1 package DBIx::Class::ResultSet;
9 use Carp::Clan qw/^DBIx::Class/;
12 use DBIx::Class::ResultSetColumn;
13 use DBIx::Class::ResultSourceHandle;
14 use base qw/DBIx::Class/;
16 __PACKAGE__->mk_group_accessors('simple' => qw/result_class _source_handle/);
20 DBIx::Class::ResultSet - Responsible for fetching and creating resultset.
24 my $rs = $schema->resultset('User')->search(registered => 1);
25 my @rows = $schema->resultset('CD')->search(year => 2005);
29 The resultset is also known as an iterator. It is responsible for handling
30 queries that may return an arbitrary number of rows, e.g. via L</search>
31 or a C<has_many> relationship.
33 In the examples below, the following table classes are used:
35 package MyApp::Schema::Artist;
36 use base qw/DBIx::Class/;
37 __PACKAGE__->load_components(qw/Core/);
38 __PACKAGE__->table('artist');
39 __PACKAGE__->add_columns(qw/artistid name/);
40 __PACKAGE__->set_primary_key('artistid');
41 __PACKAGE__->has_many(cds => 'MyApp::Schema::CD');
44 package MyApp::Schema::CD;
45 use base qw/DBIx::Class/;
46 __PACKAGE__->load_components(qw/Core/);
47 __PACKAGE__->table('cd');
48 __PACKAGE__->add_columns(qw/cdid artist title year/);
49 __PACKAGE__->set_primary_key('cdid');
50 __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Artist');
59 =item Arguments: $source, \%$attrs
61 =item Return Value: $rs
65 The resultset constructor. Takes a source object (usually a
66 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
67 L</ATTRIBUTES> below). Does not perform any queries -- these are
68 executed as needed by the other methods.
70 Generally you won't need to construct a resultset manually. You'll
71 automatically get one from e.g. a L</search> called in scalar context:
73 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
75 IMPORTANT: If called on an object, proxies to new_result instead so
77 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
79 will return a CD object, not a ResultSet.
85 return $class->new_result(@_) if ref $class;
87 my ($source, $attrs) = @_;
88 $source = $source->handle
89 unless $source->isa('DBIx::Class::ResultSourceHandle');
90 $attrs = { %{$attrs||{}} };
93 $attrs->{rows} ||= 10;
94 $attrs->{offset} ||= 0;
95 $attrs->{offset} += ($attrs->{rows} * ($attrs->{page} - 1));
98 $attrs->{alias} ||= 'me';
101 _source_handle => $source,
102 result_class => $attrs->{result_class} || $source->resolve->result_class,
103 cond => $attrs->{where},
118 =item Arguments: $cond, \%attrs?
120 =item Return Value: $resultset (scalar context), @row_objs (list context)
124 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
125 my $new_rs = $cd_rs->search({ year => 2005 });
127 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
128 # year = 2005 OR year = 2004
130 If you need to pass in additional attributes but no additional condition,
131 call it as C<search(undef, \%attrs)>.
133 # "SELECT name, artistid FROM $artist_table"
134 my @all_artists = $schema->resultset('Artist')->search(undef, {
135 columns => [qw/name artistid/],
138 For a list of attributes that can be passed to C<search>, see
139 L</ATTRIBUTES>. For more examples of using this function, see
140 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
141 documentation for the first argument, see L<SQL::Abstract>.
147 my $rs = $self->search_rs( @_ );
148 return (wantarray ? $rs->all : $rs);
155 =item Arguments: $cond, \%attrs?
157 =item Return Value: $resultset
161 This method does the same exact thing as search() except it will
162 always return a resultset, even in list context.
171 unless (@_) { # no search, effectively just a clone
172 $rows = $self->get_cache;
176 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
177 my $our_attrs = { %{$self->{attrs}} };
178 my $having = delete $our_attrs->{having};
179 my $where = delete $our_attrs->{where};
181 my $new_attrs = { %{$our_attrs}, %{$attrs} };
183 # merge new attrs into inherited
184 foreach my $key (qw/join prefetch/) {
185 next unless exists $attrs->{$key};
186 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
191 (@_ == 1 || ref $_[0] eq "HASH")
193 (ref $_[0] eq 'HASH')
195 (keys %{ $_[0] } > 0)
203 ? $self->throw_exception("Odd number of arguments to search")
210 if (defined $where) {
211 $new_attrs->{where} = (
212 defined $new_attrs->{where}
215 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
216 } $where, $new_attrs->{where}
223 $new_attrs->{where} = (
224 defined $new_attrs->{where}
227 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
228 } $cond, $new_attrs->{where}
234 if (defined $having) {
235 $new_attrs->{having} = (
236 defined $new_attrs->{having}
239 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
240 } $having, $new_attrs->{having}
246 my $rs = (ref $self)->new($self->result_source, $new_attrs);
248 $rs->set_cache($rows);
253 =head2 search_literal
257 =item Arguments: $sql_fragment, @bind_values
259 =item Return Value: $resultset (scalar context), @row_objs (list context)
263 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
264 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
266 Pass a literal chunk of SQL to be added to the conditional part of the
272 my ($self, $cond, @vals) = @_;
273 my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
274 $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ];
275 return $self->search(\$cond, $attrs);
282 =item Arguments: @values | \%cols, \%attrs?
284 =item Return Value: $row_object
288 Finds a row based on its primary key or unique constraint. For example, to find
289 a row by its primary key:
291 my $cd = $schema->resultset('CD')->find(5);
293 You can also find a row by a specific unique constraint using the C<key>
294 attribute. For example:
296 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
297 key => 'cd_artist_title'
300 Additionally, you can specify the columns explicitly by name:
302 my $cd = $schema->resultset('CD')->find(
304 artist => 'Massive Attack',
305 title => 'Mezzanine',
307 { key => 'cd_artist_title' }
310 If the C<key> is specified as C<primary>, it searches only on the primary key.
312 If no C<key> is specified, it searches on all unique constraints defined on the
313 source, including the primary key.
315 If your table does not have a primary key, you B<must> provide a value for the
316 C<key> attribute matching one of the unique constraints on the source.
318 See also L</find_or_create> and L</update_or_create>. For information on how to
319 declare unique constraints, see
320 L<DBIx::Class::ResultSource/add_unique_constraint>.
326 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
328 # Default to the primary key, but allow a specific key
329 my @cols = exists $attrs->{key}
330 ? $self->result_source->unique_constraint_columns($attrs->{key})
331 : $self->result_source->primary_columns;
332 $self->throw_exception(
333 "Can't find unless a primary key is defined or unique constraint is specified"
336 # Parse out a hashref from input
338 if (ref $_[0] eq 'HASH') {
339 $input_query = { %{$_[0]} };
341 elsif (@_ == @cols) {
343 @{$input_query}{@cols} = @_;
346 # Compatibility: Allow e.g. find(id => $value)
347 carp "Find by key => value deprecated; please use a hashref instead";
351 my (%related, $info);
353 KEY: foreach my $key (keys %$input_query) {
354 if (ref($input_query->{$key})
355 && ($info = $self->result_source->relationship_info($key))) {
356 my $val = delete $input_query->{$key};
357 next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
358 my $rel_q = $self->result_source->resolve_condition(
359 $info->{cond}, $val, $key
361 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
362 @related{keys %$rel_q} = values %$rel_q;
365 if (my @keys = keys %related) {
366 @{$input_query}{@keys} = values %related;
369 my @unique_queries = $self->_unique_queries($input_query, $attrs);
371 # Build the final query: Default to the disjunction of the unique queries,
372 # but allow the input query in case the ResultSet defines the query or the
373 # user is abusing find
374 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
375 my $query = @unique_queries
376 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
377 : $self->_add_alias($input_query, $alias);
381 my $rs = $self->search($query, $attrs);
382 return keys %{$rs->_resolved_attrs->{collapse}} ? $rs->next : $rs->single;
385 return keys %{$self->_resolved_attrs->{collapse}}
386 ? $self->search($query)->next
387 : $self->single($query);
393 # Add the specified alias to the specified query hash. A copy is made so the
394 # original query is not modified.
397 my ($self, $query, $alias) = @_;
399 my %aliased = %$query;
400 foreach my $col (grep { ! m/\./ } keys %aliased) {
401 $aliased{"$alias.$col"} = delete $aliased{$col};
409 # Build a list of queries which satisfy unique constraints.
411 sub _unique_queries {
412 my ($self, $query, $attrs) = @_;
414 my @constraint_names = exists $attrs->{key}
416 : $self->result_source->unique_constraint_names;
418 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
419 my $num_where = scalar keys %$where;
422 foreach my $name (@constraint_names) {
423 my @unique_cols = $self->result_source->unique_constraint_columns($name);
424 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
426 my $num_cols = scalar @unique_cols;
427 my $num_query = scalar keys %$unique_query;
429 my $total = $num_query + $num_where;
430 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
431 # The query is either unique on its own or is unique in combination with
432 # the existing where clause
433 push @unique_queries, $unique_query;
437 return @unique_queries;
440 # _build_unique_query
442 # Constrain the specified query hash based on the specified column names.
444 sub _build_unique_query {
445 my ($self, $query, $unique_cols) = @_;
448 map { $_ => $query->{$_} }
449 grep { exists $query->{$_} }
454 =head2 search_related
458 =item Arguments: $rel, $cond, \%attrs?
460 =item Return Value: $new_resultset
464 $new_rs = $cd_rs->search_related('artist', {
468 Searches the specified relationship, optionally specifying a condition and
469 attributes for matching records. See L</ATTRIBUTES> for more information.
474 return shift->related_resultset(shift)->search(@_);
481 =item Arguments: none
483 =item Return Value: $cursor
487 Returns a storage-driven cursor to the given resultset. See
488 L<DBIx::Class::Cursor> for more information.
495 my $attrs = { %{$self->_resolved_attrs} };
496 return $self->{cursor}
497 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
498 $attrs->{where},$attrs);
505 =item Arguments: $cond?
507 =item Return Value: $row_object?
511 my $cd = $schema->resultset('CD')->single({ year => 2001 });
513 Inflates the first result without creating a cursor if the resultset has
514 any records in it; if not returns nothing. Used by L</find> as an optimisation.
516 Can optionally take an additional condition *only* - this is a fast-code-path
517 method; if you need to add extra joins or similar call ->search and then
518 ->single without a condition on the $rs returned from that.
523 my ($self, $where) = @_;
524 my $attrs = { %{$self->_resolved_attrs} };
526 if (defined $attrs->{where}) {
529 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
530 $where, delete $attrs->{where} ]
533 $attrs->{where} = $where;
537 # XXX: Disabled since it doesn't infer uniqueness in all cases
538 # unless ($self->_is_unique_query($attrs->{where})) {
539 # carp "Query not guaranteed to return a single row"
540 # . "; please declare your unique constraints or use search instead";
543 my @data = $self->result_source->storage->select_single(
544 $attrs->{from}, $attrs->{select},
545 $attrs->{where}, $attrs
548 return (@data ? ($self->_construct_object(@data))[0] : ());
553 # Try to determine if the specified query is guaranteed to be unique, based on
554 # the declared unique constraints.
556 sub _is_unique_query {
557 my ($self, $query) = @_;
559 my $collapsed = $self->_collapse_query($query);
560 my $alias = $self->{attrs}{alias};
562 foreach my $name ($self->result_source->unique_constraint_names) {
563 my @unique_cols = map {
565 } $self->result_source->unique_constraint_columns($name);
567 # Count the values for each unique column
568 my %seen = map { $_ => 0 } @unique_cols;
570 foreach my $key (keys %$collapsed) {
571 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
572 next unless exists $seen{$aliased}; # Additional constraints are okay
573 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
576 # If we get 0 or more than 1 value for a column, it's not necessarily unique
577 return 1 unless grep { $_ != 1 } values %seen;
585 # Recursively collapse the query, accumulating values for each column.
587 sub _collapse_query {
588 my ($self, $query, $collapsed) = @_;
592 if (ref $query eq 'ARRAY') {
593 foreach my $subquery (@$query) {
594 next unless ref $subquery; # -or
595 # warn "ARRAY: " . Dumper $subquery;
596 $collapsed = $self->_collapse_query($subquery, $collapsed);
599 elsif (ref $query eq 'HASH') {
600 if (keys %$query and (keys %$query)[0] eq '-and') {
601 foreach my $subquery (@{$query->{-and}}) {
602 # warn "HASH: " . Dumper $subquery;
603 $collapsed = $self->_collapse_query($subquery, $collapsed);
607 # warn "LEAF: " . Dumper $query;
608 foreach my $col (keys %$query) {
609 my $value = $query->{$col};
610 $collapsed->{$col}{$value}++;
622 =item Arguments: $cond?
624 =item Return Value: $resultsetcolumn
628 my $max_length = $rs->get_column('length')->max;
630 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
635 my ($self, $column) = @_;
636 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
644 =item Arguments: $cond, \%attrs?
646 =item Return Value: $resultset (scalar context), @row_objs (list context)
650 # WHERE title LIKE '%blue%'
651 $cd_rs = $rs->search_like({ title => '%blue%'});
653 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
654 that this is simply a convenience method. You most likely want to use
655 L</search> with specific operators.
657 For more information, see L<DBIx::Class::Manual::Cookbook>.
663 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
664 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
665 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
666 return $class->search($query, { %$attrs });
673 =item Arguments: $first, $last
675 =item Return Value: $resultset (scalar context), @row_objs (list context)
679 Returns a resultset or object list representing a subset of elements from the
680 resultset slice is called on. Indexes are from 0, i.e., to get the first
683 my ($one, $two, $three) = $rs->slice(0, 2);
688 my ($self, $min, $max) = @_;
689 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
690 $attrs->{offset} = $self->{attrs}{offset} || 0;
691 $attrs->{offset} += $min;
692 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
693 return $self->search(undef(), $attrs);
694 #my $slice = (ref $self)->new($self->result_source, $attrs);
695 #return (wantarray ? $slice->all : $slice);
702 =item Arguments: none
704 =item Return Value: $result?
708 Returns the next element in the resultset (C<undef> is there is none).
710 Can be used to efficiently iterate over records in the resultset:
712 my $rs = $schema->resultset('CD')->search;
713 while (my $cd = $rs->next) {
717 Note that you need to store the resultset object, and call C<next> on it.
718 Calling C<< resultset('Table')->next >> repeatedly will always return the
719 first record from the resultset.
725 if (my $cache = $self->get_cache) {
726 $self->{all_cache_position} ||= 0;
727 return $cache->[$self->{all_cache_position}++];
729 if ($self->{attrs}{cache}) {
730 $self->{all_cache_position} = 1;
731 return ($self->all)[0];
733 if ($self->{stashed_objects}) {
734 my $obj = shift(@{$self->{stashed_objects}});
735 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
739 exists $self->{stashed_row}
740 ? @{delete $self->{stashed_row}}
741 : $self->cursor->next
743 return unless (@row);
744 my ($row, @more) = $self->_construct_object(@row);
745 $self->{stashed_objects} = \@more if @more;
749 sub _construct_object {
750 my ($self, @row) = @_;
751 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
752 my @new = $self->result_class->inflate_result($self->result_source, @$info);
753 @new = $self->{_attrs}{record_filter}->(@new)
754 if exists $self->{_attrs}{record_filter};
758 sub _collapse_result {
759 my ($self, $as_proto, $row) = @_;
763 # 'foo' => [ undef, 'foo' ]
764 # 'foo.bar' => [ 'foo', 'bar' ]
765 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
767 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
769 my %collapse = %{$self->{_attrs}{collapse}||{}};
773 # if we're doing collapsing (has_many prefetch) we need to grab records
774 # until the PK changes, so fill @pri_index. if not, we leave it empty so
775 # we know we don't have to bother.
777 # the reason for not using the collapse stuff directly is because if you
778 # had for e.g. two artists in a row with no cds, the collapse info for
779 # both would be NULL (undef) so you'd lose the second artist
781 # store just the index so we can check the array positions from the row
782 # without having to contruct the full hash
784 if (keys %collapse) {
785 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
786 foreach my $i (0 .. $#construct_as) {
787 next if defined($construct_as[$i][0]); # only self table
788 if (delete $pri{$construct_as[$i][1]}) {
789 push(@pri_index, $i);
791 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
795 # no need to do an if, it'll be empty if @pri_index is empty anyway
797 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
801 do { # no need to check anything at the front, we always want the first row
805 foreach my $this_as (@construct_as) {
806 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
809 push(@const_rows, \%const);
811 } until ( # no pri_index => no collapse => drop straight out
814 do { # get another row, stash it, drop out if different PK
816 @copy = $self->cursor->next;
817 $self->{stashed_row} = \@copy;
819 # last thing in do block, counts as true if anything doesn't match
821 # check xor defined first for NULL vs. NOT NULL then if one is
822 # defined the other must be so check string equality
825 (defined $pri_vals{$_} ^ defined $copy[$_])
826 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
831 my $alias = $self->{attrs}{alias};
840 foreach my $const (@const_rows) {
841 scalar @const_keys or do {
842 @const_keys = sort { length($a) <=> length($b) } keys %$const;
844 foreach my $key (@const_keys) {
847 my @parts = split(/\./, $key);
849 my $data = $const->{$key};
850 foreach my $p (@parts) {
851 $target = $target->[1]->{$p} ||= [];
853 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
854 # collapsing at this point and on final part
855 my $pos = $collapse_pos{$cur};
856 CK: foreach my $ck (@ckey) {
857 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
858 $collapse_pos{$cur} = $data;
859 delete @collapse_pos{ # clear all positioning for sub-entries
860 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
867 if (exists $collapse{$cur}) {
868 $target = $target->[-1];
871 $target->[0] = $data;
873 $info->[0] = $const->{$key};
885 =item Arguments: $result_source?
887 =item Return Value: $result_source
891 An accessor for the primary ResultSource object from which this ResultSet
898 =item Arguments: $result_class?
900 =item Return Value: $result_class
904 An accessor for the class to use when creating row objects. Defaults to
905 C<< result_source->result_class >> - which in most cases is the name of the
906 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
915 =item Arguments: $cond, \%attrs??
917 =item Return Value: $count
921 Performs an SQL C<COUNT> with the same query as the resultset was built
922 with to find the number of elements. If passed arguments, does a search
923 on the resultset and counts the results of that.
925 Note: When using C<count> with C<group_by>, L<DBIX::Class> emulates C<GROUP BY>
926 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
927 not support C<DISTINCT> with multiple columns. If you are using such a
928 database, you should only use columns from the main table in your C<group_by>
935 return $self->search(@_)->count if @_ and defined $_[0];
936 return scalar @{ $self->get_cache } if $self->get_cache;
937 my $count = $self->_count;
938 return 0 unless $count;
940 $count -= $self->{attrs}{offset} if $self->{attrs}{offset};
941 $count = $self->{attrs}{rows} if
942 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
946 sub _count { # Separated out so pager can get the full count
948 my $select = { count => '*' };
950 my $attrs = { %{$self->_resolved_attrs} };
951 if (my $group_by = delete $attrs->{group_by}) {
952 delete $attrs->{having};
953 my @distinct = (ref $group_by ? @$group_by : ($group_by));
954 # todo: try CONCAT for multi-column pk
955 my @pk = $self->result_source->primary_columns;
957 my $alias = $attrs->{alias};
958 foreach my $column (@distinct) {
959 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
960 @distinct = ($column);
966 $select = { count => { distinct => \@distinct } };
969 $attrs->{select} = $select;
970 $attrs->{as} = [qw/count/];
972 # offset, order by and page are not needed to count. record_filter is cdbi
973 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
975 my $tmp_rs = (ref $self)->new($self->_source_handle, $attrs);
976 my ($count) = $tmp_rs->cursor->next;
984 =item Arguments: $sql_fragment, @bind_values
986 =item Return Value: $count
990 Counts the results in a literal query. Equivalent to calling L</search_literal>
991 with the passed arguments, then L</count>.
995 sub count_literal { shift->search_literal(@_)->count; }
1001 =item Arguments: none
1003 =item Return Value: @objects
1007 Returns all elements in the resultset. Called implicitly if the resultset
1008 is returned in list context.
1014 return @{ $self->get_cache } if $self->get_cache;
1018 # TODO: don't call resolve here
1019 if (keys %{$self->_resolved_attrs->{collapse}}) {
1020 # if ($self->{attrs}{prefetch}) {
1021 # Using $self->cursor->all is really just an optimisation.
1022 # If we're collapsing has_many prefetches it probably makes
1023 # very little difference, and this is cleaner than hacking
1024 # _construct_object to survive the approach
1025 my @row = $self->cursor->next;
1027 push(@obj, $self->_construct_object(@row));
1028 @row = (exists $self->{stashed_row}
1029 ? @{delete $self->{stashed_row}}
1030 : $self->cursor->next);
1033 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1036 $self->set_cache(\@obj) if $self->{attrs}{cache};
1044 =item Arguments: none
1046 =item Return Value: $self
1050 Resets the resultset's cursor, so you can iterate through the elements again.
1056 delete $self->{_attrs} if exists $self->{_attrs};
1057 $self->{all_cache_position} = 0;
1058 $self->cursor->reset;
1066 =item Arguments: none
1068 =item Return Value: $object?
1072 Resets the resultset and returns an object for the first result (if the
1073 resultset returns anything).
1078 return $_[0]->reset->next;
1081 # _cond_for_update_delete
1083 # update/delete require the condition to be modified to handle
1084 # the differing SQL syntax available. This transforms the $self->{cond}
1085 # appropriately, returning the new condition.
1087 sub _cond_for_update_delete {
1088 my ($self, $full_cond) = @_;
1091 $full_cond ||= $self->{cond};
1092 # No-op. No condition, we're updating/deleting everything
1093 return $cond unless ref $full_cond;
1095 if (ref $full_cond eq 'ARRAY') {
1099 foreach my $key (keys %{$_}) {
1101 $hash{$1} = $_->{$key};
1107 elsif (ref $full_cond eq 'HASH') {
1108 if ((keys %{$full_cond})[0] eq '-and') {
1111 my @cond = @{$full_cond->{-and}};
1112 for (my $i = 0; $i < @cond; $i++) {
1113 my $entry = $cond[$i];
1116 if (ref $entry eq 'HASH') {
1117 $hash = $self->_cond_for_update_delete($entry);
1120 $entry =~ /([^.]+)$/;
1121 $hash->{$1} = $cond[++$i];
1124 push @{$cond->{-and}}, $hash;
1128 foreach my $key (keys %{$full_cond}) {
1130 $cond->{$1} = $full_cond->{$key};
1135 $self->throw_exception(
1136 "Can't update/delete on resultset with condition unless hash or array"
1148 =item Arguments: \%values
1150 =item Return Value: $storage_rv
1154 Sets the specified columns in the resultset to the supplied values in a
1155 single query. Return value will be true if the update succeeded or false
1156 if no records were updated; exact type of success value is storage-dependent.
1161 my ($self, $values) = @_;
1162 $self->throw_exception("Values for update must be a hash")
1163 unless ref $values eq 'HASH';
1165 my $cond = $self->_cond_for_update_delete;
1167 return $self->result_source->storage->update(
1168 $self->result_source, $values, $cond
1176 =item Arguments: \%values
1178 =item Return Value: 1
1182 Fetches all objects and updates them one at a time. Note that C<update_all>
1183 will run DBIC cascade triggers, while L</update> will not.
1188 my ($self, $values) = @_;
1189 $self->throw_exception("Values for update must be a hash")
1190 unless ref $values eq 'HASH';
1191 foreach my $obj ($self->all) {
1192 $obj->set_columns($values)->update;
1201 =item Arguments: none
1203 =item Return Value: 1
1207 Deletes the contents of the resultset from its result source. Note that this
1208 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1209 to run. See also L<DBIx::Class::Row/delete>.
1216 my $cond = $self->_cond_for_update_delete;
1218 $self->result_source->storage->delete($self->result_source, $cond);
1226 =item Arguments: none
1228 =item Return Value: 1
1232 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1233 will run DBIC cascade triggers, while L</delete> will not.
1239 $_->delete for $self->all;
1247 =item Arguments: $source_name, \@data;
1251 Pass an arrayref of hashrefs. Each hashref should be a structure suitable for
1252 submitting to a $resultset->create(...) method.
1254 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1255 to insert the data, as this is a fast method.
1257 Otherwise, each set of data is inserted into the database using
1258 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1259 objects is returned.
1264 { artistid => 4, name => 'Manufactured Crap', cds => [
1265 { title => 'My First CD', year => 2006 },
1266 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1269 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1270 { title => 'My parents sold me to a record company' ,year => 2005 },
1271 { title => 'Why Am I So Ugly?', year => 2006 },
1272 { title => 'I Got Surgery and am now Popular', year => 2007 }
1275 { name => 'Like I Give a Damn' }
1280 use Data::Dump qw/dump/;
1283 my ($self, $data) = @_; #warn dump $self->result_source->primary_columns;
1285 if(defined wantarray) {
1287 foreach my $item (@$data) {
1288 push(@created, $self->create($item));
1294 my ($first, @rest) = @$data;
1296 ## We assume for now that the first item is required to name all the columns
1297 ## and relationships similarly to how schema->populate requires a first item
1298 ## of all the column names.
1300 my @names = grep { !$self->result_source->has_relationship($_) } keys %$first;
1302 $self->result_source->storage->insert_bulk(
1303 $self->result_source,
1305 [map { [ map {defined $_ ? $_ : $self->throw_exception("Undefined value for column!")} @$_{@names} ] } @$data]
1308 ## Again we assume the first row has to define all the related resultsets
1309 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1310 my @pks = $self->result_source->primary_columns;
1312 ## Must have PKs to use this!!!
1314 foreach my $item (@$data)
1316 ## First we need to get a result for each
1317 ## We need to call populate for each relationship.
1319 foreach my $rel (@rels)
1321 my $result = $self->find(map {{$_=>$item->{$_}} } @pks);
1323 my @discard = $result->$rel->populate($item->{$rel});
1324 #$result->$rel->populate($item->{$rel});
1335 =item Arguments: none
1337 =item Return Value: $pager
1341 Return Value a L<Data::Page> object for the current resultset. Only makes
1342 sense for queries with a C<page> attribute.
1348 my $attrs = $self->{attrs};
1349 $self->throw_exception("Can't create pager for non-paged rs")
1350 unless $self->{attrs}{page};
1351 $attrs->{rows} ||= 10;
1352 return $self->{pager} ||= Data::Page->new(
1353 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1360 =item Arguments: $page_number
1362 =item Return Value: $rs
1366 Returns a resultset for the $page_number page of the resultset on which page
1367 is called, where each page contains a number of rows equal to the 'rows'
1368 attribute set on the resultset (10 by default).
1373 my ($self, $page) = @_;
1374 return (ref $self)->new($self->_source_handle, { %{$self->{attrs}}, page => $page });
1381 =item Arguments: \%vals
1383 =item Return Value: $object
1387 Creates an object in the resultset's result class and returns it.
1392 my ($self, $values) = @_;
1393 $self->throw_exception( "new_result needs a hash" )
1394 unless (ref $values eq 'HASH');
1395 $self->throw_exception(
1396 "Can't abstract implicit construct, condition not a hash"
1397 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1399 my $alias = $self->{attrs}{alias};
1400 my $collapsed_cond = $self->{cond} ? $self->_collapse_cond($self->{cond}) : {};
1402 %{ $self->_remove_alias($values, $alias) },
1403 %{ $self->_remove_alias($collapsed_cond, $alias) },
1404 -source_handle => $self->_source_handle
1407 return $self->result_class->new(\%new);
1412 # Recursively collapse the condition.
1414 sub _collapse_cond {
1415 my ($self, $cond, $collapsed) = @_;
1419 if (ref $cond eq 'ARRAY') {
1420 foreach my $subcond (@$cond) {
1421 next unless ref $subcond; # -or
1422 # warn "ARRAY: " . Dumper $subcond;
1423 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1426 elsif (ref $cond eq 'HASH') {
1427 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1428 foreach my $subcond (@{$cond->{-and}}) {
1429 # warn "HASH: " . Dumper $subcond;
1430 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1434 # warn "LEAF: " . Dumper $cond;
1435 foreach my $col (keys %$cond) {
1436 my $value = $cond->{$col};
1437 $collapsed->{$col} = $value;
1447 # Remove the specified alias from the specified query hash. A copy is made so
1448 # the original query is not modified.
1451 my ($self, $query, $alias) = @_;
1453 my %orig = %{ $query || {} };
1456 foreach my $key (keys %orig) {
1458 $unaliased{$key} = $orig{$key};
1461 $unaliased{$1} = $orig{$key}
1462 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1472 =item Arguments: \%vals, \%attrs?
1474 =item Return Value: $object
1478 Find an existing record from this resultset. If none exists, instantiate a new
1479 result object and return it. The object will not be saved into your storage
1480 until you call L<DBIx::Class::Row/insert> on it.
1482 If you want objects to be saved immediately, use L</find_or_create> instead.
1488 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1489 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1490 my $exists = $self->find($hash, $attrs);
1491 return defined $exists ? $exists : $self->new_result($hash);
1498 =item Arguments: \%vals
1500 =item Return Value: $object
1504 Inserts a record into the resultset and returns the object representing it.
1506 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1511 my ($self, $attrs) = @_;
1512 $self->throw_exception( "create needs a hashref" )
1513 unless ref $attrs eq 'HASH';
1514 return $self->new_result($attrs)->insert;
1517 =head2 find_or_create
1521 =item Arguments: \%vals, \%attrs?
1523 =item Return Value: $object
1527 $class->find_or_create({ key => $val, ... });
1529 Tries to find a record based on its primary key or unique constraint; if none
1530 is found, creates one and returns that instead.
1532 my $cd = $schema->resultset('CD')->find_or_create({
1534 artist => 'Massive Attack',
1535 title => 'Mezzanine',
1539 Also takes an optional C<key> attribute, to search by a specific key or unique
1540 constraint. For example:
1542 my $cd = $schema->resultset('CD')->find_or_create(
1544 artist => 'Massive Attack',
1545 title => 'Mezzanine',
1547 { key => 'cd_artist_title' }
1550 See also L</find> and L</update_or_create>. For information on how to declare
1551 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1555 sub find_or_create {
1557 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1558 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1559 my $exists = $self->find($hash, $attrs);
1560 return defined $exists ? $exists : $self->create($hash);
1563 =head2 update_or_create
1567 =item Arguments: \%col_values, { key => $unique_constraint }?
1569 =item Return Value: $object
1573 $class->update_or_create({ col => $val, ... });
1575 First, searches for an existing row matching one of the unique constraints
1576 (including the primary key) on the source of this resultset. If a row is
1577 found, updates it with the other given column values. Otherwise, creates a new
1580 Takes an optional C<key> attribute to search on a specific unique constraint.
1583 # In your application
1584 my $cd = $schema->resultset('CD')->update_or_create(
1586 artist => 'Massive Attack',
1587 title => 'Mezzanine',
1590 { key => 'cd_artist_title' }
1593 If no C<key> is specified, it searches on all unique constraints defined on the
1594 source, including the primary key.
1596 If the C<key> is specified as C<primary>, it searches only on the primary key.
1598 See also L</find> and L</find_or_create>. For information on how to declare
1599 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1603 sub update_or_create {
1605 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1606 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
1608 my $row = $self->find($cond, $attrs);
1610 $row->update($cond);
1614 return $self->create($cond);
1621 =item Arguments: none
1623 =item Return Value: \@cache_objects?
1627 Gets the contents of the cache for the resultset, if the cache is set.
1639 =item Arguments: \@cache_objects
1641 =item Return Value: \@cache_objects
1645 Sets the contents of the cache for the resultset. Expects an arrayref
1646 of objects of the same class as those produced by the resultset. Note that
1647 if the cache is set the resultset will return the cached objects rather
1648 than re-querying the database even if the cache attr is not set.
1653 my ( $self, $data ) = @_;
1654 $self->throw_exception("set_cache requires an arrayref")
1655 if defined($data) && (ref $data ne 'ARRAY');
1656 $self->{all_cache} = $data;
1663 =item Arguments: none
1665 =item Return Value: []
1669 Clears the cache for the resultset.
1674 shift->set_cache(undef);
1677 =head2 related_resultset
1681 =item Arguments: $relationship_name
1683 =item Return Value: $resultset
1687 Returns a related resultset for the supplied relationship name.
1689 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
1693 sub related_resultset {
1694 my ($self, $rel) = @_;
1696 $self->{related_resultsets} ||= {};
1697 return $self->{related_resultsets}{$rel} ||= do {
1698 my $rel_obj = $self->result_source->relationship_info($rel);
1700 $self->throw_exception(
1701 "search_related: result source '" . $self->_source_handle->source_moniker .
1702 "' has no such relationship $rel")
1705 my ($from,$seen) = $self->_resolve_from($rel);
1707 my $join_count = $seen->{$rel};
1708 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
1710 $self->_source_handle->schema->resultset($rel_obj->{class})->search_rs(
1712 %{$self->{attrs}||{}},
1718 where => $self->{cond},
1726 my ($self, $extra_join) = @_;
1727 my $source = $self->result_source;
1728 my $attrs = $self->{attrs};
1730 my $from = $attrs->{from}
1731 || [ { $attrs->{alias} => $source->from } ];
1733 my $seen = { %{$attrs->{seen_join}||{}} };
1735 my $join = ($attrs->{join}
1736 ? [ $attrs->{join}, $extra_join ]
1740 ($join ? $source->resolve_join($join, $attrs->{alias}, $seen) : ()),
1743 return ($from,$seen);
1746 sub _resolved_attrs {
1748 return $self->{_attrs} if $self->{_attrs};
1750 my $attrs = { %{$self->{attrs}||{}} };
1751 my $source = $self->result_source;
1752 my $alias = $attrs->{alias};
1754 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
1755 if ($attrs->{columns}) {
1756 delete $attrs->{as};
1757 } elsif (!$attrs->{select}) {
1758 $attrs->{columns} = [ $source->columns ];
1763 ? (ref $attrs->{select} eq 'ARRAY'
1764 ? [ @{$attrs->{select}} ]
1765 : [ $attrs->{select} ])
1766 : [ map { m/\./ ? $_ : "${alias}.$_" } @{delete $attrs->{columns}} ]
1770 ? (ref $attrs->{as} eq 'ARRAY'
1771 ? [ @{$attrs->{as}} ]
1773 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{$attrs->{select}} ]
1777 if ($adds = delete $attrs->{include_columns}) {
1778 $adds = [$adds] unless ref $adds eq 'ARRAY';
1779 push(@{$attrs->{select}}, @$adds);
1780 push(@{$attrs->{as}}, map { m/([^.]+)$/; $1 } @$adds);
1782 if ($adds = delete $attrs->{'+select'}) {
1783 $adds = [$adds] unless ref $adds eq 'ARRAY';
1784 push(@{$attrs->{select}},
1785 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds);
1787 if (my $adds = delete $attrs->{'+as'}) {
1788 $adds = [$adds] unless ref $adds eq 'ARRAY';
1789 push(@{$attrs->{as}}, @$adds);
1792 $attrs->{from} ||= [ { 'me' => $source->from } ];
1794 if (exists $attrs->{join} || exists $attrs->{prefetch}) {
1795 my $join = delete $attrs->{join} || {};
1797 if (defined $attrs->{prefetch}) {
1798 $join = $self->_merge_attr(
1799 $join, $attrs->{prefetch}
1803 $attrs->{from} = # have to copy here to avoid corrupting the original
1806 $source->resolve_join($join, $alias, { %{$attrs->{seen_join}||{}} })
1810 $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
1811 if ($attrs->{order_by}) {
1812 $attrs->{order_by} = (ref($attrs->{order_by}) eq 'ARRAY'
1813 ? [ @{$attrs->{order_by}} ]
1814 : [ $attrs->{order_by} ]);
1816 $attrs->{order_by} = [];
1819 my $collapse = $attrs->{collapse} || {};
1820 if (my $prefetch = delete $attrs->{prefetch}) {
1821 $prefetch = $self->_merge_attr({}, $prefetch);
1823 my $seen = $attrs->{seen_join} || {};
1824 foreach my $p (ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch)) {
1825 # bring joins back to level of current class
1826 my @prefetch = $source->resolve_prefetch(
1827 $p, $alias, $seen, \@pre_order, $collapse
1829 push(@{$attrs->{select}}, map { $_->[0] } @prefetch);
1830 push(@{$attrs->{as}}, map { $_->[1] } @prefetch);
1832 push(@{$attrs->{order_by}}, @pre_order);
1834 $attrs->{collapse} = $collapse;
1836 return $self->{_attrs} = $attrs;
1840 my ($self, $a, $b) = @_;
1841 return $b unless defined($a);
1842 return $a unless defined($b);
1844 if (ref $b eq 'HASH' && ref $a eq 'HASH') {
1845 foreach my $key (keys %{$b}) {
1846 if (exists $a->{$key}) {
1847 $a->{$key} = $self->_merge_attr($a->{$key}, $b->{$key});
1849 $a->{$key} = $b->{$key};
1854 $a = [$a] unless ref $a eq 'ARRAY';
1855 $b = [$b] unless ref $b eq 'ARRAY';
1859 foreach my $x ($a, $b) {
1860 foreach my $element (@{$x}) {
1861 if (ref $element eq 'HASH') {
1862 $hash = $self->_merge_attr($hash, $element);
1863 } elsif (ref $element eq 'ARRAY') {
1864 push(@array, @{$element});
1866 push(@array, $element) unless $b == $x
1867 && grep { $_ eq $element } @array;
1872 @array = grep { !exists $hash->{$_} } @array;
1874 return keys %{$hash}
1887 $self->_source_handle($_[0]->handle);
1889 $self->_source_handle->resolve;
1893 =head2 throw_exception
1895 See L<DBIx::Class::Schema/throw_exception> for details.
1899 sub throw_exception {
1901 $self->_source_handle->schema->throw_exception(@_);
1904 # XXX: FIXME: Attributes docs need clearing up
1908 The resultset takes various attributes that modify its behavior. Here's an
1915 =item Value: ($order_by | \@order_by)
1919 Which column(s) to order the results by. This is currently passed
1920 through directly to SQL, so you can give e.g. C<year DESC> for a
1921 descending order on the column `year'.
1923 Please note that if you have C<quote_char> enabled (see
1924 L<DBIx::Class::Storage::DBI/connect_info>) you will need to do C<\'year DESC' > to
1925 specify an order. (The scalar ref causes it to be passed as raw sql to the DB,
1926 so you will need to manually quote things as appropriate.)
1932 =item Value: \@columns
1936 Shortcut to request a particular set of columns to be retrieved. Adds
1937 C<me.> onto the start of any column without a C<.> in it and sets C<select>
1938 from that, then auto-populates C<as> from C<select> as normal. (You may also
1939 use the C<cols> attribute, as in earlier versions of DBIC.)
1941 =head2 include_columns
1945 =item Value: \@columns
1949 Shortcut to include additional columns in the returned results - for example
1951 $schema->resultset('CD')->search(undef, {
1952 include_columns => ['artist.name'],
1956 would return all CDs and include a 'name' column to the information
1957 passed to object inflation. Note that the 'artist' is the name of the
1958 column (or relationship) accessor, and 'name' is the name of the column
1959 accessor in the related table.
1965 =item Value: \@select_columns
1969 Indicates which columns should be selected from the storage. You can use
1970 column names, or in the case of RDBMS back ends, function or stored procedure
1973 $rs = $schema->resultset('Employee')->search(undef, {
1976 { count => 'employeeid' },
1981 When you use function/stored procedure names and do not supply an C<as>
1982 attribute, the column names returned are storage-dependent. E.g. MySQL would
1983 return a column named C<count(employeeid)> in the above example.
1989 Indicates additional columns to be selected from storage. Works the same as
1990 L<select> but adds columns to the selection.
1998 Indicates additional column names for those added via L<+select>.
2006 =item Value: \@inflation_names
2010 Indicates column names for object inflation. That is, c< as >
2011 indicates the name that the column can be accessed as via the
2012 C<get_column> method (or via the object accessor, B<if one already
2013 exists>). It has nothing to do with the SQL code C< SELECT foo AS bar
2016 The C< as > attribute is used in conjunction with C<select>,
2017 usually when C<select> contains one or more function or stored
2020 $rs = $schema->resultset('Employee')->search(undef, {
2023 { count => 'employeeid' }
2025 as => ['name', 'employee_count'],
2028 my $employee = $rs->first(); # get the first Employee
2030 If the object against which the search is performed already has an accessor
2031 matching a column name specified in C<as>, the value can be retrieved using
2032 the accessor as normal:
2034 my $name = $employee->name();
2036 If on the other hand an accessor does not exist in the object, you need to
2037 use C<get_column> instead:
2039 my $employee_count = $employee->get_column('employee_count');
2041 You can create your own accessors if required - see
2042 L<DBIx::Class::Manual::Cookbook> for details.
2044 Please note: This will NOT insert an C<AS employee_count> into the SQL
2045 statement produced, it is used for internal access only. Thus
2046 attempting to use the accessor in an C<order_by> clause or similar
2047 will fail miserably.
2049 To get around this limitation, you can supply literal SQL to your
2050 C<select> attibute that contains the C<AS alias> text, eg:
2052 select => [\'myfield AS alias']
2058 =item Value: ($rel_name | \@rel_names | \%rel_names)
2062 Contains a list of relationships that should be joined for this query. For
2065 # Get CDs by Nine Inch Nails
2066 my $rs = $schema->resultset('CD')->search(
2067 { 'artist.name' => 'Nine Inch Nails' },
2068 { join => 'artist' }
2071 Can also contain a hash reference to refer to the other relation's relations.
2074 package MyApp::Schema::Track;
2075 use base qw/DBIx::Class/;
2076 __PACKAGE__->table('track');
2077 __PACKAGE__->add_columns(qw/trackid cd position title/);
2078 __PACKAGE__->set_primary_key('trackid');
2079 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2082 # In your application
2083 my $rs = $schema->resultset('Artist')->search(
2084 { 'track.title' => 'Teardrop' },
2086 join => { cd => 'track' },
2087 order_by => 'artist.name',
2091 You need to use the relationship (not the table) name in conditions,
2092 because they are aliased as such. The current table is aliased as "me", so
2093 you need to use me.column_name in order to avoid ambiguity. For example:
2095 # Get CDs from 1984 with a 'Foo' track
2096 my $rs = $schema->resultset('CD')->search(
2099 'tracks.name' => 'Foo'
2101 { join => 'tracks' }
2104 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2105 similarly for a third time). For e.g.
2107 my $rs = $schema->resultset('Artist')->search({
2108 'cds.title' => 'Down to Earth',
2109 'cds_2.title' => 'Popular',
2111 join => [ qw/cds cds/ ],
2114 will return a set of all artists that have both a cd with title 'Down
2115 to Earth' and a cd with title 'Popular'.
2117 If you want to fetch related objects from other tables as well, see C<prefetch>
2124 =item Value: ($rel_name | \@rel_names | \%rel_names)
2128 Contains one or more relationships that should be fetched along with the main
2129 query (when they are accessed afterwards they will have already been
2130 "prefetched"). This is useful for when you know you will need the related
2131 objects, because it saves at least one query:
2133 my $rs = $schema->resultset('Tag')->search(
2142 The initial search results in SQL like the following:
2144 SELECT tag.*, cd.*, artist.* FROM tag
2145 JOIN cd ON tag.cd = cd.cdid
2146 JOIN artist ON cd.artist = artist.artistid
2148 L<DBIx::Class> has no need to go back to the database when we access the
2149 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2152 Simple prefetches will be joined automatically, so there is no need
2153 for a C<join> attribute in the above search. If you're prefetching to
2154 depth (e.g. { cd => { artist => 'label' } or similar), you'll need to
2155 specify the join as well.
2157 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2158 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2159 with an accessor type of 'single' or 'filter').
2169 Makes the resultset paged and specifies the page to retrieve. Effectively
2170 identical to creating a non-pages resultset and then calling ->page($page)
2173 If L<rows> attribute is not specified it defualts to 10 rows per page.
2183 Specifes the maximum number of rows for direct retrieval or the number of
2184 rows per page if the page attribute or method is used.
2190 =item Value: $offset
2194 Specifies the (zero-based) row number for the first row to be returned, or the
2195 of the first row of the first page if paging is used.
2201 =item Value: \@columns
2205 A arrayref of columns to group by. Can include columns of joined tables.
2207 group_by => [qw/ column1 column2 ... /]
2213 =item Value: $condition
2217 HAVING is a select statement attribute that is applied between GROUP BY and
2218 ORDER BY. It is applied to the after the grouping calculations have been
2221 having => { 'count(employee)' => { '>=', 100 } }
2227 =item Value: (0 | 1)
2231 Set to 1 to group by all columns.
2237 Adds to the WHERE clause.
2239 # only return rows WHERE deleted IS NULL for all searches
2240 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2242 Can be overridden by passing C<{ where => undef }> as an attribute
2249 Set to 1 to cache search results. This prevents extra SQL queries if you
2250 revisit rows in your ResultSet:
2252 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2254 while( my $artist = $resultset->next ) {
2258 $rs->first; # without cache, this would issue a query
2260 By default, searches are not cached.
2262 For more examples of using these attributes, see
2263 L<DBIx::Class::Manual::Cookbook>.
2269 =item Value: \@from_clause
2273 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
2274 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
2277 NOTE: Use this on your own risk. This allows you to shoot off your foot!
2279 C<join> will usually do what you need and it is strongly recommended that you
2280 avoid using C<from> unless you cannot achieve the desired result using C<join>.
2281 And we really do mean "cannot", not just tried and failed. Attempting to use
2282 this because you're having problems with C<join> is like trying to use x86
2283 ASM because you've got a syntax error in your C. Trust us on this.
2285 Now, if you're still really, really sure you need to use this (and if you're
2286 not 100% sure, ask the mailing list first), here's an explanation of how this
2289 The syntax is as follows -
2292 { <alias1> => <table1> },
2294 { <alias2> => <table2>, -join_type => 'inner|left|right' },
2295 [], # nested JOIN (optional)
2296 { <table1.column1> => <table2.column2>, ... (more conditions) },
2298 # More of the above [ ] may follow for additional joins
2305 ON <table1.column1> = <table2.column2>
2306 <more joins may follow>
2308 An easy way to follow the examples below is to remember the following:
2310 Anything inside "[]" is a JOIN
2311 Anything inside "{}" is a condition for the enclosing JOIN
2313 The following examples utilize a "person" table in a family tree application.
2314 In order to express parent->child relationships, this table is self-joined:
2316 # Person->belongs_to('father' => 'Person');
2317 # Person->belongs_to('mother' => 'Person');
2319 C<from> can be used to nest joins. Here we return all children with a father,
2320 then search against all mothers of those children:
2322 $rs = $schema->resultset('Person')->search(
2325 alias => 'mother', # alias columns in accordance with "from"
2327 { mother => 'person' },
2330 { child => 'person' },
2332 { father => 'person' },
2333 { 'father.person_id' => 'child.father_id' }
2336 { 'mother.person_id' => 'child.mother_id' }
2343 # SELECT mother.* FROM person mother
2346 # JOIN person father
2347 # ON ( father.person_id = child.father_id )
2349 # ON ( mother.person_id = child.mother_id )
2351 The type of any join can be controlled manually. To search against only people
2352 with a father in the person table, we could explicitly use C<INNER JOIN>:
2354 $rs = $schema->resultset('Person')->search(
2357 alias => 'child', # alias columns in accordance with "from"
2359 { child => 'person' },
2361 { father => 'person', -join_type => 'inner' },
2362 { 'father.id' => 'child.father_id' }
2369 # SELECT child.* FROM person child
2370 # INNER JOIN person father ON child.father_id = father.id