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 $collapsed = $self->_collapse_query($subquery, $collapsed);
802 elsif (ref $query eq 'HASH') {
803 if (keys %$query and (keys %$query)[0] eq '-and') {
804 foreach my $subquery (@{$query->{-and}}) {
805 $collapsed = $self->_collapse_query($subquery, $collapsed);
809 foreach my $col (keys %$query) {
810 my $value = $query->{$col};
811 $collapsed->{$col}{$value}++;
823 =item Arguments: $cond?
825 =item Return Value: $resultsetcolumn
829 my $max_length = $rs->get_column('length')->max;
831 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
836 my ($self, $column) = @_;
837 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
845 =item Arguments: $cond, \%attrs?
847 =item Return Value: $resultset (scalar context), @row_objs (list context)
851 # WHERE title LIKE '%blue%'
852 $cd_rs = $rs->search_like({ title => '%blue%'});
854 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
855 that this is simply a convenience method retained for ex Class::DBI users.
856 You most likely want to use L</search> with specific operators.
858 For more information, see L<DBIx::Class::Manual::Cookbook>.
860 This method is deprecated and will be removed in 0.09. Use L</search()>
861 instead. An example conversion is:
863 ->search_like({ foo => 'bar' });
867 ->search({ foo => { like => 'bar' } });
874 'search_like() is deprecated and will be removed in 0.09.',
875 'Instead use ->search({ x => { -like => "y%" } })',
876 '(note the outer pair of {}s - they are important!)'
878 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
879 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
880 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
881 return $class->search($query, { %$attrs });
888 =item Arguments: $first, $last
890 =item Return Value: $resultset (scalar context), @row_objs (list context)
894 Returns a resultset or object list representing a subset of elements from the
895 resultset slice is called on. Indexes are from 0, i.e., to get the first
898 my ($one, $two, $three) = $rs->slice(0, 2);
903 my ($self, $min, $max) = @_;
904 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
905 $attrs->{offset} = $self->{attrs}{offset} || 0;
906 $attrs->{offset} += $min;
907 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
908 return $self->search(undef(), $attrs);
909 #my $slice = (ref $self)->new($self->result_source, $attrs);
910 #return (wantarray ? $slice->all : $slice);
917 =item Arguments: none
919 =item Return Value: $result?
923 Returns the next element in the resultset (C<undef> is there is none).
925 Can be used to efficiently iterate over records in the resultset:
927 my $rs = $schema->resultset('CD')->search;
928 while (my $cd = $rs->next) {
932 Note that you need to store the resultset object, and call C<next> on it.
933 Calling C<< resultset('Table')->next >> repeatedly will always return the
934 first record from the resultset.
940 if (my $cache = $self->get_cache) {
941 $self->{all_cache_position} ||= 0;
942 return $cache->[$self->{all_cache_position}++];
944 if ($self->{attrs}{cache}) {
945 $self->{all_cache_position} = 1;
946 return ($self->all)[0];
948 if ($self->{stashed_objects}) {
949 my $obj = shift(@{$self->{stashed_objects}});
950 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
954 exists $self->{stashed_row}
955 ? @{delete $self->{stashed_row}}
956 : $self->cursor->next
958 return undef unless (@row);
959 my ($row, @more) = $self->_construct_object(@row);
960 $self->{stashed_objects} = \@more if @more;
964 sub _construct_object {
965 my ($self, @row) = @_;
966 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
967 my @new = $self->result_class->inflate_result($self->result_source, @$info);
968 @new = $self->{_attrs}{record_filter}->(@new)
969 if exists $self->{_attrs}{record_filter};
973 sub _collapse_result {
974 my ($self, $as_proto, $row) = @_;
978 # 'foo' => [ undef, 'foo' ]
979 # 'foo.bar' => [ 'foo', 'bar' ]
980 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
982 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
984 my %collapse = %{$self->{_attrs}{collapse}||{}};
988 # if we're doing collapsing (has_many prefetch) we need to grab records
989 # until the PK changes, so fill @pri_index. if not, we leave it empty so
990 # we know we don't have to bother.
992 # the reason for not using the collapse stuff directly is because if you
993 # had for e.g. two artists in a row with no cds, the collapse info for
994 # both would be NULL (undef) so you'd lose the second artist
996 # store just the index so we can check the array positions from the row
997 # without having to contruct the full hash
999 if (keys %collapse) {
1000 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1001 foreach my $i (0 .. $#construct_as) {
1002 next if defined($construct_as[$i][0]); # only self table
1003 if (delete $pri{$construct_as[$i][1]}) {
1004 push(@pri_index, $i);
1006 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1010 # no need to do an if, it'll be empty if @pri_index is empty anyway
1012 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1016 do { # no need to check anything at the front, we always want the first row
1020 foreach my $this_as (@construct_as) {
1021 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1024 push(@const_rows, \%const);
1026 } until ( # no pri_index => no collapse => drop straight out
1029 do { # get another row, stash it, drop out if different PK
1031 @copy = $self->cursor->next;
1032 $self->{stashed_row} = \@copy;
1034 # last thing in do block, counts as true if anything doesn't match
1036 # check xor defined first for NULL vs. NOT NULL then if one is
1037 # defined the other must be so check string equality
1040 (defined $pri_vals{$_} ^ defined $copy[$_])
1041 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1046 my $alias = $self->{attrs}{alias};
1053 foreach my $const (@const_rows) {
1054 scalar @const_keys or do {
1055 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1057 foreach my $key (@const_keys) {
1060 my @parts = split(/\./, $key);
1062 my $data = $const->{$key};
1063 foreach my $p (@parts) {
1064 $target = $target->[1]->{$p} ||= [];
1066 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1067 # collapsing at this point and on final part
1068 my $pos = $collapse_pos{$cur};
1069 CK: foreach my $ck (@ckey) {
1070 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1071 $collapse_pos{$cur} = $data;
1072 delete @collapse_pos{ # clear all positioning for sub-entries
1073 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1080 if (exists $collapse{$cur}) {
1081 $target = $target->[-1];
1084 $target->[0] = $data;
1086 $info->[0] = $const->{$key};
1094 =head2 result_source
1098 =item Arguments: $result_source?
1100 =item Return Value: $result_source
1104 An accessor for the primary ResultSource object from which this ResultSet
1111 =item Arguments: $result_class?
1113 =item Return Value: $result_class
1117 An accessor for the class to use when creating row objects. Defaults to
1118 C<< result_source->result_class >> - which in most cases is the name of the
1119 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1121 Note that changing the result_class will also remove any components
1122 that were originally loaded in the source class via
1123 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1124 in the original source class will not run.
1129 my ($self, $result_class) = @_;
1130 if ($result_class) {
1131 $self->ensure_class_loaded($result_class);
1132 $self->_result_class($result_class);
1134 $self->_result_class;
1141 =item Arguments: $cond, \%attrs??
1143 =item Return Value: $count
1147 Performs an SQL C<COUNT> with the same query as the resultset was built
1148 with to find the number of elements. If passed arguments, does a search
1149 on the resultset and counts the results of that.
1151 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1152 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1153 not support C<DISTINCT> with multiple columns. If you are using such a
1154 database, you should only use columns from the main table in your C<group_by>
1161 return $self->search(@_)->count if @_ and defined $_[0];
1162 return scalar @{ $self->get_cache } if $self->get_cache;
1163 my $count = $self->_count;
1164 return 0 unless $count;
1166 # need to take offset from resolved attrs
1168 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1169 $count = $self->{attrs}{rows} if
1170 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1171 $count = 0 if ($count < 0);
1175 sub _count { # Separated out so pager can get the full count
1177 my $select = { count => '*' };
1179 my $attrs = { %{$self->_resolved_attrs} };
1180 if (my $group_by = delete $attrs->{group_by}) {
1181 delete $attrs->{having};
1182 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1183 # todo: try CONCAT for multi-column pk
1184 my @pk = $self->result_source->primary_columns;
1186 my $alias = $attrs->{alias};
1187 foreach my $column (@distinct) {
1188 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1189 @distinct = ($column);
1195 $select = { count => { distinct => \@distinct } };
1198 $attrs->{select} = $select;
1199 $attrs->{as} = [qw/count/];
1201 # offset, order by and page are not needed to count. record_filter is cdbi
1202 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1204 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1205 my ($count) = $tmp_rs->cursor->next;
1213 =head2 count_literal
1217 =item Arguments: $sql_fragment, @bind_values
1219 =item Return Value: $count
1223 Counts the results in a literal query. Equivalent to calling L</search_literal>
1224 with the passed arguments, then L</count>.
1228 sub count_literal { shift->search_literal(@_)->count; }
1234 =item Arguments: none
1236 =item Return Value: @objects
1240 Returns all elements in the resultset. Called implicitly if the resultset
1241 is returned in list context.
1248 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1251 return @{ $self->get_cache } if $self->get_cache;
1255 # TODO: don't call resolve here
1256 if (keys %{$self->_resolved_attrs->{collapse}}) {
1257 # if ($self->{attrs}{prefetch}) {
1258 # Using $self->cursor->all is really just an optimisation.
1259 # If we're collapsing has_many prefetches it probably makes
1260 # very little difference, and this is cleaner than hacking
1261 # _construct_object to survive the approach
1262 my @row = $self->cursor->next;
1264 push(@obj, $self->_construct_object(@row));
1265 @row = (exists $self->{stashed_row}
1266 ? @{delete $self->{stashed_row}}
1267 : $self->cursor->next);
1270 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1273 $self->set_cache(\@obj) if $self->{attrs}{cache};
1281 =item Arguments: none
1283 =item Return Value: $self
1287 Resets the resultset's cursor, so you can iterate through the elements again.
1293 delete $self->{_attrs} if exists $self->{_attrs};
1294 $self->{all_cache_position} = 0;
1295 $self->cursor->reset;
1303 =item Arguments: none
1305 =item Return Value: $object?
1309 Resets the resultset and returns an object for the first result (if the
1310 resultset returns anything).
1315 return $_[0]->reset->next;
1318 # _cond_for_update_delete
1320 # update/delete require the condition to be modified to handle
1321 # the differing SQL syntax available. This transforms the $self->{cond}
1322 # appropriately, returning the new condition.
1324 sub _cond_for_update_delete {
1325 my ($self, $full_cond) = @_;
1328 $full_cond ||= $self->{cond};
1329 # No-op. No condition, we're updating/deleting everything
1330 return $cond unless ref $full_cond;
1332 foreach my $pk ($self->result_source->primary_columns) {
1333 $cond->{$pk} = { -in => $self->get_column($pk)->as_query };
1344 =item Arguments: \%values
1346 =item Return Value: $storage_rv
1350 Sets the specified columns in the resultset to the supplied values in a
1351 single query. Return value will be true if the update succeeded or false
1352 if no records were updated; exact type of success value is storage-dependent.
1357 my ($self, $values) = @_;
1358 $self->throw_exception("Values for update must be a hash")
1359 unless ref $values eq 'HASH';
1361 my $cond = $self->_cond_for_update_delete;
1363 return $self->result_source->storage->update(
1364 $self->result_source, $values, $cond
1372 =item Arguments: \%values
1374 =item Return Value: 1
1378 Fetches all objects and updates them one at a time. Note that C<update_all>
1379 will run DBIC cascade triggers, while L</update> will not.
1384 my ($self, $values) = @_;
1385 $self->throw_exception("Values for update must be a hash")
1386 unless ref $values eq 'HASH';
1387 foreach my $obj ($self->all) {
1388 $obj->set_columns($values)->update;
1397 =item Arguments: none
1399 =item Return Value: 1
1403 Deletes the contents of the resultset from its result source. Note that this
1404 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1405 to run. See also L<DBIx::Class::Row/delete>.
1407 delete may not generate correct SQL for a query with joins or a resultset
1408 chained from a related resultset. In this case it will generate a warning:-
1410 In these cases you may find that delete_all is more appropriate, or you
1411 need to respecify your query in a way that can be expressed without a join.
1417 $self->throw_exception("Delete should not be passed any arguments")
1420 my $cond = $self->_cond_for_update_delete;
1422 $self->result_source->storage->delete($self->result_source, $cond);
1430 =item Arguments: none
1432 =item Return Value: 1
1436 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1437 will run DBIC cascade triggers, while L</delete> will not.
1443 $_->delete for $self->all;
1451 =item Arguments: \@data;
1455 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1456 For the arrayref of hashrefs style each hashref should be a structure suitable
1457 forsubmitting to a $resultset->create(...) method.
1459 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1460 to insert the data, as this is a faster method.
1462 Otherwise, each set of data is inserted into the database using
1463 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1464 objects is returned.
1466 Example: Assuming an Artist Class that has many CDs Classes relating:
1468 my $Artist_rs = $schema->resultset("Artist");
1470 ## Void Context Example
1471 $Artist_rs->populate([
1472 { artistid => 4, name => 'Manufactured Crap', cds => [
1473 { title => 'My First CD', year => 2006 },
1474 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1477 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1478 { title => 'My parents sold me to a record company' ,year => 2005 },
1479 { title => 'Why Am I So Ugly?', year => 2006 },
1480 { title => 'I Got Surgery and am now Popular', year => 2007 }
1485 ## Array Context Example
1486 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1487 { name => "Artist One"},
1488 { name => "Artist Two"},
1489 { name => "Artist Three", cds=> [
1490 { title => "First CD", year => 2007},
1491 { title => "Second CD", year => 2008},
1495 print $ArtistOne->name; ## response is 'Artist One'
1496 print $ArtistThree->cds->count ## reponse is '2'
1498 For the arrayref of arrayrefs style, the first element should be a list of the
1499 fieldsnames to which the remaining elements are rows being inserted. For
1502 $Arstist_rs->populate([
1503 [qw/artistid name/],
1504 [100, 'A Formally Unknown Singer'],
1505 [101, 'A singer that jumped the shark two albums ago'],
1506 [102, 'An actually cool singer.'],
1509 Please note an important effect on your data when choosing between void and
1510 wantarray context. Since void context goes straight to C<insert_bulk> in
1511 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1512 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1513 create primary keys for you, you will find that your PKs are empty. In this
1514 case you will have to use the wantarray context in order to create those
1520 my $self = shift @_;
1521 my $data = ref $_[0][0] eq 'HASH'
1522 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1523 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1525 if(defined wantarray) {
1527 foreach my $item (@$data) {
1528 push(@created, $self->create($item));
1532 my ($first, @rest) = @$data;
1534 my @names = grep {!ref $first->{$_}} keys %$first;
1535 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1536 my @pks = $self->result_source->primary_columns;
1538 ## do the belongs_to relationships
1539 foreach my $index (0..$#$data) {
1540 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1541 my @ret = $self->populate($data);
1545 foreach my $rel (@rels) {
1546 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1547 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1548 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1549 my $related = $result->result_source->resolve_condition(
1550 $result->result_source->relationship_info($reverse)->{cond},
1555 delete $data->[$index]->{$rel};
1556 $data->[$index] = {%{$data->[$index]}, %$related};
1558 push @names, keys %$related if $index == 0;
1562 ## do bulk insert on current row
1563 my @values = map { [ @$_{@names} ] } @$data;
1565 $self->result_source->storage->insert_bulk(
1566 $self->result_source,
1571 ## do the has_many relationships
1572 foreach my $item (@$data) {
1574 foreach my $rel (@rels) {
1575 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1577 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1578 || $self->throw_exception('Cannot find the relating object.');
1580 my $child = $parent->$rel;
1582 my $related = $child->result_source->resolve_condition(
1583 $parent->result_source->relationship_info($rel)->{cond},
1588 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1589 my @populate = map { {%$_, %$related} } @rows_to_add;
1591 $child->populate( \@populate );
1597 =head2 _normalize_populate_args ($args)
1599 Private method used by L</populate> to normalize its incoming arguments. Factored
1600 out in case you want to subclass and accept new argument structures to the
1601 L</populate> method.
1605 sub _normalize_populate_args {
1606 my ($self, $data) = @_;
1607 my @names = @{shift(@$data)};
1608 my @results_to_create;
1609 foreach my $datum (@$data) {
1610 my %result_to_create;
1611 foreach my $index (0..$#names) {
1612 $result_to_create{$names[$index]} = $$datum[$index];
1614 push @results_to_create, \%result_to_create;
1616 return \@results_to_create;
1623 =item Arguments: none
1625 =item Return Value: $pager
1629 Return Value a L<Data::Page> object for the current resultset. Only makes
1630 sense for queries with a C<page> attribute.
1632 To get the full count of entries for a paged resultset, call
1633 C<total_entries> on the L<Data::Page> object.
1639 my $attrs = $self->{attrs};
1640 $self->throw_exception("Can't create pager for non-paged rs")
1641 unless $self->{attrs}{page};
1642 $attrs->{rows} ||= 10;
1643 return $self->{pager} ||= Data::Page->new(
1644 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1651 =item Arguments: $page_number
1653 =item Return Value: $rs
1657 Returns a resultset for the $page_number page of the resultset on which page
1658 is called, where each page contains a number of rows equal to the 'rows'
1659 attribute set on the resultset (10 by default).
1664 my ($self, $page) = @_;
1665 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1672 =item Arguments: \%vals
1674 =item Return Value: $rowobject
1678 Creates a new row object in the resultset's result class and returns
1679 it. The row is not inserted into the database at this point, call
1680 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1681 will tell you whether the row object has been inserted or not.
1683 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1688 my ($self, $values) = @_;
1689 $self->throw_exception( "new_result needs a hash" )
1690 unless (ref $values eq 'HASH');
1693 my $alias = $self->{attrs}{alias};
1696 defined $self->{cond}
1697 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1699 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1700 $new{-from_resultset} = [ keys %new ] if keys %new;
1702 $self->throw_exception(
1703 "Can't abstract implicit construct, condition not a hash"
1704 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1706 my $collapsed_cond = (
1708 ? $self->_collapse_cond($self->{cond})
1712 # precendence must be given to passed values over values inherited from
1713 # the cond, so the order here is important.
1714 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1715 while( my($col,$value) = each %implied ){
1716 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1717 $new{$col} = $value->{'='};
1720 $new{$col} = $value if $self->_is_deterministic_value($value);
1726 %{ $self->_remove_alias($values, $alias) },
1727 -source_handle => $self->_source_handle,
1728 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1731 return $self->result_class->new(\%new);
1734 # _is_deterministic_value
1736 # Make an effor to strip non-deterministic values from the condition,
1737 # to make sure new_result chokes less
1739 sub _is_deterministic_value {
1742 my $ref_type = ref $value;
1743 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1744 return 1 if Scalar::Util::blessed($value);
1750 # Recursively collapse the condition.
1752 sub _collapse_cond {
1753 my ($self, $cond, $collapsed) = @_;
1757 if (ref $cond eq 'ARRAY') {
1758 foreach my $subcond (@$cond) {
1759 next unless ref $subcond; # -or
1760 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1763 elsif (ref $cond eq 'HASH') {
1764 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1765 foreach my $subcond (@{$cond->{-and}}) {
1766 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1770 foreach my $col (keys %$cond) {
1771 my $value = $cond->{$col};
1772 $collapsed->{$col} = $value;
1782 # Remove the specified alias from the specified query hash. A copy is made so
1783 # the original query is not modified.
1786 my ($self, $query, $alias) = @_;
1788 my %orig = %{ $query || {} };
1791 foreach my $key (keys %orig) {
1793 $unaliased{$key} = $orig{$key};
1796 $unaliased{$1} = $orig{$key}
1797 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1803 =head2 as_query (EXPERIMENTAL)
1807 =item Arguments: none
1809 =item Return Value: \[ $sql, @bind ]
1813 Returns the SQL query and bind vars associated with the invocant.
1815 This is generally used as the RHS for a subquery.
1817 B<NOTE>: This feature is still experimental.
1821 sub as_query { return shift->cursor->as_query(@_) }
1827 =item Arguments: \%vals, \%attrs?
1829 =item Return Value: $rowobject
1833 my $artist = $schema->resultset('Artist')->find_or_new(
1834 { artist => 'fred' }, { key => 'artists' });
1836 $cd->cd_to_producer->find_or_new({ producer => $producer },
1837 { key => 'primary });
1839 Find an existing record from this resultset, based on its primary
1840 key, or a unique constraint. If none exists, instantiate a new result
1841 object and return it. The object will not be saved into your storage
1842 until you call L<DBIx::Class::Row/insert> on it.
1844 You most likely want this method when looking for existing rows using
1845 a unique constraint that is not the primary key, or looking for
1848 If you want objects to be saved immediately, use L</find_or_create> instead.
1850 B<Note>: C<find_or_new> is probably not what you want when creating a
1851 new row in a table that uses primary keys supplied by the
1852 database. Passing in a primary key column with a value of I<undef>
1853 will cause L</find> to attempt to search for a row with a value of
1860 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1861 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1862 my $exists = $self->find($hash, $attrs);
1863 return defined $exists ? $exists : $self->new_result($hash);
1870 =item Arguments: \%vals
1872 =item Return Value: a L<DBIx::Class::Row> $object
1876 Attempt to create a single new row or a row with multiple related rows
1877 in the table represented by the resultset (and related tables). This
1878 will not check for duplicate rows before inserting, use
1879 L</find_or_create> to do that.
1881 To create one row for this resultset, pass a hashref of key/value
1882 pairs representing the columns of the table and the values you wish to
1883 store. If the appropriate relationships are set up, foreign key fields
1884 can also be passed an object representing the foreign row, and the
1885 value will be set to its primary key.
1887 To create related objects, pass a hashref for the value if the related
1888 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1889 and use the name of the relationship as the key. (NOT the name of the field,
1890 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1891 of hashrefs containing the data for each of the rows to create in the foreign
1892 tables, again using the relationship name as the key.
1894 Instead of hashrefs of plain related data (key/value pairs), you may
1895 also pass new or inserted objects. New objects (not inserted yet, see
1896 L</new>), will be inserted into their appropriate tables.
1898 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1900 Example of creating a new row.
1902 $person_rs->create({
1903 name=>"Some Person",
1904 email=>"somebody@someplace.com"
1907 Example of creating a new row and also creating rows in a related C<has_many>
1908 or C<has_one> resultset. Note Arrayref.
1911 { artistid => 4, name => 'Manufactured Crap', cds => [
1912 { title => 'My First CD', year => 2006 },
1913 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1918 Example of creating a new row and also creating a row in a related
1919 C<belongs_to>resultset. Note Hashref.
1922 title=>"Music for Silly Walks",
1925 name=>"Silly Musician",
1932 my ($self, $attrs) = @_;
1933 $self->throw_exception( "create needs a hashref" )
1934 unless ref $attrs eq 'HASH';
1935 return $self->new_result($attrs)->insert;
1938 =head2 find_or_create
1942 =item Arguments: \%vals, \%attrs?
1944 =item Return Value: $rowobject
1948 $cd->cd_to_producer->find_or_create({ producer => $producer },
1949 { key => 'primary });
1951 Tries to find a record based on its primary key or unique constraints; if none
1952 is found, creates one and returns that instead.
1954 my $cd = $schema->resultset('CD')->find_or_create({
1956 artist => 'Massive Attack',
1957 title => 'Mezzanine',
1961 Also takes an optional C<key> attribute, to search by a specific key or unique
1962 constraint. For example:
1964 my $cd = $schema->resultset('CD')->find_or_create(
1966 artist => 'Massive Attack',
1967 title => 'Mezzanine',
1969 { key => 'cd_artist_title' }
1972 B<Note>: Because find_or_create() reads from the database and then
1973 possibly inserts based on the result, this method is subject to a race
1974 condition. Another process could create a record in the table after
1975 the find has completed and before the create has started. To avoid
1976 this problem, use find_or_create() inside a transaction.
1978 B<Note>: C<find_or_create> is probably not what you want when creating
1979 a new row in a table that uses primary keys supplied by the
1980 database. Passing in a primary key column with a value of I<undef>
1981 will cause L</find> to attempt to search for a row with a value of
1984 See also L</find> and L</update_or_create>. For information on how to declare
1985 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
1989 sub find_or_create {
1991 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1992 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1993 my $exists = $self->find($hash, $attrs);
1994 return defined $exists ? $exists : $self->create($hash);
1997 =head2 update_or_create
2001 =item Arguments: \%col_values, { key => $unique_constraint }?
2003 =item Return Value: $rowobject
2007 $resultset->update_or_create({ col => $val, ... });
2009 First, searches for an existing row matching one of the unique constraints
2010 (including the primary key) on the source of this resultset. If a row is
2011 found, updates it with the other given column values. Otherwise, creates a new
2014 Takes an optional C<key> attribute to search on a specific unique constraint.
2017 # In your application
2018 my $cd = $schema->resultset('CD')->update_or_create(
2020 artist => 'Massive Attack',
2021 title => 'Mezzanine',
2024 { key => 'cd_artist_title' }
2027 $cd->cd_to_producer->update_or_create({
2028 producer => $producer,
2035 If no C<key> is specified, it searches on all unique constraints defined on the
2036 source, including the primary key.
2038 If the C<key> is specified as C<primary>, it searches only on the primary key.
2040 See also L</find> and L</find_or_create>. For information on how to declare
2041 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2043 B<Note>: C<update_or_create> is probably not what you want when
2044 looking for a row in a table that uses primary keys supplied by the
2045 database, unless you actually have a key value. Passing in a primary
2046 key column with a value of I<undef> will cause L</find> to attempt to
2047 search for a row with a value of I<NULL>.
2051 sub update_or_create {
2053 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2054 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2056 my $row = $self->find($cond, $attrs);
2058 $row->update($cond);
2062 return $self->create($cond);
2065 =head2 update_or_new
2069 =item Arguments: \%col_values, { key => $unique_constraint }?
2071 =item Return Value: $rowobject
2075 $resultset->update_or_new({ col => $val, ... });
2077 First, searches for an existing row matching one of the unique constraints
2078 (including the primary key) on the source of this resultset. If a row is
2079 found, updates it with the other given column values. Otherwise, instantiate
2080 a new result object and return it. The object will not be saved into your storage
2081 until you call L<DBIx::Class::Row/insert> on it.
2083 Takes an optional C<key> attribute to search on a specific unique constraint.
2086 # In your application
2087 my $cd = $schema->resultset('CD')->update_or_new(
2089 artist => 'Massive Attack',
2090 title => 'Mezzanine',
2093 { key => 'cd_artist_title' }
2096 if ($cd->in_storage) {
2097 # the cd was updated
2100 # the cd is not yet in the database, let's insert it
2104 See also L</find>, L</find_or_create> and L<find_or_new>.
2110 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2111 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2113 my $row = $self->find( $cond, $attrs );
2114 if ( defined $row ) {
2115 $row->update($cond);
2119 return $self->new_result($cond);
2126 =item Arguments: none
2128 =item Return Value: \@cache_objects?
2132 Gets the contents of the cache for the resultset, if the cache is set.
2134 The cache is populated either by using the L</prefetch> attribute to
2135 L</search> or by calling L</set_cache>.
2147 =item Arguments: \@cache_objects
2149 =item Return Value: \@cache_objects
2153 Sets the contents of the cache for the resultset. Expects an arrayref
2154 of objects of the same class as those produced by the resultset. Note that
2155 if the cache is set the resultset will return the cached objects rather
2156 than re-querying the database even if the cache attr is not set.
2158 The contents of the cache can also be populated by using the
2159 L</prefetch> attribute to L</search>.
2164 my ( $self, $data ) = @_;
2165 $self->throw_exception("set_cache requires an arrayref")
2166 if defined($data) && (ref $data ne 'ARRAY');
2167 $self->{all_cache} = $data;
2174 =item Arguments: none
2176 =item Return Value: []
2180 Clears the cache for the resultset.
2185 shift->set_cache(undef);
2188 =head2 related_resultset
2192 =item Arguments: $relationship_name
2194 =item Return Value: $resultset
2198 Returns a related resultset for the supplied relationship name.
2200 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2204 sub related_resultset {
2205 my ($self, $rel) = @_;
2207 $self->{related_resultsets} ||= {};
2208 return $self->{related_resultsets}{$rel} ||= do {
2209 my $rel_obj = $self->result_source->relationship_info($rel);
2211 $self->throw_exception(
2212 "search_related: result source '" . $self->result_source->source_name .
2213 "' has no such relationship $rel")
2216 my ($from,$seen) = $self->_resolve_from($rel);
2218 my $join_count = $seen->{$rel};
2219 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2221 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2222 my %attrs = %{$self->{attrs}||{}};
2223 delete @attrs{qw(result_class alias)};
2227 if (my $cache = $self->get_cache) {
2228 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2229 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2234 my $rel_source = $self->result_source->related_source($rel);
2238 # The reason we do this now instead of passing the alias to the
2239 # search_rs below is that if you wrap/overload resultset on the
2240 # source you need to know what alias it's -going- to have for things
2241 # to work sanely (e.g. RestrictWithObject wants to be able to add
2242 # extra query restrictions, and these may need to be $alias.)
2244 my $attrs = $rel_source->resultset_attributes;
2245 local $attrs->{alias} = $alias;
2247 $rel_source->resultset
2255 where => $self->{cond},
2260 $new->set_cache($new_cache) if $new_cache;
2265 =head2 current_source_alias
2269 =item Arguments: none
2271 =item Return Value: $source_alias
2275 Returns the current table alias for the result source this resultset is built
2276 on, that will be used in the SQL query. Usually it is C<me>.
2278 Currently the source alias that refers to the result set returned by a
2279 L</search>/L</find> family method depends on how you got to the resultset: it's
2280 C<me> by default, but eg. L</search_related> aliases it to the related result
2281 source name (and keeps C<me> referring to the original result set). The long
2282 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2283 (and make this method unnecessary).
2285 Thus it's currently necessary to use this method in predefined queries (see
2286 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2287 source alias of the current result set:
2289 # in a result set class
2291 my ($self, $user) = @_;
2293 my $me = $self->current_source_alias;
2295 return $self->search(
2296 "$me.modified" => $user->id,
2302 sub current_source_alias {
2305 return ($self->{attrs} || {})->{alias} || 'me';
2309 my ($self, $extra_join) = @_;
2310 my $source = $self->result_source;
2311 my $attrs = $self->{attrs};
2313 my $from = $attrs->{from}
2314 || [ { $attrs->{alias} => $source->from } ];
2316 my $seen = { %{$attrs->{seen_join}||{}} };
2318 my $join = ($attrs->{join}
2319 ? [ $attrs->{join}, $extra_join ]
2322 # we need to take the prefetch the attrs into account before we
2323 # ->resolve_join as otherwise they get lost - captainL
2324 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2328 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2331 return ($from,$seen);
2334 sub _resolved_attrs {
2336 return $self->{_attrs} if $self->{_attrs};
2338 my $attrs = { %{ $self->{attrs} || {} } };
2339 my $source = $self->result_source;
2340 my $alias = $attrs->{alias};
2342 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2345 # build columns (as long as select isn't set) into a set of as/select hashes
2346 unless ( $attrs->{select} ) {
2348 ( ref($_) eq 'HASH' )
2352 /^\Q${alias}.\E(.+)$/
2363 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2365 # add the additional columns on
2366 foreach ( 'include_columns', '+columns' ) {
2367 push @colbits, map {
2368 ( ref($_) eq 'HASH' )
2370 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2371 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2374 # start with initial select items
2375 if ( $attrs->{select} ) {
2377 ( ref $attrs->{select} eq 'ARRAY' )
2378 ? [ @{ $attrs->{select} } ]
2379 : [ $attrs->{select} ];
2383 ref $attrs->{as} eq 'ARRAY'
2384 ? [ @{ $attrs->{as} } ]
2387 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2392 # otherwise we intialise select & as to empty
2393 $attrs->{select} = [];
2397 # now add colbits to select/as
2398 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2399 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2402 if ( $adds = delete $attrs->{'+select'} ) {
2403 $adds = [$adds] unless ref $adds eq 'ARRAY';
2405 @{ $attrs->{select} },
2406 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2409 if ( $adds = delete $attrs->{'+as'} ) {
2410 $adds = [$adds] unless ref $adds eq 'ARRAY';
2411 push( @{ $attrs->{as} }, @$adds );
2414 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2416 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2417 my $join = delete $attrs->{join} || {};
2419 if ( defined $attrs->{prefetch} ) {
2420 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2424 $attrs->{from} = # have to copy here to avoid corrupting the original
2426 @{ $attrs->{from} },
2427 $source->resolve_join(
2428 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2434 $attrs->{group_by} ||= $attrs->{select}
2435 if delete $attrs->{distinct};
2436 if ( $attrs->{order_by} ) {
2437 $attrs->{order_by} = (
2438 ref( $attrs->{order_by} ) eq 'ARRAY'
2439 ? [ @{ $attrs->{order_by} } ]
2440 : [ $attrs->{order_by} ]
2444 $attrs->{order_by} = [];
2447 my $collapse = $attrs->{collapse} || {};
2448 if ( my $prefetch = delete $attrs->{prefetch} ) {
2449 $prefetch = $self->_merge_attr( {}, $prefetch );
2451 my $seen = { %{ $attrs->{seen_join} || {} } };
2452 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2454 # bring joins back to level of current class
2456 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2457 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2458 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2460 push( @{ $attrs->{order_by} }, @pre_order );
2462 $attrs->{collapse} = $collapse;
2464 if ( $attrs->{page} ) {
2465 $attrs->{offset} ||= 0;
2466 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2469 return $self->{_attrs} = $attrs;
2473 my ($self, $attr) = @_;
2475 if (ref $attr eq 'HASH') {
2476 return $self->_rollout_hash($attr);
2477 } elsif (ref $attr eq 'ARRAY') {
2478 return $self->_rollout_array($attr);
2484 sub _rollout_array {
2485 my ($self, $attr) = @_;
2488 foreach my $element (@{$attr}) {
2489 if (ref $element eq 'HASH') {
2490 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2491 } elsif (ref $element eq 'ARRAY') {
2492 # XXX - should probably recurse here
2493 push( @rolled_array, @{$self->_rollout_array($element)} );
2495 push( @rolled_array, $element );
2498 return \@rolled_array;
2502 my ($self, $attr) = @_;
2505 foreach my $key (keys %{$attr}) {
2506 push( @rolled_array, { $key => $attr->{$key} } );
2508 return \@rolled_array;
2511 sub _calculate_score {
2512 my ($self, $a, $b) = @_;
2514 if (ref $b eq 'HASH') {
2515 my ($b_key) = keys %{$b};
2516 if (ref $a eq 'HASH') {
2517 my ($a_key) = keys %{$a};
2518 if ($a_key eq $b_key) {
2519 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2524 return ($a eq $b_key) ? 1 : 0;
2527 if (ref $a eq 'HASH') {
2528 my ($a_key) = keys %{$a};
2529 return ($b eq $a_key) ? 1 : 0;
2531 return ($b eq $a) ? 1 : 0;
2537 my ($self, $orig, $import) = @_;
2539 return $import unless defined($orig);
2540 return $orig unless defined($import);
2542 $orig = $self->_rollout_attr($orig);
2543 $import = $self->_rollout_attr($import);
2546 foreach my $import_element ( @{$import} ) {
2547 # find best candidate from $orig to merge $b_element into
2548 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2549 foreach my $orig_element ( @{$orig} ) {
2550 my $score = $self->_calculate_score( $orig_element, $import_element );
2551 if ($score > $best_candidate->{score}) {
2552 $best_candidate->{position} = $position;
2553 $best_candidate->{score} = $score;
2557 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2559 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2560 push( @{$orig}, $import_element );
2562 my $orig_best = $orig->[$best_candidate->{position}];
2563 # merge orig_best and b_element together and replace original with merged
2564 if (ref $orig_best ne 'HASH') {
2565 $orig->[$best_candidate->{position}] = $import_element;
2566 } elsif (ref $import_element eq 'HASH') {
2567 my ($key) = keys %{$orig_best};
2568 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2571 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2581 $self->_source_handle($_[0]->handle);
2583 $self->_source_handle->resolve;
2587 =head2 throw_exception
2589 See L<DBIx::Class::Schema/throw_exception> for details.
2593 sub throw_exception {
2595 if (ref $self && $self->_source_handle->schema) {
2596 $self->_source_handle->schema->throw_exception(@_)
2603 # XXX: FIXME: Attributes docs need clearing up
2607 Attributes are used to refine a ResultSet in various ways when
2608 searching for data. They can be passed to any method which takes an
2609 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2612 These are in no particular order:
2618 =item Value: ( $order_by | \@order_by | \%order_by )
2622 Which column(s) to order the results by. If a single column name, or
2623 an arrayref of names is supplied, the argument is passed through
2624 directly to SQL. The hashref syntax allows for connection-agnostic
2625 specification of ordering direction:
2627 For descending order:
2629 order_by => { -desc => [qw/col1 col2 col3/] }
2631 For explicit ascending order:
2633 order_by => { -asc => 'col' }
2635 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2636 supported, although you are strongly encouraged to use the hashref
2637 syntax as outlined above.
2643 =item Value: \@columns
2647 Shortcut to request a particular set of columns to be retrieved. Each
2648 column spec may be a string (a table column name), or a hash (in which
2649 case the key is the C<as> value, and the value is used as the C<select>
2650 expression). Adds C<me.> onto the start of any column without a C<.> in
2651 it and sets C<select> from that, then auto-populates C<as> from
2652 C<select> as normal. (You may also use the C<cols> attribute, as in
2653 earlier versions of DBIC.)
2659 =item Value: \@columns
2663 Indicates additional columns to be selected from storage. Works the same
2664 as L</columns> but adds columns to the selection. (You may also use the
2665 C<include_columns> attribute, as in earlier versions of DBIC). For
2668 $schema->resultset('CD')->search(undef, {
2669 '+columns' => ['artist.name'],
2673 would return all CDs and include a 'name' column to the information
2674 passed to object inflation. Note that the 'artist' is the name of the
2675 column (or relationship) accessor, and 'name' is the name of the column
2676 accessor in the related table.
2678 =head2 include_columns
2682 =item Value: \@columns
2686 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2692 =item Value: \@select_columns
2696 Indicates which columns should be selected from the storage. You can use
2697 column names, or in the case of RDBMS back ends, function or stored procedure
2700 $rs = $schema->resultset('Employee')->search(undef, {
2703 { count => 'employeeid' },
2708 When you use function/stored procedure names and do not supply an C<as>
2709 attribute, the column names returned are storage-dependent. E.g. MySQL would
2710 return a column named C<count(employeeid)> in the above example.
2716 Indicates additional columns to be selected from storage. Works the same as
2717 L</select> but adds columns to the selection.
2725 Indicates additional column names for those added via L</+select>. See L</as>.
2733 =item Value: \@inflation_names
2737 Indicates column names for object inflation. That is, C<as>
2738 indicates the name that the column can be accessed as via the
2739 C<get_column> method (or via the object accessor, B<if one already
2740 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2742 The C<as> attribute is used in conjunction with C<select>,
2743 usually when C<select> contains one or more function or stored
2746 $rs = $schema->resultset('Employee')->search(undef, {
2749 { count => 'employeeid' }
2751 as => ['name', 'employee_count'],
2754 my $employee = $rs->first(); # get the first Employee
2756 If the object against which the search is performed already has an accessor
2757 matching a column name specified in C<as>, the value can be retrieved using
2758 the accessor as normal:
2760 my $name = $employee->name();
2762 If on the other hand an accessor does not exist in the object, you need to
2763 use C<get_column> instead:
2765 my $employee_count = $employee->get_column('employee_count');
2767 You can create your own accessors if required - see
2768 L<DBIx::Class::Manual::Cookbook> for details.
2770 Please note: This will NOT insert an C<AS employee_count> into the SQL
2771 statement produced, it is used for internal access only. Thus
2772 attempting to use the accessor in an C<order_by> clause or similar
2773 will fail miserably.
2775 To get around this limitation, you can supply literal SQL to your
2776 C<select> attibute that contains the C<AS alias> text, eg:
2778 select => [\'myfield AS alias']
2784 =item Value: ($rel_name | \@rel_names | \%rel_names)
2788 Contains a list of relationships that should be joined for this query. For
2791 # Get CDs by Nine Inch Nails
2792 my $rs = $schema->resultset('CD')->search(
2793 { 'artist.name' => 'Nine Inch Nails' },
2794 { join => 'artist' }
2797 Can also contain a hash reference to refer to the other relation's relations.
2800 package MyApp::Schema::Track;
2801 use base qw/DBIx::Class/;
2802 __PACKAGE__->table('track');
2803 __PACKAGE__->add_columns(qw/trackid cd position title/);
2804 __PACKAGE__->set_primary_key('trackid');
2805 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2808 # In your application
2809 my $rs = $schema->resultset('Artist')->search(
2810 { 'track.title' => 'Teardrop' },
2812 join => { cd => 'track' },
2813 order_by => 'artist.name',
2817 You need to use the relationship (not the table) name in conditions,
2818 because they are aliased as such. The current table is aliased as "me", so
2819 you need to use me.column_name in order to avoid ambiguity. For example:
2821 # Get CDs from 1984 with a 'Foo' track
2822 my $rs = $schema->resultset('CD')->search(
2825 'tracks.name' => 'Foo'
2827 { join => 'tracks' }
2830 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2831 similarly for a third time). For e.g.
2833 my $rs = $schema->resultset('Artist')->search({
2834 'cds.title' => 'Down to Earth',
2835 'cds_2.title' => 'Popular',
2837 join => [ qw/cds cds/ ],
2840 will return a set of all artists that have both a cd with title 'Down
2841 to Earth' and a cd with title 'Popular'.
2843 If you want to fetch related objects from other tables as well, see C<prefetch>
2846 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2852 =item Value: ($rel_name | \@rel_names | \%rel_names)
2856 Contains one or more relationships that should be fetched along with
2857 the main query (when they are accessed afterwards the data will
2858 already be available, without extra queries to the database). This is
2859 useful for when you know you will need the related objects, because it
2860 saves at least one query:
2862 my $rs = $schema->resultset('Tag')->search(
2871 The initial search results in SQL like the following:
2873 SELECT tag.*, cd.*, artist.* FROM tag
2874 JOIN cd ON tag.cd = cd.cdid
2875 JOIN artist ON cd.artist = artist.artistid
2877 L<DBIx::Class> has no need to go back to the database when we access the
2878 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2881 Simple prefetches will be joined automatically, so there is no need
2882 for a C<join> attribute in the above search.
2884 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2885 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2886 with an accessor type of 'single' or 'filter'). A more complex example that
2887 prefetches an artists cds, the tracks on those cds, and the tags associted
2888 with that artist is given below (assuming many-to-many from artists to tags):
2890 my $rs = $schema->resultset('Artist')->search(
2894 { cds => 'tracks' },
2895 { artist_tags => 'tags' }
2901 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2902 attributes will be ignored.
2912 Makes the resultset paged and specifies the page to retrieve. Effectively
2913 identical to creating a non-pages resultset and then calling ->page($page)
2916 If L<rows> attribute is not specified it defualts to 10 rows per page.
2918 When you have a paged resultset, L</count> will only return the number
2919 of rows in the page. To get the total, use the L</pager> and call
2920 C<total_entries> on it.
2930 Specifes the maximum number of rows for direct retrieval or the number of
2931 rows per page if the page attribute or method is used.
2937 =item Value: $offset
2941 Specifies the (zero-based) row number for the first row to be returned, or the
2942 of the first row of the first page if paging is used.
2948 =item Value: \@columns
2952 A arrayref of columns to group by. Can include columns of joined tables.
2954 group_by => [qw/ column1 column2 ... /]
2960 =item Value: $condition
2964 HAVING is a select statement attribute that is applied between GROUP BY and
2965 ORDER BY. It is applied to the after the grouping calculations have been
2968 having => { 'count(employee)' => { '>=', 100 } }
2974 =item Value: (0 | 1)
2978 Set to 1 to group by all columns.
2984 Adds to the WHERE clause.
2986 # only return rows WHERE deleted IS NULL for all searches
2987 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
2989 Can be overridden by passing C<{ where => undef }> as an attribute
2996 Set to 1 to cache search results. This prevents extra SQL queries if you
2997 revisit rows in your ResultSet:
2999 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3001 while( my $artist = $resultset->next ) {
3005 $rs->first; # without cache, this would issue a query
3007 By default, searches are not cached.
3009 For more examples of using these attributes, see
3010 L<DBIx::Class::Manual::Cookbook>.
3016 =item Value: \@from_clause
3020 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3021 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3024 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3026 C<join> will usually do what you need and it is strongly recommended that you
3027 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3028 And we really do mean "cannot", not just tried and failed. Attempting to use
3029 this because you're having problems with C<join> is like trying to use x86
3030 ASM because you've got a syntax error in your C. Trust us on this.
3032 Now, if you're still really, really sure you need to use this (and if you're
3033 not 100% sure, ask the mailing list first), here's an explanation of how this
3036 The syntax is as follows -
3039 { <alias1> => <table1> },
3041 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3042 [], # nested JOIN (optional)
3043 { <table1.column1> => <table2.column2>, ... (more conditions) },
3045 # More of the above [ ] may follow for additional joins
3052 ON <table1.column1> = <table2.column2>
3053 <more joins may follow>
3055 An easy way to follow the examples below is to remember the following:
3057 Anything inside "[]" is a JOIN
3058 Anything inside "{}" is a condition for the enclosing JOIN
3060 The following examples utilize a "person" table in a family tree application.
3061 In order to express parent->child relationships, this table is self-joined:
3063 # Person->belongs_to('father' => 'Person');
3064 # Person->belongs_to('mother' => 'Person');
3066 C<from> can be used to nest joins. Here we return all children with a father,
3067 then search against all mothers of those children:
3069 $rs = $schema->resultset('Person')->search(
3072 alias => 'mother', # alias columns in accordance with "from"
3074 { mother => 'person' },
3077 { child => 'person' },
3079 { father => 'person' },
3080 { 'father.person_id' => 'child.father_id' }
3083 { 'mother.person_id' => 'child.mother_id' }
3090 # SELECT mother.* FROM person mother
3093 # JOIN person father
3094 # ON ( father.person_id = child.father_id )
3096 # ON ( mother.person_id = child.mother_id )
3098 The type of any join can be controlled manually. To search against only people
3099 with a father in the person table, we could explicitly use C<INNER JOIN>:
3101 $rs = $schema->resultset('Person')->search(
3104 alias => 'child', # alias columns in accordance with "from"
3106 { child => 'person' },
3108 { father => 'person', -join_type => 'inner' },
3109 { 'father.id' => 'child.father_id' }
3116 # SELECT child.* FROM person child
3117 # INNER JOIN person father ON child.father_id = father.id
3119 If you need to express really complex joins or you need a subselect, you
3120 can supply literal SQL to C<from> via a scalar reference. In this case
3121 the contents of the scalar will replace the table name asscoiated with the
3124 WARNING: This technique might very well not work as expected on chained
3125 searches - you have been warned.
3127 # Assuming the Event resultsource is defined as:
3129 MySchema::Event->add_columns (
3132 is_auto_increment => 1,
3141 MySchema::Event->set_primary_key ('sequence');
3143 # This will get back the latest event for every location. The column
3144 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3145 # combo to limit the resultset
3147 $rs = $schema->resultset('Event');
3148 $table = $rs->result_source->name;
3149 $latest = $rs->search (
3152 (SELECT e1.* FROM $table e1
3154 ON e1.location = e2.location
3155 AND e1.sequence < e2.sequence
3156 WHERE e2.sequence is NULL
3161 # Equivalent SQL (with the DBIC chunks added):
3163 SELECT me.sequence, me.location, me.type FROM
3164 (SELECT e1.* FROM events e1
3166 ON e1.location = e2.location
3167 AND e1.sequence < e2.sequence
3168 WHERE e2.sequence is NULL
3175 =item Value: ( 'update' | 'shared' )
3179 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT