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;
664 $attrs->{_virtual_order_by} = $self->_gen_virtual_order;
666 return $self->{cursor}
667 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
668 $attrs->{where},$attrs);
675 =item Arguments: $cond?
677 =item Return Value: $row_object?
681 my $cd = $schema->resultset('CD')->single({ year => 2001 });
683 Inflates the first result without creating a cursor if the resultset has
684 any records in it; if not returns nothing. Used by L</find> as a lean version of
687 While this method can take an optional search condition (just like L</search>)
688 being a fast-code-path it does not recognize search attributes. If you need to
689 add extra joins or similar, call L</search> and then chain-call L</single> on the
690 L<DBIx::Class::ResultSet> returned.
696 As of 0.08100, this method enforces the assumption that the preceeding
697 query returns only one row. If more than one row is returned, you will receive
700 Query returned more than one row
702 In this case, you should be using L</first> or L</find> instead, or if you really
703 know what you are doing, use the L</rows> attribute to explicitly limit the size
711 my ($self, $where) = @_;
713 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
716 my $attrs = $self->_resolved_attrs_copy;
717 $attrs->{_virtual_order_by} = $self->_gen_virtual_order;
720 if (defined $attrs->{where}) {
723 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
724 $where, delete $attrs->{where} ]
727 $attrs->{where} = $where;
731 # XXX: Disabled since it doesn't infer uniqueness in all cases
732 # unless ($self->_is_unique_query($attrs->{where})) {
733 # carp "Query not guaranteed to return a single row"
734 # . "; please declare your unique constraints or use search instead";
737 my @data = $self->result_source->storage->select_single(
738 $attrs->{from}, $attrs->{select},
739 $attrs->{where}, $attrs
742 return (@data ? ($self->_construct_object(@data))[0] : undef);
747 # This is a horrble hack, but seems like the best we can do at this point
748 # Some limit emulations (Top) require an ordered resultset in order to
749 # function at all. So supply a PK order to be used if necessary
751 sub _gen_virtual_order {
752 return [ shift->result_source->primary_columns ];
757 # Try to determine if the specified query is guaranteed to be unique, based on
758 # the declared unique constraints.
760 sub _is_unique_query {
761 my ($self, $query) = @_;
763 my $collapsed = $self->_collapse_query($query);
764 my $alias = $self->{attrs}{alias};
766 foreach my $name ($self->result_source->unique_constraint_names) {
767 my @unique_cols = map {
769 } $self->result_source->unique_constraint_columns($name);
771 # Count the values for each unique column
772 my %seen = map { $_ => 0 } @unique_cols;
774 foreach my $key (keys %$collapsed) {
775 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
776 next unless exists $seen{$aliased}; # Additional constraints are okay
777 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
780 # If we get 0 or more than 1 value for a column, it's not necessarily unique
781 return 1 unless grep { $_ != 1 } values %seen;
789 # Recursively collapse the query, accumulating values for each column.
791 sub _collapse_query {
792 my ($self, $query, $collapsed) = @_;
796 if (ref $query eq 'ARRAY') {
797 foreach my $subquery (@$query) {
798 next unless ref $subquery; # -or
799 $collapsed = $self->_collapse_query($subquery, $collapsed);
802 elsif (ref $query eq 'HASH') {
803 if (keys %$query and (keys %$query)[0] eq '-and') {
804 foreach my $subquery (@{$query->{-and}}) {
805 $collapsed = $self->_collapse_query($subquery, $collapsed);
809 foreach my $col (keys %$query) {
810 my $value = $query->{$col};
811 $collapsed->{$col}{$value}++;
823 =item Arguments: $cond?
825 =item Return Value: $resultsetcolumn
829 my $max_length = $rs->get_column('length')->max;
831 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
836 my ($self, $column) = @_;
837 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
845 =item Arguments: $cond, \%attrs?
847 =item Return Value: $resultset (scalar context), @row_objs (list context)
851 # WHERE title LIKE '%blue%'
852 $cd_rs = $rs->search_like({ title => '%blue%'});
854 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
855 that this is simply a convenience method retained for ex Class::DBI users.
856 You most likely want to use L</search> with specific operators.
858 For more information, see L<DBIx::Class::Manual::Cookbook>.
860 This method is deprecated and will be removed in 0.09. Use L</search()>
861 instead. An example conversion is:
863 ->search_like({ foo => 'bar' });
867 ->search({ foo => { like => 'bar' } });
874 'search_like() is deprecated and will be removed in DBIC version 0.09.'
875 .' Instead use ->search({ x => { -like => "y%" } })'
876 .' (note the outer pair of {}s - they are important!)'
878 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
879 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
880 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
881 return $class->search($query, { %$attrs });
888 =item Arguments: $first, $last
890 =item Return Value: $resultset (scalar context), @row_objs (list context)
894 Returns a resultset or object list representing a subset of elements from the
895 resultset slice is called on. Indexes are from 0, i.e., to get the first
898 my ($one, $two, $three) = $rs->slice(0, 2);
903 my ($self, $min, $max) = @_;
904 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
905 $attrs->{offset} = $self->{attrs}{offset} || 0;
906 $attrs->{offset} += $min;
907 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
908 return $self->search(undef(), $attrs);
909 #my $slice = (ref $self)->new($self->result_source, $attrs);
910 #return (wantarray ? $slice->all : $slice);
917 =item Arguments: none
919 =item Return Value: $result?
923 Returns the next element in the resultset (C<undef> is there is none).
925 Can be used to efficiently iterate over records in the resultset:
927 my $rs = $schema->resultset('CD')->search;
928 while (my $cd = $rs->next) {
932 Note that you need to store the resultset object, and call C<next> on it.
933 Calling C<< resultset('Table')->next >> repeatedly will always return the
934 first record from the resultset.
940 if (my $cache = $self->get_cache) {
941 $self->{all_cache_position} ||= 0;
942 return $cache->[$self->{all_cache_position}++];
944 if ($self->{attrs}{cache}) {
945 $self->{all_cache_position} = 1;
946 return ($self->all)[0];
948 if ($self->{stashed_objects}) {
949 my $obj = shift(@{$self->{stashed_objects}});
950 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
954 exists $self->{stashed_row}
955 ? @{delete $self->{stashed_row}}
956 : $self->cursor->next
958 return undef unless (@row);
959 my ($row, @more) = $self->_construct_object(@row);
960 $self->{stashed_objects} = \@more if @more;
964 sub _construct_object {
965 my ($self, @row) = @_;
966 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
967 my @new = $self->result_class->inflate_result($self->result_source, @$info);
968 @new = $self->{_attrs}{record_filter}->(@new)
969 if exists $self->{_attrs}{record_filter};
973 sub _collapse_result {
974 my ($self, $as_proto, $row) = @_;
978 # 'foo' => [ undef, 'foo' ]
979 # 'foo.bar' => [ 'foo', 'bar' ]
980 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
982 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
984 my %collapse = %{$self->{_attrs}{collapse}||{}};
988 # if we're doing collapsing (has_many prefetch) we need to grab records
989 # until the PK changes, so fill @pri_index. if not, we leave it empty so
990 # we know we don't have to bother.
992 # the reason for not using the collapse stuff directly is because if you
993 # had for e.g. two artists in a row with no cds, the collapse info for
994 # both would be NULL (undef) so you'd lose the second artist
996 # store just the index so we can check the array positions from the row
997 # without having to contruct the full hash
999 if (keys %collapse) {
1000 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1001 foreach my $i (0 .. $#construct_as) {
1002 next if defined($construct_as[$i][0]); # only self table
1003 if (delete $pri{$construct_as[$i][1]}) {
1004 push(@pri_index, $i);
1006 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1010 # no need to do an if, it'll be empty if @pri_index is empty anyway
1012 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1016 do { # no need to check anything at the front, we always want the first row
1020 foreach my $this_as (@construct_as) {
1021 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1024 push(@const_rows, \%const);
1026 } until ( # no pri_index => no collapse => drop straight out
1029 do { # get another row, stash it, drop out if different PK
1031 @copy = $self->cursor->next;
1032 $self->{stashed_row} = \@copy;
1034 # last thing in do block, counts as true if anything doesn't match
1036 # check xor defined first for NULL vs. NOT NULL then if one is
1037 # defined the other must be so check string equality
1040 (defined $pri_vals{$_} ^ defined $copy[$_])
1041 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1046 my $alias = $self->{attrs}{alias};
1053 foreach my $const (@const_rows) {
1054 scalar @const_keys or do {
1055 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1057 foreach my $key (@const_keys) {
1060 my @parts = split(/\./, $key);
1062 my $data = $const->{$key};
1063 foreach my $p (@parts) {
1064 $target = $target->[1]->{$p} ||= [];
1066 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1067 # collapsing at this point and on final part
1068 my $pos = $collapse_pos{$cur};
1069 CK: foreach my $ck (@ckey) {
1070 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1071 $collapse_pos{$cur} = $data;
1072 delete @collapse_pos{ # clear all positioning for sub-entries
1073 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1080 if (exists $collapse{$cur}) {
1081 $target = $target->[-1];
1084 $target->[0] = $data;
1086 $info->[0] = $const->{$key};
1094 =head2 result_source
1098 =item Arguments: $result_source?
1100 =item Return Value: $result_source
1104 An accessor for the primary ResultSource object from which this ResultSet
1111 =item Arguments: $result_class?
1113 =item Return Value: $result_class
1117 An accessor for the class to use when creating row objects. Defaults to
1118 C<< result_source->result_class >> - which in most cases is the name of the
1119 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1121 Note that changing the result_class will also remove any components
1122 that were originally loaded in the source class via
1123 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1124 in the original source class will not run.
1129 my ($self, $result_class) = @_;
1130 if ($result_class) {
1131 $self->ensure_class_loaded($result_class);
1132 $self->_result_class($result_class);
1134 $self->_result_class;
1141 =item Arguments: $cond, \%attrs??
1143 =item Return Value: $count
1147 Performs an SQL C<COUNT> with the same query as the resultset was built
1148 with to find the number of elements. Passing arguments is equivalent to
1149 C<< $rs->search ($cond, \%attrs)->count >>
1155 return $self->search(@_)->count if @_ and defined $_[0];
1156 return scalar @{ $self->get_cache } if $self->get_cache;
1158 my $meth = $self->_has_attr (qw/prefetch collapse distinct group_by/)
1163 my $attrs = $self->_resolved_attrs_copy;
1164 my $rsrc = $self->result_source;
1166 return $rsrc->storage->$meth ($rsrc, $attrs);
1173 =head2 count_literal
1177 =item Arguments: $sql_fragment, @bind_values
1179 =item Return Value: $count
1183 Counts the results in a literal query. Equivalent to calling L</search_literal>
1184 with the passed arguments, then L</count>.
1188 sub count_literal { shift->search_literal(@_)->count; }
1194 =item Arguments: none
1196 =item Return Value: @objects
1200 Returns all elements in the resultset. Called implicitly if the resultset
1201 is returned in list context.
1208 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1211 return @{ $self->get_cache } if $self->get_cache;
1215 # TODO: don't call resolve here
1216 if (keys %{$self->_resolved_attrs->{collapse}}) {
1217 # if ($self->{attrs}{prefetch}) {
1218 # Using $self->cursor->all is really just an optimisation.
1219 # If we're collapsing has_many prefetches it probably makes
1220 # very little difference, and this is cleaner than hacking
1221 # _construct_object to survive the approach
1222 my @row = $self->cursor->next;
1224 push(@obj, $self->_construct_object(@row));
1225 @row = (exists $self->{stashed_row}
1226 ? @{delete $self->{stashed_row}}
1227 : $self->cursor->next);
1230 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1233 $self->set_cache(\@obj) if $self->{attrs}{cache};
1241 =item Arguments: none
1243 =item Return Value: $self
1247 Resets the resultset's cursor, so you can iterate through the elements again.
1253 delete $self->{_attrs} if exists $self->{_attrs};
1254 $self->{all_cache_position} = 0;
1255 $self->cursor->reset;
1263 =item Arguments: none
1265 =item Return Value: $object?
1269 Resets the resultset and returns an object for the first result (if the
1270 resultset returns anything).
1275 return $_[0]->reset->next;
1281 # Determines whether and what type of subquery is required for the $rs operation.
1282 # If grouping is necessary either supplies its own, or verifies the current one
1283 # After all is done delegates to the proper storage method.
1285 sub _rs_update_delete {
1286 my ($self, $op, $values) = @_;
1288 my $rsrc = $self->result_source;
1290 my $needs_group_by_subq = $self->_has_attr (qw/prefetch distinct join seen_join group_by/);
1291 my $needs_subq = $self->_has_attr (qw/row offset page/);
1293 if ($needs_group_by_subq or $needs_subq) {
1295 # make a new $rs selecting only the PKs (that's all we really need)
1296 my $attrs = $self->_resolved_attrs_copy;
1298 delete $attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns/;
1299 $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
1301 if ($needs_group_by_subq) {
1302 # make sure no group_by was supplied, or if there is one - make sure it matches
1303 # the columns compiled above perfectly. Anything else can not be sanely executed
1304 # on most databases so croak right then and there
1306 if (my $g = $attrs->{group_by}) {
1307 my @current_group_by = map
1308 { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
1309 (ref $g eq 'ARRAY' ? @$g : $g );
1312 join ("\x00", sort @current_group_by)
1314 join ("\x00", sort @{$attrs->{columns}} )
1316 $self->throw_exception (
1317 "You have just attempted a $op operation on a resultset which does group_by"
1318 . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
1319 . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
1320 . ' kind of queries. Please retry the operation with a modified group_by or'
1321 . ' without using one at all.'
1326 $attrs->{group_by} = $attrs->{columns};
1330 my $subrs = (ref $self)->new($rsrc, $attrs);
1332 return $self->result_source->storage->subq_update_delete($subrs, $op, $values);
1335 return $rsrc->storage->$op(
1337 $op eq 'update' ? $values : (),
1338 $self->_cond_for_update_delete,
1344 # _cond_for_update_delete
1346 # update/delete require the condition to be modified to handle
1347 # the differing SQL syntax available. This transforms the $self->{cond}
1348 # appropriately, returning the new condition.
1350 sub _cond_for_update_delete {
1351 my ($self, $full_cond) = @_;
1354 $full_cond ||= $self->{cond};
1355 # No-op. No condition, we're updating/deleting everything
1356 return $cond unless ref $full_cond;
1358 if (ref $full_cond eq 'ARRAY') {
1362 foreach my $key (keys %{$_}) {
1364 $hash{$1} = $_->{$key};
1370 elsif (ref $full_cond eq 'HASH') {
1371 if ((keys %{$full_cond})[0] eq '-and') {
1373 my @cond = @{$full_cond->{-and}};
1374 for (my $i = 0; $i < @cond; $i++) {
1375 my $entry = $cond[$i];
1377 if (ref $entry eq 'HASH') {
1378 $hash = $self->_cond_for_update_delete($entry);
1381 $entry =~ /([^.]+)$/;
1382 $hash->{$1} = $cond[++$i];
1384 push @{$cond->{-and}}, $hash;
1388 foreach my $key (keys %{$full_cond}) {
1390 $cond->{$1} = $full_cond->{$key};
1395 $self->throw_exception("Can't update/delete on resultset with condition unless hash or array");
1406 =item Arguments: \%values
1408 =item Return Value: $storage_rv
1412 Sets the specified columns in the resultset to the supplied values in a
1413 single query. Return value will be true if the update succeeded or false
1414 if no records were updated; exact type of success value is storage-dependent.
1419 my ($self, $values) = @_;
1420 $self->throw_exception('Values for update must be a hash')
1421 unless ref $values eq 'HASH';
1423 return $self->_rs_update_delete ('update', $values);
1430 =item Arguments: \%values
1432 =item Return Value: 1
1436 Fetches all objects and updates them one at a time. Note that C<update_all>
1437 will run DBIC cascade triggers, while L</update> will not.
1442 my ($self, $values) = @_;
1443 $self->throw_exception('Values for update_all must be a hash')
1444 unless ref $values eq 'HASH';
1445 foreach my $obj ($self->all) {
1446 $obj->set_columns($values)->update;
1455 =item Arguments: none
1457 =item Return Value: $storage_rv
1461 Deletes the contents of the resultset from its result source. Note that this
1462 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1463 to run. See also L<DBIx::Class::Row/delete>.
1465 Return value will be the amount of rows deleted; exact type of return value
1466 is storage-dependent.
1472 $self->throw_exception('delete does not accept any arguments')
1475 return $self->_rs_update_delete ('delete');
1482 =item Arguments: none
1484 =item Return Value: 1
1488 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1489 will run DBIC cascade triggers, while L</delete> will not.
1495 $self->throw_exception('delete_all does not accept any arguments')
1498 $_->delete for $self->all;
1506 =item Arguments: \@data;
1510 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1511 For the arrayref of hashrefs style each hashref should be a structure suitable
1512 forsubmitting to a $resultset->create(...) method.
1514 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1515 to insert the data, as this is a faster method.
1517 Otherwise, each set of data is inserted into the database using
1518 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1519 objects is returned.
1521 Example: Assuming an Artist Class that has many CDs Classes relating:
1523 my $Artist_rs = $schema->resultset("Artist");
1525 ## Void Context Example
1526 $Artist_rs->populate([
1527 { artistid => 4, name => 'Manufactured Crap', cds => [
1528 { title => 'My First CD', year => 2006 },
1529 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1532 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1533 { title => 'My parents sold me to a record company' ,year => 2005 },
1534 { title => 'Why Am I So Ugly?', year => 2006 },
1535 { title => 'I Got Surgery and am now Popular', year => 2007 }
1540 ## Array Context Example
1541 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1542 { name => "Artist One"},
1543 { name => "Artist Two"},
1544 { name => "Artist Three", cds=> [
1545 { title => "First CD", year => 2007},
1546 { title => "Second CD", year => 2008},
1550 print $ArtistOne->name; ## response is 'Artist One'
1551 print $ArtistThree->cds->count ## reponse is '2'
1553 For the arrayref of arrayrefs style, the first element should be a list of the
1554 fieldsnames to which the remaining elements are rows being inserted. For
1557 $Arstist_rs->populate([
1558 [qw/artistid name/],
1559 [100, 'A Formally Unknown Singer'],
1560 [101, 'A singer that jumped the shark two albums ago'],
1561 [102, 'An actually cool singer.'],
1564 Please note an important effect on your data when choosing between void and
1565 wantarray context. Since void context goes straight to C<insert_bulk> in
1566 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1567 C<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1568 create primary keys for you, you will find that your PKs are empty. In this
1569 case you will have to use the wantarray context in order to create those
1575 my $self = shift @_;
1576 my $data = ref $_[0][0] eq 'HASH'
1577 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1578 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1580 if(defined wantarray) {
1582 foreach my $item (@$data) {
1583 push(@created, $self->create($item));
1587 my ($first, @rest) = @$data;
1589 my @names = grep {!ref $first->{$_}} keys %$first;
1590 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1591 my @pks = $self->result_source->primary_columns;
1593 ## do the belongs_to relationships
1594 foreach my $index (0..$#$data) {
1596 # delegate to create() for any dataset without primary keys with specified relationships
1597 if (grep { !defined $data->[$index]->{$_} } @pks ) {
1599 if (grep { ref $data->[$index]{$r} eq $_ } qw/HASH ARRAY/) { # a related set must be a HASH or AoH
1600 my @ret = $self->populate($data);
1606 foreach my $rel (@rels) {
1607 next unless ref $data->[$index]->{$rel} eq "HASH";
1608 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1609 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1610 my $related = $result->result_source->_resolve_condition(
1611 $result->result_source->relationship_info($reverse)->{cond},
1616 delete $data->[$index]->{$rel};
1617 $data->[$index] = {%{$data->[$index]}, %$related};
1619 push @names, keys %$related if $index == 0;
1623 ## do bulk insert on current row
1624 my @values = map { [ @$_{@names} ] } @$data;
1626 $self->result_source->storage->insert_bulk(
1627 $self->result_source,
1632 ## do the has_many relationships
1633 foreach my $item (@$data) {
1635 foreach my $rel (@rels) {
1636 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1638 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1639 || $self->throw_exception('Cannot find the relating object.');
1641 my $child = $parent->$rel;
1643 my $related = $child->result_source->_resolve_condition(
1644 $parent->result_source->relationship_info($rel)->{cond},
1649 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1650 my @populate = map { {%$_, %$related} } @rows_to_add;
1652 $child->populate( \@populate );
1658 =head2 _normalize_populate_args ($args)
1660 Private method used by L</populate> to normalize its incoming arguments. Factored
1661 out in case you want to subclass and accept new argument structures to the
1662 L</populate> method.
1666 sub _normalize_populate_args {
1667 my ($self, $data) = @_;
1668 my @names = @{shift(@$data)};
1669 my @results_to_create;
1670 foreach my $datum (@$data) {
1671 my %result_to_create;
1672 foreach my $index (0..$#names) {
1673 $result_to_create{$names[$index]} = $$datum[$index];
1675 push @results_to_create, \%result_to_create;
1677 return \@results_to_create;
1684 =item Arguments: none
1686 =item Return Value: $pager
1690 Return Value a L<Data::Page> object for the current resultset. Only makes
1691 sense for queries with a C<page> attribute.
1693 To get the full count of entries for a paged resultset, call
1694 C<total_entries> on the L<Data::Page> object.
1701 return $self->{pager} if $self->{pager};
1703 my $attrs = $self->{attrs};
1704 $self->throw_exception("Can't create pager for non-paged rs")
1705 unless $self->{attrs}{page};
1706 $attrs->{rows} ||= 10;
1708 # throw away the paging flags and re-run the count (possibly
1709 # with a subselect) to get the real total count
1710 my $count_attrs = { %$attrs };
1711 delete $count_attrs->{$_} for qw/rows offset page pager/;
1712 my $total_count = (ref $self)->new($self->result_source, $count_attrs)->count;
1714 return $self->{pager} = Data::Page->new(
1717 $self->{attrs}{page}
1725 =item Arguments: $page_number
1727 =item Return Value: $rs
1731 Returns a resultset for the $page_number page of the resultset on which page
1732 is called, where each page contains a number of rows equal to the 'rows'
1733 attribute set on the resultset (10 by default).
1738 my ($self, $page) = @_;
1739 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1746 =item Arguments: \%vals
1748 =item Return Value: $rowobject
1752 Creates a new row object in the resultset's result class and returns
1753 it. The row is not inserted into the database at this point, call
1754 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1755 will tell you whether the row object has been inserted or not.
1757 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1762 my ($self, $values) = @_;
1763 $self->throw_exception( "new_result needs a hash" )
1764 unless (ref $values eq 'HASH');
1767 my $alias = $self->{attrs}{alias};
1770 defined $self->{cond}
1771 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1773 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1774 $new{-from_resultset} = [ keys %new ] if keys %new;
1776 $self->throw_exception(
1777 "Can't abstract implicit construct, condition not a hash"
1778 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1780 my $collapsed_cond = (
1782 ? $self->_collapse_cond($self->{cond})
1786 # precendence must be given to passed values over values inherited from
1787 # the cond, so the order here is important.
1788 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1789 while( my($col,$value) = each %implied ){
1790 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1791 $new{$col} = $value->{'='};
1794 $new{$col} = $value if $self->_is_deterministic_value($value);
1800 %{ $self->_remove_alias($values, $alias) },
1801 -source_handle => $self->_source_handle,
1802 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1805 return $self->result_class->new(\%new);
1808 # _is_deterministic_value
1810 # Make an effor to strip non-deterministic values from the condition,
1811 # to make sure new_result chokes less
1813 sub _is_deterministic_value {
1816 my $ref_type = ref $value;
1817 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1818 return 1 if Scalar::Util::blessed($value);
1824 # determines if the resultset defines at least one
1825 # of the attributes supplied
1827 # used to determine if a subquery is neccessary
1830 my ($self, @attr_names) = @_;
1832 my $attrs = $self->_resolved_attrs;
1836 for my $n (@attr_names) {
1837 ++$join_check_req if $n =~ /join/;
1839 my $attr = $attrs->{$n};
1841 next if not defined $attr;
1843 if (ref $attr eq 'HASH') {
1844 return 1 if keys %$attr;
1846 elsif (ref $attr eq 'ARRAY') {
1854 # a join can be expressed as a multi-level from
1858 ref $attrs->{from} eq 'ARRAY'
1860 @{$attrs->{from}} > 1
1868 # Recursively collapse the condition.
1870 sub _collapse_cond {
1871 my ($self, $cond, $collapsed) = @_;
1875 if (ref $cond eq 'ARRAY') {
1876 foreach my $subcond (@$cond) {
1877 next unless ref $subcond; # -or
1878 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1881 elsif (ref $cond eq 'HASH') {
1882 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1883 foreach my $subcond (@{$cond->{-and}}) {
1884 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1888 foreach my $col (keys %$cond) {
1889 my $value = $cond->{$col};
1890 $collapsed->{$col} = $value;
1900 # Remove the specified alias from the specified query hash. A copy is made so
1901 # the original query is not modified.
1904 my ($self, $query, $alias) = @_;
1906 my %orig = %{ $query || {} };
1909 foreach my $key (keys %orig) {
1911 $unaliased{$key} = $orig{$key};
1914 $unaliased{$1} = $orig{$key}
1915 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1921 =head2 as_query (EXPERIMENTAL)
1925 =item Arguments: none
1927 =item Return Value: \[ $sql, @bind ]
1931 Returns the SQL query and bind vars associated with the invocant.
1933 This is generally used as the RHS for a subquery.
1935 B<NOTE>: This feature is still experimental.
1939 sub as_query { return shift->cursor->as_query(@_) }
1945 =item Arguments: \%vals, \%attrs?
1947 =item Return Value: $rowobject
1951 my $artist = $schema->resultset('Artist')->find_or_new(
1952 { artist => 'fred' }, { key => 'artists' });
1954 $cd->cd_to_producer->find_or_new({ producer => $producer },
1955 { key => 'primary });
1957 Find an existing record from this resultset, based on its primary
1958 key, or a unique constraint. If none exists, instantiate a new result
1959 object and return it. The object will not be saved into your storage
1960 until you call L<DBIx::Class::Row/insert> on it.
1962 You most likely want this method when looking for existing rows using
1963 a unique constraint that is not the primary key, or looking for
1966 If you want objects to be saved immediately, use L</find_or_create> instead.
1968 B<Note>: C<find_or_new> is probably not what you want when creating a
1969 new row in a table that uses primary keys supplied by the
1970 database. Passing in a primary key column with a value of I<undef>
1971 will cause L</find> to attempt to search for a row with a value of
1978 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1979 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1980 my $exists = $self->find($hash, $attrs);
1981 return defined $exists ? $exists : $self->new_result($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 my $exists = $self->find($hash, $attrs);
2112 return defined $exists ? $exists : $self->create($hash);
2115 =head2 update_or_create
2119 =item Arguments: \%col_values, { key => $unique_constraint }?
2121 =item Return Value: $rowobject
2125 $resultset->update_or_create({ col => $val, ... });
2127 First, searches for an existing row matching one of the unique constraints
2128 (including the primary key) on the source of this resultset. If a row is
2129 found, updates it with the other given column values. Otherwise, creates a new
2132 Takes an optional C<key> attribute to search on a specific unique constraint.
2135 # In your application
2136 my $cd = $schema->resultset('CD')->update_or_create(
2138 artist => 'Massive Attack',
2139 title => 'Mezzanine',
2142 { key => 'cd_artist_title' }
2145 $cd->cd_to_producer->update_or_create({
2146 producer => $producer,
2153 If no C<key> is specified, it searches on all unique constraints defined on the
2154 source, including the primary key.
2156 If the C<key> is specified as C<primary>, it searches only on the primary key.
2158 See also L</find> and L</find_or_create>. For information on how to declare
2159 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2161 B<Note>: C<update_or_create> is probably not what you want when
2162 looking for a row in a table that uses primary keys supplied by the
2163 database, unless you actually have a key value. Passing in a primary
2164 key column with a value of I<undef> will cause L</find> to attempt to
2165 search for a row with a value of I<NULL>.
2169 sub update_or_create {
2171 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2172 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2174 my $row = $self->find($cond, $attrs);
2176 $row->update($cond);
2180 return $self->create($cond);
2183 =head2 update_or_new
2187 =item Arguments: \%col_values, { key => $unique_constraint }?
2189 =item Return Value: $rowobject
2193 $resultset->update_or_new({ col => $val, ... });
2195 First, searches for an existing row matching one of the unique constraints
2196 (including the primary key) on the source of this resultset. If a row is
2197 found, updates it with the other given column values. Otherwise, instantiate
2198 a new result object and return it. The object will not be saved into your storage
2199 until you call L<DBIx::Class::Row/insert> on it.
2201 Takes an optional C<key> attribute to search on a specific unique constraint.
2204 # In your application
2205 my $cd = $schema->resultset('CD')->update_or_new(
2207 artist => 'Massive Attack',
2208 title => 'Mezzanine',
2211 { key => 'cd_artist_title' }
2214 if ($cd->in_storage) {
2215 # the cd was updated
2218 # the cd is not yet in the database, let's insert it
2222 See also L</find>, L</find_or_create> and L<find_or_new>.
2228 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2229 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2231 my $row = $self->find( $cond, $attrs );
2232 if ( defined $row ) {
2233 $row->update($cond);
2237 return $self->new_result($cond);
2244 =item Arguments: none
2246 =item Return Value: \@cache_objects?
2250 Gets the contents of the cache for the resultset, if the cache is set.
2252 The cache is populated either by using the L</prefetch> attribute to
2253 L</search> or by calling L</set_cache>.
2265 =item Arguments: \@cache_objects
2267 =item Return Value: \@cache_objects
2271 Sets the contents of the cache for the resultset. Expects an arrayref
2272 of objects of the same class as those produced by the resultset. Note that
2273 if the cache is set the resultset will return the cached objects rather
2274 than re-querying the database even if the cache attr is not set.
2276 The contents of the cache can also be populated by using the
2277 L</prefetch> attribute to L</search>.
2282 my ( $self, $data ) = @_;
2283 $self->throw_exception("set_cache requires an arrayref")
2284 if defined($data) && (ref $data ne 'ARRAY');
2285 $self->{all_cache} = $data;
2292 =item Arguments: none
2294 =item Return Value: []
2298 Clears the cache for the resultset.
2303 shift->set_cache(undef);
2306 =head2 related_resultset
2310 =item Arguments: $relationship_name
2312 =item Return Value: $resultset
2316 Returns a related resultset for the supplied relationship name.
2318 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2322 sub related_resultset {
2323 my ($self, $rel) = @_;
2325 $self->{related_resultsets} ||= {};
2326 return $self->{related_resultsets}{$rel} ||= do {
2327 my $rel_obj = $self->result_source->relationship_info($rel);
2329 $self->throw_exception(
2330 "search_related: result source '" . $self->result_source->source_name .
2331 "' has no such relationship $rel")
2334 my ($from,$seen) = $self->_resolve_from($rel);
2336 my $join_count = $seen->{$rel};
2337 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2339 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2340 my %attrs = %{$self->{attrs}||{}};
2341 delete @attrs{qw(result_class alias)};
2345 if (my $cache = $self->get_cache) {
2346 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2347 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2352 my $rel_source = $self->result_source->related_source($rel);
2356 # The reason we do this now instead of passing the alias to the
2357 # search_rs below is that if you wrap/overload resultset on the
2358 # source you need to know what alias it's -going- to have for things
2359 # to work sanely (e.g. RestrictWithObject wants to be able to add
2360 # extra query restrictions, and these may need to be $alias.)
2362 my $attrs = $rel_source->resultset_attributes;
2363 local $attrs->{alias} = $alias;
2365 $rel_source->resultset
2373 where => $self->{cond},
2378 $new->set_cache($new_cache) if $new_cache;
2383 =head2 current_source_alias
2387 =item Arguments: none
2389 =item Return Value: $source_alias
2393 Returns the current table alias for the result source this resultset is built
2394 on, that will be used in the SQL query. Usually it is C<me>.
2396 Currently the source alias that refers to the result set returned by a
2397 L</search>/L</find> family method depends on how you got to the resultset: it's
2398 C<me> by default, but eg. L</search_related> aliases it to the related result
2399 source name (and keeps C<me> referring to the original result set). The long
2400 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2401 (and make this method unnecessary).
2403 Thus it's currently necessary to use this method in predefined queries (see
2404 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2405 source alias of the current result set:
2407 # in a result set class
2409 my ($self, $user) = @_;
2411 my $me = $self->current_source_alias;
2413 return $self->search(
2414 "$me.modified" => $user->id,
2420 sub current_source_alias {
2423 return ($self->{attrs} || {})->{alias} || 'me';
2426 # This code is called by search_related, and makes sure there
2427 # is clear separation between the joins before, during, and
2428 # after the relationship. This information is needed later
2429 # in order to properly resolve prefetch aliases (any alias
2430 # with a relation_chain_depth less than the depth of the
2431 # current prefetch is not considered)
2433 my ($self, $extra_join) = @_;
2434 my $source = $self->result_source;
2435 my $attrs = $self->{attrs};
2437 my $from = $attrs->{from}
2438 || [ { $attrs->{alias} => $source->from } ];
2440 my $seen = $attrs->{seen_join} || {};
2442 # we need to take the prefetch the attrs into account before we
2443 # ->_resolve_join as otherwise they get lost - captainL
2444 my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
2446 push @$from, $source->_resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
2448 ++$seen->{-relation_chain_depth};
2450 push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
2452 ++$seen->{-relation_chain_depth};
2454 return ($from,$seen);
2457 # too many times we have to do $attrs = { %{$self->_resolved_attrs} }
2458 sub _resolved_attrs_copy {
2460 return { %{$self->_resolved_attrs (@_)} };
2463 sub _resolved_attrs {
2465 return $self->{_attrs} if $self->{_attrs};
2467 my $attrs = { %{ $self->{attrs} || {} } };
2468 my $source = $self->result_source;
2469 my $alias = $attrs->{alias};
2471 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2474 # build columns (as long as select isn't set) into a set of as/select hashes
2475 unless ( $attrs->{select} ) {
2477 ( ref($_) eq 'HASH' )
2481 /^\Q${alias}.\E(.+)$/
2492 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2494 # add the additional columns on
2495 foreach ( 'include_columns', '+columns' ) {
2496 push @colbits, map {
2497 ( ref($_) eq 'HASH' )
2499 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2500 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2503 # start with initial select items
2504 if ( $attrs->{select} ) {
2506 ( ref $attrs->{select} eq 'ARRAY' )
2507 ? [ @{ $attrs->{select} } ]
2508 : [ $attrs->{select} ];
2512 ref $attrs->{as} eq 'ARRAY'
2513 ? [ @{ $attrs->{as} } ]
2516 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2521 # otherwise we intialise select & as to empty
2522 $attrs->{select} = [];
2526 # now add colbits to select/as
2527 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2528 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2531 if ( $adds = delete $attrs->{'+select'} ) {
2532 $adds = [$adds] unless ref $adds eq 'ARRAY';
2534 @{ $attrs->{select} },
2535 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2538 if ( $adds = delete $attrs->{'+as'} ) {
2539 $adds = [$adds] unless ref $adds eq 'ARRAY';
2540 push( @{ $attrs->{as} }, @$adds );
2543 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2545 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2546 my $join = delete $attrs->{join} || {};
2548 if ( defined $attrs->{prefetch} ) {
2549 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2553 $attrs->{from} = # have to copy here to avoid corrupting the original
2555 @{ $attrs->{from} },
2556 $source->_resolve_join(
2557 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2563 if ( $attrs->{order_by} ) {
2564 $attrs->{order_by} = (
2565 ref( $attrs->{order_by} ) eq 'ARRAY'
2566 ? [ @{ $attrs->{order_by} } ]
2567 : [ $attrs->{order_by} ]
2571 $attrs->{order_by} = [];
2574 my $collapse = $attrs->{collapse} || {};
2575 if ( my $prefetch = delete $attrs->{prefetch} ) {
2576 $prefetch = $self->_merge_attr( {}, $prefetch );
2578 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2580 # bring joins back to level of current class
2581 my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
2583 $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
2584 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2585 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2587 push( @{ $attrs->{order_by} }, @pre_order );
2590 if (delete $attrs->{distinct}) {
2591 $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
2594 $attrs->{collapse} = $collapse;
2596 if ( $attrs->{page} and not defined $attrs->{offset} ) {
2597 $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2600 return $self->{_attrs} = $attrs;
2603 sub _joinpath_aliases {
2604 my ($self, $fromspec, $seen) = @_;
2607 return $paths unless ref $fromspec eq 'ARRAY';
2609 for my $j (@$fromspec) {
2611 next if ref $j ne 'ARRAY';
2612 next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
2615 $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
2616 push @{$p->{-join_aliases} }, $j->[0]{-join_alias};
2623 my ($self, $attr) = @_;
2625 if (ref $attr eq 'HASH') {
2626 return $self->_rollout_hash($attr);
2627 } elsif (ref $attr eq 'ARRAY') {
2628 return $self->_rollout_array($attr);
2634 sub _rollout_array {
2635 my ($self, $attr) = @_;
2638 foreach my $element (@{$attr}) {
2639 if (ref $element eq 'HASH') {
2640 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2641 } elsif (ref $element eq 'ARRAY') {
2642 # XXX - should probably recurse here
2643 push( @rolled_array, @{$self->_rollout_array($element)} );
2645 push( @rolled_array, $element );
2648 return \@rolled_array;
2652 my ($self, $attr) = @_;
2655 foreach my $key (keys %{$attr}) {
2656 push( @rolled_array, { $key => $attr->{$key} } );
2658 return \@rolled_array;
2661 sub _calculate_score {
2662 my ($self, $a, $b) = @_;
2664 if (ref $b eq 'HASH') {
2665 my ($b_key) = keys %{$b};
2666 if (ref $a eq 'HASH') {
2667 my ($a_key) = keys %{$a};
2668 if ($a_key eq $b_key) {
2669 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2674 return ($a eq $b_key) ? 1 : 0;
2677 if (ref $a eq 'HASH') {
2678 my ($a_key) = keys %{$a};
2679 return ($b eq $a_key) ? 1 : 0;
2681 return ($b eq $a) ? 1 : 0;
2687 my ($self, $orig, $import) = @_;
2689 return $import unless defined($orig);
2690 return $orig unless defined($import);
2692 $orig = $self->_rollout_attr($orig);
2693 $import = $self->_rollout_attr($import);
2696 foreach my $import_element ( @{$import} ) {
2697 # find best candidate from $orig to merge $b_element into
2698 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2699 foreach my $orig_element ( @{$orig} ) {
2700 my $score = $self->_calculate_score( $orig_element, $import_element );
2701 if ($score > $best_candidate->{score}) {
2702 $best_candidate->{position} = $position;
2703 $best_candidate->{score} = $score;
2707 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2709 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2710 push( @{$orig}, $import_element );
2712 my $orig_best = $orig->[$best_candidate->{position}];
2713 # merge orig_best and b_element together and replace original with merged
2714 if (ref $orig_best ne 'HASH') {
2715 $orig->[$best_candidate->{position}] = $import_element;
2716 } elsif (ref $import_element eq 'HASH') {
2717 my ($key) = keys %{$orig_best};
2718 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2721 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2731 $self->_source_handle($_[0]->handle);
2733 $self->_source_handle->resolve;
2737 =head2 throw_exception
2739 See L<DBIx::Class::Schema/throw_exception> for details.
2743 sub throw_exception {
2745 if (ref $self && $self->_source_handle->schema) {
2746 $self->_source_handle->schema->throw_exception(@_)
2753 # XXX: FIXME: Attributes docs need clearing up
2757 Attributes are used to refine a ResultSet in various ways when
2758 searching for data. They can be passed to any method which takes an
2759 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2762 These are in no particular order:
2768 =item Value: ( $order_by | \@order_by | \%order_by )
2772 Which column(s) to order the results by. If a single column name, or
2773 an arrayref of names is supplied, the argument is passed through
2774 directly to SQL. The hashref syntax allows for connection-agnostic
2775 specification of ordering direction:
2777 For descending order:
2779 order_by => { -desc => [qw/col1 col2 col3/] }
2781 For explicit ascending order:
2783 order_by => { -asc => 'col' }
2785 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2786 supported, although you are strongly encouraged to use the hashref
2787 syntax as outlined above.
2793 =item Value: \@columns
2797 Shortcut to request a particular set of columns to be retrieved. Each
2798 column spec may be a string (a table column name), or a hash (in which
2799 case the key is the C<as> value, and the value is used as the C<select>
2800 expression). Adds C<me.> onto the start of any column without a C<.> in
2801 it and sets C<select> from that, then auto-populates C<as> from
2802 C<select> as normal. (You may also use the C<cols> attribute, as in
2803 earlier versions of DBIC.)
2809 =item Value: \@columns
2813 Indicates additional columns to be selected from storage. Works the same
2814 as L</columns> but adds columns to the selection. (You may also use the
2815 C<include_columns> attribute, as in earlier versions of DBIC). For
2818 $schema->resultset('CD')->search(undef, {
2819 '+columns' => ['artist.name'],
2823 would return all CDs and include a 'name' column to the information
2824 passed to object inflation. Note that the 'artist' is the name of the
2825 column (or relationship) accessor, and 'name' is the name of the column
2826 accessor in the related table.
2828 =head2 include_columns
2832 =item Value: \@columns
2836 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2842 =item Value: \@select_columns
2846 Indicates which columns should be selected from the storage. You can use
2847 column names, or in the case of RDBMS back ends, function or stored procedure
2850 $rs = $schema->resultset('Employee')->search(undef, {
2853 { count => 'employeeid' },
2858 When you use function/stored procedure names and do not supply an C<as>
2859 attribute, the column names returned are storage-dependent. E.g. MySQL would
2860 return a column named C<count(employeeid)> in the above example.
2866 Indicates additional columns to be selected from storage. Works the same as
2867 L</select> but adds columns to the selection.
2875 Indicates additional column names for those added via L</+select>. See L</as>.
2883 =item Value: \@inflation_names
2887 Indicates column names for object inflation. That is, C<as>
2888 indicates the name that the column can be accessed as via the
2889 C<get_column> method (or via the object accessor, B<if one already
2890 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2892 The C<as> attribute is used in conjunction with C<select>,
2893 usually when C<select> contains one or more function or stored
2896 $rs = $schema->resultset('Employee')->search(undef, {
2899 { count => 'employeeid' }
2901 as => ['name', 'employee_count'],
2904 my $employee = $rs->first(); # get the first Employee
2906 If the object against which the search is performed already has an accessor
2907 matching a column name specified in C<as>, the value can be retrieved using
2908 the accessor as normal:
2910 my $name = $employee->name();
2912 If on the other hand an accessor does not exist in the object, you need to
2913 use C<get_column> instead:
2915 my $employee_count = $employee->get_column('employee_count');
2917 You can create your own accessors if required - see
2918 L<DBIx::Class::Manual::Cookbook> for details.
2920 Please note: This will NOT insert an C<AS employee_count> into the SQL
2921 statement produced, it is used for internal access only. Thus
2922 attempting to use the accessor in an C<order_by> clause or similar
2923 will fail miserably.
2925 To get around this limitation, you can supply literal SQL to your
2926 C<select> attibute that contains the C<AS alias> text, eg:
2928 select => [\'myfield AS alias']
2934 =item Value: ($rel_name | \@rel_names | \%rel_names)
2938 Contains a list of relationships that should be joined for this query. For
2941 # Get CDs by Nine Inch Nails
2942 my $rs = $schema->resultset('CD')->search(
2943 { 'artist.name' => 'Nine Inch Nails' },
2944 { join => 'artist' }
2947 Can also contain a hash reference to refer to the other relation's relations.
2950 package MyApp::Schema::Track;
2951 use base qw/DBIx::Class/;
2952 __PACKAGE__->table('track');
2953 __PACKAGE__->add_columns(qw/trackid cd position title/);
2954 __PACKAGE__->set_primary_key('trackid');
2955 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2958 # In your application
2959 my $rs = $schema->resultset('Artist')->search(
2960 { 'track.title' => 'Teardrop' },
2962 join => { cd => 'track' },
2963 order_by => 'artist.name',
2967 You need to use the relationship (not the table) name in conditions,
2968 because they are aliased as such. The current table is aliased as "me", so
2969 you need to use me.column_name in order to avoid ambiguity. For example:
2971 # Get CDs from 1984 with a 'Foo' track
2972 my $rs = $schema->resultset('CD')->search(
2975 'tracks.name' => 'Foo'
2977 { join => 'tracks' }
2980 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2981 similarly for a third time). For e.g.
2983 my $rs = $schema->resultset('Artist')->search({
2984 'cds.title' => 'Down to Earth',
2985 'cds_2.title' => 'Popular',
2987 join => [ qw/cds cds/ ],
2990 will return a set of all artists that have both a cd with title 'Down
2991 to Earth' and a cd with title 'Popular'.
2993 If you want to fetch related objects from other tables as well, see C<prefetch>
2996 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
3002 =item Value: ($rel_name | \@rel_names | \%rel_names)
3006 Contains one or more relationships that should be fetched along with
3007 the main query (when they are accessed afterwards the data will
3008 already be available, without extra queries to the database). This is
3009 useful for when you know you will need the related objects, because it
3010 saves at least one query:
3012 my $rs = $schema->resultset('Tag')->search(
3021 The initial search results in SQL like the following:
3023 SELECT tag.*, cd.*, artist.* FROM tag
3024 JOIN cd ON tag.cd = cd.cdid
3025 JOIN artist ON cd.artist = artist.artistid
3027 L<DBIx::Class> has no need to go back to the database when we access the
3028 C<cd> or C<artist> relationships, which saves us two SQL statements in this
3031 Simple prefetches will be joined automatically, so there is no need
3032 for a C<join> attribute in the above search.
3034 C<prefetch> can be used with the following relationship types: C<belongs_to>,
3035 C<has_one> (or if you're using C<add_relationship>, any relationship declared
3036 with an accessor type of 'single' or 'filter'). A more complex example that
3037 prefetches an artists cds, the tracks on those cds, and the tags associted
3038 with that artist is given below (assuming many-to-many from artists to tags):
3040 my $rs = $schema->resultset('Artist')->search(
3044 { cds => 'tracks' },
3045 { artist_tags => 'tags' }
3051 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
3052 attributes will be ignored.
3062 Makes the resultset paged and specifies the page to retrieve. Effectively
3063 identical to creating a non-pages resultset and then calling ->page($page)
3066 If L<rows> attribute is not specified it defualts to 10 rows per page.
3068 When you have a paged resultset, L</count> will only return the number
3069 of rows in the page. To get the total, use the L</pager> and call
3070 C<total_entries> on it.
3080 Specifes the maximum number of rows for direct retrieval or the number of
3081 rows per page if the page attribute or method is used.
3087 =item Value: $offset
3091 Specifies the (zero-based) row number for the first row to be returned, or the
3092 of the first row of the first page if paging is used.
3098 =item Value: \@columns
3102 A arrayref of columns to group by. Can include columns of joined tables.
3104 group_by => [qw/ column1 column2 ... /]
3110 =item Value: $condition
3114 HAVING is a select statement attribute that is applied between GROUP BY and
3115 ORDER BY. It is applied to the after the grouping calculations have been
3118 having => { 'count(employee)' => { '>=', 100 } }
3124 =item Value: (0 | 1)
3128 Set to 1 to group by all columns.
3134 Adds to the WHERE clause.
3136 # only return rows WHERE deleted IS NULL for all searches
3137 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3139 Can be overridden by passing C<{ where => undef }> as an attribute
3146 Set to 1 to cache search results. This prevents extra SQL queries if you
3147 revisit rows in your ResultSet:
3149 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3151 while( my $artist = $resultset->next ) {
3155 $rs->first; # without cache, this would issue a query
3157 By default, searches are not cached.
3159 For more examples of using these attributes, see
3160 L<DBIx::Class::Manual::Cookbook>.
3166 =item Value: \@from_clause
3170 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3171 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3174 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3176 C<join> will usually do what you need and it is strongly recommended that you
3177 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3178 And we really do mean "cannot", not just tried and failed. Attempting to use
3179 this because you're having problems with C<join> is like trying to use x86
3180 ASM because you've got a syntax error in your C. Trust us on this.
3182 Now, if you're still really, really sure you need to use this (and if you're
3183 not 100% sure, ask the mailing list first), here's an explanation of how this
3186 The syntax is as follows -
3189 { <alias1> => <table1> },
3191 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3192 [], # nested JOIN (optional)
3193 { <table1.column1> => <table2.column2>, ... (more conditions) },
3195 # More of the above [ ] may follow for additional joins
3202 ON <table1.column1> = <table2.column2>
3203 <more joins may follow>
3205 An easy way to follow the examples below is to remember the following:
3207 Anything inside "[]" is a JOIN
3208 Anything inside "{}" is a condition for the enclosing JOIN
3210 The following examples utilize a "person" table in a family tree application.
3211 In order to express parent->child relationships, this table is self-joined:
3213 # Person->belongs_to('father' => 'Person');
3214 # Person->belongs_to('mother' => 'Person');
3216 C<from> can be used to nest joins. Here we return all children with a father,
3217 then search against all mothers of those children:
3219 $rs = $schema->resultset('Person')->search(
3222 alias => 'mother', # alias columns in accordance with "from"
3224 { mother => 'person' },
3227 { child => 'person' },
3229 { father => 'person' },
3230 { 'father.person_id' => 'child.father_id' }
3233 { 'mother.person_id' => 'child.mother_id' }
3240 # SELECT mother.* FROM person mother
3243 # JOIN person father
3244 # ON ( father.person_id = child.father_id )
3246 # ON ( mother.person_id = child.mother_id )
3248 The type of any join can be controlled manually. To search against only people
3249 with a father in the person table, we could explicitly use C<INNER JOIN>:
3251 $rs = $schema->resultset('Person')->search(
3254 alias => 'child', # alias columns in accordance with "from"
3256 { child => 'person' },
3258 { father => 'person', -join_type => 'inner' },
3259 { 'father.id' => 'child.father_id' }
3266 # SELECT child.* FROM person child
3267 # INNER JOIN person father ON child.father_id = father.id
3269 If you need to express really complex joins or you need a subselect, you
3270 can supply literal SQL to C<from> via a scalar reference. In this case
3271 the contents of the scalar will replace the table name asscoiated with the
3274 WARNING: This technique might very well not work as expected on chained
3275 searches - you have been warned.
3277 # Assuming the Event resultsource is defined as:
3279 MySchema::Event->add_columns (
3282 is_auto_increment => 1,
3291 MySchema::Event->set_primary_key ('sequence');
3293 # This will get back the latest event for every location. The column
3294 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3295 # combo to limit the resultset
3297 $rs = $schema->resultset('Event');
3298 $table = $rs->result_source->name;
3299 $latest = $rs->search (
3302 (SELECT e1.* FROM $table e1
3304 ON e1.location = e2.location
3305 AND e1.sequence < e2.sequence
3306 WHERE e2.sequence is NULL
3311 # Equivalent SQL (with the DBIC chunks added):
3313 SELECT me.sequence, me.location, me.type FROM
3314 (SELECT e1.* FROM events e1
3316 ON e1.location = e2.location
3317 AND e1.sequence < e2.sequence
3318 WHERE e2.sequence is NULL
3325 =item Value: ( 'update' | 'shared' )
3329 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT