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/) {
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.
1154 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1155 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1156 not support C<DISTINCT> with multiple columns. If you are using such a
1157 database, you should only use columns from the main table in your C<group_by>
1164 return $self->search(@_)->count if @_ and defined $_[0];
1165 return scalar @{ $self->get_cache } if $self->get_cache;
1166 my $count = $self->_count;
1167 return 0 unless $count;
1169 # need to take offset from resolved attrs
1171 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1172 $count = $self->{attrs}{rows} if
1173 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1174 $count = 0 if ($count < 0);
1178 sub _count { # Separated out so pager can get the full count
1180 my $select = { count => '*' };
1182 my $attrs = { %{$self->_resolved_attrs} };
1183 if (my $group_by = delete $attrs->{group_by}) {
1184 delete $attrs->{having};
1185 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1186 # todo: try CONCAT for multi-column pk
1187 my @pk = $self->result_source->primary_columns;
1189 my $alias = $attrs->{alias};
1190 foreach my $column (@distinct) {
1191 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1192 @distinct = ($column);
1198 $select = { count => { distinct => \@distinct } };
1201 $attrs->{select} = $select;
1202 $attrs->{as} = [qw/count/];
1204 # offset, order by and page are not needed to count. record_filter is cdbi
1205 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1207 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1208 my ($count) = $tmp_rs->cursor->next;
1216 =head2 count_literal
1220 =item Arguments: $sql_fragment, @bind_values
1222 =item Return Value: $count
1226 Counts the results in a literal query. Equivalent to calling L</search_literal>
1227 with the passed arguments, then L</count>.
1231 sub count_literal { shift->search_literal(@_)->count; }
1237 =item Arguments: none
1239 =item Return Value: @objects
1243 Returns all elements in the resultset. Called implicitly if the resultset
1244 is returned in list context.
1251 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1254 return @{ $self->get_cache } if $self->get_cache;
1258 # TODO: don't call resolve here
1259 if (keys %{$self->_resolved_attrs->{collapse}}) {
1260 # if ($self->{attrs}{prefetch}) {
1261 # Using $self->cursor->all is really just an optimisation.
1262 # If we're collapsing has_many prefetches it probably makes
1263 # very little difference, and this is cleaner than hacking
1264 # _construct_object to survive the approach
1265 my @row = $self->cursor->next;
1267 push(@obj, $self->_construct_object(@row));
1268 @row = (exists $self->{stashed_row}
1269 ? @{delete $self->{stashed_row}}
1270 : $self->cursor->next);
1273 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1276 $self->set_cache(\@obj) if $self->{attrs}{cache};
1284 =item Arguments: none
1286 =item Return Value: $self
1290 Resets the resultset's cursor, so you can iterate through the elements again.
1296 delete $self->{_attrs} if exists $self->{_attrs};
1297 $self->{all_cache_position} = 0;
1298 $self->cursor->reset;
1306 =item Arguments: none
1308 =item Return Value: $object?
1312 Resets the resultset and returns an object for the first result (if the
1313 resultset returns anything).
1318 return $_[0]->reset->next;
1321 # _cond_for_update_delete
1323 # update/delete require the condition to be modified to handle
1324 # the differing SQL syntax available. This transforms the $self->{cond}
1325 # appropriately, returning the new condition.
1327 sub _cond_for_update_delete {
1328 my ($self, $full_cond) = @_;
1331 $full_cond ||= $self->{cond};
1332 # No-op. No condition, we're updating/deleting everything
1333 return $cond unless ref $full_cond;
1335 foreach my $pk ($self->result_source->primary_columns) {
1336 $cond->{$pk} = { -in => $self->get_column($pk)->as_query };
1347 =item Arguments: \%values
1349 =item Return Value: $storage_rv
1353 Sets the specified columns in the resultset to the supplied values in a
1354 single query. Return value will be true if the update succeeded or false
1355 if no records were updated; exact type of success value is storage-dependent.
1360 my ($self, $values) = @_;
1361 $self->throw_exception("Values for update must be a hash")
1362 unless ref $values eq 'HASH';
1364 my $cond = $self->_cond_for_update_delete;
1366 return $self->result_source->storage->update(
1367 $self->result_source, $values, $cond
1375 =item Arguments: \%values
1377 =item Return Value: 1
1381 Fetches all objects and updates them one at a time. Note that C<update_all>
1382 will run DBIC cascade triggers, while L</update> will not.
1387 my ($self, $values) = @_;
1388 $self->throw_exception("Values for update must be a hash")
1389 unless ref $values eq 'HASH';
1390 foreach my $obj ($self->all) {
1391 $obj->set_columns($values)->update;
1400 =item Arguments: none
1402 =item Return Value: 1
1406 Deletes the contents of the resultset from its result source. Note that this
1407 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1408 to run. See also L<DBIx::Class::Row/delete>.
1410 delete may not generate correct SQL for a query with joins or a resultset
1411 chained from a related resultset. In this case it will generate a warning:-
1413 In these cases you may find that delete_all is more appropriate, or you
1414 need to respecify your query in a way that can be expressed without a join.
1420 $self->throw_exception("Delete should not be passed any arguments")
1423 my $cond = $self->_cond_for_update_delete;
1425 $self->result_source->storage->delete($self->result_source, $cond);
1433 =item Arguments: none
1435 =item Return Value: 1
1439 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1440 will run DBIC cascade triggers, while L</delete> will not.
1446 $_->delete for $self->all;
1454 =item Arguments: \@data;
1458 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1459 For the arrayref of hashrefs style each hashref should be a structure suitable
1460 forsubmitting to a $resultset->create(...) method.
1462 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1463 to insert the data, as this is a faster method.
1465 Otherwise, each set of data is inserted into the database using
1466 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1467 objects is returned.
1469 Example: Assuming an Artist Class that has many CDs Classes relating:
1471 my $Artist_rs = $schema->resultset("Artist");
1473 ## Void Context Example
1474 $Artist_rs->populate([
1475 { artistid => 4, name => 'Manufactured Crap', cds => [
1476 { title => 'My First CD', year => 2006 },
1477 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1480 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1481 { title => 'My parents sold me to a record company' ,year => 2005 },
1482 { title => 'Why Am I So Ugly?', year => 2006 },
1483 { title => 'I Got Surgery and am now Popular', year => 2007 }
1488 ## Array Context Example
1489 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1490 { name => "Artist One"},
1491 { name => "Artist Two"},
1492 { name => "Artist Three", cds=> [
1493 { title => "First CD", year => 2007},
1494 { title => "Second CD", year => 2008},
1498 print $ArtistOne->name; ## response is 'Artist One'
1499 print $ArtistThree->cds->count ## reponse is '2'
1501 For the arrayref of arrayrefs style, the first element should be a list of the
1502 fieldsnames to which the remaining elements are rows being inserted. For
1505 $Arstist_rs->populate([
1506 [qw/artistid name/],
1507 [100, 'A Formally Unknown Singer'],
1508 [101, 'A singer that jumped the shark two albums ago'],
1509 [102, 'An actually cool singer.'],
1512 Please note an important effect on your data when choosing between void and
1513 wantarray context. Since void context goes straight to C<insert_bulk> in
1514 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1515 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1516 create primary keys for you, you will find that your PKs are empty. In this
1517 case you will have to use the wantarray context in order to create those
1523 my $self = shift @_;
1524 my $data = ref $_[0][0] eq 'HASH'
1525 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1526 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1528 if(defined wantarray) {
1530 foreach my $item (@$data) {
1531 push(@created, $self->create($item));
1535 my ($first, @rest) = @$data;
1537 my @names = grep {!ref $first->{$_}} keys %$first;
1538 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1539 my @pks = $self->result_source->primary_columns;
1541 ## do the belongs_to relationships
1542 foreach my $index (0..$#$data) {
1543 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1544 my @ret = $self->populate($data);
1548 foreach my $rel (@rels) {
1549 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1550 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1551 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1552 my $related = $result->result_source->resolve_condition(
1553 $result->result_source->relationship_info($reverse)->{cond},
1558 delete $data->[$index]->{$rel};
1559 $data->[$index] = {%{$data->[$index]}, %$related};
1561 push @names, keys %$related if $index == 0;
1565 ## do bulk insert on current row
1566 my @values = map { [ @$_{@names} ] } @$data;
1568 $self->result_source->storage->insert_bulk(
1569 $self->result_source,
1574 ## do the has_many relationships
1575 foreach my $item (@$data) {
1577 foreach my $rel (@rels) {
1578 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1580 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1581 || $self->throw_exception('Cannot find the relating object.');
1583 my $child = $parent->$rel;
1585 my $related = $child->result_source->resolve_condition(
1586 $parent->result_source->relationship_info($rel)->{cond},
1591 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1592 my @populate = map { {%$_, %$related} } @rows_to_add;
1594 $child->populate( \@populate );
1600 =head2 _normalize_populate_args ($args)
1602 Private method used by L</populate> to normalize its incoming arguments. Factored
1603 out in case you want to subclass and accept new argument structures to the
1604 L</populate> method.
1608 sub _normalize_populate_args {
1609 my ($self, $data) = @_;
1610 my @names = @{shift(@$data)};
1611 my @results_to_create;
1612 foreach my $datum (@$data) {
1613 my %result_to_create;
1614 foreach my $index (0..$#names) {
1615 $result_to_create{$names[$index]} = $$datum[$index];
1617 push @results_to_create, \%result_to_create;
1619 return \@results_to_create;
1626 =item Arguments: none
1628 =item Return Value: $pager
1632 Return Value a L<Data::Page> object for the current resultset. Only makes
1633 sense for queries with a C<page> attribute.
1635 To get the full count of entries for a paged resultset, call
1636 C<total_entries> on the L<Data::Page> object.
1642 my $attrs = $self->{attrs};
1643 $self->throw_exception("Can't create pager for non-paged rs")
1644 unless $self->{attrs}{page};
1645 $attrs->{rows} ||= 10;
1646 return $self->{pager} ||= Data::Page->new(
1647 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1654 =item Arguments: $page_number
1656 =item Return Value: $rs
1660 Returns a resultset for the $page_number page of the resultset on which page
1661 is called, where each page contains a number of rows equal to the 'rows'
1662 attribute set on the resultset (10 by default).
1667 my ($self, $page) = @_;
1668 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1675 =item Arguments: \%vals
1677 =item Return Value: $rowobject
1681 Creates a new row object in the resultset's result class and returns
1682 it. The row is not inserted into the database at this point, call
1683 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1684 will tell you whether the row object has been inserted or not.
1686 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1691 my ($self, $values) = @_;
1692 $self->throw_exception( "new_result needs a hash" )
1693 unless (ref $values eq 'HASH');
1696 my $alias = $self->{attrs}{alias};
1699 defined $self->{cond}
1700 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1702 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1703 $new{-from_resultset} = [ keys %new ] if keys %new;
1705 $self->throw_exception(
1706 "Can't abstract implicit construct, condition not a hash"
1707 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1709 my $collapsed_cond = (
1711 ? $self->_collapse_cond($self->{cond})
1715 # precendence must be given to passed values over values inherited from
1716 # the cond, so the order here is important.
1717 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1718 while( my($col,$value) = each %implied ){
1719 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1720 $new{$col} = $value->{'='};
1723 $new{$col} = $value if $self->_is_deterministic_value($value);
1729 %{ $self->_remove_alias($values, $alias) },
1730 -source_handle => $self->_source_handle,
1731 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1734 return $self->result_class->new(\%new);
1737 # _is_deterministic_value
1739 # Make an effor to strip non-deterministic values from the condition,
1740 # to make sure new_result chokes less
1742 sub _is_deterministic_value {
1745 my $ref_type = ref $value;
1746 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1747 return 1 if Scalar::Util::blessed($value);
1753 # Recursively collapse the condition.
1755 sub _collapse_cond {
1756 my ($self, $cond, $collapsed) = @_;
1760 if (ref $cond eq 'ARRAY') {
1761 foreach my $subcond (@$cond) {
1762 next unless ref $subcond; # -or
1763 # warn "ARRAY: " . Dumper $subcond;
1764 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1767 elsif (ref $cond eq 'HASH') {
1768 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1769 foreach my $subcond (@{$cond->{-and}}) {
1770 # warn "HASH: " . Dumper $subcond;
1771 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1775 # warn "LEAF: " . Dumper $cond;
1776 foreach my $col (keys %$cond) {
1777 my $value = $cond->{$col};
1778 $collapsed->{$col} = $value;
1788 # Remove the specified alias from the specified query hash. A copy is made so
1789 # the original query is not modified.
1792 my ($self, $query, $alias) = @_;
1794 my %orig = %{ $query || {} };
1797 foreach my $key (keys %orig) {
1799 $unaliased{$key} = $orig{$key};
1802 $unaliased{$1} = $orig{$key}
1803 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1809 =head2 as_query (EXPERIMENTAL)
1813 =item Arguments: none
1815 =item Return Value: \[ $sql, @bind ]
1819 Returns the SQL query and bind vars associated with the invocant.
1821 This is generally used as the RHS for a subquery.
1823 B<NOTE>: This feature is still experimental.
1827 sub as_query { return shift->cursor->as_query(@_) }
1833 =item Arguments: \%vals, \%attrs?
1835 =item Return Value: $rowobject
1839 my $artist = $schema->resultset('Artist')->find_or_new(
1840 { artist => 'fred' }, { key => 'artists' });
1842 $cd->cd_to_producer->find_or_new({ producer => $producer },
1843 { key => 'primary });
1845 Find an existing record from this resultset, based on its primary
1846 key, or a unique constraint. If none exists, instantiate a new result
1847 object and return it. The object will not be saved into your storage
1848 until you call L<DBIx::Class::Row/insert> on it.
1850 You most likely want this method when looking for existing rows using
1851 a unique constraint that is not the primary key, or looking for
1854 If you want objects to be saved immediately, use L</find_or_create> instead.
1856 B<Note>: C<find_or_new> is probably not what you want when creating a
1857 new row in a table that uses primary keys supplied by the
1858 database. Passing in a primary key column with a value of I<undef>
1859 will cause L</find> to attempt to search for a row with a value of
1866 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1867 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1868 my $exists = $self->find($hash, $attrs);
1869 return defined $exists ? $exists : $self->new_result($hash);
1876 =item Arguments: \%vals
1878 =item Return Value: a L<DBIx::Class::Row> $object
1882 Attempt to create a single new row or a row with multiple related rows
1883 in the table represented by the resultset (and related tables). This
1884 will not check for duplicate rows before inserting, use
1885 L</find_or_create> to do that.
1887 To create one row for this resultset, pass a hashref of key/value
1888 pairs representing the columns of the table and the values you wish to
1889 store. If the appropriate relationships are set up, foreign key fields
1890 can also be passed an object representing the foreign row, and the
1891 value will be set to its primary key.
1893 To create related objects, pass a hashref for the value if the related
1894 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1895 and use the name of the relationship as the key. (NOT the name of the field,
1896 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1897 of hashrefs containing the data for each of the rows to create in the foreign
1898 tables, again using the relationship name as the key.
1900 Instead of hashrefs of plain related data (key/value pairs), you may
1901 also pass new or inserted objects. New objects (not inserted yet, see
1902 L</new>), will be inserted into their appropriate tables.
1904 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1906 Example of creating a new row.
1908 $person_rs->create({
1909 name=>"Some Person",
1910 email=>"somebody@someplace.com"
1913 Example of creating a new row and also creating rows in a related C<has_many>
1914 or C<has_one> resultset. Note Arrayref.
1917 { artistid => 4, name => 'Manufactured Crap', cds => [
1918 { title => 'My First CD', year => 2006 },
1919 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1924 Example of creating a new row and also creating a row in a related
1925 C<belongs_to>resultset. Note Hashref.
1928 title=>"Music for Silly Walks",
1931 name=>"Silly Musician",
1938 my ($self, $attrs) = @_;
1939 $self->throw_exception( "create needs a hashref" )
1940 unless ref $attrs eq 'HASH';
1941 return $self->new_result($attrs)->insert;
1944 =head2 find_or_create
1948 =item Arguments: \%vals, \%attrs?
1950 =item Return Value: $rowobject
1954 $cd->cd_to_producer->find_or_create({ producer => $producer },
1955 { key => 'primary });
1957 Tries to find a record based on its primary key or unique constraints; if none
1958 is found, creates one and returns that instead.
1960 my $cd = $schema->resultset('CD')->find_or_create({
1962 artist => 'Massive Attack',
1963 title => 'Mezzanine',
1967 Also takes an optional C<key> attribute, to search by a specific key or unique
1968 constraint. For example:
1970 my $cd = $schema->resultset('CD')->find_or_create(
1972 artist => 'Massive Attack',
1973 title => 'Mezzanine',
1975 { key => 'cd_artist_title' }
1978 B<Note>: Because find_or_create() reads from the database and then
1979 possibly inserts based on the result, this method is subject to a race
1980 condition. Another process could create a record in the table after
1981 the find has completed and before the create has started. To avoid
1982 this problem, use find_or_create() inside a transaction.
1984 B<Note>: C<find_or_create> is probably not what you want when creating
1985 a new row in a table that uses primary keys supplied by the
1986 database. Passing in a primary key column with a value of I<undef>
1987 will cause L</find> to attempt to search for a row with a value of
1990 See also L</find> and L</update_or_create>. For information on how to declare
1991 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1995 sub find_or_create {
1997 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1998 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1999 my $exists = $self->find($hash, $attrs);
2000 return defined $exists ? $exists : $self->create($hash);
2003 =head2 update_or_create
2007 =item Arguments: \%col_values, { key => $unique_constraint }?
2009 =item Return Value: $rowobject
2013 $resultset->update_or_create({ col => $val, ... });
2015 First, searches for an existing row matching one of the unique constraints
2016 (including the primary key) on the source of this resultset. If a row is
2017 found, updates it with the other given column values. Otherwise, creates a new
2020 Takes an optional C<key> attribute to search on a specific unique constraint.
2023 # In your application
2024 my $cd = $schema->resultset('CD')->update_or_create(
2026 artist => 'Massive Attack',
2027 title => 'Mezzanine',
2030 { key => 'cd_artist_title' }
2033 $cd->cd_to_producer->update_or_create({
2034 producer => $producer,
2041 If no C<key> is specified, it searches on all unique constraints defined on the
2042 source, including the primary key.
2044 If the C<key> is specified as C<primary>, it searches only on the primary key.
2046 See also L</find> and L</find_or_create>. For information on how to declare
2047 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2049 B<Note>: C<update_or_create> is probably not what you want when
2050 looking for a row in a table that uses primary keys supplied by the
2051 database, unless you actually have a key value. Passing in a primary
2052 key column with a value of I<undef> will cause L</find> to attempt to
2053 search for a row with a value of I<NULL>.
2057 sub update_or_create {
2059 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2060 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2062 my $row = $self->find($cond, $attrs);
2064 $row->update($cond);
2068 return $self->create($cond);
2071 =head2 update_or_new
2075 =item Arguments: \%col_values, { key => $unique_constraint }?
2077 =item Return Value: $rowobject
2081 $resultset->update_or_new({ col => $val, ... });
2083 First, searches for an existing row matching one of the unique constraints
2084 (including the primary key) on the source of this resultset. If a row is
2085 found, updates it with the other given column values. Otherwise, instantiate
2086 a new result object and return it. The object will not be saved into your storage
2087 until you call L<DBIx::Class::Row/insert> on it.
2089 Takes an optional C<key> attribute to search on a specific unique constraint.
2092 # In your application
2093 my $cd = $schema->resultset('CD')->update_or_new(
2095 artist => 'Massive Attack',
2096 title => 'Mezzanine',
2099 { key => 'cd_artist_title' }
2102 if ($cd->in_storage) {
2103 # the cd was updated
2106 # the cd is not yet in the database, let's insert it
2110 See also L</find>, L</find_or_create> and L<find_or_new>.
2116 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2117 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2119 my $row = $self->find( $cond, $attrs );
2120 if ( defined $row ) {
2121 $row->update($cond);
2125 return $self->new_result($cond);
2132 =item Arguments: none
2134 =item Return Value: \@cache_objects?
2138 Gets the contents of the cache for the resultset, if the cache is set.
2140 The cache is populated either by using the L</prefetch> attribute to
2141 L</search> or by calling L</set_cache>.
2153 =item Arguments: \@cache_objects
2155 =item Return Value: \@cache_objects
2159 Sets the contents of the cache for the resultset. Expects an arrayref
2160 of objects of the same class as those produced by the resultset. Note that
2161 if the cache is set the resultset will return the cached objects rather
2162 than re-querying the database even if the cache attr is not set.
2164 The contents of the cache can also be populated by using the
2165 L</prefetch> attribute to L</search>.
2170 my ( $self, $data ) = @_;
2171 $self->throw_exception("set_cache requires an arrayref")
2172 if defined($data) && (ref $data ne 'ARRAY');
2173 $self->{all_cache} = $data;
2180 =item Arguments: none
2182 =item Return Value: []
2186 Clears the cache for the resultset.
2191 shift->set_cache(undef);
2194 =head2 related_resultset
2198 =item Arguments: $relationship_name
2200 =item Return Value: $resultset
2204 Returns a related resultset for the supplied relationship name.
2206 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2210 sub related_resultset {
2211 my ($self, $rel) = @_;
2213 $self->{related_resultsets} ||= {};
2214 return $self->{related_resultsets}{$rel} ||= do {
2215 my $rel_obj = $self->result_source->relationship_info($rel);
2217 $self->throw_exception(
2218 "search_related: result source '" . $self->result_source->source_name .
2219 "' has no such relationship $rel")
2222 my ($from,$seen) = $self->_resolve_from($rel);
2224 my $join_count = $seen->{$rel};
2225 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2227 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2228 my %attrs = %{$self->{attrs}||{}};
2229 delete @attrs{qw(result_class alias)};
2233 if (my $cache = $self->get_cache) {
2234 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2235 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2240 my $rel_source = $self->result_source->related_source($rel);
2244 # The reason we do this now instead of passing the alias to the
2245 # search_rs below is that if you wrap/overload resultset on the
2246 # source you need to know what alias it's -going- to have for things
2247 # to work sanely (e.g. RestrictWithObject wants to be able to add
2248 # extra query restrictions, and these may need to be $alias.)
2250 my $attrs = $rel_source->resultset_attributes;
2251 local $attrs->{alias} = $alias;
2253 $rel_source->resultset
2261 where => $self->{cond},
2266 $new->set_cache($new_cache) if $new_cache;
2271 =head2 current_source_alias
2275 =item Arguments: none
2277 =item Return Value: $source_alias
2281 Returns the current table alias for the result source this resultset is built
2282 on, that will be used in the SQL query. Usually it is C<me>.
2284 Currently the source alias that refers to the result set returned by a
2285 L</search>/L</find> family method depends on how you got to the resultset: it's
2286 C<me> by default, but eg. L</search_related> aliases it to the related result
2287 source name (and keeps C<me> referring to the original result set). The long
2288 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2289 (and make this method unnecessary).
2291 Thus it's currently necessary to use this method in predefined queries (see
2292 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2293 source alias of the current result set:
2295 # in a result set class
2297 my ($self, $user) = @_;
2299 my $me = $self->current_source_alias;
2301 return $self->search(
2302 "$me.modified" => $user->id,
2308 sub current_source_alias {
2311 return ($self->{attrs} || {})->{alias} || 'me';
2315 my ($self, $extra_join) = @_;
2316 my $source = $self->result_source;
2317 my $attrs = $self->{attrs};
2319 my $from = $attrs->{from}
2320 || [ { $attrs->{alias} => $source->from } ];
2322 my $seen = { %{$attrs->{seen_join}||{}} };
2324 my $join = ($attrs->{join}
2325 ? [ $attrs->{join}, $extra_join ]
2328 # we need to take the prefetch the attrs into account before we
2329 # ->resolve_join as otherwise they get lost - captainL
2330 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2334 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2337 return ($from,$seen);
2340 sub _resolved_attrs {
2342 return $self->{_attrs} if $self->{_attrs};
2344 my $attrs = { %{ $self->{attrs} || {} } };
2345 my $source = $self->result_source;
2346 my $alias = $attrs->{alias};
2348 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2351 # build columns (as long as select isn't set) into a set of as/select hashes
2352 unless ( $attrs->{select} ) {
2354 ( ref($_) eq 'HASH' )
2358 /^\Q${alias}.\E(.+)$/
2369 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2371 # add the additional columns on
2372 foreach ( 'include_columns', '+columns' ) {
2373 push @colbits, map {
2374 ( ref($_) eq 'HASH' )
2376 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2377 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2380 # start with initial select items
2381 if ( $attrs->{select} ) {
2383 ( ref $attrs->{select} eq 'ARRAY' )
2384 ? [ @{ $attrs->{select} } ]
2385 : [ $attrs->{select} ];
2389 ref $attrs->{as} eq 'ARRAY'
2390 ? [ @{ $attrs->{as} } ]
2393 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2398 # otherwise we intialise select & as to empty
2399 $attrs->{select} = [];
2403 # now add colbits to select/as
2404 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2405 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2408 if ( $adds = delete $attrs->{'+select'} ) {
2409 $adds = [$adds] unless ref $adds eq 'ARRAY';
2411 @{ $attrs->{select} },
2412 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2415 if ( $adds = delete $attrs->{'+as'} ) {
2416 $adds = [$adds] unless ref $adds eq 'ARRAY';
2417 push( @{ $attrs->{as} }, @$adds );
2420 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2422 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2423 my $join = delete $attrs->{join} || {};
2425 if ( defined $attrs->{prefetch} ) {
2426 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2430 $attrs->{from} = # have to copy here to avoid corrupting the original
2432 @{ $attrs->{from} },
2433 $source->resolve_join(
2434 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2440 $attrs->{group_by} ||= $attrs->{select}
2441 if delete $attrs->{distinct};
2442 if ( $attrs->{order_by} ) {
2443 $attrs->{order_by} = (
2444 ref( $attrs->{order_by} ) eq 'ARRAY'
2445 ? [ @{ $attrs->{order_by} } ]
2446 : [ $attrs->{order_by} ]
2450 $attrs->{order_by} = [];
2453 my $collapse = $attrs->{collapse} || {};
2454 if ( my $prefetch = delete $attrs->{prefetch} ) {
2455 $prefetch = $self->_merge_attr( {}, $prefetch );
2457 my $seen = { %{ $attrs->{seen_join} || {} } };
2458 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2460 # bring joins back to level of current class
2462 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2463 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2464 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2466 push( @{ $attrs->{order_by} }, @pre_order );
2468 $attrs->{collapse} = $collapse;
2470 if ( $attrs->{page} ) {
2471 $attrs->{offset} ||= 0;
2472 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2475 return $self->{_attrs} = $attrs;
2479 my ($self, $attr) = @_;
2481 if (ref $attr eq 'HASH') {
2482 return $self->_rollout_hash($attr);
2483 } elsif (ref $attr eq 'ARRAY') {
2484 return $self->_rollout_array($attr);
2490 sub _rollout_array {
2491 my ($self, $attr) = @_;
2494 foreach my $element (@{$attr}) {
2495 if (ref $element eq 'HASH') {
2496 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2497 } elsif (ref $element eq 'ARRAY') {
2498 # XXX - should probably recurse here
2499 push( @rolled_array, @{$self->_rollout_array($element)} );
2501 push( @rolled_array, $element );
2504 return \@rolled_array;
2508 my ($self, $attr) = @_;
2511 foreach my $key (keys %{$attr}) {
2512 push( @rolled_array, { $key => $attr->{$key} } );
2514 return \@rolled_array;
2517 sub _calculate_score {
2518 my ($self, $a, $b) = @_;
2520 if (ref $b eq 'HASH') {
2521 my ($b_key) = keys %{$b};
2522 if (ref $a eq 'HASH') {
2523 my ($a_key) = keys %{$a};
2524 if ($a_key eq $b_key) {
2525 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2530 return ($a eq $b_key) ? 1 : 0;
2533 if (ref $a eq 'HASH') {
2534 my ($a_key) = keys %{$a};
2535 return ($b eq $a_key) ? 1 : 0;
2537 return ($b eq $a) ? 1 : 0;
2543 my ($self, $orig, $import) = @_;
2545 return $import unless defined($orig);
2546 return $orig unless defined($import);
2548 $orig = $self->_rollout_attr($orig);
2549 $import = $self->_rollout_attr($import);
2552 foreach my $import_element ( @{$import} ) {
2553 # find best candidate from $orig to merge $b_element into
2554 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2555 foreach my $orig_element ( @{$orig} ) {
2556 my $score = $self->_calculate_score( $orig_element, $import_element );
2557 if ($score > $best_candidate->{score}) {
2558 $best_candidate->{position} = $position;
2559 $best_candidate->{score} = $score;
2563 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2565 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2566 push( @{$orig}, $import_element );
2568 my $orig_best = $orig->[$best_candidate->{position}];
2569 # merge orig_best and b_element together and replace original with merged
2570 if (ref $orig_best ne 'HASH') {
2571 $orig->[$best_candidate->{position}] = $import_element;
2572 } elsif (ref $import_element eq 'HASH') {
2573 my ($key) = keys %{$orig_best};
2574 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2577 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2587 $self->_source_handle($_[0]->handle);
2589 $self->_source_handle->resolve;
2593 =head2 throw_exception
2595 See L<DBIx::Class::Schema/throw_exception> for details.
2599 sub throw_exception {
2601 if (ref $self && $self->_source_handle->schema) {
2602 $self->_source_handle->schema->throw_exception(@_)
2609 # XXX: FIXME: Attributes docs need clearing up
2613 Attributes are used to refine a ResultSet in various ways when
2614 searching for data. They can be passed to any method which takes an
2615 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2618 These are in no particular order:
2624 =item Value: ( $order_by | \@order_by | \%order_by )
2628 Which column(s) to order the results by. If a single column name, or
2629 an arrayref of names is supplied, the argument is passed through
2630 directly to SQL. The hashref syntax allows for connection-agnostic
2631 specification of ordering direction:
2633 For descending order:
2635 order_by => { -desc => [qw/col1 col2 col3/] }
2637 For explicit ascending order:
2639 order_by => { -asc => 'col' }
2641 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2642 supported, although you are strongly encouraged to use the hashref
2643 syntax as outlined above.
2649 =item Value: \@columns
2653 Shortcut to request a particular set of columns to be retrieved. Each
2654 column spec may be a string (a table column name), or a hash (in which
2655 case the key is the C<as> value, and the value is used as the C<select>
2656 expression). Adds C<me.> onto the start of any column without a C<.> in
2657 it and sets C<select> from that, then auto-populates C<as> from
2658 C<select> as normal. (You may also use the C<cols> attribute, as in
2659 earlier versions of DBIC.)
2665 =item Value: \@columns
2669 Indicates additional columns to be selected from storage. Works the same
2670 as L</columns> but adds columns to the selection. (You may also use the
2671 C<include_columns> attribute, as in earlier versions of DBIC). For
2674 $schema->resultset('CD')->search(undef, {
2675 '+columns' => ['artist.name'],
2679 would return all CDs and include a 'name' column to the information
2680 passed to object inflation. Note that the 'artist' is the name of the
2681 column (or relationship) accessor, and 'name' is the name of the column
2682 accessor in the related table.
2684 =head2 include_columns
2688 =item Value: \@columns
2692 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2698 =item Value: \@select_columns
2702 Indicates which columns should be selected from the storage. You can use
2703 column names, or in the case of RDBMS back ends, function or stored procedure
2706 $rs = $schema->resultset('Employee')->search(undef, {
2709 { count => 'employeeid' },
2714 When you use function/stored procedure names and do not supply an C<as>
2715 attribute, the column names returned are storage-dependent. E.g. MySQL would
2716 return a column named C<count(employeeid)> in the above example.
2722 Indicates additional columns to be selected from storage. Works the same as
2723 L</select> but adds columns to the selection.
2731 Indicates additional column names for those added via L</+select>. See L</as>.
2739 =item Value: \@inflation_names
2743 Indicates column names for object inflation. That is, C<as>
2744 indicates the name that the column can be accessed as via the
2745 C<get_column> method (or via the object accessor, B<if one already
2746 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2748 The C<as> attribute is used in conjunction with C<select>,
2749 usually when C<select> contains one or more function or stored
2752 $rs = $schema->resultset('Employee')->search(undef, {
2755 { count => 'employeeid' }
2757 as => ['name', 'employee_count'],
2760 my $employee = $rs->first(); # get the first Employee
2762 If the object against which the search is performed already has an accessor
2763 matching a column name specified in C<as>, the value can be retrieved using
2764 the accessor as normal:
2766 my $name = $employee->name();
2768 If on the other hand an accessor does not exist in the object, you need to
2769 use C<get_column> instead:
2771 my $employee_count = $employee->get_column('employee_count');
2773 You can create your own accessors if required - see
2774 L<DBIx::Class::Manual::Cookbook> for details.
2776 Please note: This will NOT insert an C<AS employee_count> into the SQL
2777 statement produced, it is used for internal access only. Thus
2778 attempting to use the accessor in an C<order_by> clause or similar
2779 will fail miserably.
2781 To get around this limitation, you can supply literal SQL to your
2782 C<select> attibute that contains the C<AS alias> text, eg:
2784 select => [\'myfield AS alias']
2790 =item Value: ($rel_name | \@rel_names | \%rel_names)
2794 Contains a list of relationships that should be joined for this query. For
2797 # Get CDs by Nine Inch Nails
2798 my $rs = $schema->resultset('CD')->search(
2799 { 'artist.name' => 'Nine Inch Nails' },
2800 { join => 'artist' }
2803 Can also contain a hash reference to refer to the other relation's relations.
2806 package MyApp::Schema::Track;
2807 use base qw/DBIx::Class/;
2808 __PACKAGE__->table('track');
2809 __PACKAGE__->add_columns(qw/trackid cd position title/);
2810 __PACKAGE__->set_primary_key('trackid');
2811 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2814 # In your application
2815 my $rs = $schema->resultset('Artist')->search(
2816 { 'track.title' => 'Teardrop' },
2818 join => { cd => 'track' },
2819 order_by => 'artist.name',
2823 You need to use the relationship (not the table) name in conditions,
2824 because they are aliased as such. The current table is aliased as "me", so
2825 you need to use me.column_name in order to avoid ambiguity. For example:
2827 # Get CDs from 1984 with a 'Foo' track
2828 my $rs = $schema->resultset('CD')->search(
2831 'tracks.name' => 'Foo'
2833 { join => 'tracks' }
2836 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2837 similarly for a third time). For e.g.
2839 my $rs = $schema->resultset('Artist')->search({
2840 'cds.title' => 'Down to Earth',
2841 'cds_2.title' => 'Popular',
2843 join => [ qw/cds cds/ ],
2846 will return a set of all artists that have both a cd with title 'Down
2847 to Earth' and a cd with title 'Popular'.
2849 If you want to fetch related objects from other tables as well, see C<prefetch>
2852 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2858 =item Value: ($rel_name | \@rel_names | \%rel_names)
2862 Contains one or more relationships that should be fetched along with
2863 the main query (when they are accessed afterwards the data will
2864 already be available, without extra queries to the database). This is
2865 useful for when you know you will need the related objects, because it
2866 saves at least one query:
2868 my $rs = $schema->resultset('Tag')->search(
2877 The initial search results in SQL like the following:
2879 SELECT tag.*, cd.*, artist.* FROM tag
2880 JOIN cd ON tag.cd = cd.cdid
2881 JOIN artist ON cd.artist = artist.artistid
2883 L<DBIx::Class> has no need to go back to the database when we access the
2884 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2887 Simple prefetches will be joined automatically, so there is no need
2888 for a C<join> attribute in the above search.
2890 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2891 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2892 with an accessor type of 'single' or 'filter'). A more complex example that
2893 prefetches an artists cds, the tracks on those cds, and the tags associted
2894 with that artist is given below (assuming many-to-many from artists to tags):
2896 my $rs = $schema->resultset('Artist')->search(
2900 { cds => 'tracks' },
2901 { artist_tags => 'tags' }
2907 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2908 attributes will be ignored.
2918 Makes the resultset paged and specifies the page to retrieve. Effectively
2919 identical to creating a non-pages resultset and then calling ->page($page)
2922 If L<rows> attribute is not specified it defualts to 10 rows per page.
2924 When you have a paged resultset, L</count> will only return the number
2925 of rows in the page. To get the total, use the L</pager> and call
2926 C<total_entries> on it.
2936 Specifes the maximum number of rows for direct retrieval or the number of
2937 rows per page if the page attribute or method is used.
2943 =item Value: $offset
2947 Specifies the (zero-based) row number for the first row to be returned, or the
2948 of the first row of the first page if paging is used.
2954 =item Value: \@columns
2958 A arrayref of columns to group by. Can include columns of joined tables.
2960 group_by => [qw/ column1 column2 ... /]
2966 =item Value: $condition
2970 HAVING is a select statement attribute that is applied between GROUP BY and
2971 ORDER BY. It is applied to the after the grouping calculations have been
2974 having => { 'count(employee)' => { '>=', 100 } }
2980 =item Value: (0 | 1)
2984 Set to 1 to group by all columns.
2990 Adds to the WHERE clause.
2992 # only return rows WHERE deleted IS NULL for all searches
2993 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2995 Can be overridden by passing C<{ where => undef }> as an attribute
3002 Set to 1 to cache search results. This prevents extra SQL queries if you
3003 revisit rows in your ResultSet:
3005 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3007 while( my $artist = $resultset->next ) {
3011 $rs->first; # without cache, this would issue a query
3013 By default, searches are not cached.
3015 For more examples of using these attributes, see
3016 L<DBIx::Class::Manual::Cookbook>.
3022 =item Value: \@from_clause
3026 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3027 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3030 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3032 C<join> will usually do what you need and it is strongly recommended that you
3033 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3034 And we really do mean "cannot", not just tried and failed. Attempting to use
3035 this because you're having problems with C<join> is like trying to use x86
3036 ASM because you've got a syntax error in your C. Trust us on this.
3038 Now, if you're still really, really sure you need to use this (and if you're
3039 not 100% sure, ask the mailing list first), here's an explanation of how this
3042 The syntax is as follows -
3045 { <alias1> => <table1> },
3047 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3048 [], # nested JOIN (optional)
3049 { <table1.column1> => <table2.column2>, ... (more conditions) },
3051 # More of the above [ ] may follow for additional joins
3058 ON <table1.column1> = <table2.column2>
3059 <more joins may follow>
3061 An easy way to follow the examples below is to remember the following:
3063 Anything inside "[]" is a JOIN
3064 Anything inside "{}" is a condition for the enclosing JOIN
3066 The following examples utilize a "person" table in a family tree application.
3067 In order to express parent->child relationships, this table is self-joined:
3069 # Person->belongs_to('father' => 'Person');
3070 # Person->belongs_to('mother' => 'Person');
3072 C<from> can be used to nest joins. Here we return all children with a father,
3073 then search against all mothers of those children:
3075 $rs = $schema->resultset('Person')->search(
3078 alias => 'mother', # alias columns in accordance with "from"
3080 { mother => 'person' },
3083 { child => 'person' },
3085 { father => 'person' },
3086 { 'father.person_id' => 'child.father_id' }
3089 { 'mother.person_id' => 'child.mother_id' }
3096 # SELECT mother.* FROM person mother
3099 # JOIN person father
3100 # ON ( father.person_id = child.father_id )
3102 # ON ( mother.person_id = child.mother_id )
3104 The type of any join can be controlled manually. To search against only people
3105 with a father in the person table, we could explicitly use C<INNER JOIN>:
3107 $rs = $schema->resultset('Person')->search(
3110 alias => 'child', # alias columns in accordance with "from"
3112 { child => 'person' },
3114 { father => 'person', -join_type => 'inner' },
3115 { 'father.id' => 'child.father_id' }
3122 # SELECT child.* FROM person child
3123 # INNER JOIN person father ON child.father_id = father.id
3125 If you need to express really complex joins or you need a subselect, you
3126 can supply literal SQL to C<from> via a scalar reference. In this case
3127 the contents of the scalar will replace the table name asscoiated with the
3130 WARNING: This technique might very well not work as expected on chained
3131 searches - you have been warned.
3133 # Assuming the Event resultsource is defined as:
3135 MySchema::Event->add_columns (
3138 is_auto_increment => 1,
3147 MySchema::Event->set_primary_key ('sequence');
3149 # This will get back the latest event for every location. The column
3150 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3151 # combo to limit the resultset
3153 $rs = $schema->resultset('Event');
3154 $table = $rs->result_source->name;
3155 $latest = $rs->search (
3158 (SELECT e1.* FROM $table e1
3160 ON e1.location = e2.location
3161 AND e1.sequence < e2.sequence
3162 WHERE e2.sequence is NULL
3167 # Equivalent SQL (with the DBIC chunks added):
3169 SELECT me.sequence, me.location, me.type FROM
3170 (SELECT e1.* FROM events e1
3172 ON e1.location = e2.location
3173 AND e1.sequence < e2.sequence
3174 WHERE e2.sequence is NULL
3181 =item Value: ( 'update' | 'shared' )
3185 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT