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 also incorporates an implicit iterator. L</next> and L</reset>
50 can be used to walk through all the L<DBIx::Class::Row>s the ResultSet
53 The query that the ResultSet represents is B<only> executed against
54 the database when these methods are called:
55 L</find> L</next> L</all> L</first> L</single> L</count>
59 =head2 Chaining resultsets
61 Let's say you've got a query that needs to be run to return some data
62 to the user. But, you have an authorization system in place that
63 prevents certain users from seeing certain information. So, you want
64 to construct the basic query in one method, but add constraints to it in
69 my $request = $self->get_request; # Get a request object somehow.
70 my $schema = $self->get_schema; # Get the DBIC schema object somehow.
72 my $cd_rs = $schema->resultset('CD')->search({
73 title => $request->param('title'),
74 year => $request->param('year'),
77 $self->apply_security_policy( $cd_rs );
82 sub apply_security_policy {
91 =head3 Resolving conditions and attributes
93 When a resultset is chained from another resultset, conditions and
94 attributes with the same keys need resolving.
96 L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
97 into the existing ones from the original resultset.
99 The L</where>, L</having> attribute, and any search conditions are
100 merged with an SQL C<AND> to the existing condition from the original
103 All other attributes are overridden by any new ones supplied in the
106 =head2 Multiple queries
108 Since a resultset just defines a query, you can do all sorts of
109 things with it with the same object.
111 # Don't hit the DB yet.
112 my $cd_rs = $schema->resultset('CD')->search({
113 title => 'something',
117 # Each of these hits the DB individually.
118 my $count = $cd_rs->count;
119 my $most_recent = $cd_rs->get_column('date_released')->max();
120 my @records = $cd_rs->all;
122 And it's not just limited to SELECT statements.
128 $cd_rs->create({ artist => 'Fred' });
130 Which is the same as:
132 $schema->resultset('CD')->create({
133 title => 'something',
138 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
142 If a resultset is used in a numeric context it returns the L</count>.
143 However, if it is used in a booleand context it is always true. So if
144 you want to check if a resultset has any results use C<if $rs != 0>.
145 C<if $rs> will always be true.
153 =item Arguments: $source, \%$attrs
155 =item Return Value: $rs
159 The resultset constructor. Takes a source object (usually a
160 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
161 L</ATTRIBUTES> below). Does not perform any queries -- these are
162 executed as needed by the other methods.
164 Generally you won't need to construct a resultset manually. You'll
165 automatically get one from e.g. a L</search> called in scalar context:
167 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
169 IMPORTANT: If called on an object, proxies to new_result instead so
171 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
173 will return a CD object, not a ResultSet.
179 return $class->new_result(@_) if ref $class;
181 my ($source, $attrs) = @_;
182 $source = $source->handle
183 unless $source->isa('DBIx::Class::ResultSourceHandle');
184 $attrs = { %{$attrs||{}} };
186 if ($attrs->{page}) {
187 $attrs->{rows} ||= 10;
190 $attrs->{alias} ||= 'me';
192 # Creation of {} and bless separated to mitigate RH perl bug
193 # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
195 _source_handle => $source,
196 cond => $attrs->{where},
205 $attrs->{result_class} || $source->resolve->result_class
215 =item Arguments: $cond, \%attrs?
217 =item Return Value: $resultset (scalar context), @row_objs (list context)
221 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
222 my $new_rs = $cd_rs->search({ year => 2005 });
224 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
225 # year = 2005 OR year = 2004
227 If you need to pass in additional attributes but no additional condition,
228 call it as C<search(undef, \%attrs)>.
230 # "SELECT name, artistid FROM $artist_table"
231 my @all_artists = $schema->resultset('Artist')->search(undef, {
232 columns => [qw/name artistid/],
235 For a list of attributes that can be passed to C<search>, see
236 L</ATTRIBUTES>. For more examples of using this function, see
237 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
238 documentation for the first argument, see L<SQL::Abstract>.
240 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
246 my $rs = $self->search_rs( @_ );
247 return (wantarray ? $rs->all : $rs);
254 =item Arguments: $cond, \%attrs?
256 =item Return Value: $resultset
260 This method does the same exact thing as search() except it will
261 always return a resultset, even in list context.
268 # Special-case handling for (undef, undef).
269 if ( @_ == 2 && !defined $_[1] && !defined $_[0] ) {
274 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
275 my $our_attrs = { %{$self->{attrs}} };
276 my $having = delete $our_attrs->{having};
277 my $where = delete $our_attrs->{where};
281 my %safe = (alias => 1, cache => 1);
284 (@_ && defined($_[0])) # @_ == () or (undef)
286 (keys %$attrs # empty attrs or only 'safe' attrs
287 && List::Util::first { !$safe{$_} } keys %$attrs)
289 # no search, effectively just a clone
290 $rows = $self->get_cache;
293 my $new_attrs = { %{$our_attrs}, %{$attrs} };
295 # merge new attrs into inherited
296 foreach my $key (qw/join prefetch +select +as bind/) {
297 next unless exists $attrs->{$key};
298 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
303 (@_ == 1 || ref $_[0] eq "HASH")
305 (ref $_[0] eq 'HASH')
307 (keys %{ $_[0] } > 0)
315 ? $self->throw_exception("Odd number of arguments to search")
322 if (defined $where) {
323 $new_attrs->{where} = (
324 defined $new_attrs->{where}
327 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
328 } $where, $new_attrs->{where}
335 $new_attrs->{where} = (
336 defined $new_attrs->{where}
339 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
340 } $cond, $new_attrs->{where}
346 if (defined $having) {
347 $new_attrs->{having} = (
348 defined $new_attrs->{having}
351 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
352 } $having, $new_attrs->{having}
358 my $rs = (ref $self)->new($self->result_source, $new_attrs);
360 $rs->set_cache($rows);
365 =head2 search_literal
369 =item Arguments: $sql_fragment, @bind_values
371 =item Return Value: $resultset (scalar context), @row_objs (list context)
375 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
376 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
378 Pass a literal chunk of SQL to be added to the conditional part of the
381 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
382 only be used in that context. C<search_literal> is a convenience method.
383 It is equivalent to calling $schema->search(\[]), but if you want to ensure
384 columns are bound correctly, use C<search>.
386 Example of how to use C<search> instead of C<search_literal>
388 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
389 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
392 See L<DBIx::Class::Manual::Cookbook/Searching> and
393 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
394 require C<search_literal>.
399 my ($self, $sql, @bind) = @_;
401 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
404 return $self->search(\[ $sql, map [ __DUMMY__ => $_ ], @bind ], ($attr || () ));
411 =item Arguments: @values | \%cols, \%attrs?
413 =item Return Value: $row_object | undef
417 Finds a row based on its primary key or unique constraint. For example, to find
418 a row by its primary key:
420 my $cd = $schema->resultset('CD')->find(5);
422 You can also find a row by a specific unique constraint using the C<key>
423 attribute. For example:
425 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
426 key => 'cd_artist_title'
429 Additionally, you can specify the columns explicitly by name:
431 my $cd = $schema->resultset('CD')->find(
433 artist => 'Massive Attack',
434 title => 'Mezzanine',
436 { key => 'cd_artist_title' }
439 If the C<key> is specified as C<primary>, it searches only on the primary key.
441 If no C<key> is specified, it searches on all unique constraints defined on the
442 source for which column data is provided, including the primary key.
444 If your table does not have a primary key, you B<must> provide a value for the
445 C<key> attribute matching one of the unique constraints on the source.
447 In addition to C<key>, L</find> recognizes and applies standard
448 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
450 Note: If your query does not return only one row, a warning is generated:
452 Query returned more than one row
454 See also L</find_or_create> and L</update_or_create>. For information on how to
455 declare unique constraints, see
456 L<DBIx::Class::ResultSource/add_unique_constraint>.
462 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
464 # Default to the primary key, but allow a specific key
465 my @cols = exists $attrs->{key}
466 ? $self->result_source->unique_constraint_columns($attrs->{key})
467 : $self->result_source->primary_columns;
468 $self->throw_exception(
469 "Can't find unless a primary key is defined or unique constraint is specified"
472 # Parse out a hashref from input
474 if (ref $_[0] eq 'HASH') {
475 $input_query = { %{$_[0]} };
477 elsif (@_ == @cols) {
479 @{$input_query}{@cols} = @_;
482 # Compatibility: Allow e.g. find(id => $value)
483 carp "Find by key => value deprecated; please use a hashref instead";
487 my (%related, $info);
489 KEY: foreach my $key (keys %$input_query) {
490 if (ref($input_query->{$key})
491 && ($info = $self->result_source->relationship_info($key))) {
492 my $val = delete $input_query->{$key};
493 next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
494 my $rel_q = $self->result_source->_resolve_condition(
495 $info->{cond}, $val, $key
497 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
498 @related{keys %$rel_q} = values %$rel_q;
501 if (my @keys = keys %related) {
502 @{$input_query}{@keys} = values %related;
506 # Build the final query: Default to the disjunction of the unique queries,
507 # but allow the input query in case the ResultSet defines the query or the
508 # user is abusing find
509 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
511 if (exists $attrs->{key}) {
512 my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key});
513 my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
514 $query = $self->_add_alias($unique_query, $alias);
517 my @unique_queries = $self->_unique_queries($input_query, $attrs);
518 $query = @unique_queries
519 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
520 : $self->_add_alias($input_query, $alias);
525 my $rs = $self->search($query, $attrs);
526 if (keys %{$rs->_resolved_attrs->{collapse}}) {
528 carp "Query returned more than one row" if $rs->next;
536 if (keys %{$self->_resolved_attrs->{collapse}}) {
537 my $rs = $self->search($query);
539 carp "Query returned more than one row" if $rs->next;
543 return $self->single($query);
550 # Add the specified alias to the specified query hash. A copy is made so the
551 # original query is not modified.
554 my ($self, $query, $alias) = @_;
556 my %aliased = %$query;
557 foreach my $col (grep { ! m/\./ } keys %aliased) {
558 $aliased{"$alias.$col"} = delete $aliased{$col};
566 # Build a list of queries which satisfy unique constraints.
568 sub _unique_queries {
569 my ($self, $query, $attrs) = @_;
571 my @constraint_names = exists $attrs->{key}
573 : $self->result_source->unique_constraint_names;
575 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
576 my $num_where = scalar keys %$where;
579 foreach my $name (@constraint_names) {
580 my @unique_cols = $self->result_source->unique_constraint_columns($name);
581 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
583 my $num_cols = scalar @unique_cols;
584 my $num_query = scalar keys %$unique_query;
586 my $total = $num_query + $num_where;
587 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
588 # The query is either unique on its own or is unique in combination with
589 # the existing where clause
590 push @unique_queries, $unique_query;
594 return @unique_queries;
597 # _build_unique_query
599 # Constrain the specified query hash based on the specified column names.
601 sub _build_unique_query {
602 my ($self, $query, $unique_cols) = @_;
605 map { $_ => $query->{$_} }
606 grep { exists $query->{$_} }
611 =head2 search_related
615 =item Arguments: $rel, $cond, \%attrs?
617 =item Return Value: $new_resultset
621 $new_rs = $cd_rs->search_related('artist', {
625 Searches the specified relationship, optionally specifying a condition and
626 attributes for matching records. See L</ATTRIBUTES> for more information.
631 return shift->related_resultset(shift)->search(@_);
634 =head2 search_related_rs
636 This method works exactly the same as search_related, except that
637 it guarantees a restultset, even in list context.
641 sub search_related_rs {
642 return shift->related_resultset(shift)->search_rs(@_);
649 =item Arguments: none
651 =item Return Value: $cursor
655 Returns a storage-driven cursor to the given resultset. See
656 L<DBIx::Class::Cursor> for more information.
663 my $attrs = $self->_resolved_attrs_copy;
665 return $self->{cursor}
666 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
667 $attrs->{where},$attrs);
674 =item Arguments: $cond?
676 =item Return Value: $row_object?
680 my $cd = $schema->resultset('CD')->single({ year => 2001 });
682 Inflates the first result without creating a cursor if the resultset has
683 any records in it; if not returns nothing. Used by L</find> as a lean version of
686 While this method can take an optional search condition (just like L</search>)
687 being a fast-code-path it does not recognize search attributes. If you need to
688 add extra joins or similar, call L</search> and then chain-call L</single> on the
689 L<DBIx::Class::ResultSet> returned.
695 As of 0.08100, this method enforces the assumption that the preceeding
696 query returns only one row. If more than one row is returned, you will receive
699 Query returned more than one row
701 In this case, you should be using L</first> or L</find> instead, or if you really
702 know what you are doing, use the L</rows> attribute to explicitly limit the size
710 my ($self, $where) = @_;
712 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
715 my $attrs = $self->_resolved_attrs_copy;
718 if (defined $attrs->{where}) {
721 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
722 $where, delete $attrs->{where} ]
725 $attrs->{where} = $where;
729 # XXX: Disabled since it doesn't infer uniqueness in all cases
730 # unless ($self->_is_unique_query($attrs->{where})) {
731 # carp "Query not guaranteed to return a single row"
732 # . "; please declare your unique constraints or use search instead";
735 my @data = $self->result_source->storage->select_single(
736 $attrs->{from}, $attrs->{select},
737 $attrs->{where}, $attrs
740 return (@data ? ($self->_construct_object(@data))[0] : undef);
746 # Try to determine if the specified query is guaranteed to be unique, based on
747 # the declared unique constraints.
749 sub _is_unique_query {
750 my ($self, $query) = @_;
752 my $collapsed = $self->_collapse_query($query);
753 my $alias = $self->{attrs}{alias};
755 foreach my $name ($self->result_source->unique_constraint_names) {
756 my @unique_cols = map {
758 } $self->result_source->unique_constraint_columns($name);
760 # Count the values for each unique column
761 my %seen = map { $_ => 0 } @unique_cols;
763 foreach my $key (keys %$collapsed) {
764 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
765 next unless exists $seen{$aliased}; # Additional constraints are okay
766 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
769 # If we get 0 or more than 1 value for a column, it's not necessarily unique
770 return 1 unless grep { $_ != 1 } values %seen;
778 # Recursively collapse the query, accumulating values for each column.
780 sub _collapse_query {
781 my ($self, $query, $collapsed) = @_;
785 if (ref $query eq 'ARRAY') {
786 foreach my $subquery (@$query) {
787 next unless ref $subquery; # -or
788 $collapsed = $self->_collapse_query($subquery, $collapsed);
791 elsif (ref $query eq 'HASH') {
792 if (keys %$query and (keys %$query)[0] eq '-and') {
793 foreach my $subquery (@{$query->{-and}}) {
794 $collapsed = $self->_collapse_query($subquery, $collapsed);
798 foreach my $col (keys %$query) {
799 my $value = $query->{$col};
800 $collapsed->{$col}{$value}++;
812 =item Arguments: $cond?
814 =item Return Value: $resultsetcolumn
818 my $max_length = $rs->get_column('length')->max;
820 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
825 my ($self, $column) = @_;
826 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
834 =item Arguments: $cond, \%attrs?
836 =item Return Value: $resultset (scalar context), @row_objs (list context)
840 # WHERE title LIKE '%blue%'
841 $cd_rs = $rs->search_like({ title => '%blue%'});
843 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
844 that this is simply a convenience method retained for ex Class::DBI users.
845 You most likely want to use L</search> with specific operators.
847 For more information, see L<DBIx::Class::Manual::Cookbook>.
849 This method is deprecated and will be removed in 0.09. Use L</search()>
850 instead. An example conversion is:
852 ->search_like({ foo => 'bar' });
856 ->search({ foo => { like => 'bar' } });
863 'search_like() is deprecated and will be removed in DBIC version 0.09.'
864 .' Instead use ->search({ x => { -like => "y%" } })'
865 .' (note the outer pair of {}s - they are important!)'
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: $result_class
1106 An accessor for the class to use when creating row objects. Defaults to
1107 C<< result_source->result_class >> - which in most cases is the name of the
1108 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1110 Note that changing the result_class will also remove any components
1111 that were originally loaded in the source class via
1112 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1113 in the original source class will not run.
1118 my ($self, $result_class) = @_;
1119 if ($result_class) {
1120 $self->ensure_class_loaded($result_class);
1121 $self->_result_class($result_class);
1123 $self->_result_class;
1130 =item Arguments: $cond, \%attrs??
1132 =item Return Value: $count
1136 Performs an SQL C<COUNT> with the same query as the resultset was built
1137 with to find the number of elements. Passing arguments is equivalent to
1138 C<< $rs->search ($cond, \%attrs)->count >>
1144 return $self->search(@_)->count if @_ and defined $_[0];
1145 return scalar @{ $self->get_cache } if $self->get_cache;
1147 my $meth = $self->_has_attr (qw/prefetch collapse distinct group_by/)
1152 my $attrs = $self->_resolved_attrs_copy;
1153 my $rsrc = $self->result_source;
1155 return $rsrc->storage->$meth ($rsrc, $attrs);
1162 =head2 count_literal
1166 =item Arguments: $sql_fragment, @bind_values
1168 =item Return Value: $count
1172 Counts the results in a literal query. Equivalent to calling L</search_literal>
1173 with the passed arguments, then L</count>.
1177 sub count_literal { shift->search_literal(@_)->count; }
1183 =item Arguments: none
1185 =item Return Value: @objects
1189 Returns all elements in the resultset. Called implicitly if the resultset
1190 is returned in list context.
1197 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1200 return @{ $self->get_cache } if $self->get_cache;
1204 # TODO: don't call resolve here
1205 if (keys %{$self->_resolved_attrs->{collapse}}) {
1206 # if ($self->{attrs}{prefetch}) {
1207 # Using $self->cursor->all is really just an optimisation.
1208 # If we're collapsing has_many prefetches it probably makes
1209 # very little difference, and this is cleaner than hacking
1210 # _construct_object to survive the approach
1211 my @row = $self->cursor->next;
1213 push(@obj, $self->_construct_object(@row));
1214 @row = (exists $self->{stashed_row}
1215 ? @{delete $self->{stashed_row}}
1216 : $self->cursor->next);
1219 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1222 $self->set_cache(\@obj) if $self->{attrs}{cache};
1230 =item Arguments: none
1232 =item Return Value: $self
1236 Resets the resultset's cursor, so you can iterate through the elements again.
1242 delete $self->{_attrs} if exists $self->{_attrs};
1243 $self->{all_cache_position} = 0;
1244 $self->cursor->reset;
1252 =item Arguments: none
1254 =item Return Value: $object?
1258 Resets the resultset and returns an object for the first result (if the
1259 resultset returns anything).
1264 return $_[0]->reset->next;
1270 # Determines whether and what type of subquery is required for the $rs operation.
1271 # If grouping is necessary either supplies its own, or verifies the current one
1272 # After all is done delegates to the proper storage method.
1274 sub _rs_update_delete {
1275 my ($self, $op, $values) = @_;
1277 my $rsrc = $self->result_source;
1279 my $needs_group_by_subq = $self->_has_attr (qw/prefetch distinct join seen_join group_by/);
1280 my $needs_subq = $self->_has_attr (qw/row offset page/);
1282 if ($needs_group_by_subq or $needs_subq) {
1284 # make a new $rs selecting only the PKs (that's all we really need)
1285 my $attrs = $self->_resolved_attrs_copy;
1287 delete $attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns/;
1288 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
1290 if ($needs_group_by_subq) {
1291 # make sure no group_by was supplied, or if there is one - make sure it matches
1292 # the columns compiled above perfectly. Anything else can not be sanely executed
1293 # on most databases so croak right then and there
1295 if (my $g = $attrs->{group_by}) {
1296 my @current_group_by = map
1297 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1298 (ref $g eq 'ARRAY' ? @$g : $g );
1301 join ("\x00", sort @current_group_by)
1303 join ("\x00", sort @{$attrs->{columns}} )
1305 $self->throw_exception (
1306 "You have just attempted a $op operation on a resultset which does group_by"
1307 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1308 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1309 . ' kind of queries. Please retry the operation with a modified group_by or'
1310 . ' without using one at all.'
1315 $attrs->{group_by} = $attrs->{columns};
1319 my $subrs = (ref $self)->new($rsrc, $attrs);
1321 return $self->result_source->storage->_subq_update_delete($subrs, $op, $values);
1324 return $rsrc->storage->$op(
1326 $op eq 'update' ? $values : (),
1327 $self->_cond_for_update_delete,
1333 # _cond_for_update_delete
1335 # update/delete require the condition to be modified to handle
1336 # the differing SQL syntax available. This transforms the $self->{cond}
1337 # appropriately, returning the new condition.
1339 sub _cond_for_update_delete {
1340 my ($self, $full_cond) = @_;
1343 $full_cond ||= $self->{cond};
1344 # No-op. No condition, we're updating/deleting everything
1345 return $cond unless ref $full_cond;
1347 if (ref $full_cond eq 'ARRAY') {
1351 foreach my $key (keys %{$_}) {
1353 $hash{$1} = $_->{$key};
1359 elsif (ref $full_cond eq 'HASH') {
1360 if ((keys %{$full_cond})[0] eq '-and') {
1362 my @cond = @{$full_cond->{-and}};
1363 for (my $i = 0; $i < @cond; $i++) {
1364 my $entry = $cond[$i];
1366 if (ref $entry eq 'HASH') {
1367 $hash = $self->_cond_for_update_delete($entry);
1370 $entry =~ /([^.]+)$/;
1371 $hash->{$1} = $cond[++$i];
1373 push @{$cond->{-and}}, $hash;
1377 foreach my $key (keys %{$full_cond}) {
1379 $cond->{$1} = $full_cond->{$key};
1384 $self->throw_exception("Can't update/delete on resultset with condition unless hash or array");
1395 =item Arguments: \%values
1397 =item Return Value: $storage_rv
1401 Sets the specified columns in the resultset to the supplied values in a
1402 single query. Return value will be true if the update succeeded or false
1403 if no records were updated; exact type of success value is storage-dependent.
1408 my ($self, $values) = @_;
1409 $self->throw_exception('Values for update must be a hash')
1410 unless ref $values eq 'HASH';
1412 return $self->_rs_update_delete ('update', $values);
1419 =item Arguments: \%values
1421 =item Return Value: 1
1425 Fetches all objects and updates them one at a time. Note that C<update_all>
1426 will run DBIC cascade triggers, while L</update> will not.
1431 my ($self, $values) = @_;
1432 $self->throw_exception('Values for update_all must be a hash')
1433 unless ref $values eq 'HASH';
1434 foreach my $obj ($self->all) {
1435 $obj->set_columns($values)->update;
1444 =item Arguments: none
1446 =item Return Value: $storage_rv
1450 Deletes the contents of the resultset from its result source. Note that this
1451 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1452 to run. See also L<DBIx::Class::Row/delete>.
1454 Return value will be the amount of rows deleted; exact type of return value
1455 is storage-dependent.
1461 $self->throw_exception('delete does not accept any arguments')
1464 return $self->_rs_update_delete ('delete');
1471 =item Arguments: none
1473 =item Return Value: 1
1477 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1478 will run DBIC cascade triggers, while L</delete> will not.
1484 $self->throw_exception('delete_all does not accept any arguments')
1487 $_->delete for $self->all;
1495 =item Arguments: \@data;
1499 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1500 For the arrayref of hashrefs style each hashref should be a structure suitable
1501 forsubmitting to a $resultset->create(...) method.
1503 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1504 to insert the data, as this is a faster method.
1506 Otherwise, each set of data is inserted into the database using
1507 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1508 objects is returned.
1510 Example: Assuming an Artist Class that has many CDs Classes relating:
1512 my $Artist_rs = $schema->resultset("Artist");
1514 ## Void Context Example
1515 $Artist_rs->populate([
1516 { artistid => 4, name => 'Manufactured Crap', cds => [
1517 { title => 'My First CD', year => 2006 },
1518 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1521 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1522 { title => 'My parents sold me to a record company' ,year => 2005 },
1523 { title => 'Why Am I So Ugly?', year => 2006 },
1524 { title => 'I Got Surgery and am now Popular', year => 2007 }
1529 ## Array Context Example
1530 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1531 { name => "Artist One"},
1532 { name => "Artist Two"},
1533 { name => "Artist Three", cds=> [
1534 { title => "First CD", year => 2007},
1535 { title => "Second CD", year => 2008},
1539 print $ArtistOne->name; ## response is 'Artist One'
1540 print $ArtistThree->cds->count ## reponse is '2'
1542 For the arrayref of arrayrefs style, the first element should be a list of the
1543 fieldsnames to which the remaining elements are rows being inserted. For
1546 $Arstist_rs->populate([
1547 [qw/artistid name/],
1548 [100, 'A Formally Unknown Singer'],
1549 [101, 'A singer that jumped the shark two albums ago'],
1550 [102, 'An actually cool singer.'],
1553 Please note an important effect on your data when choosing between void and
1554 wantarray context. Since void context goes straight to C<insert_bulk> in
1555 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1556 C<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1557 create primary keys for you, you will find that your PKs are empty. In this
1558 case you will have to use the wantarray context in order to create those
1564 my $self = shift @_;
1565 my $data = ref $_[0][0] eq 'HASH'
1566 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1567 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1569 if(defined wantarray) {
1571 foreach my $item (@$data) {
1572 push(@created, $self->create($item));
1576 my ($first, @rest) = @$data;
1578 my @names = grep {!ref $first->{$_}} keys %$first;
1579 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1580 my @pks = $self->result_source->primary_columns;
1582 ## do the belongs_to relationships
1583 foreach my $index (0..$#$data) {
1585 # delegate to create() for any dataset without primary keys with specified relationships
1586 if (grep { !defined $data->[$index]->{$_} } @pks ) {
1588 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
1589 my @ret = $self->populate($data);
1595 foreach my $rel (@rels) {
1596 next unless ref $data->[$index]->{$rel} eq "HASH";
1597 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1598 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1599 my $related = $result->result_source->_resolve_condition(
1600 $result->result_source->relationship_info($reverse)->{cond},
1605 delete $data->[$index]->{$rel};
1606 $data->[$index] = {%{$data->[$index]}, %$related};
1608 push @names, keys %$related if $index == 0;
1612 ## do bulk insert on current row
1613 my @values = map { [ @$_{@names} ] } @$data;
1615 $self->result_source->storage->insert_bulk(
1616 $self->result_source,
1621 ## do the has_many relationships
1622 foreach my $item (@$data) {
1624 foreach my $rel (@rels) {
1625 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1627 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1628 || $self->throw_exception('Cannot find the relating object.');
1630 my $child = $parent->$rel;
1632 my $related = $child->result_source->_resolve_condition(
1633 $parent->result_source->relationship_info($rel)->{cond},
1638 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1639 my @populate = map { {%$_, %$related} } @rows_to_add;
1641 $child->populate( \@populate );
1647 =head2 _normalize_populate_args ($args)
1649 Private method used by L</populate> to normalize its incoming arguments. Factored
1650 out in case you want to subclass and accept new argument structures to the
1651 L</populate> method.
1655 sub _normalize_populate_args {
1656 my ($self, $data) = @_;
1657 my @names = @{shift(@$data)};
1658 my @results_to_create;
1659 foreach my $datum (@$data) {
1660 my %result_to_create;
1661 foreach my $index (0..$#names) {
1662 $result_to_create{$names[$index]} = $$datum[$index];
1664 push @results_to_create, \%result_to_create;
1666 return \@results_to_create;
1673 =item Arguments: none
1675 =item Return Value: $pager
1679 Return Value a L<Data::Page> object for the current resultset. Only makes
1680 sense for queries with a C<page> attribute.
1682 To get the full count of entries for a paged resultset, call
1683 C<total_entries> on the L<Data::Page> object.
1690 return $self->{pager} if $self->{pager};
1692 my $attrs = $self->{attrs};
1693 $self->throw_exception("Can't create pager for non-paged rs")
1694 unless $self->{attrs}{page};
1695 $attrs->{rows} ||= 10;
1697 # throw away the paging flags and re-run the count (possibly
1698 # with a subselect) to get the real total count
1699 my $count_attrs = { %$attrs };
1700 delete $count_attrs->{$_} for qw/rows offset page pager/;
1701 my $total_count = (ref $self)->new($self->result_source, $count_attrs)->count;
1703 return $self->{pager} = Data::Page->new(
1706 $self->{attrs}{page}
1714 =item Arguments: $page_number
1716 =item Return Value: $rs
1720 Returns a resultset for the $page_number page of the resultset on which page
1721 is called, where each page contains a number of rows equal to the 'rows'
1722 attribute set on the resultset (10 by default).
1727 my ($self, $page) = @_;
1728 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1735 =item Arguments: \%vals
1737 =item Return Value: $rowobject
1741 Creates a new row object in the resultset's result class and returns
1742 it. The row is not inserted into the database at this point, call
1743 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1744 will tell you whether the row object has been inserted or not.
1746 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1751 my ($self, $values) = @_;
1752 $self->throw_exception( "new_result needs a hash" )
1753 unless (ref $values eq 'HASH');
1756 my $alias = $self->{attrs}{alias};
1759 defined $self->{cond}
1760 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1762 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1763 $new{-from_resultset} = [ keys %new ] if keys %new;
1765 $self->throw_exception(
1766 "Can't abstract implicit construct, condition not a hash"
1767 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1769 my $collapsed_cond = (
1771 ? $self->_collapse_cond($self->{cond})
1775 # precendence must be given to passed values over values inherited from
1776 # the cond, so the order here is important.
1777 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1778 while( my($col,$value) = each %implied ){
1779 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1780 $new{$col} = $value->{'='};
1783 $new{$col} = $value if $self->_is_deterministic_value($value);
1789 %{ $self->_remove_alias($values, $alias) },
1790 -source_handle => $self->_source_handle,
1791 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1794 return $self->result_class->new(\%new);
1797 # _is_deterministic_value
1799 # Make an effor to strip non-deterministic values from the condition,
1800 # to make sure new_result chokes less
1802 sub _is_deterministic_value {
1805 my $ref_type = ref $value;
1806 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1807 return 1 if Scalar::Util::blessed($value);
1813 # determines if the resultset defines at least one
1814 # of the attributes supplied
1816 # used to determine if a subquery is neccessary
1819 my ($self, @attr_names) = @_;
1821 my $attrs = $self->_resolved_attrs;
1825 for my $n (@attr_names) {
1826 ++$join_check_req if $n =~ /join/;
1828 my $attr = $attrs->{$n};
1830 next if not defined $attr;
1832 if (ref $attr eq 'HASH') {
1833 return 1 if keys %$attr;
1835 elsif (ref $attr eq 'ARRAY') {
1843 # a join can be expressed as a multi-level from
1847 ref $attrs->{from} eq 'ARRAY'
1849 @{$attrs->{from}} > 1
1857 # Recursively collapse the condition.
1859 sub _collapse_cond {
1860 my ($self, $cond, $collapsed) = @_;
1864 if (ref $cond eq 'ARRAY') {
1865 foreach my $subcond (@$cond) {
1866 next unless ref $subcond; # -or
1867 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1870 elsif (ref $cond eq 'HASH') {
1871 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1872 foreach my $subcond (@{$cond->{-and}}) {
1873 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1877 foreach my $col (keys %$cond) {
1878 my $value = $cond->{$col};
1879 $collapsed->{$col} = $value;
1889 # Remove the specified alias from the specified query hash. A copy is made so
1890 # the original query is not modified.
1893 my ($self, $query, $alias) = @_;
1895 my %orig = %{ $query || {} };
1898 foreach my $key (keys %orig) {
1900 $unaliased{$key} = $orig{$key};
1903 $unaliased{$1} = $orig{$key}
1904 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1910 =head2 as_query (EXPERIMENTAL)
1914 =item Arguments: none
1916 =item Return Value: \[ $sql, @bind ]
1920 Returns the SQL query and bind vars associated with the invocant.
1922 This is generally used as the RHS for a subquery.
1924 B<NOTE>: This feature is still experimental.
1928 sub as_query { return shift->cursor->as_query(@_) }
1934 =item Arguments: \%vals, \%attrs?
1936 =item Return Value: $rowobject
1940 my $artist = $schema->resultset('Artist')->find_or_new(
1941 { artist => 'fred' }, { key => 'artists' });
1943 $cd->cd_to_producer->find_or_new({ producer => $producer },
1944 { key => 'primary });
1946 Find an existing record from this resultset, based on its primary
1947 key, or a unique constraint. If none exists, instantiate a new result
1948 object and return it. The object will not be saved into your storage
1949 until you call L<DBIx::Class::Row/insert> on it.
1951 You most likely want this method when looking for existing rows using
1952 a unique constraint that is not the primary key, or looking for
1955 If you want objects to be saved immediately, use L</find_or_create> instead.
1957 B<Note>: C<find_or_new> is probably not what you want when creating a
1958 new row in a table that uses primary keys supplied by the
1959 database. Passing in a primary key column with a value of I<undef>
1960 will cause L</find> to attempt to search for a row with a value of
1967 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1968 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1969 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
1972 return $self->new_result($hash);
1979 =item Arguments: \%vals
1981 =item Return Value: a L<DBIx::Class::Row> $object
1985 Attempt to create a single new row or a row with multiple related rows
1986 in the table represented by the resultset (and related tables). This
1987 will not check for duplicate rows before inserting, use
1988 L</find_or_create> to do that.
1990 To create one row for this resultset, pass a hashref of key/value
1991 pairs representing the columns of the table and the values you wish to
1992 store. If the appropriate relationships are set up, foreign key fields
1993 can also be passed an object representing the foreign row, and the
1994 value will be set to its primary key.
1996 To create related objects, pass a hashref for the value if the related
1997 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1998 and use the name of the relationship as the key. (NOT the name of the field,
1999 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
2000 of hashrefs containing the data for each of the rows to create in the foreign
2001 tables, again using the relationship name as the key.
2003 Instead of hashrefs of plain related data (key/value pairs), you may
2004 also pass new or inserted objects. New objects (not inserted yet, see
2005 L</new>), will be inserted into their appropriate tables.
2007 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
2009 Example of creating a new row.
2011 $person_rs->create({
2012 name=>"Some Person",
2013 email=>"somebody@someplace.com"
2016 Example of creating a new row and also creating rows in a related C<has_many>
2017 or C<has_one> resultset. Note Arrayref.
2020 { artistid => 4, name => 'Manufactured Crap', cds => [
2021 { title => 'My First CD', year => 2006 },
2022 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2027 Example of creating a new row and also creating a row in a related
2028 C<belongs_to>resultset. Note Hashref.
2031 title=>"Music for Silly Walks",
2034 name=>"Silly Musician",
2041 my ($self, $attrs) = @_;
2042 $self->throw_exception( "create needs a hashref" )
2043 unless ref $attrs eq 'HASH';
2044 return $self->new_result($attrs)->insert;
2047 =head2 find_or_create
2051 =item Arguments: \%vals, \%attrs?
2053 =item Return Value: $rowobject
2057 $cd->cd_to_producer->find_or_create({ producer => $producer },
2058 { key => 'primary });
2060 Tries to find a record based on its primary key or unique constraints; if none
2061 is found, creates one and returns that instead.
2063 my $cd = $schema->resultset('CD')->find_or_create({
2065 artist => 'Massive Attack',
2066 title => 'Mezzanine',
2070 Also takes an optional C<key> attribute, to search by a specific key or unique
2071 constraint. For example:
2073 my $cd = $schema->resultset('CD')->find_or_create(
2075 artist => 'Massive Attack',
2076 title => 'Mezzanine',
2078 { key => 'cd_artist_title' }
2081 B<Note>: Because find_or_create() reads from the database and then
2082 possibly inserts based on the result, this method is subject to a race
2083 condition. Another process could create a record in the table after
2084 the find has completed and before the create has started. To avoid
2085 this problem, use find_or_create() inside a transaction.
2087 B<Note>: C<find_or_create> is probably not what you want when creating
2088 a new row in a table that uses primary keys supplied by the
2089 database. Passing in a primary key column with a value of I<undef>
2090 will cause L</find> to attempt to search for a row with a value of
2093 See also L</find> and L</update_or_create>. For information on how to declare
2094 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2098 sub find_or_create {
2100 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2101 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2102 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2105 return $self->create($hash);
2108 =head2 update_or_create
2112 =item Arguments: \%col_values, { key => $unique_constraint }?
2114 =item Return Value: $rowobject
2118 $resultset->update_or_create({ col => $val, ... });
2120 First, searches for an existing row matching one of the unique constraints
2121 (including the primary key) on the source of this resultset. If a row is
2122 found, updates it with the other given column values. Otherwise, creates a new
2125 Takes an optional C<key> attribute to search on a specific unique constraint.
2128 # In your application
2129 my $cd = $schema->resultset('CD')->update_or_create(
2131 artist => 'Massive Attack',
2132 title => 'Mezzanine',
2135 { key => 'cd_artist_title' }
2138 $cd->cd_to_producer->update_or_create({
2139 producer => $producer,
2146 If no C<key> is specified, it searches on all unique constraints defined on the
2147 source, including the primary key.
2149 If the C<key> is specified as C<primary>, it searches only on the primary key.
2151 See also L</find> and L</find_or_create>. For information on how to declare
2152 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2154 B<Note>: C<update_or_create> is probably not what you want when
2155 looking for a row in a table that uses primary keys supplied by the
2156 database, unless you actually have a key value. Passing in a primary
2157 key column with a value of I<undef> will cause L</find> to attempt to
2158 search for a row with a value of I<NULL>.
2162 sub update_or_create {
2164 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2165 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2167 my $row = $self->find($cond, $attrs);
2169 $row->update($cond);
2173 return $self->create($cond);
2176 =head2 update_or_new
2180 =item Arguments: \%col_values, { key => $unique_constraint }?
2182 =item Return Value: $rowobject
2186 $resultset->update_or_new({ col => $val, ... });
2188 First, searches for an existing row matching one of the unique constraints
2189 (including the primary key) on the source of this resultset. If a row is
2190 found, updates it with the other given column values. Otherwise, instantiate
2191 a new result object and return it. The object will not be saved into your storage
2192 until you call L<DBIx::Class::Row/insert> on it.
2194 Takes an optional C<key> attribute to search on a specific unique constraint.
2197 # In your application
2198 my $cd = $schema->resultset('CD')->update_or_new(
2200 artist => 'Massive Attack',
2201 title => 'Mezzanine',
2204 { key => 'cd_artist_title' }
2207 if ($cd->in_storage) {
2208 # the cd was updated
2211 # the cd is not yet in the database, let's insert it
2215 See also L</find>, L</find_or_create> and L<find_or_new>.
2221 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2222 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2224 my $row = $self->find( $cond, $attrs );
2225 if ( defined $row ) {
2226 $row->update($cond);
2230 return $self->new_result($cond);
2237 =item Arguments: none
2239 =item Return Value: \@cache_objects?
2243 Gets the contents of the cache for the resultset, if the cache is set.
2245 The cache is populated either by using the L</prefetch> attribute to
2246 L</search> or by calling L</set_cache>.
2258 =item Arguments: \@cache_objects
2260 =item Return Value: \@cache_objects
2264 Sets the contents of the cache for the resultset. Expects an arrayref
2265 of objects of the same class as those produced by the resultset. Note that
2266 if the cache is set the resultset will return the cached objects rather
2267 than re-querying the database even if the cache attr is not set.
2269 The contents of the cache can also be populated by using the
2270 L</prefetch> attribute to L</search>.
2275 my ( $self, $data ) = @_;
2276 $self->throw_exception("set_cache requires an arrayref")
2277 if defined($data) && (ref $data ne 'ARRAY');
2278 $self->{all_cache} = $data;
2285 =item Arguments: none
2287 =item Return Value: []
2291 Clears the cache for the resultset.
2296 shift->set_cache(undef);
2299 =head2 related_resultset
2303 =item Arguments: $relationship_name
2305 =item Return Value: $resultset
2309 Returns a related resultset for the supplied relationship name.
2311 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2315 sub related_resultset {
2316 my ($self, $rel) = @_;
2318 $self->{related_resultsets} ||= {};
2319 return $self->{related_resultsets}{$rel} ||= do {
2320 my $rel_obj = $self->result_source->relationship_info($rel);
2322 $self->throw_exception(
2323 "search_related: result source '" . $self->result_source->source_name .
2324 "' has no such relationship $rel")
2327 my ($from,$seen) = $self->_resolve_from($rel);
2329 my $join_count = $seen->{$rel};
2330 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2332 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2333 my %attrs = %{$self->{attrs}||{}};
2334 delete @attrs{qw(result_class alias)};
2338 if (my $cache = $self->get_cache) {
2339 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2340 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2345 my $rel_source = $self->result_source->related_source($rel);
2349 # The reason we do this now instead of passing the alias to the
2350 # search_rs below is that if you wrap/overload resultset on the
2351 # source you need to know what alias it's -going- to have for things
2352 # to work sanely (e.g. RestrictWithObject wants to be able to add
2353 # extra query restrictions, and these may need to be $alias.)
2355 my $attrs = $rel_source->resultset_attributes;
2356 local $attrs->{alias} = $alias;
2358 $rel_source->resultset
2366 where => $self->{cond},
2371 $new->set_cache($new_cache) if $new_cache;
2376 =head2 current_source_alias
2380 =item Arguments: none
2382 =item Return Value: $source_alias
2386 Returns the current table alias for the result source this resultset is built
2387 on, that will be used in the SQL query. Usually it is C<me>.
2389 Currently the source alias that refers to the result set returned by a
2390 L</search>/L</find> family method depends on how you got to the resultset: it's
2391 C<me> by default, but eg. L</search_related> aliases it to the related result
2392 source name (and keeps C<me> referring to the original result set). The long
2393 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2394 (and make this method unnecessary).
2396 Thus it's currently necessary to use this method in predefined queries (see
2397 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2398 source alias of the current result set:
2400 # in a result set class
2402 my ($self, $user) = @_;
2404 my $me = $self->current_source_alias;
2406 return $self->search(
2407 "$me.modified" => $user->id,
2413 sub current_source_alias {
2416 return ($self->{attrs} || {})->{alias} || 'me';
2419 # This code is called by search_related, and makes sure there
2420 # is clear separation between the joins before, during, and
2421 # after the relationship. This information is needed later
2422 # in order to properly resolve prefetch aliases (any alias
2423 # with a relation_chain_depth less than the depth of the
2424 # current prefetch is not considered)
2426 my ($self, $extra_join) = @_;
2427 my $source = $self->result_source;
2428 my $attrs = $self->{attrs};
2430 my $from = $attrs->{from}
2431 || [ { $attrs->{alias} => $source->from } ];
2433 my $seen = { %{$attrs->{seen_join} || {} } };
2435 # we need to take the prefetch the attrs into account before we
2436 # ->_resolve_join as otherwise they get lost - captainL
2437 my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
2439 push @$from, $source->_resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
2441 ++$seen->{-relation_chain_depth};
2443 push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
2445 ++$seen->{-relation_chain_depth};
2447 return ($from,$seen);
2450 # too many times we have to do $attrs = { %{$self->_resolved_attrs} }
2451 sub _resolved_attrs_copy {
2453 return { %{$self->_resolved_attrs (@_)} };
2456 sub _resolved_attrs {
2458 return $self->{_attrs} if $self->{_attrs};
2460 my $attrs = { %{ $self->{attrs} || {} } };
2461 my $source = $self->result_source;
2462 my $alias = $attrs->{alias};
2464 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2467 # build columns (as long as select isn't set) into a set of as/select hashes
2468 unless ( $attrs->{select} ) {
2470 ( ref($_) eq 'HASH' )
2474 /^\Q${alias}.\E(.+)$/
2485 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2487 # add the additional columns on
2488 foreach ( 'include_columns', '+columns' ) {
2489 push @colbits, map {
2490 ( ref($_) eq 'HASH' )
2492 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2493 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2496 # start with initial select items
2497 if ( $attrs->{select} ) {
2499 ( ref $attrs->{select} eq 'ARRAY' )
2500 ? [ @{ $attrs->{select} } ]
2501 : [ $attrs->{select} ];
2505 ref $attrs->{as} eq 'ARRAY'
2506 ? [ @{ $attrs->{as} } ]
2509 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2514 # otherwise we intialise select & as to empty
2515 $attrs->{select} = [];
2519 # now add colbits to select/as
2520 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2521 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2524 if ( $adds = delete $attrs->{'+select'} ) {
2525 $adds = [$adds] unless ref $adds eq 'ARRAY';
2527 @{ $attrs->{select} },
2528 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2531 if ( $adds = delete $attrs->{'+as'} ) {
2532 $adds = [$adds] unless ref $adds eq 'ARRAY';
2533 push( @{ $attrs->{as} }, @$adds );
2536 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2538 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2539 my $join = delete $attrs->{join} || {};
2541 if ( defined $attrs->{prefetch} ) {
2542 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2546 $attrs->{from} = # have to copy here to avoid corrupting the original
2548 @{ $attrs->{from} },
2549 $source->_resolve_join(
2550 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2556 if ( $attrs->{order_by} ) {
2557 $attrs->{order_by} = (
2558 ref( $attrs->{order_by} ) eq 'ARRAY'
2559 ? [ @{ $attrs->{order_by} } ]
2560 : [ $attrs->{order_by} ]
2564 $attrs->{order_by} = [];
2567 # If the order_by is otherwise empty - we will use this for TOP limit
2568 # emulation and the like.
2569 # Although this is needed only if the order_by is not defined, it is
2570 # actually cheaper to just populate this rather than properly examining
2571 # order_by (stuf like [ {} ] and the like)
2572 $attrs->{_virtual_order_by} = [ $self->result_source->primary_columns ];
2575 my $collapse = $attrs->{collapse} || {};
2576 if ( my $prefetch = delete $attrs->{prefetch} ) {
2577 $prefetch = $self->_merge_attr( {}, $prefetch );
2579 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2581 # bring joins back to level of current class
2582 my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
2584 $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
2585 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2586 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2588 push( @{ $attrs->{order_by} }, @pre_order );
2591 if (delete $attrs->{distinct}) {
2592 $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
2595 $attrs->{collapse} = $collapse;
2597 if ( $attrs->{page} and not defined $attrs->{offset} ) {
2598 $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2601 return $self->{_attrs} = $attrs;
2604 sub _joinpath_aliases {
2605 my ($self, $fromspec, $seen) = @_;
2608 return $paths unless ref $fromspec eq 'ARRAY';
2610 for my $j (@$fromspec) {
2612 next if ref $j ne 'ARRAY';
2613 next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
2616 $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
2617 push @{$p->{-join_aliases} }, $j->[0]{-join_alias};
2624 my ($self, $attr) = @_;
2626 if (ref $attr eq 'HASH') {
2627 return $self->_rollout_hash($attr);
2628 } elsif (ref $attr eq 'ARRAY') {
2629 return $self->_rollout_array($attr);
2635 sub _rollout_array {
2636 my ($self, $attr) = @_;
2639 foreach my $element (@{$attr}) {
2640 if (ref $element eq 'HASH') {
2641 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2642 } elsif (ref $element eq 'ARRAY') {
2643 # XXX - should probably recurse here
2644 push( @rolled_array, @{$self->_rollout_array($element)} );
2646 push( @rolled_array, $element );
2649 return \@rolled_array;
2653 my ($self, $attr) = @_;
2656 foreach my $key (keys %{$attr}) {
2657 push( @rolled_array, { $key => $attr->{$key} } );
2659 return \@rolled_array;
2662 sub _calculate_score {
2663 my ($self, $a, $b) = @_;
2665 if (ref $b eq 'HASH') {
2666 my ($b_key) = keys %{$b};
2667 if (ref $a eq 'HASH') {
2668 my ($a_key) = keys %{$a};
2669 if ($a_key eq $b_key) {
2670 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2675 return ($a eq $b_key) ? 1 : 0;
2678 if (ref $a eq 'HASH') {
2679 my ($a_key) = keys %{$a};
2680 return ($b eq $a_key) ? 1 : 0;
2682 return ($b eq $a) ? 1 : 0;
2688 my ($self, $orig, $import) = @_;
2690 return $import unless defined($orig);
2691 return $orig unless defined($import);
2693 $orig = $self->_rollout_attr($orig);
2694 $import = $self->_rollout_attr($import);
2697 foreach my $import_element ( @{$import} ) {
2698 # find best candidate from $orig to merge $b_element into
2699 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2700 foreach my $orig_element ( @{$orig} ) {
2701 my $score = $self->_calculate_score( $orig_element, $import_element );
2702 if ($score > $best_candidate->{score}) {
2703 $best_candidate->{position} = $position;
2704 $best_candidate->{score} = $score;
2708 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2710 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2711 push( @{$orig}, $import_element );
2713 my $orig_best = $orig->[$best_candidate->{position}];
2714 # merge orig_best and b_element together and replace original with merged
2715 if (ref $orig_best ne 'HASH') {
2716 $orig->[$best_candidate->{position}] = $import_element;
2717 } elsif (ref $import_element eq 'HASH') {
2718 my ($key) = keys %{$orig_best};
2719 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2722 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2732 $self->_source_handle($_[0]->handle);
2734 $self->_source_handle->resolve;
2738 =head2 throw_exception
2740 See L<DBIx::Class::Schema/throw_exception> for details.
2744 sub throw_exception {
2746 if (ref $self && $self->_source_handle->schema) {
2747 $self->_source_handle->schema->throw_exception(@_)
2754 # XXX: FIXME: Attributes docs need clearing up
2758 Attributes are used to refine a ResultSet in various ways when
2759 searching for data. They can be passed to any method which takes an
2760 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2763 These are in no particular order:
2769 =item Value: ( $order_by | \@order_by | \%order_by )
2773 Which column(s) to order the results by. If a single column name, or
2774 an arrayref of names is supplied, the argument is passed through
2775 directly to SQL. The hashref syntax allows for connection-agnostic
2776 specification of ordering direction:
2778 For descending order:
2780 order_by => { -desc => [qw/col1 col2 col3/] }
2782 For explicit ascending order:
2784 order_by => { -asc => 'col' }
2786 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2787 supported, although you are strongly encouraged to use the hashref
2788 syntax as outlined above.
2794 =item Value: \@columns
2798 Shortcut to request a particular set of columns to be retrieved. Each
2799 column spec may be a string (a table column name), or a hash (in which
2800 case the key is the C<as> value, and the value is used as the C<select>
2801 expression). Adds C<me.> onto the start of any column without a C<.> in
2802 it and sets C<select> from that, then auto-populates C<as> from
2803 C<select> as normal. (You may also use the C<cols> attribute, as in
2804 earlier versions of DBIC.)
2810 =item Value: \@columns
2814 Indicates additional columns to be selected from storage. Works the same
2815 as L</columns> but adds columns to the selection. (You may also use the
2816 C<include_columns> attribute, as in earlier versions of DBIC). For
2819 $schema->resultset('CD')->search(undef, {
2820 '+columns' => ['artist.name'],
2824 would return all CDs and include a 'name' column to the information
2825 passed to object inflation. Note that the 'artist' is the name of the
2826 column (or relationship) accessor, and 'name' is the name of the column
2827 accessor in the related table.
2829 =head2 include_columns
2833 =item Value: \@columns
2837 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2843 =item Value: \@select_columns
2847 Indicates which columns should be selected from the storage. You can use
2848 column names, or in the case of RDBMS back ends, function or stored procedure
2851 $rs = $schema->resultset('Employee')->search(undef, {
2854 { count => 'employeeid' },
2859 When you use function/stored procedure names and do not supply an C<as>
2860 attribute, the column names returned are storage-dependent. E.g. MySQL would
2861 return a column named C<count(employeeid)> in the above example.
2867 Indicates additional columns to be selected from storage. Works the same as
2868 L</select> but adds columns to the selection.
2876 Indicates additional column names for those added via L</+select>. See L</as>.
2884 =item Value: \@inflation_names
2888 Indicates column names for object inflation. That is, C<as>
2889 indicates the name that the column can be accessed as via the
2890 C<get_column> method (or via the object accessor, B<if one already
2891 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2893 The C<as> attribute is used in conjunction with C<select>,
2894 usually when C<select> contains one or more function or stored
2897 $rs = $schema->resultset('Employee')->search(undef, {
2900 { count => 'employeeid' }
2902 as => ['name', 'employee_count'],
2905 my $employee = $rs->first(); # get the first Employee
2907 If the object against which the search is performed already has an accessor
2908 matching a column name specified in C<as>, the value can be retrieved using
2909 the accessor as normal:
2911 my $name = $employee->name();
2913 If on the other hand an accessor does not exist in the object, you need to
2914 use C<get_column> instead:
2916 my $employee_count = $employee->get_column('employee_count');
2918 You can create your own accessors if required - see
2919 L<DBIx::Class::Manual::Cookbook> for details.
2921 Please note: This will NOT insert an C<AS employee_count> into the SQL
2922 statement produced, it is used for internal access only. Thus
2923 attempting to use the accessor in an C<order_by> clause or similar
2924 will fail miserably.
2926 To get around this limitation, you can supply literal SQL to your
2927 C<select> attibute that contains the C<AS alias> text, eg:
2929 select => [\'myfield AS alias']
2935 =item Value: ($rel_name | \@rel_names | \%rel_names)
2939 Contains a list of relationships that should be joined for this query. For
2942 # Get CDs by Nine Inch Nails
2943 my $rs = $schema->resultset('CD')->search(
2944 { 'artist.name' => 'Nine Inch Nails' },
2945 { join => 'artist' }
2948 Can also contain a hash reference to refer to the other relation's relations.
2951 package MyApp::Schema::Track;
2952 use base qw/DBIx::Class/;
2953 __PACKAGE__->table('track');
2954 __PACKAGE__->add_columns(qw/trackid cd position title/);
2955 __PACKAGE__->set_primary_key('trackid');
2956 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2959 # In your application
2960 my $rs = $schema->resultset('Artist')->search(
2961 { 'track.title' => 'Teardrop' },
2963 join => { cd => 'track' },
2964 order_by => 'artist.name',
2968 You need to use the relationship (not the table) name in conditions,
2969 because they are aliased as such. The current table is aliased as "me", so
2970 you need to use me.column_name in order to avoid ambiguity. For example:
2972 # Get CDs from 1984 with a 'Foo' track
2973 my $rs = $schema->resultset('CD')->search(
2976 'tracks.name' => 'Foo'
2978 { join => 'tracks' }
2981 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2982 similarly for a third time). For e.g.
2984 my $rs = $schema->resultset('Artist')->search({
2985 'cds.title' => 'Down to Earth',
2986 'cds_2.title' => 'Popular',
2988 join => [ qw/cds cds/ ],
2991 will return a set of all artists that have both a cd with title 'Down
2992 to Earth' and a cd with title 'Popular'.
2994 If you want to fetch related objects from other tables as well, see C<prefetch>
2997 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
3003 =item Value: ($rel_name | \@rel_names | \%rel_names)
3007 Contains one or more relationships that should be fetched along with
3008 the main query (when they are accessed afterwards the data will
3009 already be available, without extra queries to the database). This is
3010 useful for when you know you will need the related objects, because it
3011 saves at least one query:
3013 my $rs = $schema->resultset('Tag')->search(
3022 The initial search results in SQL like the following:
3024 SELECT tag.*, cd.*, artist.* FROM tag
3025 JOIN cd ON tag.cd = cd.cdid
3026 JOIN artist ON cd.artist = artist.artistid
3028 L<DBIx::Class> has no need to go back to the database when we access the
3029 C<cd> or C<artist> relationships, which saves us two SQL statements in this
3032 Simple prefetches will be joined automatically, so there is no need
3033 for a C<join> attribute in the above search.
3035 C<prefetch> can be used with the following relationship types: C<belongs_to>,
3036 C<has_one> (or if you're using C<add_relationship>, any relationship declared
3037 with an accessor type of 'single' or 'filter'). A more complex example that
3038 prefetches an artists cds, the tracks on those cds, and the tags associted
3039 with that artist is given below (assuming many-to-many from artists to tags):
3041 my $rs = $schema->resultset('Artist')->search(
3045 { cds => 'tracks' },
3046 { artist_tags => 'tags' }
3052 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
3053 attributes will be ignored.
3063 Makes the resultset paged and specifies the page to retrieve. Effectively
3064 identical to creating a non-pages resultset and then calling ->page($page)
3067 If L<rows> attribute is not specified it defualts to 10 rows per page.
3069 When you have a paged resultset, L</count> will only return the number
3070 of rows in the page. To get the total, use the L</pager> and call
3071 C<total_entries> on it.
3081 Specifes the maximum number of rows for direct retrieval or the number of
3082 rows per page if the page attribute or method is used.
3088 =item Value: $offset
3092 Specifies the (zero-based) row number for the first row to be returned, or the
3093 of the first row of the first page if paging is used.
3099 =item Value: \@columns
3103 A arrayref of columns to group by. Can include columns of joined tables.
3105 group_by => [qw/ column1 column2 ... /]
3111 =item Value: $condition
3115 HAVING is a select statement attribute that is applied between GROUP BY and
3116 ORDER BY. It is applied to the after the grouping calculations have been
3119 having => { 'count(employee)' => { '>=', 100 } }
3125 =item Value: (0 | 1)
3129 Set to 1 to group by all columns.
3135 Adds to the WHERE clause.
3137 # only return rows WHERE deleted IS NULL for all searches
3138 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3140 Can be overridden by passing C<{ where => undef }> as an attribute
3147 Set to 1 to cache search results. This prevents extra SQL queries if you
3148 revisit rows in your ResultSet:
3150 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3152 while( my $artist = $resultset->next ) {
3156 $rs->first; # without cache, this would issue a query
3158 By default, searches are not cached.
3160 For more examples of using these attributes, see
3161 L<DBIx::Class::Manual::Cookbook>.
3167 =item Value: \@from_clause
3171 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3172 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3175 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3177 C<join> will usually do what you need and it is strongly recommended that you
3178 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3179 And we really do mean "cannot", not just tried and failed. Attempting to use
3180 this because you're having problems with C<join> is like trying to use x86
3181 ASM because you've got a syntax error in your C. Trust us on this.
3183 Now, if you're still really, really sure you need to use this (and if you're
3184 not 100% sure, ask the mailing list first), here's an explanation of how this
3187 The syntax is as follows -
3190 { <alias1> => <table1> },
3192 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3193 [], # nested JOIN (optional)
3194 { <table1.column1> => <table2.column2>, ... (more conditions) },
3196 # More of the above [ ] may follow for additional joins
3203 ON <table1.column1> = <table2.column2>
3204 <more joins may follow>
3206 An easy way to follow the examples below is to remember the following:
3208 Anything inside "[]" is a JOIN
3209 Anything inside "{}" is a condition for the enclosing JOIN
3211 The following examples utilize a "person" table in a family tree application.
3212 In order to express parent->child relationships, this table is self-joined:
3214 # Person->belongs_to('father' => 'Person');
3215 # Person->belongs_to('mother' => 'Person');
3217 C<from> can be used to nest joins. Here we return all children with a father,
3218 then search against all mothers of those children:
3220 $rs = $schema->resultset('Person')->search(
3223 alias => 'mother', # alias columns in accordance with "from"
3225 { mother => 'person' },
3228 { child => 'person' },
3230 { father => 'person' },
3231 { 'father.person_id' => 'child.father_id' }
3234 { 'mother.person_id' => 'child.mother_id' }
3241 # SELECT mother.* FROM person mother
3244 # JOIN person father
3245 # ON ( father.person_id = child.father_id )
3247 # ON ( mother.person_id = child.mother_id )
3249 The type of any join can be controlled manually. To search against only people
3250 with a father in the person table, we could explicitly use C<INNER JOIN>:
3252 $rs = $schema->resultset('Person')->search(
3255 alias => 'child', # alias columns in accordance with "from"
3257 { child => 'person' },
3259 { father => 'person', -join_type => 'inner' },
3260 { 'father.id' => 'child.father_id' }
3267 # SELECT child.* FROM person child
3268 # INNER JOIN person father ON child.father_id = father.id
3270 If you need to express really complex joins or you need a subselect, you
3271 can supply literal SQL to C<from> via a scalar reference. In this case
3272 the contents of the scalar will replace the table name asscoiated with the
3275 WARNING: This technique might very well not work as expected on chained
3276 searches - you have been warned.
3278 # Assuming the Event resultsource is defined as:
3280 MySchema::Event->add_columns (
3283 is_auto_increment => 1,
3292 MySchema::Event->set_primary_key ('sequence');
3294 # This will get back the latest event for every location. The column
3295 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3296 # combo to limit the resultset
3298 $rs = $schema->resultset('Event');
3299 $table = $rs->result_source->name;
3300 $latest = $rs->search (
3303 (SELECT e1.* FROM $table e1
3305 ON e1.location = e2.location
3306 AND e1.sequence < e2.sequence
3307 WHERE e2.sequence is NULL
3312 # Equivalent SQL (with the DBIC chunks added):
3314 SELECT me.sequence, me.location, me.type FROM
3315 (SELECT e1.* FROM events e1
3317 ON e1.location = e2.location
3318 AND e1.sequence < e2.sequence
3319 WHERE e2.sequence is NULL
3326 =item Value: ( 'update' | 'shared' )
3330 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT