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 bind/) {
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 $collapsed = $self->_collapse_query($subquery, $collapsed);
802 elsif (ref $query eq 'HASH') {
803 if (keys %$query and (keys %$query)[0] eq '-and') {
804 foreach my $subquery (@{$query->{-and}}) {
805 $collapsed = $self->_collapse_query($subquery, $collapsed);
809 foreach my $col (keys %$query) {
810 my $value = $query->{$col};
811 $collapsed->{$col}{$value}++;
823 =item Arguments: $cond?
825 =item Return Value: $resultsetcolumn
829 my $max_length = $rs->get_column('length')->max;
831 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
836 my ($self, $column) = @_;
837 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
845 =item Arguments: $cond, \%attrs?
847 =item Return Value: $resultset (scalar context), @row_objs (list context)
851 # WHERE title LIKE '%blue%'
852 $cd_rs = $rs->search_like({ title => '%blue%'});
854 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
855 that this is simply a convenience method retained for ex Class::DBI users.
856 You most likely want to use L</search> with specific operators.
858 For more information, see L<DBIx::Class::Manual::Cookbook>.
860 This method is deprecated and will be removed in 0.09. Use L</search()>
861 instead. An example conversion is:
863 ->search_like({ foo => 'bar' });
867 ->search({ foo => { like => 'bar' } });
874 'search_like() is deprecated and will be removed in 0.09.',
875 'Instead use ->search({ x => { -like => "y%" } })',
876 '(note the outer pair of {}s - they are important!)'
878 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
879 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
880 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
881 return $class->search($query, { %$attrs });
888 =item Arguments: $first, $last
890 =item Return Value: $resultset (scalar context), @row_objs (list context)
894 Returns a resultset or object list representing a subset of elements from the
895 resultset slice is called on. Indexes are from 0, i.e., to get the first
898 my ($one, $two, $three) = $rs->slice(0, 2);
903 my ($self, $min, $max) = @_;
904 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
905 $attrs->{offset} = $self->{attrs}{offset} || 0;
906 $attrs->{offset} += $min;
907 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
908 return $self->search(undef(), $attrs);
909 #my $slice = (ref $self)->new($self->result_source, $attrs);
910 #return (wantarray ? $slice->all : $slice);
917 =item Arguments: none
919 =item Return Value: $result?
923 Returns the next element in the resultset (C<undef> is there is none).
925 Can be used to efficiently iterate over records in the resultset:
927 my $rs = $schema->resultset('CD')->search;
928 while (my $cd = $rs->next) {
932 Note that you need to store the resultset object, and call C<next> on it.
933 Calling C<< resultset('Table')->next >> repeatedly will always return the
934 first record from the resultset.
940 if (my $cache = $self->get_cache) {
941 $self->{all_cache_position} ||= 0;
942 return $cache->[$self->{all_cache_position}++];
944 if ($self->{attrs}{cache}) {
945 $self->{all_cache_position} = 1;
946 return ($self->all)[0];
948 if ($self->{stashed_objects}) {
949 my $obj = shift(@{$self->{stashed_objects}});
950 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
954 exists $self->{stashed_row}
955 ? @{delete $self->{stashed_row}}
956 : $self->cursor->next
958 return undef unless (@row);
959 my ($row, @more) = $self->_construct_object(@row);
960 $self->{stashed_objects} = \@more if @more;
964 sub _construct_object {
965 my ($self, @row) = @_;
966 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
967 my @new = $self->result_class->inflate_result($self->result_source, @$info);
968 @new = $self->{_attrs}{record_filter}->(@new)
969 if exists $self->{_attrs}{record_filter};
973 sub _collapse_result {
974 my ($self, $as_proto, $row) = @_;
978 # 'foo' => [ undef, 'foo' ]
979 # 'foo.bar' => [ 'foo', 'bar' ]
980 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
982 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
984 my %collapse = %{$self->{_attrs}{collapse}||{}};
988 # if we're doing collapsing (has_many prefetch) we need to grab records
989 # until the PK changes, so fill @pri_index. if not, we leave it empty so
990 # we know we don't have to bother.
992 # the reason for not using the collapse stuff directly is because if you
993 # had for e.g. two artists in a row with no cds, the collapse info for
994 # both would be NULL (undef) so you'd lose the second artist
996 # store just the index so we can check the array positions from the row
997 # without having to contruct the full hash
999 if (keys %collapse) {
1000 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1001 foreach my $i (0 .. $#construct_as) {
1002 next if defined($construct_as[$i][0]); # only self table
1003 if (delete $pri{$construct_as[$i][1]}) {
1004 push(@pri_index, $i);
1006 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1010 # no need to do an if, it'll be empty if @pri_index is empty anyway
1012 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1016 do { # no need to check anything at the front, we always want the first row
1020 foreach my $this_as (@construct_as) {
1021 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1024 push(@const_rows, \%const);
1026 } until ( # no pri_index => no collapse => drop straight out
1029 do { # get another row, stash it, drop out if different PK
1031 @copy = $self->cursor->next;
1032 $self->{stashed_row} = \@copy;
1034 # last thing in do block, counts as true if anything doesn't match
1036 # check xor defined first for NULL vs. NOT NULL then if one is
1037 # defined the other must be so check string equality
1040 (defined $pri_vals{$_} ^ defined $copy[$_])
1041 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1046 my $alias = $self->{attrs}{alias};
1053 foreach my $const (@const_rows) {
1054 scalar @const_keys or do {
1055 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1057 foreach my $key (@const_keys) {
1060 my @parts = split(/\./, $key);
1062 my $data = $const->{$key};
1063 foreach my $p (@parts) {
1064 $target = $target->[1]->{$p} ||= [];
1066 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1067 # collapsing at this point and on final part
1068 my $pos = $collapse_pos{$cur};
1069 CK: foreach my $ck (@ckey) {
1070 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1071 $collapse_pos{$cur} = $data;
1072 delete @collapse_pos{ # clear all positioning for sub-entries
1073 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1080 if (exists $collapse{$cur}) {
1081 $target = $target->[-1];
1084 $target->[0] = $data;
1086 $info->[0] = $const->{$key};
1094 =head2 result_source
1098 =item Arguments: $result_source?
1100 =item Return Value: $result_source
1104 An accessor for the primary ResultSource object from which this ResultSet
1111 =item Arguments: $result_class?
1113 =item Return Value: $result_class
1117 An accessor for the class to use when creating row objects. Defaults to
1118 C<< result_source->result_class >> - which in most cases is the name of the
1119 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1121 Note that changing the result_class will also remove any components
1122 that were originally loaded in the source class via
1123 L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
1124 in the original source class will not run.
1129 my ($self, $result_class) = @_;
1130 if ($result_class) {
1131 $self->ensure_class_loaded($result_class);
1132 $self->_result_class($result_class);
1134 $self->_result_class;
1141 =item Arguments: $cond, \%attrs??
1143 =item Return Value: $count
1147 Performs an SQL C<COUNT> with the same query as the resultset was built
1148 with to find the number of elements. If passed arguments, does a search
1149 on the resultset and counts the results of that.
1155 return $self->search(@_)->count if @_ and defined $_[0];
1156 return scalar @{ $self->get_cache } if $self->get_cache;
1157 my $count = $self->_count;
1158 return 0 unless $count;
1160 # need to take offset from resolved attrs
1162 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1163 $count = $self->{attrs}{rows} if
1164 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1165 $count = 0 if ($count < 0);
1169 sub _count { # Separated out so pager can get the full count
1171 my $attrs = { %{$self->_resolved_attrs} };
1173 if (my $group_by = $attrs->{group_by}) {
1174 delete $attrs->{order_by};
1176 $attrs->{select} = $group_by;
1177 $attrs->{from} = [ { 'mesub' => (ref $self)->new($self->result_source, $attrs)->cursor->as_query } ];
1178 delete $attrs->{where};
1181 $attrs->{select} = { count => '*' };
1182 $attrs->{as} = [qw/count/];
1184 # offset, order by, group by, where and page are not needed to count. record_filter is cdbi
1185 delete $attrs->{$_} for qw/rows offset order_by group_by page pager record_filter/;
1187 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1188 my ($count) = $tmp_rs->cursor->next;
1196 =head2 count_literal
1200 =item Arguments: $sql_fragment, @bind_values
1202 =item Return Value: $count
1206 Counts the results in a literal query. Equivalent to calling L</search_literal>
1207 with the passed arguments, then L</count>.
1211 sub count_literal { shift->search_literal(@_)->count; }
1217 =item Arguments: none
1219 =item Return Value: @objects
1223 Returns all elements in the resultset. Called implicitly if the resultset
1224 is returned in list context.
1231 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1234 return @{ $self->get_cache } if $self->get_cache;
1238 # TODO: don't call resolve here
1239 if (keys %{$self->_resolved_attrs->{collapse}}) {
1240 # if ($self->{attrs}{prefetch}) {
1241 # Using $self->cursor->all is really just an optimisation.
1242 # If we're collapsing has_many prefetches it probably makes
1243 # very little difference, and this is cleaner than hacking
1244 # _construct_object to survive the approach
1245 my @row = $self->cursor->next;
1247 push(@obj, $self->_construct_object(@row));
1248 @row = (exists $self->{stashed_row}
1249 ? @{delete $self->{stashed_row}}
1250 : $self->cursor->next);
1253 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1256 $self->set_cache(\@obj) if $self->{attrs}{cache};
1264 =item Arguments: none
1266 =item Return Value: $self
1270 Resets the resultset's cursor, so you can iterate through the elements again.
1276 delete $self->{_attrs} if exists $self->{_attrs};
1277 $self->{all_cache_position} = 0;
1278 $self->cursor->reset;
1286 =item Arguments: none
1288 =item Return Value: $object?
1292 Resets the resultset and returns an object for the first result (if the
1293 resultset returns anything).
1298 return $_[0]->reset->next;
1301 # _cond_for_update_delete
1303 # update/delete require the condition to be modified to handle
1304 # the differing SQL syntax available. This transforms the $self->{cond}
1305 # appropriately, returning the new condition.
1307 sub _cond_for_update_delete {
1308 my ($self, $full_cond) = @_;
1311 $full_cond ||= $self->{cond};
1312 # No-op. No condition, we're updating/deleting everything
1313 return $cond unless ref $full_cond;
1315 # Some attributes when present require a subquery
1316 # This might not work on some database (mysql), but...
1317 # it won't work without the subquery either so who cares
1318 if (grep { defined $self->{attrs}{$_} } qw/join seen_join from rows group_by/) {
1320 foreach my $pk ($self->result_source->primary_columns) {
1321 $cond->{$pk} = { IN => $self->get_column($pk)->as_query };
1327 if (ref $full_cond eq 'ARRAY') {
1331 foreach my $key (keys %{$_}) {
1333 $hash{$1} = $_->{$key};
1339 elsif (ref $full_cond eq 'HASH') {
1340 if ((keys %{$full_cond})[0] eq '-and') {
1342 my @cond = @{$full_cond->{-and}};
1343 for (my $i = 0; $i < @cond; $i++) {
1344 my $entry = $cond[$i];
1346 if (ref $entry eq 'HASH') {
1347 $hash = $self->_cond_for_update_delete($entry);
1350 $entry =~ /([^.]+)$/;
1351 $hash->{$1} = $cond[++$i];
1353 push @{$cond->{-and}}, $hash;
1357 foreach my $key (keys %{$full_cond}) {
1359 $cond->{$1} = $full_cond->{$key};
1364 $self->throw_exception("Can't update/delete on resultset with condition unless hash or array");
1375 =item Arguments: \%values
1377 =item Return Value: $storage_rv
1381 Sets the specified columns in the resultset to the supplied values in a
1382 single query. Return value will be true if the update succeeded or false
1383 if no records were updated; exact type of success value is storage-dependent.
1388 my ($self, $values) = @_;
1389 $self->throw_exception("Values for update must be a hash")
1390 unless ref $values eq 'HASH';
1392 my $cond = $self->_cond_for_update_delete;
1394 return $self->result_source->storage->update(
1395 $self->result_source, $values, $cond
1403 =item Arguments: \%values
1405 =item Return Value: 1
1409 Fetches all objects and updates them one at a time. Note that C<update_all>
1410 will run DBIC cascade triggers, while L</update> will not.
1415 my ($self, $values) = @_;
1416 $self->throw_exception("Values for update must be a hash")
1417 unless ref $values eq 'HASH';
1418 foreach my $obj ($self->all) {
1419 $obj->set_columns($values)->update;
1428 =item Arguments: none
1430 =item Return Value: 1
1434 Deletes the contents of the resultset from its result source. Note that this
1435 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1436 to run. See also L<DBIx::Class::Row/delete>.
1438 delete may not generate correct SQL for a query with joins or a resultset
1439 chained from a related resultset. In this case it will generate a warning:-
1441 In these cases you may find that delete_all is more appropriate, or you
1442 need to respecify your query in a way that can be expressed without a join.
1448 $self->throw_exception("Delete should not be passed any arguments")
1451 my $cond = $self->_cond_for_update_delete;
1453 $self->result_source->storage->delete($self->result_source, $cond);
1461 =item Arguments: none
1463 =item Return Value: 1
1467 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1468 will run DBIC cascade triggers, while L</delete> will not.
1474 $_->delete for $self->all;
1482 =item Arguments: \@data;
1486 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1487 For the arrayref of hashrefs style each hashref should be a structure suitable
1488 forsubmitting to a $resultset->create(...) method.
1490 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1491 to insert the data, as this is a faster method.
1493 Otherwise, each set of data is inserted into the database using
1494 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1495 objects is returned.
1497 Example: Assuming an Artist Class that has many CDs Classes relating:
1499 my $Artist_rs = $schema->resultset("Artist");
1501 ## Void Context Example
1502 $Artist_rs->populate([
1503 { artistid => 4, name => 'Manufactured Crap', cds => [
1504 { title => 'My First CD', year => 2006 },
1505 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1508 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1509 { title => 'My parents sold me to a record company' ,year => 2005 },
1510 { title => 'Why Am I So Ugly?', year => 2006 },
1511 { title => 'I Got Surgery and am now Popular', year => 2007 }
1516 ## Array Context Example
1517 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1518 { name => "Artist One"},
1519 { name => "Artist Two"},
1520 { name => "Artist Three", cds=> [
1521 { title => "First CD", year => 2007},
1522 { title => "Second CD", year => 2008},
1526 print $ArtistOne->name; ## response is 'Artist One'
1527 print $ArtistThree->cds->count ## reponse is '2'
1529 For the arrayref of arrayrefs style, the first element should be a list of the
1530 fieldsnames to which the remaining elements are rows being inserted. For
1533 $Arstist_rs->populate([
1534 [qw/artistid name/],
1535 [100, 'A Formally Unknown Singer'],
1536 [101, 'A singer that jumped the shark two albums ago'],
1537 [102, 'An actually cool singer.'],
1540 Please note an important effect on your data when choosing between void and
1541 wantarray context. Since void context goes straight to C<insert_bulk> in
1542 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1543 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1544 create primary keys for you, you will find that your PKs are empty. In this
1545 case you will have to use the wantarray context in order to create those
1551 my $self = shift @_;
1552 my $data = ref $_[0][0] eq 'HASH'
1553 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1554 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1556 if(defined wantarray) {
1558 foreach my $item (@$data) {
1559 push(@created, $self->create($item));
1563 my ($first, @rest) = @$data;
1565 my @names = grep {!ref $first->{$_}} keys %$first;
1566 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1567 my @pks = $self->result_source->primary_columns;
1569 ## do the belongs_to relationships
1570 foreach my $index (0..$#$data) {
1571 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1572 my @ret = $self->populate($data);
1576 foreach my $rel (@rels) {
1577 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1578 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1579 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1580 my $related = $result->result_source->resolve_condition(
1581 $result->result_source->relationship_info($reverse)->{cond},
1586 delete $data->[$index]->{$rel};
1587 $data->[$index] = {%{$data->[$index]}, %$related};
1589 push @names, keys %$related if $index == 0;
1593 ## do bulk insert on current row
1594 my @values = map { [ @$_{@names} ] } @$data;
1596 $self->result_source->storage->insert_bulk(
1597 $self->result_source,
1602 ## do the has_many relationships
1603 foreach my $item (@$data) {
1605 foreach my $rel (@rels) {
1606 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1608 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1609 || $self->throw_exception('Cannot find the relating object.');
1611 my $child = $parent->$rel;
1613 my $related = $child->result_source->resolve_condition(
1614 $parent->result_source->relationship_info($rel)->{cond},
1619 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1620 my @populate = map { {%$_, %$related} } @rows_to_add;
1622 $child->populate( \@populate );
1628 =head2 _normalize_populate_args ($args)
1630 Private method used by L</populate> to normalize its incoming arguments. Factored
1631 out in case you want to subclass and accept new argument structures to the
1632 L</populate> method.
1636 sub _normalize_populate_args {
1637 my ($self, $data) = @_;
1638 my @names = @{shift(@$data)};
1639 my @results_to_create;
1640 foreach my $datum (@$data) {
1641 my %result_to_create;
1642 foreach my $index (0..$#names) {
1643 $result_to_create{$names[$index]} = $$datum[$index];
1645 push @results_to_create, \%result_to_create;
1647 return \@results_to_create;
1654 =item Arguments: none
1656 =item Return Value: $pager
1660 Return Value a L<Data::Page> object for the current resultset. Only makes
1661 sense for queries with a C<page> attribute.
1663 To get the full count of entries for a paged resultset, call
1664 C<total_entries> on the L<Data::Page> object.
1670 my $attrs = $self->{attrs};
1671 $self->throw_exception("Can't create pager for non-paged rs")
1672 unless $self->{attrs}{page};
1673 $attrs->{rows} ||= 10;
1674 return $self->{pager} ||= Data::Page->new(
1675 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1682 =item Arguments: $page_number
1684 =item Return Value: $rs
1688 Returns a resultset for the $page_number page of the resultset on which page
1689 is called, where each page contains a number of rows equal to the 'rows'
1690 attribute set on the resultset (10 by default).
1695 my ($self, $page) = @_;
1696 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1703 =item Arguments: \%vals
1705 =item Return Value: $rowobject
1709 Creates a new row object in the resultset's result class and returns
1710 it. The row is not inserted into the database at this point, call
1711 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1712 will tell you whether the row object has been inserted or not.
1714 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1719 my ($self, $values) = @_;
1720 $self->throw_exception( "new_result needs a hash" )
1721 unless (ref $values eq 'HASH');
1724 my $alias = $self->{attrs}{alias};
1727 defined $self->{cond}
1728 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1730 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1731 $new{-from_resultset} = [ keys %new ] if keys %new;
1733 $self->throw_exception(
1734 "Can't abstract implicit construct, condition not a hash"
1735 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1737 my $collapsed_cond = (
1739 ? $self->_collapse_cond($self->{cond})
1743 # precendence must be given to passed values over values inherited from
1744 # the cond, so the order here is important.
1745 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1746 while( my($col,$value) = each %implied ){
1747 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1748 $new{$col} = $value->{'='};
1751 $new{$col} = $value if $self->_is_deterministic_value($value);
1757 %{ $self->_remove_alias($values, $alias) },
1758 -source_handle => $self->_source_handle,
1759 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1762 return $self->result_class->new(\%new);
1765 # _is_deterministic_value
1767 # Make an effor to strip non-deterministic values from the condition,
1768 # to make sure new_result chokes less
1770 sub _is_deterministic_value {
1773 my $ref_type = ref $value;
1774 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1775 return 1 if Scalar::Util::blessed($value);
1781 # Recursively collapse the condition.
1783 sub _collapse_cond {
1784 my ($self, $cond, $collapsed) = @_;
1788 if (ref $cond eq 'ARRAY') {
1789 foreach my $subcond (@$cond) {
1790 next unless ref $subcond; # -or
1791 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1794 elsif (ref $cond eq 'HASH') {
1795 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1796 foreach my $subcond (@{$cond->{-and}}) {
1797 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1801 foreach my $col (keys %$cond) {
1802 my $value = $cond->{$col};
1803 $collapsed->{$col} = $value;
1813 # Remove the specified alias from the specified query hash. A copy is made so
1814 # the original query is not modified.
1817 my ($self, $query, $alias) = @_;
1819 my %orig = %{ $query || {} };
1822 foreach my $key (keys %orig) {
1824 $unaliased{$key} = $orig{$key};
1827 $unaliased{$1} = $orig{$key}
1828 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1834 =head2 as_query (EXPERIMENTAL)
1838 =item Arguments: none
1840 =item Return Value: \[ $sql, @bind ]
1844 Returns the SQL query and bind vars associated with the invocant.
1846 This is generally used as the RHS for a subquery.
1848 B<NOTE>: This feature is still experimental.
1852 sub as_query { return shift->cursor->as_query(@_) }
1858 =item Arguments: \%vals, \%attrs?
1860 =item Return Value: $rowobject
1864 my $artist = $schema->resultset('Artist')->find_or_new(
1865 { artist => 'fred' }, { key => 'artists' });
1867 $cd->cd_to_producer->find_or_new({ producer => $producer },
1868 { key => 'primary });
1870 Find an existing record from this resultset, based on its primary
1871 key, or a unique constraint. If none exists, instantiate a new result
1872 object and return it. The object will not be saved into your storage
1873 until you call L<DBIx::Class::Row/insert> on it.
1875 You most likely want this method when looking for existing rows using
1876 a unique constraint that is not the primary key, or looking for
1879 If you want objects to be saved immediately, use L</find_or_create> instead.
1881 B<Note>: C<find_or_new> is probably not what you want when creating a
1882 new row in a table that uses primary keys supplied by the
1883 database. Passing in a primary key column with a value of I<undef>
1884 will cause L</find> to attempt to search for a row with a value of
1891 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1892 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1893 my $exists = $self->find($hash, $attrs);
1894 return defined $exists ? $exists : $self->new_result($hash);
1901 =item Arguments: \%vals
1903 =item Return Value: a L<DBIx::Class::Row> $object
1907 Attempt to create a single new row or a row with multiple related rows
1908 in the table represented by the resultset (and related tables). This
1909 will not check for duplicate rows before inserting, use
1910 L</find_or_create> to do that.
1912 To create one row for this resultset, pass a hashref of key/value
1913 pairs representing the columns of the table and the values you wish to
1914 store. If the appropriate relationships are set up, foreign key fields
1915 can also be passed an object representing the foreign row, and the
1916 value will be set to its primary key.
1918 To create related objects, pass a hashref for the value if the related
1919 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1920 and use the name of the relationship as the key. (NOT the name of the field,
1921 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1922 of hashrefs containing the data for each of the rows to create in the foreign
1923 tables, again using the relationship name as the key.
1925 Instead of hashrefs of plain related data (key/value pairs), you may
1926 also pass new or inserted objects. New objects (not inserted yet, see
1927 L</new>), will be inserted into their appropriate tables.
1929 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1931 Example of creating a new row.
1933 $person_rs->create({
1934 name=>"Some Person",
1935 email=>"somebody@someplace.com"
1938 Example of creating a new row and also creating rows in a related C<has_many>
1939 or C<has_one> resultset. Note Arrayref.
1942 { artistid => 4, name => 'Manufactured Crap', cds => [
1943 { title => 'My First CD', year => 2006 },
1944 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1949 Example of creating a new row and also creating a row in a related
1950 C<belongs_to>resultset. Note Hashref.
1953 title=>"Music for Silly Walks",
1956 name=>"Silly Musician",
1963 my ($self, $attrs) = @_;
1964 $self->throw_exception( "create needs a hashref" )
1965 unless ref $attrs eq 'HASH';
1966 return $self->new_result($attrs)->insert;
1969 =head2 find_or_create
1973 =item Arguments: \%vals, \%attrs?
1975 =item Return Value: $rowobject
1979 $cd->cd_to_producer->find_or_create({ producer => $producer },
1980 { key => 'primary });
1982 Tries to find a record based on its primary key or unique constraints; if none
1983 is found, creates one and returns that instead.
1985 my $cd = $schema->resultset('CD')->find_or_create({
1987 artist => 'Massive Attack',
1988 title => 'Mezzanine',
1992 Also takes an optional C<key> attribute, to search by a specific key or unique
1993 constraint. For example:
1995 my $cd = $schema->resultset('CD')->find_or_create(
1997 artist => 'Massive Attack',
1998 title => 'Mezzanine',
2000 { key => 'cd_artist_title' }
2003 B<Note>: Because find_or_create() reads from the database and then
2004 possibly inserts based on the result, this method is subject to a race
2005 condition. Another process could create a record in the table after
2006 the find has completed and before the create has started. To avoid
2007 this problem, use find_or_create() inside a transaction.
2009 B<Note>: C<find_or_create> is probably not what you want when creating
2010 a new row in a table that uses primary keys supplied by the
2011 database. Passing in a primary key column with a value of I<undef>
2012 will cause L</find> to attempt to search for a row with a value of
2015 See also L</find> and L</update_or_create>. For information on how to declare
2016 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2020 sub find_or_create {
2022 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2023 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2024 my $exists = $self->find($hash, $attrs);
2025 return defined $exists ? $exists : $self->create($hash);
2028 =head2 update_or_create
2032 =item Arguments: \%col_values, { key => $unique_constraint }?
2034 =item Return Value: $rowobject
2038 $resultset->update_or_create({ col => $val, ... });
2040 First, searches for an existing row matching one of the unique constraints
2041 (including the primary key) on the source of this resultset. If a row is
2042 found, updates it with the other given column values. Otherwise, creates a new
2045 Takes an optional C<key> attribute to search on a specific unique constraint.
2048 # In your application
2049 my $cd = $schema->resultset('CD')->update_or_create(
2051 artist => 'Massive Attack',
2052 title => 'Mezzanine',
2055 { key => 'cd_artist_title' }
2058 $cd->cd_to_producer->update_or_create({
2059 producer => $producer,
2066 If no C<key> is specified, it searches on all unique constraints defined on the
2067 source, including the primary key.
2069 If the C<key> is specified as C<primary>, it searches only on the primary key.
2071 See also L</find> and L</find_or_create>. For information on how to declare
2072 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2074 B<Note>: C<update_or_create> is probably not what you want when
2075 looking for a row in a table that uses primary keys supplied by the
2076 database, unless you actually have a key value. Passing in a primary
2077 key column with a value of I<undef> will cause L</find> to attempt to
2078 search for a row with a value of I<NULL>.
2082 sub update_or_create {
2084 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2085 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2087 my $row = $self->find($cond, $attrs);
2089 $row->update($cond);
2093 return $self->create($cond);
2096 =head2 update_or_new
2100 =item Arguments: \%col_values, { key => $unique_constraint }?
2102 =item Return Value: $rowobject
2106 $resultset->update_or_new({ col => $val, ... });
2108 First, searches for an existing row matching one of the unique constraints
2109 (including the primary key) on the source of this resultset. If a row is
2110 found, updates it with the other given column values. Otherwise, instantiate
2111 a new result object and return it. The object will not be saved into your storage
2112 until you call L<DBIx::Class::Row/insert> on it.
2114 Takes an optional C<key> attribute to search on a specific unique constraint.
2117 # In your application
2118 my $cd = $schema->resultset('CD')->update_or_new(
2120 artist => 'Massive Attack',
2121 title => 'Mezzanine',
2124 { key => 'cd_artist_title' }
2127 if ($cd->in_storage) {
2128 # the cd was updated
2131 # the cd is not yet in the database, let's insert it
2135 See also L</find>, L</find_or_create> and L<find_or_new>.
2141 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2142 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2144 my $row = $self->find( $cond, $attrs );
2145 if ( defined $row ) {
2146 $row->update($cond);
2150 return $self->new_result($cond);
2157 =item Arguments: none
2159 =item Return Value: \@cache_objects?
2163 Gets the contents of the cache for the resultset, if the cache is set.
2165 The cache is populated either by using the L</prefetch> attribute to
2166 L</search> or by calling L</set_cache>.
2178 =item Arguments: \@cache_objects
2180 =item Return Value: \@cache_objects
2184 Sets the contents of the cache for the resultset. Expects an arrayref
2185 of objects of the same class as those produced by the resultset. Note that
2186 if the cache is set the resultset will return the cached objects rather
2187 than re-querying the database even if the cache attr is not set.
2189 The contents of the cache can also be populated by using the
2190 L</prefetch> attribute to L</search>.
2195 my ( $self, $data ) = @_;
2196 $self->throw_exception("set_cache requires an arrayref")
2197 if defined($data) && (ref $data ne 'ARRAY');
2198 $self->{all_cache} = $data;
2205 =item Arguments: none
2207 =item Return Value: []
2211 Clears the cache for the resultset.
2216 shift->set_cache(undef);
2219 =head2 related_resultset
2223 =item Arguments: $relationship_name
2225 =item Return Value: $resultset
2229 Returns a related resultset for the supplied relationship name.
2231 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2235 sub related_resultset {
2236 my ($self, $rel) = @_;
2238 $self->{related_resultsets} ||= {};
2239 return $self->{related_resultsets}{$rel} ||= do {
2240 my $rel_obj = $self->result_source->relationship_info($rel);
2242 $self->throw_exception(
2243 "search_related: result source '" . $self->result_source->source_name .
2244 "' has no such relationship $rel")
2247 my ($from,$seen) = $self->_resolve_from($rel);
2249 my $join_count = $seen->{$rel};
2250 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2252 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2253 my %attrs = %{$self->{attrs}||{}};
2254 delete @attrs{qw(result_class alias)};
2258 if (my $cache = $self->get_cache) {
2259 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2260 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2265 my $rel_source = $self->result_source->related_source($rel);
2269 # The reason we do this now instead of passing the alias to the
2270 # search_rs below is that if you wrap/overload resultset on the
2271 # source you need to know what alias it's -going- to have for things
2272 # to work sanely (e.g. RestrictWithObject wants to be able to add
2273 # extra query restrictions, and these may need to be $alias.)
2275 my $attrs = $rel_source->resultset_attributes;
2276 local $attrs->{alias} = $alias;
2278 $rel_source->resultset
2286 where => $self->{cond},
2291 $new->set_cache($new_cache) if $new_cache;
2296 =head2 current_source_alias
2300 =item Arguments: none
2302 =item Return Value: $source_alias
2306 Returns the current table alias for the result source this resultset is built
2307 on, that will be used in the SQL query. Usually it is C<me>.
2309 Currently the source alias that refers to the result set returned by a
2310 L</search>/L</find> family method depends on how you got to the resultset: it's
2311 C<me> by default, but eg. L</search_related> aliases it to the related result
2312 source name (and keeps C<me> referring to the original result set). The long
2313 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2314 (and make this method unnecessary).
2316 Thus it's currently necessary to use this method in predefined queries (see
2317 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2318 source alias of the current result set:
2320 # in a result set class
2322 my ($self, $user) = @_;
2324 my $me = $self->current_source_alias;
2326 return $self->search(
2327 "$me.modified" => $user->id,
2333 sub current_source_alias {
2336 return ($self->{attrs} || {})->{alias} || 'me';
2339 # This code is called by search_related, and makes sure there
2340 # is clear separation between the joins before, during, and
2341 # after the relationship. This information is needed later
2342 # in order to properly resolve prefetch aliases (any alias
2343 # with a relation_chain_depth less than the depth of the
2344 # current prefetch is not considered)
2346 my ($self, $extra_join) = @_;
2347 my $source = $self->result_source;
2348 my $attrs = $self->{attrs};
2350 my $from = $attrs->{from}
2351 || [ { $attrs->{alias} => $source->from } ];
2353 my $seen = { %{$attrs->{seen_join}||{}} };
2355 # we need to take the prefetch the attrs into account before we
2356 # ->resolve_join as otherwise they get lost - captainL
2357 my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
2359 push @$from, $source->resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
2361 ++$seen->{-relation_chain_depth};
2363 push @$from, $source->resolve_join($extra_join, $attrs->{alias}, $seen);
2365 ++$seen->{-relation_chain_depth};
2367 return ($from,$seen);
2370 sub _resolved_attrs {
2372 return $self->{_attrs} if $self->{_attrs};
2374 my $attrs = { %{ $self->{attrs} || {} } };
2375 my $source = $self->result_source;
2376 my $alias = $attrs->{alias};
2378 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2381 # build columns (as long as select isn't set) into a set of as/select hashes
2382 unless ( $attrs->{select} ) {
2384 ( ref($_) eq 'HASH' )
2388 /^\Q${alias}.\E(.+)$/
2399 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2401 # add the additional columns on
2402 foreach ( 'include_columns', '+columns' ) {
2403 push @colbits, map {
2404 ( ref($_) eq 'HASH' )
2406 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2407 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2410 # start with initial select items
2411 if ( $attrs->{select} ) {
2413 ( ref $attrs->{select} eq 'ARRAY' )
2414 ? [ @{ $attrs->{select} } ]
2415 : [ $attrs->{select} ];
2419 ref $attrs->{as} eq 'ARRAY'
2420 ? [ @{ $attrs->{as} } ]
2423 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2428 # otherwise we intialise select & as to empty
2429 $attrs->{select} = [];
2433 # now add colbits to select/as
2434 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2435 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2438 if ( $adds = delete $attrs->{'+select'} ) {
2439 $adds = [$adds] unless ref $adds eq 'ARRAY';
2441 @{ $attrs->{select} },
2442 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2445 if ( $adds = delete $attrs->{'+as'} ) {
2446 $adds = [$adds] unless ref $adds eq 'ARRAY';
2447 push( @{ $attrs->{as} }, @$adds );
2450 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2452 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2453 my $join = delete $attrs->{join} || {};
2455 if ( defined $attrs->{prefetch} ) {
2456 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2460 $attrs->{from} = # have to copy here to avoid corrupting the original
2462 @{ $attrs->{from} },
2463 $source->resolve_join(
2464 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2470 $attrs->{group_by} ||= $attrs->{select}
2471 if delete $attrs->{distinct};
2472 if ( $attrs->{order_by} ) {
2473 $attrs->{order_by} = (
2474 ref( $attrs->{order_by} ) eq 'ARRAY'
2475 ? [ @{ $attrs->{order_by} } ]
2476 : [ $attrs->{order_by} ]
2480 $attrs->{order_by} = [];
2483 my $collapse = $attrs->{collapse} || {};
2484 if ( my $prefetch = delete $attrs->{prefetch} ) {
2485 $prefetch = $self->_merge_attr( {}, $prefetch );
2487 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2489 # bring joins back to level of current class
2490 my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
2492 $source->resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
2493 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2494 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2496 push( @{ $attrs->{order_by} }, @pre_order );
2498 $attrs->{collapse} = $collapse;
2500 if ( $attrs->{page} ) {
2501 $attrs->{offset} ||= 0;
2502 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2505 return $self->{_attrs} = $attrs;
2508 sub _joinpath_aliases {
2509 my ($self, $fromspec, $seen) = @_;
2512 return $paths unless ref $fromspec eq 'ARRAY';
2514 for my $j (@$fromspec) {
2516 next if ref $j ne 'ARRAY';
2517 next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
2520 $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
2521 push @{$p->{-join_aliases} }, $j->[0]{-join_alias};
2528 my ($self, $attr) = @_;
2530 if (ref $attr eq 'HASH') {
2531 return $self->_rollout_hash($attr);
2532 } elsif (ref $attr eq 'ARRAY') {
2533 return $self->_rollout_array($attr);
2539 sub _rollout_array {
2540 my ($self, $attr) = @_;
2543 foreach my $element (@{$attr}) {
2544 if (ref $element eq 'HASH') {
2545 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2546 } elsif (ref $element eq 'ARRAY') {
2547 # XXX - should probably recurse here
2548 push( @rolled_array, @{$self->_rollout_array($element)} );
2550 push( @rolled_array, $element );
2553 return \@rolled_array;
2557 my ($self, $attr) = @_;
2560 foreach my $key (keys %{$attr}) {
2561 push( @rolled_array, { $key => $attr->{$key} } );
2563 return \@rolled_array;
2566 sub _calculate_score {
2567 my ($self, $a, $b) = @_;
2569 if (ref $b eq 'HASH') {
2570 my ($b_key) = keys %{$b};
2571 if (ref $a eq 'HASH') {
2572 my ($a_key) = keys %{$a};
2573 if ($a_key eq $b_key) {
2574 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2579 return ($a eq $b_key) ? 1 : 0;
2582 if (ref $a eq 'HASH') {
2583 my ($a_key) = keys %{$a};
2584 return ($b eq $a_key) ? 1 : 0;
2586 return ($b eq $a) ? 1 : 0;
2592 my ($self, $orig, $import) = @_;
2594 return $import unless defined($orig);
2595 return $orig unless defined($import);
2597 $orig = $self->_rollout_attr($orig);
2598 $import = $self->_rollout_attr($import);
2601 foreach my $import_element ( @{$import} ) {
2602 # find best candidate from $orig to merge $b_element into
2603 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2604 foreach my $orig_element ( @{$orig} ) {
2605 my $score = $self->_calculate_score( $orig_element, $import_element );
2606 if ($score > $best_candidate->{score}) {
2607 $best_candidate->{position} = $position;
2608 $best_candidate->{score} = $score;
2612 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2614 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2615 push( @{$orig}, $import_element );
2617 my $orig_best = $orig->[$best_candidate->{position}];
2618 # merge orig_best and b_element together and replace original with merged
2619 if (ref $orig_best ne 'HASH') {
2620 $orig->[$best_candidate->{position}] = $import_element;
2621 } elsif (ref $import_element eq 'HASH') {
2622 my ($key) = keys %{$orig_best};
2623 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2626 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2636 $self->_source_handle($_[0]->handle);
2638 $self->_source_handle->resolve;
2642 =head2 throw_exception
2644 See L<DBIx::Class::Schema/throw_exception> for details.
2648 sub throw_exception {
2650 if (ref $self && $self->_source_handle->schema) {
2651 $self->_source_handle->schema->throw_exception(@_)
2658 # XXX: FIXME: Attributes docs need clearing up
2662 Attributes are used to refine a ResultSet in various ways when
2663 searching for data. They can be passed to any method which takes an
2664 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2667 These are in no particular order:
2673 =item Value: ( $order_by | \@order_by | \%order_by )
2677 Which column(s) to order the results by. If a single column name, or
2678 an arrayref of names is supplied, the argument is passed through
2679 directly to SQL. The hashref syntax allows for connection-agnostic
2680 specification of ordering direction:
2682 For descending order:
2684 order_by => { -desc => [qw/col1 col2 col3/] }
2686 For explicit ascending order:
2688 order_by => { -asc => 'col' }
2690 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2691 supported, although you are strongly encouraged to use the hashref
2692 syntax as outlined above.
2698 =item Value: \@columns
2702 Shortcut to request a particular set of columns to be retrieved. Each
2703 column spec may be a string (a table column name), or a hash (in which
2704 case the key is the C<as> value, and the value is used as the C<select>
2705 expression). Adds C<me.> onto the start of any column without a C<.> in
2706 it and sets C<select> from that, then auto-populates C<as> from
2707 C<select> as normal. (You may also use the C<cols> attribute, as in
2708 earlier versions of DBIC.)
2714 =item Value: \@columns
2718 Indicates additional columns to be selected from storage. Works the same
2719 as L</columns> but adds columns to the selection. (You may also use the
2720 C<include_columns> attribute, as in earlier versions of DBIC). For
2723 $schema->resultset('CD')->search(undef, {
2724 '+columns' => ['artist.name'],
2728 would return all CDs and include a 'name' column to the information
2729 passed to object inflation. Note that the 'artist' is the name of the
2730 column (or relationship) accessor, and 'name' is the name of the column
2731 accessor in the related table.
2733 =head2 include_columns
2737 =item Value: \@columns
2741 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2747 =item Value: \@select_columns
2751 Indicates which columns should be selected from the storage. You can use
2752 column names, or in the case of RDBMS back ends, function or stored procedure
2755 $rs = $schema->resultset('Employee')->search(undef, {
2758 { count => 'employeeid' },
2763 When you use function/stored procedure names and do not supply an C<as>
2764 attribute, the column names returned are storage-dependent. E.g. MySQL would
2765 return a column named C<count(employeeid)> in the above example.
2771 Indicates additional columns to be selected from storage. Works the same as
2772 L</select> but adds columns to the selection.
2780 Indicates additional column names for those added via L</+select>. See L</as>.
2788 =item Value: \@inflation_names
2792 Indicates column names for object inflation. That is, C<as>
2793 indicates the name that the column can be accessed as via the
2794 C<get_column> method (or via the object accessor, B<if one already
2795 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2797 The C<as> attribute is used in conjunction with C<select>,
2798 usually when C<select> contains one or more function or stored
2801 $rs = $schema->resultset('Employee')->search(undef, {
2804 { count => 'employeeid' }
2806 as => ['name', 'employee_count'],
2809 my $employee = $rs->first(); # get the first Employee
2811 If the object against which the search is performed already has an accessor
2812 matching a column name specified in C<as>, the value can be retrieved using
2813 the accessor as normal:
2815 my $name = $employee->name();
2817 If on the other hand an accessor does not exist in the object, you need to
2818 use C<get_column> instead:
2820 my $employee_count = $employee->get_column('employee_count');
2822 You can create your own accessors if required - see
2823 L<DBIx::Class::Manual::Cookbook> for details.
2825 Please note: This will NOT insert an C<AS employee_count> into the SQL
2826 statement produced, it is used for internal access only. Thus
2827 attempting to use the accessor in an C<order_by> clause or similar
2828 will fail miserably.
2830 To get around this limitation, you can supply literal SQL to your
2831 C<select> attibute that contains the C<AS alias> text, eg:
2833 select => [\'myfield AS alias']
2839 =item Value: ($rel_name | \@rel_names | \%rel_names)
2843 Contains a list of relationships that should be joined for this query. For
2846 # Get CDs by Nine Inch Nails
2847 my $rs = $schema->resultset('CD')->search(
2848 { 'artist.name' => 'Nine Inch Nails' },
2849 { join => 'artist' }
2852 Can also contain a hash reference to refer to the other relation's relations.
2855 package MyApp::Schema::Track;
2856 use base qw/DBIx::Class/;
2857 __PACKAGE__->table('track');
2858 __PACKAGE__->add_columns(qw/trackid cd position title/);
2859 __PACKAGE__->set_primary_key('trackid');
2860 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2863 # In your application
2864 my $rs = $schema->resultset('Artist')->search(
2865 { 'track.title' => 'Teardrop' },
2867 join => { cd => 'track' },
2868 order_by => 'artist.name',
2872 You need to use the relationship (not the table) name in conditions,
2873 because they are aliased as such. The current table is aliased as "me", so
2874 you need to use me.column_name in order to avoid ambiguity. For example:
2876 # Get CDs from 1984 with a 'Foo' track
2877 my $rs = $schema->resultset('CD')->search(
2880 'tracks.name' => 'Foo'
2882 { join => 'tracks' }
2885 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2886 similarly for a third time). For e.g.
2888 my $rs = $schema->resultset('Artist')->search({
2889 'cds.title' => 'Down to Earth',
2890 'cds_2.title' => 'Popular',
2892 join => [ qw/cds cds/ ],
2895 will return a set of all artists that have both a cd with title 'Down
2896 to Earth' and a cd with title 'Popular'.
2898 If you want to fetch related objects from other tables as well, see C<prefetch>
2901 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2907 =item Value: ($rel_name | \@rel_names | \%rel_names)
2911 Contains one or more relationships that should be fetched along with
2912 the main query (when they are accessed afterwards the data will
2913 already be available, without extra queries to the database). This is
2914 useful for when you know you will need the related objects, because it
2915 saves at least one query:
2917 my $rs = $schema->resultset('Tag')->search(
2926 The initial search results in SQL like the following:
2928 SELECT tag.*, cd.*, artist.* FROM tag
2929 JOIN cd ON tag.cd = cd.cdid
2930 JOIN artist ON cd.artist = artist.artistid
2932 L<DBIx::Class> has no need to go back to the database when we access the
2933 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2936 Simple prefetches will be joined automatically, so there is no need
2937 for a C<join> attribute in the above search.
2939 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2940 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2941 with an accessor type of 'single' or 'filter'). A more complex example that
2942 prefetches an artists cds, the tracks on those cds, and the tags associted
2943 with that artist is given below (assuming many-to-many from artists to tags):
2945 my $rs = $schema->resultset('Artist')->search(
2949 { cds => 'tracks' },
2950 { artist_tags => 'tags' }
2956 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2957 attributes will be ignored.
2967 Makes the resultset paged and specifies the page to retrieve. Effectively
2968 identical to creating a non-pages resultset and then calling ->page($page)
2971 If L<rows> attribute is not specified it defualts to 10 rows per page.
2973 When you have a paged resultset, L</count> will only return the number
2974 of rows in the page. To get the total, use the L</pager> and call
2975 C<total_entries> on it.
2985 Specifes the maximum number of rows for direct retrieval or the number of
2986 rows per page if the page attribute or method is used.
2992 =item Value: $offset
2996 Specifies the (zero-based) row number for the first row to be returned, or the
2997 of the first row of the first page if paging is used.
3003 =item Value: \@columns
3007 A arrayref of columns to group by. Can include columns of joined tables.
3009 group_by => [qw/ column1 column2 ... /]
3015 =item Value: $condition
3019 HAVING is a select statement attribute that is applied between GROUP BY and
3020 ORDER BY. It is applied to the after the grouping calculations have been
3023 having => { 'count(employee)' => { '>=', 100 } }
3029 =item Value: (0 | 1)
3033 Set to 1 to group by all columns.
3039 Adds to the WHERE clause.
3041 # only return rows WHERE deleted IS NULL for all searches
3042 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3044 Can be overridden by passing C<{ where => undef }> as an attribute
3051 Set to 1 to cache search results. This prevents extra SQL queries if you
3052 revisit rows in your ResultSet:
3054 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3056 while( my $artist = $resultset->next ) {
3060 $rs->first; # without cache, this would issue a query
3062 By default, searches are not cached.
3064 For more examples of using these attributes, see
3065 L<DBIx::Class::Manual::Cookbook>.
3071 =item Value: \@from_clause
3075 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3076 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3079 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3081 C<join> will usually do what you need and it is strongly recommended that you
3082 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3083 And we really do mean "cannot", not just tried and failed. Attempting to use
3084 this because you're having problems with C<join> is like trying to use x86
3085 ASM because you've got a syntax error in your C. Trust us on this.
3087 Now, if you're still really, really sure you need to use this (and if you're
3088 not 100% sure, ask the mailing list first), here's an explanation of how this
3091 The syntax is as follows -
3094 { <alias1> => <table1> },
3096 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3097 [], # nested JOIN (optional)
3098 { <table1.column1> => <table2.column2>, ... (more conditions) },
3100 # More of the above [ ] may follow for additional joins
3107 ON <table1.column1> = <table2.column2>
3108 <more joins may follow>
3110 An easy way to follow the examples below is to remember the following:
3112 Anything inside "[]" is a JOIN
3113 Anything inside "{}" is a condition for the enclosing JOIN
3115 The following examples utilize a "person" table in a family tree application.
3116 In order to express parent->child relationships, this table is self-joined:
3118 # Person->belongs_to('father' => 'Person');
3119 # Person->belongs_to('mother' => 'Person');
3121 C<from> can be used to nest joins. Here we return all children with a father,
3122 then search against all mothers of those children:
3124 $rs = $schema->resultset('Person')->search(
3127 alias => 'mother', # alias columns in accordance with "from"
3129 { mother => 'person' },
3132 { child => 'person' },
3134 { father => 'person' },
3135 { 'father.person_id' => 'child.father_id' }
3138 { 'mother.person_id' => 'child.mother_id' }
3145 # SELECT mother.* FROM person mother
3148 # JOIN person father
3149 # ON ( father.person_id = child.father_id )
3151 # ON ( mother.person_id = child.mother_id )
3153 The type of any join can be controlled manually. To search against only people
3154 with a father in the person table, we could explicitly use C<INNER JOIN>:
3156 $rs = $schema->resultset('Person')->search(
3159 alias => 'child', # alias columns in accordance with "from"
3161 { child => 'person' },
3163 { father => 'person', -join_type => 'inner' },
3164 { 'father.id' => 'child.father_id' }
3171 # SELECT child.* FROM person child
3172 # INNER JOIN person father ON child.father_id = father.id
3174 If you need to express really complex joins or you need a subselect, you
3175 can supply literal SQL to C<from> via a scalar reference. In this case
3176 the contents of the scalar will replace the table name asscoiated with the
3179 WARNING: This technique might very well not work as expected on chained
3180 searches - you have been warned.
3182 # Assuming the Event resultsource is defined as:
3184 MySchema::Event->add_columns (
3187 is_auto_increment => 1,
3196 MySchema::Event->set_primary_key ('sequence');
3198 # This will get back the latest event for every location. The column
3199 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3200 # combo to limit the resultset
3202 $rs = $schema->resultset('Event');
3203 $table = $rs->result_source->name;
3204 $latest = $rs->search (
3207 (SELECT e1.* FROM $table e1
3209 ON e1.location = e2.location
3210 AND e1.sequence < e2.sequence
3211 WHERE e2.sequence is NULL
3216 # Equivalent SQL (with the DBIC chunks added):
3218 SELECT me.sequence, me.location, me.type FROM
3219 (SELECT e1.* FROM events e1
3221 ON e1.location = e2.location
3222 AND e1.sequence < e2.sequence
3223 WHERE e2.sequence is NULL
3230 =item Value: ( 'update' | 'shared' )
3234 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT