1 package DBIx::Class::ResultSet;
5 use base qw/DBIx::Class/;
7 use DBIx::Class::Exception;
8 use DBIx::Class::ResultSetColumn;
9 use Scalar::Util qw/blessed weaken/;
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 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class result_source/);
32 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
36 my $users_rs = $schema->resultset('User');
37 while( $user = $users_rs->next) {
38 print $user->username;
41 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
42 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
46 A ResultSet is an object which stores a set of conditions representing
47 a query. It is the backbone of DBIx::Class (i.e. the really
48 important/useful bit).
50 No SQL is executed on the database when a ResultSet is created, it
51 just stores all the conditions needed to create the query.
53 A basic ResultSet representing the data of an entire table is returned
54 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
55 L<Source|DBIx::Class::Manual::Glossary/Source> name.
57 my $users_rs = $schema->resultset('User');
59 A new ResultSet is returned from calling L</search> on an existing
60 ResultSet. The new one will contain all the conditions of the
61 original, plus any new conditions added in the C<search> call.
63 A ResultSet also incorporates an implicit iterator. L</next> and L</reset>
64 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
67 The query that the ResultSet represents is B<only> executed against
68 the database when these methods are called:
69 L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
71 If a resultset is used in a numeric context it returns the L</count>.
72 However, if it is used in a boolean context it is B<always> true. So if
73 you want to check if a resultset has any results, you must use C<if $rs
78 =head2 Chaining resultsets
80 Let's say you've got a query that needs to be run to return some data
81 to the user. But, you have an authorization system in place that
82 prevents certain users from seeing certain information. So, you want
83 to construct the basic query in one method, but add constraints to it in
88 my $request = $self->get_request; # Get a request object somehow.
89 my $schema = $self->get_schema; # Get the DBIC schema object somehow.
91 my $cd_rs = $schema->resultset('CD')->search({
92 title => $request->param('title'),
93 year => $request->param('year'),
96 $cd_rs = $self->apply_security_policy( $cd_rs );
101 sub apply_security_policy {
110 =head3 Resolving conditions and attributes
112 When a resultset is chained from another resultset, conditions and
113 attributes with the same keys need resolving.
115 L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
116 into the existing ones from the original resultset.
118 The L</where> and L</having> attributes, and any search conditions, are
119 merged with an SQL C<AND> to the existing condition from the original
122 All other attributes are overridden by any new ones supplied in the
125 =head2 Multiple queries
127 Since a resultset just defines a query, you can do all sorts of
128 things with it with the same object.
130 # Don't hit the DB yet.
131 my $cd_rs = $schema->resultset('CD')->search({
132 title => 'something',
136 # Each of these hits the DB individually.
137 my $count = $cd_rs->count;
138 my $most_recent = $cd_rs->get_column('date_released')->max();
139 my @records = $cd_rs->all;
141 And it's not just limited to SELECT statements.
147 $cd_rs->create({ artist => 'Fred' });
149 Which is the same as:
151 $schema->resultset('CD')->create({
152 title => 'something',
157 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
165 =item Arguments: $source, \%$attrs
167 =item Return Value: $rs
171 The resultset constructor. Takes a source object (usually a
172 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
173 L</ATTRIBUTES> below). Does not perform any queries -- these are
174 executed as needed by the other methods.
176 Generally you won't need to construct a resultset manually. You'll
177 automatically get one from e.g. a L</search> called in scalar context:
179 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
181 IMPORTANT: If called on an object, proxies to new_result instead so
183 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
185 will return a CD object, not a ResultSet.
191 return $class->new_result(@_) if ref $class;
193 my ($source, $attrs) = @_;
194 $source = $source->resolve
195 if $source->isa('DBIx::Class::ResultSourceHandle');
196 $attrs = { %{$attrs||{}} };
198 if ($attrs->{page}) {
199 $attrs->{rows} ||= 10;
202 $attrs->{alias} ||= 'me';
205 result_source => $source,
206 cond => $attrs->{where},
212 $attrs->{result_class} || $source->result_class
222 =item Arguments: $cond, \%attrs?
224 =item Return Value: $resultset (scalar context) || @row_objs (list context)
228 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
229 my $new_rs = $cd_rs->search({ year => 2005 });
231 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
232 # year = 2005 OR year = 2004
234 In list context, C<< ->all() >> is called implicitly on the resultset, thus
235 returning a list of row objects instead. To avoid that, use L</search_rs>.
237 If you need to pass in additional attributes but no additional condition,
238 call it as C<search(undef, \%attrs)>.
240 # "SELECT name, artistid FROM $artist_table"
241 my @all_artists = $schema->resultset('Artist')->search(undef, {
242 columns => [qw/name artistid/],
245 For a list of attributes that can be passed to C<search>, see
246 L</ATTRIBUTES>. For more examples of using this function, see
247 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
248 documentation for the first argument, see L<SQL::Abstract>.
250 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
254 Note that L</search> does not process/deflate any of the values passed in the
255 L<SQL::Abstract>-compatible search condition structure. This is unlike other
256 condition-bound methods L</new>, L</create> and L</find>. The user must ensure
257 manually that any value passed to this method will stringify to something the
258 RDBMS knows how to deal with. A notable example is the handling of L<DateTime>
259 objects, for more info see:
260 L<DBIx::Class::Manual::Cookbook/Formatting_DateTime_objects_in_queries>.
266 my $rs = $self->search_rs( @_ );
271 elsif (defined wantarray) {
275 # we can be called by a relationship helper, which in
276 # turn may be called in void context due to some braindead
277 # overload or whatever else the user decided to be clever
278 # at this particular day. Thus limit the exception to
279 # external code calls only
280 $self->throw_exception ('->search is *not* a mutator, calling it in void context makes no sense')
281 if (caller)[0] !~ /^\QDBIx::Class::/;
291 =item Arguments: $cond, \%attrs?
293 =item Return Value: $resultset
297 This method does the same exact thing as search() except it will
298 always return a resultset, even in list context.
305 # Special-case handling for (undef, undef).
306 if ( @_ == 2 && !defined $_[1] && !defined $_[0] ) {
312 if (ref $_[-1] eq 'HASH') {
313 # copy for _normalize_selection
314 $call_attrs = { %{ pop @_ } };
316 elsif (! defined $_[-1] ) {
317 pop @_; # search({}, undef)
321 # see if we can keep the cache (no $rs changes)
323 my %safe = (alias => 1, cache => 1);
324 if ( ! List::Util::first { !$safe{$_} } keys %$call_attrs and (
327 ref $_[0] eq 'HASH' && ! keys %{$_[0]}
329 ref $_[0] eq 'ARRAY' && ! @{$_[0]}
331 $cache = $self->get_cache;
334 my $rsrc = $self->result_source;
336 my $old_attrs = { %{$self->{attrs}} };
337 my $old_having = delete $old_attrs->{having};
338 my $old_where = delete $old_attrs->{where};
340 my $new_attrs = { %$old_attrs };
342 # take care of call attrs (only if anything is changing)
343 if (keys %$call_attrs) {
345 $self->throw_exception ('_trailing_select is not a public attribute - do not use it in search()')
346 if ( exists $call_attrs->{_trailing_select} or exists $call_attrs->{'+_trailing_select'} );
348 my @selector_attrs = qw/select as columns cols +select +as +columns include_columns _trailing_select +_trailing_select/;
350 # Normalize the selector list (operates on the passed-in attr structure)
351 # Need to do it on every chain instead of only once on _resolved_attrs, in
352 # order to separate 'as'-ed from blind 'select's
353 $self->_normalize_selection ($call_attrs);
355 # start with blind overwriting merge, exclude selector attrs
356 $new_attrs = { %{$old_attrs}, %{$call_attrs} };
357 delete @{$new_attrs}{@selector_attrs};
359 # reset the current selector list if new selectors are supplied
360 if (List::Util::first { exists $call_attrs->{$_} } qw/columns cols select as/) {
361 delete @{$old_attrs}{@selector_attrs};
364 for (@selector_attrs) {
365 $new_attrs->{$_} = $self->_merge_attr($old_attrs->{$_}, $call_attrs->{$_})
366 if ( exists $old_attrs->{$_} or exists $call_attrs->{$_} );
369 # older deprecated name, use only if {columns} is not there
370 if (my $c = delete $new_attrs->{cols}) {
371 if ($new_attrs->{columns}) {
372 carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
375 $new_attrs->{columns} = $c;
380 # join/prefetch use their own crazy merging heuristics
381 foreach my $key (qw/join prefetch/) {
382 $new_attrs->{$key} = $self->_merge_joinpref_attr($old_attrs->{$key}, $call_attrs->{$key})
383 if exists $call_attrs->{$key};
386 # stack binds together
387 $new_attrs->{bind} = [ @{ $old_attrs->{bind} || [] }, @{ $call_attrs->{bind} || [] } ];
391 # rip apart the rest of @_, parse a condition
394 if (ref $_[0] eq 'HASH') {
395 (keys %{$_[0]}) ? $_[0] : undef
401 $self->throw_exception('Odd number of arguments to search')
409 if( @_ > 1 and ! $rsrc->result_class->isa('DBIx::Class::CDBICompat') ) {
410 carp_unique 'search( %condition ) is deprecated, use search( \%condition ) instead';
413 for ($old_where, $call_cond) {
415 $new_attrs->{where} = $self->_stack_cond (
416 $_, $new_attrs->{where}
421 if (defined $old_having) {
422 $new_attrs->{having} = $self->_stack_cond (
423 $old_having, $new_attrs->{having}
427 my $rs = (ref $self)->new($rsrc, $new_attrs);
429 $rs->set_cache($cache) if ($cache);
434 sub _normalize_selection {
435 my ($self, $attrs) = @_;
438 $attrs->{'+columns'} = $self->_merge_attr($attrs->{'+columns'}, delete $attrs->{include_columns})
439 if exists $attrs->{include_columns};
441 # Keep the X vs +X separation until _resolved_attrs time - this allows to
442 # delay the decision on whether to use a default select list ($rsrc->columns)
443 # allowing stuff like the remove_columns helper to work
445 # select/as +select/+as pairs need special handling - the amount of select/as
446 # elements in each pair does *not* have to be equal (think multicolumn
447 # selectors like distinct(foo, bar) ). If the selector is bare (no 'as'
448 # supplied at all) - try to infer the alias, either from the -as parameter
449 # of the selector spec, or use the parameter whole if it looks like a column
450 # name (ugly legacy heuristic). If all fails - leave the selector bare (which
451 # is ok as well), but transport it over a separate attribute to make sure it is
452 # the last thing in the select list, thus unable to throw off the corresponding
454 for my $pref ('', '+') {
456 my ($sel, $as) = map {
457 my $key = "${pref}${_}";
459 my $val = [ ref $attrs->{$key} eq 'ARRAY'
461 : $attrs->{$key} || ()
463 delete $attrs->{$key};
467 if (! @$as and ! @$sel ) {
470 elsif (@$as and ! @$sel) {
471 $self->throw_exception(
472 "Unable to handle ${pref}as specification (@$as) without a corresponding ${pref}select"
476 # no as part supplied at all - try to deduce
477 # if any @$as has been supplied we assume the user knows what (s)he is doing
478 # and blindly keep stacking up pieces
479 my (@new_sel, @new_trailing);
481 if ( ref $_ eq 'HASH' and exists $_->{-as} ) {
482 push @$as, $_->{-as};
485 # assume any plain no-space, no-parenthesis string to be a column spec
486 # FIXME - this is retarded but is necessary to support shit like 'count(foo)'
487 elsif ( ! ref $_ and $_ =~ /^ [^\s\(\)]+ $/x) {
491 # if all else fails - shove the selection to the trailing stack and move on
493 push @new_trailing, $_;
498 $attrs->{"${pref}_trailing_select"} = $self->_merge_attr($attrs->{"${pref}_trailing_select"}, \@new_trailing)
501 elsif (@$as < @$sel) {
502 $self->throw_exception(
503 "Unable to handle an ${pref}as specification (@$as) with less elements than the corresponding ${pref}select"
507 # now see what the result for this pair looks like:
510 # if balanced - treat as a columns entry
511 $attrs->{"${pref}columns"} = $self->_merge_attr(
512 $attrs->{"${pref}columns"},
513 [ map { +{ $as->[$_] => $sel->[$_] } } ( 0 .. $#$as ) ]
517 # unbalanced - shove in select/as, not subject to deduplication in _resolved_attrs
518 $attrs->{"${pref}select"} = $self->_merge_attr($attrs->{"${pref}select"}, $sel);
519 $attrs->{"${pref}as"} = $self->_merge_attr($attrs->{"${pref}as"}, $as);
526 my ($self, $left, $right) = @_;
527 if (defined $left xor defined $right) {
528 return defined $left ? $left : $right;
530 elsif (defined $left) {
531 return { -and => [ map
532 { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
540 =head2 search_literal
544 =item Arguments: $sql_fragment, @bind_values
546 =item Return Value: $resultset (scalar context) || @row_objs (list context)
550 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
551 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
553 Pass a literal chunk of SQL to be added to the conditional part of the
556 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
557 only be used in that context. C<search_literal> is a convenience method.
558 It is equivalent to calling $schema->search(\[]), but if you want to ensure
559 columns are bound correctly, use C<search>.
561 Example of how to use C<search> instead of C<search_literal>
563 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
564 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
567 See L<DBIx::Class::Manual::Cookbook/Searching> and
568 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
569 require C<search_literal>.
574 my ($self, $sql, @bind) = @_;
576 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
579 return $self->search(\[ $sql, map [ __DUMMY__ => $_ ], @bind ], ($attr || () ));
586 =item Arguments: \%columns_values | @pk_values, \%attrs?
588 =item Return Value: $row_object | undef
592 Finds and returns a single row based on supplied criteria. Takes either a
593 hashref with the same format as L</create> (including inference of foreign
594 keys from related objects), or a list of primary key values in the same
595 order as the L<primary columns|DBIx::Class::ResultSource/primary_columns>
596 declaration on the L</result_source>.
598 In either case an attempt is made to combine conditions already existing on
599 the resultset with the condition passed to this method.
601 To aid with preparing the correct query for the storage you may supply the
602 C<key> attribute, which is the name of a
603 L<unique constraint|DBIx::Class::ResultSource/add_unique_constraint> (the
604 unique constraint corresponding to the
605 L<primary columns|DBIx::Class::ResultSource/primary_columns> is always named
606 C<primary>). If the C<key> attribute has been supplied, and DBIC is unable
607 to construct a query that satisfies the named unique constraint fully (
608 non-NULL values for each column member of the constraint) an exception is
611 If no C<key> is specified, the search is carried over all unique constraints
612 which are fully defined by the available condition.
614 If no such constraint is found, C<find> currently defaults to a simple
615 C<< search->(\%column_values) >> which may or may not do what you expect.
616 Note that this fallback behavior may be deprecated in further versions. If
617 you need to search with arbitrary conditions - use L</search>. If the query
618 resulting from this fallback produces more than one row, a warning to the
619 effect is issued, though only the first row is constructed and returned as
622 In addition to C<key>, L</find> recognizes and applies standard
623 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
625 Note that if you have extra concerns about the correctness of the resulting
626 query you need to specify the C<key> attribute and supply the entire condition
627 as an argument to find (since it is not always possible to perform the
628 combination of the resultset condition with the supplied one, especially if
629 the resultset condition contains literal sql).
631 For example, to find a row by its primary key:
633 my $cd = $schema->resultset('CD')->find(5);
635 You can also find a row by a specific unique constraint:
637 my $cd = $schema->resultset('CD')->find(
639 artist => 'Massive Attack',
640 title => 'Mezzanine',
642 { key => 'cd_artist_title' }
645 See also L</find_or_create> and L</update_or_create>.
651 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
653 my $rsrc = $self->result_source;
655 # Parse out the condition from input
657 if (ref $_[0] eq 'HASH') {
658 $call_cond = { %{$_[0]} };
661 my $constraint = exists $attrs->{key} ? $attrs->{key} : 'primary';
662 my @c_cols = $rsrc->unique_constraint_columns($constraint);
664 $self->throw_exception(
665 "No constraint columns, maybe a malformed '$constraint' constraint?"
668 $self->throw_exception (
669 'find() expects either a column/value hashref, or a list of values '
670 . "corresponding to the columns of the specified unique constraint '$constraint'"
671 ) unless @c_cols == @_;
674 @{$call_cond}{@c_cols} = @_;
678 for my $key (keys %$call_cond) {
680 my $keyref = ref($call_cond->{$key})
682 my $relinfo = $rsrc->relationship_info($key)
684 my $val = delete $call_cond->{$key};
686 next if $keyref eq 'ARRAY'; # has_many for multi_create
688 my $rel_q = $rsrc->_resolve_condition(
689 $relinfo->{cond}, $val, $key, $key
691 die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
692 @related{keys %$rel_q} = values %$rel_q;
696 # relationship conditions take precedence (?)
697 @{$call_cond}{keys %related} = values %related;
699 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
701 if (exists $attrs->{key}) {
702 $final_cond = $self->_qualify_cond_columns (
704 $self->_build_unique_cond (
712 elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
713 # This means that we got here after a merger of relationship conditions
714 # in ::Relationship::Base::search_related (the row method), and furthermore
715 # the relationship is of the 'single' type. This means that the condition
716 # provided by the relationship (already attached to $self) is sufficient,
717 # as there can be only one row in the database that would satisfy the
721 # no key was specified - fall down to heuristics mode:
722 # run through all unique queries registered on the resultset, and
723 # 'OR' all qualifying queries together
724 my (@unique_queries, %seen_column_combinations);
725 for my $c_name ($rsrc->unique_constraint_names) {
726 next if $seen_column_combinations{
727 join "\x00", sort $rsrc->unique_constraint_columns($c_name)
730 push @unique_queries, try {
731 $self->_build_unique_cond ($c_name, $call_cond, 'croak_on_nulls')
735 $final_cond = @unique_queries
736 ? [ map { $self->_qualify_cond_columns($_, $alias) } @unique_queries ]
737 : $self->_non_unique_find_fallback ($call_cond, $attrs)
741 # Run the query, passing the result_class since it should propagate for find
742 my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs});
743 if (keys %{$rs->_resolved_attrs->{collapse}}) {
745 carp "Query returned more than one row" if $rs->next;
753 # This is a stop-gap method as agreed during the discussion on find() cleanup:
754 # http://lists.scsys.co.uk/pipermail/dbix-class/2010-October/009535.html
756 # It is invoked when find() is called in legacy-mode with insufficiently-unique
757 # condition. It is provided for overrides until a saner way forward is devised
759 # *NOTE* This is not a public method, and it's *GUARANTEED* to disappear down
760 # the road. Please adjust your tests accordingly to catch this situation early
761 # DBIx::Class::ResultSet->can('_non_unique_find_fallback') is reasonable
763 # The method will not be removed without an adequately complete replacement
764 # for strict-mode enforcement
765 sub _non_unique_find_fallback {
766 my ($self, $cond, $attrs) = @_;
768 return $self->_qualify_cond_columns(
770 exists $attrs->{alias}
772 : $self->{attrs}{alias}
777 sub _qualify_cond_columns {
778 my ($self, $cond, $alias) = @_;
780 my %aliased = %$cond;
781 for (keys %aliased) {
782 $aliased{"$alias.$_"} = delete $aliased{$_}
789 sub _build_unique_cond {
790 my ($self, $constraint_name, $extra_cond, $croak_on_null) = @_;
792 my @c_cols = $self->result_source->unique_constraint_columns($constraint_name);
794 # combination may fail if $self->{cond} is non-trivial
795 my ($final_cond) = try {
796 $self->_merge_with_rscond ($extra_cond)
801 # trim out everything not in $columns
802 $final_cond = { map {
803 exists $final_cond->{$_}
804 ? ( $_ => $final_cond->{$_} )
808 if (my @missing = grep
809 { ! ($croak_on_null ? defined $final_cond->{$_} : exists $final_cond->{$_}) }
812 $self->throw_exception( sprintf ( "Unable to satisfy requested constraint '%s', no values for column(s): %s",
814 join (', ', map { "'$_'" } @missing),
821 !$ENV{DBIC_NULLABLE_KEY_NOWARN}
823 my @undefs = grep { ! defined $final_cond->{$_} } (keys %$final_cond)
825 carp_unique ( sprintf (
826 "NULL/undef values supplied for requested unique constraint '%s' (NULL "
827 . 'values in column(s): %s). This is almost certainly not what you wanted, '
828 . 'though you can set DBIC_NULLABLE_KEY_NOWARN to disable this warning.',
830 join (', ', map { "'$_'" } @undefs),
837 =head2 search_related
841 =item Arguments: $rel, $cond, \%attrs?
843 =item Return Value: $new_resultset (scalar context) || @row_objs (list context)
847 $new_rs = $cd_rs->search_related('artist', {
851 Searches the specified relationship, optionally specifying a condition and
852 attributes for matching records. See L</ATTRIBUTES> for more information.
854 In list context, C<< ->all() >> is called implicitly on the resultset, thus
855 returning a list of row objects instead. To avoid that, use L</search_related_rs>.
857 See also L</search_related_rs>.
862 return shift->related_resultset(shift)->search(@_);
865 =head2 search_related_rs
867 This method works exactly the same as search_related, except that
868 it guarantees a resultset, even in list context.
872 sub search_related_rs {
873 return shift->related_resultset(shift)->search_rs(@_);
880 =item Arguments: none
882 =item Return Value: $cursor
886 Returns a storage-driven cursor to the given resultset. See
887 L<DBIx::Class::Cursor> for more information.
894 my $attrs = $self->_resolved_attrs_copy;
896 return $self->{cursor}
897 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
898 $attrs->{where},$attrs);
905 =item Arguments: $cond?
907 =item Return Value: $row_object | undef
911 my $cd = $schema->resultset('CD')->single({ year => 2001 });
913 Inflates the first result without creating a cursor if the resultset has
914 any records in it; if not returns C<undef>. Used by L</find> as a lean version
917 While this method can take an optional search condition (just like L</search>)
918 being a fast-code-path it does not recognize search attributes. If you need to
919 add extra joins or similar, call L</search> and then chain-call L</single> on the
920 L<DBIx::Class::ResultSet> returned.
926 As of 0.08100, this method enforces the assumption that the preceding
927 query returns only one row. If more than one row is returned, you will receive
930 Query returned more than one row
932 In this case, you should be using L</next> or L</find> instead, or if you really
933 know what you are doing, use the L</rows> attribute to explicitly limit the size
936 This method will also throw an exception if it is called on a resultset prefetching
937 has_many, as such a prefetch implies fetching multiple rows from the database in
938 order to assemble the resulting object.
945 my ($self, $where) = @_;
947 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
950 my $attrs = $self->_resolved_attrs_copy;
952 if (keys %{$attrs->{collapse}}) {
953 $self->throw_exception(
954 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
959 if (defined $attrs->{where}) {
962 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
963 $where, delete $attrs->{where} ]
966 $attrs->{where} = $where;
970 my @data = $self->result_source->storage->select_single(
971 $attrs->{from}, $attrs->{select},
972 $attrs->{where}, $attrs
975 return (@data ? ($self->_construct_object(@data))[0] : undef);
981 # Recursively collapse the query, accumulating values for each column.
983 sub _collapse_query {
984 my ($self, $query, $collapsed) = @_;
988 if (ref $query eq 'ARRAY') {
989 foreach my $subquery (@$query) {
990 next unless ref $subquery; # -or
991 $collapsed = $self->_collapse_query($subquery, $collapsed);
994 elsif (ref $query eq 'HASH') {
995 if (keys %$query and (keys %$query)[0] eq '-and') {
996 foreach my $subquery (@{$query->{-and}}) {
997 $collapsed = $self->_collapse_query($subquery, $collapsed);
1001 foreach my $col (keys %$query) {
1002 my $value = $query->{$col};
1003 $collapsed->{$col}{$value}++;
1015 =item Arguments: $cond?
1017 =item Return Value: $resultsetcolumn
1021 my $max_length = $rs->get_column('length')->max;
1023 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
1028 my ($self, $column) = @_;
1029 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
1037 =item Arguments: $cond, \%attrs?
1039 =item Return Value: $resultset (scalar context) || @row_objs (list context)
1043 # WHERE title LIKE '%blue%'
1044 $cd_rs = $rs->search_like({ title => '%blue%'});
1046 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
1047 that this is simply a convenience method retained for ex Class::DBI users.
1048 You most likely want to use L</search> with specific operators.
1050 For more information, see L<DBIx::Class::Manual::Cookbook>.
1052 This method is deprecated and will be removed in 0.09. Use L</search()>
1053 instead. An example conversion is:
1055 ->search_like({ foo => 'bar' });
1059 ->search({ foo => { like => 'bar' } });
1066 'search_like() is deprecated and will be removed in DBIC version 0.09.'
1067 .' Instead use ->search({ x => { -like => "y%" } })'
1068 .' (note the outer pair of {}s - they are important!)'
1070 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1071 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
1072 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
1073 return $class->search($query, { %$attrs });
1080 =item Arguments: $first, $last
1082 =item Return Value: $resultset (scalar context) || @row_objs (list context)
1086 Returns a resultset or object list representing a subset of elements from the
1087 resultset slice is called on. Indexes are from 0, i.e., to get the first
1088 three records, call:
1090 my ($one, $two, $three) = $rs->slice(0, 2);
1095 my ($self, $min, $max) = @_;
1096 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
1097 $attrs->{offset} = $self->{attrs}{offset} || 0;
1098 $attrs->{offset} += $min;
1099 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
1100 return $self->search(undef, $attrs);
1101 #my $slice = (ref $self)->new($self->result_source, $attrs);
1102 #return (wantarray ? $slice->all : $slice);
1109 =item Arguments: none
1111 =item Return Value: $result | undef
1115 Returns the next element in the resultset (C<undef> is there is none).
1117 Can be used to efficiently iterate over records in the resultset:
1119 my $rs = $schema->resultset('CD')->search;
1120 while (my $cd = $rs->next) {
1124 Note that you need to store the resultset object, and call C<next> on it.
1125 Calling C<< resultset('Table')->next >> repeatedly will always return the
1126 first record from the resultset.
1132 if (my $cache = $self->get_cache) {
1133 $self->{all_cache_position} ||= 0;
1134 return $cache->[$self->{all_cache_position}++];
1136 if ($self->{attrs}{cache}) {
1137 delete $self->{pager};
1138 $self->{all_cache_position} = 1;
1139 return ($self->all)[0];
1141 if ($self->{stashed_objects}) {
1142 my $obj = shift(@{$self->{stashed_objects}});
1143 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
1147 exists $self->{stashed_row}
1148 ? @{delete $self->{stashed_row}}
1149 : $self->cursor->next
1151 return undef unless (@row);
1152 my ($row, @more) = $self->_construct_object(@row);
1153 $self->{stashed_objects} = \@more if @more;
1157 sub _construct_object {
1158 my ($self, @row) = @_;
1160 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row)
1162 my @new = $self->result_class->inflate_result($self->result_source, @$info);
1163 @new = $self->{_attrs}{record_filter}->(@new)
1164 if exists $self->{_attrs}{record_filter};
1168 sub _collapse_result {
1169 my ($self, $as_proto, $row) = @_;
1173 # 'foo' => [ undef, 'foo' ]
1174 # 'foo.bar' => [ 'foo', 'bar' ]
1175 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
1177 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
1179 my %collapse = %{$self->{_attrs}{collapse}||{}};
1183 # if we're doing collapsing (has_many prefetch) we need to grab records
1184 # until the PK changes, so fill @pri_index. if not, we leave it empty so
1185 # we know we don't have to bother.
1187 # the reason for not using the collapse stuff directly is because if you
1188 # had for e.g. two artists in a row with no cds, the collapse info for
1189 # both would be NULL (undef) so you'd lose the second artist
1191 # store just the index so we can check the array positions from the row
1192 # without having to contruct the full hash
1194 if (keys %collapse) {
1195 my %pri = map { ($_ => 1) } $self->result_source->_pri_cols;
1196 foreach my $i (0 .. $#construct_as) {
1197 next if defined($construct_as[$i][0]); # only self table
1198 if (delete $pri{$construct_as[$i][1]}) {
1199 push(@pri_index, $i);
1201 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1205 # no need to do an if, it'll be empty if @pri_index is empty anyway
1207 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1211 do { # no need to check anything at the front, we always want the first row
1215 foreach my $this_as (@construct_as) {
1216 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1219 push(@const_rows, \%const);
1221 } until ( # no pri_index => no collapse => drop straight out
1224 do { # get another row, stash it, drop out if different PK
1226 @copy = $self->cursor->next;
1227 $self->{stashed_row} = \@copy;
1229 # last thing in do block, counts as true if anything doesn't match
1231 # check xor defined first for NULL vs. NOT NULL then if one is
1232 # defined the other must be so check string equality
1235 (defined $pri_vals{$_} ^ defined $copy[$_])
1236 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1241 my $alias = $self->{attrs}{alias};
1248 foreach my $const (@const_rows) {
1249 scalar @const_keys or do {
1250 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1252 foreach my $key (@const_keys) {
1255 my @parts = split(/\./, $key);
1257 my $data = $const->{$key};
1258 foreach my $p (@parts) {
1259 $target = $target->[1]->{$p} ||= [];
1261 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1262 # collapsing at this point and on final part
1263 my $pos = $collapse_pos{$cur};
1264 CK: foreach my $ck (@ckey) {
1265 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1266 $collapse_pos{$cur} = $data;
1267 delete @collapse_pos{ # clear all positioning for sub-entries
1268 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1275 if (exists $collapse{$cur}) {
1276 $target = $target->[-1];
1279 $target->[0] = $data;
1281 $info->[0] = $const->{$key};
1289 =head2 result_source
1293 =item Arguments: $result_source?
1295 =item Return Value: $result_source
1299 An accessor for the primary ResultSource object from which this ResultSet
1306 =item Arguments: $result_class?
1308 =item Return Value: $result_class
1312 An accessor for the class to use when creating row objects. Defaults to
1313 C<< result_source->result_class >> - which in most cases is the name of the
1314 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1316 Note that changing the result_class will also remove any components
1317 that were originally loaded in the source class via
1318 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1319 in the original source class will not run.
1324 my ($self, $result_class) = @_;
1325 if ($result_class) {
1326 unless (ref $result_class) { # don't fire this for an object
1327 $self->ensure_class_loaded($result_class);
1329 $self->_result_class($result_class);
1330 # THIS LINE WOULD BE A BUG - this accessor specifically exists to
1331 # permit the user to set result class on one result set only; it only
1332 # chains if provided to search()
1333 #$self->{attrs}{result_class} = $result_class if ref $self;
1335 $self->_result_class;
1342 =item Arguments: $cond, \%attrs??
1344 =item Return Value: $count
1348 Performs an SQL C<COUNT> with the same query as the resultset was built
1349 with to find the number of elements. Passing arguments is equivalent to
1350 C<< $rs->search ($cond, \%attrs)->count >>
1356 return $self->search(@_)->count if @_ and defined $_[0];
1357 return scalar @{ $self->get_cache } if $self->get_cache;
1359 my $attrs = $self->_resolved_attrs_copy;
1361 # this is a little optimization - it is faster to do the limit
1362 # adjustments in software, instead of a subquery
1363 my $rows = delete $attrs->{rows};
1364 my $offset = delete $attrs->{offset};
1367 if ($self->_has_resolved_attr (qw/collapse group_by/)) {
1368 $crs = $self->_count_subq_rs ($attrs);
1371 $crs = $self->_count_rs ($attrs);
1373 my $count = $crs->next;
1375 $count -= $offset if $offset;
1376 $count = $rows if $rows and $rows < $count;
1377 $count = 0 if ($count < 0);
1386 =item Arguments: $cond, \%attrs??
1388 =item Return Value: $count_rs
1392 Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
1393 This can be very handy for subqueries:
1395 ->search( { amount => $some_rs->count_rs->as_query } )
1397 As with regular resultsets the SQL query will be executed only after
1398 the resultset is accessed via L</next> or L</all>. That would return
1399 the same single value obtainable via L</count>.
1405 return $self->search(@_)->count_rs if @_;
1407 # this may look like a lack of abstraction (count() does about the same)
1408 # but in fact an _rs *must* use a subquery for the limits, as the
1409 # software based limiting can not be ported if this $rs is to be used
1410 # in a subquery itself (i.e. ->as_query)
1411 if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
1412 return $self->_count_subq_rs;
1415 return $self->_count_rs;
1420 # returns a ResultSetColumn object tied to the count query
1423 my ($self, $attrs) = @_;
1425 my $rsrc = $self->result_source;
1426 $attrs ||= $self->_resolved_attrs;
1428 my $tmp_attrs = { %$attrs };
1429 # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
1430 delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
1432 # overwrite the selector (supplied by the storage)
1433 $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
1434 $tmp_attrs->{as} = 'count';
1435 delete @{$tmp_attrs}{qw/columns _trailing_select/};
1437 my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
1443 # same as above but uses a subquery
1445 sub _count_subq_rs {
1446 my ($self, $attrs) = @_;
1448 my $rsrc = $self->result_source;
1449 $attrs ||= $self->_resolved_attrs;
1451 my $sub_attrs = { %$attrs };
1452 # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
1453 delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range _trailing_select order_by for/};
1455 # if we multi-prefetch we group_by primary keys only as this is what we would
1456 # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
1457 if ( keys %{$attrs->{collapse}} ) {
1458 $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->_pri_cols) ]
1461 # Calculate subquery selector
1462 if (my $g = $sub_attrs->{group_by}) {
1464 my $sql_maker = $rsrc->storage->sql_maker;
1466 # necessary as the group_by may refer to aliased functions
1468 for my $sel (@{$attrs->{select}}) {
1469 $sel_index->{$sel->{-as}} = $sel
1470 if (ref $sel eq 'HASH' and $sel->{-as});
1473 # anything from the original select mentioned on the group-by needs to make it to the inner selector
1474 # also look for named aggregates referred in the having clause
1475 # having often contains scalarrefs - thus parse it out entirely
1477 if ($attrs->{having}) {
1478 local $sql_maker->{having_bind};
1479 local $sql_maker->{quote_char} = $sql_maker->{quote_char};
1480 local $sql_maker->{name_sep} = $sql_maker->{name_sep};
1481 unless (defined $sql_maker->{quote_char} and length $sql_maker->{quote_char}) {
1482 $sql_maker->{quote_char} = [ "\x00", "\xFF" ];
1483 # if we don't unset it we screw up retarded but unfortunately working
1484 # 'MAX(foo.bar)' => { '>', 3 }
1485 $sql_maker->{name_sep} = '';
1488 my ($lquote, $rquote, $sep) = map { quotemeta $_ } ($sql_maker->_quote_chars, $sql_maker->name_sep);
1490 my $sql = $sql_maker->_parse_rs_attrs ({ having => $attrs->{having} });
1492 # search for both a proper quoted qualified string, for a naive unquoted scalarref
1493 # and if all fails for an utterly naive quoted scalar-with-function
1495 $rquote $sep $lquote (.+?) $rquote
1497 [\s,] \w+ \. (\w+) [\s,]
1499 [\s,] $lquote (.+?) $rquote [\s,]
1501 push @parts, ($1 || $2 || $3); # one of them matched if we got here
1506 my $colpiece = $sel_index->{$_} || $_;
1508 # unqualify join-based group_by's. Arcane but possible query
1509 # also horrible horrible hack to alias a column (not a func.)
1510 # (probably need to introduce SQLA syntax)
1511 if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
1514 $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
1516 push @{$sub_attrs->{select}}, $colpiece;
1520 my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
1521 $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
1524 return $rsrc->resultset_class
1525 ->new ($rsrc, $sub_attrs)
1527 ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
1528 ->get_column ('count');
1535 =head2 count_literal
1539 =item Arguments: $sql_fragment, @bind_values
1541 =item Return Value: $count
1545 Counts the results in a literal query. Equivalent to calling L</search_literal>
1546 with the passed arguments, then L</count>.
1550 sub count_literal { shift->search_literal(@_)->count; }
1556 =item Arguments: none
1558 =item Return Value: @objects
1562 Returns all elements in the resultset.
1569 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1572 return @{ $self->get_cache } if $self->get_cache;
1576 if (keys %{$self->_resolved_attrs->{collapse}}) {
1577 # Using $self->cursor->all is really just an optimisation.
1578 # If we're collapsing has_many prefetches it probably makes
1579 # very little difference, and this is cleaner than hacking
1580 # _construct_object to survive the approach
1581 $self->cursor->reset;
1582 my @row = $self->cursor->next;
1584 push(@obj, $self->_construct_object(@row));
1585 @row = (exists $self->{stashed_row}
1586 ? @{delete $self->{stashed_row}}
1587 : $self->cursor->next);
1590 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1593 $self->set_cache(\@obj) if $self->{attrs}{cache};
1602 =item Arguments: none
1604 =item Return Value: $self
1608 Resets the resultset's cursor, so you can iterate through the elements again.
1609 Implicitly resets the storage cursor, so a subsequent L</next> will trigger
1616 delete $self->{_attrs} if exists $self->{_attrs};
1617 $self->{all_cache_position} = 0;
1618 $self->cursor->reset;
1626 =item Arguments: none
1628 =item Return Value: $object | undef
1632 Resets the resultset and returns an object for the first result (or C<undef>
1633 if the resultset is empty).
1638 return $_[0]->reset->next;
1644 # Determines whether and what type of subquery is required for the $rs operation.
1645 # If grouping is necessary either supplies its own, or verifies the current one
1646 # After all is done delegates to the proper storage method.
1648 sub _rs_update_delete {
1649 my ($self, $op, $values) = @_;
1651 my $rsrc = $self->result_source;
1653 # if a condition exists we need to strip all table qualifiers
1654 # if this is not possible we'll force a subquery below
1655 my $cond = $rsrc->schema->storage->_strip_cond_qualifiers ($self->{cond});
1657 my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/);
1658 my $needs_subq = $needs_group_by_subq || (not defined $cond) || $self->_has_resolved_attr(qw/rows offset/);
1660 if ($needs_group_by_subq or $needs_subq) {
1662 # make a new $rs selecting only the PKs (that's all we really need)
1663 my $attrs = $self->_resolved_attrs_copy;
1666 delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_selector_range as/;
1667 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ];
1669 if ($needs_group_by_subq) {
1670 # make sure no group_by was supplied, or if there is one - make sure it matches
1671 # the columns compiled above perfectly. Anything else can not be sanely executed
1672 # on most databases so croak right then and there
1674 if (my $g = $attrs->{group_by}) {
1675 my @current_group_by = map
1676 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1681 join ("\x00", sort @current_group_by)
1683 join ("\x00", sort @{$attrs->{columns}} )
1685 $self->throw_exception (
1686 "You have just attempted a $op operation on a resultset which does group_by"
1687 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1688 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1689 . ' kind of queries. Please retry the operation with a modified group_by or'
1690 . ' without using one at all.'
1695 $attrs->{group_by} = $attrs->{columns};
1699 my $subrs = (ref $self)->new($rsrc, $attrs);
1700 return $self->result_source->storage->_subq_update_delete($subrs, $op, $values);
1703 return $rsrc->storage->$op(
1705 $op eq 'update' ? $values : (),
1715 =item Arguments: \%values
1717 =item Return Value: $storage_rv
1721 Sets the specified columns in the resultset to the supplied values in a
1722 single query. Note that this will not run any accessor/set_column/update
1723 triggers, nor will it update any row object instances derived from this
1724 resultset (this includes the contents of the L<resultset cache|/set_cache>
1725 if any). See L</update_all> if you need to execute any on-update
1726 triggers or cascades defined either by you or a
1727 L<result component|DBIx::Class::Manual::Component/WHAT_IS_A_COMPONENT>.
1729 The return value is a pass through of what the underlying
1730 storage backend returned, and may vary. See L<DBI/execute> for the most
1735 Note that L</update> does not process/deflate any of the values passed in.
1736 This is unlike the corresponding L<DBIx::Class::Row/update>. The user must
1737 ensure manually that any value passed to this method will stringify to
1738 something the RDBMS knows how to deal with. A notable example is the
1739 handling of L<DateTime> objects, for more info see:
1740 L<DBIx::Class::Manual::Cookbook/Formatting_DateTime_objects_in_queries>.
1745 my ($self, $values) = @_;
1746 $self->throw_exception('Values for update must be a hash')
1747 unless ref $values eq 'HASH';
1749 return $self->_rs_update_delete ('update', $values);
1756 =item Arguments: \%values
1758 =item Return Value: 1
1762 Fetches all objects and updates them one at a time via
1763 L<DBIx::Class::Row/update>. Note that C<update_all> will run DBIC defined
1764 triggers, while L</update> will not.
1769 my ($self, $values) = @_;
1770 $self->throw_exception('Values for update_all must be a hash')
1771 unless ref $values eq 'HASH';
1773 my $guard = $self->result_source->schema->txn_scope_guard;
1774 $_->update($values) for $self->all;
1783 =item Arguments: none
1785 =item Return Value: $storage_rv
1789 Deletes the rows matching this resultset in a single query. Note that this
1790 will not run any delete triggers, nor will it alter the
1791 L<in_storage|DBIx::Class::Row/in_storage> status of any row object instances
1792 derived from this resultset (this includes the contents of the
1793 L<resultset cache|/set_cache> if any). See L</delete_all> if you need to
1794 execute any on-delete triggers or cascades defined either by you or a
1795 L<result component|DBIx::Class::Manual::Component/WHAT_IS_A_COMPONENT>.
1797 The return value is a pass through of what the underlying storage backend
1798 returned, and may vary. See L<DBI/execute> for the most common case.
1804 $self->throw_exception('delete does not accept any arguments')
1807 return $self->_rs_update_delete ('delete');
1814 =item Arguments: none
1816 =item Return Value: 1
1820 Fetches all objects and deletes them one at a time via
1821 L<DBIx::Class::Row/delete>. Note that C<delete_all> will run DBIC defined
1822 triggers, while L</delete> will not.
1828 $self->throw_exception('delete_all does not accept any arguments')
1831 my $guard = $self->result_source->schema->txn_scope_guard;
1832 $_->delete for $self->all;
1841 =item Arguments: \@data;
1845 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1846 For the arrayref of hashrefs style each hashref should be a structure suitable
1847 for submitting to a $resultset->create(...) method.
1849 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1850 to insert the data, as this is a faster method.
1852 Otherwise, each set of data is inserted into the database using
1853 L<DBIx::Class::ResultSet/create>, and the resulting objects are
1854 accumulated into an array. The array itself, or an array reference
1855 is returned depending on scalar or list context.
1857 Example: Assuming an Artist Class that has many CDs Classes relating:
1859 my $Artist_rs = $schema->resultset("Artist");
1861 ## Void Context Example
1862 $Artist_rs->populate([
1863 { artistid => 4, name => 'Manufactured Crap', cds => [
1864 { title => 'My First CD', year => 2006 },
1865 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1868 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1869 { title => 'My parents sold me to a record company', year => 2005 },
1870 { title => 'Why Am I So Ugly?', year => 2006 },
1871 { title => 'I Got Surgery and am now Popular', year => 2007 }
1876 ## Array Context Example
1877 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1878 { name => "Artist One"},
1879 { name => "Artist Two"},
1880 { name => "Artist Three", cds=> [
1881 { title => "First CD", year => 2007},
1882 { title => "Second CD", year => 2008},
1886 print $ArtistOne->name; ## response is 'Artist One'
1887 print $ArtistThree->cds->count ## reponse is '2'
1889 For the arrayref of arrayrefs style, the first element should be a list of the
1890 fieldsnames to which the remaining elements are rows being inserted. For
1893 $Arstist_rs->populate([
1894 [qw/artistid name/],
1895 [100, 'A Formally Unknown Singer'],
1896 [101, 'A singer that jumped the shark two albums ago'],
1897 [102, 'An actually cool singer'],
1900 Please note an important effect on your data when choosing between void and
1901 wantarray context. Since void context goes straight to C<insert_bulk> in
1902 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1903 C<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1904 create primary keys for you, you will find that your PKs are empty. In this
1905 case you will have to use the wantarray context in order to create those
1913 # cruft placed in standalone method
1914 my $data = $self->_normalize_populate_args(@_);
1916 if(defined wantarray) {
1918 foreach my $item (@$data) {
1919 push(@created, $self->create($item));
1921 return wantarray ? @created : \@created;
1924 my $first = $data->[0];
1926 # if a column is a registered relationship, and is a non-blessed hash/array, consider
1927 # it relationship data
1928 my (@rels, @columns);
1929 my $rsrc = $self->result_source;
1930 my $rels = { map { $_ => $rsrc->relationship_info($_) } $rsrc->relationships };
1931 for (keys %$first) {
1932 my $ref = ref $first->{$_};
1933 $rels->{$_} && ($ref eq 'ARRAY' or $ref eq 'HASH')
1939 my @pks = $rsrc->primary_columns;
1941 ## do the belongs_to relationships
1942 foreach my $index (0..$#$data) {
1944 # delegate to create() for any dataset without primary keys with specified relationships
1945 if (grep { !defined $data->[$index]->{$_} } @pks ) {
1947 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
1948 my @ret = $self->populate($data);
1954 foreach my $rel (@rels) {
1955 next unless ref $data->[$index]->{$rel} eq "HASH";
1956 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1957 my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
1958 my $related = $result->result_source->_resolve_condition(
1959 $reverse_relinfo->{cond},
1965 delete $data->[$index]->{$rel};
1966 $data->[$index] = {%{$data->[$index]}, %$related};
1968 push @columns, keys %$related if $index == 0;
1972 ## inherit the data locked in the conditions of the resultset
1973 my ($rs_data) = $self->_merge_with_rscond({});
1974 delete @{$rs_data}{@columns};
1975 my @inherit_cols = keys %$rs_data;
1976 my @inherit_data = values %$rs_data;
1978 ## do bulk insert on current row
1979 $rsrc->storage->insert_bulk(
1981 [@columns, @inherit_cols],
1982 [ map { [ @$_{@columns}, @inherit_data ] } @$data ],
1985 ## do the has_many relationships
1986 foreach my $item (@$data) {
1990 foreach my $rel (@rels) {
1991 next unless ref $item->{$rel} eq "ARRAY" && @{ $item->{$rel} };
1993 $main_row ||= $self->new_result({map { $_ => $item->{$_} } @pks});
1995 my $child = $main_row->$rel;
1997 my $related = $child->result_source->_resolve_condition(
1998 $rels->{$rel}{cond},
2004 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
2005 my @populate = map { {%$_, %$related} } @rows_to_add;
2007 $child->populate( \@populate );
2014 # populate() argumnets went over several incarnations
2015 # What we ultimately support is AoH
2016 sub _normalize_populate_args {
2017 my ($self, $arg) = @_;
2019 if (ref $arg eq 'ARRAY') {
2020 if (ref $arg->[0] eq 'HASH') {
2023 elsif (ref $arg->[0] eq 'ARRAY') {
2025 my @colnames = @{$arg->[0]};
2026 foreach my $values (@{$arg}[1 .. $#$arg]) {
2027 push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
2033 $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
2040 =item Arguments: none
2042 =item Return Value: $pager
2046 Return Value a L<Data::Page> object for the current resultset. Only makes
2047 sense for queries with a C<page> attribute.
2049 To get the full count of entries for a paged resultset, call
2050 C<total_entries> on the L<Data::Page> object.
2054 # make a wizard good for both a scalar and a hashref
2055 my $mk_lazy_count_wizard = sub {
2056 require Variable::Magic;
2058 my $stash = { total_rs => shift };
2059 my $slot = shift; # only used by the hashref magic
2061 my $magic = Variable::Magic::wizard (
2062 data => sub { $stash },
2068 # set value lazily, and dispell for good
2069 ${$_[0]} = $_[1]{total_rs}->count;
2070 Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref});
2074 # an explicit set implies dispell as well
2075 # the unless() is to work around "fun and giggles" below
2076 Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref})
2077 unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
2084 if ($_[2] eq $slot and !$_[1]{inactive}) {
2085 my $cnt = $_[1]{total_rs}->count;
2086 $_[0]->{$slot} = $cnt;
2088 # attempting to dispell in a fetch handle (works in store), seems
2089 # to invariable segfault on 5.10, 5.12, 5.13 :(
2090 # so use an inactivator instead
2091 #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
2097 if (! $_[1]{inactive} and $_[2] eq $slot) {
2098 #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
2100 unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
2107 $stash->{magic_selfref} = $magic;
2108 weaken ($stash->{magic_selfref}); # this fails on 5.8.1
2113 # the tie class for 5.8.1
2115 package # hide from pause
2116 DBIx::Class::__DBIC_LAZY_RS_COUNT__;
2117 use base qw/Tie::Hash/;
2119 sub FIRSTKEY { my $dummy = scalar keys %{$_[0]{data}}; each %{$_[0]{data}} }
2120 sub NEXTKEY { each %{$_[0]{data}} }
2121 sub EXISTS { exists $_[0]{data}{$_[1]} }
2122 sub DELETE { delete $_[0]{data}{$_[1]} }
2123 sub CLEAR { %{$_[0]{data}} = () }
2124 sub SCALAR { scalar %{$_[0]{data}} }
2127 $_[1]{data} = {%{$_[1]{selfref}}};
2128 %{$_[1]{selfref}} = ();
2129 Scalar::Util::weaken ($_[1]{selfref});
2130 return bless ($_[1], $_[0]);
2134 if ($_[1] eq $_[0]{slot}) {
2135 my $cnt = $_[0]{data}{$_[1]} = $_[0]{total_rs}->count;
2136 untie %{$_[0]{selfref}};
2137 %{$_[0]{selfref}} = %{$_[0]{data}};
2146 $_[0]{data}{$_[1]} = $_[2];
2147 if ($_[1] eq $_[0]{slot}) {
2148 untie %{$_[0]{selfref}};
2149 %{$_[0]{selfref}} = %{$_[0]{data}};
2158 return $self->{pager} if $self->{pager};
2160 my $attrs = $self->{attrs};
2161 if (!defined $attrs->{page}) {
2162 $self->throw_exception("Can't create pager for non-paged rs");
2164 elsif ($attrs->{page} <= 0) {
2165 $self->throw_exception('Invalid page number (page-numbers are 1-based)');
2167 $attrs->{rows} ||= 10;
2169 # throw away the paging flags and re-run the count (possibly
2170 # with a subselect) to get the real total count
2171 my $count_attrs = { %$attrs };
2172 delete $count_attrs->{$_} for qw/rows offset page pager/;
2173 my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
2176 ### the following may seem awkward and dirty, but it's a thought-experiment
2177 ### necessary for future development of DBIx::DS. Do *NOT* change this code
2178 ### before talking to ribasushi/mst
2181 my $pager = Data::Page->new(
2182 0, #start with an empty set
2184 $self->{attrs}{page},
2187 my $data_slot = 'total_entries';
2189 # Since we are interested in a cached value (once it's set - it's set), every
2190 # technique will detach from the magic-host once the time comes to fire the
2191 # ->count (or in the segfaulting case of >= 5.10 it will deactivate itself)
2193 if ($] < 5.008003) {
2194 # 5.8.1 throws 'Modification of a read-only value attempted' when one tries
2195 # to weakref the magic container :(
2197 tie (%$pager, 'DBIx::Class::__DBIC_LAZY_RS_COUNT__',
2198 { slot => $data_slot, total_rs => $total_rs, selfref => $pager }
2201 elsif ($] < 5.010) {
2202 # We can use magic on the hash value slot. It's interesting that the magic is
2203 # attached to the hash-slot, and does *not* stop working once I do the dummy
2204 # assignments after the cast()
2205 # tested on 5.8.3 and 5.8.9
2206 my $magic = $mk_lazy_count_wizard->($total_rs);
2207 Variable::Magic::cast ( $pager->{$data_slot}, $magic );
2209 # this is for fun and giggles
2210 $pager->{$data_slot} = -1;
2211 $pager->{$data_slot} = 0;
2213 # this does not work for scalars, but works with
2215 #my %vals = %$pager;
2220 # And the uvar magic
2221 # works on 5.10.1, 5.12.1 and 5.13.4 in its current form,
2222 # however see the wizard maker for more notes
2223 my $magic = $mk_lazy_count_wizard->($total_rs, $data_slot);
2224 Variable::Magic::cast ( %$pager, $magic );
2227 $pager->{$data_slot} = -1;
2228 $pager->{$data_slot} = 0;
2236 return $self->{pager} = $pager;
2243 =item Arguments: $page_number
2245 =item Return Value: $rs
2249 Returns a resultset for the $page_number page of the resultset on which page
2250 is called, where each page contains a number of rows equal to the 'rows'
2251 attribute set on the resultset (10 by default).
2256 my ($self, $page) = @_;
2257 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
2264 =item Arguments: \%vals
2266 =item Return Value: $rowobject
2270 Creates a new row object in the resultset's result class and returns
2271 it. The row is not inserted into the database at this point, call
2272 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
2273 will tell you whether the row object has been inserted or not.
2275 Passes the hashref of input on to L<DBIx::Class::Row/new>.
2280 my ($self, $values) = @_;
2281 $self->throw_exception( "new_result needs a hash" )
2282 unless (ref $values eq 'HASH');
2284 my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
2288 @$cols_from_relations
2289 ? (-cols_from_relations => $cols_from_relations)
2291 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
2294 return $self->result_class->new(\%new);
2297 # _merge_with_rscond
2299 # Takes a simple hash of K/V data and returns its copy merged with the
2300 # condition already present on the resultset. Additionally returns an
2301 # arrayref of value/condition names, which were inferred from related
2302 # objects (this is needed for in-memory related objects)
2303 sub _merge_with_rscond {
2304 my ($self, $data) = @_;
2306 my (%new_data, @cols_from_relations);
2308 my $alias = $self->{attrs}{alias};
2310 if (! defined $self->{cond}) {
2311 # just massage $data below
2313 elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
2314 %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
2315 @cols_from_relations = keys %new_data;
2317 elsif (ref $self->{cond} ne 'HASH') {
2318 $self->throw_exception(
2319 "Can't abstract implicit construct, resultset condition not a hash"
2323 # precendence must be given to passed values over values inherited from
2324 # the cond, so the order here is important.
2325 my $collapsed_cond = $self->_collapse_cond($self->{cond});
2326 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
2328 while ( my($col, $value) = each %implied ) {
2329 my $vref = ref $value;
2335 (keys %$value)[0] eq '='
2337 $new_data{$col} = $value->{'='};
2339 elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
2340 $new_data{$col} = $value;
2347 %{ $self->_remove_alias($data, $alias) },
2350 return (\%new_data, \@cols_from_relations);
2353 # _has_resolved_attr
2355 # determines if the resultset defines at least one
2356 # of the attributes supplied
2358 # used to determine if a subquery is neccessary
2360 # supports some virtual attributes:
2362 # This will scan for any joins being present on the resultset.
2363 # It is not a mere key-search but a deep inspection of {from}
2366 sub _has_resolved_attr {
2367 my ($self, @attr_names) = @_;
2369 my $attrs = $self->_resolved_attrs;
2373 for my $n (@attr_names) {
2374 if (grep { $n eq $_ } (qw/-join/) ) {
2375 $extra_checks{$n}++;
2379 my $attr = $attrs->{$n};
2381 next if not defined $attr;
2383 if (ref $attr eq 'HASH') {
2384 return 1 if keys %$attr;
2386 elsif (ref $attr eq 'ARRAY') {
2394 # a resolved join is expressed as a multi-level from
2396 $extra_checks{-join}
2398 ref $attrs->{from} eq 'ARRAY'
2400 @{$attrs->{from}} > 1
2408 # Recursively collapse the condition.
2410 sub _collapse_cond {
2411 my ($self, $cond, $collapsed) = @_;
2415 if (ref $cond eq 'ARRAY') {
2416 foreach my $subcond (@$cond) {
2417 next unless ref $subcond; # -or
2418 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2421 elsif (ref $cond eq 'HASH') {
2422 if (keys %$cond and (keys %$cond)[0] eq '-and') {
2423 foreach my $subcond (@{$cond->{-and}}) {
2424 $collapsed = $self->_collapse_cond($subcond, $collapsed);
2428 foreach my $col (keys %$cond) {
2429 my $value = $cond->{$col};
2430 $collapsed->{$col} = $value;
2440 # Remove the specified alias from the specified query hash. A copy is made so
2441 # the original query is not modified.
2444 my ($self, $query, $alias) = @_;
2446 my %orig = %{ $query || {} };
2449 foreach my $key (keys %orig) {
2451 $unaliased{$key} = $orig{$key};
2454 $unaliased{$1} = $orig{$key}
2455 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
2465 =item Arguments: none
2467 =item Return Value: \[ $sql, @bind ]
2471 Returns the SQL query and bind vars associated with the invocant.
2473 This is generally used as the RHS for a subquery.
2480 my $attrs = $self->_resolved_attrs_copy;
2485 # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
2486 # $sql also has no wrapping parenthesis in list ctx
2488 my $sqlbind = $self->result_source->storage
2489 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
2498 =item Arguments: \%vals, \%attrs?
2500 =item Return Value: $rowobject
2504 my $artist = $schema->resultset('Artist')->find_or_new(
2505 { artist => 'fred' }, { key => 'artists' });
2507 $cd->cd_to_producer->find_or_new({ producer => $producer },
2508 { key => 'primary });
2510 Find an existing record from this resultset using L</find>. if none exists,
2511 instantiate a new result object and return it. The object will not be saved
2512 into your storage until you call L<DBIx::Class::Row/insert> on it.
2514 You most likely want this method when looking for existing rows using a unique
2515 constraint that is not the primary key, or looking for related rows.
2517 If you want objects to be saved immediately, use L</find_or_create> instead.
2519 B<Note>: Make sure to read the documentation of L</find> and understand the
2520 significance of the C<key> attribute, as its lack may skew your search, and
2521 subsequently result in spurious new objects.
2523 B<Note>: Take care when using C<find_or_new> with a table having
2524 columns with default values that you intend to be automatically
2525 supplied by the database (e.g. an auto_increment primary key column).
2526 In normal usage, the value of such columns should NOT be included at
2527 all in the call to C<find_or_new>, even when set to C<undef>.
2533 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2534 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2535 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2538 return $self->new_result($hash);
2545 =item Arguments: \%vals
2547 =item Return Value: a L<DBIx::Class::Row> $object
2551 Attempt to create a single new row or a row with multiple related rows
2552 in the table represented by the resultset (and related tables). This
2553 will not check for duplicate rows before inserting, use
2554 L</find_or_create> to do that.
2556 To create one row for this resultset, pass a hashref of key/value
2557 pairs representing the columns of the table and the values you wish to
2558 store. If the appropriate relationships are set up, foreign key fields
2559 can also be passed an object representing the foreign row, and the
2560 value will be set to its primary key.
2562 To create related objects, pass a hashref of related-object column values
2563 B<keyed on the relationship name>. If the relationship is of type C<multi>
2564 (L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
2565 The process will correctly identify columns holding foreign keys, and will
2566 transparently populate them from the keys of the corresponding relation.
2567 This can be applied recursively, and will work correctly for a structure
2568 with an arbitrary depth and width, as long as the relationships actually
2569 exists and the correct column data has been supplied.
2572 Instead of hashrefs of plain related data (key/value pairs), you may
2573 also pass new or inserted objects. New objects (not inserted yet, see
2574 L</new>), will be inserted into their appropriate tables.
2576 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
2578 Example of creating a new row.
2580 $person_rs->create({
2581 name=>"Some Person",
2582 email=>"somebody@someplace.com"
2585 Example of creating a new row and also creating rows in a related C<has_many>
2586 or C<has_one> resultset. Note Arrayref.
2589 { artistid => 4, name => 'Manufactured Crap', cds => [
2590 { title => 'My First CD', year => 2006 },
2591 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2596 Example of creating a new row and also creating a row in a related
2597 C<belongs_to> resultset. Note Hashref.
2600 title=>"Music for Silly Walks",
2603 name=>"Silly Musician",
2611 When subclassing ResultSet never attempt to override this method. Since
2612 it is a simple shortcut for C<< $self->new_result($attrs)->insert >>, a
2613 lot of the internals simply never call it, so your override will be
2614 bypassed more often than not. Override either L<new|DBIx::Class::Row/new>
2615 or L<insert|DBIx::Class::Row/insert> depending on how early in the
2616 L</create> process you need to intervene.
2623 my ($self, $attrs) = @_;
2624 $self->throw_exception( "create needs a hashref" )
2625 unless ref $attrs eq 'HASH';
2626 return $self->new_result($attrs)->insert;
2629 =head2 find_or_create
2633 =item Arguments: \%vals, \%attrs?
2635 =item Return Value: $rowobject
2639 $cd->cd_to_producer->find_or_create({ producer => $producer },
2640 { key => 'primary' });
2642 Tries to find a record based on its primary key or unique constraints; if none
2643 is found, creates one and returns that instead.
2645 my $cd = $schema->resultset('CD')->find_or_create({
2647 artist => 'Massive Attack',
2648 title => 'Mezzanine',
2652 Also takes an optional C<key> attribute, to search by a specific key or unique
2653 constraint. For example:
2655 my $cd = $schema->resultset('CD')->find_or_create(
2657 artist => 'Massive Attack',
2658 title => 'Mezzanine',
2660 { key => 'cd_artist_title' }
2663 B<Note>: Make sure to read the documentation of L</find> and understand the
2664 significance of the C<key> attribute, as its lack may skew your search, and
2665 subsequently result in spurious row creation.
2667 B<Note>: Because find_or_create() reads from the database and then
2668 possibly inserts based on the result, this method is subject to a race
2669 condition. Another process could create a record in the table after
2670 the find has completed and before the create has started. To avoid
2671 this problem, use find_or_create() inside a transaction.
2673 B<Note>: Take care when using C<find_or_create> with a table having
2674 columns with default values that you intend to be automatically
2675 supplied by the database (e.g. an auto_increment primary key column).
2676 In normal usage, the value of such columns should NOT be included at
2677 all in the call to C<find_or_create>, even when set to C<undef>.
2679 See also L</find> and L</update_or_create>. For information on how to declare
2680 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2684 sub find_or_create {
2686 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2687 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2688 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2691 return $self->create($hash);
2694 =head2 update_or_create
2698 =item Arguments: \%col_values, { key => $unique_constraint }?
2700 =item Return Value: $row_object
2704 $resultset->update_or_create({ col => $val, ... });
2706 Like L</find_or_create>, but if a row is found it is immediately updated via
2707 C<< $found_row->update (\%col_values) >>.
2710 Takes an optional C<key> attribute to search on a specific unique constraint.
2713 # In your application
2714 my $cd = $schema->resultset('CD')->update_or_create(
2716 artist => 'Massive Attack',
2717 title => 'Mezzanine',
2720 { key => 'cd_artist_title' }
2723 $cd->cd_to_producer->update_or_create({
2724 producer => $producer,
2730 B<Note>: Make sure to read the documentation of L</find> and understand the
2731 significance of the C<key> attribute, as its lack may skew your search, and
2732 subsequently result in spurious row creation.
2734 B<Note>: Take care when using C<update_or_create> with a table having
2735 columns with default values that you intend to be automatically
2736 supplied by the database (e.g. an auto_increment primary key column).
2737 In normal usage, the value of such columns should NOT be included at
2738 all in the call to C<update_or_create>, even when set to C<undef>.
2740 See also L</find> and L</find_or_create>. For information on how to declare
2741 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2745 sub update_or_create {
2747 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2748 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2750 my $row = $self->find($cond, $attrs);
2752 $row->update($cond);
2756 return $self->create($cond);
2759 =head2 update_or_new
2763 =item Arguments: \%col_values, { key => $unique_constraint }?
2765 =item Return Value: $rowobject
2769 $resultset->update_or_new({ col => $val, ... });
2771 Like L</find_or_new> but if a row is found it is immediately updated via
2772 C<< $found_row->update (\%col_values) >>.
2776 # In your application
2777 my $cd = $schema->resultset('CD')->update_or_new(
2779 artist => 'Massive Attack',
2780 title => 'Mezzanine',
2783 { key => 'cd_artist_title' }
2786 if ($cd->in_storage) {
2787 # the cd was updated
2790 # the cd is not yet in the database, let's insert it
2794 B<Note>: Make sure to read the documentation of L</find> and understand the
2795 significance of the C<key> attribute, as its lack may skew your search, and
2796 subsequently result in spurious new objects.
2798 B<Note>: Take care when using C<update_or_new> 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<update_or_new>, even when set to C<undef>.
2804 See also L</find>, L</find_or_create> and L</find_or_new>.
2810 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2811 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2813 my $row = $self->find( $cond, $attrs );
2814 if ( defined $row ) {
2815 $row->update($cond);
2819 return $self->new_result($cond);
2826 =item Arguments: none
2828 =item Return Value: \@cache_objects | undef
2832 Gets the contents of the cache for the resultset, if the cache is set.
2834 The cache is populated either by using the L</prefetch> attribute to
2835 L</search> or by calling L</set_cache>.
2847 =item Arguments: \@cache_objects
2849 =item Return Value: \@cache_objects
2853 Sets the contents of the cache for the resultset. Expects an arrayref
2854 of objects of the same class as those produced by the resultset. Note that
2855 if the cache is set the resultset will return the cached objects rather
2856 than re-querying the database even if the cache attr is not set.
2858 The contents of the cache can also be populated by using the
2859 L</prefetch> attribute to L</search>.
2864 my ( $self, $data ) = @_;
2865 $self->throw_exception("set_cache requires an arrayref")
2866 if defined($data) && (ref $data ne 'ARRAY');
2867 $self->{all_cache} = $data;
2874 =item Arguments: none
2876 =item Return Value: undef
2880 Clears the cache for the resultset.
2885 shift->set_cache(undef);
2892 =item Arguments: none
2894 =item Return Value: true, if the resultset has been paginated
2902 return !!$self->{attrs}{page};
2909 =item Arguments: none
2911 =item Return Value: true, if the resultset has been ordered with C<order_by>.
2919 return scalar $self->result_source->storage->_extract_order_criteria($self->{attrs}{order_by});
2922 =head2 related_resultset
2926 =item Arguments: $relationship_name
2928 =item Return Value: $resultset
2932 Returns a related resultset for the supplied relationship name.
2934 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2938 sub related_resultset {
2939 my ($self, $rel) = @_;
2941 $self->{related_resultsets} ||= {};
2942 return $self->{related_resultsets}{$rel} ||= do {
2943 my $rsrc = $self->result_source;
2944 my $rel_info = $rsrc->relationship_info($rel);
2946 $self->throw_exception(
2947 "search_related: result source '" . $rsrc->source_name .
2948 "' has no such relationship $rel")
2951 my $attrs = $self->_chain_relationship($rel);
2953 my $join_count = $attrs->{seen_join}{$rel};
2955 my $alias = $self->result_source->storage
2956 ->relname_to_table_alias($rel, $join_count);
2958 # since this is search_related, and we already slid the select window inwards
2959 # (the select/as attrs were deleted in the beginning), we need to flip all
2960 # left joins to inner, so we get the expected results
2961 # read the comment on top of the actual function to see what this does
2962 $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
2965 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2966 delete @{$attrs}{qw(result_class alias)};
2970 if (my $cache = $self->get_cache) {
2971 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2972 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2977 my $rel_source = $rsrc->related_source($rel);
2981 # The reason we do this now instead of passing the alias to the
2982 # search_rs below is that if you wrap/overload resultset on the
2983 # source you need to know what alias it's -going- to have for things
2984 # to work sanely (e.g. RestrictWithObject wants to be able to add
2985 # extra query restrictions, and these may need to be $alias.)
2987 my $rel_attrs = $rel_source->resultset_attributes;
2988 local $rel_attrs->{alias} = $alias;
2990 $rel_source->resultset
2994 where => $attrs->{where},
2997 $new->set_cache($new_cache) if $new_cache;
3002 =head2 current_source_alias
3006 =item Arguments: none
3008 =item Return Value: $source_alias
3012 Returns the current table alias for the result source this resultset is built
3013 on, that will be used in the SQL query. Usually it is C<me>.
3015 Currently the source alias that refers to the result set returned by a
3016 L</search>/L</find> family method depends on how you got to the resultset: it's
3017 C<me> by default, but eg. L</search_related> aliases it to the related result
3018 source name (and keeps C<me> referring to the original result set). The long
3019 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
3020 (and make this method unnecessary).
3022 Thus it's currently necessary to use this method in predefined queries (see
3023 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
3024 source alias of the current result set:
3026 # in a result set class
3028 my ($self, $user) = @_;
3030 my $me = $self->current_source_alias;
3032 return $self->search(
3033 "$me.modified" => $user->id,
3039 sub current_source_alias {
3042 return ($self->{attrs} || {})->{alias} || 'me';
3045 =head2 as_subselect_rs
3049 =item Arguments: none
3051 =item Return Value: $resultset
3055 Act as a barrier to SQL symbols. The resultset provided will be made into a
3056 "virtual view" by including it as a subquery within the from clause. From this
3057 point on, any joined tables are inaccessible to ->search on the resultset (as if
3058 it were simply where-filtered without joins). For example:
3060 my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
3062 # 'x' now pollutes the query namespace
3064 # So the following works as expected
3065 my $ok_rs = $rs->search({'x.other' => 1});
3067 # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
3068 # def) we look for one row with contradictory terms and join in another table
3069 # (aliased 'x_2') which we never use
3070 my $broken_rs = $rs->search({'x.name' => 'def'});
3072 my $rs2 = $rs->as_subselect_rs;
3074 # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
3075 my $not_joined_rs = $rs2->search({'x.other' => 1});
3077 # works as expected: finds a 'table' row related to two x rows (abc and def)
3078 my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
3080 Another example of when one might use this would be to select a subset of
3081 columns in a group by clause:
3083 my $rs = $schema->resultset('Bar')->search(undef, {
3084 group_by => [qw{ id foo_id baz_id }],
3085 })->as_subselect_rs->search(undef, {
3086 columns => [qw{ id foo_id }]
3089 In the above example normally columns would have to be equal to the group by,
3090 but because we isolated the group by into a subselect the above works.
3094 sub as_subselect_rs {
3097 my $attrs = $self->_resolved_attrs;
3099 my $fresh_rs = (ref $self)->new (
3100 $self->result_source
3103 # these pieces will be locked in the subquery
3104 delete $fresh_rs->{cond};
3105 delete @{$fresh_rs->{attrs}}{qw/where bind/};
3107 return $fresh_rs->search( {}, {
3109 $attrs->{alias} => $self->as_query,
3110 -alias => $attrs->{alias},
3111 -rsrc => $self->result_source,
3113 alias => $attrs->{alias},
3117 # This code is called by search_related, and makes sure there
3118 # is clear separation between the joins before, during, and
3119 # after the relationship. This information is needed later
3120 # in order to properly resolve prefetch aliases (any alias
3121 # with a relation_chain_depth less than the depth of the
3122 # current prefetch is not considered)
3124 # The increments happen twice per join. An even number means a
3125 # relationship specified via a search_related, whereas an odd
3126 # number indicates a join/prefetch added via attributes
3128 # Also this code will wrap the current resultset (the one we
3129 # chain to) in a subselect IFF it contains limiting attributes
3130 sub _chain_relationship {
3131 my ($self, $rel) = @_;
3132 my $source = $self->result_source;
3133 my $attrs = { %{$self->{attrs}||{}} };
3135 # we need to take the prefetch the attrs into account before we
3136 # ->_resolve_join as otherwise they get lost - captainL
3137 my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
3139 delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
3141 my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
3144 my @force_subq_attrs = qw/offset rows group_by having/;
3147 ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
3149 $self->_has_resolved_attr (@force_subq_attrs)
3151 # Nuke the prefetch (if any) before the new $rs attrs
3152 # are resolved (prefetch is useless - we are wrapping
3153 # a subquery anyway).
3154 my $rs_copy = $self->search;
3155 $rs_copy->{attrs}{join} = $self->_merge_joinpref_attr (
3156 $rs_copy->{attrs}{join},
3157 delete $rs_copy->{attrs}{prefetch},
3162 -alias => $attrs->{alias},
3163 $attrs->{alias} => $rs_copy->as_query,
3165 delete @{$attrs}{@force_subq_attrs, qw/where bind/};
3166 $seen->{-relation_chain_depth} = 0;
3168 elsif ($attrs->{from}) { #shallow copy suffices
3169 $from = [ @{$attrs->{from}} ];
3174 -alias => $attrs->{alias},
3175 $attrs->{alias} => $source->from,
3179 my $jpath = ($seen->{-relation_chain_depth})
3180 ? $from->[-1][0]{-join_path}
3183 my @requested_joins = $source->_resolve_join(
3190 push @$from, @requested_joins;
3192 $seen->{-relation_chain_depth}++;
3194 # if $self already had a join/prefetch specified on it, the requested
3195 # $rel might very well be already included. What we do in this case
3196 # is effectively a no-op (except that we bump up the chain_depth on
3197 # the join in question so we could tell it *is* the search_related)
3200 # we consider the last one thus reverse
3201 for my $j (reverse @requested_joins) {
3202 my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
3203 if ($rel eq $last_j) {
3204 $j->[0]{-relation_chain_depth}++;
3210 unless ($already_joined) {
3211 push @$from, $source->_resolve_join(
3219 $seen->{-relation_chain_depth}++;
3221 return {%$attrs, from => $from, seen_join => $seen};
3224 # too many times we have to do $attrs = { %{$self->_resolved_attrs} }
3225 sub _resolved_attrs_copy {
3227 return { %{$self->_resolved_attrs (@_)} };
3230 sub _resolved_attrs {
3232 return $self->{_attrs} if $self->{_attrs};
3234 my $attrs = { %{ $self->{attrs} || {} } };
3235 my $source = $self->result_source;
3236 my $alias = $attrs->{alias};
3238 # one last pass of normalization
3239 $self->_normalize_selection($attrs);
3241 # default selection list
3242 $attrs->{columns} = [ $source->columns ]
3243 unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as _trailing_select/;
3245 # merge selectors together
3246 for (qw/columns select as _trailing_select/) {
3247 $attrs->{$_} = $self->_merge_attr($attrs->{$_}, $attrs->{"+$_"})
3248 if $attrs->{$_} or $attrs->{"+$_"};
3251 # disassemble columns
3253 if (my $cols = delete $attrs->{columns}) {
3254 for my $c (ref $cols eq 'ARRAY' ? @$cols : $cols) {
3255 if (ref $c eq 'HASH') {
3256 for my $as (keys %$c) {
3257 push @sel, $c->{$as};
3268 # when trying to weed off duplicates later do not go past this point -
3269 # everything added from here on is unbalanced "anyone's guess" stuff
3270 my $dedup_stop_idx = $#as;
3272 push @as, @{ ref $attrs->{as} eq 'ARRAY' ? $attrs->{as} : [ $attrs->{as} ] }
3274 push @sel, @{ ref $attrs->{select} eq 'ARRAY' ? $attrs->{select} : [ $attrs->{select} ] }
3275 if $attrs->{select};
3277 # assume all unqualified selectors to apply to the current alias (legacy stuff)
3279 $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_";
3282 # disqualify all $alias.col as-bits (collapser mandated)
3284 $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_;
3287 # de-duplicate the result (remove *identical* select/as pairs)
3288 # and also die on duplicate {as} pointing to different {select}s
3289 # not using a c-style for as the condition is prone to shrinkage
3292 while ($i <= $dedup_stop_idx) {
3293 if ($seen->{"$sel[$i] \x00\x00 $as[$i]"}++) {
3298 elsif ($seen->{$as[$i]}++) {
3299 $self->throw_exception(
3300 "inflate_result() alias '$as[$i]' specified twice with different SQL-side {select}-ors"
3308 $attrs->{select} = \@sel;
3309 $attrs->{as} = \@as;
3311 $attrs->{from} ||= [{
3313 -alias => $self->{attrs}{alias},
3314 $self->{attrs}{alias} => $source->from,
3317 if ( $attrs->{join} || $attrs->{prefetch} ) {
3319 $self->throw_exception ('join/prefetch can not be used with a custom {from}')
3320 if ref $attrs->{from} ne 'ARRAY';
3322 my $join = (delete $attrs->{join}) || {};
3324 if ( defined $attrs->{prefetch} ) {
3325 $join = $self->_merge_joinpref_attr( $join, $attrs->{prefetch} );
3328 $attrs->{from} = # have to copy here to avoid corrupting the original
3330 @{ $attrs->{from} },
3331 $source->_resolve_join(
3334 { %{ $attrs->{seen_join} || {} } },
3335 ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
3336 ? $attrs->{from}[-1][0]{-join_path}
3343 if ( defined $attrs->{order_by} ) {
3344 $attrs->{order_by} = (
3345 ref( $attrs->{order_by} ) eq 'ARRAY'
3346 ? [ @{ $attrs->{order_by} } ]
3347 : [ $attrs->{order_by} || () ]
3351 if ($attrs->{group_by} and ref $attrs->{group_by} ne 'ARRAY') {
3352 $attrs->{group_by} = [ $attrs->{group_by} ];
3355 # generate the distinct induced group_by early, as prefetch will be carried via a
3356 # subquery (since a group_by is present)
3357 if (delete $attrs->{distinct}) {
3358 if ($attrs->{group_by}) {
3359 carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
3362 # distinct affects only the main selection part, not what prefetch may
3363 # add below. However trailing is not yet a part of the selection as
3364 # prefetch must insert before it
3365 $attrs->{group_by} = $source->storage->_group_over_selection (
3367 [ @{$attrs->{select}||[]}, @{$attrs->{_trailing_select}||[]} ],
3373 $attrs->{collapse} ||= {};
3374 if ($attrs->{prefetch}) {
3375 my $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} );
3377 my $prefetch_ordering = [];
3379 # this is a separate structure (we don't look in {from} directly)
3380 # as the resolver needs to shift things off the lists to work
3381 # properly (identical-prefetches on different branches)
3383 if (ref $attrs->{from} eq 'ARRAY') {
3385 my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
3387 for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
3388 next unless $j->[0]{-alias};
3389 next unless $j->[0]{-join_path};
3390 next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
3392 my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
3395 $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
3396 push @{$p->{-join_aliases} }, $j->[0]{-alias};
3401 $source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
3403 # we need to somehow mark which columns came from prefetch
3405 my $sel_end = $#{$attrs->{select}};
3406 $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
3409 push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
3410 push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
3412 push( @{$attrs->{order_by}}, @$prefetch_ordering );
3413 $attrs->{_collapse_order_by} = \@$prefetch_ordering;
3417 push @{ $attrs->{select} }, @{$attrs->{_trailing_select}}
3418 if $attrs->{_trailing_select};
3420 # if both page and offset are specified, produce a combined offset
3421 # even though it doesn't make much sense, this is what pre 081xx has
3423 if (my $page = delete $attrs->{page}) {
3425 ($attrs->{rows} * ($page - 1))
3427 ($attrs->{offset} || 0)
3431 return $self->{_attrs} = $attrs;
3435 my ($self, $attr) = @_;
3437 if (ref $attr eq 'HASH') {
3438 return $self->_rollout_hash($attr);
3439 } elsif (ref $attr eq 'ARRAY') {
3440 return $self->_rollout_array($attr);
3446 sub _rollout_array {
3447 my ($self, $attr) = @_;
3450 foreach my $element (@{$attr}) {
3451 if (ref $element eq 'HASH') {
3452 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
3453 } elsif (ref $element eq 'ARRAY') {
3454 # XXX - should probably recurse here
3455 push( @rolled_array, @{$self->_rollout_array($element)} );
3457 push( @rolled_array, $element );
3460 return \@rolled_array;
3464 my ($self, $attr) = @_;
3467 foreach my $key (keys %{$attr}) {
3468 push( @rolled_array, { $key => $attr->{$key} } );
3470 return \@rolled_array;
3473 sub _calculate_score {
3474 my ($self, $a, $b) = @_;
3476 if (defined $a xor defined $b) {
3479 elsif (not defined $a) {
3483 if (ref $b eq 'HASH') {
3484 my ($b_key) = keys %{$b};
3485 if (ref $a eq 'HASH') {
3486 my ($a_key) = keys %{$a};
3487 if ($a_key eq $b_key) {
3488 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
3493 return ($a eq $b_key) ? 1 : 0;
3496 if (ref $a eq 'HASH') {
3497 my ($a_key) = keys %{$a};
3498 return ($b eq $a_key) ? 1 : 0;
3500 return ($b eq $a) ? 1 : 0;
3505 sub _merge_joinpref_attr {
3506 my ($self, $orig, $import) = @_;
3508 return $import unless defined($orig);
3509 return $orig unless defined($import);
3511 $orig = $self->_rollout_attr($orig);
3512 $import = $self->_rollout_attr($import);
3515 foreach my $import_element ( @{$import} ) {
3516 # find best candidate from $orig to merge $b_element into
3517 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
3518 foreach my $orig_element ( @{$orig} ) {
3519 my $score = $self->_calculate_score( $orig_element, $import_element );
3520 if ($score > $best_candidate->{score}) {
3521 $best_candidate->{position} = $position;
3522 $best_candidate->{score} = $score;
3526 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
3528 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
3529 push( @{$orig}, $import_element );
3531 my $orig_best = $orig->[$best_candidate->{position}];
3532 # merge orig_best and b_element together and replace original with merged
3533 if (ref $orig_best ne 'HASH') {
3534 $orig->[$best_candidate->{position}] = $import_element;
3535 } elsif (ref $import_element eq 'HASH') {
3536 my ($key) = keys %{$orig_best};
3537 $orig->[$best_candidate->{position}] = { $key => $self->_merge_joinpref_attr($orig_best->{$key}, $import_element->{$key}) };
3540 $seen_keys->{$import_key} = 1; # don't merge the same key twice
3551 require Hash::Merge;
3552 my $hm = Hash::Merge->new;
3554 $hm->specify_behavior({
3557 my ($defl, $defr) = map { defined $_ } (@_[0,1]);
3559 if ($defl xor $defr) {
3560 return [ $defl ? $_[0] : $_[1] ];
3565 elsif (__HM_DEDUP and $_[0] eq $_[1]) {
3569 return [$_[0], $_[1]];
3573 return $_[1] if !defined $_[0];
3574 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3575 return [$_[0], @{$_[1]}]
3578 return [] if !defined $_[0] and !keys %{$_[1]};
3579 return [ $_[1] ] if !defined $_[0];
3580 return [ $_[0] ] if !keys %{$_[1]};
3581 return [$_[0], $_[1]]
3586 return $_[0] if !defined $_[1];
3587 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3588 return [@{$_[0]}, $_[1]]
3591 my @ret = @{$_[0]} or return $_[1];
3592 return [ @ret, @{$_[1]} ] unless __HM_DEDUP;
3593 my %idx = map { $_ => 1 } @ret;
3594 push @ret, grep { ! defined $idx{$_} } (@{$_[1]});
3598 return [ $_[1] ] if ! @{$_[0]};
3599 return $_[0] if !keys %{$_[1]};
3600 return $_[0] if __HM_DEDUP and List::Util::first { $_ eq $_[1] } @{$_[0]};
3601 return [ @{$_[0]}, $_[1] ];
3606 return [] if !keys %{$_[0]} and !defined $_[1];
3607 return [ $_[0] ] if !defined $_[1];
3608 return [ $_[1] ] if !keys %{$_[0]};
3609 return [$_[0], $_[1]]
3612 return [] if !keys %{$_[0]} and !@{$_[1]};
3613 return [ $_[0] ] if !@{$_[1]};
3614 return $_[1] if !keys %{$_[0]};
3615 return $_[1] if __HM_DEDUP and List::Util::first { $_ eq $_[0] } @{$_[1]};
3616 return [ $_[0], @{$_[1]} ];
3619 return [] if !keys %{$_[0]} and !keys %{$_[1]};
3620 return [ $_[0] ] if !keys %{$_[1]};
3621 return [ $_[1] ] if !keys %{$_[0]};
3622 return [ $_[0] ] if $_[0] eq $_[1];
3623 return [ $_[0], $_[1] ];
3626 } => 'DBIC_RS_ATTR_MERGER');
3630 return $hm->merge ($_[1], $_[2]);
3634 sub STORABLE_freeze {
3635 my ($self, $cloning) = @_;
3636 my $to_serialize = { %$self };
3638 # A cursor in progress can't be serialized (and would make little sense anyway)
3639 delete $to_serialize->{cursor};
3641 Storable::nfreeze($to_serialize);
3644 # need this hook for symmetry
3646 my ($self, $cloning, $serialized) = @_;
3648 %$self = %{ Storable::thaw($serialized) };
3654 =head2 throw_exception
3656 See L<DBIx::Class::Schema/throw_exception> for details.
3660 sub throw_exception {
3663 if (ref $self and my $rsrc = $self->result_source) {
3664 $rsrc->throw_exception(@_)
3667 DBIx::Class::Exception->throw(@_);
3671 # XXX: FIXME: Attributes docs need clearing up
3675 Attributes are used to refine a ResultSet in various ways when
3676 searching for data. They can be passed to any method which takes an
3677 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
3680 These are in no particular order:
3686 =item Value: ( $order_by | \@order_by | \%order_by )
3690 Which column(s) to order the results by.
3692 [The full list of suitable values is documented in
3693 L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
3696 If a single column name, or an arrayref of names is supplied, the
3697 argument is passed through directly to SQL. The hashref syntax allows
3698 for connection-agnostic specification of ordering direction:
3700 For descending order:
3702 order_by => { -desc => [qw/col1 col2 col3/] }
3704 For explicit ascending order:
3706 order_by => { -asc => 'col' }
3708 The old scalarref syntax (i.e. order_by => \'year DESC') is still
3709 supported, although you are strongly encouraged to use the hashref
3710 syntax as outlined above.
3716 =item Value: \@columns
3720 Shortcut to request a particular set of columns to be retrieved. Each
3721 column spec may be a string (a table column name), or a hash (in which
3722 case the key is the C<as> value, and the value is used as the C<select>
3723 expression). Adds C<me.> onto the start of any column without a C<.> in
3724 it and sets C<select> from that, then auto-populates C<as> from
3725 C<select> as normal. (You may also use the C<cols> attribute, as in
3726 earlier versions of DBIC.)
3728 Essentially C<columns> does the same as L</select> and L</as>.
3730 columns => [ 'foo', { bar => 'baz' } ]
3734 select => [qw/foo baz/],
3741 =item Value: \@columns
3745 Indicates additional columns to be selected from storage. Works the same
3746 as L</columns> but adds columns to the selection. (You may also use the
3747 C<include_columns> attribute, as in earlier versions of DBIC). For
3750 $schema->resultset('CD')->search(undef, {
3751 '+columns' => ['artist.name'],
3755 would return all CDs and include a 'name' column to the information
3756 passed to object inflation. Note that the 'artist' is the name of the
3757 column (or relationship) accessor, and 'name' is the name of the column
3758 accessor in the related table.
3760 B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
3761 Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
3762 unary plus operator before it.
3764 =head2 include_columns
3768 =item Value: \@columns
3772 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
3778 =item Value: \@select_columns
3782 Indicates which columns should be selected from the storage. You can use
3783 column names, or in the case of RDBMS back ends, function or stored procedure
3786 $rs = $schema->resultset('Employee')->search(undef, {
3789 { count => 'employeeid' },
3790 { max => { length => 'name' }, -as => 'longest_name' }
3795 SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
3797 B<NOTE:> You will almost always need a corresponding L</as> attribute when you
3798 use L</select>, to instruct DBIx::Class how to store the result of the column.
3799 Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
3800 identifier aliasing. You can however alias a function, so you can use it in
3801 e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
3802 attribute> supplied as shown in the example above.
3804 B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
3805 Not doing so causes Perl to incorrectly interpret them as a bareword with a
3806 unary plus operator before it.
3812 Indicates additional columns to be selected from storage. Works the same as
3813 L</select> but adds columns to the default selection, instead of specifying
3822 Indicates additional column names for those added via L</+select>. See L</as>.
3830 =item Value: \@inflation_names
3834 Indicates column names for object inflation. That is L</as> indicates the
3835 slot name in which the column value will be stored within the
3836 L<Row|DBIx::Class::Row> object. The value will then be accessible via this
3837 identifier by the C<get_column> method (or via the object accessor B<if one
3838 with the same name already exists>) as shown below. The L</as> attribute has
3839 B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
3841 $rs = $schema->resultset('Employee')->search(undef, {
3844 { count => 'employeeid' },
3845 { max => { length => 'name' }, -as => 'longest_name' }
3854 If the object against which the search is performed already has an accessor
3855 matching a column name specified in C<as>, the value can be retrieved using
3856 the accessor as normal:
3858 my $name = $employee->name();
3860 If on the other hand an accessor does not exist in the object, you need to
3861 use C<get_column> instead:
3863 my $employee_count = $employee->get_column('employee_count');
3865 You can create your own accessors if required - see
3866 L<DBIx::Class::Manual::Cookbook> for details.
3872 =item Value: ($rel_name | \@rel_names | \%rel_names)
3876 Contains a list of relationships that should be joined for this query. For
3879 # Get CDs by Nine Inch Nails
3880 my $rs = $schema->resultset('CD')->search(
3881 { 'artist.name' => 'Nine Inch Nails' },
3882 { join => 'artist' }
3885 Can also contain a hash reference to refer to the other relation's relations.
3888 package MyApp::Schema::Track;
3889 use base qw/DBIx::Class/;
3890 __PACKAGE__->table('track');
3891 __PACKAGE__->add_columns(qw/trackid cd position title/);
3892 __PACKAGE__->set_primary_key('trackid');
3893 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
3896 # In your application
3897 my $rs = $schema->resultset('Artist')->search(
3898 { 'track.title' => 'Teardrop' },
3900 join => { cd => 'track' },
3901 order_by => 'artist.name',
3905 You need to use the relationship (not the table) name in conditions,
3906 because they are aliased as such. The current table is aliased as "me", so
3907 you need to use me.column_name in order to avoid ambiguity. For example:
3909 # Get CDs from 1984 with a 'Foo' track
3910 my $rs = $schema->resultset('CD')->search(
3913 'tracks.name' => 'Foo'
3915 { join => 'tracks' }
3918 If the same join is supplied twice, it will be aliased to <rel>_2 (and
3919 similarly for a third time). For e.g.
3921 my $rs = $schema->resultset('Artist')->search({
3922 'cds.title' => 'Down to Earth',
3923 'cds_2.title' => 'Popular',
3925 join => [ qw/cds cds/ ],
3928 will return a set of all artists that have both a cd with title 'Down
3929 to Earth' and a cd with title 'Popular'.
3931 If you want to fetch related objects from other tables as well, see C<prefetch>
3934 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
3940 =item Value: ($rel_name | \@rel_names | \%rel_names)
3944 Contains one or more relationships that should be fetched along with
3945 the main query (when they are accessed afterwards the data will
3946 already be available, without extra queries to the database). This is
3947 useful for when you know you will need the related objects, because it
3948 saves at least one query:
3950 my $rs = $schema->resultset('Tag')->search(
3959 The initial search results in SQL like the following:
3961 SELECT tag.*, cd.*, artist.* FROM tag
3962 JOIN cd ON tag.cd = cd.cdid
3963 JOIN artist ON cd.artist = artist.artistid
3965 L<DBIx::Class> has no need to go back to the database when we access the
3966 C<cd> or C<artist> relationships, which saves us two SQL statements in this
3969 Simple prefetches will be joined automatically, so there is no need
3970 for a C<join> attribute in the above search.
3972 L</prefetch> can be used with the any of the relationship types and
3973 multiple prefetches can be specified together. Below is a more complex
3974 example that prefetches a CD's artist, its liner notes (if present),
3975 the cover image, the tracks on that cd, and the guests on those
3979 My::Schema::CD->belongs_to( artist => 'My::Schema::Artist' );
3980 My::Schema::CD->might_have( liner_note => 'My::Schema::LinerNotes' );
3981 My::Schema::CD->has_one( cover_image => 'My::Schema::Artwork' );
3982 My::Schema::CD->has_many( tracks => 'My::Schema::Track' );
3984 My::Schema::Artist->belongs_to( record_label => 'My::Schema::RecordLabel' );
3986 My::Schema::Track->has_many( guests => 'My::Schema::Guest' );
3989 my $rs = $schema->resultset('CD')->search(
3993 { artist => 'record_label'}, # belongs_to => belongs_to
3994 'liner_note', # might_have
3995 'cover_image', # has_one
3996 { tracks => 'guests' }, # has_many => has_many
4001 This will produce SQL like the following:
4003 SELECT cd.*, artist.*, record_label.*, liner_note.*, cover_image.*,
4007 ON artist.artistid = me.artistid
4008 JOIN record_label record_label
4009 ON record_label.labelid = artist.labelid
4010 LEFT JOIN track tracks
4011 ON tracks.cdid = me.cdid
4012 LEFT JOIN guest guests
4013 ON guests.trackid = track.trackid
4014 LEFT JOIN liner_notes liner_note
4015 ON liner_note.cdid = me.cdid
4016 JOIN cd_artwork cover_image
4017 ON cover_image.cdid = me.cdid
4020 Now the C<artist>, C<record_label>, C<liner_note>, C<cover_image>,
4021 C<tracks>, and C<guests> of the CD will all be available through the
4022 relationship accessors without the need for additional queries to the
4025 However, there is one caveat to be observed: it can be dangerous to
4026 prefetch more than one L<has_many|DBIx::Class::Relationship/has_many>
4027 relationship on a given level. e.g.:
4029 my $rs = $schema->resultset('CD')->search(
4033 'tracks', # has_many
4034 { cd_to_producer => 'producer' }, # has_many => belongs_to (i.e. m2m)
4039 In fact, C<DBIx::Class> will emit the following warning:
4041 Prefetching multiple has_many rels tracks and cd_to_producer at top
4042 level will explode the number of row objects retrievable via ->next
4043 or ->all. Use at your own risk.
4045 The collapser currently can't identify duplicate tuples for multiple
4046 L<has_many|DBIx::Class::Relationship/has_many> relationships and as a
4047 result the second L<has_many|DBIx::Class::Relationship/has_many>
4048 relation could contain redundant objects.
4050 =head3 Using L</prefetch> with L</join>
4052 L</prefetch> implies a L</join> with the equivalent argument, and is
4053 properly merged with any existing L</join> specification. So the
4056 my $rs = $schema->resultset('CD')->search(
4057 {'record_label.name' => 'Music Product Ltd.'},
4059 join => {artist => 'record_label'},
4060 prefetch => 'artist',
4064 ... will work, searching on the record label's name, but only
4065 prefetching the C<artist>.
4067 =head3 Using L</prefetch> with L</select> / L</+select> / L</as> / L</+as>
4069 L</prefetch> implies a L</+select>/L</+as> with the fields of the
4070 prefetched relations. So given:
4072 my $rs = $schema->resultset('CD')->search(
4075 select => ['cd.title'],
4077 prefetch => 'artist',
4081 The L</select> becomes: C<'cd.title', 'artist.*'> and the L</as>
4082 becomes: C<'cd_title', 'artist.*'>.
4086 Prefetch does a lot of deep magic. As such, it may not behave exactly
4087 as you might expect.
4093 Prefetch uses the L</cache> to populate the prefetched relationships. This
4094 may or may not be what you want.
4098 If you specify a condition on a prefetched relationship, ONLY those
4099 rows that match the prefetched condition will be fetched into that relationship.
4100 This means that adding prefetch to a search() B<may alter> what is returned by
4101 traversing a relationship. So, if you have C<< Artist->has_many(CDs) >> and you do
4103 my $artist_rs = $schema->resultset('Artist')->search({
4109 my $count = $artist_rs->first->cds->count;
4111 my $artist_rs_prefetch = $artist_rs->search( {}, { prefetch => 'cds' } );
4113 my $prefetch_count = $artist_rs_prefetch->first->cds->count;
4115 cmp_ok( $count, '==', $prefetch_count, "Counts should be the same" );
4117 that cmp_ok() may or may not pass depending on the datasets involved. This
4118 behavior may or may not survive the 0.09 transition.
4130 Makes the resultset paged and specifies the page to retrieve. Effectively
4131 identical to creating a non-pages resultset and then calling ->page($page)
4134 If L</rows> attribute is not specified it defaults to 10 rows per page.
4136 When you have a paged resultset, L</count> will only return the number
4137 of rows in the page. To get the total, use the L</pager> and call
4138 C<total_entries> on it.
4148 Specifies the maximum number of rows for direct retrieval or the number of
4149 rows per page if the page attribute or method is used.
4155 =item Value: $offset
4159 Specifies the (zero-based) row number for the first row to be returned, or the
4160 of the first row of the first page if paging is used.
4166 =item Value: \@columns
4170 A arrayref of columns to group by. Can include columns of joined tables.
4172 group_by => [qw/ column1 column2 ... /]
4178 =item Value: $condition
4182 HAVING is a select statement attribute that is applied between GROUP BY and
4183 ORDER BY. It is applied to the after the grouping calculations have been
4186 having => { 'count_employee' => { '>=', 100 } }
4188 or with an in-place function in which case literal SQL is required:
4190 having => \[ 'count(employee) >= ?', [ count => 100 ] ]
4196 =item Value: (0 | 1)
4200 Set to 1 to group by all columns. If the resultset already has a group_by
4201 attribute, this setting is ignored and an appropriate warning is issued.
4207 Adds to the WHERE clause.
4209 # only return rows WHERE deleted IS NULL for all searches
4210 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
4212 Can be overridden by passing C<< { where => undef } >> as an attribute
4219 Set to 1 to cache search results. This prevents extra SQL queries if you
4220 revisit rows in your ResultSet:
4222 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
4224 while( my $artist = $resultset->next ) {
4228 $rs->first; # without cache, this would issue a query
4230 By default, searches are not cached.
4232 For more examples of using these attributes, see
4233 L<DBIx::Class::Manual::Cookbook>.
4239 =item Value: ( 'update' | 'shared' )
4243 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT