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 $_[0] eq 'HASH' ? shift : {@_};
1980 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
1983 return $self->new_result($hash);
1990 =item Arguments: \%vals
1992 =item Return Value: a L<DBIx::Class::Row> $object
1996 Attempt to create a single new row or a row with multiple related rows
1997 in the table represented by the resultset (and related tables). This
1998 will not check for duplicate rows before inserting, use
1999 L</find_or_create> to do that.
2001 To create one row for this resultset, pass a hashref of key/value
2002 pairs representing the columns of the table and the values you wish to
2003 store. If the appropriate relationships are set up, foreign key fields
2004 can also be passed an object representing the foreign row, and the
2005 value will be set to its primary key.
2007 To create related objects, pass a hashref for the value if the related
2008 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
2009 and use the name of the relationship as the key. (NOT the name of the field,
2010 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
2011 of hashrefs containing the data for each of the rows to create in the foreign
2012 tables, again using the relationship name as the key.
2014 Instead of hashrefs of plain related data (key/value pairs), you may
2015 also pass new or inserted objects. New objects (not inserted yet, see
2016 L</new>), will be inserted into their appropriate tables.
2018 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
2020 Example of creating a new row.
2022 $person_rs->create({
2023 name=>"Some Person",
2024 email=>"somebody@someplace.com"
2027 Example of creating a new row and also creating rows in a related C<has_many>
2028 or C<has_one> resultset. Note Arrayref.
2031 { artistid => 4, name => 'Manufactured Crap', cds => [
2032 { title => 'My First CD', year => 2006 },
2033 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
2038 Example of creating a new row and also creating a row in a related
2039 C<belongs_to>resultset. Note Hashref.
2042 title=>"Music for Silly Walks",
2045 name=>"Silly Musician",
2052 my ($self, $attrs) = @_;
2053 $self->throw_exception( "create needs a hashref" )
2054 unless ref $attrs eq 'HASH';
2055 return $self->new_result($attrs)->insert;
2058 =head2 find_or_create
2062 =item Arguments: \%vals, \%attrs?
2064 =item Return Value: $rowobject
2068 $cd->cd_to_producer->find_or_create({ producer => $producer },
2069 { key => 'primary });
2071 Tries to find a record based on its primary key or unique constraints; if none
2072 is found, creates one and returns that instead.
2074 my $cd = $schema->resultset('CD')->find_or_create({
2076 artist => 'Massive Attack',
2077 title => 'Mezzanine',
2081 Also takes an optional C<key> attribute, to search by a specific key or unique
2082 constraint. For example:
2084 my $cd = $schema->resultset('CD')->find_or_create(
2086 artist => 'Massive Attack',
2087 title => 'Mezzanine',
2089 { key => 'cd_artist_title' }
2092 B<Note>: Because find_or_create() reads from the database and then
2093 possibly inserts based on the result, this method is subject to a race
2094 condition. Another process could create a record in the table after
2095 the find has completed and before the create has started. To avoid
2096 this problem, use find_or_create() inside a transaction.
2098 B<Note>: C<find_or_create> is probably not what you want when creating
2099 a new row in a table that uses primary keys supplied by the
2100 database. Passing in a primary key column with a value of I<undef>
2101 will cause L</find> to attempt to search for a row with a value of
2104 See also L</find> and L</update_or_create>. For information on how to declare
2105 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2109 sub find_or_create {
2111 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2112 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2113 if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
2116 return $self->create($hash);
2119 =head2 update_or_create
2123 =item Arguments: \%col_values, { key => $unique_constraint }?
2125 =item Return Value: $rowobject
2129 $resultset->update_or_create({ col => $val, ... });
2131 First, searches for an existing row matching one of the unique constraints
2132 (including the primary key) on the source of this resultset. If a row is
2133 found, updates it with the other given column values. Otherwise, creates a new
2136 Takes an optional C<key> attribute to search on a specific unique constraint.
2139 # In your application
2140 my $cd = $schema->resultset('CD')->update_or_create(
2142 artist => 'Massive Attack',
2143 title => 'Mezzanine',
2146 { key => 'cd_artist_title' }
2149 $cd->cd_to_producer->update_or_create({
2150 producer => $producer,
2157 If no C<key> is specified, it searches on all unique constraints defined on the
2158 source, including the primary key.
2160 If the C<key> is specified as C<primary>, it searches only on the primary key.
2162 See also L</find> and L</find_or_create>. For information on how to declare
2163 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2165 B<Note>: C<update_or_create> is probably not what you want when
2166 looking for a row in a table that uses primary keys supplied by the
2167 database, unless you actually have a key value. Passing in a primary
2168 key column with a value of I<undef> will cause L</find> to attempt to
2169 search for a row with a value of I<NULL>.
2173 sub update_or_create {
2175 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2176 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2178 my $row = $self->find($cond, $attrs);
2180 $row->update($cond);
2184 return $self->create($cond);
2187 =head2 update_or_new
2191 =item Arguments: \%col_values, { key => $unique_constraint }?
2193 =item Return Value: $rowobject
2197 $resultset->update_or_new({ col => $val, ... });
2199 First, searches for an existing row matching one of the unique constraints
2200 (including the primary key) on the source of this resultset. If a row is
2201 found, updates it with the other given column values. Otherwise, instantiate
2202 a new result object and return it. The object will not be saved into your storage
2203 until you call L<DBIx::Class::Row/insert> on it.
2205 Takes an optional C<key> attribute to search on a specific unique constraint.
2208 # In your application
2209 my $cd = $schema->resultset('CD')->update_or_new(
2211 artist => 'Massive Attack',
2212 title => 'Mezzanine',
2215 { key => 'cd_artist_title' }
2218 if ($cd->in_storage) {
2219 # the cd was updated
2222 # the cd is not yet in the database, let's insert it
2226 See also L</find>, L</find_or_create> and L<find_or_new>.
2232 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2233 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2235 my $row = $self->find( $cond, $attrs );
2236 if ( defined $row ) {
2237 $row->update($cond);
2241 return $self->new_result($cond);
2248 =item Arguments: none
2250 =item Return Value: \@cache_objects?
2254 Gets the contents of the cache for the resultset, if the cache is set.
2256 The cache is populated either by using the L</prefetch> attribute to
2257 L</search> or by calling L</set_cache>.
2269 =item Arguments: \@cache_objects
2271 =item Return Value: \@cache_objects
2275 Sets the contents of the cache for the resultset. Expects an arrayref
2276 of objects of the same class as those produced by the resultset. Note that
2277 if the cache is set the resultset will return the cached objects rather
2278 than re-querying the database even if the cache attr is not set.
2280 The contents of the cache can also be populated by using the
2281 L</prefetch> attribute to L</search>.
2286 my ( $self, $data ) = @_;
2287 $self->throw_exception("set_cache requires an arrayref")
2288 if defined($data) && (ref $data ne 'ARRAY');
2289 $self->{all_cache} = $data;
2296 =item Arguments: none
2298 =item Return Value: []
2302 Clears the cache for the resultset.
2307 shift->set_cache(undef);
2310 =head2 related_resultset
2314 =item Arguments: $relationship_name
2316 =item Return Value: $resultset
2320 Returns a related resultset for the supplied relationship name.
2322 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2326 sub related_resultset {
2327 my ($self, $rel) = @_;
2329 $self->{related_resultsets} ||= {};
2330 return $self->{related_resultsets}{$rel} ||= do {
2331 my $rel_obj = $self->result_source->relationship_info($rel);
2333 $self->throw_exception(
2334 "search_related: result source '" . $self->result_source->source_name .
2335 "' has no such relationship $rel")
2338 my ($from,$seen) = $self->_resolve_from($rel);
2340 my $join_count = $seen->{$rel};
2341 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2343 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2344 my %attrs = %{$self->{attrs}||{}};
2345 delete @attrs{qw(result_class alias)};
2349 if (my $cache = $self->get_cache) {
2350 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2351 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2356 my $rel_source = $self->result_source->related_source($rel);
2360 # The reason we do this now instead of passing the alias to the
2361 # search_rs below is that if you wrap/overload resultset on the
2362 # source you need to know what alias it's -going- to have for things
2363 # to work sanely (e.g. RestrictWithObject wants to be able to add
2364 # extra query restrictions, and these may need to be $alias.)
2366 my $attrs = $rel_source->resultset_attributes;
2367 local $attrs->{alias} = $alias;
2369 $rel_source->resultset
2377 where => $self->{cond},
2382 $new->set_cache($new_cache) if $new_cache;
2387 =head2 current_source_alias
2391 =item Arguments: none
2393 =item Return Value: $source_alias
2397 Returns the current table alias for the result source this resultset is built
2398 on, that will be used in the SQL query. Usually it is C<me>.
2400 Currently the source alias that refers to the result set returned by a
2401 L</search>/L</find> family method depends on how you got to the resultset: it's
2402 C<me> by default, but eg. L</search_related> aliases it to the related result
2403 source name (and keeps C<me> referring to the original result set). The long
2404 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2405 (and make this method unnecessary).
2407 Thus it's currently necessary to use this method in predefined queries (see
2408 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2409 source alias of the current result set:
2411 # in a result set class
2413 my ($self, $user) = @_;
2415 my $me = $self->current_source_alias;
2417 return $self->search(
2418 "$me.modified" => $user->id,
2424 sub current_source_alias {
2427 return ($self->{attrs} || {})->{alias} || 'me';
2430 # This code is called by search_related, and makes sure there
2431 # is clear separation between the joins before, during, and
2432 # after the relationship. This information is needed later
2433 # in order to properly resolve prefetch aliases (any alias
2434 # with a relation_chain_depth less than the depth of the
2435 # current prefetch is not considered)
2437 my ($self, $extra_join) = @_;
2438 my $source = $self->result_source;
2439 my $attrs = $self->{attrs};
2441 my $from = $attrs->{from}
2442 || [ { $attrs->{alias} => $source->from } ];
2444 my $seen = { %{$attrs->{seen_join} || {} } };
2446 # we need to take the prefetch the attrs into account before we
2447 # ->_resolve_join as otherwise they get lost - captainL
2448 my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
2450 push @$from, $source->_resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
2452 ++$seen->{-relation_chain_depth};
2454 push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
2456 ++$seen->{-relation_chain_depth};
2458 return ($from,$seen);
2461 # too many times we have to do $attrs = { %{$self->_resolved_attrs} }
2462 sub _resolved_attrs_copy {
2464 return { %{$self->_resolved_attrs (@_)} };
2467 sub _resolved_attrs {
2469 return $self->{_attrs} if $self->{_attrs};
2471 my $attrs = { %{ $self->{attrs} || {} } };
2472 my $source = $self->result_source;
2473 my $alias = $attrs->{alias};
2475 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2478 # build columns (as long as select isn't set) into a set of as/select hashes
2479 unless ( $attrs->{select} ) {
2481 ( ref($_) eq 'HASH' )
2485 /^\Q${alias}.\E(.+)$/
2496 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2498 # add the additional columns on
2499 foreach ( 'include_columns', '+columns' ) {
2500 push @colbits, map {
2501 ( ref($_) eq 'HASH' )
2503 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2504 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2507 # start with initial select items
2508 if ( $attrs->{select} ) {
2510 ( ref $attrs->{select} eq 'ARRAY' )
2511 ? [ @{ $attrs->{select} } ]
2512 : [ $attrs->{select} ];
2516 ref $attrs->{as} eq 'ARRAY'
2517 ? [ @{ $attrs->{as} } ]
2520 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2525 # otherwise we intialise select & as to empty
2526 $attrs->{select} = [];
2530 # now add colbits to select/as
2531 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2532 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2535 if ( $adds = delete $attrs->{'+select'} ) {
2536 $adds = [$adds] unless ref $adds eq 'ARRAY';
2538 @{ $attrs->{select} },
2539 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2542 if ( $adds = delete $attrs->{'+as'} ) {
2543 $adds = [$adds] unless ref $adds eq 'ARRAY';
2544 push( @{ $attrs->{as} }, @$adds );
2547 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2549 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2550 my $join = delete $attrs->{join} || {};
2552 if ( defined $attrs->{prefetch} ) {
2553 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2557 $attrs->{from} = # have to copy here to avoid corrupting the original
2559 @{ $attrs->{from} },
2560 $source->_resolve_join(
2561 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2567 if ( $attrs->{order_by} ) {
2568 $attrs->{order_by} = (
2569 ref( $attrs->{order_by} ) eq 'ARRAY'
2570 ? [ @{ $attrs->{order_by} } ]
2571 : [ $attrs->{order_by} ]
2575 $attrs->{order_by} = [];
2578 my $collapse = $attrs->{collapse} || {};
2579 if ( my $prefetch = delete $attrs->{prefetch} ) {
2580 $prefetch = $self->_merge_attr( {}, $prefetch );
2582 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2584 # bring joins back to level of current class
2585 my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
2587 $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
2588 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2589 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2591 push( @{ $attrs->{order_by} }, @pre_order );
2594 if (delete $attrs->{distinct}) {
2595 $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
2598 $attrs->{collapse} = $collapse;
2600 if ( $attrs->{page} and not defined $attrs->{offset} ) {
2601 $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2604 return $self->{_attrs} = $attrs;
2607 sub _joinpath_aliases {
2608 my ($self, $fromspec, $seen) = @_;
2611 return $paths unless ref $fromspec eq 'ARRAY';
2613 for my $j (@$fromspec) {
2615 next if ref $j ne 'ARRAY';
2616 next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
2619 $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
2620 push @{$p->{-join_aliases} }, $j->[0]{-join_alias};
2627 my ($self, $attr) = @_;
2629 if (ref $attr eq 'HASH') {
2630 return $self->_rollout_hash($attr);
2631 } elsif (ref $attr eq 'ARRAY') {
2632 return $self->_rollout_array($attr);
2638 sub _rollout_array {
2639 my ($self, $attr) = @_;
2642 foreach my $element (@{$attr}) {
2643 if (ref $element eq 'HASH') {
2644 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2645 } elsif (ref $element eq 'ARRAY') {
2646 # XXX - should probably recurse here
2647 push( @rolled_array, @{$self->_rollout_array($element)} );
2649 push( @rolled_array, $element );
2652 return \@rolled_array;
2656 my ($self, $attr) = @_;
2659 foreach my $key (keys %{$attr}) {
2660 push( @rolled_array, { $key => $attr->{$key} } );
2662 return \@rolled_array;
2665 sub _calculate_score {
2666 my ($self, $a, $b) = @_;
2668 if (ref $b eq 'HASH') {
2669 my ($b_key) = keys %{$b};
2670 if (ref $a eq 'HASH') {
2671 my ($a_key) = keys %{$a};
2672 if ($a_key eq $b_key) {
2673 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2678 return ($a eq $b_key) ? 1 : 0;
2681 if (ref $a eq 'HASH') {
2682 my ($a_key) = keys %{$a};
2683 return ($b eq $a_key) ? 1 : 0;
2685 return ($b eq $a) ? 1 : 0;
2691 my ($self, $orig, $import) = @_;
2693 return $import unless defined($orig);
2694 return $orig unless defined($import);
2696 $orig = $self->_rollout_attr($orig);
2697 $import = $self->_rollout_attr($import);
2700 foreach my $import_element ( @{$import} ) {
2701 # find best candidate from $orig to merge $b_element into
2702 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2703 foreach my $orig_element ( @{$orig} ) {
2704 my $score = $self->_calculate_score( $orig_element, $import_element );
2705 if ($score > $best_candidate->{score}) {
2706 $best_candidate->{position} = $position;
2707 $best_candidate->{score} = $score;
2711 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2713 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2714 push( @{$orig}, $import_element );
2716 my $orig_best = $orig->[$best_candidate->{position}];
2717 # merge orig_best and b_element together and replace original with merged
2718 if (ref $orig_best ne 'HASH') {
2719 $orig->[$best_candidate->{position}] = $import_element;
2720 } elsif (ref $import_element eq 'HASH') {
2721 my ($key) = keys %{$orig_best};
2722 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2725 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2735 $self->_source_handle($_[0]->handle);
2737 $self->_source_handle->resolve;
2741 =head2 throw_exception
2743 See L<DBIx::Class::Schema/throw_exception> for details.
2747 sub throw_exception {
2749 if (ref $self && $self->_source_handle->schema) {
2750 $self->_source_handle->schema->throw_exception(@_)
2757 # XXX: FIXME: Attributes docs need clearing up
2761 Attributes are used to refine a ResultSet in various ways when
2762 searching for data. They can be passed to any method which takes an
2763 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2766 These are in no particular order:
2772 =item Value: ( $order_by | \@order_by | \%order_by )
2776 Which column(s) to order the results by. If a single column name, or
2777 an arrayref of names is supplied, the argument is passed through
2778 directly to SQL. The hashref syntax allows for connection-agnostic
2779 specification of ordering direction:
2781 For descending order:
2783 order_by => { -desc => [qw/col1 col2 col3/] }
2785 For explicit ascending order:
2787 order_by => { -asc => 'col' }
2789 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2790 supported, although you are strongly encouraged to use the hashref
2791 syntax as outlined above.
2797 =item Value: \@columns
2801 Shortcut to request a particular set of columns to be retrieved. Each
2802 column spec may be a string (a table column name), or a hash (in which
2803 case the key is the C<as> value, and the value is used as the C<select>
2804 expression). Adds C<me.> onto the start of any column without a C<.> in
2805 it and sets C<select> from that, then auto-populates C<as> from
2806 C<select> as normal. (You may also use the C<cols> attribute, as in
2807 earlier versions of DBIC.)
2813 =item Value: \@columns
2817 Indicates additional columns to be selected from storage. Works the same
2818 as L</columns> but adds columns to the selection. (You may also use the
2819 C<include_columns> attribute, as in earlier versions of DBIC). For
2822 $schema->resultset('CD')->search(undef, {
2823 '+columns' => ['artist.name'],
2827 would return all CDs and include a 'name' column to the information
2828 passed to object inflation. Note that the 'artist' is the name of the
2829 column (or relationship) accessor, and 'name' is the name of the column
2830 accessor in the related table.
2832 =head2 include_columns
2836 =item Value: \@columns
2840 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2846 =item Value: \@select_columns
2850 Indicates which columns should be selected from the storage. You can use
2851 column names, or in the case of RDBMS back ends, function or stored procedure
2854 $rs = $schema->resultset('Employee')->search(undef, {
2857 { count => 'employeeid' },
2862 When you use function/stored procedure names and do not supply an C<as>
2863 attribute, the column names returned are storage-dependent. E.g. MySQL would
2864 return a column named C<count(employeeid)> in the above example.
2870 Indicates additional columns to be selected from storage. Works the same as
2871 L</select> but adds columns to the selection.
2879 Indicates additional column names for those added via L</+select>. See L</as>.
2887 =item Value: \@inflation_names
2891 Indicates column names for object inflation. That is, C<as>
2892 indicates the name that the column can be accessed as via the
2893 C<get_column> method (or via the object accessor, B<if one already
2894 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2896 The C<as> attribute is used in conjunction with C<select>,
2897 usually when C<select> contains one or more function or stored
2900 $rs = $schema->resultset('Employee')->search(undef, {
2903 { count => 'employeeid' }
2905 as => ['name', 'employee_count'],
2908 my $employee = $rs->first(); # get the first Employee
2910 If the object against which the search is performed already has an accessor
2911 matching a column name specified in C<as>, the value can be retrieved using
2912 the accessor as normal:
2914 my $name = $employee->name();
2916 If on the other hand an accessor does not exist in the object, you need to
2917 use C<get_column> instead:
2919 my $employee_count = $employee->get_column('employee_count');
2921 You can create your own accessors if required - see
2922 L<DBIx::Class::Manual::Cookbook> for details.
2924 Please note: This will NOT insert an C<AS employee_count> into the SQL
2925 statement produced, it is used for internal access only. Thus
2926 attempting to use the accessor in an C<order_by> clause or similar
2927 will fail miserably.
2929 To get around this limitation, you can supply literal SQL to your
2930 C<select> attibute that contains the C<AS alias> text, eg:
2932 select => [\'myfield AS alias']
2938 =item Value: ($rel_name | \@rel_names | \%rel_names)
2942 Contains a list of relationships that should be joined for this query. For
2945 # Get CDs by Nine Inch Nails
2946 my $rs = $schema->resultset('CD')->search(
2947 { 'artist.name' => 'Nine Inch Nails' },
2948 { join => 'artist' }
2951 Can also contain a hash reference to refer to the other relation's relations.
2954 package MyApp::Schema::Track;
2955 use base qw/DBIx::Class/;
2956 __PACKAGE__->table('track');
2957 __PACKAGE__->add_columns(qw/trackid cd position title/);
2958 __PACKAGE__->set_primary_key('trackid');
2959 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2962 # In your application
2963 my $rs = $schema->resultset('Artist')->search(
2964 { 'track.title' => 'Teardrop' },
2966 join => { cd => 'track' },
2967 order_by => 'artist.name',
2971 You need to use the relationship (not the table) name in conditions,
2972 because they are aliased as such. The current table is aliased as "me", so
2973 you need to use me.column_name in order to avoid ambiguity. For example:
2975 # Get CDs from 1984 with a 'Foo' track
2976 my $rs = $schema->resultset('CD')->search(
2979 'tracks.name' => 'Foo'
2981 { join => 'tracks' }
2984 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2985 similarly for a third time). For e.g.
2987 my $rs = $schema->resultset('Artist')->search({
2988 'cds.title' => 'Down to Earth',
2989 'cds_2.title' => 'Popular',
2991 join => [ qw/cds cds/ ],
2994 will return a set of all artists that have both a cd with title 'Down
2995 to Earth' and a cd with title 'Popular'.
2997 If you want to fetch related objects from other tables as well, see C<prefetch>
3000 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
3006 =item Value: ($rel_name | \@rel_names | \%rel_names)
3010 Contains one or more relationships that should be fetched along with
3011 the main query (when they are accessed afterwards the data will
3012 already be available, without extra queries to the database). This is
3013 useful for when you know you will need the related objects, because it
3014 saves at least one query:
3016 my $rs = $schema->resultset('Tag')->search(
3025 The initial search results in SQL like the following:
3027 SELECT tag.*, cd.*, artist.* FROM tag
3028 JOIN cd ON tag.cd = cd.cdid
3029 JOIN artist ON cd.artist = artist.artistid
3031 L<DBIx::Class> has no need to go back to the database when we access the
3032 C<cd> or C<artist> relationships, which saves us two SQL statements in this
3035 Simple prefetches will be joined automatically, so there is no need
3036 for a C<join> attribute in the above search.
3038 C<prefetch> can be used with the following relationship types: C<belongs_to>,
3039 C<has_one> (or if you're using C<add_relationship>, any relationship declared
3040 with an accessor type of 'single' or 'filter'). A more complex example that
3041 prefetches an artists cds, the tracks on those cds, and the tags associted
3042 with that artist is given below (assuming many-to-many from artists to tags):
3044 my $rs = $schema->resultset('Artist')->search(
3048 { cds => 'tracks' },
3049 { artist_tags => 'tags' }
3055 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
3056 attributes will be ignored.
3066 Makes the resultset paged and specifies the page to retrieve. Effectively
3067 identical to creating a non-pages resultset and then calling ->page($page)
3070 If L<rows> attribute is not specified it defualts to 10 rows per page.
3072 When you have a paged resultset, L</count> will only return the number
3073 of rows in the page. To get the total, use the L</pager> and call
3074 C<total_entries> on it.
3084 Specifes the maximum number of rows for direct retrieval or the number of
3085 rows per page if the page attribute or method is used.
3091 =item Value: $offset
3095 Specifies the (zero-based) row number for the first row to be returned, or the
3096 of the first row of the first page if paging is used.
3102 =item Value: \@columns
3106 A arrayref of columns to group by. Can include columns of joined tables.
3108 group_by => [qw/ column1 column2 ... /]
3114 =item Value: $condition
3118 HAVING is a select statement attribute that is applied between GROUP BY and
3119 ORDER BY. It is applied to the after the grouping calculations have been
3122 having => { 'count(employee)' => { '>=', 100 } }
3128 =item Value: (0 | 1)
3132 Set to 1 to group by all columns.
3138 Adds to the WHERE clause.
3140 # only return rows WHERE deleted IS NULL for all searches
3141 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3143 Can be overridden by passing C<{ where => undef }> as an attribute
3150 Set to 1 to cache search results. This prevents extra SQL queries if you
3151 revisit rows in your ResultSet:
3153 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3155 while( my $artist = $resultset->next ) {
3159 $rs->first; # without cache, this would issue a query
3161 By default, searches are not cached.
3163 For more examples of using these attributes, see
3164 L<DBIx::Class::Manual::Cookbook>.
3170 =item Value: \@from_clause
3174 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3175 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3178 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3180 C<join> will usually do what you need and it is strongly recommended that you
3181 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3182 And we really do mean "cannot", not just tried and failed. Attempting to use
3183 this because you're having problems with C<join> is like trying to use x86
3184 ASM because you've got a syntax error in your C. Trust us on this.
3186 Now, if you're still really, really sure you need to use this (and if you're
3187 not 100% sure, ask the mailing list first), here's an explanation of how this
3190 The syntax is as follows -
3193 { <alias1> => <table1> },
3195 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3196 [], # nested JOIN (optional)
3197 { <table1.column1> => <table2.column2>, ... (more conditions) },
3199 # More of the above [ ] may follow for additional joins
3206 ON <table1.column1> = <table2.column2>
3207 <more joins may follow>
3209 An easy way to follow the examples below is to remember the following:
3211 Anything inside "[]" is a JOIN
3212 Anything inside "{}" is a condition for the enclosing JOIN
3214 The following examples utilize a "person" table in a family tree application.
3215 In order to express parent->child relationships, this table is self-joined:
3217 # Person->belongs_to('father' => 'Person');
3218 # Person->belongs_to('mother' => 'Person');
3220 C<from> can be used to nest joins. Here we return all children with a father,
3221 then search against all mothers of those children:
3223 $rs = $schema->resultset('Person')->search(
3226 alias => 'mother', # alias columns in accordance with "from"
3228 { mother => 'person' },
3231 { child => 'person' },
3233 { father => 'person' },
3234 { 'father.person_id' => 'child.father_id' }
3237 { 'mother.person_id' => 'child.mother_id' }
3244 # SELECT mother.* FROM person mother
3247 # JOIN person father
3248 # ON ( father.person_id = child.father_id )
3250 # ON ( mother.person_id = child.mother_id )
3252 The type of any join can be controlled manually. To search against only people
3253 with a father in the person table, we could explicitly use C<INNER JOIN>:
3255 $rs = $schema->resultset('Person')->search(
3258 alias => 'child', # alias columns in accordance with "from"
3260 { child => 'person' },
3262 { father => 'person', -join_type => 'inner' },
3263 { 'father.id' => 'child.father_id' }
3270 # SELECT child.* FROM person child
3271 # INNER JOIN person father ON child.father_id = father.id
3273 If you need to express really complex joins or you need a subselect, you
3274 can supply literal SQL to C<from> via a scalar reference. In this case
3275 the contents of the scalar will replace the table name asscoiated with the
3278 WARNING: This technique might very well not work as expected on chained
3279 searches - you have been warned.
3281 # Assuming the Event resultsource is defined as:
3283 MySchema::Event->add_columns (
3286 is_auto_increment => 1,
3295 MySchema::Event->set_primary_key ('sequence');
3297 # This will get back the latest event for every location. The column
3298 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3299 # combo to limit the resultset
3301 $rs = $schema->resultset('Event');
3302 $table = $rs->result_source->name;
3303 $latest = $rs->search (
3306 (SELECT e1.* FROM $table e1
3308 ON e1.location = e2.location
3309 AND e1.sequence < e2.sequence
3310 WHERE e2.sequence is NULL
3315 # Equivalent SQL (with the DBIC chunks added):
3317 SELECT me.sequence, me.location, me.type FROM
3318 (SELECT e1.* FROM events e1
3320 ON e1.location = e2.location
3321 AND e1.sequence < e2.sequence
3322 WHERE e2.sequence is NULL
3329 =item Value: ( 'update' | 'shared' )
3333 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT