1 package DBIx::Class::ResultSet;
9 use Carp::Clan qw/^DBIx::Class/;
12 use DBIx::Class::ResultSetColumn;
13 use DBIx::Class::ResultSourceHandle;
16 use base qw/DBIx::Class/;
18 __PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
22 DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
26 my $users_rs = $schema->resultset('User');
27 my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
28 my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
32 A ResultSet is an object which stores a set of conditions representing
33 a query. It is the backbone of DBIx::Class (i.e. the really
34 important/useful bit).
36 No SQL is executed on the database when a ResultSet is created, it
37 just stores all the conditions needed to create the query.
39 A basic ResultSet representing the data of an entire table is returned
40 by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
41 L<Source|DBIx::Class::Manual::Glossary/Source> name.
43 my $users_rs = $schema->resultset('User');
45 A new ResultSet is returned from calling L</search> on an existing
46 ResultSet. The new one will contain all the conditions of the
47 original, plus any new conditions added in the C<search> call.
49 A ResultSet is also an iterator. L</next> is used to return all the
50 L<DBIx::Class::Row>s the ResultSet represents.
52 The query that the ResultSet represents is B<only> executed against
53 the database when these methods are called:
73 =head2 Chaining resultsets
75 Let's say you've got a query that needs to be run to return some data
76 to the user. But, you have an authorization system in place that
77 prevents certain users from seeing certain information. So, you want
78 to construct the basic query in one method, but add constraints to it in
83 my $request = $self->get_request; # Get a request object somehow.
84 my $schema = $self->get_schema; # Get the DBIC schema object somehow.
86 my $cd_rs = $schema->resultset('CD')->search({
87 title => $request->param('title'),
88 year => $request->param('year'),
91 $self->apply_security_policy( $cd_rs );
96 sub apply_security_policy {
105 =head3 Resolving conditions and attributes
107 When a resultset is chained from another resultset, conditions and
108 attributes with the same keys need resolving.
110 L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
111 into the existing ones from the original resultset.
113 The L</where>, L</having> attribute, and any search conditions are
114 merged with an SQL C<AND> to the existing condition from the original
117 All other attributes are overridden by any new ones supplied in the
120 =head2 Multiple queries
122 Since a resultset just defines a query, you can do all sorts of
123 things with it with the same object.
125 # Don't hit the DB yet.
126 my $cd_rs = $schema->resultset('CD')->search({
127 title => 'something',
131 # Each of these hits the DB individually.
132 my $count = $cd_rs->count;
133 my $most_recent = $cd_rs->get_column('date_released')->max();
134 my @records = $cd_rs->all;
136 And it's not just limited to SELECT statements.
142 $cd_rs->create({ artist => 'Fred' });
144 Which is the same as:
146 $schema->resultset('CD')->create({
147 title => 'something',
152 See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
156 If a resultset is used in a numeric context it returns the L</count>.
157 However, if it is used in a booleand context it is always true. So if
158 you want to check if a resultset has any results use C<if $rs != 0>.
159 C<if $rs> will always be true.
167 =item Arguments: $source, \%$attrs
169 =item Return Value: $rs
173 The resultset constructor. Takes a source object (usually a
174 L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
175 L</ATTRIBUTES> below). Does not perform any queries -- these are
176 executed as needed by the other methods.
178 Generally you won't need to construct a resultset manually. You'll
179 automatically get one from e.g. a L</search> called in scalar context:
181 my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
183 IMPORTANT: If called on an object, proxies to new_result instead so
185 my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
187 will return a CD object, not a ResultSet.
193 return $class->new_result(@_) if ref $class;
195 my ($source, $attrs) = @_;
196 $source = $source->handle
197 unless $source->isa('DBIx::Class::ResultSourceHandle');
198 $attrs = { %{$attrs||{}} };
200 if ($attrs->{page}) {
201 $attrs->{rows} ||= 10;
204 $attrs->{alias} ||= 'me';
206 # Creation of {} and bless separated to mitigate RH perl bug
207 # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
209 _source_handle => $source,
210 cond => $attrs->{where},
219 $attrs->{result_class} || $source->resolve->result_class
229 =item Arguments: $cond, \%attrs?
231 =item Return Value: $resultset (scalar context), @row_objs (list context)
235 my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
236 my $new_rs = $cd_rs->search({ year => 2005 });
238 my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
239 # year = 2005 OR year = 2004
241 If you need to pass in additional attributes but no additional condition,
242 call it as C<search(undef, \%attrs)>.
244 # "SELECT name, artistid FROM $artist_table"
245 my @all_artists = $schema->resultset('Artist')->search(undef, {
246 columns => [qw/name artistid/],
249 For a list of attributes that can be passed to C<search>, see
250 L</ATTRIBUTES>. For more examples of using this function, see
251 L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
252 documentation for the first argument, see L<SQL::Abstract>.
254 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
260 my $rs = $self->search_rs( @_ );
261 return (wantarray ? $rs->all : $rs);
268 =item Arguments: $cond, \%attrs?
270 =item Return Value: $resultset
274 This method does the same exact thing as search() except it will
275 always return a resultset, even in list context.
282 # Special-case handling for (undef, undef).
283 if ( @_ == 2 && !defined $_[1] && !defined $_[0] ) {
288 $attrs = pop(@_) if @_ > 1 and ref $_[$#_] eq 'HASH';
289 my $our_attrs = { %{$self->{attrs}} };
290 my $having = delete $our_attrs->{having};
291 my $where = delete $our_attrs->{where};
295 my %safe = (alias => 1, cache => 1);
298 (@_ && defined($_[0])) # @_ == () or (undef)
300 (keys %$attrs # empty attrs or only 'safe' attrs
301 && List::Util::first { !$safe{$_} } keys %$attrs)
303 # no search, effectively just a clone
304 $rows = $self->get_cache;
307 my $new_attrs = { %{$our_attrs}, %{$attrs} };
309 # merge new attrs into inherited
310 foreach my $key (qw/join prefetch +select +as/) {
311 next unless exists $attrs->{$key};
312 $new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
317 (@_ == 1 || ref $_[0] eq "HASH")
319 (ref $_[0] eq 'HASH')
321 (keys %{ $_[0] } > 0)
329 ? $self->throw_exception("Odd number of arguments to search")
336 if (defined $where) {
337 $new_attrs->{where} = (
338 defined $new_attrs->{where}
341 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
342 } $where, $new_attrs->{where}
349 $new_attrs->{where} = (
350 defined $new_attrs->{where}
353 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
354 } $cond, $new_attrs->{where}
360 if (defined $having) {
361 $new_attrs->{having} = (
362 defined $new_attrs->{having}
365 ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_
366 } $having, $new_attrs->{having}
372 my $rs = (ref $self)->new($self->result_source, $new_attrs);
374 $rs->set_cache($rows);
379 =head2 search_literal
383 =item Arguments: $sql_fragment, @bind_values
385 =item Return Value: $resultset (scalar context), @row_objs (list context)
389 my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
390 my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
392 Pass a literal chunk of SQL to be added to the conditional part of the
395 CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
396 only be used in that context. C<search_literal> is a convenience method.
397 It is equivalent to calling $schema->search(\[]), but if you want to ensure
398 columns are bound correctly, use C<search>.
400 Example of how to use C<search> instead of C<search_literal>
402 my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
403 my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
406 See L<DBIx::Class::Manual::Cookbook/Searching> and
407 L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
408 require C<search_literal>.
413 my ($self, $sql, @bind) = @_;
415 if ( @bind && ref($bind[-1]) eq 'HASH' ) {
418 return $self->search(\[ $sql, map [ __DUMMY__ => $_ ], @bind ], ($attr || () ));
425 =item Arguments: @values | \%cols, \%attrs?
427 =item Return Value: $row_object | undef
431 Finds a row based on its primary key or unique constraint. For example, to find
432 a row by its primary key:
434 my $cd = $schema->resultset('CD')->find(5);
436 You can also find a row by a specific unique constraint using the C<key>
437 attribute. For example:
439 my $cd = $schema->resultset('CD')->find('Massive Attack', 'Mezzanine', {
440 key => 'cd_artist_title'
443 Additionally, you can specify the columns explicitly by name:
445 my $cd = $schema->resultset('CD')->find(
447 artist => 'Massive Attack',
448 title => 'Mezzanine',
450 { key => 'cd_artist_title' }
453 If the C<key> is specified as C<primary>, it searches only on the primary key.
455 If no C<key> is specified, it searches on all unique constraints defined on the
456 source for which column data is provided, including the primary key.
458 If your table does not have a primary key, you B<must> provide a value for the
459 C<key> attribute matching one of the unique constraints on the source.
461 In addition to C<key>, L</find> recognizes and applies standard
462 L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
464 Note: If your query does not return only one row, a warning is generated:
466 Query returned more than one row
468 See also L</find_or_create> and L</update_or_create>. For information on how to
469 declare unique constraints, see
470 L<DBIx::Class::ResultSource/add_unique_constraint>.
476 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
478 # Default to the primary key, but allow a specific key
479 my @cols = exists $attrs->{key}
480 ? $self->result_source->unique_constraint_columns($attrs->{key})
481 : $self->result_source->primary_columns;
482 $self->throw_exception(
483 "Can't find unless a primary key is defined or unique constraint is specified"
486 # Parse out a hashref from input
488 if (ref $_[0] eq 'HASH') {
489 $input_query = { %{$_[0]} };
491 elsif (@_ == @cols) {
493 @{$input_query}{@cols} = @_;
496 # Compatibility: Allow e.g. find(id => $value)
497 carp "Find by key => value deprecated; please use a hashref instead";
501 my (%related, $info);
503 KEY: foreach my $key (keys %$input_query) {
504 if (ref($input_query->{$key})
505 && ($info = $self->result_source->relationship_info($key))) {
506 my $val = delete $input_query->{$key};
507 next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
508 my $rel_q = $self->result_source->resolve_condition(
509 $info->{cond}, $val, $key
511 die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
512 @related{keys %$rel_q} = values %$rel_q;
515 if (my @keys = keys %related) {
516 @{$input_query}{@keys} = values %related;
520 # Build the final query: Default to the disjunction of the unique queries,
521 # but allow the input query in case the ResultSet defines the query or the
522 # user is abusing find
523 my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
525 if (exists $attrs->{key}) {
526 my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key});
527 my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
528 $query = $self->_add_alias($unique_query, $alias);
531 my @unique_queries = $self->_unique_queries($input_query, $attrs);
532 $query = @unique_queries
533 ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
534 : $self->_add_alias($input_query, $alias);
539 my $rs = $self->search($query, $attrs);
540 if (keys %{$rs->_resolved_attrs->{collapse}}) {
542 carp "Query returned more than one row" if $rs->next;
550 if (keys %{$self->_resolved_attrs->{collapse}}) {
551 my $rs = $self->search($query);
553 carp "Query returned more than one row" if $rs->next;
557 return $self->single($query);
564 # Add the specified alias to the specified query hash. A copy is made so the
565 # original query is not modified.
568 my ($self, $query, $alias) = @_;
570 my %aliased = %$query;
571 foreach my $col (grep { ! m/\./ } keys %aliased) {
572 $aliased{"$alias.$col"} = delete $aliased{$col};
580 # Build a list of queries which satisfy unique constraints.
582 sub _unique_queries {
583 my ($self, $query, $attrs) = @_;
585 my @constraint_names = exists $attrs->{key}
587 : $self->result_source->unique_constraint_names;
589 my $where = $self->_collapse_cond($self->{attrs}{where} || {});
590 my $num_where = scalar keys %$where;
593 foreach my $name (@constraint_names) {
594 my @unique_cols = $self->result_source->unique_constraint_columns($name);
595 my $unique_query = $self->_build_unique_query($query, \@unique_cols);
597 my $num_cols = scalar @unique_cols;
598 my $num_query = scalar keys %$unique_query;
600 my $total = $num_query + $num_where;
601 if ($num_query && ($num_query == $num_cols || $total == $num_cols)) {
602 # The query is either unique on its own or is unique in combination with
603 # the existing where clause
604 push @unique_queries, $unique_query;
608 return @unique_queries;
611 # _build_unique_query
613 # Constrain the specified query hash based on the specified column names.
615 sub _build_unique_query {
616 my ($self, $query, $unique_cols) = @_;
619 map { $_ => $query->{$_} }
620 grep { exists $query->{$_} }
625 =head2 search_related
629 =item Arguments: $rel, $cond, \%attrs?
631 =item Return Value: $new_resultset
635 $new_rs = $cd_rs->search_related('artist', {
639 Searches the specified relationship, optionally specifying a condition and
640 attributes for matching records. See L</ATTRIBUTES> for more information.
645 return shift->related_resultset(shift)->search(@_);
648 =head2 search_related_rs
650 This method works exactly the same as search_related, except that
651 it guarantees a restultset, even in list context.
655 sub search_related_rs {
656 return shift->related_resultset(shift)->search_rs(@_);
663 =item Arguments: none
665 =item Return Value: $cursor
669 Returns a storage-driven cursor to the given resultset. See
670 L<DBIx::Class::Cursor> for more information.
677 my $attrs = { %{$self->_resolved_attrs} };
678 return $self->{cursor}
679 ||= $self->result_source->storage->select($attrs->{from}, $attrs->{select},
680 $attrs->{where},$attrs);
687 =item Arguments: $cond?
689 =item Return Value: $row_object?
693 my $cd = $schema->resultset('CD')->single({ year => 2001 });
695 Inflates the first result without creating a cursor if the resultset has
696 any records in it; if not returns nothing. Used by L</find> as a lean version of
699 While this method can take an optional search condition (just like L</search>)
700 being a fast-code-path it does not recognize search attributes. If you need to
701 add extra joins or similar, call L</search> and then chain-call L</single> on the
702 L<DBIx::Class::ResultSet> returned.
708 As of 0.08100, this method enforces the assumption that the preceeding
709 query returns only one row. If more than one row is returned, you will receive
712 Query returned more than one row
714 In this case, you should be using L</first> or L</find> instead, or if you really
715 know what you are doing, use the L</rows> attribute to explicitly limit the size
723 my ($self, $where) = @_;
725 $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
728 my $attrs = { %{$self->_resolved_attrs} };
730 if (defined $attrs->{where}) {
733 [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
734 $where, delete $attrs->{where} ]
737 $attrs->{where} = $where;
741 # XXX: Disabled since it doesn't infer uniqueness in all cases
742 # unless ($self->_is_unique_query($attrs->{where})) {
743 # carp "Query not guaranteed to return a single row"
744 # . "; please declare your unique constraints or use search instead";
747 my @data = $self->result_source->storage->select_single(
748 $attrs->{from}, $attrs->{select},
749 $attrs->{where}, $attrs
752 return (@data ? ($self->_construct_object(@data))[0] : undef);
757 # Try to determine if the specified query is guaranteed to be unique, based on
758 # the declared unique constraints.
760 sub _is_unique_query {
761 my ($self, $query) = @_;
763 my $collapsed = $self->_collapse_query($query);
764 my $alias = $self->{attrs}{alias};
766 foreach my $name ($self->result_source->unique_constraint_names) {
767 my @unique_cols = map {
769 } $self->result_source->unique_constraint_columns($name);
771 # Count the values for each unique column
772 my %seen = map { $_ => 0 } @unique_cols;
774 foreach my $key (keys %$collapsed) {
775 my $aliased = $key =~ /\./ ? $key : "$alias.$key";
776 next unless exists $seen{$aliased}; # Additional constraints are okay
777 $seen{$aliased} = scalar keys %{ $collapsed->{$key} };
780 # If we get 0 or more than 1 value for a column, it's not necessarily unique
781 return 1 unless grep { $_ != 1 } values %seen;
789 # Recursively collapse the query, accumulating values for each column.
791 sub _collapse_query {
792 my ($self, $query, $collapsed) = @_;
796 if (ref $query eq 'ARRAY') {
797 foreach my $subquery (@$query) {
798 next unless ref $subquery; # -or
799 # warn "ARRAY: " . Dumper $subquery;
800 $collapsed = $self->_collapse_query($subquery, $collapsed);
803 elsif (ref $query eq 'HASH') {
804 if (keys %$query and (keys %$query)[0] eq '-and') {
805 foreach my $subquery (@{$query->{-and}}) {
806 # warn "HASH: " . Dumper $subquery;
807 $collapsed = $self->_collapse_query($subquery, $collapsed);
811 # warn "LEAF: " . Dumper $query;
812 foreach my $col (keys %$query) {
813 my $value = $query->{$col};
814 $collapsed->{$col}{$value}++;
826 =item Arguments: $cond?
828 =item Return Value: $resultsetcolumn
832 my $max_length = $rs->get_column('length')->max;
834 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
839 my ($self, $column) = @_;
840 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
848 =item Arguments: $cond, \%attrs?
850 =item Return Value: $resultset (scalar context), @row_objs (list context)
854 # WHERE title LIKE '%blue%'
855 $cd_rs = $rs->search_like({ title => '%blue%'});
857 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
858 that this is simply a convenience method retained for ex Class::DBI users.
859 You most likely want to use L</search> with specific operators.
861 For more information, see L<DBIx::Class::Manual::Cookbook>.
863 This method is deprecated and will be removed in 0.09. Use L</search()>
864 instead. An example conversion is:
866 ->search_like({ foo => 'bar' });
870 ->search({ foo => { like => 'bar' } });
877 'search_like() is deprecated and will be removed in 0.09.',
878 'Instead use ->search({ x => { -like => "y%" } })',
879 '(note the outer pair of {}s - they are important!)'
881 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
882 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
883 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
884 return $class->search($query, { %$attrs });
891 =item Arguments: $first, $last
893 =item Return Value: $resultset (scalar context), @row_objs (list context)
897 Returns a resultset or object list representing a subset of elements from the
898 resultset slice is called on. Indexes are from 0, i.e., to get the first
901 my ($one, $two, $three) = $rs->slice(0, 2);
906 my ($self, $min, $max) = @_;
907 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
908 $attrs->{offset} = $self->{attrs}{offset} || 0;
909 $attrs->{offset} += $min;
910 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
911 return $self->search(undef(), $attrs);
912 #my $slice = (ref $self)->new($self->result_source, $attrs);
913 #return (wantarray ? $slice->all : $slice);
920 =item Arguments: none
922 =item Return Value: $result?
926 Returns the next element in the resultset (C<undef> is there is none).
928 Can be used to efficiently iterate over records in the resultset:
930 my $rs = $schema->resultset('CD')->search;
931 while (my $cd = $rs->next) {
935 Note that you need to store the resultset object, and call C<next> on it.
936 Calling C<< resultset('Table')->next >> repeatedly will always return the
937 first record from the resultset.
943 if (my $cache = $self->get_cache) {
944 $self->{all_cache_position} ||= 0;
945 return $cache->[$self->{all_cache_position}++];
947 if ($self->{attrs}{cache}) {
948 $self->{all_cache_position} = 1;
949 return ($self->all)[0];
951 if ($self->{stashed_objects}) {
952 my $obj = shift(@{$self->{stashed_objects}});
953 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
957 exists $self->{stashed_row}
958 ? @{delete $self->{stashed_row}}
959 : $self->cursor->next
961 return undef unless (@row);
962 my ($row, @more) = $self->_construct_object(@row);
963 $self->{stashed_objects} = \@more if @more;
967 sub _construct_object {
968 my ($self, @row) = @_;
969 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
970 my @new = $self->result_class->inflate_result($self->result_source, @$info);
971 @new = $self->{_attrs}{record_filter}->(@new)
972 if exists $self->{_attrs}{record_filter};
976 sub _collapse_result {
977 my ($self, $as_proto, $row) = @_;
981 # 'foo' => [ undef, 'foo' ]
982 # 'foo.bar' => [ 'foo', 'bar' ]
983 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
985 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
987 my %collapse = %{$self->{_attrs}{collapse}||{}};
991 # if we're doing collapsing (has_many prefetch) we need to grab records
992 # until the PK changes, so fill @pri_index. if not, we leave it empty so
993 # we know we don't have to bother.
995 # the reason for not using the collapse stuff directly is because if you
996 # had for e.g. two artists in a row with no cds, the collapse info for
997 # both would be NULL (undef) so you'd lose the second artist
999 # store just the index so we can check the array positions from the row
1000 # without having to contruct the full hash
1002 if (keys %collapse) {
1003 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1004 foreach my $i (0 .. $#construct_as) {
1005 next if defined($construct_as[$i][0]); # only self table
1006 if (delete $pri{$construct_as[$i][1]}) {
1007 push(@pri_index, $i);
1009 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1013 # no need to do an if, it'll be empty if @pri_index is empty anyway
1015 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1019 do { # no need to check anything at the front, we always want the first row
1023 foreach my $this_as (@construct_as) {
1024 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1027 push(@const_rows, \%const);
1029 } until ( # no pri_index => no collapse => drop straight out
1032 do { # get another row, stash it, drop out if different PK
1034 @copy = $self->cursor->next;
1035 $self->{stashed_row} = \@copy;
1037 # last thing in do block, counts as true if anything doesn't match
1039 # check xor defined first for NULL vs. NOT NULL then if one is
1040 # defined the other must be so check string equality
1043 (defined $pri_vals{$_} ^ defined $copy[$_])
1044 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1049 my $alias = $self->{attrs}{alias};
1056 foreach my $const (@const_rows) {
1057 scalar @const_keys or do {
1058 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1060 foreach my $key (@const_keys) {
1063 my @parts = split(/\./, $key);
1065 my $data = $const->{$key};
1066 foreach my $p (@parts) {
1067 $target = $target->[1]->{$p} ||= [];
1069 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1070 # collapsing at this point and on final part
1071 my $pos = $collapse_pos{$cur};
1072 CK: foreach my $ck (@ckey) {
1073 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1074 $collapse_pos{$cur} = $data;
1075 delete @collapse_pos{ # clear all positioning for sub-entries
1076 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1083 if (exists $collapse{$cur}) {
1084 $target = $target->[-1];
1087 $target->[0] = $data;
1089 $info->[0] = $const->{$key};
1097 =head2 result_source
1101 =item Arguments: $result_source?
1103 =item Return Value: $result_source
1107 An accessor for the primary ResultSource object from which this ResultSet
1114 =item Arguments: $result_class?
1116 =item Return Value: $result_class
1120 An accessor for the class to use when creating row objects. Defaults to
1121 C<< result_source->result_class >> - which in most cases is the name of the
1122 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1127 my ($self, $result_class) = @_;
1128 if ($result_class) {
1129 $self->ensure_class_loaded($result_class);
1130 $self->_result_class($result_class);
1132 $self->_result_class;
1139 =item Arguments: $cond, \%attrs??
1141 =item Return Value: $count
1145 Performs an SQL C<COUNT> with the same query as the resultset was built
1146 with to find the number of elements. If passed arguments, does a search
1147 on the resultset and counts the results of that.
1149 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1150 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1151 not support C<DISTINCT> with multiple columns. If you are using such a
1152 database, you should only use columns from the main table in your C<group_by>
1159 return $self->search(@_)->count if @_ and defined $_[0];
1160 return scalar @{ $self->get_cache } if $self->get_cache;
1161 my $count = $self->_count;
1162 return 0 unless $count;
1164 # need to take offset from resolved attrs
1166 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1167 $count = $self->{attrs}{rows} if
1168 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1169 $count = 0 if ($count < 0);
1173 sub _count { # Separated out so pager can get the full count
1175 my $select = { count => '*' };
1177 my $attrs = { %{$self->_resolved_attrs} };
1178 if (my $group_by = delete $attrs->{group_by}) {
1179 delete $attrs->{having};
1180 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1181 # todo: try CONCAT for multi-column pk
1182 my @pk = $self->result_source->primary_columns;
1184 my $alias = $attrs->{alias};
1185 foreach my $column (@distinct) {
1186 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1187 @distinct = ($column);
1193 $select = { count => { distinct => \@distinct } };
1196 $attrs->{select} = $select;
1197 $attrs->{as} = [qw/count/];
1199 # offset, order by and page are not needed to count. record_filter is cdbi
1200 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1202 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1203 my ($count) = $tmp_rs->cursor->next;
1211 =head2 count_literal
1215 =item Arguments: $sql_fragment, @bind_values
1217 =item Return Value: $count
1221 Counts the results in a literal query. Equivalent to calling L</search_literal>
1222 with the passed arguments, then L</count>.
1226 sub count_literal { shift->search_literal(@_)->count; }
1232 =item Arguments: none
1234 =item Return Value: @objects
1238 Returns all elements in the resultset. Called implicitly if the resultset
1239 is returned in list context.
1246 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1249 return @{ $self->get_cache } if $self->get_cache;
1253 # TODO: don't call resolve here
1254 if (keys %{$self->_resolved_attrs->{collapse}}) {
1255 # if ($self->{attrs}{prefetch}) {
1256 # Using $self->cursor->all is really just an optimisation.
1257 # If we're collapsing has_many prefetches it probably makes
1258 # very little difference, and this is cleaner than hacking
1259 # _construct_object to survive the approach
1260 my @row = $self->cursor->next;
1262 push(@obj, $self->_construct_object(@row));
1263 @row = (exists $self->{stashed_row}
1264 ? @{delete $self->{stashed_row}}
1265 : $self->cursor->next);
1268 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1271 $self->set_cache(\@obj) if $self->{attrs}{cache};
1279 =item Arguments: none
1281 =item Return Value: $self
1285 Resets the resultset's cursor, so you can iterate through the elements again.
1291 delete $self->{_attrs} if exists $self->{_attrs};
1292 $self->{all_cache_position} = 0;
1293 $self->cursor->reset;
1301 =item Arguments: none
1303 =item Return Value: $object?
1307 Resets the resultset and returns an object for the first result (if the
1308 resultset returns anything).
1313 return $_[0]->reset->next;
1316 # _cond_for_update_delete
1318 # update/delete require the condition to be modified to handle
1319 # the differing SQL syntax available. This transforms the $self->{cond}
1320 # appropriately, returning the new condition.
1322 sub _cond_for_update_delete {
1323 my ($self, $full_cond) = @_;
1326 $full_cond ||= $self->{cond};
1327 # No-op. No condition, we're updating/deleting everything
1328 return $cond unless ref $full_cond;
1330 if (ref $full_cond eq 'ARRAY') {
1334 foreach my $key (keys %{$_}) {
1336 $hash{$1} = $_->{$key};
1342 elsif (ref $full_cond eq 'HASH') {
1343 if ((keys %{$full_cond})[0] eq '-and') {
1346 my @cond = @{$full_cond->{-and}};
1347 for (my $i = 0; $i < @cond; $i++) {
1348 my $entry = $cond[$i];
1351 if (ref $entry eq 'HASH') {
1352 $hash = $self->_cond_for_update_delete($entry);
1355 $entry =~ /([^.]+)$/;
1356 $hash->{$1} = $cond[++$i];
1359 push @{$cond->{-and}}, $hash;
1363 foreach my $key (keys %{$full_cond}) {
1365 $cond->{$1} = $full_cond->{$key};
1370 $self->throw_exception(
1371 "Can't update/delete on resultset with condition unless hash or array"
1383 =item Arguments: \%values
1385 =item Return Value: $storage_rv
1389 Sets the specified columns in the resultset to the supplied values in a
1390 single query. Return value will be true if the update succeeded or false
1391 if no records were updated; exact type of success value is storage-dependent.
1396 my ($self, $values) = @_;
1397 $self->throw_exception("Values for update must be a hash")
1398 unless ref $values eq 'HASH';
1400 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1401 . ' on joined resultsets, and may affect rows well outside of the'
1402 . ' contents of $rs. Use at your own risk' )
1403 if ( $self->{attrs}{seen_join} );
1405 my $cond = $self->_cond_for_update_delete;
1407 return $self->result_source->storage->update(
1408 $self->result_source, $values, $cond
1416 =item Arguments: \%values
1418 =item Return Value: 1
1422 Fetches all objects and updates them one at a time. Note that C<update_all>
1423 will run DBIC cascade triggers, while L</update> will not.
1428 my ($self, $values) = @_;
1429 $self->throw_exception("Values for update must be a hash")
1430 unless ref $values eq 'HASH';
1431 foreach my $obj ($self->all) {
1432 $obj->set_columns($values)->update;
1441 =item Arguments: none
1443 =item Return Value: 1
1447 Deletes the contents of the resultset from its result source. Note that this
1448 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1449 to run. See also L<DBIx::Class::Row/delete>.
1451 delete may not generate correct SQL for a query with joins or a resultset
1452 chained from a related resultset. In this case it will generate a warning:-
1454 WARNING! Currently $rs->delete() does not generate proper SQL on
1455 joined resultsets, and may delete rows well outside of the contents
1456 of $rs. Use at your own risk
1458 In these cases you may find that delete_all is more appropriate, or you
1459 need to respecify your query in a way that can be expressed without a join.
1465 $self->throw_exception("Delete should not be passed any arguments")
1467 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1468 . ' on joined resultsets, and may delete rows well outside of the'
1469 . ' contents of $rs. Use at your own risk' )
1470 if ( $self->{attrs}{seen_join} );
1471 my $cond = $self->_cond_for_update_delete;
1473 $self->result_source->storage->delete($self->result_source, $cond);
1481 =item Arguments: none
1483 =item Return Value: 1
1487 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1488 will run DBIC cascade triggers, while L</delete> will not.
1494 $_->delete for $self->all;
1502 =item Arguments: \@data;
1506 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1507 For the arrayref of hashrefs style each hashref should be a structure suitable
1508 forsubmitting to a $resultset->create(...) method.
1510 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1511 to insert the data, as this is a faster method.
1513 Otherwise, each set of data is inserted into the database using
1514 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1515 objects is returned.
1517 Example: Assuming an Artist Class that has many CDs Classes relating:
1519 my $Artist_rs = $schema->resultset("Artist");
1521 ## Void Context Example
1522 $Artist_rs->populate([
1523 { artistid => 4, name => 'Manufactured Crap', cds => [
1524 { title => 'My First CD', year => 2006 },
1525 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1528 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1529 { title => 'My parents sold me to a record company' ,year => 2005 },
1530 { title => 'Why Am I So Ugly?', year => 2006 },
1531 { title => 'I Got Surgery and am now Popular', year => 2007 }
1536 ## Array Context Example
1537 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1538 { name => "Artist One"},
1539 { name => "Artist Two"},
1540 { name => "Artist Three", cds=> [
1541 { title => "First CD", year => 2007},
1542 { title => "Second CD", year => 2008},
1546 print $ArtistOne->name; ## response is 'Artist One'
1547 print $ArtistThree->cds->count ## reponse is '2'
1549 For the arrayref of arrayrefs style, the first element should be a list of the
1550 fieldsnames to which the remaining elements are rows being inserted. For
1553 $Arstist_rs->populate([
1554 [qw/artistid name/],
1555 [100, 'A Formally Unknown Singer'],
1556 [101, 'A singer that jumped the shark two albums ago'],
1557 [102, 'An actually cool singer.'],
1560 Please note an important effect on your data when choosing between void and
1561 wantarray context. Since void context goes straight to C<insert_bulk> in
1562 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1563 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1564 create primary keys for you, you will find that your PKs are empty. In this
1565 case you will have to use the wantarray context in order to create those
1571 my $self = shift @_;
1572 my $data = ref $_[0][0] eq 'HASH'
1573 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1574 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1576 if(defined wantarray) {
1578 foreach my $item (@$data) {
1579 push(@created, $self->create($item));
1583 my ($first, @rest) = @$data;
1585 my @names = grep {!ref $first->{$_}} keys %$first;
1586 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1587 my @pks = $self->result_source->primary_columns;
1589 ## do the belongs_to relationships
1590 foreach my $index (0..$#$data) {
1591 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1592 my @ret = $self->populate($data);
1596 foreach my $rel (@rels) {
1597 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1598 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1599 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1600 my $related = $result->result_source->resolve_condition(
1601 $result->result_source->relationship_info($reverse)->{cond},
1606 delete $data->[$index]->{$rel};
1607 $data->[$index] = {%{$data->[$index]}, %$related};
1609 push @names, keys %$related if $index == 0;
1613 ## do bulk insert on current row
1614 my @values = map { [ @$_{@names} ] } @$data;
1616 $self->result_source->storage->insert_bulk(
1617 $self->result_source,
1622 ## do the has_many relationships
1623 foreach my $item (@$data) {
1625 foreach my $rel (@rels) {
1626 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1628 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1629 || $self->throw_exception('Cannot find the relating object.');
1631 my $child = $parent->$rel;
1633 my $related = $child->result_source->resolve_condition(
1634 $parent->result_source->relationship_info($rel)->{cond},
1639 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1640 my @populate = map { {%$_, %$related} } @rows_to_add;
1642 $child->populate( \@populate );
1648 =head2 _normalize_populate_args ($args)
1650 Private method used by L</populate> to normalize its incoming arguments. Factored
1651 out in case you want to subclass and accept new argument structures to the
1652 L</populate> method.
1656 sub _normalize_populate_args {
1657 my ($self, $data) = @_;
1658 my @names = @{shift(@$data)};
1659 my @results_to_create;
1660 foreach my $datum (@$data) {
1661 my %result_to_create;
1662 foreach my $index (0..$#names) {
1663 $result_to_create{$names[$index]} = $$datum[$index];
1665 push @results_to_create, \%result_to_create;
1667 return \@results_to_create;
1674 =item Arguments: none
1676 =item Return Value: $pager
1680 Return Value a L<Data::Page> object for the current resultset. Only makes
1681 sense for queries with a C<page> attribute.
1683 To get the full count of entries for a paged resultset, call
1684 C<total_entries> on the L<Data::Page> object.
1690 my $attrs = $self->{attrs};
1691 $self->throw_exception("Can't create pager for non-paged rs")
1692 unless $self->{attrs}{page};
1693 $attrs->{rows} ||= 10;
1694 return $self->{pager} ||= Data::Page->new(
1695 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1702 =item Arguments: $page_number
1704 =item Return Value: $rs
1708 Returns a resultset for the $page_number page of the resultset on which page
1709 is called, where each page contains a number of rows equal to the 'rows'
1710 attribute set on the resultset (10 by default).
1715 my ($self, $page) = @_;
1716 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1723 =item Arguments: \%vals
1725 =item Return Value: $rowobject
1729 Creates a new row object in the resultset's result class and returns
1730 it. The row is not inserted into the database at this point, call
1731 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1732 will tell you whether the row object has been inserted or not.
1734 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1739 my ($self, $values) = @_;
1740 $self->throw_exception( "new_result needs a hash" )
1741 unless (ref $values eq 'HASH');
1744 my $alias = $self->{attrs}{alias};
1747 defined $self->{cond}
1748 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1750 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1751 $new{-from_resultset} = [ keys %new ] if keys %new;
1753 $self->throw_exception(
1754 "Can't abstract implicit construct, condition not a hash"
1755 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1757 my $collapsed_cond = (
1759 ? $self->_collapse_cond($self->{cond})
1763 # precendence must be given to passed values over values inherited from
1764 # the cond, so the order here is important.
1765 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1766 while( my($col,$value) = each %implied ){
1767 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1768 $new{$col} = $value->{'='};
1771 $new{$col} = $value if $self->_is_deterministic_value($value);
1777 %{ $self->_remove_alias($values, $alias) },
1778 -source_handle => $self->_source_handle,
1779 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1782 return $self->result_class->new(\%new);
1785 # _is_deterministic_value
1787 # Make an effor to strip non-deterministic values from the condition,
1788 # to make sure new_result chokes less
1790 sub _is_deterministic_value {
1793 my $ref_type = ref $value;
1794 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1795 return 1 if Scalar::Util::blessed($value);
1801 # Recursively collapse the condition.
1803 sub _collapse_cond {
1804 my ($self, $cond, $collapsed) = @_;
1808 if (ref $cond eq 'ARRAY') {
1809 foreach my $subcond (@$cond) {
1810 next unless ref $subcond; # -or
1811 # warn "ARRAY: " . Dumper $subcond;
1812 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1815 elsif (ref $cond eq 'HASH') {
1816 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1817 foreach my $subcond (@{$cond->{-and}}) {
1818 # warn "HASH: " . Dumper $subcond;
1819 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1823 # warn "LEAF: " . Dumper $cond;
1824 foreach my $col (keys %$cond) {
1825 my $value = $cond->{$col};
1826 $collapsed->{$col} = $value;
1836 # Remove the specified alias from the specified query hash. A copy is made so
1837 # the original query is not modified.
1840 my ($self, $query, $alias) = @_;
1842 my %orig = %{ $query || {} };
1845 foreach my $key (keys %orig) {
1847 $unaliased{$key} = $orig{$key};
1850 $unaliased{$1} = $orig{$key}
1851 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1857 =head2 as_query (EXPERIMENTAL)
1861 =item Arguments: none
1863 =item Return Value: \[ $sql, @bind ]
1867 Returns the SQL query and bind vars associated with the invocant.
1869 This is generally used as the RHS for a subquery.
1871 B<NOTE>: This feature is still experimental.
1875 sub as_query { return shift->cursor->as_query(@_) }
1881 =item Arguments: \%vals, \%attrs?
1883 =item Return Value: $rowobject
1887 my $artist = $schema->resultset('Artist')->find_or_new(
1888 { artist => 'fred' }, { key => 'artists' });
1890 $cd->cd_to_producer->find_or_new({ producer => $producer },
1891 { key => 'primary });
1893 Find an existing record from this resultset, based on its primary
1894 key, or a unique constraint. If none exists, instantiate a new result
1895 object and return it. The object will not be saved into your storage
1896 until you call L<DBIx::Class::Row/insert> on it.
1898 You most likely want this method when looking for existing rows using
1899 a unique constraint that is not the primary key, or looking for
1902 If you want objects to be saved immediately, use L</find_or_create> instead.
1904 B<Note>: C<find_or_new> is probably not what you want when creating a
1905 new row in a table that uses primary keys supplied by the
1906 database. Passing in a primary key column with a value of I<undef>
1907 will cause L</find> to attempt to search for a row with a value of
1914 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1915 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1916 my $exists = $self->find($hash, $attrs);
1917 return defined $exists ? $exists : $self->new_result($hash);
1924 =item Arguments: \%vals
1926 =item Return Value: a L<DBIx::Class::Row> $object
1930 Attempt to create a single new row or a row with multiple related rows
1931 in the table represented by the resultset (and related tables). This
1932 will not check for duplicate rows before inserting, use
1933 L</find_or_create> to do that.
1935 To create one row for this resultset, pass a hashref of key/value
1936 pairs representing the columns of the table and the values you wish to
1937 store. If the appropriate relationships are set up, foreign key fields
1938 can also be passed an object representing the foreign row, and the
1939 value will be set to its primary key.
1941 To create related objects, pass a hashref for the value if the related
1942 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1943 and use the name of the relationship as the key. (NOT the name of the field,
1944 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1945 of hashrefs containing the data for each of the rows to create in the foreign
1946 tables, again using the relationship name as the key.
1948 Instead of hashrefs of plain related data (key/value pairs), you may
1949 also pass new or inserted objects. New objects (not inserted yet, see
1950 L</new>), will be inserted into their appropriate tables.
1952 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1954 Example of creating a new row.
1956 $person_rs->create({
1957 name=>"Some Person",
1958 email=>"somebody@someplace.com"
1961 Example of creating a new row and also creating rows in a related C<has_many>
1962 or C<has_one> resultset. Note Arrayref.
1965 { artistid => 4, name => 'Manufactured Crap', cds => [
1966 { title => 'My First CD', year => 2006 },
1967 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1972 Example of creating a new row and also creating a row in a related
1973 C<belongs_to>resultset. Note Hashref.
1976 title=>"Music for Silly Walks",
1979 name=>"Silly Musician",
1986 my ($self, $attrs) = @_;
1987 $self->throw_exception( "create needs a hashref" )
1988 unless ref $attrs eq 'HASH';
1989 return $self->new_result($attrs)->insert;
1992 =head2 find_or_create
1996 =item Arguments: \%vals, \%attrs?
1998 =item Return Value: $rowobject
2002 $cd->cd_to_producer->find_or_create({ producer => $producer },
2003 { key => 'primary });
2005 Tries to find a record based on its primary key or unique constraints; if none
2006 is found, creates one and returns that instead.
2008 my $cd = $schema->resultset('CD')->find_or_create({
2010 artist => 'Massive Attack',
2011 title => 'Mezzanine',
2015 Also takes an optional C<key> attribute, to search by a specific key or unique
2016 constraint. For example:
2018 my $cd = $schema->resultset('CD')->find_or_create(
2020 artist => 'Massive Attack',
2021 title => 'Mezzanine',
2023 { key => 'cd_artist_title' }
2026 B<Note>: Because find_or_create() reads from the database and then
2027 possibly inserts based on the result, this method is subject to a race
2028 condition. Another process could create a record in the table after
2029 the find has completed and before the create has started. To avoid
2030 this problem, use find_or_create() inside a transaction.
2032 B<Note>: C<find_or_create> is probably not what you want when creating
2033 a new row in a table that uses primary keys supplied by the
2034 database. Passing in a primary key column with a value of I<undef>
2035 will cause L</find> to attempt to search for a row with a value of
2038 See also L</find> and L</update_or_create>. For information on how to declare
2039 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2043 sub find_or_create {
2045 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2046 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2047 my $exists = $self->find($hash, $attrs);
2048 return defined $exists ? $exists : $self->create($hash);
2051 =head2 update_or_create
2055 =item Arguments: \%col_values, { key => $unique_constraint }?
2057 =item Return Value: $rowobject
2061 $resultset->update_or_create({ col => $val, ... });
2063 First, searches for an existing row matching one of the unique constraints
2064 (including the primary key) on the source of this resultset. If a row is
2065 found, updates it with the other given column values. Otherwise, creates a new
2068 Takes an optional C<key> attribute to search on a specific unique constraint.
2071 # In your application
2072 my $cd = $schema->resultset('CD')->update_or_create(
2074 artist => 'Massive Attack',
2075 title => 'Mezzanine',
2078 { key => 'cd_artist_title' }
2081 $cd->cd_to_producer->update_or_create({
2082 producer => $producer,
2089 If no C<key> is specified, it searches on all unique constraints defined on the
2090 source, including the primary key.
2092 If the C<key> is specified as C<primary>, it searches only on the primary key.
2094 See also L</find> and L</find_or_create>. For information on how to declare
2095 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2097 B<Note>: C<update_or_create> is probably not what you want when
2098 looking for a row in a table that uses primary keys supplied by the
2099 database, unless you actually have a key value. Passing in a primary
2100 key column with a value of I<undef> will cause L</find> to attempt to
2101 search for a row with a value of I<NULL>.
2105 sub update_or_create {
2107 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2108 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2110 my $row = $self->find($cond, $attrs);
2112 $row->update($cond);
2116 return $self->create($cond);
2119 =head2 update_or_new
2123 =item Arguments: \%col_values, { key => $unique_constraint }?
2125 =item Return Value: $rowobject
2129 $resultset->update_or_new({ 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, instantiate
2134 a new result object and return it. The object will not be saved into your storage
2135 until you call L<DBIx::Class::Row/insert> on it.
2137 Takes an optional C<key> attribute to search on a specific unique constraint.
2140 # In your application
2141 my $cd = $schema->resultset('CD')->update_or_new(
2143 artist => 'Massive Attack',
2144 title => 'Mezzanine',
2147 { key => 'cd_artist_title' }
2150 if ($cd->in_storage) {
2151 # the cd was updated
2154 # the cd is not yet in the database, let's insert it
2158 See also L</find>, L</find_or_create> and L<find_or_new>.
2164 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2165 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2167 my $row = $self->find( $cond, $attrs );
2168 if ( defined $row ) {
2169 $row->update($cond);
2173 return $self->new_result($cond);
2180 =item Arguments: none
2182 =item Return Value: \@cache_objects?
2186 Gets the contents of the cache for the resultset, if the cache is set.
2188 The cache is populated either by using the L</prefetch> attribute to
2189 L</search> or by calling L</set_cache>.
2201 =item Arguments: \@cache_objects
2203 =item Return Value: \@cache_objects
2207 Sets the contents of the cache for the resultset. Expects an arrayref
2208 of objects of the same class as those produced by the resultset. Note that
2209 if the cache is set the resultset will return the cached objects rather
2210 than re-querying the database even if the cache attr is not set.
2212 The contents of the cache can also be populated by using the
2213 L</prefetch> attribute to L</search>.
2218 my ( $self, $data ) = @_;
2219 $self->throw_exception("set_cache requires an arrayref")
2220 if defined($data) && (ref $data ne 'ARRAY');
2221 $self->{all_cache} = $data;
2228 =item Arguments: none
2230 =item Return Value: []
2234 Clears the cache for the resultset.
2239 shift->set_cache(undef);
2242 =head2 related_resultset
2246 =item Arguments: $relationship_name
2248 =item Return Value: $resultset
2252 Returns a related resultset for the supplied relationship name.
2254 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2258 sub related_resultset {
2259 my ($self, $rel) = @_;
2261 $self->{related_resultsets} ||= {};
2262 return $self->{related_resultsets}{$rel} ||= do {
2263 my $rel_obj = $self->result_source->relationship_info($rel);
2265 $self->throw_exception(
2266 "search_related: result source '" . $self->result_source->source_name .
2267 "' has no such relationship $rel")
2270 my ($from,$seen) = $self->_resolve_from($rel);
2272 my $join_count = $seen->{$rel};
2273 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2275 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2276 my %attrs = %{$self->{attrs}||{}};
2277 delete @attrs{qw(result_class alias)};
2281 if (my $cache = $self->get_cache) {
2282 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2283 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2288 my $rel_source = $self->result_source->related_source($rel);
2292 # The reason we do this now instead of passing the alias to the
2293 # search_rs below is that if you wrap/overload resultset on the
2294 # source you need to know what alias it's -going- to have for things
2295 # to work sanely (e.g. RestrictWithObject wants to be able to add
2296 # extra query restrictions, and these may need to be $alias.)
2298 my $attrs = $rel_source->resultset_attributes;
2299 local $attrs->{alias} = $alias;
2301 $rel_source->resultset
2309 where => $self->{cond},
2314 $new->set_cache($new_cache) if $new_cache;
2319 =head2 current_source_alias
2323 =item Arguments: none
2325 =item Return Value: $source_alias
2329 Returns the current table alias for the result source this resultset is built
2330 on, that will be used in the SQL query. Usually it is C<me>.
2332 Currently the source alias that refers to the result set returned by a
2333 L</search>/L</find> family method depends on how you got to the resultset: it's
2334 C<me> by default, but eg. L</search_related> aliases it to the related result
2335 source name (and keeps C<me> referring to the original result set). The long
2336 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2337 (and make this method unnecessary).
2339 Thus it's currently necessary to use this method in predefined queries (see
2340 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2341 source alias of the current result set:
2343 # in a result set class
2345 my ($self, $user) = @_;
2347 my $me = $self->current_source_alias;
2349 return $self->search(
2350 "$me.modified" => $user->id,
2356 sub current_source_alias {
2359 return ($self->{attrs} || {})->{alias} || 'me';
2363 my ($self, $extra_join) = @_;
2364 my $source = $self->result_source;
2365 my $attrs = $self->{attrs};
2367 my $from = $attrs->{from}
2368 || [ { $attrs->{alias} => $source->from } ];
2370 my $seen = { %{$attrs->{seen_join}||{}} };
2372 my $join = ($attrs->{join}
2373 ? [ $attrs->{join}, $extra_join ]
2376 # we need to take the prefetch the attrs into account before we
2377 # ->resolve_join as otherwise they get lost - captainL
2378 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2382 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2385 return ($from,$seen);
2388 sub _resolved_attrs {
2390 return $self->{_attrs} if $self->{_attrs};
2392 my $attrs = { %{ $self->{attrs} || {} } };
2393 my $source = $self->result_source;
2394 my $alias = $attrs->{alias};
2396 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2399 # build columns (as long as select isn't set) into a set of as/select hashes
2400 unless ( $attrs->{select} ) {
2402 ( ref($_) eq 'HASH' ) ? $_
2405 /^\Q${alias}.\E(.+)$/ ? $1
2407 ) => ( /\./ ? $_ : "${alias}.$_" )
2409 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2411 # add the additional columns on
2412 foreach ( 'include_columns', '+columns' ) {
2413 push @colbits, map {
2414 ( ref($_) eq 'HASH' )
2416 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2417 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2420 # start with initial select items
2421 if ( $attrs->{select} ) {
2423 ( ref $attrs->{select} eq 'ARRAY' )
2424 ? [ @{ $attrs->{select} } ]
2425 : [ $attrs->{select} ];
2429 ref $attrs->{as} eq 'ARRAY'
2430 ? [ @{ $attrs->{as} } ]
2433 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2438 # otherwise we intialise select & as to empty
2439 $attrs->{select} = [];
2443 # now add colbits to select/as
2444 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2445 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2448 if ( $adds = delete $attrs->{'+select'} ) {
2449 $adds = [$adds] unless ref $adds eq 'ARRAY';
2451 @{ $attrs->{select} },
2452 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2455 if ( $adds = delete $attrs->{'+as'} ) {
2456 $adds = [$adds] unless ref $adds eq 'ARRAY';
2457 push( @{ $attrs->{as} }, @$adds );
2460 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2462 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2463 my $join = delete $attrs->{join} || {};
2465 if ( defined $attrs->{prefetch} ) {
2466 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2470 $attrs->{from} = # have to copy here to avoid corrupting the original
2472 @{ $attrs->{from} },
2473 $source->resolve_join(
2474 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2480 $attrs->{group_by} ||= $attrs->{select}
2481 if delete $attrs->{distinct};
2482 if ( $attrs->{order_by} ) {
2483 $attrs->{order_by} = (
2484 ref( $attrs->{order_by} ) eq 'ARRAY'
2485 ? [ @{ $attrs->{order_by} } ]
2486 : [ $attrs->{order_by} ]
2490 $attrs->{order_by} = [];
2493 my $collapse = $attrs->{collapse} || {};
2494 if ( my $prefetch = delete $attrs->{prefetch} ) {
2495 $prefetch = $self->_merge_attr( {}, $prefetch );
2497 my $seen = { %{ $attrs->{seen_join} || {} } };
2498 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2500 # bring joins back to level of current class
2502 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2503 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2504 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2506 push( @{ $attrs->{order_by} }, @pre_order );
2508 $attrs->{collapse} = $collapse;
2510 if ( $attrs->{page} ) {
2511 $attrs->{offset} ||= 0;
2512 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2515 return $self->{_attrs} = $attrs;
2519 my ($self, $attr) = @_;
2521 if (ref $attr eq 'HASH') {
2522 return $self->_rollout_hash($attr);
2523 } elsif (ref $attr eq 'ARRAY') {
2524 return $self->_rollout_array($attr);
2530 sub _rollout_array {
2531 my ($self, $attr) = @_;
2534 foreach my $element (@{$attr}) {
2535 if (ref $element eq 'HASH') {
2536 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2537 } elsif (ref $element eq 'ARRAY') {
2538 # XXX - should probably recurse here
2539 push( @rolled_array, @{$self->_rollout_array($element)} );
2541 push( @rolled_array, $element );
2544 return \@rolled_array;
2548 my ($self, $attr) = @_;
2551 foreach my $key (keys %{$attr}) {
2552 push( @rolled_array, { $key => $attr->{$key} } );
2554 return \@rolled_array;
2557 sub _calculate_score {
2558 my ($self, $a, $b) = @_;
2560 if (ref $b eq 'HASH') {
2561 my ($b_key) = keys %{$b};
2562 if (ref $a eq 'HASH') {
2563 my ($a_key) = keys %{$a};
2564 if ($a_key eq $b_key) {
2565 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2570 return ($a eq $b_key) ? 1 : 0;
2573 if (ref $a eq 'HASH') {
2574 my ($a_key) = keys %{$a};
2575 return ($b eq $a_key) ? 1 : 0;
2577 return ($b eq $a) ? 1 : 0;
2583 my ($self, $orig, $import) = @_;
2585 return $import unless defined($orig);
2586 return $orig unless defined($import);
2588 $orig = $self->_rollout_attr($orig);
2589 $import = $self->_rollout_attr($import);
2592 foreach my $import_element ( @{$import} ) {
2593 # find best candidate from $orig to merge $b_element into
2594 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2595 foreach my $orig_element ( @{$orig} ) {
2596 my $score = $self->_calculate_score( $orig_element, $import_element );
2597 if ($score > $best_candidate->{score}) {
2598 $best_candidate->{position} = $position;
2599 $best_candidate->{score} = $score;
2603 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2605 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2606 push( @{$orig}, $import_element );
2608 my $orig_best = $orig->[$best_candidate->{position}];
2609 # merge orig_best and b_element together and replace original with merged
2610 if (ref $orig_best ne 'HASH') {
2611 $orig->[$best_candidate->{position}] = $import_element;
2612 } elsif (ref $import_element eq 'HASH') {
2613 my ($key) = keys %{$orig_best};
2614 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2617 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2627 $self->_source_handle($_[0]->handle);
2629 $self->_source_handle->resolve;
2633 =head2 throw_exception
2635 See L<DBIx::Class::Schema/throw_exception> for details.
2639 sub throw_exception {
2641 if (ref $self && $self->_source_handle->schema) {
2642 $self->_source_handle->schema->throw_exception(@_)
2649 # XXX: FIXME: Attributes docs need clearing up
2653 Attributes are used to refine a ResultSet in various ways when
2654 searching for data. They can be passed to any method which takes an
2655 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2658 These are in no particular order:
2664 =item Value: ( $order_by | \@order_by | \%order_by )
2668 Which column(s) to order the results by. If a single column name, or
2669 an arrayref of names is supplied, the argument is passed through
2670 directly to SQL. The hashref syntax allows for connection-agnostic
2671 specification of ordering direction:
2673 For descending order:
2675 order_by => { -desc => [qw/col1 col2 col3/] }
2677 For explicit ascending order:
2679 order_by => { -asc => 'col' }
2681 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2682 supported, although you are strongly encouraged to use the hashref
2683 syntax as outlined above.
2689 =item Value: \@columns
2693 Shortcut to request a particular set of columns to be retrieved. Each
2694 column spec may be a string (a table column name), or a hash (in which
2695 case the key is the C<as> value, and the value is used as the C<select>
2696 expression). Adds C<me.> onto the start of any column without a C<.> in
2697 it and sets C<select> from that, then auto-populates C<as> from
2698 C<select> as normal. (You may also use the C<cols> attribute, as in
2699 earlier versions of DBIC.)
2705 =item Value: \@columns
2709 Indicates additional columns to be selected from storage. Works the same
2710 as L</columns> but adds columns to the selection. (You may also use the
2711 C<include_columns> attribute, as in earlier versions of DBIC). For
2714 $schema->resultset('CD')->search(undef, {
2715 '+columns' => ['artist.name'],
2719 would return all CDs and include a 'name' column to the information
2720 passed to object inflation. Note that the 'artist' is the name of the
2721 column (or relationship) accessor, and 'name' is the name of the column
2722 accessor in the related table.
2724 =head2 include_columns
2728 =item Value: \@columns
2732 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2738 =item Value: \@select_columns
2742 Indicates which columns should be selected from the storage. You can use
2743 column names, or in the case of RDBMS back ends, function or stored procedure
2746 $rs = $schema->resultset('Employee')->search(undef, {
2749 { count => 'employeeid' },
2754 When you use function/stored procedure names and do not supply an C<as>
2755 attribute, the column names returned are storage-dependent. E.g. MySQL would
2756 return a column named C<count(employeeid)> in the above example.
2762 Indicates additional columns to be selected from storage. Works the same as
2763 L</select> but adds columns to the selection.
2771 Indicates additional column names for those added via L</+select>. See L</as>.
2779 =item Value: \@inflation_names
2783 Indicates column names for object inflation. That is, C<as>
2784 indicates the name that the column can be accessed as via the
2785 C<get_column> method (or via the object accessor, B<if one already
2786 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2788 The C<as> attribute is used in conjunction with C<select>,
2789 usually when C<select> contains one or more function or stored
2792 $rs = $schema->resultset('Employee')->search(undef, {
2795 { count => 'employeeid' }
2797 as => ['name', 'employee_count'],
2800 my $employee = $rs->first(); # get the first Employee
2802 If the object against which the search is performed already has an accessor
2803 matching a column name specified in C<as>, the value can be retrieved using
2804 the accessor as normal:
2806 my $name = $employee->name();
2808 If on the other hand an accessor does not exist in the object, you need to
2809 use C<get_column> instead:
2811 my $employee_count = $employee->get_column('employee_count');
2813 You can create your own accessors if required - see
2814 L<DBIx::Class::Manual::Cookbook> for details.
2816 Please note: This will NOT insert an C<AS employee_count> into the SQL
2817 statement produced, it is used for internal access only. Thus
2818 attempting to use the accessor in an C<order_by> clause or similar
2819 will fail miserably.
2821 To get around this limitation, you can supply literal SQL to your
2822 C<select> attibute that contains the C<AS alias> text, eg:
2824 select => [\'myfield AS alias']
2830 =item Value: ($rel_name | \@rel_names | \%rel_names)
2834 Contains a list of relationships that should be joined for this query. For
2837 # Get CDs by Nine Inch Nails
2838 my $rs = $schema->resultset('CD')->search(
2839 { 'artist.name' => 'Nine Inch Nails' },
2840 { join => 'artist' }
2843 Can also contain a hash reference to refer to the other relation's relations.
2846 package MyApp::Schema::Track;
2847 use base qw/DBIx::Class/;
2848 __PACKAGE__->table('track');
2849 __PACKAGE__->add_columns(qw/trackid cd position title/);
2850 __PACKAGE__->set_primary_key('trackid');
2851 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2854 # In your application
2855 my $rs = $schema->resultset('Artist')->search(
2856 { 'track.title' => 'Teardrop' },
2858 join => { cd => 'track' },
2859 order_by => 'artist.name',
2863 You need to use the relationship (not the table) name in conditions,
2864 because they are aliased as such. The current table is aliased as "me", so
2865 you need to use me.column_name in order to avoid ambiguity. For example:
2867 # Get CDs from 1984 with a 'Foo' track
2868 my $rs = $schema->resultset('CD')->search(
2871 'tracks.name' => 'Foo'
2873 { join => 'tracks' }
2876 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2877 similarly for a third time). For e.g.
2879 my $rs = $schema->resultset('Artist')->search({
2880 'cds.title' => 'Down to Earth',
2881 'cds_2.title' => 'Popular',
2883 join => [ qw/cds cds/ ],
2886 will return a set of all artists that have both a cd with title 'Down
2887 to Earth' and a cd with title 'Popular'.
2889 If you want to fetch related objects from other tables as well, see C<prefetch>
2892 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2898 =item Value: ($rel_name | \@rel_names | \%rel_names)
2902 Contains one or more relationships that should be fetched along with
2903 the main query (when they are accessed afterwards the data will
2904 already be available, without extra queries to the database). This is
2905 useful for when you know you will need the related objects, because it
2906 saves at least one query:
2908 my $rs = $schema->resultset('Tag')->search(
2917 The initial search results in SQL like the following:
2919 SELECT tag.*, cd.*, artist.* FROM tag
2920 JOIN cd ON tag.cd = cd.cdid
2921 JOIN artist ON cd.artist = artist.artistid
2923 L<DBIx::Class> has no need to go back to the database when we access the
2924 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2927 Simple prefetches will be joined automatically, so there is no need
2928 for a C<join> attribute in the above search.
2930 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2931 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2932 with an accessor type of 'single' or 'filter'). A more complex example that
2933 prefetches an artists cds, the tracks on those cds, and the tags associted
2934 with that artist is given below (assuming many-to-many from artists to tags):
2936 my $rs = $schema->resultset('Artist')->search(
2940 { cds => 'tracks' },
2941 { artist_tags => 'tags' }
2947 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2948 attributes will be ignored.
2958 Makes the resultset paged and specifies the page to retrieve. Effectively
2959 identical to creating a non-pages resultset and then calling ->page($page)
2962 If L<rows> attribute is not specified it defualts to 10 rows per page.
2964 When you have a paged resultset, L</count> will only return the number
2965 of rows in the page. To get the total, use the L</pager> and call
2966 C<total_entries> on it.
2976 Specifes the maximum number of rows for direct retrieval or the number of
2977 rows per page if the page attribute or method is used.
2983 =item Value: $offset
2987 Specifies the (zero-based) row number for the first row to be returned, or the
2988 of the first row of the first page if paging is used.
2994 =item Value: \@columns
2998 A arrayref of columns to group by. Can include columns of joined tables.
3000 group_by => [qw/ column1 column2 ... /]
3006 =item Value: $condition
3010 HAVING is a select statement attribute that is applied between GROUP BY and
3011 ORDER BY. It is applied to the after the grouping calculations have been
3014 having => { 'count(employee)' => { '>=', 100 } }
3020 =item Value: (0 | 1)
3024 Set to 1 to group by all columns.
3030 Adds to the WHERE clause.
3032 # only return rows WHERE deleted IS NULL for all searches
3033 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3035 Can be overridden by passing C<{ where => undef }> as an attribute
3042 Set to 1 to cache search results. This prevents extra SQL queries if you
3043 revisit rows in your ResultSet:
3045 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3047 while( my $artist = $resultset->next ) {
3051 $rs->first; # without cache, this would issue a query
3053 By default, searches are not cached.
3055 For more examples of using these attributes, see
3056 L<DBIx::Class::Manual::Cookbook>.
3062 =item Value: \@from_clause
3066 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3067 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3070 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3072 C<join> will usually do what you need and it is strongly recommended that you
3073 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3074 And we really do mean "cannot", not just tried and failed. Attempting to use
3075 this because you're having problems with C<join> is like trying to use x86
3076 ASM because you've got a syntax error in your C. Trust us on this.
3078 Now, if you're still really, really sure you need to use this (and if you're
3079 not 100% sure, ask the mailing list first), here's an explanation of how this
3082 The syntax is as follows -
3085 { <alias1> => <table1> },
3087 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3088 [], # nested JOIN (optional)
3089 { <table1.column1> => <table2.column2>, ... (more conditions) },
3091 # More of the above [ ] may follow for additional joins
3098 ON <table1.column1> = <table2.column2>
3099 <more joins may follow>
3101 An easy way to follow the examples below is to remember the following:
3103 Anything inside "[]" is a JOIN
3104 Anything inside "{}" is a condition for the enclosing JOIN
3106 The following examples utilize a "person" table in a family tree application.
3107 In order to express parent->child relationships, this table is self-joined:
3109 # Person->belongs_to('father' => 'Person');
3110 # Person->belongs_to('mother' => 'Person');
3112 C<from> can be used to nest joins. Here we return all children with a father,
3113 then search against all mothers of those children:
3115 $rs = $schema->resultset('Person')->search(
3118 alias => 'mother', # alias columns in accordance with "from"
3120 { mother => 'person' },
3123 { child => 'person' },
3125 { father => 'person' },
3126 { 'father.person_id' => 'child.father_id' }
3129 { 'mother.person_id' => 'child.mother_id' }
3136 # SELECT mother.* FROM person mother
3139 # JOIN person father
3140 # ON ( father.person_id = child.father_id )
3142 # ON ( mother.person_id = child.mother_id )
3144 The type of any join can be controlled manually. To search against only people
3145 with a father in the person table, we could explicitly use C<INNER JOIN>:
3147 $rs = $schema->resultset('Person')->search(
3150 alias => 'child', # alias columns in accordance with "from"
3152 { child => 'person' },
3154 { father => 'person', -join_type => 'inner' },
3155 { 'father.id' => 'child.father_id' }
3162 # SELECT child.* FROM person child
3163 # INNER JOIN person father ON child.father_id = father.id
3165 If you need to express really complex joins or you need a subselect, you
3166 can supply literal SQL to C<from> via a scalar reference. In this case
3167 the contents of the scalar will replace the table name asscoiated with the
3170 WARNING: This technique might very well not work as expected on chained
3171 searches - you have been warned.
3173 # Assuming the Event resultsource is defined as:
3175 MySchema::Event->add_columns (
3178 is_auto_increment => 1,
3187 MySchema::Event->set_primary_key ('sequence');
3189 # This will get back the latest event for every location. The column
3190 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3191 # combo to limit the resultset
3193 $rs = $schema->resultset('Event');
3194 $table = $rs->result_source->name;
3195 $latest = $rs->search (
3198 (SELECT e1.* FROM $table e1
3200 ON e1.location = e2.location
3201 AND e1.sequence < e2.sequence
3202 WHERE e2.sequence is NULL
3207 # Equivalent SQL (with the DBIC chunks added):
3209 SELECT me.sequence, me.location, me.type FROM
3210 (SELECT e1.* FROM events e1
3212 ON e1.location = e2.location
3213 AND e1.sequence < e2.sequence
3214 WHERE e2.sequence is NULL
3221 =item Value: ( 'update' | 'shared' )
3225 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT