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.
282 # Special-case handling for (undef, undef).
283 if ( @_ == 2 && !defined $_[1] && !defined $_[0] ) {
288 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
289 my $our_attrs = { %{$self->{attrs}} };
290 my $having = delete $our_attrs->{having};
291 my $where = delete $our_attrs->{where};
295 my %safe = (alias => 1, cache => 1);
298 (@_ && defined($_[0])) # @_ == () or (undef)
300 (keys %$attrs # empty attrs or only 'safe' attrs
301 && List::Util::first { !$safe{$_} } keys %$attrs)
303 # no search, effectively just a clone
304 $rows = $self->get_cache;
307 my $new_attrs = { %{$our_attrs}, %{$attrs} };
309 # merge new attrs into inherited
310 foreach my $key (qw/join prefetch +select +as bind/) {
311 next unless exists $attrs->{$key};
312 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
317 (@_ == 1 || ref $_[0] eq "HASH")
319 (ref $_[0] eq 'HASH')
321 (keys %{ $_[0] } > 0)
329 ? $self->throw_exception("Odd number of arguments to search")
336 if (defined $where) {
337 $new_attrs->{where} = (
338 defined $new_attrs->{where}
341 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
342 } $where, $new_attrs->{where}
349 $new_attrs->{where} = (
350 defined $new_attrs->{where}
353 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
354 } $cond, $new_attrs->{where}
360 if (defined $having) {
361 $new_attrs->{having} = (
362 defined $new_attrs->{having}
365 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
366 } $having, $new_attrs->{having}
372 my $rs = (ref $self)->new($self->result_source, $new_attrs);
374 $rs->set_cache($rows);
379 =head2 search_literal
383 =item Arguments: $sql_fragment, @bind_values
385 =item Return Value: $resultset (scalar context), @row_objs (list context)
389 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
390 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
392 Pass a literal chunk of SQL to be added to the conditional part of the
395 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
396 only be used in that context. C<search_literal> is a convenience method.
397 It is equivalent to calling $schema->search(\[]), but if you want to ensure
398 columns are bound correctly, use C<search>.
400 Example of how to use C<search> instead of C<search_literal>
402 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
403 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
406 See L<DBIx::Class::Manual::Cookbook/Searching> and
407 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
408 require C<search_literal>.
413 my ($self, $sql, @bind) = @_;
415 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
418 return $self->search(\[ $sql, map [ __DUMMY__ => $_ ], @bind ], ($attr || () ));
425 =item Arguments: @values | \%cols, \%attrs?
427 =item Return Value: $row_object | undef
431 Finds a row based on its primary key or unique constraint. For example, to find
432 a row by its primary key:
434 my $cd = $schema->resultset('CD')->find(5);
436 You can also find a row by a specific unique constraint using the C<key>
437 attribute. For example:
439 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
440 key => 'cd_artist_title'
443 Additionally, you can specify the columns explicitly by name:
445 my $cd = $schema->resultset('CD')->find(
447 artist => 'Massive Attack',
448 title => 'Mezzanine',
450 { key => 'cd_artist_title' }
453 If the C<key> is specified as C<primary>, it searches only on the primary key.
455 If no C<key> is specified, it searches on all unique constraints defined on the
456 source for which column data is provided, including the primary key.
458 If your table does not have a primary key, you B<must> provide a value for the
459 C<key> attribute matching one of the unique constraints on the source.
461 In addition to C<key>, L</find> recognizes and applies standard
462 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
464 Note: If your query does not return only one row, a warning is generated:
466 Query returned more than one row
468 See also L</find_or_create> and L</update_or_create>. For information on how to
469 declare unique constraints, see
470 L<DBIx::Class::ResultSource/add_unique_constraint>.
476 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
478 # Default to the primary key, but allow a specific key
479 my @cols = exists $attrs->{key}
480 ? $self->result_source->unique_constraint_columns($attrs->{key})
481 : $self->result_source->primary_columns;
482 $self->throw_exception(
483 "Can't find unless a primary key is defined or unique constraint is specified"
486 # Parse out a hashref from input
488 if (ref $_[0] eq 'HASH') {
489 $input_query = { %{$_[0]} };
491 elsif (@_ == @cols) {
493 @{$input_query}{@cols} = @_;
496 # Compatibility: Allow e.g. find(id => $value)
497 carp "Find by key => value deprecated; please use a hashref instead";
501 my (%related, $info);
503 KEY: foreach my $key (keys %$input_query) {
504 if (ref($input_query->{$key})
505 && ($info = $self->result_source->relationship_info($key))) {
506 my $val = delete $input_query->{$key};
507 next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
508 my $rel_q = $self->result_source->resolve_condition(
509 $info->{cond}, $val, $key
511 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
512 @related{keys %$rel_q} = values %$rel_q;
515 if (my @keys = keys %related) {
516 @{$input_query}{@keys} = values %related;
520 # Build the final query: Default to the disjunction of the unique queries,
521 # but allow the input query in case the ResultSet defines the query or the
522 # user is abusing find
523 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
525 if (exists $attrs->{key}) {
526 my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key});
527 my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
528 $query = $self->_add_alias($unique_query, $alias);
531 my @unique_queries = $self->_unique_queries($input_query, $attrs);
532 $query = @unique_queries
533 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
534 : $self->_add_alias($input_query, $alias);
539 my $rs = $self->search($query, $attrs);
540 if (keys %{$rs->_resolved_attrs->{collapse}}) {
542 carp "Query returned more than one row" if $rs->next;
550 if (keys %{$self->_resolved_attrs->{collapse}}) {
551 my $rs = $self->search($query);
553 carp "Query returned more than one row" if $rs->next;
557 return $self->single($query);
564 # Add the specified alias to the specified query hash. A copy is made so the
565 # original query is not modified.
568 my ($self, $query, $alias) = @_;
570 my %aliased = %$query;
571 foreach my $col (grep { ! m/\./ } keys %aliased) {
572 $aliased{"$alias.$col"} = delete $aliased{$col};
580 # Build a list of queries which satisfy unique constraints.
582 sub _unique_queries {
583 my ($self, $query, $attrs) = @_;
585 my @constraint_names = exists $attrs->{key}
587 : $self->result_source->unique_constraint_names;
589 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
590 my $num_where = scalar keys %$where;
593 foreach my $name (@constraint_names) {
594 my @unique_cols = $self->result_source->unique_constraint_columns($name);
595 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
597 my $num_cols = scalar @unique_cols;
598 my $num_query = scalar keys %$unique_query;
600 my $total = $num_query + $num_where;
601 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
602 # The query is either unique on its own or is unique in combination with
603 # the existing where clause
604 push @unique_queries, $unique_query;
608 return @unique_queries;
611 # _build_unique_query
613 # Constrain the specified query hash based on the specified column names.
615 sub _build_unique_query {
616 my ($self, $query, $unique_cols) = @_;
619 map { $_ => $query->{$_} }
620 grep { exists $query->{$_} }
625 =head2 search_related
629 =item Arguments: $rel, $cond, \%attrs?
631 =item Return Value: $new_resultset
635 $new_rs = $cd_rs->search_related('artist', {
639 Searches the specified relationship, optionally specifying a condition and
640 attributes for matching records. See L</ATTRIBUTES> for more information.
645 return shift->related_resultset(shift)->search(@_);
648 =head2 search_related_rs
650 This method works exactly the same as search_related, except that
651 it guarantees a restultset, even in list context.
655 sub search_related_rs {
656 return shift->related_resultset(shift)->search_rs(@_);
663 =item Arguments: none
665 =item Return Value: $cursor
669 Returns a storage-driven cursor to the given resultset. See
670 L<DBIx::Class::Cursor> for more information.
677 my $attrs = { %{$self->_resolved_attrs} };
678 return $self->{cursor}
679 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
680 $attrs->{where},$attrs);
687 =item Arguments: $cond?
689 =item Return Value: $row_object?
693 my $cd = $schema->resultset('CD')->single({ year => 2001 });
695 Inflates the first result without creating a cursor if the resultset has
696 any records in it; if not returns nothing. Used by L</find> as a lean version of
699 While this method can take an optional search condition (just like L</search>)
700 being a fast-code-path it does not recognize search attributes. If you need to
701 add extra joins or similar, call L</search> and then chain-call L</single> on the
702 L<DBIx::Class::ResultSet> returned.
708 As of 0.08100, this method enforces the assumption that the preceeding
709 query returns only one row. If more than one row is returned, you will receive
712 Query returned more than one row
714 In this case, you should be using L</first> or L</find> instead, or if you really
715 know what you are doing, use the L</rows> attribute to explicitly limit the size
723 my ($self, $where) = @_;
725 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
728 my $attrs = { %{$self->_resolved_attrs} };
730 if (defined $attrs->{where}) {
733 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
734 $where, delete $attrs->{where} ]
737 $attrs->{where} = $where;
741 # XXX: Disabled since it doesn't infer uniqueness in all cases
742 # unless ($self->_is_unique_query($attrs->{where})) {
743 # carp "Query not guaranteed to return a single row"
744 # . "; please declare your unique constraints or use search instead";
747 my @data = $self->result_source->storage->select_single(
748 $attrs->{from}, $attrs->{select},
749 $attrs->{where}, $attrs
752 return (@data ? ($self->_construct_object(@data))[0] : undef);
757 # Try to determine if the specified query is guaranteed to be unique, based on
758 # the declared unique constraints.
760 sub _is_unique_query {
761 my ($self, $query) = @_;
763 my $collapsed = $self->_collapse_query($query);
764 my $alias = $self->{attrs}{alias};
766 foreach my $name ($self->result_source->unique_constraint_names) {
767 my @unique_cols = map {
769 } $self->result_source->unique_constraint_columns($name);
771 # Count the values for each unique column
772 my %seen = map { $_ => 0 } @unique_cols;
774 foreach my $key (keys %$collapsed) {
775 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
776 next unless exists $seen{$aliased}; # Additional constraints are okay
777 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
780 # If we get 0 or more than 1 value for a column, it's not necessarily unique
781 return 1 unless grep { $_ != 1 } values %seen;
789 # Recursively collapse the query, accumulating values for each column.
791 sub _collapse_query {
792 my ($self, $query, $collapsed) = @_;
796 if (ref $query eq 'ARRAY') {
797 foreach my $subquery (@$query) {
798 next unless ref $subquery; # -or
799 # warn "ARRAY: " . Dumper $subquery;
800 $collapsed = $self->_collapse_query($subquery, $collapsed);
803 elsif (ref $query eq 'HASH') {
804 if (keys %$query and (keys %$query)[0] eq '-and') {
805 foreach my $subquery (@{$query->{-and}}) {
806 # warn "HASH: " . Dumper $subquery;
807 $collapsed = $self->_collapse_query($subquery, $collapsed);
811 # warn "LEAF: " . Dumper $query;
812 foreach my $col (keys %$query) {
813 my $value = $query->{$col};
814 $collapsed->{$col}{$value}++;
826 =item Arguments: $cond?
828 =item Return Value: $resultsetcolumn
832 my $max_length = $rs->get_column('length')->max;
834 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
839 my ($self, $column) = @_;
840 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
848 =item Arguments: $cond, \%attrs?
850 =item Return Value: $resultset (scalar context), @row_objs (list context)
854 # WHERE title LIKE '%blue%'
855 $cd_rs = $rs->search_like({ title => '%blue%'});
857 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
858 that this is simply a convenience method retained for ex Class::DBI users.
859 You most likely want to use L</search> with specific operators.
861 For more information, see L<DBIx::Class::Manual::Cookbook>.
863 This method is deprecated and will be removed in 0.09. Use L</search()>
864 instead. An example conversion is:
866 ->search_like({ foo => 'bar' });
870 ->search({ foo => { like => 'bar' } });
877 'search_like() is deprecated and will be removed in 0.09.',
878 'Instead use ->search({ x => { -like => "y%" } })',
879 '(note the outer pair of {}s - they are important!)'
881 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
882 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
883 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
884 return $class->search($query, { %$attrs });
891 =item Arguments: $first, $last
893 =item Return Value: $resultset (scalar context), @row_objs (list context)
897 Returns a resultset or object list representing a subset of elements from the
898 resultset slice is called on. Indexes are from 0, i.e., to get the first
901 my ($one, $two, $three) = $rs->slice(0, 2);
906 my ($self, $min, $max) = @_;
907 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
908 $attrs->{offset} = $self->{attrs}{offset} || 0;
909 $attrs->{offset} += $min;
910 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
911 return $self->search(undef(), $attrs);
912 #my $slice = (ref $self)->new($self->result_source, $attrs);
913 #return (wantarray ? $slice->all : $slice);
920 =item Arguments: none
922 =item Return Value: $result?
926 Returns the next element in the resultset (C<undef> is there is none).
928 Can be used to efficiently iterate over records in the resultset:
930 my $rs = $schema->resultset('CD')->search;
931 while (my $cd = $rs->next) {
935 Note that you need to store the resultset object, and call C<next> on it.
936 Calling C<< resultset('Table')->next >> repeatedly will always return the
937 first record from the resultset.
943 if (my $cache = $self->get_cache) {
944 $self->{all_cache_position} ||= 0;
945 return $cache->[$self->{all_cache_position}++];
947 if ($self->{attrs}{cache}) {
948 $self->{all_cache_position} = 1;
949 return ($self->all)[0];
951 if ($self->{stashed_objects}) {
952 my $obj = shift(@{$self->{stashed_objects}});
953 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
957 exists $self->{stashed_row}
958 ? @{delete $self->{stashed_row}}
959 : $self->cursor->next
961 return undef unless (@row);
962 my ($row, @more) = $self->_construct_object(@row);
963 $self->{stashed_objects} = \@more if @more;
967 sub _construct_object {
968 my ($self, @row) = @_;
969 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
970 my @new = $self->result_class->inflate_result($self->result_source, @$info);
971 @new = $self->{_attrs}{record_filter}->(@new)
972 if exists $self->{_attrs}{record_filter};
976 sub _collapse_result {
977 my ($self, $as_proto, $row) = @_;
981 # 'foo' => [ undef, 'foo' ]
982 # 'foo.bar' => [ 'foo', 'bar' ]
983 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
985 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
987 my %collapse = %{$self->{_attrs}{collapse}||{}};
991 # if we're doing collapsing (has_many prefetch) we need to grab records
992 # until the PK changes, so fill @pri_index. if not, we leave it empty so
993 # we know we don't have to bother.
995 # the reason for not using the collapse stuff directly is because if you
996 # had for e.g. two artists in a row with no cds, the collapse info for
997 # both would be NULL (undef) so you'd lose the second artist
999 # store just the index so we can check the array positions from the row
1000 # without having to contruct the full hash
1002 if (keys %collapse) {
1003 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1004 foreach my $i (0 .. $#construct_as) {
1005 next if defined($construct_as[$i][0]); # only self table
1006 if (delete $pri{$construct_as[$i][1]}) {
1007 push(@pri_index, $i);
1009 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1013 # no need to do an if, it'll be empty if @pri_index is empty anyway
1015 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1019 do { # no need to check anything at the front, we always want the first row
1023 foreach my $this_as (@construct_as) {
1024 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1027 push(@const_rows, \%const);
1029 } until ( # no pri_index => no collapse => drop straight out
1032 do { # get another row, stash it, drop out if different PK
1034 @copy = $self->cursor->next;
1035 $self->{stashed_row} = \@copy;
1037 # last thing in do block, counts as true if anything doesn't match
1039 # check xor defined first for NULL vs. NOT NULL then if one is
1040 # defined the other must be so check string equality
1043 (defined $pri_vals{$_} ^ defined $copy[$_])
1044 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1049 my $alias = $self->{attrs}{alias};
1056 foreach my $const (@const_rows) {
1057 scalar @const_keys or do {
1058 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1060 foreach my $key (@const_keys) {
1063 my @parts = split(/\./, $key);
1065 my $data = $const->{$key};
1066 foreach my $p (@parts) {
1067 $target = $target->[1]->{$p} ||= [];
1069 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1070 # collapsing at this point and on final part
1071 my $pos = $collapse_pos{$cur};
1072 CK: foreach my $ck (@ckey) {
1073 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1074 $collapse_pos{$cur} = $data;
1075 delete @collapse_pos{ # clear all positioning for sub-entries
1076 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1083 if (exists $collapse{$cur}) {
1084 $target = $target->[-1];
1087 $target->[0] = $data;
1089 $info->[0] = $const->{$key};
1097 =head2 result_source
1101 =item Arguments: $result_source?
1103 =item Return Value: $result_source
1107 An accessor for the primary ResultSource object from which this ResultSet
1114 =item Arguments: $result_class?
1116 =item Return Value: $result_class
1120 An accessor for the class to use when creating row objects. Defaults to
1121 C<< result_source->result_class >> - which in most cases is the name of the
1122 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1124 Note that changing the result_class will also remove any components
1125 that were originally loaded in the source class via
1126 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1127 in the original source class will not run.
1132 my ($self, $result_class) = @_;
1133 if ($result_class) {
1134 $self->ensure_class_loaded($result_class);
1135 $self->_result_class($result_class);
1137 $self->_result_class;
1144 =item Arguments: $cond, \%attrs??
1146 =item Return Value: $count
1150 Performs an SQL C<COUNT> with the same query as the resultset was built
1151 with to find the number of elements. If passed arguments, does a search
1152 on the resultset and counts the results of that.
1158 return $self->search(@_)->count if @_ and defined $_[0];
1159 return scalar @{ $self->get_cache } if $self->get_cache;
1160 my $count = $self->_count;
1161 return 0 unless $count;
1163 # need to take offset from resolved attrs
1165 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1166 $count = $self->{attrs}{rows} if
1167 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1168 $count = 0 if ($count < 0);
1172 sub _count { # Separated out so pager can get the full count
1174 my $attrs = { %{$self->_resolved_attrs} };
1176 if (my $group_by = $attrs->{group_by}) {
1177 delete $attrs->{order_by};
1179 $attrs->{select} = $group_by;
1180 $attrs->{from} = [ { 'mesub' => (ref $self)->new($self->result_source, $attrs)->cursor->as_query } ];
1181 delete $attrs->{where};
1184 $attrs->{select} = { count => '*' };
1185 $attrs->{as} = [qw/count/];
1187 # offset, order by, group by, where and page are not needed to count. record_filter is cdbi
1188 delete $attrs->{$_} for qw/rows offset order_by group_by page pager record_filter/;
1190 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1191 my ($count) = $tmp_rs->cursor->next;
1199 =head2 count_literal
1203 =item Arguments: $sql_fragment, @bind_values
1205 =item Return Value: $count
1209 Counts the results in a literal query. Equivalent to calling L</search_literal>
1210 with the passed arguments, then L</count>.
1214 sub count_literal { shift->search_literal(@_)->count; }
1220 =item Arguments: none
1222 =item Return Value: @objects
1226 Returns all elements in the resultset. Called implicitly if the resultset
1227 is returned in list context.
1234 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1237 return @{ $self->get_cache } if $self->get_cache;
1241 # TODO: don't call resolve here
1242 if (keys %{$self->_resolved_attrs->{collapse}}) {
1243 # if ($self->{attrs}{prefetch}) {
1244 # Using $self->cursor->all is really just an optimisation.
1245 # If we're collapsing has_many prefetches it probably makes
1246 # very little difference, and this is cleaner than hacking
1247 # _construct_object to survive the approach
1248 my @row = $self->cursor->next;
1250 push(@obj, $self->_construct_object(@row));
1251 @row = (exists $self->{stashed_row}
1252 ? @{delete $self->{stashed_row}}
1253 : $self->cursor->next);
1256 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1259 $self->set_cache(\@obj) if $self->{attrs}{cache};
1267 =item Arguments: none
1269 =item Return Value: $self
1273 Resets the resultset's cursor, so you can iterate through the elements again.
1279 delete $self->{_attrs} if exists $self->{_attrs};
1280 $self->{all_cache_position} = 0;
1281 $self->cursor->reset;
1289 =item Arguments: none
1291 =item Return Value: $object?
1295 Resets the resultset and returns an object for the first result (if the
1296 resultset returns anything).
1301 return $_[0]->reset->next;
1304 # _cond_for_update_delete
1306 # update/delete require the condition to be modified to handle
1307 # the differing SQL syntax available. This transforms the $self->{cond}
1308 # appropriately, returning the new condition.
1310 sub _cond_for_update_delete {
1311 my ($self, $full_cond) = @_;
1314 $full_cond ||= $self->{cond};
1315 # No-op. No condition, we're updating/deleting everything
1316 return $cond unless ref $full_cond;
1318 foreach my $pk ($self->result_source->primary_columns) {
1319 $cond->{$pk} = { -in => $self->get_column($pk)->as_query };
1330 =item Arguments: \%values
1332 =item Return Value: $storage_rv
1336 Sets the specified columns in the resultset to the supplied values in a
1337 single query. Return value will be true if the update succeeded or false
1338 if no records were updated; exact type of success value is storage-dependent.
1343 my ($self, $values) = @_;
1344 $self->throw_exception("Values for update must be a hash")
1345 unless ref $values eq 'HASH';
1347 my $cond = $self->_cond_for_update_delete;
1349 return $self->result_source->storage->update(
1350 $self->result_source, $values, $cond
1358 =item Arguments: \%values
1360 =item Return Value: 1
1364 Fetches all objects and updates them one at a time. Note that C<update_all>
1365 will run DBIC cascade triggers, while L</update> will not.
1370 my ($self, $values) = @_;
1371 $self->throw_exception("Values for update must be a hash")
1372 unless ref $values eq 'HASH';
1373 foreach my $obj ($self->all) {
1374 $obj->set_columns($values)->update;
1383 =item Arguments: none
1385 =item Return Value: 1
1389 Deletes the contents of the resultset from its result source. Note that this
1390 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1391 to run. See also L<DBIx::Class::Row/delete>.
1393 delete may not generate correct SQL for a query with joins or a resultset
1394 chained from a related resultset. In this case it will generate a warning:-
1396 In these cases you may find that delete_all is more appropriate, or you
1397 need to respecify your query in a way that can be expressed without a join.
1403 $self->throw_exception("Delete should not be passed any arguments")
1406 my $cond = $self->_cond_for_update_delete;
1408 $self->result_source->storage->delete($self->result_source, $cond);
1416 =item Arguments: none
1418 =item Return Value: 1
1422 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1423 will run DBIC cascade triggers, while L</delete> will not.
1429 $_->delete for $self->all;
1437 =item Arguments: \@data;
1441 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1442 For the arrayref of hashrefs style each hashref should be a structure suitable
1443 forsubmitting to a $resultset->create(...) method.
1445 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1446 to insert the data, as this is a faster method.
1448 Otherwise, each set of data is inserted into the database using
1449 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1450 objects is returned.
1452 Example: Assuming an Artist Class that has many CDs Classes relating:
1454 my $Artist_rs = $schema->resultset("Artist");
1456 ## Void Context Example
1457 $Artist_rs->populate([
1458 { artistid => 4, name => 'Manufactured Crap', cds => [
1459 { title => 'My First CD', year => 2006 },
1460 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1463 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1464 { title => 'My parents sold me to a record company' ,year => 2005 },
1465 { title => 'Why Am I So Ugly?', year => 2006 },
1466 { title => 'I Got Surgery and am now Popular', year => 2007 }
1471 ## Array Context Example
1472 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1473 { name => "Artist One"},
1474 { name => "Artist Two"},
1475 { name => "Artist Three", cds=> [
1476 { title => "First CD", year => 2007},
1477 { title => "Second CD", year => 2008},
1481 print $ArtistOne->name; ## response is 'Artist One'
1482 print $ArtistThree->cds->count ## reponse is '2'
1484 For the arrayref of arrayrefs style, the first element should be a list of the
1485 fieldsnames to which the remaining elements are rows being inserted. For
1488 $Arstist_rs->populate([
1489 [qw/artistid name/],
1490 [100, 'A Formally Unknown Singer'],
1491 [101, 'A singer that jumped the shark two albums ago'],
1492 [102, 'An actually cool singer.'],
1495 Please note an important effect on your data when choosing between void and
1496 wantarray context. Since void context goes straight to C<insert_bulk> in
1497 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1498 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1499 create primary keys for you, you will find that your PKs are empty. In this
1500 case you will have to use the wantarray context in order to create those
1506 my $self = shift @_;
1507 my $data = ref $_[0][0] eq 'HASH'
1508 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1509 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1511 if(defined wantarray) {
1513 foreach my $item (@$data) {
1514 push(@created, $self->create($item));
1518 my ($first, @rest) = @$data;
1520 my @names = grep {!ref $first->{$_}} keys %$first;
1521 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1522 my @pks = $self->result_source->primary_columns;
1524 ## do the belongs_to relationships
1525 foreach my $index (0..$#$data) {
1526 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1527 my @ret = $self->populate($data);
1531 foreach my $rel (@rels) {
1532 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1533 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1534 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1535 my $related = $result->result_source->resolve_condition(
1536 $result->result_source->relationship_info($reverse)->{cond},
1541 delete $data->[$index]->{$rel};
1542 $data->[$index] = {%{$data->[$index]}, %$related};
1544 push @names, keys %$related if $index == 0;
1548 ## do bulk insert on current row
1549 my @values = map { [ @$_{@names} ] } @$data;
1551 $self->result_source->storage->insert_bulk(
1552 $self->result_source,
1557 ## do the has_many relationships
1558 foreach my $item (@$data) {
1560 foreach my $rel (@rels) {
1561 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1563 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1564 || $self->throw_exception('Cannot find the relating object.');
1566 my $child = $parent->$rel;
1568 my $related = $child->result_source->resolve_condition(
1569 $parent->result_source->relationship_info($rel)->{cond},
1574 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1575 my @populate = map { {%$_, %$related} } @rows_to_add;
1577 $child->populate( \@populate );
1583 =head2 _normalize_populate_args ($args)
1585 Private method used by L</populate> to normalize its incoming arguments. Factored
1586 out in case you want to subclass and accept new argument structures to the
1587 L</populate> method.
1591 sub _normalize_populate_args {
1592 my ($self, $data) = @_;
1593 my @names = @{shift(@$data)};
1594 my @results_to_create;
1595 foreach my $datum (@$data) {
1596 my %result_to_create;
1597 foreach my $index (0..$#names) {
1598 $result_to_create{$names[$index]} = $$datum[$index];
1600 push @results_to_create, \%result_to_create;
1602 return \@results_to_create;
1609 =item Arguments: none
1611 =item Return Value: $pager
1615 Return Value a L<Data::Page> object for the current resultset. Only makes
1616 sense for queries with a C<page> attribute.
1618 To get the full count of entries for a paged resultset, call
1619 C<total_entries> on the L<Data::Page> object.
1625 my $attrs = $self->{attrs};
1626 $self->throw_exception("Can't create pager for non-paged rs")
1627 unless $self->{attrs}{page};
1628 $attrs->{rows} ||= 10;
1629 return $self->{pager} ||= Data::Page->new(
1630 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1637 =item Arguments: $page_number
1639 =item Return Value: $rs
1643 Returns a resultset for the $page_number page of the resultset on which page
1644 is called, where each page contains a number of rows equal to the 'rows'
1645 attribute set on the resultset (10 by default).
1650 my ($self, $page) = @_;
1651 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1658 =item Arguments: \%vals
1660 =item Return Value: $rowobject
1664 Creates a new row object in the resultset's result class and returns
1665 it. The row is not inserted into the database at this point, call
1666 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1667 will tell you whether the row object has been inserted or not.
1669 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1674 my ($self, $values) = @_;
1675 $self->throw_exception( "new_result needs a hash" )
1676 unless (ref $values eq 'HASH');
1679 my $alias = $self->{attrs}{alias};
1682 defined $self->{cond}
1683 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1685 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1686 $new{-from_resultset} = [ keys %new ] if keys %new;
1688 $self->throw_exception(
1689 "Can't abstract implicit construct, condition not a hash"
1690 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1692 my $collapsed_cond = (
1694 ? $self->_collapse_cond($self->{cond})
1698 # precendence must be given to passed values over values inherited from
1699 # the cond, so the order here is important.
1700 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1701 while( my($col,$value) = each %implied ){
1702 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1703 $new{$col} = $value->{'='};
1706 $new{$col} = $value if $self->_is_deterministic_value($value);
1712 %{ $self->_remove_alias($values, $alias) },
1713 -source_handle => $self->_source_handle,
1714 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1717 return $self->result_class->new(\%new);
1720 # _is_deterministic_value
1722 # Make an effor to strip non-deterministic values from the condition,
1723 # to make sure new_result chokes less
1725 sub _is_deterministic_value {
1728 my $ref_type = ref $value;
1729 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1730 return 1 if Scalar::Util::blessed($value);
1736 # Recursively collapse the condition.
1738 sub _collapse_cond {
1739 my ($self, $cond, $collapsed) = @_;
1743 if (ref $cond eq 'ARRAY') {
1744 foreach my $subcond (@$cond) {
1745 next unless ref $subcond; # -or
1746 # warn "ARRAY: " . Dumper $subcond;
1747 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1750 elsif (ref $cond eq 'HASH') {
1751 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1752 foreach my $subcond (@{$cond->{-and}}) {
1753 # warn "HASH: " . Dumper $subcond;
1754 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1758 # warn "LEAF: " . Dumper $cond;
1759 foreach my $col (keys %$cond) {
1760 my $value = $cond->{$col};
1761 $collapsed->{$col} = $value;
1771 # Remove the specified alias from the specified query hash. A copy is made so
1772 # the original query is not modified.
1775 my ($self, $query, $alias) = @_;
1777 my %orig = %{ $query || {} };
1780 foreach my $key (keys %orig) {
1782 $unaliased{$key} = $orig{$key};
1785 $unaliased{$1} = $orig{$key}
1786 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1792 =head2 as_query (EXPERIMENTAL)
1796 =item Arguments: none
1798 =item Return Value: \[ $sql, @bind ]
1802 Returns the SQL query and bind vars associated with the invocant.
1804 This is generally used as the RHS for a subquery.
1806 B<NOTE>: This feature is still experimental.
1810 sub as_query { return shift->cursor->as_query(@_) }
1816 =item Arguments: \%vals, \%attrs?
1818 =item Return Value: $rowobject
1822 my $artist = $schema->resultset('Artist')->find_or_new(
1823 { artist => 'fred' }, { key => 'artists' });
1825 $cd->cd_to_producer->find_or_new({ producer => $producer },
1826 { key => 'primary });
1828 Find an existing record from this resultset, based on its primary
1829 key, or a unique constraint. If none exists, instantiate a new result
1830 object and return it. The object will not be saved into your storage
1831 until you call L<DBIx::Class::Row/insert> on it.
1833 You most likely want this method when looking for existing rows using
1834 a unique constraint that is not the primary key, or looking for
1837 If you want objects to be saved immediately, use L</find_or_create> instead.
1839 B<Note>: C<find_or_new> is probably not what you want when creating a
1840 new row in a table that uses primary keys supplied by the
1841 database. Passing in a primary key column with a value of I<undef>
1842 will cause L</find> to attempt to search for a row with a value of
1849 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1850 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1851 my $exists = $self->find($hash, $attrs);
1852 return defined $exists ? $exists : $self->new_result($hash);
1859 =item Arguments: \%vals
1861 =item Return Value: a L<DBIx::Class::Row> $object
1865 Attempt to create a single new row or a row with multiple related rows
1866 in the table represented by the resultset (and related tables). This
1867 will not check for duplicate rows before inserting, use
1868 L</find_or_create> to do that.
1870 To create one row for this resultset, pass a hashref of key/value
1871 pairs representing the columns of the table and the values you wish to
1872 store. If the appropriate relationships are set up, foreign key fields
1873 can also be passed an object representing the foreign row, and the
1874 value will be set to its primary key.
1876 To create related objects, pass a hashref for the value if the related
1877 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1878 and use the name of the relationship as the key. (NOT the name of the field,
1879 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1880 of hashrefs containing the data for each of the rows to create in the foreign
1881 tables, again using the relationship name as the key.
1883 Instead of hashrefs of plain related data (key/value pairs), you may
1884 also pass new or inserted objects. New objects (not inserted yet, see
1885 L</new>), will be inserted into their appropriate tables.
1887 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1889 Example of creating a new row.
1891 $person_rs->create({
1892 name=>"Some Person",
1893 email=>"somebody@someplace.com"
1896 Example of creating a new row and also creating rows in a related C<has_many>
1897 or C<has_one> resultset. Note Arrayref.
1900 { artistid => 4, name => 'Manufactured Crap', cds => [
1901 { title => 'My First CD', year => 2006 },
1902 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1907 Example of creating a new row and also creating a row in a related
1908 C<belongs_to>resultset. Note Hashref.
1911 title=>"Music for Silly Walks",
1914 name=>"Silly Musician",
1921 my ($self, $attrs) = @_;
1922 $self->throw_exception( "create needs a hashref" )
1923 unless ref $attrs eq 'HASH';
1924 return $self->new_result($attrs)->insert;
1927 =head2 find_or_create
1931 =item Arguments: \%vals, \%attrs?
1933 =item Return Value: $rowobject
1937 $cd->cd_to_producer->find_or_create({ producer => $producer },
1938 { key => 'primary });
1940 Tries to find a record based on its primary key or unique constraints; if none
1941 is found, creates one and returns that instead.
1943 my $cd = $schema->resultset('CD')->find_or_create({
1945 artist => 'Massive Attack',
1946 title => 'Mezzanine',
1950 Also takes an optional C<key> attribute, to search by a specific key or unique
1951 constraint. For example:
1953 my $cd = $schema->resultset('CD')->find_or_create(
1955 artist => 'Massive Attack',
1956 title => 'Mezzanine',
1958 { key => 'cd_artist_title' }
1961 B<Note>: Because find_or_create() reads from the database and then
1962 possibly inserts based on the result, this method is subject to a race
1963 condition. Another process could create a record in the table after
1964 the find has completed and before the create has started. To avoid
1965 this problem, use find_or_create() inside a transaction.
1967 B<Note>: C<find_or_create> is probably not what you want when creating
1968 a new row in a table that uses primary keys supplied by the
1969 database. Passing in a primary key column with a value of I<undef>
1970 will cause L</find> to attempt to search for a row with a value of
1973 See also L</find> and L</update_or_create>. For information on how to declare
1974 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1978 sub find_or_create {
1980 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1981 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1982 my $exists = $self->find($hash, $attrs);
1983 return defined $exists ? $exists : $self->create($hash);
1986 =head2 update_or_create
1990 =item Arguments: \%col_values, { key => $unique_constraint }?
1992 =item Return Value: $rowobject
1996 $resultset->update_or_create({ col => $val, ... });
1998 First, searches for an existing row matching one of the unique constraints
1999 (including the primary key) on the source of this resultset. If a row is
2000 found, updates it with the other given column values. Otherwise, creates a new
2003 Takes an optional C<key> attribute to search on a specific unique constraint.
2006 # In your application
2007 my $cd = $schema->resultset('CD')->update_or_create(
2009 artist => 'Massive Attack',
2010 title => 'Mezzanine',
2013 { key => 'cd_artist_title' }
2016 $cd->cd_to_producer->update_or_create({
2017 producer => $producer,
2024 If no C<key> is specified, it searches on all unique constraints defined on the
2025 source, including the primary key.
2027 If the C<key> is specified as C<primary>, it searches only on the primary key.
2029 See also L</find> and L</find_or_create>. For information on how to declare
2030 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2032 B<Note>: C<update_or_create> is probably not what you want when
2033 looking for a row in a table that uses primary keys supplied by the
2034 database, unless you actually have a key value. Passing in a primary
2035 key column with a value of I<undef> will cause L</find> to attempt to
2036 search for a row with a value of I<NULL>.
2040 sub update_or_create {
2042 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2043 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2045 my $row = $self->find($cond, $attrs);
2047 $row->update($cond);
2051 return $self->create($cond);
2054 =head2 update_or_new
2058 =item Arguments: \%col_values, { key => $unique_constraint }?
2060 =item Return Value: $rowobject
2064 $resultset->update_or_new({ col => $val, ... });
2066 First, searches for an existing row matching one of the unique constraints
2067 (including the primary key) on the source of this resultset. If a row is
2068 found, updates it with the other given column values. Otherwise, instantiate
2069 a new result object and return it. The object will not be saved into your storage
2070 until you call L<DBIx::Class::Row/insert> on it.
2072 Takes an optional C<key> attribute to search on a specific unique constraint.
2075 # In your application
2076 my $cd = $schema->resultset('CD')->update_or_new(
2078 artist => 'Massive Attack',
2079 title => 'Mezzanine',
2082 { key => 'cd_artist_title' }
2085 if ($cd->in_storage) {
2086 # the cd was updated
2089 # the cd is not yet in the database, let's insert it
2093 See also L</find>, L</find_or_create> and L<find_or_new>.
2099 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2100 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2102 my $row = $self->find( $cond, $attrs );
2103 if ( defined $row ) {
2104 $row->update($cond);
2108 return $self->new_result($cond);
2115 =item Arguments: none
2117 =item Return Value: \@cache_objects?
2121 Gets the contents of the cache for the resultset, if the cache is set.
2123 The cache is populated either by using the L</prefetch> attribute to
2124 L</search> or by calling L</set_cache>.
2136 =item Arguments: \@cache_objects
2138 =item Return Value: \@cache_objects
2142 Sets the contents of the cache for the resultset. Expects an arrayref
2143 of objects of the same class as those produced by the resultset. Note that
2144 if the cache is set the resultset will return the cached objects rather
2145 than re-querying the database even if the cache attr is not set.
2147 The contents of the cache can also be populated by using the
2148 L</prefetch> attribute to L</search>.
2153 my ( $self, $data ) = @_;
2154 $self->throw_exception("set_cache requires an arrayref")
2155 if defined($data) && (ref $data ne 'ARRAY');
2156 $self->{all_cache} = $data;
2163 =item Arguments: none
2165 =item Return Value: []
2169 Clears the cache for the resultset.
2174 shift->set_cache(undef);
2177 =head2 related_resultset
2181 =item Arguments: $relationship_name
2183 =item Return Value: $resultset
2187 Returns a related resultset for the supplied relationship name.
2189 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2193 sub related_resultset {
2194 my ($self, $rel) = @_;
2196 $self->{related_resultsets} ||= {};
2197 return $self->{related_resultsets}{$rel} ||= do {
2198 my $rel_obj = $self->result_source->relationship_info($rel);
2200 $self->throw_exception(
2201 "search_related: result source '" . $self->result_source->source_name .
2202 "' has no such relationship $rel")
2205 my ($from,$seen) = $self->_resolve_from($rel);
2207 my $join_count = $seen->{$rel};
2208 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2210 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2211 my %attrs = %{$self->{attrs}||{}};
2212 delete @attrs{qw(result_class alias)};
2216 if (my $cache = $self->get_cache) {
2217 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2218 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2223 my $rel_source = $self->result_source->related_source($rel);
2227 # The reason we do this now instead of passing the alias to the
2228 # search_rs below is that if you wrap/overload resultset on the
2229 # source you need to know what alias it's -going- to have for things
2230 # to work sanely (e.g. RestrictWithObject wants to be able to add
2231 # extra query restrictions, and these may need to be $alias.)
2233 my $attrs = $rel_source->resultset_attributes;
2234 local $attrs->{alias} = $alias;
2236 $rel_source->resultset
2244 where => $self->{cond},
2249 $new->set_cache($new_cache) if $new_cache;
2254 =head2 current_source_alias
2258 =item Arguments: none
2260 =item Return Value: $source_alias
2264 Returns the current table alias for the result source this resultset is built
2265 on, that will be used in the SQL query. Usually it is C<me>.
2267 Currently the source alias that refers to the result set returned by a
2268 L</search>/L</find> family method depends on how you got to the resultset: it's
2269 C<me> by default, but eg. L</search_related> aliases it to the related result
2270 source name (and keeps C<me> referring to the original result set). The long
2271 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2272 (and make this method unnecessary).
2274 Thus it's currently necessary to use this method in predefined queries (see
2275 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2276 source alias of the current result set:
2278 # in a result set class
2280 my ($self, $user) = @_;
2282 my $me = $self->current_source_alias;
2284 return $self->search(
2285 "$me.modified" => $user->id,
2291 sub current_source_alias {
2294 return ($self->{attrs} || {})->{alias} || 'me';
2298 my ($self, $extra_join) = @_;
2299 my $source = $self->result_source;
2300 my $attrs = $self->{attrs};
2302 my $from = $attrs->{from}
2303 || [ { $attrs->{alias} => $source->from } ];
2305 my $seen = { %{$attrs->{seen_join}||{}} };
2307 my $join = ($attrs->{join}
2308 ? [ $attrs->{join}, $extra_join ]
2311 # we need to take the prefetch the attrs into account before we
2312 # ->resolve_join as otherwise they get lost - captainL
2313 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2317 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2320 return ($from,$seen);
2323 sub _resolved_attrs {
2325 return $self->{_attrs} if $self->{_attrs};
2327 my $attrs = { %{ $self->{attrs} || {} } };
2328 my $source = $self->result_source;
2329 my $alias = $attrs->{alias};
2331 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2334 # build columns (as long as select isn't set) into a set of as/select hashes
2335 unless ( $attrs->{select} ) {
2337 ( ref($_) eq 'HASH' )
2341 /^\Q${alias}.\E(.+)$/
2352 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2354 # add the additional columns on
2355 foreach ( 'include_columns', '+columns' ) {
2356 push @colbits, map {
2357 ( ref($_) eq 'HASH' )
2359 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2360 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2363 # start with initial select items
2364 if ( $attrs->{select} ) {
2366 ( ref $attrs->{select} eq 'ARRAY' )
2367 ? [ @{ $attrs->{select} } ]
2368 : [ $attrs->{select} ];
2372 ref $attrs->{as} eq 'ARRAY'
2373 ? [ @{ $attrs->{as} } ]
2376 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2381 # otherwise we intialise select & as to empty
2382 $attrs->{select} = [];
2386 # now add colbits to select/as
2387 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2388 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2391 if ( $adds = delete $attrs->{'+select'} ) {
2392 $adds = [$adds] unless ref $adds eq 'ARRAY';
2394 @{ $attrs->{select} },
2395 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2398 if ( $adds = delete $attrs->{'+as'} ) {
2399 $adds = [$adds] unless ref $adds eq 'ARRAY';
2400 push( @{ $attrs->{as} }, @$adds );
2403 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2405 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2406 my $join = delete $attrs->{join} || {};
2408 if ( defined $attrs->{prefetch} ) {
2409 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2413 $attrs->{from} = # have to copy here to avoid corrupting the original
2415 @{ $attrs->{from} },
2416 $source->resolve_join(
2417 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2423 $attrs->{group_by} ||= $attrs->{select}
2424 if delete $attrs->{distinct};
2425 if ( $attrs->{order_by} ) {
2426 $attrs->{order_by} = (
2427 ref( $attrs->{order_by} ) eq 'ARRAY'
2428 ? [ @{ $attrs->{order_by} } ]
2429 : [ $attrs->{order_by} ]
2433 $attrs->{order_by} = [];
2436 my $collapse = $attrs->{collapse} || {};
2437 if ( my $prefetch = delete $attrs->{prefetch} ) {
2438 $prefetch = $self->_merge_attr( {}, $prefetch );
2440 my $seen = { %{ $attrs->{seen_join} || {} } };
2441 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2443 # bring joins back to level of current class
2445 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2446 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2447 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2449 push( @{ $attrs->{order_by} }, @pre_order );
2451 $attrs->{collapse} = $collapse;
2453 if ( $attrs->{page} ) {
2454 $attrs->{offset} ||= 0;
2455 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2458 return $self->{_attrs} = $attrs;
2462 my ($self, $attr) = @_;
2464 if (ref $attr eq 'HASH') {
2465 return $self->_rollout_hash($attr);
2466 } elsif (ref $attr eq 'ARRAY') {
2467 return $self->_rollout_array($attr);
2473 sub _rollout_array {
2474 my ($self, $attr) = @_;
2477 foreach my $element (@{$attr}) {
2478 if (ref $element eq 'HASH') {
2479 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2480 } elsif (ref $element eq 'ARRAY') {
2481 # XXX - should probably recurse here
2482 push( @rolled_array, @{$self->_rollout_array($element)} );
2484 push( @rolled_array, $element );
2487 return \@rolled_array;
2491 my ($self, $attr) = @_;
2494 foreach my $key (keys %{$attr}) {
2495 push( @rolled_array, { $key => $attr->{$key} } );
2497 return \@rolled_array;
2500 sub _calculate_score {
2501 my ($self, $a, $b) = @_;
2503 if (ref $b eq 'HASH') {
2504 my ($b_key) = keys %{$b};
2505 if (ref $a eq 'HASH') {
2506 my ($a_key) = keys %{$a};
2507 if ($a_key eq $b_key) {
2508 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2513 return ($a eq $b_key) ? 1 : 0;
2516 if (ref $a eq 'HASH') {
2517 my ($a_key) = keys %{$a};
2518 return ($b eq $a_key) ? 1 : 0;
2520 return ($b eq $a) ? 1 : 0;
2526 my ($self, $orig, $import) = @_;
2528 return $import unless defined($orig);
2529 return $orig unless defined($import);
2531 $orig = $self->_rollout_attr($orig);
2532 $import = $self->_rollout_attr($import);
2535 foreach my $import_element ( @{$import} ) {
2536 # find best candidate from $orig to merge $b_element into
2537 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2538 foreach my $orig_element ( @{$orig} ) {
2539 my $score = $self->_calculate_score( $orig_element, $import_element );
2540 if ($score > $best_candidate->{score}) {
2541 $best_candidate->{position} = $position;
2542 $best_candidate->{score} = $score;
2546 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2548 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2549 push( @{$orig}, $import_element );
2551 my $orig_best = $orig->[$best_candidate->{position}];
2552 # merge orig_best and b_element together and replace original with merged
2553 if (ref $orig_best ne 'HASH') {
2554 $orig->[$best_candidate->{position}] = $import_element;
2555 } elsif (ref $import_element eq 'HASH') {
2556 my ($key) = keys %{$orig_best};
2557 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2560 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2570 $self->_source_handle($_[0]->handle);
2572 $self->_source_handle->resolve;
2576 =head2 throw_exception
2578 See L<DBIx::Class::Schema/throw_exception> for details.
2582 sub throw_exception {
2584 if (ref $self && $self->_source_handle->schema) {
2585 $self->_source_handle->schema->throw_exception(@_)
2592 # XXX: FIXME: Attributes docs need clearing up
2596 Attributes are used to refine a ResultSet in various ways when
2597 searching for data. They can be passed to any method which takes an
2598 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2601 These are in no particular order:
2607 =item Value: ( $order_by | \@order_by | \%order_by )
2611 Which column(s) to order the results by. If a single column name, or
2612 an arrayref of names is supplied, the argument is passed through
2613 directly to SQL. The hashref syntax allows for connection-agnostic
2614 specification of ordering direction:
2616 For descending order:
2618 order_by => { -desc => [qw/col1 col2 col3/] }
2620 For explicit ascending order:
2622 order_by => { -asc => 'col' }
2624 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2625 supported, although you are strongly encouraged to use the hashref
2626 syntax as outlined above.
2632 =item Value: \@columns
2636 Shortcut to request a particular set of columns to be retrieved. Each
2637 column spec may be a string (a table column name), or a hash (in which
2638 case the key is the C<as> value, and the value is used as the C<select>
2639 expression). Adds C<me.> onto the start of any column without a C<.> in
2640 it and sets C<select> from that, then auto-populates C<as> from
2641 C<select> as normal. (You may also use the C<cols> attribute, as in
2642 earlier versions of DBIC.)
2648 =item Value: \@columns
2652 Indicates additional columns to be selected from storage. Works the same
2653 as L</columns> but adds columns to the selection. (You may also use the
2654 C<include_columns> attribute, as in earlier versions of DBIC). For
2657 $schema->resultset('CD')->search(undef, {
2658 '+columns' => ['artist.name'],
2662 would return all CDs and include a 'name' column to the information
2663 passed to object inflation. Note that the 'artist' is the name of the
2664 column (or relationship) accessor, and 'name' is the name of the column
2665 accessor in the related table.
2667 =head2 include_columns
2671 =item Value: \@columns
2675 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2681 =item Value: \@select_columns
2685 Indicates which columns should be selected from the storage. You can use
2686 column names, or in the case of RDBMS back ends, function or stored procedure
2689 $rs = $schema->resultset('Employee')->search(undef, {
2692 { count => 'employeeid' },
2697 When you use function/stored procedure names and do not supply an C<as>
2698 attribute, the column names returned are storage-dependent. E.g. MySQL would
2699 return a column named C<count(employeeid)> in the above example.
2705 Indicates additional columns to be selected from storage. Works the same as
2706 L</select> but adds columns to the selection.
2714 Indicates additional column names for those added via L</+select>. See L</as>.
2722 =item Value: \@inflation_names
2726 Indicates column names for object inflation. That is, C<as>
2727 indicates the name that the column can be accessed as via the
2728 C<get_column> method (or via the object accessor, B<if one already
2729 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2731 The C<as> attribute is used in conjunction with C<select>,
2732 usually when C<select> contains one or more function or stored
2735 $rs = $schema->resultset('Employee')->search(undef, {
2738 { count => 'employeeid' }
2740 as => ['name', 'employee_count'],
2743 my $employee = $rs->first(); # get the first Employee
2745 If the object against which the search is performed already has an accessor
2746 matching a column name specified in C<as>, the value can be retrieved using
2747 the accessor as normal:
2749 my $name = $employee->name();
2751 If on the other hand an accessor does not exist in the object, you need to
2752 use C<get_column> instead:
2754 my $employee_count = $employee->get_column('employee_count');
2756 You can create your own accessors if required - see
2757 L<DBIx::Class::Manual::Cookbook> for details.
2759 Please note: This will NOT insert an C<AS employee_count> into the SQL
2760 statement produced, it is used for internal access only. Thus
2761 attempting to use the accessor in an C<order_by> clause or similar
2762 will fail miserably.
2764 To get around this limitation, you can supply literal SQL to your
2765 C<select> attibute that contains the C<AS alias> text, eg:
2767 select => [\'myfield AS alias']
2773 =item Value: ($rel_name | \@rel_names | \%rel_names)
2777 Contains a list of relationships that should be joined for this query. For
2780 # Get CDs by Nine Inch Nails
2781 my $rs = $schema->resultset('CD')->search(
2782 { 'artist.name' => 'Nine Inch Nails' },
2783 { join => 'artist' }
2786 Can also contain a hash reference to refer to the other relation's relations.
2789 package MyApp::Schema::Track;
2790 use base qw/DBIx::Class/;
2791 __PACKAGE__->table('track');
2792 __PACKAGE__->add_columns(qw/trackid cd position title/);
2793 __PACKAGE__->set_primary_key('trackid');
2794 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2797 # In your application
2798 my $rs = $schema->resultset('Artist')->search(
2799 { 'track.title' => 'Teardrop' },
2801 join => { cd => 'track' },
2802 order_by => 'artist.name',
2806 You need to use the relationship (not the table) name in conditions,
2807 because they are aliased as such. The current table is aliased as "me", so
2808 you need to use me.column_name in order to avoid ambiguity. For example:
2810 # Get CDs from 1984 with a 'Foo' track
2811 my $rs = $schema->resultset('CD')->search(
2814 'tracks.name' => 'Foo'
2816 { join => 'tracks' }
2819 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2820 similarly for a third time). For e.g.
2822 my $rs = $schema->resultset('Artist')->search({
2823 'cds.title' => 'Down to Earth',
2824 'cds_2.title' => 'Popular',
2826 join => [ qw/cds cds/ ],
2829 will return a set of all artists that have both a cd with title 'Down
2830 to Earth' and a cd with title 'Popular'.
2832 If you want to fetch related objects from other tables as well, see C<prefetch>
2835 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2841 =item Value: ($rel_name | \@rel_names | \%rel_names)
2845 Contains one or more relationships that should be fetched along with
2846 the main query (when they are accessed afterwards the data will
2847 already be available, without extra queries to the database). This is
2848 useful for when you know you will need the related objects, because it
2849 saves at least one query:
2851 my $rs = $schema->resultset('Tag')->search(
2860 The initial search results in SQL like the following:
2862 SELECT tag.*, cd.*, artist.* FROM tag
2863 JOIN cd ON tag.cd = cd.cdid
2864 JOIN artist ON cd.artist = artist.artistid
2866 L<DBIx::Class> has no need to go back to the database when we access the
2867 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2870 Simple prefetches will be joined automatically, so there is no need
2871 for a C<join> attribute in the above search.
2873 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2874 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2875 with an accessor type of 'single' or 'filter'). A more complex example that
2876 prefetches an artists cds, the tracks on those cds, and the tags associted
2877 with that artist is given below (assuming many-to-many from artists to tags):
2879 my $rs = $schema->resultset('Artist')->search(
2883 { cds => 'tracks' },
2884 { artist_tags => 'tags' }
2890 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2891 attributes will be ignored.
2901 Makes the resultset paged and specifies the page to retrieve. Effectively
2902 identical to creating a non-pages resultset and then calling ->page($page)
2905 If L<rows> attribute is not specified it defualts to 10 rows per page.
2907 When you have a paged resultset, L</count> will only return the number
2908 of rows in the page. To get the total, use the L</pager> and call
2909 C<total_entries> on it.
2919 Specifes the maximum number of rows for direct retrieval or the number of
2920 rows per page if the page attribute or method is used.
2926 =item Value: $offset
2930 Specifies the (zero-based) row number for the first row to be returned, or the
2931 of the first row of the first page if paging is used.
2937 =item Value: \@columns
2941 A arrayref of columns to group by. Can include columns of joined tables.
2943 group_by => [qw/ column1 column2 ... /]
2949 =item Value: $condition
2953 HAVING is a select statement attribute that is applied between GROUP BY and
2954 ORDER BY. It is applied to the after the grouping calculations have been
2957 having => { 'count(employee)' => { '>=', 100 } }
2963 =item Value: (0 | 1)
2967 Set to 1 to group by all columns.
2973 Adds to the WHERE clause.
2975 # only return rows WHERE deleted IS NULL for all searches
2976 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2978 Can be overridden by passing C<{ where => undef }> as an attribute
2985 Set to 1 to cache search results. This prevents extra SQL queries if you
2986 revisit rows in your ResultSet:
2988 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2990 while( my $artist = $resultset->next ) {
2994 $rs->first; # without cache, this would issue a query
2996 By default, searches are not cached.
2998 For more examples of using these attributes, see
2999 L<DBIx::Class::Manual::Cookbook>.
3005 =item Value: \@from_clause
3009 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3010 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3013 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3015 C<join> will usually do what you need and it is strongly recommended that you
3016 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3017 And we really do mean "cannot", not just tried and failed. Attempting to use
3018 this because you're having problems with C<join> is like trying to use x86
3019 ASM because you've got a syntax error in your C. Trust us on this.
3021 Now, if you're still really, really sure you need to use this (and if you're
3022 not 100% sure, ask the mailing list first), here's an explanation of how this
3025 The syntax is as follows -
3028 { <alias1> => <table1> },
3030 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3031 [], # nested JOIN (optional)
3032 { <table1.column1> => <table2.column2>, ... (more conditions) },
3034 # More of the above [ ] may follow for additional joins
3041 ON <table1.column1> = <table2.column2>
3042 <more joins may follow>
3044 An easy way to follow the examples below is to remember the following:
3046 Anything inside "[]" is a JOIN
3047 Anything inside "{}" is a condition for the enclosing JOIN
3049 The following examples utilize a "person" table in a family tree application.
3050 In order to express parent->child relationships, this table is self-joined:
3052 # Person->belongs_to('father' => 'Person');
3053 # Person->belongs_to('mother' => 'Person');
3055 C<from> can be used to nest joins. Here we return all children with a father,
3056 then search against all mothers of those children:
3058 $rs = $schema->resultset('Person')->search(
3061 alias => 'mother', # alias columns in accordance with "from"
3063 { mother => 'person' },
3066 { child => 'person' },
3068 { father => 'person' },
3069 { 'father.person_id' => 'child.father_id' }
3072 { 'mother.person_id' => 'child.mother_id' }
3079 # SELECT mother.* FROM person mother
3082 # JOIN person father
3083 # ON ( father.person_id = child.father_id )
3085 # ON ( mother.person_id = child.mother_id )
3087 The type of any join can be controlled manually. To search against only people
3088 with a father in the person table, we could explicitly use C<INNER JOIN>:
3090 $rs = $schema->resultset('Person')->search(
3093 alias => 'child', # alias columns in accordance with "from"
3095 { child => 'person' },
3097 { father => 'person', -join_type => 'inner' },
3098 { 'father.id' => 'child.father_id' }
3105 # SELECT child.* FROM person child
3106 # INNER JOIN person father ON child.father_id = father.id
3108 If you need to express really complex joins or you need a subselect, you
3109 can supply literal SQL to C<from> via a scalar reference. In this case
3110 the contents of the scalar will replace the table name asscoiated with the
3113 WARNING: This technique might very well not work as expected on chained
3114 searches - you have been warned.
3116 # Assuming the Event resultsource is defined as:
3118 MySchema::Event->add_columns (
3121 is_auto_increment => 1,
3130 MySchema::Event->set_primary_key ('sequence');
3132 # This will get back the latest event for every location. The column
3133 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3134 # combo to limit the resultset
3136 $rs = $schema->resultset('Event');
3137 $table = $rs->result_source->name;
3138 $latest = $rs->search (
3141 (SELECT e1.* FROM $table e1
3143 ON e1.location = e2.location
3144 AND e1.sequence < e2.sequence
3145 WHERE e2.sequence is NULL
3150 # Equivalent SQL (with the DBIC chunks added):
3152 SELECT me.sequence, me.location, me.type FROM
3153 (SELECT e1.* FROM events e1
3155 ON e1.location = e2.location
3156 AND e1.sequence < e2.sequence
3157 WHERE e2.sequence is NULL
3164 =item Value: ( 'update' | 'shared' )
3168 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT