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>.
867 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
868 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
869 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
870 return $class->search($query, { %$attrs });
877 =item Arguments: $first, $last
879 =item Return Value: $resultset (scalar context), @row_objs (list context)
883 Returns a resultset or object list representing a subset of elements from the
884 resultset slice is called on. Indexes are from 0, i.e., to get the first
887 my ($one, $two, $three) = $rs->slice(0, 2);
892 my ($self, $min, $max) = @_;
893 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
894 $attrs->{offset} = $self->{attrs}{offset} || 0;
895 $attrs->{offset} += $min;
896 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
897 return $self->search(undef(), $attrs);
898 #my $slice = (ref $self)->new($self->result_source, $attrs);
899 #return (wantarray ? $slice->all : $slice);
906 =item Arguments: none
908 =item Return Value: $result?
912 Returns the next element in the resultset (C<undef> is there is none).
914 Can be used to efficiently iterate over records in the resultset:
916 my $rs = $schema->resultset('CD')->search;
917 while (my $cd = $rs->next) {
921 Note that you need to store the resultset object, and call C<next> on it.
922 Calling C<< resultset('Table')->next >> repeatedly will always return the
923 first record from the resultset.
929 if (my $cache = $self->get_cache) {
930 $self->{all_cache_position} ||= 0;
931 return $cache->[$self->{all_cache_position}++];
933 if ($self->{attrs}{cache}) {
934 $self->{all_cache_position} = 1;
935 return ($self->all)[0];
937 if ($self->{stashed_objects}) {
938 my $obj = shift(@{$self->{stashed_objects}});
939 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
943 exists $self->{stashed_row}
944 ? @{delete $self->{stashed_row}}
945 : $self->cursor->next
947 return undef unless (@row);
948 my ($row, @more) = $self->_construct_object(@row);
949 $self->{stashed_objects} = \@more if @more;
953 sub _construct_object {
954 my ($self, @row) = @_;
955 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
956 my @new = $self->result_class->inflate_result($self->result_source, @$info);
957 @new = $self->{_attrs}{record_filter}->(@new)
958 if exists $self->{_attrs}{record_filter};
962 sub _collapse_result {
963 my ($self, $as_proto, $row) = @_;
967 # 'foo' => [ undef, 'foo' ]
968 # 'foo.bar' => [ 'foo', 'bar' ]
969 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
971 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
973 my %collapse = %{$self->{_attrs}{collapse}||{}};
977 # if we're doing collapsing (has_many prefetch) we need to grab records
978 # until the PK changes, so fill @pri_index. if not, we leave it empty so
979 # we know we don't have to bother.
981 # the reason for not using the collapse stuff directly is because if you
982 # had for e.g. two artists in a row with no cds, the collapse info for
983 # both would be NULL (undef) so you'd lose the second artist
985 # store just the index so we can check the array positions from the row
986 # without having to contruct the full hash
988 if (keys %collapse) {
989 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
990 foreach my $i (0 .. $#construct_as) {
991 next if defined($construct_as[$i][0]); # only self table
992 if (delete $pri{$construct_as[$i][1]}) {
993 push(@pri_index, $i);
995 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
999 # no need to do an if, it'll be empty if @pri_index is empty anyway
1001 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1005 do { # no need to check anything at the front, we always want the first row
1009 foreach my $this_as (@construct_as) {
1010 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1013 push(@const_rows, \%const);
1015 } until ( # no pri_index => no collapse => drop straight out
1018 do { # get another row, stash it, drop out if different PK
1020 @copy = $self->cursor->next;
1021 $self->{stashed_row} = \@copy;
1023 # last thing in do block, counts as true if anything doesn't match
1025 # check xor defined first for NULL vs. NOT NULL then if one is
1026 # defined the other must be so check string equality
1029 (defined $pri_vals{$_} ^ defined $copy[$_])
1030 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1035 my $alias = $self->{attrs}{alias};
1042 foreach my $const (@const_rows) {
1043 scalar @const_keys or do {
1044 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1046 foreach my $key (@const_keys) {
1049 my @parts = split(/\./, $key);
1051 my $data = $const->{$key};
1052 foreach my $p (@parts) {
1053 $target = $target->[1]->{$p} ||= [];
1055 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1056 # collapsing at this point and on final part
1057 my $pos = $collapse_pos{$cur};
1058 CK: foreach my $ck (@ckey) {
1059 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1060 $collapse_pos{$cur} = $data;
1061 delete @collapse_pos{ # clear all positioning for sub-entries
1062 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1069 if (exists $collapse{$cur}) {
1070 $target = $target->[-1];
1073 $target->[0] = $data;
1075 $info->[0] = $const->{$key};
1083 =head2 result_source
1087 =item Arguments: $result_source?
1089 =item Return Value: $result_source
1093 An accessor for the primary ResultSource object from which this ResultSet
1100 =item Arguments: $result_class?
1102 =item Return Value: $result_class
1106 An accessor for the class to use when creating row objects. Defaults to
1107 C<< result_source->result_class >> - which in most cases is the name of the
1108 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1113 my ($self, $result_class) = @_;
1114 if ($result_class) {
1115 $self->ensure_class_loaded($result_class);
1116 $self->_result_class($result_class);
1118 $self->_result_class;
1125 =item Arguments: $cond, \%attrs??
1127 =item Return Value: $count
1131 Performs an SQL C<COUNT> with the same query as the resultset was built
1132 with to find the number of elements. If passed arguments, does a search
1133 on the resultset and counts the results of that.
1135 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1136 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1137 not support C<DISTINCT> with multiple columns. If you are using such a
1138 database, you should only use columns from the main table in your C<group_by>
1145 return $self->search(@_)->count if @_ and defined $_[0];
1146 return scalar @{ $self->get_cache } if $self->get_cache;
1147 my $count = $self->_count;
1148 return 0 unless $count;
1150 # need to take offset from resolved attrs
1152 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1153 $count = $self->{attrs}{rows} if
1154 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1155 $count = 0 if ($count < 0);
1159 sub _count { # Separated out so pager can get the full count
1161 my $select = { count => '*' };
1163 my $attrs = { %{$self->_resolved_attrs} };
1164 if (my $group_by = delete $attrs->{group_by}) {
1165 delete $attrs->{having};
1166 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1167 # todo: try CONCAT for multi-column pk
1168 my @pk = $self->result_source->primary_columns;
1170 my $alias = $attrs->{alias};
1171 foreach my $column (@distinct) {
1172 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1173 @distinct = ($column);
1179 $select = { count => { distinct => \@distinct } };
1182 $attrs->{select} = $select;
1183 $attrs->{as} = [qw/count/];
1185 # offset, order by and page are not needed to count. record_filter is cdbi
1186 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1188 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1189 my ($count) = $tmp_rs->cursor->next;
1197 =head2 count_literal
1201 =item Arguments: $sql_fragment, @bind_values
1203 =item Return Value: $count
1207 Counts the results in a literal query. Equivalent to calling L</search_literal>
1208 with the passed arguments, then L</count>.
1212 sub count_literal { shift->search_literal(@_)->count; }
1218 =item Arguments: none
1220 =item Return Value: @objects
1224 Returns all elements in the resultset. Called implicitly if the resultset
1225 is returned in list context.
1232 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1235 return @{ $self->get_cache } if $self->get_cache;
1239 # TODO: don't call resolve here
1240 if (keys %{$self->_resolved_attrs->{collapse}}) {
1241 # if ($self->{attrs}{prefetch}) {
1242 # Using $self->cursor->all is really just an optimisation.
1243 # If we're collapsing has_many prefetches it probably makes
1244 # very little difference, and this is cleaner than hacking
1245 # _construct_object to survive the approach
1246 my @row = $self->cursor->next;
1248 push(@obj, $self->_construct_object(@row));
1249 @row = (exists $self->{stashed_row}
1250 ? @{delete $self->{stashed_row}}
1251 : $self->cursor->next);
1254 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1257 $self->set_cache(\@obj) if $self->{attrs}{cache};
1265 =item Arguments: none
1267 =item Return Value: $self
1271 Resets the resultset's cursor, so you can iterate through the elements again.
1277 delete $self->{_attrs} if exists $self->{_attrs};
1278 $self->{all_cache_position} = 0;
1279 $self->cursor->reset;
1287 =item Arguments: none
1289 =item Return Value: $object?
1293 Resets the resultset and returns an object for the first result (if the
1294 resultset returns anything).
1299 return $_[0]->reset->next;
1302 # _cond_for_update_delete
1304 # update/delete require the condition to be modified to handle
1305 # the differing SQL syntax available. This transforms the $self->{cond}
1306 # appropriately, returning the new condition.
1308 sub _cond_for_update_delete {
1309 my ($self, $full_cond) = @_;
1312 $full_cond ||= $self->{cond};
1313 # No-op. No condition, we're updating/deleting everything
1314 return $cond unless ref $full_cond;
1316 if (ref $full_cond eq 'ARRAY') {
1320 foreach my $key (keys %{$_}) {
1322 $hash{$1} = $_->{$key};
1328 elsif (ref $full_cond eq 'HASH') {
1329 if ((keys %{$full_cond})[0] eq '-and') {
1332 my @cond = @{$full_cond->{-and}};
1333 for (my $i = 0; $i < @cond; $i++) {
1334 my $entry = $cond[$i];
1337 if (ref $entry eq 'HASH') {
1338 $hash = $self->_cond_for_update_delete($entry);
1341 $entry =~ /([^.]+)$/;
1342 $hash->{$1} = $cond[++$i];
1345 push @{$cond->{-and}}, $hash;
1349 foreach my $key (keys %{$full_cond}) {
1351 $cond->{$1} = $full_cond->{$key};
1356 $self->throw_exception(
1357 "Can't update/delete on resultset with condition unless hash or array"
1369 =item Arguments: \%values
1371 =item Return Value: $storage_rv
1375 Sets the specified columns in the resultset to the supplied values in a
1376 single query. Return value will be true if the update succeeded or false
1377 if no records were updated; exact type of success value is storage-dependent.
1382 my ($self, $values) = @_;
1383 $self->throw_exception("Values for update must be a hash")
1384 unless ref $values eq 'HASH';
1386 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1387 . ' on joined resultsets, and may affect rows well outside of the'
1388 . ' contents of $rs. Use at your own risk' )
1389 if ( $self->{attrs}{seen_join} );
1391 my $cond = $self->_cond_for_update_delete;
1393 return $self->result_source->storage->update(
1394 $self->result_source, $values, $cond
1402 =item Arguments: \%values
1404 =item Return Value: 1
1408 Fetches all objects and updates them one at a time. Note that C<update_all>
1409 will run DBIC cascade triggers, while L</update> will not.
1414 my ($self, $values) = @_;
1415 $self->throw_exception("Values for update must be a hash")
1416 unless ref $values eq 'HASH';
1417 foreach my $obj ($self->all) {
1418 $obj->set_columns($values)->update;
1427 =item Arguments: none
1429 =item Return Value: 1
1433 Deletes the contents of the resultset from its result source. Note that this
1434 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1435 to run. See also L<DBIx::Class::Row/delete>.
1437 delete may not generate correct SQL for a query with joins or a resultset
1438 chained from a related resultset. In this case it will generate a warning:-
1440 WARNING! Currently $rs->delete() does not generate proper SQL on
1441 joined resultsets, and may delete rows well outside of the contents
1442 of $rs. Use at your own risk
1444 In these cases you may find that delete_all is more appropriate, or you
1445 need to respecify your query in a way that can be expressed without a join.
1451 $self->throw_exception("Delete should not be passed any arguments")
1453 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1454 . ' on joined resultsets, and may delete rows well outside of the'
1455 . ' contents of $rs. Use at your own risk' )
1456 if ( $self->{attrs}{seen_join} );
1457 my $cond = $self->_cond_for_update_delete;
1459 $self->result_source->storage->delete($self->result_source, $cond);
1467 =item Arguments: none
1469 =item Return Value: 1
1473 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1474 will run DBIC cascade triggers, while L</delete> will not.
1480 $_->delete for $self->all;
1488 =item Arguments: \@data;
1492 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1493 For the arrayref of hashrefs style each hashref should be a structure suitable
1494 forsubmitting to a $resultset->create(...) method.
1496 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1497 to insert the data, as this is a faster method.
1499 Otherwise, each set of data is inserted into the database using
1500 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1501 objects is returned.
1503 Example: Assuming an Artist Class that has many CDs Classes relating:
1505 my $Artist_rs = $schema->resultset("Artist");
1507 ## Void Context Example
1508 $Artist_rs->populate([
1509 { artistid => 4, name => 'Manufactured Crap', cds => [
1510 { title => 'My First CD', year => 2006 },
1511 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1514 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1515 { title => 'My parents sold me to a record company' ,year => 2005 },
1516 { title => 'Why Am I So Ugly?', year => 2006 },
1517 { title => 'I Got Surgery and am now Popular', year => 2007 }
1522 ## Array Context Example
1523 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1524 { name => "Artist One"},
1525 { name => "Artist Two"},
1526 { name => "Artist Three", cds=> [
1527 { title => "First CD", year => 2007},
1528 { title => "Second CD", year => 2008},
1532 print $ArtistOne->name; ## response is 'Artist One'
1533 print $ArtistThree->cds->count ## reponse is '2'
1535 For the arrayref of arrayrefs style, the first element should be a list of the
1536 fieldsnames to which the remaining elements are rows being inserted. For
1539 $Arstist_rs->populate([
1540 [qw/artistid name/],
1541 [100, 'A Formally Unknown Singer'],
1542 [101, 'A singer that jumped the shark two albums ago'],
1543 [102, 'An actually cool singer.'],
1546 Please note an important effect on your data when choosing between void and
1547 wantarray context. Since void context goes straight to C<insert_bulk> in
1548 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1549 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1550 create primary keys for you, you will find that your PKs are empty. In this
1551 case you will have to use the wantarray context in order to create those
1557 my $self = shift @_;
1558 my $data = ref $_[0][0] eq 'HASH'
1559 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1560 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1562 if(defined wantarray) {
1564 foreach my $item (@$data) {
1565 push(@created, $self->create($item));
1569 my ($first, @rest) = @$data;
1571 my @names = grep {!ref $first->{$_}} keys %$first;
1572 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1573 my @pks = $self->result_source->primary_columns;
1575 ## do the belongs_to relationships
1576 foreach my $index (0..$#$data) {
1577 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1578 my @ret = $self->populate($data);
1582 foreach my $rel (@rels) {
1583 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1584 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1585 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1586 my $related = $result->result_source->resolve_condition(
1587 $result->result_source->relationship_info($reverse)->{cond},
1592 delete $data->[$index]->{$rel};
1593 $data->[$index] = {%{$data->[$index]}, %$related};
1595 push @names, keys %$related if $index == 0;
1599 ## do bulk insert on current row
1600 my @values = map { [ @$_{@names} ] } @$data;
1602 $self->result_source->storage->insert_bulk(
1603 $self->result_source,
1608 ## do the has_many relationships
1609 foreach my $item (@$data) {
1611 foreach my $rel (@rels) {
1612 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1614 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1615 || $self->throw_exception('Cannot find the relating object.');
1617 my $child = $parent->$rel;
1619 my $related = $child->result_source->resolve_condition(
1620 $parent->result_source->relationship_info($rel)->{cond},
1625 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1626 my @populate = map { {%$_, %$related} } @rows_to_add;
1628 $child->populate( \@populate );
1634 =head2 _normalize_populate_args ($args)
1636 Private method used by L</populate> to normalize its incoming arguments. Factored
1637 out in case you want to subclass and accept new argument structures to the
1638 L</populate> method.
1642 sub _normalize_populate_args {
1643 my ($self, $data) = @_;
1644 my @names = @{shift(@$data)};
1645 my @results_to_create;
1646 foreach my $datum (@$data) {
1647 my %result_to_create;
1648 foreach my $index (0..$#names) {
1649 $result_to_create{$names[$index]} = $$datum[$index];
1651 push @results_to_create, \%result_to_create;
1653 return \@results_to_create;
1660 =item Arguments: none
1662 =item Return Value: $pager
1666 Return Value a L<Data::Page> object for the current resultset. Only makes
1667 sense for queries with a C<page> attribute.
1669 To get the full count of entries for a paged resultset, call
1670 C<total_entries> on the L<Data::Page> object.
1676 my $attrs = $self->{attrs};
1677 $self->throw_exception("Can't create pager for non-paged rs")
1678 unless $self->{attrs}{page};
1679 $attrs->{rows} ||= 10;
1680 return $self->{pager} ||= Data::Page->new(
1681 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1688 =item Arguments: $page_number
1690 =item Return Value: $rs
1694 Returns a resultset for the $page_number page of the resultset on which page
1695 is called, where each page contains a number of rows equal to the 'rows'
1696 attribute set on the resultset (10 by default).
1701 my ($self, $page) = @_;
1702 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1709 =item Arguments: \%vals
1711 =item Return Value: $rowobject
1715 Creates a new row object in the resultset's result class and returns
1716 it. The row is not inserted into the database at this point, call
1717 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1718 will tell you whether the row object has been inserted or not.
1720 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1725 my ($self, $values) = @_;
1726 $self->throw_exception( "new_result needs a hash" )
1727 unless (ref $values eq 'HASH');
1730 my $alias = $self->{attrs}{alias};
1733 defined $self->{cond}
1734 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1736 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1737 $new{-from_resultset} = [ keys %new ] if keys %new;
1739 $self->throw_exception(
1740 "Can't abstract implicit construct, condition not a hash"
1741 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1743 my $collapsed_cond = (
1745 ? $self->_collapse_cond($self->{cond})
1749 # precendence must be given to passed values over values inherited from
1750 # the cond, so the order here is important.
1751 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1752 while( my($col,$value) = each %implied ){
1753 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1754 $new{$col} = $value->{'='};
1757 $new{$col} = $value if $self->_is_deterministic_value($value);
1763 %{ $self->_remove_alias($values, $alias) },
1764 -source_handle => $self->_source_handle,
1765 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1768 return $self->result_class->new(\%new);
1771 # _is_deterministic_value
1773 # Make an effor to strip non-deterministic values from the condition,
1774 # to make sure new_result chokes less
1776 sub _is_deterministic_value {
1779 my $ref_type = ref $value;
1780 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1781 return 1 if Scalar::Util::blessed($value);
1787 # Recursively collapse the condition.
1789 sub _collapse_cond {
1790 my ($self, $cond, $collapsed) = @_;
1794 if (ref $cond eq 'ARRAY') {
1795 foreach my $subcond (@$cond) {
1796 next unless ref $subcond; # -or
1797 # warn "ARRAY: " . Dumper $subcond;
1798 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1801 elsif (ref $cond eq 'HASH') {
1802 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1803 foreach my $subcond (@{$cond->{-and}}) {
1804 # warn "HASH: " . Dumper $subcond;
1805 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1809 # warn "LEAF: " . Dumper $cond;
1810 foreach my $col (keys %$cond) {
1811 my $value = $cond->{$col};
1812 $collapsed->{$col} = $value;
1822 # Remove the specified alias from the specified query hash. A copy is made so
1823 # the original query is not modified.
1826 my ($self, $query, $alias) = @_;
1828 my %orig = %{ $query || {} };
1831 foreach my $key (keys %orig) {
1833 $unaliased{$key} = $orig{$key};
1836 $unaliased{$1} = $orig{$key}
1837 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1843 =head2 as_query (EXPERIMENTAL)
1847 =item Arguments: none
1849 =item Return Value: \[ $sql, @bind ]
1853 Returns the SQL query and bind vars associated with the invocant.
1855 This is generally used as the RHS for a subquery.
1857 B<NOTE>: This feature is still experimental.
1861 sub as_query { return shift->cursor->as_query(@_) }
1867 =item Arguments: \%vals, \%attrs?
1869 =item Return Value: $rowobject
1873 my $artist = $schema->resultset('Artist')->find_or_new(
1874 { artist => 'fred' }, { key => 'artists' });
1876 $cd->cd_to_producer->find_or_new({ producer => $producer },
1877 { key => 'primary });
1879 Find an existing record from this resultset, based on its primary
1880 key, or a unique constraint. If none exists, instantiate a new result
1881 object and return it. The object will not be saved into your storage
1882 until you call L<DBIx::Class::Row/insert> on it.
1884 You most likely want this method when looking for existing rows using
1885 a unique constraint that is not the primary key, or looking for
1888 If you want objects to be saved immediately, use L</find_or_create> instead.
1890 B<Note>: C<find_or_new> is probably not what you want when creating a
1891 new row in a table that uses primary keys supplied by the
1892 database. Passing in a primary key column with a value of I<undef>
1893 will cause L</find> to attempt to search for a row with a value of
1900 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1901 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1902 my $exists = $self->find($hash, $attrs);
1903 return defined $exists ? $exists : $self->new_result($hash);
1910 =item Arguments: \%vals
1912 =item Return Value: a L<DBIx::Class::Row> $object
1916 Attempt to create a single new row or a row with multiple related rows
1917 in the table represented by the resultset (and related tables). This
1918 will not check for duplicate rows before inserting, use
1919 L</find_or_create> to do that.
1921 To create one row for this resultset, pass a hashref of key/value
1922 pairs representing the columns of the table and the values you wish to
1923 store. If the appropriate relationships are set up, foreign key fields
1924 can also be passed an object representing the foreign row, and the
1925 value will be set to its primary key.
1927 To create related objects, pass a hashref for the value if the related
1928 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1929 and use the name of the relationship as the key. (NOT the name of the field,
1930 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1931 of hashrefs containing the data for each of the rows to create in the foreign
1932 tables, again using the relationship name as the key.
1934 Instead of hashrefs of plain related data (key/value pairs), you may
1935 also pass new or inserted objects. New objects (not inserted yet, see
1936 L</new>), will be inserted into their appropriate tables.
1938 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1940 Example of creating a new row.
1942 $person_rs->create({
1943 name=>"Some Person",
1944 email=>"somebody@someplace.com"
1947 Example of creating a new row and also creating rows in a related C<has_many>
1948 or C<has_one> resultset. Note Arrayref.
1951 { artistid => 4, name => 'Manufactured Crap', cds => [
1952 { title => 'My First CD', year => 2006 },
1953 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1958 Example of creating a new row and also creating a row in a related
1959 C<belongs_to>resultset. Note Hashref.
1962 title=>"Music for Silly Walks",
1965 name=>"Silly Musician",
1972 my ($self, $attrs) = @_;
1973 $self->throw_exception( "create needs a hashref" )
1974 unless ref $attrs eq 'HASH';
1975 return $self->new_result($attrs)->insert;
1978 =head2 find_or_create
1982 =item Arguments: \%vals, \%attrs?
1984 =item Return Value: $rowobject
1988 $cd->cd_to_producer->find_or_create({ producer => $producer },
1989 { key => 'primary });
1991 Tries to find a record based on its primary key or unique constraints; if none
1992 is found, creates one and returns that instead.
1994 my $cd = $schema->resultset('CD')->find_or_create({
1996 artist => 'Massive Attack',
1997 title => 'Mezzanine',
2001 Also takes an optional C<key> attribute, to search by a specific key or unique
2002 constraint. For example:
2004 my $cd = $schema->resultset('CD')->find_or_create(
2006 artist => 'Massive Attack',
2007 title => 'Mezzanine',
2009 { key => 'cd_artist_title' }
2012 B<Note>: Because find_or_create() reads from the database and then
2013 possibly inserts based on the result, this method is subject to a race
2014 condition. Another process could create a record in the table after
2015 the find has completed and before the create has started. To avoid
2016 this problem, use find_or_create() inside a transaction.
2018 B<Note>: C<find_or_create> is probably not what you want when creating
2019 a new row in a table that uses primary keys supplied by the
2020 database. Passing in a primary key column with a value of I<undef>
2021 will cause L</find> to attempt to search for a row with a value of
2024 See also L</find> and L</update_or_create>. For information on how to declare
2025 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2029 sub find_or_create {
2031 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2032 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2033 my $exists = $self->find($hash, $attrs);
2034 return defined $exists ? $exists : $self->create($hash);
2037 =head2 update_or_create
2041 =item Arguments: \%col_values, { key => $unique_constraint }?
2043 =item Return Value: $rowobject
2047 $resultset->update_or_create({ col => $val, ... });
2049 First, searches for an existing row matching one of the unique constraints
2050 (including the primary key) on the source of this resultset. If a row is
2051 found, updates it with the other given column values. Otherwise, creates a new
2054 Takes an optional C<key> attribute to search on a specific unique constraint.
2057 # In your application
2058 my $cd = $schema->resultset('CD')->update_or_create(
2060 artist => 'Massive Attack',
2061 title => 'Mezzanine',
2064 { key => 'cd_artist_title' }
2067 $cd->cd_to_producer->update_or_create({
2068 producer => $producer,
2075 If no C<key> is specified, it searches on all unique constraints defined on the
2076 source, including the primary key.
2078 If the C<key> is specified as C<primary>, it searches only on the primary key.
2080 See also L</find> and L</find_or_create>. For information on how to declare
2081 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2083 B<Note>: C<update_or_create> is probably not what you want when
2084 looking for a row in a table that uses primary keys supplied by the
2085 database, unless you actually have a key value. Passing in a primary
2086 key column with a value of I<undef> will cause L</find> to attempt to
2087 search for a row with a value of I<NULL>.
2091 sub update_or_create {
2093 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2094 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2096 my $row = $self->find($cond, $attrs);
2098 $row->update($cond);
2102 return $self->create($cond);
2109 =item Arguments: none
2111 =item Return Value: \@cache_objects?
2115 Gets the contents of the cache for the resultset, if the cache is set.
2117 The cache is populated either by using the L</prefetch> attribute to
2118 L</search> or by calling L</set_cache>.
2130 =item Arguments: \@cache_objects
2132 =item Return Value: \@cache_objects
2136 Sets the contents of the cache for the resultset. Expects an arrayref
2137 of objects of the same class as those produced by the resultset. Note that
2138 if the cache is set the resultset will return the cached objects rather
2139 than re-querying the database even if the cache attr is not set.
2141 The contents of the cache can also be populated by using the
2142 L</prefetch> attribute to L</search>.
2147 my ( $self, $data ) = @_;
2148 $self->throw_exception("set_cache requires an arrayref")
2149 if defined($data) && (ref $data ne 'ARRAY');
2150 $self->{all_cache} = $data;
2157 =item Arguments: none
2159 =item Return Value: []
2163 Clears the cache for the resultset.
2168 shift->set_cache(undef);
2171 =head2 related_resultset
2175 =item Arguments: $relationship_name
2177 =item Return Value: $resultset
2181 Returns a related resultset for the supplied relationship name.
2183 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2187 sub related_resultset {
2188 my ($self, $rel) = @_;
2190 $self->{related_resultsets} ||= {};
2191 return $self->{related_resultsets}{$rel} ||= do {
2192 my $rel_obj = $self->result_source->relationship_info($rel);
2194 $self->throw_exception(
2195 "search_related: result source '" . $self->result_source->source_name .
2196 "' has no such relationship $rel")
2199 my ($from,$seen) = $self->_resolve_from($rel);
2201 my $join_count = $seen->{$rel};
2202 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2204 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2205 my %attrs = %{$self->{attrs}||{}};
2206 delete @attrs{qw(result_class alias)};
2210 if (my $cache = $self->get_cache) {
2211 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2212 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2217 my $rel_source = $self->result_source->related_source($rel);
2221 # The reason we do this now instead of passing the alias to the
2222 # search_rs below is that if you wrap/overload resultset on the
2223 # source you need to know what alias it's -going- to have for things
2224 # to work sanely (e.g. RestrictWithObject wants to be able to add
2225 # extra query restrictions, and these may need to be $alias.)
2227 my $attrs = $rel_source->resultset_attributes;
2228 local $attrs->{alias} = $alias;
2230 $rel_source->resultset
2238 where => $self->{cond},
2243 $new->set_cache($new_cache) if $new_cache;
2248 =head2 current_source_alias
2252 =item Arguments: none
2254 =item Return Value: $source_alias
2258 Returns the current table alias for the result source this resultset is built
2259 on, that will be used in the SQL query. Usually it is C<me>.
2261 Currently the source alias that refers to the result set returned by a
2262 L</search>/L</find> family method depends on how you got to the resultset: it's
2263 C<me> by default, but eg. L</search_related> aliases it to the related result
2264 source name (and keeps C<me> referring to the original result set). The long
2265 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2266 (and make this method unnecessary).
2268 Thus it's currently necessary to use this method in predefined queries (see
2269 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2270 source alias of the current result set:
2272 # in a result set class
2274 my ($self, $user) = @_;
2276 my $me = $self->current_source_alias;
2278 return $self->search(
2279 "$me.modified" => $user->id,
2285 sub current_source_alias {
2288 return ($self->{attrs} || {})->{alias} || 'me';
2292 my ($self, $extra_join) = @_;
2293 my $source = $self->result_source;
2294 my $attrs = $self->{attrs};
2296 my $from = $attrs->{from}
2297 || [ { $attrs->{alias} => $source->from } ];
2299 my $seen = { %{$attrs->{seen_join}||{}} };
2301 my $join = ($attrs->{join}
2302 ? [ $attrs->{join}, $extra_join ]
2305 # we need to take the prefetch the attrs into account before we
2306 # ->resolve_join as otherwise they get lost - captainL
2307 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2311 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2314 return ($from,$seen);
2317 sub _resolved_attrs {
2319 return $self->{_attrs} if $self->{_attrs};
2321 my $attrs = { %{ $self->{attrs} || {} } };
2322 my $source = $self->result_source;
2323 my $alias = $attrs->{alias};
2325 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2328 # build columns (as long as select isn't set) into a set of as/select hashes
2329 unless ( $attrs->{select} ) {
2331 ( ref($_) eq 'HASH' ) ? $_
2334 /^\Q${alias}.\E(.+)$/ ? $1
2336 ) => ( /\./ ? $_ : "${alias}.$_" )
2338 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2340 # add the additional columns on
2341 foreach ( 'include_columns', '+columns' ) {
2342 push @colbits, map {
2343 ( ref($_) eq 'HASH' )
2345 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2346 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2349 # start with initial select items
2350 if ( $attrs->{select} ) {
2352 ( ref $attrs->{select} eq 'ARRAY' )
2353 ? [ @{ $attrs->{select} } ]
2354 : [ $attrs->{select} ];
2358 ref $attrs->{as} eq 'ARRAY'
2359 ? [ @{ $attrs->{as} } ]
2362 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2367 # otherwise we intialise select & as to empty
2368 $attrs->{select} = [];
2372 # now add colbits to select/as
2373 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2374 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2377 if ( $adds = delete $attrs->{'+select'} ) {
2378 $adds = [$adds] unless ref $adds eq 'ARRAY';
2380 @{ $attrs->{select} },
2381 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2384 if ( $adds = delete $attrs->{'+as'} ) {
2385 $adds = [$adds] unless ref $adds eq 'ARRAY';
2386 push( @{ $attrs->{as} }, @$adds );
2389 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2391 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2392 my $join = delete $attrs->{join} || {};
2394 if ( defined $attrs->{prefetch} ) {
2395 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2399 $attrs->{from} = # have to copy here to avoid corrupting the original
2401 @{ $attrs->{from} },
2402 $source->resolve_join(
2403 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2409 $attrs->{group_by} ||= $attrs->{select}
2410 if delete $attrs->{distinct};
2411 if ( $attrs->{order_by} ) {
2412 $attrs->{order_by} = (
2413 ref( $attrs->{order_by} ) eq 'ARRAY'
2414 ? [ @{ $attrs->{order_by} } ]
2415 : [ $attrs->{order_by} ]
2419 $attrs->{order_by} = [];
2422 my $collapse = $attrs->{collapse} || {};
2423 if ( my $prefetch = delete $attrs->{prefetch} ) {
2424 $prefetch = $self->_merge_attr( {}, $prefetch );
2426 my $seen = { %{ $attrs->{seen_join} || {} } };
2427 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2429 # bring joins back to level of current class
2431 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2432 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2433 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2435 push( @{ $attrs->{order_by} }, @pre_order );
2437 $attrs->{collapse} = $collapse;
2439 if ( $attrs->{page} ) {
2440 $attrs->{offset} ||= 0;
2441 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2444 return $self->{_attrs} = $attrs;
2448 my ($self, $attr) = @_;
2450 if (ref $attr eq 'HASH') {
2451 return $self->_rollout_hash($attr);
2452 } elsif (ref $attr eq 'ARRAY') {
2453 return $self->_rollout_array($attr);
2459 sub _rollout_array {
2460 my ($self, $attr) = @_;
2463 foreach my $element (@{$attr}) {
2464 if (ref $element eq 'HASH') {
2465 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2466 } elsif (ref $element eq 'ARRAY') {
2467 # XXX - should probably recurse here
2468 push( @rolled_array, @{$self->_rollout_array($element)} );
2470 push( @rolled_array, $element );
2473 return \@rolled_array;
2477 my ($self, $attr) = @_;
2480 foreach my $key (keys %{$attr}) {
2481 push( @rolled_array, { $key => $attr->{$key} } );
2483 return \@rolled_array;
2486 sub _calculate_score {
2487 my ($self, $a, $b) = @_;
2489 if (ref $b eq 'HASH') {
2490 my ($b_key) = keys %{$b};
2491 if (ref $a eq 'HASH') {
2492 my ($a_key) = keys %{$a};
2493 if ($a_key eq $b_key) {
2494 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2499 return ($a eq $b_key) ? 1 : 0;
2502 if (ref $a eq 'HASH') {
2503 my ($a_key) = keys %{$a};
2504 return ($b eq $a_key) ? 1 : 0;
2506 return ($b eq $a) ? 1 : 0;
2512 my ($self, $orig, $import) = @_;
2514 return $import unless defined($orig);
2515 return $orig unless defined($import);
2517 $orig = $self->_rollout_attr($orig);
2518 $import = $self->_rollout_attr($import);
2521 foreach my $import_element ( @{$import} ) {
2522 # find best candidate from $orig to merge $b_element into
2523 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2524 foreach my $orig_element ( @{$orig} ) {
2525 my $score = $self->_calculate_score( $orig_element, $import_element );
2526 if ($score > $best_candidate->{score}) {
2527 $best_candidate->{position} = $position;
2528 $best_candidate->{score} = $score;
2532 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2534 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2535 push( @{$orig}, $import_element );
2537 my $orig_best = $orig->[$best_candidate->{position}];
2538 # merge orig_best and b_element together and replace original with merged
2539 if (ref $orig_best ne 'HASH') {
2540 $orig->[$best_candidate->{position}] = $import_element;
2541 } elsif (ref $import_element eq 'HASH') {
2542 my ($key) = keys %{$orig_best};
2543 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2546 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2556 $self->_source_handle($_[0]->handle);
2558 $self->_source_handle->resolve;
2562 =head2 throw_exception
2564 See L<DBIx::Class::Schema/throw_exception> for details.
2568 sub throw_exception {
2570 if (ref $self && $self->_source_handle->schema) {
2571 $self->_source_handle->schema->throw_exception(@_)
2578 # XXX: FIXME: Attributes docs need clearing up
2582 Attributes are used to refine a ResultSet in various ways when
2583 searching for data. They can be passed to any method which takes an
2584 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2587 These are in no particular order:
2593 =item Value: ( $order_by | \@order_by | \%order_by )
2597 Which column(s) to order the results by. If a single column name, or
2598 an arrayref of names is supplied, the argument is passed through
2599 directly to SQL. The hashref syntax allows for connection-agnostic
2600 specification of ordering direction:
2602 For descending order:
2604 order_by => { -desc => [qw/col1 col2 col3/] }
2606 For explicit ascending order:
2608 order_by => { -asc => 'col' }
2610 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2611 supported, although you are strongly encouraged to use the hashref
2612 syntax as outlined above.
2618 =item Value: \@columns
2622 Shortcut to request a particular set of columns to be retrieved. Each
2623 column spec may be a string (a table column name), or a hash (in which
2624 case the key is the C<as> value, and the value is used as the C<select>
2625 expression). Adds C<me.> onto the start of any column without a C<.> in
2626 it and sets C<select> from that, then auto-populates C<as> from
2627 C<select> as normal. (You may also use the C<cols> attribute, as in
2628 earlier versions of DBIC.)
2634 =item Value: \@columns
2638 Indicates additional columns to be selected from storage. Works the same
2639 as L</columns> but adds columns to the selection. (You may also use the
2640 C<include_columns> attribute, as in earlier versions of DBIC). For
2643 $schema->resultset('CD')->search(undef, {
2644 '+columns' => ['artist.name'],
2648 would return all CDs and include a 'name' column to the information
2649 passed to object inflation. Note that the 'artist' is the name of the
2650 column (or relationship) accessor, and 'name' is the name of the column
2651 accessor in the related table.
2653 =head2 include_columns
2657 =item Value: \@columns
2661 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2667 =item Value: \@select_columns
2671 Indicates which columns should be selected from the storage. You can use
2672 column names, or in the case of RDBMS back ends, function or stored procedure
2675 $rs = $schema->resultset('Employee')->search(undef, {
2678 { count => 'employeeid' },
2683 When you use function/stored procedure names and do not supply an C<as>
2684 attribute, the column names returned are storage-dependent. E.g. MySQL would
2685 return a column named C<count(employeeid)> in the above example.
2691 Indicates additional columns to be selected from storage. Works the same as
2692 L</select> but adds columns to the selection.
2700 Indicates additional column names for those added via L</+select>. See L</as>.
2708 =item Value: \@inflation_names
2712 Indicates column names for object inflation. That is, C<as>
2713 indicates the name that the column can be accessed as via the
2714 C<get_column> method (or via the object accessor, B<if one already
2715 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2717 The C<as> attribute is used in conjunction with C<select>,
2718 usually when C<select> contains one or more function or stored
2721 $rs = $schema->resultset('Employee')->search(undef, {
2724 { count => 'employeeid' }
2726 as => ['name', 'employee_count'],
2729 my $employee = $rs->first(); # get the first Employee
2731 If the object against which the search is performed already has an accessor
2732 matching a column name specified in C<as>, the value can be retrieved using
2733 the accessor as normal:
2735 my $name = $employee->name();
2737 If on the other hand an accessor does not exist in the object, you need to
2738 use C<get_column> instead:
2740 my $employee_count = $employee->get_column('employee_count');
2742 You can create your own accessors if required - see
2743 L<DBIx::Class::Manual::Cookbook> for details.
2745 Please note: This will NOT insert an C<AS employee_count> into the SQL
2746 statement produced, it is used for internal access only. Thus
2747 attempting to use the accessor in an C<order_by> clause or similar
2748 will fail miserably.
2750 To get around this limitation, you can supply literal SQL to your
2751 C<select> attibute that contains the C<AS alias> text, eg:
2753 select => [\'myfield AS alias']
2759 =item Value: ($rel_name | \@rel_names | \%rel_names)
2763 Contains a list of relationships that should be joined for this query. For
2766 # Get CDs by Nine Inch Nails
2767 my $rs = $schema->resultset('CD')->search(
2768 { 'artist.name' => 'Nine Inch Nails' },
2769 { join => 'artist' }
2772 Can also contain a hash reference to refer to the other relation's relations.
2775 package MyApp::Schema::Track;
2776 use base qw/DBIx::Class/;
2777 __PACKAGE__->table('track');
2778 __PACKAGE__->add_columns(qw/trackid cd position title/);
2779 __PACKAGE__->set_primary_key('trackid');
2780 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2783 # In your application
2784 my $rs = $schema->resultset('Artist')->search(
2785 { 'track.title' => 'Teardrop' },
2787 join => { cd => 'track' },
2788 order_by => 'artist.name',
2792 You need to use the relationship (not the table) name in conditions,
2793 because they are aliased as such. The current table is aliased as "me", so
2794 you need to use me.column_name in order to avoid ambiguity. For example:
2796 # Get CDs from 1984 with a 'Foo' track
2797 my $rs = $schema->resultset('CD')->search(
2800 'tracks.name' => 'Foo'
2802 { join => 'tracks' }
2805 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2806 similarly for a third time). For e.g.
2808 my $rs = $schema->resultset('Artist')->search({
2809 'cds.title' => 'Down to Earth',
2810 'cds_2.title' => 'Popular',
2812 join => [ qw/cds cds/ ],
2815 will return a set of all artists that have both a cd with title 'Down
2816 to Earth' and a cd with title 'Popular'.
2818 If you want to fetch related objects from other tables as well, see C<prefetch>
2821 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2827 =item Value: ($rel_name | \@rel_names | \%rel_names)
2831 Contains one or more relationships that should be fetched along with
2832 the main query (when they are accessed afterwards the data will
2833 already be available, without extra queries to the database). This is
2834 useful for when you know you will need the related objects, because it
2835 saves at least one query:
2837 my $rs = $schema->resultset('Tag')->search(
2846 The initial search results in SQL like the following:
2848 SELECT tag.*, cd.*, artist.* FROM tag
2849 JOIN cd ON tag.cd = cd.cdid
2850 JOIN artist ON cd.artist = artist.artistid
2852 L<DBIx::Class> has no need to go back to the database when we access the
2853 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2856 Simple prefetches will be joined automatically, so there is no need
2857 for a C<join> attribute in the above search.
2859 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2860 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2861 with an accessor type of 'single' or 'filter'). A more complex example that
2862 prefetches an artists cds, the tracks on those cds, and the tags associted
2863 with that artist is given below (assuming many-to-many from artists to tags):
2865 my $rs = $schema->resultset('Artist')->search(
2869 { cds => 'tracks' },
2870 { artist_tags => 'tags' }
2876 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2877 attributes will be ignored.
2887 Makes the resultset paged and specifies the page to retrieve. Effectively
2888 identical to creating a non-pages resultset and then calling ->page($page)
2891 If L<rows> attribute is not specified it defualts to 10 rows per page.
2893 When you have a paged resultset, L</count> will only return the number
2894 of rows in the page. To get the total, use the L</pager> and call
2895 C<total_entries> on it.
2905 Specifes the maximum number of rows for direct retrieval or the number of
2906 rows per page if the page attribute or method is used.
2912 =item Value: $offset
2916 Specifies the (zero-based) row number for the first row to be returned, or the
2917 of the first row of the first page if paging is used.
2923 =item Value: \@columns
2927 A arrayref of columns to group by. Can include columns of joined tables.
2929 group_by => [qw/ column1 column2 ... /]
2935 =item Value: $condition
2939 HAVING is a select statement attribute that is applied between GROUP BY and
2940 ORDER BY. It is applied to the after the grouping calculations have been
2943 having => { 'count(employee)' => { '>=', 100 } }
2949 =item Value: (0 | 1)
2953 Set to 1 to group by all columns.
2959 Adds to the WHERE clause.
2961 # only return rows WHERE deleted IS NULL for all searches
2962 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2964 Can be overridden by passing C<{ where => undef }> as an attribute
2971 Set to 1 to cache search results. This prevents extra SQL queries if you
2972 revisit rows in your ResultSet:
2974 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
2976 while( my $artist = $resultset->next ) {
2980 $rs->first; # without cache, this would issue a query
2982 By default, searches are not cached.
2984 For more examples of using these attributes, see
2985 L<DBIx::Class::Manual::Cookbook>.
2991 =item Value: \@from_clause
2995 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
2996 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
2999 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3001 C<join> will usually do what you need and it is strongly recommended that you
3002 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3003 And we really do mean "cannot", not just tried and failed. Attempting to use
3004 this because you're having problems with C<join> is like trying to use x86
3005 ASM because you've got a syntax error in your C. Trust us on this.
3007 Now, if you're still really, really sure you need to use this (and if you're
3008 not 100% sure, ask the mailing list first), here's an explanation of how this
3011 The syntax is as follows -
3014 { <alias1> => <table1> },
3016 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3017 [], # nested JOIN (optional)
3018 { <table1.column1> => <table2.column2>, ... (more conditions) },
3020 # More of the above [ ] may follow for additional joins
3027 ON <table1.column1> = <table2.column2>
3028 <more joins may follow>
3030 An easy way to follow the examples below is to remember the following:
3032 Anything inside "[]" is a JOIN
3033 Anything inside "{}" is a condition for the enclosing JOIN
3035 The following examples utilize a "person" table in a family tree application.
3036 In order to express parent->child relationships, this table is self-joined:
3038 # Person->belongs_to('father' => 'Person');
3039 # Person->belongs_to('mother' => 'Person');
3041 C<from> can be used to nest joins. Here we return all children with a father,
3042 then search against all mothers of those children:
3044 $rs = $schema->resultset('Person')->search(
3047 alias => 'mother', # alias columns in accordance with "from"
3049 { mother => 'person' },
3052 { child => 'person' },
3054 { father => 'person' },
3055 { 'father.person_id' => 'child.father_id' }
3058 { 'mother.person_id' => 'child.mother_id' }
3065 # SELECT mother.* FROM person mother
3068 # JOIN person father
3069 # ON ( father.person_id = child.father_id )
3071 # ON ( mother.person_id = child.mother_id )
3073 The type of any join can be controlled manually. To search against only people
3074 with a father in the person table, we could explicitly use C<INNER JOIN>:
3076 $rs = $schema->resultset('Person')->search(
3079 alias => 'child', # alias columns in accordance with "from"
3081 { child => 'person' },
3083 { father => 'person', -join_type => 'inner' },
3084 { 'father.id' => 'child.father_id' }
3091 # SELECT child.* FROM person child
3092 # INNER JOIN person father ON child.father_id = father.id
3094 If you need to express really complex joins or you need a subselect, you
3095 can supply literal SQL to C<from> via a scalar reference. In this case
3096 the contents of the scalar will replace the table name asscoiated with the
3099 WARNING: This technique might very well not work as expected on chained
3100 searches - you have been warned.
3102 # Assuming the Event resultsource is defined as:
3104 MySchema::Event->add_columns (
3107 is_auto_increment => 1,
3116 MySchema::Event->set_primary_key ('sequence');
3118 # This will get back the latest event for every location. The column
3119 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3120 # combo to limit the resultset
3122 $rs = $schema->resultset('Event');
3123 $table = $rs->result_source->name;
3124 $latest = $rs->search (
3127 (SELECT e1.* FROM $table e1
3129 ON e1.location = e2.location
3130 AND e1.sequence < e2.sequence
3131 WHERE e2.sequence is NULL
3136 # Equivalent SQL (with the DBIC chunks added):
3138 SELECT me.sequence, me.location, me.type FROM
3139 (SELECT e1.* FROM events e1
3141 ON e1.location = e2.location
3142 AND e1.sequence < e2.sequence
3143 WHERE e2.sequence is NULL
3150 =item Value: ( 'update' | 'shared' )
3154 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT