1 package DBIx::Class::ResultSet;
9 use Carp::Clan qw/^DBIx::Class/;
12 use DBIx::Class::ResultSetColumn;
13 use DBIx::Class::ResultSourceHandle;
16 use base qw/DBIx::Class/;
18 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
22 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
26 my $users_rs = $schema->resultset('User');
27 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
28 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
32 A ResultSet is an object which stores a set of conditions representing
33 a query. It is the backbone of DBIx::Class (i.e. the really
34 important/useful bit).
36 No SQL is executed on the database when a ResultSet is created, it
37 just stores all the conditions needed to create the query.
39 A basic ResultSet representing the data of an entire table is returned
40 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
41 L<Source|DBIx::Class::Manual::Glossary/Source> name.
43 my $users_rs = $schema->resultset('User');
45 A new ResultSet is returned from calling L</search> on an existing
46 ResultSet. The new one will contain all the conditions of the
47 original, plus any new conditions added in the C<search> call.
49 A ResultSet is also an iterator. L</next> is used to return all the
50 L<DBIx::Class::Row>s the ResultSet represents.
52 The query that the ResultSet represents is B<only> executed against
53 the database when these methods are called:
73 =head2 Chaining resultsets
75 Let's say you've got a query that needs to be run to return some data
76 to the user. But, you have an authorization system in place that
77 prevents certain users from seeing certain information. So, you want
78 to construct the basic query in one method, but add constraints to it in
83 my $request = $self->get_request; # Get a request object somehow.
84 my $schema = $self->get_schema; # Get the DBIC schema object somehow.
86 my $cd_rs = $schema->resultset('CD')->search({
87 title => $request->param('title'),
88 year => $request->param('year'),
91 $self->apply_security_policy( $cd_rs );
96 sub apply_security_policy {
105 =head3 Resolving conditions and attributes
107 When a resultset is chained from another resultset, conditions and
108 attributes with the same keys need resolving.
110 L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
111 into the existing ones from the original resultset.
113 The L</where>, L</having> attribute, and any search conditions are
114 merged with an SQL C<AND> to the existing condition from the original
117 All other attributes are overridden by any new ones supplied in the
120 =head2 Multiple queries
122 Since a resultset just defines a query, you can do all sorts of
123 things with it with the same object.
125 # Don't hit the DB yet.
126 my $cd_rs = $schema->resultset('CD')->search({
127 title => 'something',
131 # Each of these hits the DB individually.
132 my $count = $cd_rs->count;
133 my $most_recent = $cd_rs->get_column('date_released')->max();
134 my @records = $cd_rs->all;
136 And it's not just limited to SELECT statements.
142 $cd_rs->create({ artist => 'Fred' });
144 Which is the same as:
146 $schema->resultset('CD')->create({
147 title => 'something',
152 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
156 If a resultset is used in a numeric context it returns the L</count>.
157 However, if it is used in a booleand context it is always true. So if
158 you want to check if a resultset has any results use C<if $rs != 0>.
159 C<if $rs> will always be true.
167 =item Arguments: $source, \%$attrs
169 =item Return Value: $rs
173 The resultset constructor. Takes a source object (usually a
174 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
175 L</ATTRIBUTES> below). Does not perform any queries -- these are
176 executed as needed by the other methods.
178 Generally you won't need to construct a resultset manually. You'll
179 automatically get one from e.g. a L</search> called in scalar context:
181 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
183 IMPORTANT: If called on an object, proxies to new_result instead so
185 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
187 will return a CD object, not a ResultSet.
193 return $class->new_result(@_) if ref $class;
195 my ($source, $attrs) = @_;
196 $source = $source->handle
197 unless $source->isa('DBIx::Class::ResultSourceHandle');
198 $attrs = { %{$attrs||{}} };
200 if ($attrs->{page}) {
201 $attrs->{rows} ||= 10;
204 $attrs->{alias} ||= 'me';
206 # Creation of {} and bless separated to mitigate RH perl bug
207 # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
209 _source_handle => $source,
210 cond => $attrs->{where},
219 $attrs->{result_class} || $source->resolve->result_class
229 =item Arguments: $cond, \%attrs?
231 =item Return Value: $resultset (scalar context), @row_objs (list context)
235 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
236 my $new_rs = $cd_rs->search({ year => 2005 });
238 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
239 # year = 2005 OR year = 2004
241 If you need to pass in additional attributes but no additional condition,
242 call it as C<search(undef, \%attrs)>.
244 # "SELECT name, artistid FROM $artist_table"
245 my @all_artists = $schema->resultset('Artist')->search(undef, {
246 columns => [qw/name artistid/],
249 For a list of attributes that can be passed to C<search>, see
250 L</ATTRIBUTES>. For more examples of using this function, see
251 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
252 documentation for the first argument, see L<SQL::Abstract>.
254 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
260 my $rs = $self->search_rs( @_ );
261 return (wantarray ? $rs->all : $rs);
268 =item Arguments: $cond, \%attrs?
270 =item Return Value: $resultset
274 This method does the same exact thing as search() except it will
275 always return a resultset, even in list context.
283 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
284 my $our_attrs = { %{$self->{attrs}} };
285 my $having = delete $our_attrs->{having};
286 my $where = delete $our_attrs->{where};
290 my %safe = (alias => 1, cache => 1);
293 (@_ && defined($_[0])) # @_ == () or (undef)
295 (keys %$attrs # empty attrs or only 'safe' attrs
296 && List::Util::first { !$safe{$_} } keys %$attrs)
298 # no search, effectively just a clone
299 $rows = $self->get_cache;
302 my $new_attrs = { %{$our_attrs}, %{$attrs} };
304 # merge new attrs into inherited
305 foreach my $key (qw/join prefetch +select +as/) {
306 next unless exists $attrs->{$key};
307 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
312 (@_ == 1 || ref $_[0] eq "HASH")
314 (ref $_[0] eq 'HASH')
316 (keys %{ $_[0] } > 0)
324 ? $self->throw_exception("Odd number of arguments to search")
331 if (defined $where) {
332 $new_attrs->{where} = (
333 defined $new_attrs->{where}
336 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
337 } $where, $new_attrs->{where}
344 $new_attrs->{where} = (
345 defined $new_attrs->{where}
348 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
349 } $cond, $new_attrs->{where}
355 if (defined $having) {
356 $new_attrs->{having} = (
357 defined $new_attrs->{having}
360 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
361 } $having, $new_attrs->{having}
367 my $rs = (ref $self)->new($self->result_source, $new_attrs);
369 $rs->set_cache($rows);
374 =head2 search_literal
378 =item Arguments: $sql_fragment, @bind_values
380 =item Return Value: $resultset (scalar context), @row_objs (list context)
384 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
385 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
387 Pass a literal chunk of SQL to be added to the conditional part of the
390 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
391 only be used in that context. There are known problems using C<search_literal>
392 in chained queries; it can result in bind values in the wrong order. See
393 L<DBIx::Class::Manual::Cookbook/Searching> and
394 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
395 require C<search_literal>.
400 my ($self, $cond, @vals) = @_;
401 my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
402 $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ];
403 return $self->search(\$cond, $attrs);
410 =item Arguments: @values | \%cols, \%attrs?
412 =item Return Value: $row_object | undef
416 Finds a row based on its primary key or unique constraint. For example, to find
417 a row by its primary key:
419 my $cd = $schema->resultset('CD')->find(5);
421 You can also find a row by a specific unique constraint using the C<key>
422 attribute. For example:
424 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
425 key => 'cd_artist_title'
428 Additionally, you can specify the columns explicitly by name:
430 my $cd = $schema->resultset('CD')->find(
432 artist => 'Massive Attack',
433 title => 'Mezzanine',
435 { key => 'cd_artist_title' }
438 If the C<key> is specified as C<primary>, it searches only on the primary key.
440 If no C<key> is specified, it searches on all unique constraints defined on the
441 source for which column data is provided, including the primary key.
443 If your table does not have a primary key, you B<must> provide a value for the
444 C<key> attribute matching one of the unique constraints on the source.
446 In addition to C<key>, L</find> recognizes and applies standard
447 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
449 Note: If your query does not return only one row, a warning is generated:
451 Query returned more than one row
453 See also L</find_or_create> and L</update_or_create>. For information on how to
454 declare unique constraints, see
455 L<DBIx::Class::ResultSource/add_unique_constraint>.
461 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
463 # Default to the primary key, but allow a specific key
464 my @cols = exists $attrs->{key}
465 ? $self->result_source->unique_constraint_columns($attrs->{key})
466 : $self->result_source->primary_columns;
467 $self->throw_exception(
468 "Can't find unless a primary key is defined or unique constraint is specified"
471 # Parse out a hashref from input
473 if (ref $_[0] eq 'HASH') {
474 $input_query = { %{$_[0]} };
476 elsif (@_ == @cols) {
478 @{$input_query}{@cols} = @_;
481 # Compatibility: Allow e.g. find(id => $value)
482 carp "Find by key => value deprecated; please use a hashref instead";
486 my (%related, $info);
488 KEY: foreach my $key (keys %$input_query) {
489 if (ref($input_query->{$key})
490 && ($info = $self->result_source->relationship_info($key))) {
491 my $val = delete $input_query->{$key};
492 next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
493 my $rel_q = $self->result_source->resolve_condition(
494 $info->{cond}, $val, $key
496 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
497 @related{keys %$rel_q} = values %$rel_q;
500 if (my @keys = keys %related) {
501 @{$input_query}{@keys} = values %related;
505 # Build the final query: Default to the disjunction of the unique queries,
506 # but allow the input query in case the ResultSet defines the query or the
507 # user is abusing find
508 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
510 if (exists $attrs->{key}) {
511 my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key});
512 my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
513 $query = $self->_add_alias($unique_query, $alias);
516 my @unique_queries = $self->_unique_queries($input_query, $attrs);
517 $query = @unique_queries
518 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
519 : $self->_add_alias($input_query, $alias);
524 my $rs = $self->search($query, $attrs);
525 if (keys %{$rs->_resolved_attrs->{collapse}}) {
527 carp "Query returned more than one row" if $rs->next;
535 if (keys %{$self->_resolved_attrs->{collapse}}) {
536 my $rs = $self->search($query);
538 carp "Query returned more than one row" if $rs->next;
542 return $self->single($query);
549 # Add the specified alias to the specified query hash. A copy is made so the
550 # original query is not modified.
553 my ($self, $query, $alias) = @_;
555 my %aliased = %$query;
556 foreach my $col (grep { ! m/\./ } keys %aliased) {
557 $aliased{"$alias.$col"} = delete $aliased{$col};
565 # Build a list of queries which satisfy unique constraints.
567 sub _unique_queries {
568 my ($self, $query, $attrs) = @_;
570 my @constraint_names = exists $attrs->{key}
572 : $self->result_source->unique_constraint_names;
574 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
575 my $num_where = scalar keys %$where;
578 foreach my $name (@constraint_names) {
579 my @unique_cols = $self->result_source->unique_constraint_columns($name);
580 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
582 my $num_cols = scalar @unique_cols;
583 my $num_query = scalar keys %$unique_query;
585 my $total = $num_query + $num_where;
586 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
587 # The query is either unique on its own or is unique in combination with
588 # the existing where clause
589 push @unique_queries, $unique_query;
593 return @unique_queries;
596 # _build_unique_query
598 # Constrain the specified query hash based on the specified column names.
600 sub _build_unique_query {
601 my ($self, $query, $unique_cols) = @_;
604 map { $_ => $query->{$_} }
605 grep { exists $query->{$_} }
610 =head2 search_related
614 =item Arguments: $rel, $cond, \%attrs?
616 =item Return Value: $new_resultset
620 $new_rs = $cd_rs->search_related('artist', {
624 Searches the specified relationship, optionally specifying a condition and
625 attributes for matching records. See L</ATTRIBUTES> for more information.
630 return shift->related_resultset(shift)->search(@_);
633 =head2 search_related_rs
635 This method works exactly the same as search_related, except that
636 it guarantees a restultset, even in list context.
640 sub search_related_rs {
641 return shift->related_resultset(shift)->search_rs(@_);
648 =item Arguments: none
650 =item Return Value: $cursor
654 Returns a storage-driven cursor to the given resultset. See
655 L<DBIx::Class::Cursor> for more information.
662 my $attrs = { %{$self->_resolved_attrs} };
663 return $self->{cursor}
664 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
665 $attrs->{where},$attrs);
672 =item Arguments: $cond?
674 =item Return Value: $row_object?
678 my $cd = $schema->resultset('CD')->single({ year => 2001 });
680 Inflates the first result without creating a cursor if the resultset has
681 any records in it; if not returns nothing. Used by L</find> as a lean version of
684 While this method can take an optional search condition (just like L</search>)
685 being a fast-code-path it does not recognize search attributes. If you need to
686 add extra joins or similar, call L</search> and then chain-call L</single> on the
687 L<DBIx::Class::ResultSet> returned.
693 As of 0.08100, this method enforces the assumption that the preceeding
694 query returns only one row. If more than one row is returned, you will receive
697 Query returned more than one row
699 In this case, you should be using L</first> or L</find> instead, or if you really
700 know what you are doing, use the L</rows> attribute to explicitly limit the size
708 my ($self, $where) = @_;
710 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
713 my $attrs = { %{$self->_resolved_attrs} };
715 if (defined $attrs->{where}) {
718 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
719 $where, delete $attrs->{where} ]
722 $attrs->{where} = $where;
726 # XXX: Disabled since it doesn't infer uniqueness in all cases
727 # unless ($self->_is_unique_query($attrs->{where})) {
728 # carp "Query not guaranteed to return a single row"
729 # . "; please declare your unique constraints or use search instead";
732 my @data = $self->result_source->storage->select_single(
733 $attrs->{from}, $attrs->{select},
734 $attrs->{where}, $attrs
737 return (@data ? ($self->_construct_object(@data))[0] : undef);
742 # Try to determine if the specified query is guaranteed to be unique, based on
743 # the declared unique constraints.
745 sub _is_unique_query {
746 my ($self, $query) = @_;
748 my $collapsed = $self->_collapse_query($query);
749 my $alias = $self->{attrs}{alias};
751 foreach my $name ($self->result_source->unique_constraint_names) {
752 my @unique_cols = map {
754 } $self->result_source->unique_constraint_columns($name);
756 # Count the values for each unique column
757 my %seen = map { $_ => 0 } @unique_cols;
759 foreach my $key (keys %$collapsed) {
760 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
761 next unless exists $seen{$aliased}; # Additional constraints are okay
762 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
765 # If we get 0 or more than 1 value for a column, it's not necessarily unique
766 return 1 unless grep { $_ != 1 } values %seen;
774 # Recursively collapse the query, accumulating values for each column.
776 sub _collapse_query {
777 my ($self, $query, $collapsed) = @_;
781 if (ref $query eq 'ARRAY') {
782 foreach my $subquery (@$query) {
783 next unless ref $subquery; # -or
784 # warn "ARRAY: " . Dumper $subquery;
785 $collapsed = $self->_collapse_query($subquery, $collapsed);
788 elsif (ref $query eq 'HASH') {
789 if (keys %$query and (keys %$query)[0] eq '-and') {
790 foreach my $subquery (@{$query->{-and}}) {
791 # warn "HASH: " . Dumper $subquery;
792 $collapsed = $self->_collapse_query($subquery, $collapsed);
796 # warn "LEAF: " . Dumper $query;
797 foreach my $col (keys %$query) {
798 my $value = $query->{$col};
799 $collapsed->{$col}{$value}++;
811 =item Arguments: $cond?
813 =item Return Value: $resultsetcolumn
817 my $max_length = $rs->get_column('length')->max;
819 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
824 my ($self, $column) = @_;
825 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
833 =item Arguments: $cond, \%attrs?
835 =item Return Value: $resultset (scalar context), @row_objs (list context)
839 # WHERE title LIKE '%blue%'
840 $cd_rs = $rs->search_like({ title => '%blue%'});
842 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
843 that this is simply a convenience method retained for ex Class::DBI users.
844 You most likely want to use L</search> with specific operators.
846 For more information, see L<DBIx::Class::Manual::Cookbook>.
852 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
853 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
854 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
855 return $class->search($query, { %$attrs });
862 =item Arguments: $first, $last
864 =item Return Value: $resultset (scalar context), @row_objs (list context)
868 Returns a resultset or object list representing a subset of elements from the
869 resultset slice is called on. Indexes are from 0, i.e., to get the first
872 my ($one, $two, $three) = $rs->slice(0, 2);
877 my ($self, $min, $max) = @_;
878 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
879 $attrs->{offset} = $self->{attrs}{offset} || 0;
880 $attrs->{offset} += $min;
881 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
882 return $self->search(undef(), $attrs);
883 #my $slice = (ref $self)->new($self->result_source, $attrs);
884 #return (wantarray ? $slice->all : $slice);
891 =item Arguments: none
893 =item Return Value: $result?
897 Returns the next element in the resultset (C<undef> is there is none).
899 Can be used to efficiently iterate over records in the resultset:
901 my $rs = $schema->resultset('CD')->search;
902 while (my $cd = $rs->next) {
906 Note that you need to store the resultset object, and call C<next> on it.
907 Calling C<< resultset('Table')->next >> repeatedly will always return the
908 first record from the resultset.
914 if (my $cache = $self->get_cache) {
915 $self->{all_cache_position} ||= 0;
916 return $cache->[$self->{all_cache_position}++];
918 if ($self->{attrs}{cache}) {
919 $self->{all_cache_position} = 1;
920 return ($self->all)[0];
922 if ($self->{stashed_objects}) {
923 my $obj = shift(@{$self->{stashed_objects}});
924 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
928 exists $self->{stashed_row}
929 ? @{delete $self->{stashed_row}}
930 : $self->cursor->next
932 return undef unless (@row);
933 my ($row, @more) = $self->_construct_object(@row);
934 $self->{stashed_objects} = \@more if @more;
938 sub _construct_object {
939 my ($self, @row) = @_;
940 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
941 my @new = $self->result_class->inflate_result($self->result_source, @$info);
942 @new = $self->{_attrs}{record_filter}->(@new)
943 if exists $self->{_attrs}{record_filter};
947 sub _collapse_result {
948 my ($self, $as_proto, $row) = @_;
952 # 'foo' => [ undef, 'foo' ]
953 # 'foo.bar' => [ 'foo', 'bar' ]
954 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
956 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
958 my %collapse = %{$self->{_attrs}{collapse}||{}};
962 # if we're doing collapsing (has_many prefetch) we need to grab records
963 # until the PK changes, so fill @pri_index. if not, we leave it empty so
964 # we know we don't have to bother.
966 # the reason for not using the collapse stuff directly is because if you
967 # had for e.g. two artists in a row with no cds, the collapse info for
968 # both would be NULL (undef) so you'd lose the second artist
970 # store just the index so we can check the array positions from the row
971 # without having to contruct the full hash
973 if (keys %collapse) {
974 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
975 foreach my $i (0 .. $#construct_as) {
976 next if defined($construct_as[$i][0]); # only self table
977 if (delete $pri{$construct_as[$i][1]}) {
978 push(@pri_index, $i);
980 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
984 # no need to do an if, it'll be empty if @pri_index is empty anyway
986 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
990 do { # no need to check anything at the front, we always want the first row
994 foreach my $this_as (@construct_as) {
995 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
998 push(@const_rows, \%const);
1000 } until ( # no pri_index => no collapse => drop straight out
1003 do { # get another row, stash it, drop out if different PK
1005 @copy = $self->cursor->next;
1006 $self->{stashed_row} = \@copy;
1008 # last thing in do block, counts as true if anything doesn't match
1010 # check xor defined first for NULL vs. NOT NULL then if one is
1011 # defined the other must be so check string equality
1014 (defined $pri_vals{$_} ^ defined $copy[$_])
1015 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1020 my $alias = $self->{attrs}{alias};
1027 foreach my $const (@const_rows) {
1028 scalar @const_keys or do {
1029 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1031 foreach my $key (@const_keys) {
1034 my @parts = split(/\./, $key);
1036 my $data = $const->{$key};
1037 foreach my $p (@parts) {
1038 $target = $target->[1]->{$p} ||= [];
1040 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1041 # collapsing at this point and on final part
1042 my $pos = $collapse_pos{$cur};
1043 CK: foreach my $ck (@ckey) {
1044 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1045 $collapse_pos{$cur} = $data;
1046 delete @collapse_pos{ # clear all positioning for sub-entries
1047 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1054 if (exists $collapse{$cur}) {
1055 $target = $target->[-1];
1058 $target->[0] = $data;
1060 $info->[0] = $const->{$key};
1068 =head2 result_source
1072 =item Arguments: $result_source?
1074 =item Return Value: $result_source
1078 An accessor for the primary ResultSource object from which this ResultSet
1085 =item Arguments: $result_class?
1087 =item Return Value: $result_class
1091 An accessor for the class to use when creating row objects. Defaults to
1092 C<< result_source->result_class >> - which in most cases is the name of the
1093 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1098 my ($self, $result_class) = @_;
1099 if ($result_class) {
1100 $self->ensure_class_loaded($result_class);
1101 $self->_result_class($result_class);
1103 $self->_result_class;
1110 =item Arguments: $cond, \%attrs??
1112 =item Return Value: $count
1116 Performs an SQL C<COUNT> with the same query as the resultset was built
1117 with to find the number of elements. If passed arguments, does a search
1118 on the resultset and counts the results of that.
1124 return $self->search(@_)->count if @_ and defined $_[0];
1125 return scalar @{ $self->get_cache } if $self->get_cache;
1126 my $count = $self->_count;
1127 return 0 unless $count;
1129 # need to take offset from resolved attrs
1131 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1132 $count = $self->{attrs}{rows} if
1133 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1134 $count = 0 if ($count < 0);
1138 sub _count { # Separated out so pager can get the full count
1140 my $attrs = { %{$self->_resolved_attrs} };
1142 if (my $group_by = $attrs->{group_by}) {
1143 delete $attrs->{order_by};
1145 $attrs->{select} = $group_by;
1146 $attrs->{from} = [ { 'mesub' => (ref $self)->new($self->result_source, $attrs)->cursor->as_query } ];
1147 delete $attrs->{where};
1150 $attrs->{select} = { count => '*' };
1151 $attrs->{as} = [qw/count/];
1153 # offset, order by, group by, where and page are not needed to count. record_filter is cdbi
1154 delete $attrs->{$_} for qw/rows offset order_by group_by page pager record_filter/;
1156 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1157 my ($count) = $tmp_rs->cursor->next;
1165 =head2 count_literal
1169 =item Arguments: $sql_fragment, @bind_values
1171 =item Return Value: $count
1175 Counts the results in a literal query. Equivalent to calling L</search_literal>
1176 with the passed arguments, then L</count>.
1180 sub count_literal { shift->search_literal(@_)->count; }
1186 =item Arguments: none
1188 =item Return Value: @objects
1192 Returns all elements in the resultset. Called implicitly if the resultset
1193 is returned in list context.
1200 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1203 return @{ $self->get_cache } if $self->get_cache;
1207 # TODO: don't call resolve here
1208 if (keys %{$self->_resolved_attrs->{collapse}}) {
1209 # if ($self->{attrs}{prefetch}) {
1210 # Using $self->cursor->all is really just an optimisation.
1211 # If we're collapsing has_many prefetches it probably makes
1212 # very little difference, and this is cleaner than hacking
1213 # _construct_object to survive the approach
1214 my @row = $self->cursor->next;
1216 push(@obj, $self->_construct_object(@row));
1217 @row = (exists $self->{stashed_row}
1218 ? @{delete $self->{stashed_row}}
1219 : $self->cursor->next);
1222 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1225 $self->set_cache(\@obj) if $self->{attrs}{cache};
1233 =item Arguments: none
1235 =item Return Value: $self
1239 Resets the resultset's cursor, so you can iterate through the elements again.
1245 delete $self->{_attrs} if exists $self->{_attrs};
1246 $self->{all_cache_position} = 0;
1247 $self->cursor->reset;
1255 =item Arguments: none
1257 =item Return Value: $object?
1261 Resets the resultset and returns an object for the first result (if the
1262 resultset returns anything).
1267 return $_[0]->reset->next;
1270 # _cond_for_update_delete
1272 # update/delete require the condition to be modified to handle
1273 # the differing SQL syntax available. This transforms the $self->{cond}
1274 # appropriately, returning the new condition.
1276 sub _cond_for_update_delete {
1277 my ($self, $full_cond) = @_;
1280 $full_cond ||= $self->{cond};
1281 # No-op. No condition, we're updating/deleting everything
1282 return $cond unless ref $full_cond;
1284 if (ref $full_cond eq 'ARRAY') {
1288 foreach my $key (keys %{$_}) {
1290 $hash{$1} = $_->{$key};
1296 elsif (ref $full_cond eq 'HASH') {
1297 if ((keys %{$full_cond})[0] eq '-and') {
1300 my @cond = @{$full_cond->{-and}};
1301 for (my $i = 0; $i < @cond; $i++) {
1302 my $entry = $cond[$i];
1305 if (ref $entry eq 'HASH') {
1306 $hash = $self->_cond_for_update_delete($entry);
1309 $entry =~ /([^.]+)$/;
1310 $hash->{$1} = $cond[++$i];
1313 push @{$cond->{-and}}, $hash;
1317 foreach my $key (keys %{$full_cond}) {
1319 $cond->{$1} = $full_cond->{$key};
1324 $self->throw_exception(
1325 "Can't update/delete on resultset with condition unless hash or array"
1337 =item Arguments: \%values
1339 =item Return Value: $storage_rv
1343 Sets the specified columns in the resultset to the supplied values in a
1344 single query. Return value will be true if the update succeeded or false
1345 if no records were updated; exact type of success value is storage-dependent.
1350 my ($self, $values) = @_;
1351 $self->throw_exception("Values for update must be a hash")
1352 unless ref $values eq 'HASH';
1354 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1355 . ' on joined resultsets, and may affect rows well outside of the'
1356 . ' contents of $rs. Use at your own risk' )
1357 if ( $self->{attrs}{seen_join} );
1359 my $cond = $self->_cond_for_update_delete;
1361 return $self->result_source->storage->update(
1362 $self->result_source, $values, $cond
1370 =item Arguments: \%values
1372 =item Return Value: 1
1376 Fetches all objects and updates them one at a time. Note that C<update_all>
1377 will run DBIC cascade triggers, while L</update> will not.
1382 my ($self, $values) = @_;
1383 $self->throw_exception("Values for update must be a hash")
1384 unless ref $values eq 'HASH';
1385 foreach my $obj ($self->all) {
1386 $obj->set_columns($values)->update;
1395 =item Arguments: none
1397 =item Return Value: 1
1401 Deletes the contents of the resultset from its result source. Note that this
1402 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1403 to run. See also L<DBIx::Class::Row/delete>.
1405 delete may not generate correct SQL for a query with joins or a resultset
1406 chained from a related resultset. In this case it will generate a warning:-
1408 WARNING! Currently $rs->delete() does not generate proper SQL on
1409 joined resultsets, and may delete rows well outside of the contents
1410 of $rs. Use at your own risk
1412 In these cases you may find that delete_all is more appropriate, or you
1413 need to respecify your query in a way that can be expressed without a join.
1419 $self->throw_exception("Delete should not be passed any arguments")
1421 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1422 . ' on joined resultsets, and may delete rows well outside of the'
1423 . ' contents of $rs. Use at your own risk' )
1424 if ( $self->{attrs}{seen_join} );
1425 my $cond = $self->_cond_for_update_delete;
1427 $self->result_source->storage->delete($self->result_source, $cond);
1435 =item Arguments: none
1437 =item Return Value: 1
1441 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1442 will run DBIC cascade triggers, while L</delete> will not.
1448 $_->delete for $self->all;
1456 =item Arguments: \@data;
1460 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1461 For the arrayref of hashrefs style each hashref should be a structure suitable
1462 forsubmitting to a $resultset->create(...) method.
1464 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1465 to insert the data, as this is a faster method.
1467 Otherwise, each set of data is inserted into the database using
1468 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1469 objects is returned.
1471 Example: Assuming an Artist Class that has many CDs Classes relating:
1473 my $Artist_rs = $schema->resultset("Artist");
1475 ## Void Context Example
1476 $Artist_rs->populate([
1477 { artistid => 4, name => 'Manufactured Crap', cds => [
1478 { title => 'My First CD', year => 2006 },
1479 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1482 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1483 { title => 'My parents sold me to a record company' ,year => 2005 },
1484 { title => 'Why Am I So Ugly?', year => 2006 },
1485 { title => 'I Got Surgery and am now Popular', year => 2007 }
1490 ## Array Context Example
1491 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1492 { name => "Artist One"},
1493 { name => "Artist Two"},
1494 { name => "Artist Three", cds=> [
1495 { title => "First CD", year => 2007},
1496 { title => "Second CD", year => 2008},
1500 print $ArtistOne->name; ## response is 'Artist One'
1501 print $ArtistThree->cds->count ## reponse is '2'
1503 For the arrayref of arrayrefs style, the first element should be a list of the
1504 fieldsnames to which the remaining elements are rows being inserted. For
1507 $Arstist_rs->populate([
1508 [qw/artistid name/],
1509 [100, 'A Formally Unknown Singer'],
1510 [101, 'A singer that jumped the shark two albums ago'],
1511 [102, 'An actually cool singer.'],
1514 Please note an important effect on your data when choosing between void and
1515 wantarray context. Since void context goes straight to C<insert_bulk> in
1516 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1517 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1518 create primary keys for you, you will find that your PKs are empty. In this
1519 case you will have to use the wantarray context in order to create those
1525 my $self = shift @_;
1526 my $data = ref $_[0][0] eq 'HASH'
1527 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1528 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1530 if(defined wantarray) {
1532 foreach my $item (@$data) {
1533 push(@created, $self->create($item));
1537 my ($first, @rest) = @$data;
1539 my @names = grep {!ref $first->{$_}} keys %$first;
1540 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1541 my @pks = $self->result_source->primary_columns;
1543 ## do the belongs_to relationships
1544 foreach my $index (0..$#$data) {
1545 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1546 my @ret = $self->populate($data);
1550 foreach my $rel (@rels) {
1551 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1552 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1553 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1554 my $related = $result->result_source->resolve_condition(
1555 $result->result_source->relationship_info($reverse)->{cond},
1560 delete $data->[$index]->{$rel};
1561 $data->[$index] = {%{$data->[$index]}, %$related};
1563 push @names, keys %$related if $index == 0;
1567 ## do bulk insert on current row
1568 my @values = map { [ @$_{@names} ] } @$data;
1570 $self->result_source->storage->insert_bulk(
1571 $self->result_source,
1576 ## do the has_many relationships
1577 foreach my $item (@$data) {
1579 foreach my $rel (@rels) {
1580 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1582 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1583 || $self->throw_exception('Cannot find the relating object.');
1585 my $child = $parent->$rel;
1587 my $related = $child->result_source->resolve_condition(
1588 $parent->result_source->relationship_info($rel)->{cond},
1593 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1594 my @populate = map { {%$_, %$related} } @rows_to_add;
1596 $child->populate( \@populate );
1602 =head2 _normalize_populate_args ($args)
1604 Private method used by L</populate> to normalize its incoming arguments. Factored
1605 out in case you want to subclass and accept new argument structures to the
1606 L</populate> method.
1610 sub _normalize_populate_args {
1611 my ($self, $data) = @_;
1612 my @names = @{shift(@$data)};
1613 my @results_to_create;
1614 foreach my $datum (@$data) {
1615 my %result_to_create;
1616 foreach my $index (0..$#names) {
1617 $result_to_create{$names[$index]} = $$datum[$index];
1619 push @results_to_create, \%result_to_create;
1621 return \@results_to_create;
1628 =item Arguments: none
1630 =item Return Value: $pager
1634 Return Value a L<Data::Page> object for the current resultset. Only makes
1635 sense for queries with a C<page> attribute.
1637 To get the full count of entries for a paged resultset, call
1638 C<total_entries> on the L<Data::Page> object.
1644 my $attrs = $self->{attrs};
1645 $self->throw_exception("Can't create pager for non-paged rs")
1646 unless $self->{attrs}{page};
1647 $attrs->{rows} ||= 10;
1648 return $self->{pager} ||= Data::Page->new(
1649 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1656 =item Arguments: $page_number
1658 =item Return Value: $rs
1662 Returns a resultset for the $page_number page of the resultset on which page
1663 is called, where each page contains a number of rows equal to the 'rows'
1664 attribute set on the resultset (10 by default).
1669 my ($self, $page) = @_;
1670 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1677 =item Arguments: \%vals
1679 =item Return Value: $rowobject
1683 Creates a new row object in the resultset's result class and returns
1684 it. The row is not inserted into the database at this point, call
1685 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1686 will tell you whether the row object has been inserted or not.
1688 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1693 my ($self, $values) = @_;
1694 $self->throw_exception( "new_result needs a hash" )
1695 unless (ref $values eq 'HASH');
1698 my $alias = $self->{attrs}{alias};
1701 defined $self->{cond}
1702 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1704 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1705 $new{-from_resultset} = [ keys %new ] if keys %new;
1707 $self->throw_exception(
1708 "Can't abstract implicit construct, condition not a hash"
1709 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1711 my $collapsed_cond = (
1713 ? $self->_collapse_cond($self->{cond})
1717 # precendence must be given to passed values over values inherited from
1718 # the cond, so the order here is important.
1719 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1720 while( my($col,$value) = each %implied ){
1721 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1722 $new{$col} = $value->{'='};
1725 $new{$col} = $value if $self->_is_deterministic_value($value);
1731 %{ $self->_remove_alias($values, $alias) },
1732 -source_handle => $self->_source_handle,
1733 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1736 return $self->result_class->new(\%new);
1739 # _is_deterministic_value
1741 # Make an effor to strip non-deterministic values from the condition,
1742 # to make sure new_result chokes less
1744 sub _is_deterministic_value {
1747 my $ref_type = ref $value;
1748 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1749 return 1 if Scalar::Util::blessed($value);
1755 # Recursively collapse the condition.
1757 sub _collapse_cond {
1758 my ($self, $cond, $collapsed) = @_;
1762 if (ref $cond eq 'ARRAY') {
1763 foreach my $subcond (@$cond) {
1764 next unless ref $subcond; # -or
1765 # warn "ARRAY: " . Dumper $subcond;
1766 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1769 elsif (ref $cond eq 'HASH') {
1770 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1771 foreach my $subcond (@{$cond->{-and}}) {
1772 # warn "HASH: " . Dumper $subcond;
1773 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1777 # warn "LEAF: " . Dumper $cond;
1778 foreach my $col (keys %$cond) {
1779 my $value = $cond->{$col};
1780 $collapsed->{$col} = $value;
1790 # Remove the specified alias from the specified query hash. A copy is made so
1791 # the original query is not modified.
1794 my ($self, $query, $alias) = @_;
1796 my %orig = %{ $query || {} };
1799 foreach my $key (keys %orig) {
1801 $unaliased{$key} = $orig{$key};
1804 $unaliased{$1} = $orig{$key}
1805 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1811 =head2 as_query (EXPERIMENTAL)
1815 =item Arguments: none
1817 =item Return Value: \[ $sql, @bind ]
1821 Returns the SQL query and bind vars associated with the invocant.
1823 This is generally used as the RHS for a subquery.
1825 B<NOTE>: This feature is still experimental.
1829 sub as_query { return shift->cursor->as_query(@_) }
1835 =item Arguments: \%vals, \%attrs?
1837 =item Return Value: $rowobject
1841 my $artist = $schema->resultset('Artist')->find_or_new(
1842 { artist => 'fred' }, { key => 'artists' });
1844 $cd->cd_to_producer->find_or_new({ producer => $producer },
1845 { key => 'primary });
1847 Find an existing record from this resultset, based on its primary
1848 key, or a unique constraint. If none exists, instantiate a new result
1849 object and return it. The object will not be saved into your storage
1850 until you call L<DBIx::Class::Row/insert> on it.
1852 You most likely want this method when looking for existing rows using
1853 a unique constraint that is not the primary key, or looking for
1856 If you want objects to be saved immediately, use L</find_or_create> instead.
1858 B<Note>: C<find_or_new> is probably not what you want when creating a
1859 new row in a table that uses primary keys supplied by the
1860 database. Passing in a primary key column with a value of I<undef>
1861 will cause L</find> to attempt to search for a row with a value of
1868 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1869 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1870 my $exists = $self->find($hash, $attrs);
1871 return defined $exists ? $exists : $self->new_result($hash);
1878 =item Arguments: \%vals
1880 =item Return Value: a L<DBIx::Class::Row> $object
1884 Attempt to create a single new row or a row with multiple related rows
1885 in the table represented by the resultset (and related tables). This
1886 will not check for duplicate rows before inserting, use
1887 L</find_or_create> to do that.
1889 To create one row for this resultset, pass a hashref of key/value
1890 pairs representing the columns of the table and the values you wish to
1891 store. If the appropriate relationships are set up, foreign key fields
1892 can also be passed an object representing the foreign row, and the
1893 value will be set to its primary key.
1895 To create related objects, pass a hashref for the value if the related
1896 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1897 and use the name of the relationship as the key. (NOT the name of the field,
1898 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1899 of hashrefs containing the data for each of the rows to create in the foreign
1900 tables, again using the relationship name as the key.
1902 Instead of hashrefs of plain related data (key/value pairs), you may
1903 also pass new or inserted objects. New objects (not inserted yet, see
1904 L</new>), will be inserted into their appropriate tables.
1906 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1908 Example of creating a new row.
1910 $person_rs->create({
1911 name=>"Some Person",
1912 email=>"somebody@someplace.com"
1915 Example of creating a new row and also creating rows in a related C<has_many>
1916 or C<has_one> resultset. Note Arrayref.
1919 { artistid => 4, name => 'Manufactured Crap', cds => [
1920 { title => 'My First CD', year => 2006 },
1921 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1926 Example of creating a new row and also creating a row in a related
1927 C<belongs_to>resultset. Note Hashref.
1930 title=>"Music for Silly Walks",
1933 name=>"Silly Musician",
1940 my ($self, $attrs) = @_;
1941 $self->throw_exception( "create needs a hashref" )
1942 unless ref $attrs eq 'HASH';
1943 return $self->new_result($attrs)->insert;
1946 =head2 find_or_create
1950 =item Arguments: \%vals, \%attrs?
1952 =item Return Value: $rowobject
1956 $cd->cd_to_producer->find_or_create({ producer => $producer },
1957 { key => 'primary });
1959 Tries to find a record based on its primary key or unique constraints; if none
1960 is found, creates one and returns that instead.
1962 my $cd = $schema->resultset('CD')->find_or_create({
1964 artist => 'Massive Attack',
1965 title => 'Mezzanine',
1969 Also takes an optional C<key> attribute, to search by a specific key or unique
1970 constraint. For example:
1972 my $cd = $schema->resultset('CD')->find_or_create(
1974 artist => 'Massive Attack',
1975 title => 'Mezzanine',
1977 { key => 'cd_artist_title' }
1980 B<Note>: Because find_or_create() reads from the database and then
1981 possibly inserts based on the result, this method is subject to a race
1982 condition. Another process could create a record in the table after
1983 the find has completed and before the create has started. To avoid
1984 this problem, use find_or_create() inside a transaction.
1986 B<Note>: C<find_or_create> is probably not what you want when creating
1987 a new row in a table that uses primary keys supplied by the
1988 database. Passing in a primary key column with a value of I<undef>
1989 will cause L</find> to attempt to search for a row with a value of
1992 See also L</find> and L</update_or_create>. For information on how to declare
1993 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1997 sub find_or_create {
1999 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2000 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2001 my $exists = $self->find($hash, $attrs);
2002 return defined $exists ? $exists : $self->create($hash);
2005 =head2 update_or_create
2009 =item Arguments: \%col_values, { key => $unique_constraint }?
2011 =item Return Value: $rowobject
2015 $resultset->update_or_create({ col => $val, ... });
2017 First, searches for an existing row matching one of the unique constraints
2018 (including the primary key) on the source of this resultset. If a row is
2019 found, updates it with the other given column values. Otherwise, creates a new
2022 Takes an optional C<key> attribute to search on a specific unique constraint.
2025 # In your application
2026 my $cd = $schema->resultset('CD')->update_or_create(
2028 artist => 'Massive Attack',
2029 title => 'Mezzanine',
2032 { key => 'cd_artist_title' }
2035 $cd->cd_to_producer->update_or_create({
2036 producer => $producer,
2043 If no C<key> is specified, it searches on all unique constraints defined on the
2044 source, including the primary key.
2046 If the C<key> is specified as C<primary>, it searches only on the primary key.
2048 See also L</find> and L</find_or_create>. For information on how to declare
2049 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2051 B<Note>: C<update_or_create> is probably not what you want when
2052 looking for a row in a table that uses primary keys supplied by the
2053 database, unless you actually have a key value. Passing in a primary
2054 key column with a value of I<undef> will cause L</find> to attempt to
2055 search for a row with a value of I<NULL>.
2059 sub update_or_create {
2061 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2062 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2064 my $row = $self->find($cond, $attrs);
2066 $row->update($cond);
2070 return $self->create($cond);
2077 =item Arguments: none
2079 =item Return Value: \@cache_objects?
2083 Gets the contents of the cache for the resultset, if the cache is set.
2085 The cache is populated either by using the L</prefetch> attribute to
2086 L</search> or by calling L</set_cache>.
2098 =item Arguments: \@cache_objects
2100 =item Return Value: \@cache_objects
2104 Sets the contents of the cache for the resultset. Expects an arrayref
2105 of objects of the same class as those produced by the resultset. Note that
2106 if the cache is set the resultset will return the cached objects rather
2107 than re-querying the database even if the cache attr is not set.
2109 The contents of the cache can also be populated by using the
2110 L</prefetch> attribute to L</search>.
2115 my ( $self, $data ) = @_;
2116 $self->throw_exception("set_cache requires an arrayref")
2117 if defined($data) && (ref $data ne 'ARRAY');
2118 $self->{all_cache} = $data;
2125 =item Arguments: none
2127 =item Return Value: []
2131 Clears the cache for the resultset.
2136 shift->set_cache(undef);
2139 =head2 related_resultset
2143 =item Arguments: $relationship_name
2145 =item Return Value: $resultset
2149 Returns a related resultset for the supplied relationship name.
2151 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2155 sub related_resultset {
2156 my ($self, $rel) = @_;
2158 $self->{related_resultsets} ||= {};
2159 return $self->{related_resultsets}{$rel} ||= do {
2160 my $rel_obj = $self->result_source->relationship_info($rel);
2162 $self->throw_exception(
2163 "search_related: result source '" . $self->result_source->source_name .
2164 "' has no such relationship $rel")
2167 my ($from,$seen) = $self->_resolve_from($rel);
2169 my $join_count = $seen->{$rel};
2170 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2172 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2173 my %attrs = %{$self->{attrs}||{}};
2174 delete @attrs{qw(result_class alias)};
2178 if (my $cache = $self->get_cache) {
2179 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2180 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2185 my $rel_source = $self->result_source->related_source($rel);
2189 # The reason we do this now instead of passing the alias to the
2190 # search_rs below is that if you wrap/overload resultset on the
2191 # source you need to know what alias it's -going- to have for things
2192 # to work sanely (e.g. RestrictWithObject wants to be able to add
2193 # extra query restrictions, and these may need to be $alias.)
2195 my $attrs = $rel_source->resultset_attributes;
2196 local $attrs->{alias} = $alias;
2198 $rel_source->resultset
2206 where => $self->{cond},
2211 $new->set_cache($new_cache) if $new_cache;
2216 =head2 current_source_alias
2220 =item Arguments: none
2222 =item Return Value: $source_alias
2226 Returns the current table alias for the result source this resultset is built
2227 on, that will be used in the SQL query. Usually it is C<me>.
2229 Currently the source alias that refers to the result set returned by a
2230 L</search>/L</find> family method depends on how you got to the resultset: it's
2231 C<me> by default, but eg. L</search_related> aliases it to the related result
2232 source name (and keeps C<me> referring to the original result set). The long
2233 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2234 (and make this method unnecessary).
2236 Thus it's currently necessary to use this method in predefined queries (see
2237 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2238 source alias of the current result set:
2240 # in a result set class
2242 my ($self, $user) = @_;
2244 my $me = $self->current_source_alias;
2246 return $self->search(
2247 "$me.modified" => $user->id,
2253 sub current_source_alias {
2256 return ($self->{attrs} || {})->{alias} || 'me';
2260 my ($self, $extra_join) = @_;
2261 my $source = $self->result_source;
2262 my $attrs = $self->{attrs};
2264 my $from = $attrs->{from}
2265 || [ { $attrs->{alias} => $source->from } ];
2267 my $seen = { %{$attrs->{seen_join}||{}} };
2269 my $join = ($attrs->{join}
2270 ? [ $attrs->{join}, $extra_join ]
2273 # we need to take the prefetch the attrs into account before we
2274 # ->resolve_join as otherwise they get lost - captainL
2275 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2279 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2282 return ($from,$seen);
2285 sub _resolved_attrs {
2287 return $self->{_attrs} if $self->{_attrs};
2289 my $attrs = { %{ $self->{attrs} || {} } };
2290 my $source = $self->result_source;
2291 my $alias = $attrs->{alias};
2293 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2296 # build columns (as long as select isn't set) into a set of as/select hashes
2297 unless ( $attrs->{select} ) {
2299 ( ref($_) eq 'HASH' ) ? $_
2302 /^\Q${alias}.\E(.+)$/ ? $1
2304 ) => ( /\./ ? $_ : "${alias}.$_" )
2306 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2308 # add the additional columns on
2309 foreach ( 'include_columns', '+columns' ) {
2310 push @colbits, map {
2311 ( ref($_) eq 'HASH' )
2313 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2314 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2317 # start with initial select items
2318 if ( $attrs->{select} ) {
2320 ( ref $attrs->{select} eq 'ARRAY' )
2321 ? [ @{ $attrs->{select} } ]
2322 : [ $attrs->{select} ];
2326 ref $attrs->{as} eq 'ARRAY'
2327 ? [ @{ $attrs->{as} } ]
2330 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2335 # otherwise we intialise select & as to empty
2336 $attrs->{select} = [];
2340 # now add colbits to select/as
2341 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2342 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2345 if ( $adds = delete $attrs->{'+select'} ) {
2346 $adds = [$adds] unless ref $adds eq 'ARRAY';
2348 @{ $attrs->{select} },
2349 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2352 if ( $adds = delete $attrs->{'+as'} ) {
2353 $adds = [$adds] unless ref $adds eq 'ARRAY';
2354 push( @{ $attrs->{as} }, @$adds );
2357 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2359 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2360 my $join = delete $attrs->{join} || {};
2362 if ( defined $attrs->{prefetch} ) {
2363 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2367 $attrs->{from} = # have to copy here to avoid corrupting the original
2369 @{ $attrs->{from} },
2370 $source->resolve_join(
2371 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2377 $attrs->{group_by} ||= $attrs->{select}
2378 if delete $attrs->{distinct};
2379 if ( $attrs->{order_by} ) {
2380 $attrs->{order_by} = (
2381 ref( $attrs->{order_by} ) eq 'ARRAY'
2382 ? [ @{ $attrs->{order_by} } ]
2383 : [ $attrs->{order_by} ]
2387 $attrs->{order_by} = [];
2390 my $collapse = $attrs->{collapse} || {};
2391 if ( my $prefetch = delete $attrs->{prefetch} ) {
2392 $prefetch = $self->_merge_attr( {}, $prefetch );
2394 my $seen = { %{ $attrs->{seen_join} || {} } };
2395 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2397 # bring joins back to level of current class
2399 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2400 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2401 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2403 push( @{ $attrs->{order_by} }, @pre_order );
2405 $attrs->{collapse} = $collapse;
2407 if ( $attrs->{page} ) {
2408 $attrs->{offset} ||= 0;
2409 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2412 return $self->{_attrs} = $attrs;
2416 my ($self, $attr) = @_;
2418 if (ref $attr eq 'HASH') {
2419 return $self->_rollout_hash($attr);
2420 } elsif (ref $attr eq 'ARRAY') {
2421 return $self->_rollout_array($attr);
2427 sub _rollout_array {
2428 my ($self, $attr) = @_;
2431 foreach my $element (@{$attr}) {
2432 if (ref $element eq 'HASH') {
2433 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2434 } elsif (ref $element eq 'ARRAY') {
2435 # XXX - should probably recurse here
2436 push( @rolled_array, @{$self->_rollout_array($element)} );
2438 push( @rolled_array, $element );
2441 return \@rolled_array;
2445 my ($self, $attr) = @_;
2448 foreach my $key (keys %{$attr}) {
2449 push( @rolled_array, { $key => $attr->{$key} } );
2451 return \@rolled_array;
2454 sub _calculate_score {
2455 my ($self, $a, $b) = @_;
2457 if (ref $b eq 'HASH') {
2458 my ($b_key) = keys %{$b};
2459 if (ref $a eq 'HASH') {
2460 my ($a_key) = keys %{$a};
2461 if ($a_key eq $b_key) {
2462 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2467 return ($a eq $b_key) ? 1 : 0;
2470 if (ref $a eq 'HASH') {
2471 my ($a_key) = keys %{$a};
2472 return ($b eq $a_key) ? 1 : 0;
2474 return ($b eq $a) ? 1 : 0;
2480 my ($self, $orig, $import) = @_;
2482 return $import unless defined($orig);
2483 return $orig unless defined($import);
2485 $orig = $self->_rollout_attr($orig);
2486 $import = $self->_rollout_attr($import);
2489 foreach my $import_element ( @{$import} ) {
2490 # find best candidate from $orig to merge $b_element into
2491 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2492 foreach my $orig_element ( @{$orig} ) {
2493 my $score = $self->_calculate_score( $orig_element, $import_element );
2494 if ($score > $best_candidate->{score}) {
2495 $best_candidate->{position} = $position;
2496 $best_candidate->{score} = $score;
2500 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2502 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2503 push( @{$orig}, $import_element );
2505 my $orig_best = $orig->[$best_candidate->{position}];
2506 # merge orig_best and b_element together and replace original with merged
2507 if (ref $orig_best ne 'HASH') {
2508 $orig->[$best_candidate->{position}] = $import_element;
2509 } elsif (ref $import_element eq 'HASH') {
2510 my ($key) = keys %{$orig_best};
2511 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2514 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2524 $self->_source_handle($_[0]->handle);
2526 $self->_source_handle->resolve;
2530 =head2 throw_exception
2532 See L<DBIx::Class::Schema/throw_exception> for details.
2536 sub throw_exception {
2538 if (ref $self && $self->_source_handle->schema) {
2539 $self->_source_handle->schema->throw_exception(@_)
2546 # XXX: FIXME: Attributes docs need clearing up
2550 Attributes are used to refine a ResultSet in various ways when
2551 searching for data. They can be passed to any method which takes an
2552 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2555 These are in no particular order:
2561 =item Value: ( $order_by | \@order_by | \%order_by )
2565 Which column(s) to order the results by. If a single column name, or
2566 an arrayref of names is supplied, the argument is passed through
2567 directly to SQL. The hashref syntax allows for connection-agnostic
2568 specification of ordering direction:
2570 For descending order:
2572 order_by => { -desc => [qw/col1 col2 col3/] }
2574 For explicit ascending order:
2576 order_by => { -asc => 'col' }
2578 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2579 supported, although you are strongly encouraged to use the hashref
2580 syntax as outlined above.
2586 =item Value: \@columns
2590 Shortcut to request a particular set of columns to be retrieved. Each
2591 column spec may be a string (a table column name), or a hash (in which
2592 case the key is the C<as> value, and the value is used as the C<select>
2593 expression). Adds C<me.> onto the start of any column without a C<.> in
2594 it and sets C<select> from that, then auto-populates C<as> from
2595 C<select> as normal. (You may also use the C<cols> attribute, as in
2596 earlier versions of DBIC.)
2602 =item Value: \@columns
2606 Indicates additional columns to be selected from storage. Works the same
2607 as L</columns> but adds columns to the selection. (You may also use the
2608 C<include_columns> attribute, as in earlier versions of DBIC). For
2611 $schema->resultset('CD')->search(undef, {
2612 '+columns' => ['artist.name'],
2616 would return all CDs and include a 'name' column to the information
2617 passed to object inflation. Note that the 'artist' is the name of the
2618 column (or relationship) accessor, and 'name' is the name of the column
2619 accessor in the related table.
2621 =head2 include_columns
2625 =item Value: \@columns
2629 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2635 =item Value: \@select_columns
2639 Indicates which columns should be selected from the storage. You can use
2640 column names, or in the case of RDBMS back ends, function or stored procedure
2643 $rs = $schema->resultset('Employee')->search(undef, {
2646 { count => 'employeeid' },
2651 When you use function/stored procedure names and do not supply an C<as>
2652 attribute, the column names returned are storage-dependent. E.g. MySQL would
2653 return a column named C<count(employeeid)> in the above example.
2659 Indicates additional columns to be selected from storage. Works the same as
2660 L</select> but adds columns to the selection.
2668 Indicates additional column names for those added via L</+select>. See L</as>.
2676 =item Value: \@inflation_names
2680 Indicates column names for object inflation. That is, C<as>
2681 indicates the name that the column can be accessed as via the
2682 C<get_column> method (or via the object accessor, B<if one already
2683 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2685 The C<as> attribute is used in conjunction with C<select>,
2686 usually when C<select> contains one or more function or stored
2689 $rs = $schema->resultset('Employee')->search(undef, {
2692 { count => 'employeeid' }
2694 as => ['name', 'employee_count'],
2697 my $employee = $rs->first(); # get the first Employee
2699 If the object against which the search is performed already has an accessor
2700 matching a column name specified in C<as>, the value can be retrieved using
2701 the accessor as normal:
2703 my $name = $employee->name();
2705 If on the other hand an accessor does not exist in the object, you need to
2706 use C<get_column> instead:
2708 my $employee_count = $employee->get_column('employee_count');
2710 You can create your own accessors if required - see
2711 L<DBIx::Class::Manual::Cookbook> for details.
2713 Please note: This will NOT insert an C<AS employee_count> into the SQL
2714 statement produced, it is used for internal access only. Thus
2715 attempting to use the accessor in an C<order_by> clause or similar
2716 will fail miserably.
2718 To get around this limitation, you can supply literal SQL to your
2719 C<select> attibute that contains the C<AS alias> text, eg:
2721 select => [\'myfield AS alias']
2727 =item Value: ($rel_name | \@rel_names | \%rel_names)
2731 Contains a list of relationships that should be joined for this query. For
2734 # Get CDs by Nine Inch Nails
2735 my $rs = $schema->resultset('CD')->search(
2736 { 'artist.name' => 'Nine Inch Nails' },
2737 { join => 'artist' }
2740 Can also contain a hash reference to refer to the other relation's relations.
2743 package MyApp::Schema::Track;
2744 use base qw/DBIx::Class/;
2745 __PACKAGE__->table('track');
2746 __PACKAGE__->add_columns(qw/trackid cd position title/);
2747 __PACKAGE__->set_primary_key('trackid');
2748 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2751 # In your application
2752 my $rs = $schema->resultset('Artist')->search(
2753 { 'track.title' => 'Teardrop' },
2755 join => { cd => 'track' },
2756 order_by => 'artist.name',
2760 You need to use the relationship (not the table) name in conditions,
2761 because they are aliased as such. The current table is aliased as "me", so
2762 you need to use me.column_name in order to avoid ambiguity. For example:
2764 # Get CDs from 1984 with a 'Foo' track
2765 my $rs = $schema->resultset('CD')->search(
2768 'tracks.name' => 'Foo'
2770 { join => 'tracks' }
2773 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2774 similarly for a third time). For e.g.
2776 my $rs = $schema->resultset('Artist')->search({
2777 'cds.title' => 'Down to Earth',
2778 'cds_2.title' => 'Popular',
2780 join => [ qw/cds cds/ ],
2783 will return a set of all artists that have both a cd with title 'Down
2784 to Earth' and a cd with title 'Popular'.
2786 If you want to fetch related objects from other tables as well, see C<prefetch>
2789 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2795 =item Value: ($rel_name | \@rel_names | \%rel_names)
2799 Contains one or more relationships that should be fetched along with
2800 the main query (when they are accessed afterwards the data will
2801 already be available, without extra queries to the database). This is
2802 useful for when you know you will need the related objects, because it
2803 saves at least one query:
2805 my $rs = $schema->resultset('Tag')->search(
2814 The initial search results in SQL like the following:
2816 SELECT tag.*, cd.*, artist.* FROM tag
2817 JOIN cd ON tag.cd = cd.cdid
2818 JOIN artist ON cd.artist = artist.artistid
2820 L<DBIx::Class> has no need to go back to the database when we access the
2821 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2824 Simple prefetches will be joined automatically, so there is no need
2825 for a C<join> attribute in the above search.
2827 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2828 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2829 with an accessor type of 'single' or 'filter'). A more complex example that
2830 prefetches an artists cds, the tracks on those cds, and the tags associted
2831 with that artist is given below (assuming many-to-many from artists to tags):
2833 my $rs = $schema->resultset('Artist')->search(
2837 { cds => 'tracks' },
2838 { artist_tags => 'tags' }
2844 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2845 attributes will be ignored.
2855 Makes the resultset paged and specifies the page to retrieve. Effectively
2856 identical to creating a non-pages resultset and then calling ->page($page)
2859 If L<rows> attribute is not specified it defualts to 10 rows per page.
2861 When you have a paged resultset, L</count> will only return the number
2862 of rows in the page. To get the total, use the L</pager> and call
2863 C<total_entries> on it.
2873 Specifes the maximum number of rows for direct retrieval or the number of
2874 rows per page if the page attribute or method is used.
2880 =item Value: $offset
2884 Specifies the (zero-based) row number for the first row to be returned, or the
2885 of the first row of the first page if paging is used.
2891 =item Value: \@columns
2895 A arrayref of columns to group by. Can include columns of joined tables.
2897 group_by => [qw/ column1 column2 ... /]
2903 =item Value: $condition
2907 HAVING is a select statement attribute that is applied between GROUP BY and
2908 ORDER BY. It is applied to the after the grouping calculations have been
2911 having => { 'count(employee)' => { '>=', 100 } }
2917 =item Value: (0 | 1)
2921 Set to 1 to group by all columns.
2927 Adds to the WHERE clause.
2929 # only return rows WHERE deleted IS NULL for all searches
2930 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2932 Can be overridden by passing C<{ where => undef }> as an attribute
2939 Set to 1 to cache search results. This prevents extra SQL queries if you
2940 revisit rows in your ResultSet:
2942 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2944 while( my $artist = $resultset->next ) {
2948 $rs->first; # without cache, this would issue a query
2950 By default, searches are not cached.
2952 For more examples of using these attributes, see
2953 L<DBIx::Class::Manual::Cookbook>.
2959 =item Value: \@from_clause
2963 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
2964 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
2967 NOTE: Use this on your own risk. This allows you to shoot off your foot!
2969 C<join> will usually do what you need and it is strongly recommended that you
2970 avoid using C<from> unless you cannot achieve the desired result using C<join>.
2971 And we really do mean "cannot", not just tried and failed. Attempting to use
2972 this because you're having problems with C<join> is like trying to use x86
2973 ASM because you've got a syntax error in your C. Trust us on this.
2975 Now, if you're still really, really sure you need to use this (and if you're
2976 not 100% sure, ask the mailing list first), here's an explanation of how this
2979 The syntax is as follows -
2982 { <alias1> => <table1> },
2984 { <alias2> => <table2>, -join_type => 'inner|left|right' },
2985 [], # nested JOIN (optional)
2986 { <table1.column1> => <table2.column2>, ... (more conditions) },
2988 # More of the above [ ] may follow for additional joins
2995 ON <table1.column1> = <table2.column2>
2996 <more joins may follow>
2998 An easy way to follow the examples below is to remember the following:
3000 Anything inside "[]" is a JOIN
3001 Anything inside "{}" is a condition for the enclosing JOIN
3003 The following examples utilize a "person" table in a family tree application.
3004 In order to express parent->child relationships, this table is self-joined:
3006 # Person->belongs_to('father' => 'Person');
3007 # Person->belongs_to('mother' => 'Person');
3009 C<from> can be used to nest joins. Here we return all children with a father,
3010 then search against all mothers of those children:
3012 $rs = $schema->resultset('Person')->search(
3015 alias => 'mother', # alias columns in accordance with "from"
3017 { mother => 'person' },
3020 { child => 'person' },
3022 { father => 'person' },
3023 { 'father.person_id' => 'child.father_id' }
3026 { 'mother.person_id' => 'child.mother_id' }
3033 # SELECT mother.* FROM person mother
3036 # JOIN person father
3037 # ON ( father.person_id = child.father_id )
3039 # ON ( mother.person_id = child.mother_id )
3041 The type of any join can be controlled manually. To search against only people
3042 with a father in the person table, we could explicitly use C<INNER JOIN>:
3044 $rs = $schema->resultset('Person')->search(
3047 alias => 'child', # alias columns in accordance with "from"
3049 { child => 'person' },
3051 { father => 'person', -join_type => 'inner' },
3052 { 'father.id' => 'child.father_id' }
3059 # SELECT child.* FROM person child
3060 # INNER JOIN person father ON child.father_id = father.id
3062 If you need to express really complex joins or you need a subselect, you
3063 can supply literal SQL to C<from> via a scalar reference. In this case
3064 the contents of the scalar will replace the table name asscoiated with the
3067 WARNING: This technique might very well not work as expected on chained
3068 searches - you have been warned.
3070 # Assuming the Event resultsource is defined as:
3072 MySchema::Event->add_columns (
3075 is_auto_increment => 1,
3084 MySchema::Event->set_primary_key ('sequence');
3086 # This will get back the latest event for every location. The column
3087 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3088 # combo to limit the resultset
3090 $rs = $schema->resultset('Event');
3091 $table = $rs->result_source->name;
3092 $latest = $rs->search (
3095 (SELECT e1.* FROM $table e1
3097 ON e1.location = e2.location
3098 AND e1.sequence < e2.sequence
3099 WHERE e2.sequence is NULL
3104 # Equivalent SQL (with the DBIC chunks added):
3106 SELECT me.sequence, me.location, me.type FROM
3107 (SELECT e1.* FROM events e1
3109 ON e1.location = e2.location
3110 AND e1.sequence < e2.sequence
3111 WHERE e2.sequence is NULL
3118 =item Value: ( 'update' | 'shared' )
3122 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT