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.
1931 my $attrs = $self->_resolved_attrs_copy;
1933 my ($sqlbind, $bind_attrs) = $self->result_source->storage
1934 ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
1943 =item Arguments: \%vals, \%attrs?
1945 =item Return Value: $rowobject
1949 my $artist = $schema->resultset('Artist')->find_or_new(
1950 { artist => 'fred' }, { key => 'artists' });
1952 $cd->cd_to_producer->find_or_new({ producer => $producer },
1953 { key => 'primary });
1955 Find an existing record from this resultset, based on its primary
1956 key, or a unique constraint. If none exists, instantiate a new result
1957 object and return it. The object will not be saved into your storage
1958 until you call L<DBIx::Class::Row/insert> on it.
1960 You most likely want this method when looking for existing rows using
1961 a unique constraint that is not the primary key, or looking for
1964 If you want objects to be saved immediately, use L</find_or_create> instead.
1966 B<Note>: C<find_or_new> is probably not what you want when creating a
1967 new row in a table that uses primary keys supplied by the
1968 database. Passing in a primary key column with a value of I<undef>
1969 will cause L</find> to attempt to search for a row with a value of
1976 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1977 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1978 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
1981 return $self->new_result($hash);
1988 =item Arguments: \%vals
1990 =item Return Value: a L<DBIx::Class::Row> $object
1994 Attempt to create a single new row or a row with multiple related rows
1995 in the table represented by the resultset (and related tables). This
1996 will not check for duplicate rows before inserting, use
1997 L</find_or_create> to do that.
1999 To create one row for this resultset, pass a hashref of key/value
2000 pairs representing the columns of the table and the values you wish to
2001 store. If the appropriate relationships are set up, foreign key fields
2002 can also be passed an object representing the foreign row, and the
2003 value will be set to its primary key.
2005 To create related objects, pass a hashref for the value if the related
2006 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
2007 and use the name of the relationship as the key. (NOT the name of the field,
2008 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
2009 of hashrefs containing the data for each of the rows to create in the foreign
2010 tables, again using the relationship name as the key.
2012 Instead of hashrefs of plain related data (key/value pairs), you may
2013 also pass new or inserted objects. New objects (not inserted yet, see
2014 L</new>), will be inserted into their appropriate tables.
2016 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
2018 Example of creating a new row.
2020 $person_rs->create({
2021 name=>"Some Person",
2022 email=>"somebody@someplace.com"
2025 Example of creating a new row and also creating rows in a related C<has_many>
2026 or C<has_one> resultset. Note Arrayref.
2029 { artistid => 4, name => 'Manufactured Crap', cds => [
2030 { title => 'My First CD', year => 2006 },
2031 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2036 Example of creating a new row and also creating a row in a related
2037 C<belongs_to>resultset. Note Hashref.
2040 title=>"Music for Silly Walks",
2043 name=>"Silly Musician",
2050 my ($self, $attrs) = @_;
2051 $self->throw_exception( "create needs a hashref" )
2052 unless ref $attrs eq 'HASH';
2053 return $self->new_result($attrs)->insert;
2056 =head2 find_or_create
2060 =item Arguments: \%vals, \%attrs?
2062 =item Return Value: $rowobject
2066 $cd->cd_to_producer->find_or_create({ producer => $producer },
2067 { key => 'primary });
2069 Tries to find a record based on its primary key or unique constraints; if none
2070 is found, creates one and returns that instead.
2072 my $cd = $schema->resultset('CD')->find_or_create({
2074 artist => 'Massive Attack',
2075 title => 'Mezzanine',
2079 Also takes an optional C<key> attribute, to search by a specific key or unique
2080 constraint. For example:
2082 my $cd = $schema->resultset('CD')->find_or_create(
2084 artist => 'Massive Attack',
2085 title => 'Mezzanine',
2087 { key => 'cd_artist_title' }
2090 B<Note>: Because find_or_create() reads from the database and then
2091 possibly inserts based on the result, this method is subject to a race
2092 condition. Another process could create a record in the table after
2093 the find has completed and before the create has started. To avoid
2094 this problem, use find_or_create() inside a transaction.
2096 B<Note>: C<find_or_create> is probably not what you want when creating
2097 a new row in a table that uses primary keys supplied by the
2098 database. Passing in a primary key column with a value of I<undef>
2099 will cause L</find> to attempt to search for a row with a value of
2102 See also L</find> and L</update_or_create>. For information on how to declare
2103 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2107 sub find_or_create {
2109 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2110 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2111 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2114 return $self->create($hash);
2117 =head2 update_or_create
2121 =item Arguments: \%col_values, { key => $unique_constraint }?
2123 =item Return Value: $rowobject
2127 $resultset->update_or_create({ col => $val, ... });
2129 First, searches for an existing row matching one of the unique constraints
2130 (including the primary key) on the source of this resultset. If a row is
2131 found, updates it with the other given column values. Otherwise, creates a new
2134 Takes an optional C<key> attribute to search on a specific unique constraint.
2137 # In your application
2138 my $cd = $schema->resultset('CD')->update_or_create(
2140 artist => 'Massive Attack',
2141 title => 'Mezzanine',
2144 { key => 'cd_artist_title' }
2147 $cd->cd_to_producer->update_or_create({
2148 producer => $producer,
2155 If no C<key> is specified, it searches on all unique constraints defined on the
2156 source, including the primary key.
2158 If the C<key> is specified as C<primary>, it searches only on the primary key.
2160 See also L</find> and L</find_or_create>. For information on how to declare
2161 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2163 B<Note>: C<update_or_create> is probably not what you want when
2164 looking for a row in a table that uses primary keys supplied by the
2165 database, unless you actually have a key value. Passing in a primary
2166 key column with a value of I<undef> will cause L</find> to attempt to
2167 search for a row with a value of I<NULL>.
2171 sub update_or_create {
2173 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2174 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2176 my $row = $self->find($cond, $attrs);
2178 $row->update($cond);
2182 return $self->create($cond);
2185 =head2 update_or_new
2189 =item Arguments: \%col_values, { key => $unique_constraint }?
2191 =item Return Value: $rowobject
2195 $resultset->update_or_new({ col => $val, ... });
2197 First, searches for an existing row matching one of the unique constraints
2198 (including the primary key) on the source of this resultset. If a row is
2199 found, updates it with the other given column values. Otherwise, instantiate
2200 a new result object and return it. The object will not be saved into your storage
2201 until you call L<DBIx::Class::Row/insert> on it.
2203 Takes an optional C<key> attribute to search on a specific unique constraint.
2206 # In your application
2207 my $cd = $schema->resultset('CD')->update_or_new(
2209 artist => 'Massive Attack',
2210 title => 'Mezzanine',
2213 { key => 'cd_artist_title' }
2216 if ($cd->in_storage) {
2217 # the cd was updated
2220 # the cd is not yet in the database, let's insert it
2224 See also L</find>, L</find_or_create> and L<find_or_new>.
2230 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2231 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2233 my $row = $self->find( $cond, $attrs );
2234 if ( defined $row ) {
2235 $row->update($cond);
2239 return $self->new_result($cond);
2246 =item Arguments: none
2248 =item Return Value: \@cache_objects?
2252 Gets the contents of the cache for the resultset, if the cache is set.
2254 The cache is populated either by using the L</prefetch> attribute to
2255 L</search> or by calling L</set_cache>.
2267 =item Arguments: \@cache_objects
2269 =item Return Value: \@cache_objects
2273 Sets the contents of the cache for the resultset. Expects an arrayref
2274 of objects of the same class as those produced by the resultset. Note that
2275 if the cache is set the resultset will return the cached objects rather
2276 than re-querying the database even if the cache attr is not set.
2278 The contents of the cache can also be populated by using the
2279 L</prefetch> attribute to L</search>.
2284 my ( $self, $data ) = @_;
2285 $self->throw_exception("set_cache requires an arrayref")
2286 if defined($data) && (ref $data ne 'ARRAY');
2287 $self->{all_cache} = $data;
2294 =item Arguments: none
2296 =item Return Value: []
2300 Clears the cache for the resultset.
2305 shift->set_cache(undef);
2308 =head2 related_resultset
2312 =item Arguments: $relationship_name
2314 =item Return Value: $resultset
2318 Returns a related resultset for the supplied relationship name.
2320 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2324 sub related_resultset {
2325 my ($self, $rel) = @_;
2327 $self->{related_resultsets} ||= {};
2328 return $self->{related_resultsets}{$rel} ||= do {
2329 my $rel_obj = $self->result_source->relationship_info($rel);
2331 $self->throw_exception(
2332 "search_related: result source '" . $self->result_source->source_name .
2333 "' has no such relationship $rel")
2336 my ($from,$seen) = $self->_resolve_from($rel);
2338 my $join_count = $seen->{$rel};
2339 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2341 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2342 my %attrs = %{$self->{attrs}||{}};
2343 delete @attrs{qw(result_class alias)};
2347 if (my $cache = $self->get_cache) {
2348 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2349 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2354 my $rel_source = $self->result_source->related_source($rel);
2358 # The reason we do this now instead of passing the alias to the
2359 # search_rs below is that if you wrap/overload resultset on the
2360 # source you need to know what alias it's -going- to have for things
2361 # to work sanely (e.g. RestrictWithObject wants to be able to add
2362 # extra query restrictions, and these may need to be $alias.)
2364 my $attrs = $rel_source->resultset_attributes;
2365 local $attrs->{alias} = $alias;
2367 $rel_source->resultset
2375 where => $self->{cond},
2380 $new->set_cache($new_cache) if $new_cache;
2385 =head2 current_source_alias
2389 =item Arguments: none
2391 =item Return Value: $source_alias
2395 Returns the current table alias for the result source this resultset is built
2396 on, that will be used in the SQL query. Usually it is C<me>.
2398 Currently the source alias that refers to the result set returned by a
2399 L</search>/L</find> family method depends on how you got to the resultset: it's
2400 C<me> by default, but eg. L</search_related> aliases it to the related result
2401 source name (and keeps C<me> referring to the original result set). The long
2402 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2403 (and make this method unnecessary).
2405 Thus it's currently necessary to use this method in predefined queries (see
2406 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2407 source alias of the current result set:
2409 # in a result set class
2411 my ($self, $user) = @_;
2413 my $me = $self->current_source_alias;
2415 return $self->search(
2416 "$me.modified" => $user->id,
2422 sub current_source_alias {
2425 return ($self->{attrs} || {})->{alias} || 'me';
2428 # This code is called by search_related, and makes sure there
2429 # is clear separation between the joins before, during, and
2430 # after the relationship. This information is needed later
2431 # in order to properly resolve prefetch aliases (any alias
2432 # with a relation_chain_depth less than the depth of the
2433 # current prefetch is not considered)
2435 my ($self, $extra_join) = @_;
2436 my $source = $self->result_source;
2437 my $attrs = $self->{attrs};
2443 -result_source => $source,
2444 -alias => $attrs->{alias},
2445 $attrs->{alias} => $source->from,
2449 my $seen = { %{$attrs->{seen_join} || {} } };
2451 # we need to take the prefetch the attrs into account before we
2452 # ->_resolve_join as otherwise they get lost - captainL
2453 my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
2455 push @$from, $source->_resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
2457 ++$seen->{-relation_chain_depth};
2459 push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
2461 ++$seen->{-relation_chain_depth};
2463 return ($from,$seen);
2466 # too many times we have to do $attrs = { %{$self->_resolved_attrs} }
2467 sub _resolved_attrs_copy {
2469 return { %{$self->_resolved_attrs (@_)} };
2472 sub _resolved_attrs {
2474 return $self->{_attrs} if $self->{_attrs};
2476 my $attrs = { %{ $self->{attrs} || {} } };
2477 my $source = $self->result_source;
2478 my $alias = $attrs->{alias};
2480 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2483 # build columns (as long as select isn't set) into a set of as/select hashes
2484 unless ( $attrs->{select} ) {
2486 ( ref($_) eq 'HASH' )
2490 /^\Q${alias}.\E(.+)$/
2501 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2503 # add the additional columns on
2504 foreach ( 'include_columns', '+columns' ) {
2505 push @colbits, map {
2506 ( ref($_) eq 'HASH' )
2508 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2509 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2512 # start with initial select items
2513 if ( $attrs->{select} ) {
2515 ( ref $attrs->{select} eq 'ARRAY' )
2516 ? [ @{ $attrs->{select} } ]
2517 : [ $attrs->{select} ];
2521 ref $attrs->{as} eq 'ARRAY'
2522 ? [ @{ $attrs->{as} } ]
2525 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2530 # otherwise we intialise select & as to empty
2531 $attrs->{select} = [];
2535 # now add colbits to select/as
2536 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2537 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2540 if ( $adds = delete $attrs->{'+select'} ) {
2541 $adds = [$adds] unless ref $adds eq 'ARRAY';
2543 @{ $attrs->{select} },
2544 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2547 if ( $adds = delete $attrs->{'+as'} ) {
2548 $adds = [$adds] unless ref $adds eq 'ARRAY';
2549 push( @{ $attrs->{as} }, @$adds );
2552 $attrs->{from} ||= [ {
2553 -result_source => $source,
2554 -alias => $self->{attrs}{alias},
2555 $self->{attrs}{alias} => $source->from,
2558 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2559 my $join = delete $attrs->{join} || {};
2561 if ( defined $attrs->{prefetch} ) {
2562 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2566 $attrs->{from} = # have to copy here to avoid corrupting the original
2568 @{ $attrs->{from} },
2569 $source->_resolve_join(
2570 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2576 if ( $attrs->{order_by} ) {
2577 $attrs->{order_by} = (
2578 ref( $attrs->{order_by} ) eq 'ARRAY'
2579 ? [ @{ $attrs->{order_by} } ]
2580 : [ $attrs->{order_by} ]
2584 $attrs->{order_by} = [];
2587 # If the order_by is otherwise empty - we will use this for TOP limit
2588 # emulation and the like.
2589 # Although this is needed only if the order_by is not defined, it is
2590 # actually cheaper to just populate this rather than properly examining
2591 # order_by (stuf like [ {} ] and the like)
2592 $attrs->{_virtual_order_by} = [ $self->result_source->primary_columns ];
2595 my $collapse = $attrs->{collapse} || {};
2596 if ( my $prefetch = delete $attrs->{prefetch} ) {
2597 $prefetch = $self->_merge_attr( {}, $prefetch );
2599 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2601 # bring joins back to level of current class
2602 my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
2604 $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
2605 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2606 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2608 push( @{ $attrs->{order_by} }, @pre_order );
2611 if (delete $attrs->{distinct}) {
2612 $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
2615 $attrs->{collapse} = $collapse;
2617 if ( $attrs->{page} and not defined $attrs->{offset} ) {
2618 $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2621 return $self->{_attrs} = $attrs;
2624 sub _joinpath_aliases {
2625 my ($self, $fromspec, $seen) = @_;
2628 return $paths unless ref $fromspec eq 'ARRAY';
2630 for my $j (@$fromspec) {
2632 next if ref $j ne 'ARRAY';
2633 next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
2636 $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
2637 push @{$p->{-join_aliases} }, $j->[0]{-alias};
2644 my ($self, $attr) = @_;
2646 if (ref $attr eq 'HASH') {
2647 return $self->_rollout_hash($attr);
2648 } elsif (ref $attr eq 'ARRAY') {
2649 return $self->_rollout_array($attr);
2655 sub _rollout_array {
2656 my ($self, $attr) = @_;
2659 foreach my $element (@{$attr}) {
2660 if (ref $element eq 'HASH') {
2661 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2662 } elsif (ref $element eq 'ARRAY') {
2663 # XXX - should probably recurse here
2664 push( @rolled_array, @{$self->_rollout_array($element)} );
2666 push( @rolled_array, $element );
2669 return \@rolled_array;
2673 my ($self, $attr) = @_;
2676 foreach my $key (keys %{$attr}) {
2677 push( @rolled_array, { $key => $attr->{$key} } );
2679 return \@rolled_array;
2682 sub _calculate_score {
2683 my ($self, $a, $b) = @_;
2685 if (ref $b eq 'HASH') {
2686 my ($b_key) = keys %{$b};
2687 if (ref $a eq 'HASH') {
2688 my ($a_key) = keys %{$a};
2689 if ($a_key eq $b_key) {
2690 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2695 return ($a eq $b_key) ? 1 : 0;
2698 if (ref $a eq 'HASH') {
2699 my ($a_key) = keys %{$a};
2700 return ($b eq $a_key) ? 1 : 0;
2702 return ($b eq $a) ? 1 : 0;
2708 my ($self, $orig, $import) = @_;
2710 return $import unless defined($orig);
2711 return $orig unless defined($import);
2713 $orig = $self->_rollout_attr($orig);
2714 $import = $self->_rollout_attr($import);
2717 foreach my $import_element ( @{$import} ) {
2718 # find best candidate from $orig to merge $b_element into
2719 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2720 foreach my $orig_element ( @{$orig} ) {
2721 my $score = $self->_calculate_score( $orig_element, $import_element );
2722 if ($score > $best_candidate->{score}) {
2723 $best_candidate->{position} = $position;
2724 $best_candidate->{score} = $score;
2728 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2730 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2731 push( @{$orig}, $import_element );
2733 my $orig_best = $orig->[$best_candidate->{position}];
2734 # merge orig_best and b_element together and replace original with merged
2735 if (ref $orig_best ne 'HASH') {
2736 $orig->[$best_candidate->{position}] = $import_element;
2737 } elsif (ref $import_element eq 'HASH') {
2738 my ($key) = keys %{$orig_best};
2739 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2742 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2752 $self->_source_handle($_[0]->handle);
2754 $self->_source_handle->resolve;
2758 =head2 throw_exception
2760 See L<DBIx::Class::Schema/throw_exception> for details.
2764 sub throw_exception {
2766 if (ref $self && $self->_source_handle->schema) {
2767 $self->_source_handle->schema->throw_exception(@_)
2774 # XXX: FIXME: Attributes docs need clearing up
2778 Attributes are used to refine a ResultSet in various ways when
2779 searching for data. They can be passed to any method which takes an
2780 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2783 These are in no particular order:
2789 =item Value: ( $order_by | \@order_by | \%order_by )
2793 Which column(s) to order the results by. If a single column name, or
2794 an arrayref of names is supplied, the argument is passed through
2795 directly to SQL. The hashref syntax allows for connection-agnostic
2796 specification of ordering direction:
2798 For descending order:
2800 order_by => { -desc => [qw/col1 col2 col3/] }
2802 For explicit ascending order:
2804 order_by => { -asc => 'col' }
2806 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2807 supported, although you are strongly encouraged to use the hashref
2808 syntax as outlined above.
2814 =item Value: \@columns
2818 Shortcut to request a particular set of columns to be retrieved. Each
2819 column spec may be a string (a table column name), or a hash (in which
2820 case the key is the C<as> value, and the value is used as the C<select>
2821 expression). Adds C<me.> onto the start of any column without a C<.> in
2822 it and sets C<select> from that, then auto-populates C<as> from
2823 C<select> as normal. (You may also use the C<cols> attribute, as in
2824 earlier versions of DBIC.)
2830 =item Value: \@columns
2834 Indicates additional columns to be selected from storage. Works the same
2835 as L</columns> but adds columns to the selection. (You may also use the
2836 C<include_columns> attribute, as in earlier versions of DBIC). For
2839 $schema->resultset('CD')->search(undef, {
2840 '+columns' => ['artist.name'],
2844 would return all CDs and include a 'name' column to the information
2845 passed to object inflation. Note that the 'artist' is the name of the
2846 column (or relationship) accessor, and 'name' is the name of the column
2847 accessor in the related table.
2849 =head2 include_columns
2853 =item Value: \@columns
2857 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2863 =item Value: \@select_columns
2867 Indicates which columns should be selected from the storage. You can use
2868 column names, or in the case of RDBMS back ends, function or stored procedure
2871 $rs = $schema->resultset('Employee')->search(undef, {
2874 { count => 'employeeid' },
2879 When you use function/stored procedure names and do not supply an C<as>
2880 attribute, the column names returned are storage-dependent. E.g. MySQL would
2881 return a column named C<count(employeeid)> in the above example.
2887 Indicates additional columns to be selected from storage. Works the same as
2888 L</select> but adds columns to the selection.
2896 Indicates additional column names for those added via L</+select>. See L</as>.
2904 =item Value: \@inflation_names
2908 Indicates column names for object inflation. That is, C<as>
2909 indicates the name that the column can be accessed as via the
2910 C<get_column> method (or via the object accessor, B<if one already
2911 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2913 The C<as> attribute is used in conjunction with C<select>,
2914 usually when C<select> contains one or more function or stored
2917 $rs = $schema->resultset('Employee')->search(undef, {
2920 { count => 'employeeid' }
2922 as => ['name', 'employee_count'],
2925 my $employee = $rs->first(); # get the first Employee
2927 If the object against which the search is performed already has an accessor
2928 matching a column name specified in C<as>, the value can be retrieved using
2929 the accessor as normal:
2931 my $name = $employee->name();
2933 If on the other hand an accessor does not exist in the object, you need to
2934 use C<get_column> instead:
2936 my $employee_count = $employee->get_column('employee_count');
2938 You can create your own accessors if required - see
2939 L<DBIx::Class::Manual::Cookbook> for details.
2941 Please note: This will NOT insert an C<AS employee_count> into the SQL
2942 statement produced, it is used for internal access only. Thus
2943 attempting to use the accessor in an C<order_by> clause or similar
2944 will fail miserably.
2946 To get around this limitation, you can supply literal SQL to your
2947 C<select> attibute that contains the C<AS alias> text, eg:
2949 select => [\'myfield AS alias']
2955 =item Value: ($rel_name | \@rel_names | \%rel_names)
2959 Contains a list of relationships that should be joined for this query. For
2962 # Get CDs by Nine Inch Nails
2963 my $rs = $schema->resultset('CD')->search(
2964 { 'artist.name' => 'Nine Inch Nails' },
2965 { join => 'artist' }
2968 Can also contain a hash reference to refer to the other relation's relations.
2971 package MyApp::Schema::Track;
2972 use base qw/DBIx::Class/;
2973 __PACKAGE__->table('track');
2974 __PACKAGE__->add_columns(qw/trackid cd position title/);
2975 __PACKAGE__->set_primary_key('trackid');
2976 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2979 # In your application
2980 my $rs = $schema->resultset('Artist')->search(
2981 { 'track.title' => 'Teardrop' },
2983 join => { cd => 'track' },
2984 order_by => 'artist.name',
2988 You need to use the relationship (not the table) name in conditions,
2989 because they are aliased as such. The current table is aliased as "me", so
2990 you need to use me.column_name in order to avoid ambiguity. For example:
2992 # Get CDs from 1984 with a 'Foo' track
2993 my $rs = $schema->resultset('CD')->search(
2996 'tracks.name' => 'Foo'
2998 { join => 'tracks' }
3001 If the same join is supplied twice, it will be aliased to <rel>_2 (and
3002 similarly for a third time). For e.g.
3004 my $rs = $schema->resultset('Artist')->search({
3005 'cds.title' => 'Down to Earth',
3006 'cds_2.title' => 'Popular',
3008 join => [ qw/cds cds/ ],
3011 will return a set of all artists that have both a cd with title 'Down
3012 to Earth' and a cd with title 'Popular'.
3014 If you want to fetch related objects from other tables as well, see C<prefetch>
3017 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
3023 =item Value: ($rel_name | \@rel_names | \%rel_names)
3027 Contains one or more relationships that should be fetched along with
3028 the main query (when they are accessed afterwards the data will
3029 already be available, without extra queries to the database). This is
3030 useful for when you know you will need the related objects, because it
3031 saves at least one query:
3033 my $rs = $schema->resultset('Tag')->search(
3042 The initial search results in SQL like the following:
3044 SELECT tag.*, cd.*, artist.* FROM tag
3045 JOIN cd ON tag.cd = cd.cdid
3046 JOIN artist ON cd.artist = artist.artistid
3048 L<DBIx::Class> has no need to go back to the database when we access the
3049 C<cd> or C<artist> relationships, which saves us two SQL statements in this
3052 Simple prefetches will be joined automatically, so there is no need
3053 for a C<join> attribute in the above search.
3055 C<prefetch> can be used with the following relationship types: C<belongs_to>,
3056 C<has_one> (or if you're using C<add_relationship>, any relationship declared
3057 with an accessor type of 'single' or 'filter'). A more complex example that
3058 prefetches an artists cds, the tracks on those cds, and the tags associted
3059 with that artist is given below (assuming many-to-many from artists to tags):
3061 my $rs = $schema->resultset('Artist')->search(
3065 { cds => 'tracks' },
3066 { artist_tags => 'tags' }
3072 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
3073 attributes will be ignored.
3083 Makes the resultset paged and specifies the page to retrieve. Effectively
3084 identical to creating a non-pages resultset and then calling ->page($page)
3087 If L<rows> attribute is not specified it defualts to 10 rows per page.
3089 When you have a paged resultset, L</count> will only return the number
3090 of rows in the page. To get the total, use the L</pager> and call
3091 C<total_entries> on it.
3101 Specifes the maximum number of rows for direct retrieval or the number of
3102 rows per page if the page attribute or method is used.
3108 =item Value: $offset
3112 Specifies the (zero-based) row number for the first row to be returned, or the
3113 of the first row of the first page if paging is used.
3119 =item Value: \@columns
3123 A arrayref of columns to group by. Can include columns of joined tables.
3125 group_by => [qw/ column1 column2 ... /]
3131 =item Value: $condition
3135 HAVING is a select statement attribute that is applied between GROUP BY and
3136 ORDER BY. It is applied to the after the grouping calculations have been
3139 having => { 'count(employee)' => { '>=', 100 } }
3145 =item Value: (0 | 1)
3149 Set to 1 to group by all columns.
3155 Adds to the WHERE clause.
3157 # only return rows WHERE deleted IS NULL for all searches
3158 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3160 Can be overridden by passing C<{ where => undef }> as an attribute
3167 Set to 1 to cache search results. This prevents extra SQL queries if you
3168 revisit rows in your ResultSet:
3170 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3172 while( my $artist = $resultset->next ) {
3176 $rs->first; # without cache, this would issue a query
3178 By default, searches are not cached.
3180 For more examples of using these attributes, see
3181 L<DBIx::Class::Manual::Cookbook>.
3187 =item Value: \@from_clause
3191 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3192 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3195 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3197 C<join> will usually do what you need and it is strongly recommended that you
3198 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3199 And we really do mean "cannot", not just tried and failed. Attempting to use
3200 this because you're having problems with C<join> is like trying to use x86
3201 ASM because you've got a syntax error in your C. Trust us on this.
3203 Now, if you're still really, really sure you need to use this (and if you're
3204 not 100% sure, ask the mailing list first), here's an explanation of how this
3207 The syntax is as follows -
3210 { <alias1> => <table1> },
3212 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3213 [], # nested JOIN (optional)
3214 { <table1.column1> => <table2.column2>, ... (more conditions) },
3216 # More of the above [ ] may follow for additional joins
3223 ON <table1.column1> = <table2.column2>
3224 <more joins may follow>
3226 An easy way to follow the examples below is to remember the following:
3228 Anything inside "[]" is a JOIN
3229 Anything inside "{}" is a condition for the enclosing JOIN
3231 The following examples utilize a "person" table in a family tree application.
3232 In order to express parent->child relationships, this table is self-joined:
3234 # Person->belongs_to('father' => 'Person');
3235 # Person->belongs_to('mother' => 'Person');
3237 C<from> can be used to nest joins. Here we return all children with a father,
3238 then search against all mothers of those children:
3240 $rs = $schema->resultset('Person')->search(
3243 alias => 'mother', # alias columns in accordance with "from"
3245 { mother => 'person' },
3248 { child => 'person' },
3250 { father => 'person' },
3251 { 'father.person_id' => 'child.father_id' }
3254 { 'mother.person_id' => 'child.mother_id' }
3261 # SELECT mother.* FROM person mother
3264 # JOIN person father
3265 # ON ( father.person_id = child.father_id )
3267 # ON ( mother.person_id = child.mother_id )
3269 The type of any join can be controlled manually. To search against only people
3270 with a father in the person table, we could explicitly use C<INNER JOIN>:
3272 $rs = $schema->resultset('Person')->search(
3275 alias => 'child', # alias columns in accordance with "from"
3277 { child => 'person' },
3279 { father => 'person', -join_type => 'inner' },
3280 { 'father.id' => 'child.father_id' }
3287 # SELECT child.* FROM person child
3288 # INNER JOIN person father ON child.father_id = father.id
3290 If you need to express really complex joins or you need a subselect, you
3291 can supply literal SQL to C<from> via a scalar reference. In this case
3292 the contents of the scalar will replace the table name asscoiated with the
3295 WARNING: This technique might very well not work as expected on chained
3296 searches - you have been warned.
3298 # Assuming the Event resultsource is defined as:
3300 MySchema::Event->add_columns (
3303 is_auto_increment => 1,
3312 MySchema::Event->set_primary_key ('sequence');
3314 # This will get back the latest event for every location. The column
3315 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3316 # combo to limit the resultset
3318 $rs = $schema->resultset('Event');
3319 $table = $rs->result_source->name;
3320 $latest = $rs->search (
3323 (SELECT e1.* FROM $table e1
3325 ON e1.location = e2.location
3326 AND e1.sequence < e2.sequence
3327 WHERE e2.sequence is NULL
3332 # Equivalent SQL (with the DBIC chunks added):
3334 SELECT me.sequence, me.location, me.type FROM
3335 (SELECT e1.* FROM events e1
3337 ON e1.location = e2.location
3338 AND e1.sequence < e2.sequence
3339 WHERE e2.sequence is NULL
3346 =item Value: ( 'update' | 'shared' )
3350 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT