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' } });
876 carp "search_like() is deprecated and will be removed in 0.09. Use search() instead.";
877 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
878 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
879 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
880 return $class->search($query, { %$attrs });
887 =item Arguments: $first, $last
889 =item Return Value: $resultset (scalar context), @row_objs (list context)
893 Returns a resultset or object list representing a subset of elements from the
894 resultset slice is called on. Indexes are from 0, i.e., to get the first
897 my ($one, $two, $three) = $rs->slice(0, 2);
902 my ($self, $min, $max) = @_;
903 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
904 $attrs->{offset} = $self->{attrs}{offset} || 0;
905 $attrs->{offset} += $min;
906 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
907 return $self->search(undef(), $attrs);
908 #my $slice = (ref $self)->new($self->result_source, $attrs);
909 #return (wantarray ? $slice->all : $slice);
916 =item Arguments: none
918 =item Return Value: $result?
922 Returns the next element in the resultset (C<undef> is there is none).
924 Can be used to efficiently iterate over records in the resultset:
926 my $rs = $schema->resultset('CD')->search;
927 while (my $cd = $rs->next) {
931 Note that you need to store the resultset object, and call C<next> on it.
932 Calling C<< resultset('Table')->next >> repeatedly will always return the
933 first record from the resultset.
939 if (my $cache = $self->get_cache) {
940 $self->{all_cache_position} ||= 0;
941 return $cache->[$self->{all_cache_position}++];
943 if ($self->{attrs}{cache}) {
944 $self->{all_cache_position} = 1;
945 return ($self->all)[0];
947 if ($self->{stashed_objects}) {
948 my $obj = shift(@{$self->{stashed_objects}});
949 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
953 exists $self->{stashed_row}
954 ? @{delete $self->{stashed_row}}
955 : $self->cursor->next
957 return undef unless (@row);
958 my ($row, @more) = $self->_construct_object(@row);
959 $self->{stashed_objects} = \@more if @more;
963 sub _construct_object {
964 my ($self, @row) = @_;
965 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
966 my @new = $self->result_class->inflate_result($self->result_source, @$info);
967 @new = $self->{_attrs}{record_filter}->(@new)
968 if exists $self->{_attrs}{record_filter};
972 sub _collapse_result {
973 my ($self, $as_proto, $row) = @_;
977 # 'foo' => [ undef, 'foo' ]
978 # 'foo.bar' => [ 'foo', 'bar' ]
979 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
981 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
983 my %collapse = %{$self->{_attrs}{collapse}||{}};
987 # if we're doing collapsing (has_many prefetch) we need to grab records
988 # until the PK changes, so fill @pri_index. if not, we leave it empty so
989 # we know we don't have to bother.
991 # the reason for not using the collapse stuff directly is because if you
992 # had for e.g. two artists in a row with no cds, the collapse info for
993 # both would be NULL (undef) so you'd lose the second artist
995 # store just the index so we can check the array positions from the row
996 # without having to contruct the full hash
998 if (keys %collapse) {
999 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1000 foreach my $i (0 .. $#construct_as) {
1001 next if defined($construct_as[$i][0]); # only self table
1002 if (delete $pri{$construct_as[$i][1]}) {
1003 push(@pri_index, $i);
1005 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1009 # no need to do an if, it'll be empty if @pri_index is empty anyway
1011 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1015 do { # no need to check anything at the front, we always want the first row
1019 foreach my $this_as (@construct_as) {
1020 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1023 push(@const_rows, \%const);
1025 } until ( # no pri_index => no collapse => drop straight out
1028 do { # get another row, stash it, drop out if different PK
1030 @copy = $self->cursor->next;
1031 $self->{stashed_row} = \@copy;
1033 # last thing in do block, counts as true if anything doesn't match
1035 # check xor defined first for NULL vs. NOT NULL then if one is
1036 # defined the other must be so check string equality
1039 (defined $pri_vals{$_} ^ defined $copy[$_])
1040 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1045 my $alias = $self->{attrs}{alias};
1052 foreach my $const (@const_rows) {
1053 scalar @const_keys or do {
1054 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1056 foreach my $key (@const_keys) {
1059 my @parts = split(/\./, $key);
1061 my $data = $const->{$key};
1062 foreach my $p (@parts) {
1063 $target = $target->[1]->{$p} ||= [];
1065 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1066 # collapsing at this point and on final part
1067 my $pos = $collapse_pos{$cur};
1068 CK: foreach my $ck (@ckey) {
1069 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1070 $collapse_pos{$cur} = $data;
1071 delete @collapse_pos{ # clear all positioning for sub-entries
1072 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1079 if (exists $collapse{$cur}) {
1080 $target = $target->[-1];
1083 $target->[0] = $data;
1085 $info->[0] = $const->{$key};
1093 =head2 result_source
1097 =item Arguments: $result_source?
1099 =item Return Value: $result_source
1103 An accessor for the primary ResultSource object from which this ResultSet
1110 =item Arguments: $result_class?
1112 =item Return Value: $result_class
1116 An accessor for the class to use when creating row objects. Defaults to
1117 C<< result_source->result_class >> - which in most cases is the name of the
1118 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1123 my ($self, $result_class) = @_;
1124 if ($result_class) {
1125 $self->ensure_class_loaded($result_class);
1126 $self->_result_class($result_class);
1128 $self->_result_class;
1135 =item Arguments: $cond, \%attrs??
1137 =item Return Value: $count
1141 Performs an SQL C<COUNT> with the same query as the resultset was built
1142 with to find the number of elements. If passed arguments, does a search
1143 on the resultset and counts the results of that.
1145 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1146 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1147 not support C<DISTINCT> with multiple columns. If you are using such a
1148 database, you should only use columns from the main table in your C<group_by>
1155 return $self->search(@_)->count if @_ and defined $_[0];
1156 return scalar @{ $self->get_cache } if $self->get_cache;
1157 my $count = $self->_count;
1158 return 0 unless $count;
1160 # need to take offset from resolved attrs
1162 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1163 $count = $self->{attrs}{rows} if
1164 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1165 $count = 0 if ($count < 0);
1169 sub _count { # Separated out so pager can get the full count
1171 my $select = { count => '*' };
1173 my $attrs = { %{$self->_resolved_attrs} };
1174 if (my $group_by = delete $attrs->{group_by}) {
1175 delete $attrs->{having};
1176 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1177 # todo: try CONCAT for multi-column pk
1178 my @pk = $self->result_source->primary_columns;
1180 my $alias = $attrs->{alias};
1181 foreach my $column (@distinct) {
1182 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1183 @distinct = ($column);
1189 $select = { count => { distinct => \@distinct } };
1192 $attrs->{select} = $select;
1193 $attrs->{as} = [qw/count/];
1195 # offset, order by and page are not needed to count. record_filter is cdbi
1196 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1198 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1199 my ($count) = $tmp_rs->cursor->next;
1207 =head2 count_literal
1211 =item Arguments: $sql_fragment, @bind_values
1213 =item Return Value: $count
1217 Counts the results in a literal query. Equivalent to calling L</search_literal>
1218 with the passed arguments, then L</count>.
1222 sub count_literal { shift->search_literal(@_)->count; }
1228 =item Arguments: none
1230 =item Return Value: @objects
1234 Returns all elements in the resultset. Called implicitly if the resultset
1235 is returned in list context.
1242 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1245 return @{ $self->get_cache } if $self->get_cache;
1249 # TODO: don't call resolve here
1250 if (keys %{$self->_resolved_attrs->{collapse}}) {
1251 # if ($self->{attrs}{prefetch}) {
1252 # Using $self->cursor->all is really just an optimisation.
1253 # If we're collapsing has_many prefetches it probably makes
1254 # very little difference, and this is cleaner than hacking
1255 # _construct_object to survive the approach
1256 my @row = $self->cursor->next;
1258 push(@obj, $self->_construct_object(@row));
1259 @row = (exists $self->{stashed_row}
1260 ? @{delete $self->{stashed_row}}
1261 : $self->cursor->next);
1264 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1267 $self->set_cache(\@obj) if $self->{attrs}{cache};
1275 =item Arguments: none
1277 =item Return Value: $self
1281 Resets the resultset's cursor, so you can iterate through the elements again.
1287 delete $self->{_attrs} if exists $self->{_attrs};
1288 $self->{all_cache_position} = 0;
1289 $self->cursor->reset;
1297 =item Arguments: none
1299 =item Return Value: $object?
1303 Resets the resultset and returns an object for the first result (if the
1304 resultset returns anything).
1309 return $_[0]->reset->next;
1312 # _cond_for_update_delete
1314 # update/delete require the condition to be modified to handle
1315 # the differing SQL syntax available. This transforms the $self->{cond}
1316 # appropriately, returning the new condition.
1318 sub _cond_for_update_delete {
1319 my ($self, $full_cond) = @_;
1322 $full_cond ||= $self->{cond};
1323 # No-op. No condition, we're updating/deleting everything
1324 return $cond unless ref $full_cond;
1326 if (ref $full_cond eq 'ARRAY') {
1330 foreach my $key (keys %{$_}) {
1332 $hash{$1} = $_->{$key};
1338 elsif (ref $full_cond eq 'HASH') {
1339 if ((keys %{$full_cond})[0] eq '-and') {
1342 my @cond = @{$full_cond->{-and}};
1343 for (my $i = 0; $i < @cond; $i++) {
1344 my $entry = $cond[$i];
1347 if (ref $entry eq 'HASH') {
1348 $hash = $self->_cond_for_update_delete($entry);
1351 $entry =~ /([^.]+)$/;
1352 $hash->{$1} = $cond[++$i];
1355 push @{$cond->{-and}}, $hash;
1359 foreach my $key (keys %{$full_cond}) {
1361 $cond->{$1} = $full_cond->{$key};
1366 $self->throw_exception(
1367 "Can't update/delete on resultset with condition unless hash or array"
1379 =item Arguments: \%values
1381 =item Return Value: $storage_rv
1385 Sets the specified columns in the resultset to the supplied values in a
1386 single query. Return value will be true if the update succeeded or false
1387 if no records were updated; exact type of success value is storage-dependent.
1392 my ($self, $values) = @_;
1393 $self->throw_exception("Values for update must be a hash")
1394 unless ref $values eq 'HASH';
1396 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1397 . ' on joined resultsets, and may affect rows well outside of the'
1398 . ' contents of $rs. Use at your own risk' )
1399 if ( $self->{attrs}{seen_join} );
1401 my $cond = $self->_cond_for_update_delete;
1403 return $self->result_source->storage->update(
1404 $self->result_source, $values, $cond
1412 =item Arguments: \%values
1414 =item Return Value: 1
1418 Fetches all objects and updates them one at a time. Note that C<update_all>
1419 will run DBIC cascade triggers, while L</update> will not.
1424 my ($self, $values) = @_;
1425 $self->throw_exception("Values for update must be a hash")
1426 unless ref $values eq 'HASH';
1427 foreach my $obj ($self->all) {
1428 $obj->set_columns($values)->update;
1437 =item Arguments: none
1439 =item Return Value: 1
1443 Deletes the contents of the resultset from its result source. Note that this
1444 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1445 to run. See also L<DBIx::Class::Row/delete>.
1447 delete may not generate correct SQL for a query with joins or a resultset
1448 chained from a related resultset. In this case it will generate a warning:-
1450 WARNING! Currently $rs->delete() does not generate proper SQL on
1451 joined resultsets, and may delete rows well outside of the contents
1452 of $rs. Use at your own risk
1454 In these cases you may find that delete_all is more appropriate, or you
1455 need to respecify your query in a way that can be expressed without a join.
1461 $self->throw_exception("Delete should not be passed any arguments")
1463 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1464 . ' on joined resultsets, and may delete rows well outside of the'
1465 . ' contents of $rs. Use at your own risk' )
1466 if ( $self->{attrs}{seen_join} );
1467 my $cond = $self->_cond_for_update_delete;
1469 $self->result_source->storage->delete($self->result_source, $cond);
1477 =item Arguments: none
1479 =item Return Value: 1
1483 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1484 will run DBIC cascade triggers, while L</delete> will not.
1490 $_->delete for $self->all;
1498 =item Arguments: \@data;
1502 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1503 For the arrayref of hashrefs style each hashref should be a structure suitable
1504 forsubmitting to a $resultset->create(...) method.
1506 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1507 to insert the data, as this is a faster method.
1509 Otherwise, each set of data is inserted into the database using
1510 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1511 objects is returned.
1513 Example: Assuming an Artist Class that has many CDs Classes relating:
1515 my $Artist_rs = $schema->resultset("Artist");
1517 ## Void Context Example
1518 $Artist_rs->populate([
1519 { artistid => 4, name => 'Manufactured Crap', cds => [
1520 { title => 'My First CD', year => 2006 },
1521 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1524 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1525 { title => 'My parents sold me to a record company' ,year => 2005 },
1526 { title => 'Why Am I So Ugly?', year => 2006 },
1527 { title => 'I Got Surgery and am now Popular', year => 2007 }
1532 ## Array Context Example
1533 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1534 { name => "Artist One"},
1535 { name => "Artist Two"},
1536 { name => "Artist Three", cds=> [
1537 { title => "First CD", year => 2007},
1538 { title => "Second CD", year => 2008},
1542 print $ArtistOne->name; ## response is 'Artist One'
1543 print $ArtistThree->cds->count ## reponse is '2'
1545 For the arrayref of arrayrefs style, the first element should be a list of the
1546 fieldsnames to which the remaining elements are rows being inserted. For
1549 $Arstist_rs->populate([
1550 [qw/artistid name/],
1551 [100, 'A Formally Unknown Singer'],
1552 [101, 'A singer that jumped the shark two albums ago'],
1553 [102, 'An actually cool singer.'],
1556 Please note an important effect on your data when choosing between void and
1557 wantarray context. Since void context goes straight to C<insert_bulk> in
1558 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1559 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1560 create primary keys for you, you will find that your PKs are empty. In this
1561 case you will have to use the wantarray context in order to create those
1567 my $self = shift @_;
1568 my $data = ref $_[0][0] eq 'HASH'
1569 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1570 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1572 if(defined wantarray) {
1574 foreach my $item (@$data) {
1575 push(@created, $self->create($item));
1579 my ($first, @rest) = @$data;
1581 my @names = grep {!ref $first->{$_}} keys %$first;
1582 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1583 my @pks = $self->result_source->primary_columns;
1585 ## do the belongs_to relationships
1586 foreach my $index (0..$#$data) {
1587 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1588 my @ret = $self->populate($data);
1592 foreach my $rel (@rels) {
1593 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1594 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1595 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1596 my $related = $result->result_source->resolve_condition(
1597 $result->result_source->relationship_info($reverse)->{cond},
1602 delete $data->[$index]->{$rel};
1603 $data->[$index] = {%{$data->[$index]}, %$related};
1605 push @names, keys %$related if $index == 0;
1609 ## do bulk insert on current row
1610 my @values = map { [ @$_{@names} ] } @$data;
1612 $self->result_source->storage->insert_bulk(
1613 $self->result_source,
1618 ## do the has_many relationships
1619 foreach my $item (@$data) {
1621 foreach my $rel (@rels) {
1622 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1624 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1625 || $self->throw_exception('Cannot find the relating object.');
1627 my $child = $parent->$rel;
1629 my $related = $child->result_source->resolve_condition(
1630 $parent->result_source->relationship_info($rel)->{cond},
1635 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1636 my @populate = map { {%$_, %$related} } @rows_to_add;
1638 $child->populate( \@populate );
1644 =head2 _normalize_populate_args ($args)
1646 Private method used by L</populate> to normalize its incoming arguments. Factored
1647 out in case you want to subclass and accept new argument structures to the
1648 L</populate> method.
1652 sub _normalize_populate_args {
1653 my ($self, $data) = @_;
1654 my @names = @{shift(@$data)};
1655 my @results_to_create;
1656 foreach my $datum (@$data) {
1657 my %result_to_create;
1658 foreach my $index (0..$#names) {
1659 $result_to_create{$names[$index]} = $$datum[$index];
1661 push @results_to_create, \%result_to_create;
1663 return \@results_to_create;
1670 =item Arguments: none
1672 =item Return Value: $pager
1676 Return Value a L<Data::Page> object for the current resultset. Only makes
1677 sense for queries with a C<page> attribute.
1679 To get the full count of entries for a paged resultset, call
1680 C<total_entries> on the L<Data::Page> object.
1686 my $attrs = $self->{attrs};
1687 $self->throw_exception("Can't create pager for non-paged rs")
1688 unless $self->{attrs}{page};
1689 $attrs->{rows} ||= 10;
1690 return $self->{pager} ||= Data::Page->new(
1691 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1698 =item Arguments: $page_number
1700 =item Return Value: $rs
1704 Returns a resultset for the $page_number page of the resultset on which page
1705 is called, where each page contains a number of rows equal to the 'rows'
1706 attribute set on the resultset (10 by default).
1711 my ($self, $page) = @_;
1712 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1719 =item Arguments: \%vals
1721 =item Return Value: $rowobject
1725 Creates a new row object in the resultset's result class and returns
1726 it. The row is not inserted into the database at this point, call
1727 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1728 will tell you whether the row object has been inserted or not.
1730 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1735 my ($self, $values) = @_;
1736 $self->throw_exception( "new_result needs a hash" )
1737 unless (ref $values eq 'HASH');
1740 my $alias = $self->{attrs}{alias};
1743 defined $self->{cond}
1744 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1746 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1747 $new{-from_resultset} = [ keys %new ] if keys %new;
1749 $self->throw_exception(
1750 "Can't abstract implicit construct, condition not a hash"
1751 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1753 my $collapsed_cond = (
1755 ? $self->_collapse_cond($self->{cond})
1759 # precendence must be given to passed values over values inherited from
1760 # the cond, so the order here is important.
1761 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1762 while( my($col,$value) = each %implied ){
1763 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1764 $new{$col} = $value->{'='};
1767 $new{$col} = $value if $self->_is_deterministic_value($value);
1773 %{ $self->_remove_alias($values, $alias) },
1774 -source_handle => $self->_source_handle,
1775 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1778 return $self->result_class->new(\%new);
1781 # _is_deterministic_value
1783 # Make an effor to strip non-deterministic values from the condition,
1784 # to make sure new_result chokes less
1786 sub _is_deterministic_value {
1789 my $ref_type = ref $value;
1790 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1791 return 1 if Scalar::Util::blessed($value);
1797 # Recursively collapse the condition.
1799 sub _collapse_cond {
1800 my ($self, $cond, $collapsed) = @_;
1804 if (ref $cond eq 'ARRAY') {
1805 foreach my $subcond (@$cond) {
1806 next unless ref $subcond; # -or
1807 # warn "ARRAY: " . Dumper $subcond;
1808 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1811 elsif (ref $cond eq 'HASH') {
1812 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1813 foreach my $subcond (@{$cond->{-and}}) {
1814 # warn "HASH: " . Dumper $subcond;
1815 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1819 # warn "LEAF: " . Dumper $cond;
1820 foreach my $col (keys %$cond) {
1821 my $value = $cond->{$col};
1822 $collapsed->{$col} = $value;
1832 # Remove the specified alias from the specified query hash. A copy is made so
1833 # the original query is not modified.
1836 my ($self, $query, $alias) = @_;
1838 my %orig = %{ $query || {} };
1841 foreach my $key (keys %orig) {
1843 $unaliased{$key} = $orig{$key};
1846 $unaliased{$1} = $orig{$key}
1847 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1853 =head2 as_query (EXPERIMENTAL)
1857 =item Arguments: none
1859 =item Return Value: \[ $sql, @bind ]
1863 Returns the SQL query and bind vars associated with the invocant.
1865 This is generally used as the RHS for a subquery.
1867 B<NOTE>: This feature is still experimental.
1871 sub as_query { return shift->cursor->as_query(@_) }
1877 =item Arguments: \%vals, \%attrs?
1879 =item Return Value: $rowobject
1883 my $artist = $schema->resultset('Artist')->find_or_new(
1884 { artist => 'fred' }, { key => 'artists' });
1886 $cd->cd_to_producer->find_or_new({ producer => $producer },
1887 { key => 'primary });
1889 Find an existing record from this resultset, based on its primary
1890 key, or a unique constraint. If none exists, instantiate a new result
1891 object and return it. The object will not be saved into your storage
1892 until you call L<DBIx::Class::Row/insert> on it.
1894 You most likely want this method when looking for existing rows using
1895 a unique constraint that is not the primary key, or looking for
1898 If you want objects to be saved immediately, use L</find_or_create> instead.
1900 B<Note>: C<find_or_new> is probably not what you want when creating a
1901 new row in a table that uses primary keys supplied by the
1902 database. Passing in a primary key column with a value of I<undef>
1903 will cause L</find> to attempt to search for a row with a value of
1910 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1911 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1912 my $exists = $self->find($hash, $attrs);
1913 return defined $exists ? $exists : $self->new_result($hash);
1920 =item Arguments: \%vals
1922 =item Return Value: a L<DBIx::Class::Row> $object
1926 Attempt to create a single new row or a row with multiple related rows
1927 in the table represented by the resultset (and related tables). This
1928 will not check for duplicate rows before inserting, use
1929 L</find_or_create> to do that.
1931 To create one row for this resultset, pass a hashref of key/value
1932 pairs representing the columns of the table and the values you wish to
1933 store. If the appropriate relationships are set up, foreign key fields
1934 can also be passed an object representing the foreign row, and the
1935 value will be set to its primary key.
1937 To create related objects, pass a hashref for the value if the related
1938 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1939 and use the name of the relationship as the key. (NOT the name of the field,
1940 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1941 of hashrefs containing the data for each of the rows to create in the foreign
1942 tables, again using the relationship name as the key.
1944 Instead of hashrefs of plain related data (key/value pairs), you may
1945 also pass new or inserted objects. New objects (not inserted yet, see
1946 L</new>), will be inserted into their appropriate tables.
1948 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1950 Example of creating a new row.
1952 $person_rs->create({
1953 name=>"Some Person",
1954 email=>"somebody@someplace.com"
1957 Example of creating a new row and also creating rows in a related C<has_many>
1958 or C<has_one> resultset. Note Arrayref.
1961 { artistid => 4, name => 'Manufactured Crap', cds => [
1962 { title => 'My First CD', year => 2006 },
1963 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1968 Example of creating a new row and also creating a row in a related
1969 C<belongs_to>resultset. Note Hashref.
1972 title=>"Music for Silly Walks",
1975 name=>"Silly Musician",
1982 my ($self, $attrs) = @_;
1983 $self->throw_exception( "create needs a hashref" )
1984 unless ref $attrs eq 'HASH';
1985 return $self->new_result($attrs)->insert;
1988 =head2 find_or_create
1992 =item Arguments: \%vals, \%attrs?
1994 =item Return Value: $rowobject
1998 $cd->cd_to_producer->find_or_create({ producer => $producer },
1999 { key => 'primary });
2001 Tries to find a record based on its primary key or unique constraints; if none
2002 is found, creates one and returns that instead.
2004 my $cd = $schema->resultset('CD')->find_or_create({
2006 artist => 'Massive Attack',
2007 title => 'Mezzanine',
2011 Also takes an optional C<key> attribute, to search by a specific key or unique
2012 constraint. For example:
2014 my $cd = $schema->resultset('CD')->find_or_create(
2016 artist => 'Massive Attack',
2017 title => 'Mezzanine',
2019 { key => 'cd_artist_title' }
2022 B<Note>: Because find_or_create() reads from the database and then
2023 possibly inserts based on the result, this method is subject to a race
2024 condition. Another process could create a record in the table after
2025 the find has completed and before the create has started. To avoid
2026 this problem, use find_or_create() inside a transaction.
2028 B<Note>: C<find_or_create> is probably not what you want when creating
2029 a new row in a table that uses primary keys supplied by the
2030 database. Passing in a primary key column with a value of I<undef>
2031 will cause L</find> to attempt to search for a row with a value of
2034 See also L</find> and L</update_or_create>. For information on how to declare
2035 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2039 sub find_or_create {
2041 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2042 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2043 my $exists = $self->find($hash, $attrs);
2044 return defined $exists ? $exists : $self->create($hash);
2047 =head2 update_or_create
2051 =item Arguments: \%col_values, { key => $unique_constraint }?
2053 =item Return Value: $rowobject
2057 $resultset->update_or_create({ col => $val, ... });
2059 First, searches for an existing row matching one of the unique constraints
2060 (including the primary key) on the source of this resultset. If a row is
2061 found, updates it with the other given column values. Otherwise, creates a new
2064 Takes an optional C<key> attribute to search on a specific unique constraint.
2067 # In your application
2068 my $cd = $schema->resultset('CD')->update_or_create(
2070 artist => 'Massive Attack',
2071 title => 'Mezzanine',
2074 { key => 'cd_artist_title' }
2077 $cd->cd_to_producer->update_or_create({
2078 producer => $producer,
2085 If no C<key> is specified, it searches on all unique constraints defined on the
2086 source, including the primary key.
2088 If the C<key> is specified as C<primary>, it searches only on the primary key.
2090 See also L</find> and L</find_or_create>. For information on how to declare
2091 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2093 B<Note>: C<update_or_create> is probably not what you want when
2094 looking for a row in a table that uses primary keys supplied by the
2095 database, unless you actually have a key value. Passing in a primary
2096 key column with a value of I<undef> will cause L</find> to attempt to
2097 search for a row with a value of I<NULL>.
2101 sub update_or_create {
2103 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2104 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2106 my $row = $self->find($cond, $attrs);
2108 $row->update($cond);
2112 return $self->create($cond);
2119 =item Arguments: none
2121 =item Return Value: \@cache_objects?
2125 Gets the contents of the cache for the resultset, if the cache is set.
2127 The cache is populated either by using the L</prefetch> attribute to
2128 L</search> or by calling L</set_cache>.
2140 =item Arguments: \@cache_objects
2142 =item Return Value: \@cache_objects
2146 Sets the contents of the cache for the resultset. Expects an arrayref
2147 of objects of the same class as those produced by the resultset. Note that
2148 if the cache is set the resultset will return the cached objects rather
2149 than re-querying the database even if the cache attr is not set.
2151 The contents of the cache can also be populated by using the
2152 L</prefetch> attribute to L</search>.
2157 my ( $self, $data ) = @_;
2158 $self->throw_exception("set_cache requires an arrayref")
2159 if defined($data) && (ref $data ne 'ARRAY');
2160 $self->{all_cache} = $data;
2167 =item Arguments: none
2169 =item Return Value: []
2173 Clears the cache for the resultset.
2178 shift->set_cache(undef);
2181 =head2 related_resultset
2185 =item Arguments: $relationship_name
2187 =item Return Value: $resultset
2191 Returns a related resultset for the supplied relationship name.
2193 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2197 sub related_resultset {
2198 my ($self, $rel) = @_;
2200 $self->{related_resultsets} ||= {};
2201 return $self->{related_resultsets}{$rel} ||= do {
2202 my $rel_obj = $self->result_source->relationship_info($rel);
2204 $self->throw_exception(
2205 "search_related: result source '" . $self->result_source->source_name .
2206 "' has no such relationship $rel")
2209 my ($from,$seen) = $self->_resolve_from($rel);
2211 my $join_count = $seen->{$rel};
2212 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2214 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2215 my %attrs = %{$self->{attrs}||{}};
2216 delete @attrs{qw(result_class alias)};
2220 if (my $cache = $self->get_cache) {
2221 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2222 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2227 my $rel_source = $self->result_source->related_source($rel);
2231 # The reason we do this now instead of passing the alias to the
2232 # search_rs below is that if you wrap/overload resultset on the
2233 # source you need to know what alias it's -going- to have for things
2234 # to work sanely (e.g. RestrictWithObject wants to be able to add
2235 # extra query restrictions, and these may need to be $alias.)
2237 my $attrs = $rel_source->resultset_attributes;
2238 local $attrs->{alias} = $alias;
2240 $rel_source->resultset
2248 where => $self->{cond},
2253 $new->set_cache($new_cache) if $new_cache;
2258 =head2 current_source_alias
2262 =item Arguments: none
2264 =item Return Value: $source_alias
2268 Returns the current table alias for the result source this resultset is built
2269 on, that will be used in the SQL query. Usually it is C<me>.
2271 Currently the source alias that refers to the result set returned by a
2272 L</search>/L</find> family method depends on how you got to the resultset: it's
2273 C<me> by default, but eg. L</search_related> aliases it to the related result
2274 source name (and keeps C<me> referring to the original result set). The long
2275 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2276 (and make this method unnecessary).
2278 Thus it's currently necessary to use this method in predefined queries (see
2279 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2280 source alias of the current result set:
2282 # in a result set class
2284 my ($self, $user) = @_;
2286 my $me = $self->current_source_alias;
2288 return $self->search(
2289 "$me.modified" => $user->id,
2295 sub current_source_alias {
2298 return ($self->{attrs} || {})->{alias} || 'me';
2302 my ($self, $extra_join) = @_;
2303 my $source = $self->result_source;
2304 my $attrs = $self->{attrs};
2306 my $from = $attrs->{from}
2307 || [ { $attrs->{alias} => $source->from } ];
2309 my $seen = { %{$attrs->{seen_join}||{}} };
2311 my $join = ($attrs->{join}
2312 ? [ $attrs->{join}, $extra_join ]
2315 # we need to take the prefetch the attrs into account before we
2316 # ->resolve_join as otherwise they get lost - captainL
2317 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2321 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2324 return ($from,$seen);
2327 sub _resolved_attrs {
2329 return $self->{_attrs} if $self->{_attrs};
2331 my $attrs = { %{ $self->{attrs} || {} } };
2332 my $source = $self->result_source;
2333 my $alias = $attrs->{alias};
2335 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2338 # build columns (as long as select isn't set) into a set of as/select hashes
2339 unless ( $attrs->{select} ) {
2341 ( ref($_) eq 'HASH' ) ? $_
2344 /^\Q${alias}.\E(.+)$/ ? $1
2346 ) => ( /\./ ? $_ : "${alias}.$_" )
2348 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2350 # add the additional columns on
2351 foreach ( 'include_columns', '+columns' ) {
2352 push @colbits, map {
2353 ( ref($_) eq 'HASH' )
2355 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2356 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2359 # start with initial select items
2360 if ( $attrs->{select} ) {
2362 ( ref $attrs->{select} eq 'ARRAY' )
2363 ? [ @{ $attrs->{select} } ]
2364 : [ $attrs->{select} ];
2368 ref $attrs->{as} eq 'ARRAY'
2369 ? [ @{ $attrs->{as} } ]
2372 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2377 # otherwise we intialise select & as to empty
2378 $attrs->{select} = [];
2382 # now add colbits to select/as
2383 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2384 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2387 if ( $adds = delete $attrs->{'+select'} ) {
2388 $adds = [$adds] unless ref $adds eq 'ARRAY';
2390 @{ $attrs->{select} },
2391 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2394 if ( $adds = delete $attrs->{'+as'} ) {
2395 $adds = [$adds] unless ref $adds eq 'ARRAY';
2396 push( @{ $attrs->{as} }, @$adds );
2399 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2401 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2402 my $join = delete $attrs->{join} || {};
2404 if ( defined $attrs->{prefetch} ) {
2405 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2409 $attrs->{from} = # have to copy here to avoid corrupting the original
2411 @{ $attrs->{from} },
2412 $source->resolve_join(
2413 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2419 $attrs->{group_by} ||= $attrs->{select}
2420 if delete $attrs->{distinct};
2421 if ( $attrs->{order_by} ) {
2422 $attrs->{order_by} = (
2423 ref( $attrs->{order_by} ) eq 'ARRAY'
2424 ? [ @{ $attrs->{order_by} } ]
2425 : [ $attrs->{order_by} ]
2429 $attrs->{order_by} = [];
2432 my $collapse = $attrs->{collapse} || {};
2433 if ( my $prefetch = delete $attrs->{prefetch} ) {
2434 $prefetch = $self->_merge_attr( {}, $prefetch );
2436 my $seen = { %{ $attrs->{seen_join} || {} } };
2437 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2439 # bring joins back to level of current class
2441 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2442 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2443 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2445 push( @{ $attrs->{order_by} }, @pre_order );
2447 $attrs->{collapse} = $collapse;
2449 if ( $attrs->{page} ) {
2450 $attrs->{offset} ||= 0;
2451 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2454 return $self->{_attrs} = $attrs;
2458 my ($self, $attr) = @_;
2460 if (ref $attr eq 'HASH') {
2461 return $self->_rollout_hash($attr);
2462 } elsif (ref $attr eq 'ARRAY') {
2463 return $self->_rollout_array($attr);
2469 sub _rollout_array {
2470 my ($self, $attr) = @_;
2473 foreach my $element (@{$attr}) {
2474 if (ref $element eq 'HASH') {
2475 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2476 } elsif (ref $element eq 'ARRAY') {
2477 # XXX - should probably recurse here
2478 push( @rolled_array, @{$self->_rollout_array($element)} );
2480 push( @rolled_array, $element );
2483 return \@rolled_array;
2487 my ($self, $attr) = @_;
2490 foreach my $key (keys %{$attr}) {
2491 push( @rolled_array, { $key => $attr->{$key} } );
2493 return \@rolled_array;
2496 sub _calculate_score {
2497 my ($self, $a, $b) = @_;
2499 if (ref $b eq 'HASH') {
2500 my ($b_key) = keys %{$b};
2501 if (ref $a eq 'HASH') {
2502 my ($a_key) = keys %{$a};
2503 if ($a_key eq $b_key) {
2504 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2509 return ($a eq $b_key) ? 1 : 0;
2512 if (ref $a eq 'HASH') {
2513 my ($a_key) = keys %{$a};
2514 return ($b eq $a_key) ? 1 : 0;
2516 return ($b eq $a) ? 1 : 0;
2522 my ($self, $orig, $import) = @_;
2524 return $import unless defined($orig);
2525 return $orig unless defined($import);
2527 $orig = $self->_rollout_attr($orig);
2528 $import = $self->_rollout_attr($import);
2531 foreach my $import_element ( @{$import} ) {
2532 # find best candidate from $orig to merge $b_element into
2533 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2534 foreach my $orig_element ( @{$orig} ) {
2535 my $score = $self->_calculate_score( $orig_element, $import_element );
2536 if ($score > $best_candidate->{score}) {
2537 $best_candidate->{position} = $position;
2538 $best_candidate->{score} = $score;
2542 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2544 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2545 push( @{$orig}, $import_element );
2547 my $orig_best = $orig->[$best_candidate->{position}];
2548 # merge orig_best and b_element together and replace original with merged
2549 if (ref $orig_best ne 'HASH') {
2550 $orig->[$best_candidate->{position}] = $import_element;
2551 } elsif (ref $import_element eq 'HASH') {
2552 my ($key) = keys %{$orig_best};
2553 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2556 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2566 $self->_source_handle($_[0]->handle);
2568 $self->_source_handle->resolve;
2572 =head2 throw_exception
2574 See L<DBIx::Class::Schema/throw_exception> for details.
2578 sub throw_exception {
2580 if (ref $self && $self->_source_handle->schema) {
2581 $self->_source_handle->schema->throw_exception(@_)
2588 # XXX: FIXME: Attributes docs need clearing up
2592 Attributes are used to refine a ResultSet in various ways when
2593 searching for data. They can be passed to any method which takes an
2594 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2597 These are in no particular order:
2603 =item Value: ( $order_by | \@order_by | \%order_by )
2607 Which column(s) to order the results by. If a single column name, or
2608 an arrayref of names is supplied, the argument is passed through
2609 directly to SQL. The hashref syntax allows for connection-agnostic
2610 specification of ordering direction:
2612 For descending order:
2614 order_by => { -desc => [qw/col1 col2 col3/] }
2616 For explicit ascending order:
2618 order_by => { -asc => 'col' }
2620 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2621 supported, although you are strongly encouraged to use the hashref
2622 syntax as outlined above.
2628 =item Value: \@columns
2632 Shortcut to request a particular set of columns to be retrieved. Each
2633 column spec may be a string (a table column name), or a hash (in which
2634 case the key is the C<as> value, and the value is used as the C<select>
2635 expression). Adds C<me.> onto the start of any column without a C<.> in
2636 it and sets C<select> from that, then auto-populates C<as> from
2637 C<select> as normal. (You may also use the C<cols> attribute, as in
2638 earlier versions of DBIC.)
2644 =item Value: \@columns
2648 Indicates additional columns to be selected from storage. Works the same
2649 as L</columns> but adds columns to the selection. (You may also use the
2650 C<include_columns> attribute, as in earlier versions of DBIC). For
2653 $schema->resultset('CD')->search(undef, {
2654 '+columns' => ['artist.name'],
2658 would return all CDs and include a 'name' column to the information
2659 passed to object inflation. Note that the 'artist' is the name of the
2660 column (or relationship) accessor, and 'name' is the name of the column
2661 accessor in the related table.
2663 =head2 include_columns
2667 =item Value: \@columns
2671 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2677 =item Value: \@select_columns
2681 Indicates which columns should be selected from the storage. You can use
2682 column names, or in the case of RDBMS back ends, function or stored procedure
2685 $rs = $schema->resultset('Employee')->search(undef, {
2688 { count => 'employeeid' },
2693 When you use function/stored procedure names and do not supply an C<as>
2694 attribute, the column names returned are storage-dependent. E.g. MySQL would
2695 return a column named C<count(employeeid)> in the above example.
2701 Indicates additional columns to be selected from storage. Works the same as
2702 L</select> but adds columns to the selection.
2710 Indicates additional column names for those added via L</+select>. See L</as>.
2718 =item Value: \@inflation_names
2722 Indicates column names for object inflation. That is, C<as>
2723 indicates the name that the column can be accessed as via the
2724 C<get_column> method (or via the object accessor, B<if one already
2725 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2727 The C<as> attribute is used in conjunction with C<select>,
2728 usually when C<select> contains one or more function or stored
2731 $rs = $schema->resultset('Employee')->search(undef, {
2734 { count => 'employeeid' }
2736 as => ['name', 'employee_count'],
2739 my $employee = $rs->first(); # get the first Employee
2741 If the object against which the search is performed already has an accessor
2742 matching a column name specified in C<as>, the value can be retrieved using
2743 the accessor as normal:
2745 my $name = $employee->name();
2747 If on the other hand an accessor does not exist in the object, you need to
2748 use C<get_column> instead:
2750 my $employee_count = $employee->get_column('employee_count');
2752 You can create your own accessors if required - see
2753 L<DBIx::Class::Manual::Cookbook> for details.
2755 Please note: This will NOT insert an C<AS employee_count> into the SQL
2756 statement produced, it is used for internal access only. Thus
2757 attempting to use the accessor in an C<order_by> clause or similar
2758 will fail miserably.
2760 To get around this limitation, you can supply literal SQL to your
2761 C<select> attibute that contains the C<AS alias> text, eg:
2763 select => [\'myfield AS alias']
2769 =item Value: ($rel_name | \@rel_names | \%rel_names)
2773 Contains a list of relationships that should be joined for this query. For
2776 # Get CDs by Nine Inch Nails
2777 my $rs = $schema->resultset('CD')->search(
2778 { 'artist.name' => 'Nine Inch Nails' },
2779 { join => 'artist' }
2782 Can also contain a hash reference to refer to the other relation's relations.
2785 package MyApp::Schema::Track;
2786 use base qw/DBIx::Class/;
2787 __PACKAGE__->table('track');
2788 __PACKAGE__->add_columns(qw/trackid cd position title/);
2789 __PACKAGE__->set_primary_key('trackid');
2790 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2793 # In your application
2794 my $rs = $schema->resultset('Artist')->search(
2795 { 'track.title' => 'Teardrop' },
2797 join => { cd => 'track' },
2798 order_by => 'artist.name',
2802 You need to use the relationship (not the table) name in conditions,
2803 because they are aliased as such. The current table is aliased as "me", so
2804 you need to use me.column_name in order to avoid ambiguity. For example:
2806 # Get CDs from 1984 with a 'Foo' track
2807 my $rs = $schema->resultset('CD')->search(
2810 'tracks.name' => 'Foo'
2812 { join => 'tracks' }
2815 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2816 similarly for a third time). For e.g.
2818 my $rs = $schema->resultset('Artist')->search({
2819 'cds.title' => 'Down to Earth',
2820 'cds_2.title' => 'Popular',
2822 join => [ qw/cds cds/ ],
2825 will return a set of all artists that have both a cd with title 'Down
2826 to Earth' and a cd with title 'Popular'.
2828 If you want to fetch related objects from other tables as well, see C<prefetch>
2831 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2837 =item Value: ($rel_name | \@rel_names | \%rel_names)
2841 Contains one or more relationships that should be fetched along with
2842 the main query (when they are accessed afterwards the data will
2843 already be available, without extra queries to the database). This is
2844 useful for when you know you will need the related objects, because it
2845 saves at least one query:
2847 my $rs = $schema->resultset('Tag')->search(
2856 The initial search results in SQL like the following:
2858 SELECT tag.*, cd.*, artist.* FROM tag
2859 JOIN cd ON tag.cd = cd.cdid
2860 JOIN artist ON cd.artist = artist.artistid
2862 L<DBIx::Class> has no need to go back to the database when we access the
2863 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2866 Simple prefetches will be joined automatically, so there is no need
2867 for a C<join> attribute in the above search.
2869 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2870 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2871 with an accessor type of 'single' or 'filter'). A more complex example that
2872 prefetches an artists cds, the tracks on those cds, and the tags associted
2873 with that artist is given below (assuming many-to-many from artists to tags):
2875 my $rs = $schema->resultset('Artist')->search(
2879 { cds => 'tracks' },
2880 { artist_tags => 'tags' }
2886 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2887 attributes will be ignored.
2897 Makes the resultset paged and specifies the page to retrieve. Effectively
2898 identical to creating a non-pages resultset and then calling ->page($page)
2901 If L<rows> attribute is not specified it defualts to 10 rows per page.
2903 When you have a paged resultset, L</count> will only return the number
2904 of rows in the page. To get the total, use the L</pager> and call
2905 C<total_entries> on it.
2915 Specifes the maximum number of rows for direct retrieval or the number of
2916 rows per page if the page attribute or method is used.
2922 =item Value: $offset
2926 Specifies the (zero-based) row number for the first row to be returned, or the
2927 of the first row of the first page if paging is used.
2933 =item Value: \@columns
2937 A arrayref of columns to group by. Can include columns of joined tables.
2939 group_by => [qw/ column1 column2 ... /]
2945 =item Value: $condition
2949 HAVING is a select statement attribute that is applied between GROUP BY and
2950 ORDER BY. It is applied to the after the grouping calculations have been
2953 having => { 'count(employee)' => { '>=', 100 } }
2959 =item Value: (0 | 1)
2963 Set to 1 to group by all columns.
2969 Adds to the WHERE clause.
2971 # only return rows WHERE deleted IS NULL for all searches
2972 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2974 Can be overridden by passing C<{ where => undef }> as an attribute
2981 Set to 1 to cache search results. This prevents extra SQL queries if you
2982 revisit rows in your ResultSet:
2984 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2986 while( my $artist = $resultset->next ) {
2990 $rs->first; # without cache, this would issue a query
2992 By default, searches are not cached.
2994 For more examples of using these attributes, see
2995 L<DBIx::Class::Manual::Cookbook>.
3001 =item Value: \@from_clause
3005 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3006 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3009 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3011 C<join> will usually do what you need and it is strongly recommended that you
3012 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3013 And we really do mean "cannot", not just tried and failed. Attempting to use
3014 this because you're having problems with C<join> is like trying to use x86
3015 ASM because you've got a syntax error in your C. Trust us on this.
3017 Now, if you're still really, really sure you need to use this (and if you're
3018 not 100% sure, ask the mailing list first), here's an explanation of how this
3021 The syntax is as follows -
3024 { <alias1> => <table1> },
3026 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3027 [], # nested JOIN (optional)
3028 { <table1.column1> => <table2.column2>, ... (more conditions) },
3030 # More of the above [ ] may follow for additional joins
3037 ON <table1.column1> = <table2.column2>
3038 <more joins may follow>
3040 An easy way to follow the examples below is to remember the following:
3042 Anything inside "[]" is a JOIN
3043 Anything inside "{}" is a condition for the enclosing JOIN
3045 The following examples utilize a "person" table in a family tree application.
3046 In order to express parent->child relationships, this table is self-joined:
3048 # Person->belongs_to('father' => 'Person');
3049 # Person->belongs_to('mother' => 'Person');
3051 C<from> can be used to nest joins. Here we return all children with a father,
3052 then search against all mothers of those children:
3054 $rs = $schema->resultset('Person')->search(
3057 alias => 'mother', # alias columns in accordance with "from"
3059 { mother => 'person' },
3062 { child => 'person' },
3064 { father => 'person' },
3065 { 'father.person_id' => 'child.father_id' }
3068 { 'mother.person_id' => 'child.mother_id' }
3075 # SELECT mother.* FROM person mother
3078 # JOIN person father
3079 # ON ( father.person_id = child.father_id )
3081 # ON ( mother.person_id = child.mother_id )
3083 The type of any join can be controlled manually. To search against only people
3084 with a father in the person table, we could explicitly use C<INNER JOIN>:
3086 $rs = $schema->resultset('Person')->search(
3089 alias => 'child', # alias columns in accordance with "from"
3091 { child => 'person' },
3093 { father => 'person', -join_type => 'inner' },
3094 { 'father.id' => 'child.father_id' }
3101 # SELECT child.* FROM person child
3102 # INNER JOIN person father ON child.father_id = father.id
3104 If you need to express really complex joins or you need a subselect, you
3105 can supply literal SQL to C<from> via a scalar reference. In this case
3106 the contents of the scalar will replace the table name asscoiated with the
3109 WARNING: This technique might very well not work as expected on chained
3110 searches - you have been warned.
3112 # Assuming the Event resultsource is defined as:
3114 MySchema::Event->add_columns (
3117 is_auto_increment => 1,
3126 MySchema::Event->set_primary_key ('sequence');
3128 # This will get back the latest event for every location. The column
3129 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3130 # combo to limit the resultset
3132 $rs = $schema->resultset('Event');
3133 $table = $rs->result_source->name;
3134 $latest = $rs->search (
3137 (SELECT e1.* FROM $table e1
3139 ON e1.location = e2.location
3140 AND e1.sequence < e2.sequence
3141 WHERE e2.sequence is NULL
3146 # Equivalent SQL (with the DBIC chunks added):
3148 SELECT me.sequence, me.location, me.type FROM
3149 (SELECT e1.* FROM events e1
3151 ON e1.location = e2.location
3152 AND e1.sequence < e2.sequence
3153 WHERE e2.sequence is NULL
3160 =item Value: ( 'update' | 'shared' )
3164 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT