update (\%col_data) >>.
2923 # In your application
2924 my $cd = $schema->resultset('CD')->update_or_new(
2926 artist => 'Massive Attack',
2927 title => 'Mezzanine',
2930 { key => 'cd_artist_title' }
2933 if ($cd->in_storage) {
2934 # the cd was updated
2937 # the cd is not yet in the database, let's insert it
2941 B<Note>: Make sure to read the documentation of L</find> and understand the
2942 significance of the C<key> attribute, as its lack may skew your search, and
2943 subsequently result in spurious new objects.
2945 B<Note>: Take care when using C<update_or_new> with a table having
2946 columns with default values that you intend to be automatically
2947 supplied by the database (e.g. an auto_increment primary key column).
2948 In normal usage, the value of such columns should NOT be included at
2949 all in the call to C<update_or_new>, even when set to C<undef>.
2951 See also L</find>, L</find_or_create> and L</find_or_new>.
2957 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2958 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2960 my $row = $self->find( $cond, $attrs );
2961 if ( defined $row ) {
2962 $row->update($cond);
2966 return $self->new_result($cond);
2973 =item Arguments: none
2975 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass> | undef
2979 Gets the contents of the cache for the resultset, if the cache is set.
2981 The cache is populated either by using the L</prefetch> attribute to
2982 L</search> or by calling L</set_cache>.
2994 =item Arguments: L<\@result_objs|DBIx::Class::Manual::ResultClass>
2996 =item Return Value: L<\@result_objs|DBIx::Class::Manual::ResultClass>
3000 Sets the contents of the cache for the resultset. Expects an arrayref
3001 of objects of the same class as those produced by the resultset. Note that
3002 if the cache is set, the resultset will return the cached objects rather
3003 than re-querying the database even if the cache attr is not set.
3005 The contents of the cache can also be populated by using the
3006 L</prefetch> attribute to L</search>.
3011 my ( $self, $data ) = @_;
3012 $self->throw_exception("set_cache requires an arrayref")
3013 if defined($data) && (ref $data ne 'ARRAY');
3014 $self->{all_cache} = $data;
3021 =item Arguments: none
3023 =item Return Value: undef
3027 Clears the cache for the resultset.
3032 shift->set_cache(undef);
3039 =item Arguments: none
3041 =item Return Value: true, if the resultset has been paginated
3049 return !!$self->{attrs}{page};
3056 =item Arguments: none
3058 =item Return Value: true, if the resultset has been ordered with C<order_by>.
3066 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
3069 =head2 related_resultset
3073 =item Arguments: $rel_name
3075 =item Return Value: L<$resultset|/search>
3079 Returns a related resultset for the supplied relationship name.
3081 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
3085 sub related_resultset {
3086 my ($self, $rel) = @_;
3088 return $self->{related_resultsets}{$rel} ||= do {
3089 my $rsrc = $self->result_source;
3090 my $rel_info = $rsrc->relationship_info($rel);
3092 $self->throw_exception(
3093 "search_related: result source '" . $rsrc->source_name .
3094 "' has no such relationship $rel")
3097 my $attrs = $self->_chain_relationship($rel);
3099 my $join_count = $attrs->{seen_join}{$rel};
3101 my $alias = $self->result_source->storage
3102 ->relname_to_table_alias($rel, $join_count);
3104 # since this is search_related, and we already slid the select window inwards
3105 # (the select/as attrs were deleted in the beginning), we need to flip all
3106 # left joins to inner, so we get the expected results
3107 # read the comment on top of the actual function to see what this does
3108 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
3111 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
3112 delete @{$attrs}{qw(result_class alias)};
3116 if (my $cache = $self->get_cache) {
3117 $related_cache = [ map
3118 { @{$_->related_resultset($rel)->get_cache||[]} }
3123 my $rel_source = $rsrc->related_source($rel);
3127 # The reason we do this now instead of passing the alias to the
3128 # search_rs below is that if you wrap/overload resultset on the
3129 # source you need to know what alias it's -going- to have for things
3130 # to work sanely (e.g. RestrictWithObject wants to be able to add
3131 # extra query restrictions, and these may need to be $alias.)
3133 my $rel_attrs = $rel_source->resultset_attributes;
3134 local $rel_attrs->{alias} = $alias;
3136 $rel_source->resultset
3140 where => $attrs->{where},
3143 $new->set_cache($related_cache) if $related_cache;
3148 =head2 current_source_alias
3152 =item Arguments: none
3154 =item Return Value: $source_alias
3158 Returns the current table alias for the result source this resultset is built
3159 on, that will be used in the SQL query. Usually it is C<me>.
3161 Currently the source alias that refers to the result set returned by a
3162 L</search>/L</find> family method depends on how you got to the resultset: it's
3163 C<me> by default, but eg. L</search_related> aliases it to the related result
3164 source name (and keeps C<me> referring to the original result set). The long
3165 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3166 (and make this method unnecessary).
3168 Thus it's currently necessary to use this method in predefined queries (see
3169 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3170 source alias of the current result set:
3172 # in a result set class
3174 my ($self, $user) = @_;
3176 my $me = $self->current_source_alias;
3178 return $self->search({
3179 "$me.modified" => $user->id,
3185 sub current_source_alias {
3186 return (shift->{attrs} || {})->{alias} || 'me';
3189 =head2 as_subselect_rs
3193 =item Arguments: none
3195 =item Return Value: L<$resultset|/search>
3199 Act as a barrier to SQL symbols. The resultset provided will be made into a
3200 "virtual view" by including it as a subquery within the from clause. From this
3201 point on, any joined tables are inaccessible to ->search on the resultset (as if
3202 it were simply where-filtered without joins). For example:
3204 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3206 # 'x' now pollutes the query namespace
3208 # So the following works as expected
3209 my $ok_rs = $rs->search({'x.other' => 1});
3211 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3212 # def) we look for one row with contradictory terms and join in another table
3213 # (aliased 'x_2') which we never use
3214 my $broken_rs = $rs->search({'x.name' => 'def'});
3216 my $rs2 = $rs->as_subselect_rs;
3218 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3219 my $not_joined_rs = $rs2->search({'x.other' => 1});
3221 # works as expected: finds a 'table' row related to two x rows (abc and def)
3222 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3224 Another example of when one might use this would be to select a subset of
3225 columns in a group by clause:
3227 my $rs = $schema->resultset('Bar')->search(undef, {
3228 group_by => [qw{ id foo_id baz_id }],
3229 })->as_subselect_rs->search(undef, {
3230 columns => [qw{ id foo_id }]
3233 In the above example normally columns would have to be equal to the group by,
3234 but because we isolated the group by into a subselect the above works.
3238 sub as_subselect_rs {
3241 my $attrs = $self->_resolved_attrs;
3243 my $fresh_rs = (ref $self)->new (
3244 $self->result_source
3247 # these pieces will be locked in the subquery
3248 delete $fresh_rs->{cond};
3249 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3251 return $fresh_rs->search( {}, {
3253 $attrs->{alias} => $self->as_query,
3254 -alias => $attrs->{alias},
3255 -rsrc => $self->result_source,
3257 alias => $attrs->{alias},
3261 # This code is called by search_related, and makes sure there
3262 # is clear separation between the joins before, during, and
3263 # after the relationship. This information is needed later
3264 # in order to properly resolve prefetch aliases (any alias
3265 # with a relation_chain_depth less than the depth of the
3266 # current prefetch is not considered)
3268 # The increments happen twice per join. An even number means a
3269 # relationship specified via a search_related, whereas an odd
3270 # number indicates a join/prefetch added via attributes
3272 # Also this code will wrap the current resultset (the one we
3273 # chain to) in a subselect IFF it contains limiting attributes
3274 sub _chain_relationship {
3275 my ($self, $rel) = @_;
3276 my $source = $self->result_source;
3277 my $attrs = { %{$self->{attrs}||{}} };
3279 # we need to take the prefetch the attrs into account before we
3280 # ->_resolve_join as otherwise they get lost - captainL
3281 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3283 delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
3285 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3288 my @force_subq_attrs = qw/offset rows group_by having/;
3291 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3293 $self->_has_resolved_attr (@force_subq_attrs)
3295 # Nuke the prefetch (if any) before the new $rs attrs
3296 # are resolved (prefetch is useless - we are wrapping
3297 # a subquery anyway).
3298 my $rs_copy = $self->search;
3299 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3300 $rs_copy->{attrs}{join},
3301 delete $rs_copy->{attrs}{prefetch},
3306 -alias => $attrs->{alias},
3307 $attrs->{alias} => $rs_copy->as_query,
3309 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3310 $seen->{-relation_chain_depth} = 0;
3312 elsif ($attrs->{from}) { #shallow copy suffices
3313 $from = [ @{$attrs->{from}} ];
3318 -alias => $attrs->{alias},
3319 $attrs->{alias} => $source->from,
3323 my $jpath = ($seen->{-relation_chain_depth})
3324 ? $from->[-1][0]{-join_path}
3327 my @requested_joins = $source->_resolve_join(
3334 push @$from, @requested_joins;
3336 $seen->{-relation_chain_depth}++;
3338 # if $self already had a join/prefetch specified on it, the requested
3339 # $rel might very well be already included. What we do in this case
3340 # is effectively a no-op (except that we bump up the chain_depth on
3341 # the join in question so we could tell it *is* the search_related)
3344 # we consider the last one thus reverse
3345 for my $j (reverse @requested_joins) {
3346 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3347 if ($rel eq $last_j) {
3348 $j->[0]{-relation_chain_depth}++;
3354 unless ($already_joined) {
3355 push @$from, $source->_resolve_join(
3363 $seen->{-relation_chain_depth}++;
3365 return {%$attrs, from => $from, seen_join => $seen};
3368 sub _resolved_attrs {
3370 return $self->{_attrs} if $self->{_attrs};
3372 my $attrs = { %{ $self->{attrs} || {} } };
3373 my $source = $self->result_source;
3374 my $alias = $attrs->{alias};
3376 # default selection list
3377 $attrs->{columns} = [ $source->columns ]
3378 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
3380 # merge selectors together
3381 for (qw/columns select as/) {
3382 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, delete $attrs->{"+$_"})
3383 if $attrs->{$_} or $attrs->{"+$_"};
3386 # disassemble columns
3388 if (my $cols = delete $attrs->{columns}) {
3389 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3390 if (ref $c eq 'HASH') {
3391 for my $as (sort keys %$c) {
3392 push @sel, $c->{$as};
3403 # when trying to weed off duplicates later do not go past this point -
3404 # everything added from here on is unbalanced "anyone's guess" stuff
3405 my $dedup_stop_idx = $#as;
3407 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3409 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3410 if $attrs->{select};
3412 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3413 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel;
3415 # disqualify all $alias.col as-bits (inflate-map mandated)
3416 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as;
3418 # de-duplicate the result (remove *identical* select/as pairs)
3419 # and also die on duplicate {as} pointing to different {select}s
3420 # not using a c-style for as the condition is prone to shrinkage
3423 while ($i <= $dedup_stop_idx) {
3424 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3429 elsif ($seen->{$as[$i]}++) {
3430 $self->throw_exception(
3431 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3439 $attrs->{select} = \@sel;
3440 $attrs->{as} = \@as;
3442 $attrs->{from} ||= [{
3444 -alias => $self->{attrs}{alias},
3445 $self->{attrs}{alias} => $source->from,
3448 if ( $attrs->{join} || $attrs->{prefetch} ) {
3450 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3451 if ref $attrs->{from} ne 'ARRAY';
3453 my $join = (delete $attrs->{join}) || {};
3455 if ( defined $attrs->{prefetch} ) {
3456 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3459 $attrs->{from} = # have to copy here to avoid corrupting the original
3461 @{ $attrs->{from} },
3462 $source->_resolve_join(
3465 { %{ $attrs->{seen_join} || {} } },
3466 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3467 ? $attrs->{from}[-1][0]{-join_path}
3474 if ( defined $attrs->{order_by} ) {
3475 $attrs->{order_by} = (
3476 ref( $attrs->{order_by} ) eq 'ARRAY'
3477 ? [ @{ $attrs->{order_by} } ]
3478 : [ $attrs->{order_by} || () ]
3482 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3483 $attrs->{group_by} = [ $attrs->{group_by} ];
3486 # generate the distinct induced group_by early, as prefetch will be carried via a
3487 # subquery (since a group_by is present)
3488 if (delete $attrs->{distinct}) {
3489 if ($attrs->{group_by}) {
3490 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3493 $attrs->{_grouped_by_distinct} = 1;
3494 # distinct affects only the main selection part, not what prefetch may
3496 $attrs->{group_by} = $source->storage->_group_over_selection (
3504 # generate selections based on the prefetch helper
3506 $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
3507 if defined $attrs->{prefetch};
3511 $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
3512 if $attrs->{_dark_selector};
3514 $attrs->{collapse} = 1;
3516 # this is a separate structure (we don't look in {from} directly)
3517 # as the resolver needs to shift things off the lists to work
3518 # properly (identical-prefetches on different branches)
3520 if (ref $attrs->{from} eq 'ARRAY') {
3522 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3524 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3525 next unless $j->[0]{-alias};
3526 next unless $j->[0]{-join_path};
3527 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3529 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3532 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3533 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3537 my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
3539 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3540 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3543 if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
3544 $attrs->{_related_results_construction} = 1;
3547 $attrs->{collapse} = 0;
3550 # run through the resulting joinstructure (starting from our current slot)
3551 # and unset collapse if proven unnesessary
3553 # also while we are at it find out if the current root source has
3554 # been premultiplied by previous related_source chaining
3556 # this allows to predict whether a root object with all other relation
3557 # data set to NULL is in fact unique
3558 if ($attrs->{collapse}) {
3560 if (ref $attrs->{from} eq 'ARRAY') {
3562 if (@{$attrs->{from}} <= 1) {
3563 # no joins - no collapse
3564 $attrs->{collapse} = 0;
3567 # find where our table-spec starts
3568 my @fromlist = @{$attrs->{from}};
3570 my $t = shift @fromlist;
3573 # me vs join from-spec distinction - a ref means non-root
3574 if (ref $t eq 'ARRAY') {
3576 $is_multi ||= ! $t->{-is_single};
3578 last if ($t->{-alias} && $t->{-alias} eq $alias);
3579 $attrs->{_main_source_premultiplied} ||= $is_multi;
3582 # no non-singles remaining, nor any premultiplication - nothing to collapse
3584 ! $attrs->{_main_source_premultiplied}
3586 ! List::Util::first { ! $_->[0]{-is_single} } @fromlist
3588 $attrs->{collapse} = 0;
3594 # if we can not analyze the from - err on the side of safety
3595 $attrs->{_main_source_premultiplied} = 1;
3599 # if both page and offset are specified, produce a combined offset
3600 # even though it doesn't make much sense, this is what pre 081xx has
3602 if (my $page = delete $attrs->{page}) {
3604 ($attrs->{rows} * ($page - 1))
3606 ($attrs->{offset} || 0)
3610 return $self->{_attrs} = $attrs;
3614 my ($self, $attr) = @_;
3616 if (ref $attr eq 'HASH') {
3617 return $self->_rollout_hash($attr);
3618 } elsif (ref $attr eq 'ARRAY') {
3619 return $self->_rollout_array($attr);
3625 sub _rollout_array {
3626 my ($self, $attr) = @_;
3629 foreach my $element (@{$attr}) {
3630 if (ref $element eq 'HASH') {
3631 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3632 } elsif (ref $element eq 'ARRAY') {
3633 # XXX - should probably recurse here
3634 push( @rolled_array, @{$self->_rollout_array($element)} );
3636 push( @rolled_array, $element );
3639 return \@rolled_array;
3643 my ($self, $attr) = @_;
3646 foreach my $key (keys %{$attr}) {
3647 push( @rolled_array, { $key => $attr->{$key} } );
3649 return \@rolled_array;
3652 sub _calculate_score {
3653 my ($self, $a, $b) = @_;
3655 if (defined $a xor defined $b) {
3658 elsif (not defined $a) {
3662 if (ref $b eq 'HASH') {
3663 my ($b_key) = keys %{$b};
3664 if (ref $a eq 'HASH') {
3665 my ($a_key) = keys %{$a};
3666 if ($a_key eq $b_key) {
3667 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3672 return ($a eq $b_key) ? 1 : 0;
3675 if (ref $a eq 'HASH') {
3676 my ($a_key) = keys %{$a};
3677 return ($b eq $a_key) ? 1 : 0;
3679 return ($b eq $a) ? 1 : 0;
3684 sub _merge_joinpref_attr {
3685 my ($self, $orig, $import) = @_;
3687 return $import unless defined($orig);
3688 return $orig unless defined($import);
3690 $orig = $self->_rollout_attr($orig);
3691 $import = $self->_rollout_attr($import);
3694 foreach my $import_element ( @{$import} ) {
3695 # find best candidate from $orig to merge $b_element into
3696 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3697 foreach my $orig_element ( @{$orig} ) {
3698 my $score = $self->_calculate_score( $orig_element, $import_element );
3699 if ($score > $best_candidate->{score}) {
3700 $best_candidate->{position} = $position;
3701 $best_candidate->{score} = $score;
3705 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3706 $import_key = '' if not defined $import_key;
3708 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3709 push( @{$orig}, $import_element );
3711 my $orig_best = $orig->[$best_candidate->{position}];
3712 # merge orig_best and b_element together and replace original with merged
3713 if (ref $orig_best ne 'HASH') {
3714 $orig->[$best_candidate->{position}] = $import_element;
3715 } elsif (ref $import_element eq 'HASH') {
3716 my ($key) = keys %{$orig_best};
3717 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3720 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3723 return @$orig ? $orig : ();
3731 require Hash::Merge;
3732 my $hm = Hash::Merge->new;
3734 $hm->specify_behavior({
3737 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3739 if ($defl xor $defr) {
3740 return [ $defl ? $_[0] : $_[1] ];
3745 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3749 return [$_[0], $_[1]];
3753 return $_[1] if !defined $_[0];
3754 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3755 return [$_[0], @{$_[1]}]
3758 return [] if !defined $_[0] and !keys %{$_[1]};
3759 return [ $_[1] ] if !defined $_[0];
3760 return [ $_[0] ] if !keys %{$_[1]};
3761 return [$_[0], $_[1]]
3766 return $_[0] if !defined $_[1];
3767 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3768 return [@{$_[0]}, $_[1]]
3771 my @ret = @{$_[0]} or return $_[1];
3772 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3773 my %idx = map { $_ => 1 } @ret;
3774 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3778 return [ $_[1] ] if ! @{$_[0]};
3779 return $_[0] if !keys %{$_[1]};
3780 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3781 return [ @{$_[0]}, $_[1] ];
3786 return [] if !keys %{$_[0]} and !defined $_[1];
3787 return [ $_[0] ] if !defined $_[1];
3788 return [ $_[1] ] if !keys %{$_[0]};
3789 return [$_[0], $_[1]]
3792 return [] if !keys %{$_[0]} and !@{$_[1]};
3793 return [ $_[0] ] if !@{$_[1]};
3794 return $_[1] if !keys %{$_[0]};
3795 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3796 return [ $_[0], @{$_[1]} ];
3799 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3800 return [ $_[0] ] if !keys %{$_[1]};
3801 return [ $_[1] ] if !keys %{$_[0]};
3802 return [ $_[0] ] if $_[0] eq $_[1];
3803 return [ $_[0], $_[1] ];
3806 } => 'DBIC_RS_ATTR_MERGER');
3810 return $hm->merge ($_[1], $_[2]);
3814 sub STORABLE_freeze {
3815 my ($self, $cloning) = @_;
3816 my $to_serialize = { %$self };
3818 # A cursor in progress can't be serialized (and would make little sense anyway)
3819 # the parser can be regenerated (and can't be serialized)
3820 delete @{$to_serialize}{qw/cursor _row_parser _result_inflator/};
3822 # nor is it sensical to store a not-yet-fired-count pager
3823 if ($to_serialize->{pager} and ref $to_serialize->{pager}{total_entries} eq 'CODE') {
3824 delete $to_serialize->{pager};
3827 Storable::nfreeze($to_serialize);
3830 # need this hook for symmetry
3832 my ($self, $cloning, $serialized) = @_;
3834 %$self = %{ Storable::thaw($serialized) };
3840 =head2 throw_exception
3842 See L<DBIx::Class::Schema/throw_exception> for details.
3846 sub throw_exception {
3849 if (ref $self and my $rsrc = $self->result_source) {
3850 $rsrc->throw_exception(@_)
3853 DBIx::Class::Exception->throw(@_);
3861 # XXX: FIXME: Attributes docs need clearing up
3865 Attributes are used to refine a ResultSet in various ways when
3866 searching for data. They can be passed to any method which takes an
3867 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3870 Default attributes can be set on the result class using
3871 L<DBIx::Class::ResultSource/resultset_attributes>. (Please read
3872 the CAVEATS on that feature before using it!)
3874 These are in no particular order:
3880 =item Value: ( $order_by | \@order_by | \%order_by )
3884 Which column(s) to order the results by.
3886 [The full list of suitable values is documented in
3887 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3890 If a single column name, or an arrayref of names is supplied, the
3891 argument is passed through directly to SQL. The hashref syntax allows
3892 for connection-agnostic specification of ordering direction:
3894 For descending order:
3896 order_by => { -desc => [qw/col1 col2 col3/] }
3898 For explicit ascending order:
3900 order_by => { -asc => 'col' }
3902 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3903 supported, although you are strongly encouraged to use the hashref
3904 syntax as outlined above.
3910 =item Value: \@columns | \%columns | $column
3914 Shortcut to request a particular set of columns to be retrieved. Each
3915 column spec may be a string (a table column name), or a hash (in which
3916 case the key is the C<as> value, and the value is used as the C<select>
3917 expression). Adds C<me.> onto the start of any column without a C<.> in
3918 it and sets C<select> from that, then auto-populates C<as> from
3919 C<select> as normal. (You may also use the C<cols> attribute, as in
3920 earlier versions of DBIC, but this is deprecated.)
3922 Essentially C<columns> does the same as L</select> and L</as>.
3924 columns => [ 'foo', { bar => 'baz' } ]
3928 select => [qw/foo baz/],
3935 =item Value: \@columns
3939 Indicates additional columns to be selected from storage. Works the same as
3940 L</columns> but adds columns to the selection. (You may also use the
3941 C<include_columns> attribute, as in earlier versions of DBIC, but this is
3942 deprecated). For example:-
3944 $schema->resultset('CD')->search(undef, {
3945 '+columns' => ['artist.name'],
3949 would return all CDs and include a 'name' column to the information
3950 passed to object inflation. Note that the 'artist' is the name of the
3951 column (or relationship) accessor, and 'name' is the name of the column
3952 accessor in the related table.
3954 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3955 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3956 unary plus operator before it.
3958 =head2 include_columns
3962 =item Value: \@columns
3966 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3972 =item Value: \@select_columns
3976 Indicates which columns should be selected from the storage. You can use
3977 column names, or in the case of RDBMS back ends, function or stored procedure
3980 $rs = $schema->resultset('Employee')->search(undef, {
3983 { count => 'employeeid' },
3984 { max => { length => 'name' }, -as => 'longest_name' }
3989 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3991 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3992 use L</select>, to instruct DBIx::Class how to store the result of the column.
3993 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3994 identifier aliasing. You can however alias a function, so you can use it in
3995 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3996 attribute> supplied as shown in the example above.
3998 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3999 Not doing so causes Perl to incorrectly interpret them as a bareword with a
4000 unary plus operator before it.
4006 Indicates additional columns to be selected from storage. Works the same as
4007 L</select> but adds columns to the default selection, instead of specifying
4016 =item Value: \@inflation_names
4020 Indicates column names for object inflation. That is L</as> indicates the
4021 slot name in which the column value will be stored within the
4022 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
4023 identifier by the C<get_column> method (or via the object accessor B<if one
4024 with the same name already exists>) as shown below. The L</as> attribute has
4025 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
4027 $rs = $schema->resultset('Employee')->search(undef, {
4030 { count => 'employeeid' },
4031 { max => { length => 'name' }, -as => 'longest_name' }
4040 If the object against which the search is performed already has an accessor
4041 matching a column name specified in C<as>, the value can be retrieved using
4042 the accessor as normal:
4044 my $name = $employee->name();
4046 If on the other hand an accessor does not exist in the object, you need to
4047 use C<get_column> instead:
4049 my $employee_count = $employee->get_column('employee_count');
4051 You can create your own accessors if required - see
4052 L<DBIx::Class::Manual::Cookbook> for details.
4058 Indicates additional column names for those added via L</+select>. See L</as>.
4066 =item Value: ($rel_name | \@rel_names | \%rel_names)
4070 Contains a list of relationships that should be joined for this query. For
4073 # Get CDs by Nine Inch Nails
4074 my $rs = $schema->resultset('CD')->search(
4075 { 'artist.name' => 'Nine Inch Nails' },
4076 { join => 'artist' }
4079 Can also contain a hash reference to refer to the other relation's relations.
4082 package MyApp::Schema::Track;
4083 use base qw/DBIx::Class/;
4084 __PACKAGE__->table('track');
4085 __PACKAGE__->add_columns(qw/trackid cd position title/);
4086 __PACKAGE__->set_primary_key('trackid');
4087 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
4090 # In your application
4091 my $rs = $schema->resultset('Artist')->search(
4092 { 'track.title' => 'Teardrop' },
4094 join => { cd => 'track' },
4095 order_by => 'artist.name',
4099 You need to use the relationship (not the table) name in conditions,
4100 because they are aliased as such. The current table is aliased as "me", so
4101 you need to use me.column_name in order to avoid ambiguity. For example:
4103 # Get CDs from 1984 with a 'Foo' track
4104 my $rs = $schema->resultset('CD')->search(
4107 'tracks.name' => 'Foo'
4109 { join => 'tracks' }
4112 If the same join is supplied twice, it will be aliased to <rel>_2 (and
4113 similarly for a third time). For e.g.
4115 my $rs = $schema->resultset('Artist')->search({
4116 'cds.title' => 'Down to Earth',
4117 'cds_2.title' => 'Popular',
4119 join => [ qw/cds cds/ ],
4122 will return a set of all artists that have both a cd with title 'Down
4123 to Earth' and a cd with title 'Popular'.
4125 If you want to fetch related objects from other tables as well, see L</prefetch>
4128 NOTE: An internal join-chain pruner will discard certain joins while
4129 constructing the actual SQL query, as long as the joins in question do not
4130 affect the retrieved result. This for example includes 1:1 left joins
4131 that are not part of the restriction specification (WHERE/HAVING) nor are
4132 a part of the query selection.
4134 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
4140 =item Value: (0 | 1)
4144 When set to a true value, indicates that any rows fetched from joined has_many
4145 relationships are to be aggregated into the corresponding "parent" object. For
4146 example, the resultset:
4148 my $rs = $schema->resultset('CD')->search({}, {
4149 '+columns' => [ qw/ tracks.title tracks.position / ],
4154 While executing the following query:
4156 SELECT me.*, tracks.title, tracks.position
4158 LEFT JOIN track tracks
4159 ON tracks.cdid = me.cdid
4161 Will return only as many objects as there are rows in the CD source, even
4162 though the result of the query may span many rows. Each of these CD objects
4163 will in turn have multiple "Track" objects hidden behind the has_many
4164 generated accessor C<tracks>. Without C<< collapse => 1 >>, the return values
4165 of this resultset would be as many CD objects as there are tracks (a "Cartesian
4166 product"), with each CD object containing exactly one of all fetched Track data.
4168 When a collapse is requested on a non-ordered resultset, an order by some
4169 unique part of the main source (the left-most table) is inserted automatically.
4170 This is done so that the resultset is allowed to be "lazy" - calling
4171 L<< $rs->next|/next >> will fetch only as many rows as it needs to build the next
4172 object with all of its related data.
4174 If an L</order_by> is already declared, and orders the resultset in a way that
4175 makes collapsing as described above impossible (e.g. C<< ORDER BY
4176 has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
4177 switch to "eager" mode and slurp the entire resultset before consturcting the
4178 first object returned by L</next>.
4180 Setting this attribute on a resultset that does not join any has_many
4181 relations is a no-op.
4183 For a more in-depth discussion, see L</PREFETCHING>.
4189 =item Value: ($rel_name | \@rel_names | \%rel_names)
4193 This attribute is a shorthand for specifying a L</join> spec, adding all
4194 columns from the joined related sources as L</+columns> and setting
4195 L</collapse> to a true value. For example, the following two queries are
4198 my $rs = $schema->resultset('Artist')->search({}, {
4199 prefetch => { cds => ['genre', 'tracks' ] },
4204 my $rs = $schema->resultset('Artist')->search({}, {
4205 join => { cds => ['genre', 'tracks' ] },
4209 { +{ "cds.$_" => "cds.$_" } }
4210 $schema->source('Artist')->related_source('cds')->columns
4213 { +{ "cds.genre.$_" => "genre.$_" } }
4214 $schema->source('Artist')->related_source('cds')->related_source('genre')->columns
4217 { +{ "cds.tracks.$_" => "tracks.$_" } }
4218 $schema->source('Artist')->related_source('cds')->related_source('tracks')->columns
4223 Both producing the following SQL:
4225 SELECT me.artistid, me.name, me.rank, me.charfield,
4226 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track,
4227 genre.genreid, genre.name,
4228 tracks.trackid, tracks.cd, tracks.position, tracks.title, tracks.last_updated_on, tracks.last_updated_at
4231 ON cds.artist = me.artistid
4232 LEFT JOIN genre genre
4233 ON genre.genreid = cds.genreid
4234 LEFT JOIN track tracks
4235 ON tracks.cd = cds.cdid
4236 ORDER BY me.artistid
4238 While L</prefetch> implies a L</join>, it is ok to mix the two together, as
4239 the arguments are properly merged and generally do the right thing. For
4240 example, you may want to do the following:
4242 my $artists_and_cds_without_genre = $schema->resultset('Artist')->search(
4243 { 'genre.genreid' => undef },
4245 join => { cds => 'genre' },
4250 Which generates the following SQL:
4252 SELECT me.artistid, me.name, me.rank, me.charfield,
4253 cds.cdid, cds.artist, cds.title, cds.year, cds.genreid, cds.single_track
4256 ON cds.artist = me.artistid
4257 LEFT JOIN genre genre
4258 ON genre.genreid = cds.genreid
4259 WHERE genre.genreid IS NULL
4260 ORDER BY me.artistid
4262 For a more in-depth discussion, see L</PREFETCHING>.
4268 =item Value: $source_alias
4272 Sets the source alias for the query. Normally, this defaults to C<me>, but
4273 nested search queries (sub-SELECTs) might need specific aliases set to
4274 reference inner queries. For example:
4277 ->related_resultset('CDs')
4278 ->related_resultset('Tracks')
4280 'track.id' => { -ident => 'none_search.id' },
4284 my $ids = $self->search({
4287 alias => 'none_search',
4288 group_by => 'none_search.id',
4289 })->get_column('id')->as_query;
4291 $self->search({ id => { -in => $ids } })
4293 This attribute is directly tied to L</current_source_alias>.
4303 Makes the resultset paged and specifies the page to retrieve. Effectively
4304 identical to creating a non-pages resultset and then calling ->page($page)
4307 If L</rows> attribute is not specified it defaults to 10 rows per page.
4309 When you have a paged resultset, L</count> will only return the number
4310 of rows in the page. To get the total, use the L</pager> and call
4311 C<total_entries> on it.
4321 Specifies the maximum number of rows for direct retrieval or the number of
4322 rows per page if the page attribute or method is used.
4328 =item Value: $offset
4332 Specifies the (zero-based) row number for the first row to be returned, or the
4333 of the first row of the first page if paging is used.
4335 =head2 software_limit
4339 =item Value: (0 | 1)
4343 When combined with L</rows> and/or L</offset> the generated SQL will not
4344 include any limit dialect stanzas. Instead the entire result will be selected
4345 as if no limits were specified, and DBIC will perform the limit locally, by
4346 artificially advancing and finishing the resulting L</cursor>.
4348 This is the recommended way of performing resultset limiting when no sane RDBMS
4349 implementation is available (e.g.
4350 L<Sybase ASE|DBIx::Class::Storage::DBI::Sybase::ASE> using the
4351 L<Generic Sub Query|DBIx::Class::SQLMaker::LimitDialects/GenericSubQ> hack)
4357 =item Value: \@columns
4361 A arrayref of columns to group by. Can include columns of joined tables.
4363 group_by => [qw/ column1 column2 ... /]
4369 =item Value: $condition
4373 HAVING is a select statement attribute that is applied between GROUP BY and
4374 ORDER BY. It is applied to the after the grouping calculations have been
4377 having => { 'count_employee' => { '>=', 100 } }
4379 or with an in-place function in which case literal SQL is required:
4381 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4387 =item Value: (0 | 1)
4391 Set to 1 to group by all columns. If the resultset already has a group_by
4392 attribute, this setting is ignored and an appropriate warning is issued.
4398 Adds to the WHERE clause.
4400 # only return rows WHERE deleted IS NULL for all searches
4401 __PACKAGE__->resultset_attributes({ where => { deleted => undef } });
4403 Can be overridden by passing C<< { where => undef } >> as an attribute
4406 For more complicated where clauses see L<SQL::Abstract/WHERE CLAUSES>.
4412 Set to 1 to cache search results. This prevents extra SQL queries if you
4413 revisit rows in your ResultSet:
4415 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4417 while( my $artist = $resultset->next ) {
4421 $rs->first; # without cache, this would issue a query
4423 By default, searches are not cached.
4425 For more examples of using these attributes, see
4426 L<DBIx::Class::Manual::Cookbook>.
4432 =item Value: ( 'update' | 'shared' | \$scalar )
4436 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
4437 ... FOR SHARED. If \$scalar is passed, this is taken directly and embedded in the
4442 DBIx::Class supports arbitrary related data prefetching from multiple related
4443 sources. Any combination of relationship types and column sets are supported.
4444 If L<collapsing|/collapse> is requested, there is an additional requirement of
4445 selecting enough data to make every individual object uniquely identifiable.
4447 Here are some more involved examples, based on the following relationship map:
4450 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
4451 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
4452 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
4454 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
4456 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
4460 my $rs = $schema->resultset('Tag')->search(
4469 The initial search results in SQL like the following:
4471 SELECT tag.*, cd.*, artist.* FROM tag
4472 JOIN cd ON tag.cd = cd.cdid
4473 JOIN artist ON cd.artist = artist.artistid
4475 L<DBIx::Class> has no need to go back to the database when we access the
4476 C<cd> or C<artist> relationships, which saves us two SQL statements in this
4479 Simple prefetches will be joined automatically, so there is no need
4480 for a C<join> attribute in the above search.
4482 The L</prefetch> attribute can be used with any of the relationship types
4483 and multiple prefetches can be specified together. Below is a more complex
4484 example that prefetches a CD's artist, its liner notes (if present),
4485 the cover image, the tracks on that CD, and the guests on those
4488 my $rs = $schema->resultset('CD')->search(
4492 { artist => 'record_label'}, # belongs_to => belongs_to
4493 'liner_note', # might_have
4494 'cover_image', # has_one
4495 { tracks => 'guests' }, # has_many => has_many
4500 This will produce SQL like the following:
4502 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4506 ON artist.artistid = me.artistid
4507 JOIN record_label record_label
4508 ON record_label.labelid = artist.labelid
4509 LEFT JOIN track tracks
4510 ON tracks.cdid = me.cdid
4511 LEFT JOIN guest guests
4512 ON guests.trackid = track.trackid
4513 LEFT JOIN liner_notes liner_note
4514 ON liner_note.cdid = me.cdid
4515 JOIN cd_artwork cover_image
4516 ON cover_image.cdid = me.cdid
4519 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4520 C<tracks>, and C<guests> of the CD will all be available through the
4521 relationship accessors without the need for additional queries to the
4526 Prefetch does a lot of deep magic. As such, it may not behave exactly
4527 as you might expect.
4533 Prefetch uses the L</cache> to populate the prefetched relationships. This
4534 may or may not be what you want.
4538 If you specify a condition on a prefetched relationship, ONLY those
4539 rows that match the prefetched condition will be fetched into that relationship.
4540 This means that adding prefetch to a search() B<may alter> what is returned by
4541 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4543 my $artist_rs = $schema->resultset('Artist')->search({
4549 my $count = $artist_rs->first->cds->count;
4551 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4553 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4555 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4557 That cmp_ok() may or may not pass depending on the datasets involved. In other
4558 words the C<WHERE> condition would apply to the entire dataset, just like
4559 it would in regular SQL. If you want to add a condition only to the "right side"
4560 of a C<LEFT JOIN> - consider declaring and using a L<relationship with a custom
4561 condition|DBIx::Class::Relationship::Base/condition>
4565 =head1 DBIC BIND VALUES
4567 Because DBIC may need more information to bind values than just the column name
4568 and value itself, it uses a special format for both passing and receiving bind
4569 values. Each bind value should be composed of an arrayref of
4570 C<< [ \%args => $val ] >>. The format of C<< \%args >> is currently:
4576 If present (in any form), this is what is being passed directly to bind_param.
4577 Note that different DBD's expect different bind args. (e.g. DBD::SQLite takes
4578 a single numerical type, while DBD::Pg takes a hashref if bind options.)
4580 If this is specified, all other bind options described below are ignored.
4584 If present, this is used to infer the actual bind attribute by passing to
4585 C<< $resolved_storage->bind_attribute_by_data_type() >>. Defaults to the
4586 "data_type" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>.
4588 Note that the data type is somewhat freeform (hence the sqlt_ prefix);
4589 currently drivers are expected to "Do the Right Thing" when given a common
4590 datatype name. (Not ideal, but that's what we got at this point.)
4594 Currently used to correctly allocate buffers for bind_param_inout().
4595 Defaults to "size" from the L<add_columns column info|DBIx::Class::ResultSource/add_columns>,
4596 or to a sensible value based on the "data_type".
4600 Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
4601 explicitly specified they are never overriden). Also used by some weird DBDs,
4602 where the column name should be available at bind_param time (e.g. Oracle).
4606 For backwards compatibility and convenience, the following shortcuts are
4609 [ $name => $val ] === [ { dbic_colname => $name }, $val ]
4610 [ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
4611 [ undef, $val ] === [ {}, $val ]
4613 =head1 AUTHOR AND CONTRIBUTORS
4615 See L<AUTHOR|DBIx::Class/AUTHOR> and L<CONTRIBUTORS|DBIx::Class/CONTRIBUTORS> in DBIx::Class
4619 You may distribute this code under the same terms as Perl itself.