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: $result_class
1120 An accessor for the class to use when creating row objects. Defaults to
1121 C<< result_source->result_class >> - which in most cases is the name of the
1122 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1124 Note that changing the result_class will also remove any components
1125 that were originally loaded in the source class via
1126 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1127 in the original source class will not run.
1132 my ($self, $result_class) = @_;
1133 if ($result_class) {
1134 $self->ensure_class_loaded($result_class);
1135 $self->_result_class($result_class);
1137 $self->_result_class;
1144 =item Arguments: $cond, \%attrs??
1146 =item Return Value: $count
1150 Performs an SQL C<COUNT> with the same query as the resultset was built
1151 with to find the number of elements. If passed arguments, does a search
1152 on the resultset and counts the results of that.
1154 Note: When using C<count> with C<group_by>, L<DBIx::Class> emulates C<GROUP BY>
1155 using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
1156 not support C<DISTINCT> with multiple columns. If you are using such a
1157 database, you should only use columns from the main table in your C<group_by>
1164 return $self->search(@_)->count if @_ and defined $_[0];
1165 return scalar @{ $self->get_cache } if $self->get_cache;
1166 my $count = $self->_count;
1167 return 0 unless $count;
1169 # need to take offset from resolved attrs
1171 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1172 $count = $self->{attrs}{rows} if
1173 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1174 $count = 0 if ($count < 0);
1178 sub _count { # Separated out so pager can get the full count
1180 my $select = { count => '*' };
1182 my $attrs = { %{$self->_resolved_attrs} };
1183 if (my $group_by = delete $attrs->{group_by}) {
1184 delete $attrs->{having};
1185 my @distinct = (ref $group_by ? @$group_by : ($group_by));
1186 # todo: try CONCAT for multi-column pk
1187 my @pk = $self->result_source->primary_columns;
1189 my $alias = $attrs->{alias};
1190 foreach my $column (@distinct) {
1191 if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
1192 @distinct = ($column);
1198 $select = { count => { distinct => \@distinct } };
1201 $attrs->{select} = $select;
1202 $attrs->{as} = [qw/count/];
1204 # offset, order by and page are not needed to count. record_filter is cdbi
1205 delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
1207 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1208 my ($count) = $tmp_rs->cursor->next;
1216 =head2 count_literal
1220 =item Arguments: $sql_fragment, @bind_values
1222 =item Return Value: $count
1226 Counts the results in a literal query. Equivalent to calling L</search_literal>
1227 with the passed arguments, then L</count>.
1231 sub count_literal { shift->search_literal(@_)->count; }
1237 =item Arguments: none
1239 =item Return Value: @objects
1243 Returns all elements in the resultset. Called implicitly if the resultset
1244 is returned in list context.
1251 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1254 return @{ $self->get_cache } if $self->get_cache;
1258 # TODO: don't call resolve here
1259 if (keys %{$self->_resolved_attrs->{collapse}}) {
1260 # if ($self->{attrs}{prefetch}) {
1261 # Using $self->cursor->all is really just an optimisation.
1262 # If we're collapsing has_many prefetches it probably makes
1263 # very little difference, and this is cleaner than hacking
1264 # _construct_object to survive the approach
1265 my @row = $self->cursor->next;
1267 push(@obj, $self->_construct_object(@row));
1268 @row = (exists $self->{stashed_row}
1269 ? @{delete $self->{stashed_row}}
1270 : $self->cursor->next);
1273 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1276 $self->set_cache(\@obj) if $self->{attrs}{cache};
1284 =item Arguments: none
1286 =item Return Value: $self
1290 Resets the resultset's cursor, so you can iterate through the elements again.
1296 delete $self->{_attrs} if exists $self->{_attrs};
1297 $self->{all_cache_position} = 0;
1298 $self->cursor->reset;
1306 =item Arguments: none
1308 =item Return Value: $object?
1312 Resets the resultset and returns an object for the first result (if the
1313 resultset returns anything).
1318 return $_[0]->reset->next;
1321 # _cond_for_update_delete
1323 # update/delete require the condition to be modified to handle
1324 # the differing SQL syntax available. This transforms the $self->{cond}
1325 # appropriately, returning the new condition.
1327 sub _cond_for_update_delete {
1328 my ($self, $full_cond) = @_;
1331 $full_cond ||= $self->{cond};
1332 # No-op. No condition, we're updating/deleting everything
1333 return $cond unless ref $full_cond;
1335 if (ref $full_cond eq 'ARRAY') {
1339 foreach my $key (keys %{$_}) {
1341 $hash{$1} = $_->{$key};
1347 elsif (ref $full_cond eq 'HASH') {
1348 if ((keys %{$full_cond})[0] eq '-and') {
1351 my @cond = @{$full_cond->{-and}};
1352 for (my $i = 0; $i < @cond; $i++) {
1353 my $entry = $cond[$i];
1356 if (ref $entry eq 'HASH') {
1357 $hash = $self->_cond_for_update_delete($entry);
1360 $entry =~ /([^.]+)$/;
1361 $hash->{$1} = $cond[++$i];
1364 push @{$cond->{-and}}, $hash;
1368 foreach my $key (keys %{$full_cond}) {
1370 $cond->{$1} = $full_cond->{$key};
1375 $self->throw_exception(
1376 "Can't update/delete on resultset with condition unless hash or array"
1388 =item Arguments: \%values
1390 =item Return Value: $storage_rv
1394 Sets the specified columns in the resultset to the supplied values in a
1395 single query. Return value will be true if the update succeeded or false
1396 if no records were updated; exact type of success value is storage-dependent.
1401 my ($self, $values) = @_;
1402 $self->throw_exception("Values for update must be a hash")
1403 unless ref $values eq 'HASH';
1405 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1406 . ' on joined resultsets, and may affect rows well outside of the'
1407 . ' contents of $rs. Use at your own risk' )
1408 if ( $self->{attrs}{seen_join} );
1410 my $cond = $self->_cond_for_update_delete;
1412 return $self->result_source->storage->update(
1413 $self->result_source, $values, $cond
1421 =item Arguments: \%values
1423 =item Return Value: 1
1427 Fetches all objects and updates them one at a time. Note that C<update_all>
1428 will run DBIC cascade triggers, while L</update> will not.
1433 my ($self, $values) = @_;
1434 $self->throw_exception("Values for update must be a hash")
1435 unless ref $values eq 'HASH';
1436 foreach my $obj ($self->all) {
1437 $obj->set_columns($values)->update;
1446 =item Arguments: none
1448 =item Return Value: 1
1452 Deletes the contents of the resultset from its result source. Note that this
1453 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1454 to run. See also L<DBIx::Class::Row/delete>.
1456 delete may not generate correct SQL for a query with joins or a resultset
1457 chained from a related resultset. In this case it will generate a warning:-
1459 WARNING! Currently $rs->delete() does not generate proper SQL on
1460 joined resultsets, and may delete rows well outside of the contents
1461 of $rs. Use at your own risk
1463 In these cases you may find that delete_all is more appropriate, or you
1464 need to respecify your query in a way that can be expressed without a join.
1470 $self->throw_exception("Delete should not be passed any arguments")
1472 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1473 . ' on joined resultsets, and may delete rows well outside of the'
1474 . ' contents of $rs. Use at your own risk' )
1475 if ( $self->{attrs}{seen_join} );
1476 my $cond = $self->_cond_for_update_delete;
1478 $self->result_source->storage->delete($self->result_source, $cond);
1486 =item Arguments: none
1488 =item Return Value: 1
1492 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1493 will run DBIC cascade triggers, while L</delete> will not.
1499 $_->delete for $self->all;
1507 =item Arguments: \@data;
1511 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1512 For the arrayref of hashrefs style each hashref should be a structure suitable
1513 forsubmitting to a $resultset->create(...) method.
1515 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1516 to insert the data, as this is a faster method.
1518 Otherwise, each set of data is inserted into the database using
1519 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1520 objects is returned.
1522 Example: Assuming an Artist Class that has many CDs Classes relating:
1524 my $Artist_rs = $schema->resultset("Artist");
1526 ## Void Context Example
1527 $Artist_rs->populate([
1528 { artistid => 4, name => 'Manufactured Crap', cds => [
1529 { title => 'My First CD', year => 2006 },
1530 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1533 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1534 { title => 'My parents sold me to a record company' ,year => 2005 },
1535 { title => 'Why Am I So Ugly?', year => 2006 },
1536 { title => 'I Got Surgery and am now Popular', year => 2007 }
1541 ## Array Context Example
1542 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1543 { name => "Artist One"},
1544 { name => "Artist Two"},
1545 { name => "Artist Three", cds=> [
1546 { title => "First CD", year => 2007},
1547 { title => "Second CD", year => 2008},
1551 print $ArtistOne->name; ## response is 'Artist One'
1552 print $ArtistThree->cds->count ## reponse is '2'
1554 For the arrayref of arrayrefs style, the first element should be a list of the
1555 fieldsnames to which the remaining elements are rows being inserted. For
1558 $Arstist_rs->populate([
1559 [qw/artistid name/],
1560 [100, 'A Formally Unknown Singer'],
1561 [101, 'A singer that jumped the shark two albums ago'],
1562 [102, 'An actually cool singer.'],
1565 Please note an important effect on your data when choosing between void and
1566 wantarray context. Since void context goes straight to C<insert_bulk> in
1567 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1568 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1569 create primary keys for you, you will find that your PKs are empty. In this
1570 case you will have to use the wantarray context in order to create those
1576 my $self = shift @_;
1577 my $data = ref $_[0][0] eq 'HASH'
1578 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1579 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1581 if(defined wantarray) {
1583 foreach my $item (@$data) {
1584 push(@created, $self->create($item));
1588 my ($first, @rest) = @$data;
1590 my @names = grep {!ref $first->{$_}} keys %$first;
1591 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1592 my @pks = $self->result_source->primary_columns;
1594 ## do the belongs_to relationships
1595 foreach my $index (0..$#$data) {
1596 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1597 my @ret = $self->populate($data);
1601 foreach my $rel (@rels) {
1602 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1603 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1604 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1605 my $related = $result->result_source->resolve_condition(
1606 $result->result_source->relationship_info($reverse)->{cond},
1611 delete $data->[$index]->{$rel};
1612 $data->[$index] = {%{$data->[$index]}, %$related};
1614 push @names, keys %$related if $index == 0;
1618 ## do bulk insert on current row
1619 my @values = map { [ @$_{@names} ] } @$data;
1621 $self->result_source->storage->insert_bulk(
1622 $self->result_source,
1627 ## do the has_many relationships
1628 foreach my $item (@$data) {
1630 foreach my $rel (@rels) {
1631 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1633 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1634 || $self->throw_exception('Cannot find the relating object.');
1636 my $child = $parent->$rel;
1638 my $related = $child->result_source->resolve_condition(
1639 $parent->result_source->relationship_info($rel)->{cond},
1644 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1645 my @populate = map { {%$_, %$related} } @rows_to_add;
1647 $child->populate( \@populate );
1653 =head2 _normalize_populate_args ($args)
1655 Private method used by L</populate> to normalize its incoming arguments. Factored
1656 out in case you want to subclass and accept new argument structures to the
1657 L</populate> method.
1661 sub _normalize_populate_args {
1662 my ($self, $data) = @_;
1663 my @names = @{shift(@$data)};
1664 my @results_to_create;
1665 foreach my $datum (@$data) {
1666 my %result_to_create;
1667 foreach my $index (0..$#names) {
1668 $result_to_create{$names[$index]} = $$datum[$index];
1670 push @results_to_create, \%result_to_create;
1672 return \@results_to_create;
1679 =item Arguments: none
1681 =item Return Value: $pager
1685 Return Value a L<Data::Page> object for the current resultset. Only makes
1686 sense for queries with a C<page> attribute.
1688 To get the full count of entries for a paged resultset, call
1689 C<total_entries> on the L<Data::Page> object.
1695 my $attrs = $self->{attrs};
1696 $self->throw_exception("Can't create pager for non-paged rs")
1697 unless $self->{attrs}{page};
1698 $attrs->{rows} ||= 10;
1699 return $self->{pager} ||= Data::Page->new(
1700 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1707 =item Arguments: $page_number
1709 =item Return Value: $rs
1713 Returns a resultset for the $page_number page of the resultset on which page
1714 is called, where each page contains a number of rows equal to the 'rows'
1715 attribute set on the resultset (10 by default).
1720 my ($self, $page) = @_;
1721 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1728 =item Arguments: \%vals
1730 =item Return Value: $rowobject
1734 Creates a new row object in the resultset's result class and returns
1735 it. The row is not inserted into the database at this point, call
1736 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1737 will tell you whether the row object has been inserted or not.
1739 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1744 my ($self, $values) = @_;
1745 $self->throw_exception( "new_result needs a hash" )
1746 unless (ref $values eq 'HASH');
1749 my $alias = $self->{attrs}{alias};
1752 defined $self->{cond}
1753 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1755 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1756 $new{-from_resultset} = [ keys %new ] if keys %new;
1758 $self->throw_exception(
1759 "Can't abstract implicit construct, condition not a hash"
1760 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1762 my $collapsed_cond = (
1764 ? $self->_collapse_cond($self->{cond})
1768 # precendence must be given to passed values over values inherited from
1769 # the cond, so the order here is important.
1770 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1771 while( my($col,$value) = each %implied ){
1772 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1773 $new{$col} = $value->{'='};
1776 $new{$col} = $value if $self->_is_deterministic_value($value);
1782 %{ $self->_remove_alias($values, $alias) },
1783 -source_handle => $self->_source_handle,
1784 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1787 return $self->result_class->new(\%new);
1790 # _is_deterministic_value
1792 # Make an effor to strip non-deterministic values from the condition,
1793 # to make sure new_result chokes less
1795 sub _is_deterministic_value {
1798 my $ref_type = ref $value;
1799 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1800 return 1 if Scalar::Util::blessed($value);
1806 # Recursively collapse the condition.
1808 sub _collapse_cond {
1809 my ($self, $cond, $collapsed) = @_;
1813 if (ref $cond eq 'ARRAY') {
1814 foreach my $subcond (@$cond) {
1815 next unless ref $subcond; # -or
1816 # warn "ARRAY: " . Dumper $subcond;
1817 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1820 elsif (ref $cond eq 'HASH') {
1821 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1822 foreach my $subcond (@{$cond->{-and}}) {
1823 # warn "HASH: " . Dumper $subcond;
1824 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1828 # warn "LEAF: " . Dumper $cond;
1829 foreach my $col (keys %$cond) {
1830 my $value = $cond->{$col};
1831 $collapsed->{$col} = $value;
1841 # Remove the specified alias from the specified query hash. A copy is made so
1842 # the original query is not modified.
1845 my ($self, $query, $alias) = @_;
1847 my %orig = %{ $query || {} };
1850 foreach my $key (keys %orig) {
1852 $unaliased{$key} = $orig{$key};
1855 $unaliased{$1} = $orig{$key}
1856 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1862 =head2 as_query (EXPERIMENTAL)
1866 =item Arguments: none
1868 =item Return Value: \[ $sql, @bind ]
1872 Returns the SQL query and bind vars associated with the invocant.
1874 This is generally used as the RHS for a subquery.
1876 B<NOTE>: This feature is still experimental.
1880 sub as_query { return shift->cursor->as_query(@_) }
1886 =item Arguments: \%vals, \%attrs?
1888 =item Return Value: $rowobject
1892 my $artist = $schema->resultset('Artist')->find_or_new(
1893 { artist => 'fred' }, { key => 'artists' });
1895 $cd->cd_to_producer->find_or_new({ producer => $producer },
1896 { key => 'primary });
1898 Find an existing record from this resultset, based on its primary
1899 key, or a unique constraint. If none exists, instantiate a new result
1900 object and return it. The object will not be saved into your storage
1901 until you call L<DBIx::Class::Row/insert> on it.
1903 You most likely want this method when looking for existing rows using
1904 a unique constraint that is not the primary key, or looking for
1907 If you want objects to be saved immediately, use L</find_or_create> instead.
1909 B<Note>: C<find_or_new> is probably not what you want when creating a
1910 new row in a table that uses primary keys supplied by the
1911 database. Passing in a primary key column with a value of I<undef>
1912 will cause L</find> to attempt to search for a row with a value of
1919 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1920 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1921 my $exists = $self->find($hash, $attrs);
1922 return defined $exists ? $exists : $self->new_result($hash);
1929 =item Arguments: \%vals
1931 =item Return Value: a L<DBIx::Class::Row> $object
1935 Attempt to create a single new row or a row with multiple related rows
1936 in the table represented by the resultset (and related tables). This
1937 will not check for duplicate rows before inserting, use
1938 L</find_or_create> to do that.
1940 To create one row for this resultset, pass a hashref of key/value
1941 pairs representing the columns of the table and the values you wish to
1942 store. If the appropriate relationships are set up, foreign key fields
1943 can also be passed an object representing the foreign row, and the
1944 value will be set to its primary key.
1946 To create related objects, pass a hashref for the value if the related
1947 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1948 and use the name of the relationship as the key. (NOT the name of the field,
1949 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1950 of hashrefs containing the data for each of the rows to create in the foreign
1951 tables, again using the relationship name as the key.
1953 Instead of hashrefs of plain related data (key/value pairs), you may
1954 also pass new or inserted objects. New objects (not inserted yet, see
1955 L</new>), will be inserted into their appropriate tables.
1957 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1959 Example of creating a new row.
1961 $person_rs->create({
1962 name=>"Some Person",
1963 email=>"somebody@someplace.com"
1966 Example of creating a new row and also creating rows in a related C<has_many>
1967 or C<has_one> resultset. Note Arrayref.
1970 { artistid => 4, name => 'Manufactured Crap', cds => [
1971 { title => 'My First CD', year => 2006 },
1972 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1977 Example of creating a new row and also creating a row in a related
1978 C<belongs_to>resultset. Note Hashref.
1981 title=>"Music for Silly Walks",
1984 name=>"Silly Musician",
1991 my ($self, $attrs) = @_;
1992 $self->throw_exception( "create needs a hashref" )
1993 unless ref $attrs eq 'HASH';
1994 return $self->new_result($attrs)->insert;
1997 =head2 find_or_create
2001 =item Arguments: \%vals, \%attrs?
2003 =item Return Value: $rowobject
2007 $cd->cd_to_producer->find_or_create({ producer => $producer },
2008 { key => 'primary });
2010 Tries to find a record based on its primary key or unique constraints; if none
2011 is found, creates one and returns that instead.
2013 my $cd = $schema->resultset('CD')->find_or_create({
2015 artist => 'Massive Attack',
2016 title => 'Mezzanine',
2020 Also takes an optional C<key> attribute, to search by a specific key or unique
2021 constraint. For example:
2023 my $cd = $schema->resultset('CD')->find_or_create(
2025 artist => 'Massive Attack',
2026 title => 'Mezzanine',
2028 { key => 'cd_artist_title' }
2031 B<Note>: Because find_or_create() reads from the database and then
2032 possibly inserts based on the result, this method is subject to a race
2033 condition. Another process could create a record in the table after
2034 the find has completed and before the create has started. To avoid
2035 this problem, use find_or_create() inside a transaction.
2037 B<Note>: C<find_or_create> is probably not what you want when creating
2038 a new row in a table that uses primary keys supplied by the
2039 database. Passing in a primary key column with a value of I<undef>
2040 will cause L</find> to attempt to search for a row with a value of
2043 See also L</find> and L</update_or_create>. For information on how to declare
2044 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2048 sub find_or_create {
2050 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2051 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2052 my $exists = $self->find($hash, $attrs);
2053 return defined $exists ? $exists : $self->create($hash);
2056 =head2 update_or_create
2060 =item Arguments: \%col_values, { key => $unique_constraint }?
2062 =item Return Value: $rowobject
2066 $resultset->update_or_create({ col => $val, ... });
2068 First, searches for an existing row matching one of the unique constraints
2069 (including the primary key) on the source of this resultset. If a row is
2070 found, updates it with the other given column values. Otherwise, creates a new
2073 Takes an optional C<key> attribute to search on a specific unique constraint.
2076 # In your application
2077 my $cd = $schema->resultset('CD')->update_or_create(
2079 artist => 'Massive Attack',
2080 title => 'Mezzanine',
2083 { key => 'cd_artist_title' }
2086 $cd->cd_to_producer->update_or_create({
2087 producer => $producer,
2094 If no C<key> is specified, it searches on all unique constraints defined on the
2095 source, including the primary key.
2097 If the C<key> is specified as C<primary>, it searches only on the primary key.
2099 See also L</find> and L</find_or_create>. For information on how to declare
2100 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2102 B<Note>: C<update_or_create> is probably not what you want when
2103 looking for a row in a table that uses primary keys supplied by the
2104 database, unless you actually have a key value. Passing in a primary
2105 key column with a value of I<undef> will cause L</find> to attempt to
2106 search for a row with a value of I<NULL>.
2110 sub update_or_create {
2112 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2113 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2115 my $row = $self->find($cond, $attrs);
2117 $row->update($cond);
2121 return $self->create($cond);
2124 =head2 update_or_new
2128 =item Arguments: \%col_values, { key => $unique_constraint }?
2130 =item Return Value: $rowobject
2134 $resultset->update_or_new({ col => $val, ... });
2136 First, searches for an existing row matching one of the unique constraints
2137 (including the primary key) on the source of this resultset. If a row is
2138 found, updates it with the other given column values. Otherwise, instantiate
2139 a new result object and return it. The object will not be saved into your storage
2140 until you call L<DBIx::Class::Row/insert> on it.
2142 Takes an optional C<key> attribute to search on a specific unique constraint.
2145 # In your application
2146 my $cd = $schema->resultset('CD')->update_or_new(
2148 artist => 'Massive Attack',
2149 title => 'Mezzanine',
2152 { key => 'cd_artist_title' }
2155 if ($cd->in_storage) {
2156 # the cd was updated
2159 # the cd is not yet in the database, let's insert it
2163 See also L</find>, L</find_or_create> and L<find_or_new>.
2169 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2170 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2172 my $row = $self->find( $cond, $attrs );
2173 if ( defined $row ) {
2174 $row->update($cond);
2178 return $self->new_result($cond);
2185 =item Arguments: none
2187 =item Return Value: \@cache_objects?
2191 Gets the contents of the cache for the resultset, if the cache is set.
2193 The cache is populated either by using the L</prefetch> attribute to
2194 L</search> or by calling L</set_cache>.
2206 =item Arguments: \@cache_objects
2208 =item Return Value: \@cache_objects
2212 Sets the contents of the cache for the resultset. Expects an arrayref
2213 of objects of the same class as those produced by the resultset. Note that
2214 if the cache is set the resultset will return the cached objects rather
2215 than re-querying the database even if the cache attr is not set.
2217 The contents of the cache can also be populated by using the
2218 L</prefetch> attribute to L</search>.
2223 my ( $self, $data ) = @_;
2224 $self->throw_exception("set_cache requires an arrayref")
2225 if defined($data) && (ref $data ne 'ARRAY');
2226 $self->{all_cache} = $data;
2233 =item Arguments: none
2235 =item Return Value: []
2239 Clears the cache for the resultset.
2244 shift->set_cache(undef);
2247 =head2 related_resultset
2251 =item Arguments: $relationship_name
2253 =item Return Value: $resultset
2257 Returns a related resultset for the supplied relationship name.
2259 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2263 sub related_resultset {
2264 my ($self, $rel) = @_;
2266 $self->{related_resultsets} ||= {};
2267 return $self->{related_resultsets}{$rel} ||= do {
2268 my $rel_obj = $self->result_source->relationship_info($rel);
2270 $self->throw_exception(
2271 "search_related: result source '" . $self->result_source->source_name .
2272 "' has no such relationship $rel")
2275 my ($from,$seen) = $self->_resolve_from($rel);
2277 my $join_count = $seen->{$rel};
2278 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2280 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2281 my %attrs = %{$self->{attrs}||{}};
2282 delete @attrs{qw(result_class alias)};
2286 if (my $cache = $self->get_cache) {
2287 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2288 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2293 my $rel_source = $self->result_source->related_source($rel);
2297 # The reason we do this now instead of passing the alias to the
2298 # search_rs below is that if you wrap/overload resultset on the
2299 # source you need to know what alias it's -going- to have for things
2300 # to work sanely (e.g. RestrictWithObject wants to be able to add
2301 # extra query restrictions, and these may need to be $alias.)
2303 my $attrs = $rel_source->resultset_attributes;
2304 local $attrs->{alias} = $alias;
2306 $rel_source->resultset
2314 where => $self->{cond},
2319 $new->set_cache($new_cache) if $new_cache;
2324 =head2 current_source_alias
2328 =item Arguments: none
2330 =item Return Value: $source_alias
2334 Returns the current table alias for the result source this resultset is built
2335 on, that will be used in the SQL query. Usually it is C<me>.
2337 Currently the source alias that refers to the result set returned by a
2338 L</search>/L</find> family method depends on how you got to the resultset: it's
2339 C<me> by default, but eg. L</search_related> aliases it to the related result
2340 source name (and keeps C<me> referring to the original result set). The long
2341 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2342 (and make this method unnecessary).
2344 Thus it's currently necessary to use this method in predefined queries (see
2345 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2346 source alias of the current result set:
2348 # in a result set class
2350 my ($self, $user) = @_;
2352 my $me = $self->current_source_alias;
2354 return $self->search(
2355 "$me.modified" => $user->id,
2361 sub current_source_alias {
2364 return ($self->{attrs} || {})->{alias} || 'me';
2368 my ($self, $extra_join) = @_;
2369 my $source = $self->result_source;
2370 my $attrs = $self->{attrs};
2372 my $from = $attrs->{from}
2373 || [ { $attrs->{alias} => $source->from } ];
2375 my $seen = { %{$attrs->{seen_join}||{}} };
2377 my $join = ($attrs->{join}
2378 ? [ $attrs->{join}, $extra_join ]
2381 # we need to take the prefetch the attrs into account before we
2382 # ->resolve_join as otherwise they get lost - captainL
2383 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2387 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2390 return ($from,$seen);
2393 sub _resolved_attrs {
2395 return $self->{_attrs} if $self->{_attrs};
2397 my $attrs = { %{ $self->{attrs} || {} } };
2398 my $source = $self->result_source;
2399 my $alias = $attrs->{alias};
2401 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2404 # build columns (as long as select isn't set) into a set of as/select hashes
2405 unless ( $attrs->{select} ) {
2407 ( ref($_) eq 'HASH' )
2411 /^\Q${alias}.\E(.+)$/
2422 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2424 # add the additional columns on
2425 foreach ( 'include_columns', '+columns' ) {
2426 push @colbits, map {
2427 ( ref($_) eq 'HASH' )
2429 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2430 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2433 # start with initial select items
2434 if ( $attrs->{select} ) {
2436 ( ref $attrs->{select} eq 'ARRAY' )
2437 ? [ @{ $attrs->{select} } ]
2438 : [ $attrs->{select} ];
2442 ref $attrs->{as} eq 'ARRAY'
2443 ? [ @{ $attrs->{as} } ]
2446 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2451 # otherwise we intialise select & as to empty
2452 $attrs->{select} = [];
2456 # now add colbits to select/as
2457 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2458 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2461 if ( $adds = delete $attrs->{'+select'} ) {
2462 $adds = [$adds] unless ref $adds eq 'ARRAY';
2464 @{ $attrs->{select} },
2465 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2468 if ( $adds = delete $attrs->{'+as'} ) {
2469 $adds = [$adds] unless ref $adds eq 'ARRAY';
2470 push( @{ $attrs->{as} }, @$adds );
2473 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2475 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2476 my $join = delete $attrs->{join} || {};
2478 if ( defined $attrs->{prefetch} ) {
2479 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2483 $attrs->{from} = # have to copy here to avoid corrupting the original
2485 @{ $attrs->{from} },
2486 $source->resolve_join(
2487 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2493 $attrs->{group_by} ||= $attrs->{select}
2494 if delete $attrs->{distinct};
2495 if ( $attrs->{order_by} ) {
2496 $attrs->{order_by} = (
2497 ref( $attrs->{order_by} ) eq 'ARRAY'
2498 ? [ @{ $attrs->{order_by} } ]
2499 : [ $attrs->{order_by} ]
2503 $attrs->{order_by} = [];
2506 my $collapse = $attrs->{collapse} || {};
2507 if ( my $prefetch = delete $attrs->{prefetch} ) {
2508 $prefetch = $self->_merge_attr( {}, $prefetch );
2510 my $seen = { %{ $attrs->{seen_join} || {} } };
2511 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2513 # bring joins back to level of current class
2515 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2516 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2517 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2519 push( @{ $attrs->{order_by} }, @pre_order );
2521 $attrs->{collapse} = $collapse;
2523 if ( $attrs->{page} ) {
2524 $attrs->{offset} ||= 0;
2525 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2528 return $self->{_attrs} = $attrs;
2532 my ($self, $attr) = @_;
2534 if (ref $attr eq 'HASH') {
2535 return $self->_rollout_hash($attr);
2536 } elsif (ref $attr eq 'ARRAY') {
2537 return $self->_rollout_array($attr);
2543 sub _rollout_array {
2544 my ($self, $attr) = @_;
2547 foreach my $element (@{$attr}) {
2548 if (ref $element eq 'HASH') {
2549 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2550 } elsif (ref $element eq 'ARRAY') {
2551 # XXX - should probably recurse here
2552 push( @rolled_array, @{$self->_rollout_array($element)} );
2554 push( @rolled_array, $element );
2557 return \@rolled_array;
2561 my ($self, $attr) = @_;
2564 foreach my $key (keys %{$attr}) {
2565 push( @rolled_array, { $key => $attr->{$key} } );
2567 return \@rolled_array;
2570 sub _calculate_score {
2571 my ($self, $a, $b) = @_;
2573 if (ref $b eq 'HASH') {
2574 my ($b_key) = keys %{$b};
2575 if (ref $a eq 'HASH') {
2576 my ($a_key) = keys %{$a};
2577 if ($a_key eq $b_key) {
2578 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2583 return ($a eq $b_key) ? 1 : 0;
2586 if (ref $a eq 'HASH') {
2587 my ($a_key) = keys %{$a};
2588 return ($b eq $a_key) ? 1 : 0;
2590 return ($b eq $a) ? 1 : 0;
2596 my ($self, $orig, $import) = @_;
2598 return $import unless defined($orig);
2599 return $orig unless defined($import);
2601 $orig = $self->_rollout_attr($orig);
2602 $import = $self->_rollout_attr($import);
2605 foreach my $import_element ( @{$import} ) {
2606 # find best candidate from $orig to merge $b_element into
2607 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2608 foreach my $orig_element ( @{$orig} ) {
2609 my $score = $self->_calculate_score( $orig_element, $import_element );
2610 if ($score > $best_candidate->{score}) {
2611 $best_candidate->{position} = $position;
2612 $best_candidate->{score} = $score;
2616 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2618 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2619 push( @{$orig}, $import_element );
2621 my $orig_best = $orig->[$best_candidate->{position}];
2622 # merge orig_best and b_element together and replace original with merged
2623 if (ref $orig_best ne 'HASH') {
2624 $orig->[$best_candidate->{position}] = $import_element;
2625 } elsif (ref $import_element eq 'HASH') {
2626 my ($key) = keys %{$orig_best};
2627 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2630 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2640 $self->_source_handle($_[0]->handle);
2642 $self->_source_handle->resolve;
2646 =head2 throw_exception
2648 See L<DBIx::Class::Schema/throw_exception> for details.
2652 sub throw_exception {
2654 if (ref $self && $self->_source_handle->schema) {
2655 $self->_source_handle->schema->throw_exception(@_)
2662 # XXX: FIXME: Attributes docs need clearing up
2666 Attributes are used to refine a ResultSet in various ways when
2667 searching for data. They can be passed to any method which takes an
2668 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2671 These are in no particular order:
2677 =item Value: ( $order_by | \@order_by | \%order_by )
2681 Which column(s) to order the results by. If a single column name, or
2682 an arrayref of names is supplied, the argument is passed through
2683 directly to SQL. The hashref syntax allows for connection-agnostic
2684 specification of ordering direction:
2686 For descending order:
2688 order_by => { -desc => [qw/col1 col2 col3/] }
2690 For explicit ascending order:
2692 order_by => { -asc => 'col' }
2694 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2695 supported, although you are strongly encouraged to use the hashref
2696 syntax as outlined above.
2702 =item Value: \@columns
2706 Shortcut to request a particular set of columns to be retrieved. Each
2707 column spec may be a string (a table column name), or a hash (in which
2708 case the key is the C<as> value, and the value is used as the C<select>
2709 expression). Adds C<me.> onto the start of any column without a C<.> in
2710 it and sets C<select> from that, then auto-populates C<as> from
2711 C<select> as normal. (You may also use the C<cols> attribute, as in
2712 earlier versions of DBIC.)
2718 =item Value: \@columns
2722 Indicates additional columns to be selected from storage. Works the same
2723 as L</columns> but adds columns to the selection. (You may also use the
2724 C<include_columns> attribute, as in earlier versions of DBIC). For
2727 $schema->resultset('CD')->search(undef, {
2728 '+columns' => ['artist.name'],
2732 would return all CDs and include a 'name' column to the information
2733 passed to object inflation. Note that the 'artist' is the name of the
2734 column (or relationship) accessor, and 'name' is the name of the column
2735 accessor in the related table.
2737 =head2 include_columns
2741 =item Value: \@columns
2745 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2751 =item Value: \@select_columns
2755 Indicates which columns should be selected from the storage. You can use
2756 column names, or in the case of RDBMS back ends, function or stored procedure
2759 $rs = $schema->resultset('Employee')->search(undef, {
2762 { count => 'employeeid' },
2767 When you use function/stored procedure names and do not supply an C<as>
2768 attribute, the column names returned are storage-dependent. E.g. MySQL would
2769 return a column named C<count(employeeid)> in the above example.
2775 Indicates additional columns to be selected from storage. Works the same as
2776 L</select> but adds columns to the selection.
2784 Indicates additional column names for those added via L</+select>. See L</as>.
2792 =item Value: \@inflation_names
2796 Indicates column names for object inflation. That is, C<as>
2797 indicates the name that the column can be accessed as via the
2798 C<get_column> method (or via the object accessor, B<if one already
2799 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2801 The C<as> attribute is used in conjunction with C<select>,
2802 usually when C<select> contains one or more function or stored
2805 $rs = $schema->resultset('Employee')->search(undef, {
2808 { count => 'employeeid' }
2810 as => ['name', 'employee_count'],
2813 my $employee = $rs->first(); # get the first Employee
2815 If the object against which the search is performed already has an accessor
2816 matching a column name specified in C<as>, the value can be retrieved using
2817 the accessor as normal:
2819 my $name = $employee->name();
2821 If on the other hand an accessor does not exist in the object, you need to
2822 use C<get_column> instead:
2824 my $employee_count = $employee->get_column('employee_count');
2826 You can create your own accessors if required - see
2827 L<DBIx::Class::Manual::Cookbook> for details.
2829 Please note: This will NOT insert an C<AS employee_count> into the SQL
2830 statement produced, it is used for internal access only. Thus
2831 attempting to use the accessor in an C<order_by> clause or similar
2832 will fail miserably.
2834 To get around this limitation, you can supply literal SQL to your
2835 C<select> attibute that contains the C<AS alias> text, eg:
2837 select => [\'myfield AS alias']
2843 =item Value: ($rel_name | \@rel_names | \%rel_names)
2847 Contains a list of relationships that should be joined for this query. For
2850 # Get CDs by Nine Inch Nails
2851 my $rs = $schema->resultset('CD')->search(
2852 { 'artist.name' => 'Nine Inch Nails' },
2853 { join => 'artist' }
2856 Can also contain a hash reference to refer to the other relation's relations.
2859 package MyApp::Schema::Track;
2860 use base qw/DBIx::Class/;
2861 __PACKAGE__->table('track');
2862 __PACKAGE__->add_columns(qw/trackid cd position title/);
2863 __PACKAGE__->set_primary_key('trackid');
2864 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2867 # In your application
2868 my $rs = $schema->resultset('Artist')->search(
2869 { 'track.title' => 'Teardrop' },
2871 join => { cd => 'track' },
2872 order_by => 'artist.name',
2876 You need to use the relationship (not the table) name in conditions,
2877 because they are aliased as such. The current table is aliased as "me", so
2878 you need to use me.column_name in order to avoid ambiguity. For example:
2880 # Get CDs from 1984 with a 'Foo' track
2881 my $rs = $schema->resultset('CD')->search(
2884 'tracks.name' => 'Foo'
2886 { join => 'tracks' }
2889 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2890 similarly for a third time). For e.g.
2892 my $rs = $schema->resultset('Artist')->search({
2893 'cds.title' => 'Down to Earth',
2894 'cds_2.title' => 'Popular',
2896 join => [ qw/cds cds/ ],
2899 will return a set of all artists that have both a cd with title 'Down
2900 to Earth' and a cd with title 'Popular'.
2902 If you want to fetch related objects from other tables as well, see C<prefetch>
2905 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2911 =item Value: ($rel_name | \@rel_names | \%rel_names)
2915 Contains one or more relationships that should be fetched along with
2916 the main query (when they are accessed afterwards the data will
2917 already be available, without extra queries to the database). This is
2918 useful for when you know you will need the related objects, because it
2919 saves at least one query:
2921 my $rs = $schema->resultset('Tag')->search(
2930 The initial search results in SQL like the following:
2932 SELECT tag.*, cd.*, artist.* FROM tag
2933 JOIN cd ON tag.cd = cd.cdid
2934 JOIN artist ON cd.artist = artist.artistid
2936 L<DBIx::Class> has no need to go back to the database when we access the
2937 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2940 Simple prefetches will be joined automatically, so there is no need
2941 for a C<join> attribute in the above search.
2943 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2944 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2945 with an accessor type of 'single' or 'filter'). A more complex example that
2946 prefetches an artists cds, the tracks on those cds, and the tags associted
2947 with that artist is given below (assuming many-to-many from artists to tags):
2949 my $rs = $schema->resultset('Artist')->search(
2953 { cds => 'tracks' },
2954 { artist_tags => 'tags' }
2960 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2961 attributes will be ignored.
2971 Makes the resultset paged and specifies the page to retrieve. Effectively
2972 identical to creating a non-pages resultset and then calling ->page($page)
2975 If L<rows> attribute is not specified it defualts to 10 rows per page.
2977 When you have a paged resultset, L</count> will only return the number
2978 of rows in the page. To get the total, use the L</pager> and call
2979 C<total_entries> on it.
2989 Specifes the maximum number of rows for direct retrieval or the number of
2990 rows per page if the page attribute or method is used.
2996 =item Value: $offset
3000 Specifies the (zero-based) row number for the first row to be returned, or the
3001 of the first row of the first page if paging is used.
3007 =item Value: \@columns
3011 A arrayref of columns to group by. Can include columns of joined tables.
3013 group_by => [qw/ column1 column2 ... /]
3019 =item Value: $condition
3023 HAVING is a select statement attribute that is applied between GROUP BY and
3024 ORDER BY. It is applied to the after the grouping calculations have been
3027 having => { 'count(employee)' => { '>=', 100 } }
3033 =item Value: (0 | 1)
3037 Set to 1 to group by all columns.
3043 Adds to the WHERE clause.
3045 # only return rows WHERE deleted IS NULL for all searches
3046 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3048 Can be overridden by passing C<{ where => undef }> as an attribute
3055 Set to 1 to cache search results. This prevents extra SQL queries if you
3056 revisit rows in your ResultSet:
3058 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3060 while( my $artist = $resultset->next ) {
3064 $rs->first; # without cache, this would issue a query
3066 By default, searches are not cached.
3068 For more examples of using these attributes, see
3069 L<DBIx::Class::Manual::Cookbook>.
3075 =item Value: \@from_clause
3079 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3080 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3083 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3085 C<join> will usually do what you need and it is strongly recommended that you
3086 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3087 And we really do mean "cannot", not just tried and failed. Attempting to use
3088 this because you're having problems with C<join> is like trying to use x86
3089 ASM because you've got a syntax error in your C. Trust us on this.
3091 Now, if you're still really, really sure you need to use this (and if you're
3092 not 100% sure, ask the mailing list first), here's an explanation of how this
3095 The syntax is as follows -
3098 { <alias1> => <table1> },
3100 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3101 [], # nested JOIN (optional)
3102 { <table1.column1> => <table2.column2>, ... (more conditions) },
3104 # More of the above [ ] may follow for additional joins
3111 ON <table1.column1> = <table2.column2>
3112 <more joins may follow>
3114 An easy way to follow the examples below is to remember the following:
3116 Anything inside "[]" is a JOIN
3117 Anything inside "{}" is a condition for the enclosing JOIN
3119 The following examples utilize a "person" table in a family tree application.
3120 In order to express parent->child relationships, this table is self-joined:
3122 # Person->belongs_to('father' => 'Person');
3123 # Person->belongs_to('mother' => 'Person');
3125 C<from> can be used to nest joins. Here we return all children with a father,
3126 then search against all mothers of those children:
3128 $rs = $schema->resultset('Person')->search(
3131 alias => 'mother', # alias columns in accordance with "from"
3133 { mother => 'person' },
3136 { child => 'person' },
3138 { father => 'person' },
3139 { 'father.person_id' => 'child.father_id' }
3142 { 'mother.person_id' => 'child.mother_id' }
3149 # SELECT mother.* FROM person mother
3152 # JOIN person father
3153 # ON ( father.person_id = child.father_id )
3155 # ON ( mother.person_id = child.mother_id )
3157 The type of any join can be controlled manually. To search against only people
3158 with a father in the person table, we could explicitly use C<INNER JOIN>:
3160 $rs = $schema->resultset('Person')->search(
3163 alias => 'child', # alias columns in accordance with "from"
3165 { child => 'person' },
3167 { father => 'person', -join_type => 'inner' },
3168 { 'father.id' => 'child.father_id' }
3175 # SELECT child.* FROM person child
3176 # INNER JOIN person father ON child.father_id = father.id
3178 If you need to express really complex joins or you need a subselect, you
3179 can supply literal SQL to C<from> via a scalar reference. In this case
3180 the contents of the scalar will replace the table name asscoiated with the
3183 WARNING: This technique might very well not work as expected on chained
3184 searches - you have been warned.
3186 # Assuming the Event resultsource is defined as:
3188 MySchema::Event->add_columns (
3191 is_auto_increment => 1,
3200 MySchema::Event->set_primary_key ('sequence');
3202 # This will get back the latest event for every location. The column
3203 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3204 # combo to limit the resultset
3206 $rs = $schema->resultset('Event');
3207 $table = $rs->result_source->name;
3208 $latest = $rs->search (
3211 (SELECT e1.* FROM $table e1
3213 ON e1.location = e2.location
3214 AND e1.sequence < e2.sequence
3215 WHERE e2.sequence is NULL
3220 # Equivalent SQL (with the DBIC chunks added):
3222 SELECT me.sequence, me.location, me.type FROM
3223 (SELECT e1.* FROM events e1
3225 ON e1.location = e2.location
3226 AND e1.sequence < e2.sequence
3227 WHERE e2.sequence is NULL
3234 =item Value: ( 'update' | 'shared' )
3238 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT