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 # warn "ARRAY: " . Dumper $subquery;
800 $collapsed = $self->_collapse_query($subquery, $collapsed);
803 elsif (ref $query eq 'HASH') {
804 if (keys %$query and (keys %$query)[0] eq '-and') {
805 foreach my $subquery (@{$query->{-and}}) {
806 # warn "HASH: " . Dumper $subquery;
807 $collapsed = $self->_collapse_query($subquery, $collapsed);
811 # warn "LEAF: " . Dumper $query;
812 foreach my $col (keys %$query) {
813 my $value = $query->{$col};
814 $collapsed->{$col}{$value}++;
826 =item Arguments: $cond?
828 =item Return Value: $resultsetcolumn
832 my $max_length = $rs->get_column('length')->max;
834 Returns a L<DBIx::Class::ResultSetColumn> instance for a column of the ResultSet.
839 my ($self, $column) = @_;
840 my $new = DBIx::Class::ResultSetColumn->new($self, $column);
848 =item Arguments: $cond, \%attrs?
850 =item Return Value: $resultset (scalar context), @row_objs (list context)
854 # WHERE title LIKE '%blue%'
855 $cd_rs = $rs->search_like({ title => '%blue%'});
857 Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
858 that this is simply a convenience method retained for ex Class::DBI users.
859 You most likely want to use L</search> with specific operators.
861 For more information, see L<DBIx::Class::Manual::Cookbook>.
863 This method is deprecated and will be removed in 0.09. Use L</search()>
864 instead. An example conversion is:
866 ->search_like({ foo => 'bar' });
870 ->search({ foo => { like => 'bar' } });
877 'search_like() is deprecated and will be removed in 0.09.',
878 'Instead use ->search({ x => { -like => "y%" } })',
879 '(note the outer pair of {}s - they are important!)'
881 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
882 my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
883 $query->{$_} = { 'like' => $query->{$_} } for keys %$query;
884 return $class->search($query, { %$attrs });
891 =item Arguments: $first, $last
893 =item Return Value: $resultset (scalar context), @row_objs (list context)
897 Returns a resultset or object list representing a subset of elements from the
898 resultset slice is called on. Indexes are from 0, i.e., to get the first
901 my ($one, $two, $three) = $rs->slice(0, 2);
906 my ($self, $min, $max) = @_;
907 my $attrs = {}; # = { %{ $self->{attrs} || {} } };
908 $attrs->{offset} = $self->{attrs}{offset} || 0;
909 $attrs->{offset} += $min;
910 $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
911 return $self->search(undef(), $attrs);
912 #my $slice = (ref $self)->new($self->result_source, $attrs);
913 #return (wantarray ? $slice->all : $slice);
920 =item Arguments: none
922 =item Return Value: $result?
926 Returns the next element in the resultset (C<undef> is there is none).
928 Can be used to efficiently iterate over records in the resultset:
930 my $rs = $schema->resultset('CD')->search;
931 while (my $cd = $rs->next) {
935 Note that you need to store the resultset object, and call C<next> on it.
936 Calling C<< resultset('Table')->next >> repeatedly will always return the
937 first record from the resultset.
943 if (my $cache = $self->get_cache) {
944 $self->{all_cache_position} ||= 0;
945 return $cache->[$self->{all_cache_position}++];
947 if ($self->{attrs}{cache}) {
948 $self->{all_cache_position} = 1;
949 return ($self->all)[0];
951 if ($self->{stashed_objects}) {
952 my $obj = shift(@{$self->{stashed_objects}});
953 delete $self->{stashed_objects} unless @{$self->{stashed_objects}};
957 exists $self->{stashed_row}
958 ? @{delete $self->{stashed_row}}
959 : $self->cursor->next
961 return undef unless (@row);
962 my ($row, @more) = $self->_construct_object(@row);
963 $self->{stashed_objects} = \@more if @more;
967 sub _construct_object {
968 my ($self, @row) = @_;
969 my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
970 my @new = $self->result_class->inflate_result($self->result_source, @$info);
971 @new = $self->{_attrs}{record_filter}->(@new)
972 if exists $self->{_attrs}{record_filter};
976 sub _collapse_result {
977 my ($self, $as_proto, $row) = @_;
981 # 'foo' => [ undef, 'foo' ]
982 # 'foo.bar' => [ 'foo', 'bar' ]
983 # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
985 my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
987 my %collapse = %{$self->{_attrs}{collapse}||{}};
991 # if we're doing collapsing (has_many prefetch) we need to grab records
992 # until the PK changes, so fill @pri_index. if not, we leave it empty so
993 # we know we don't have to bother.
995 # the reason for not using the collapse stuff directly is because if you
996 # had for e.g. two artists in a row with no cds, the collapse info for
997 # both would be NULL (undef) so you'd lose the second artist
999 # store just the index so we can check the array positions from the row
1000 # without having to contruct the full hash
1002 if (keys %collapse) {
1003 my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
1004 foreach my $i (0 .. $#construct_as) {
1005 next if defined($construct_as[$i][0]); # only self table
1006 if (delete $pri{$construct_as[$i][1]}) {
1007 push(@pri_index, $i);
1009 last unless keys %pri; # short circuit (Johnny Five Is Alive!)
1013 # no need to do an if, it'll be empty if @pri_index is empty anyway
1015 my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
1019 do { # no need to check anything at the front, we always want the first row
1023 foreach my $this_as (@construct_as) {
1024 $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
1027 push(@const_rows, \%const);
1029 } until ( # no pri_index => no collapse => drop straight out
1032 do { # get another row, stash it, drop out if different PK
1034 @copy = $self->cursor->next;
1035 $self->{stashed_row} = \@copy;
1037 # last thing in do block, counts as true if anything doesn't match
1039 # check xor defined first for NULL vs. NOT NULL then if one is
1040 # defined the other must be so check string equality
1043 (defined $pri_vals{$_} ^ defined $copy[$_])
1044 || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
1049 my $alias = $self->{attrs}{alias};
1056 foreach my $const (@const_rows) {
1057 scalar @const_keys or do {
1058 @const_keys = sort { length($a) <=> length($b) } keys %$const;
1060 foreach my $key (@const_keys) {
1063 my @parts = split(/\./, $key);
1065 my $data = $const->{$key};
1066 foreach my $p (@parts) {
1067 $target = $target->[1]->{$p} ||= [];
1069 if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
1070 # collapsing at this point and on final part
1071 my $pos = $collapse_pos{$cur};
1072 CK: foreach my $ck (@ckey) {
1073 if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
1074 $collapse_pos{$cur} = $data;
1075 delete @collapse_pos{ # clear all positioning for sub-entries
1076 grep { m/^\Q${cur}.\E/ } keys %collapse_pos
1083 if (exists $collapse{$cur}) {
1084 $target = $target->[-1];
1087 $target->[0] = $data;
1089 $info->[0] = $const->{$key};
1097 =head2 result_source
1101 =item Arguments: $result_source?
1103 =item Return Value: $result_source
1107 An accessor for the primary ResultSource object from which this ResultSet
1114 =item Arguments: $result_class?
1116 =item Return Value: $result_class
1120 An accessor for the class to use when creating row objects. Defaults to
1121 C<< result_source->result_class >> - which in most cases is the name of the
1122 L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
1127 my ($self, $result_class) = @_;
1128 if ($result_class) {
1129 $self->ensure_class_loaded($result_class);
1130 $self->_result_class($result_class);
1132 $self->_result_class;
1139 =item Arguments: $cond, \%attrs??
1141 =item Return Value: $count
1145 Performs an SQL C<COUNT> with the same query as the resultset was built
1146 with to find the number of elements. If passed arguments, does a search
1147 on the resultset and counts the results of that.
1153 return $self->search(@_)->count if @_ and defined $_[0];
1154 return scalar @{ $self->get_cache } if $self->get_cache;
1155 my $count = $self->_count;
1156 return 0 unless $count;
1158 # need to take offset from resolved attrs
1160 $count -= $self->{_attrs}{offset} if $self->{_attrs}{offset};
1161 $count = $self->{attrs}{rows} if
1162 $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
1163 $count = 0 if ($count < 0);
1167 sub _count { # Separated out so pager can get the full count
1169 my $attrs = { %{$self->_resolved_attrs} };
1171 if (my $group_by = $attrs->{group_by}) {
1172 delete $attrs->{order_by};
1174 $attrs->{select} = $group_by;
1175 $attrs->{from} = [ { 'mesub' => (ref $self)->new($self->result_source, $attrs)->cursor->as_query } ];
1176 delete $attrs->{where};
1179 $attrs->{select} = { count => '*' };
1180 $attrs->{as} = [qw/count/];
1182 # offset, order by, group by, where and page are not needed to count. record_filter is cdbi
1183 delete $attrs->{$_} for qw/rows offset order_by group_by page pager record_filter/;
1185 my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
1186 my ($count) = $tmp_rs->cursor->next;
1194 =head2 count_literal
1198 =item Arguments: $sql_fragment, @bind_values
1200 =item Return Value: $count
1204 Counts the results in a literal query. Equivalent to calling L</search_literal>
1205 with the passed arguments, then L</count>.
1209 sub count_literal { shift->search_literal(@_)->count; }
1215 =item Arguments: none
1217 =item Return Value: @objects
1221 Returns all elements in the resultset. Called implicitly if the resultset
1222 is returned in list context.
1229 $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
1232 return @{ $self->get_cache } if $self->get_cache;
1236 # TODO: don't call resolve here
1237 if (keys %{$self->_resolved_attrs->{collapse}}) {
1238 # if ($self->{attrs}{prefetch}) {
1239 # Using $self->cursor->all is really just an optimisation.
1240 # If we're collapsing has_many prefetches it probably makes
1241 # very little difference, and this is cleaner than hacking
1242 # _construct_object to survive the approach
1243 my @row = $self->cursor->next;
1245 push(@obj, $self->_construct_object(@row));
1246 @row = (exists $self->{stashed_row}
1247 ? @{delete $self->{stashed_row}}
1248 : $self->cursor->next);
1251 @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
1254 $self->set_cache(\@obj) if $self->{attrs}{cache};
1262 =item Arguments: none
1264 =item Return Value: $self
1268 Resets the resultset's cursor, so you can iterate through the elements again.
1274 delete $self->{_attrs} if exists $self->{_attrs};
1275 $self->{all_cache_position} = 0;
1276 $self->cursor->reset;
1284 =item Arguments: none
1286 =item Return Value: $object?
1290 Resets the resultset and returns an object for the first result (if the
1291 resultset returns anything).
1296 return $_[0]->reset->next;
1299 # _cond_for_update_delete
1301 # update/delete require the condition to be modified to handle
1302 # the differing SQL syntax available. This transforms the $self->{cond}
1303 # appropriately, returning the new condition.
1305 sub _cond_for_update_delete {
1306 my ($self, $full_cond) = @_;
1309 $full_cond ||= $self->{cond};
1310 # No-op. No condition, we're updating/deleting everything
1311 return $cond unless ref $full_cond;
1313 if (ref $full_cond eq 'ARRAY') {
1317 foreach my $key (keys %{$_}) {
1319 $hash{$1} = $_->{$key};
1325 elsif (ref $full_cond eq 'HASH') {
1326 if ((keys %{$full_cond})[0] eq '-and') {
1329 my @cond = @{$full_cond->{-and}};
1330 for (my $i = 0; $i < @cond; $i++) {
1331 my $entry = $cond[$i];
1334 if (ref $entry eq 'HASH') {
1335 $hash = $self->_cond_for_update_delete($entry);
1338 $entry =~ /([^.]+)$/;
1339 $hash->{$1} = $cond[++$i];
1342 push @{$cond->{-and}}, $hash;
1346 foreach my $key (keys %{$full_cond}) {
1348 $cond->{$1} = $full_cond->{$key};
1353 $self->throw_exception(
1354 "Can't update/delete on resultset with condition unless hash or array"
1366 =item Arguments: \%values
1368 =item Return Value: $storage_rv
1372 Sets the specified columns in the resultset to the supplied values in a
1373 single query. Return value will be true if the update succeeded or false
1374 if no records were updated; exact type of success value is storage-dependent.
1379 my ($self, $values) = @_;
1380 $self->throw_exception("Values for update must be a hash")
1381 unless ref $values eq 'HASH';
1383 carp( 'WARNING! Currently $rs->update() does not generate proper SQL'
1384 . ' on joined resultsets, and may affect rows well outside of the'
1385 . ' contents of $rs. Use at your own risk' )
1386 if ( $self->{attrs}{seen_join} );
1388 my $cond = $self->_cond_for_update_delete;
1390 return $self->result_source->storage->update(
1391 $self->result_source, $values, $cond
1399 =item Arguments: \%values
1401 =item Return Value: 1
1405 Fetches all objects and updates them one at a time. Note that C<update_all>
1406 will run DBIC cascade triggers, while L</update> will not.
1411 my ($self, $values) = @_;
1412 $self->throw_exception("Values for update must be a hash")
1413 unless ref $values eq 'HASH';
1414 foreach my $obj ($self->all) {
1415 $obj->set_columns($values)->update;
1424 =item Arguments: none
1426 =item Return Value: 1
1430 Deletes the contents of the resultset from its result source. Note that this
1431 will not run DBIC cascade triggers. See L</delete_all> if you need triggers
1432 to run. See also L<DBIx::Class::Row/delete>.
1434 delete may not generate correct SQL for a query with joins or a resultset
1435 chained from a related resultset. In this case it will generate a warning:-
1437 WARNING! Currently $rs->delete() does not generate proper SQL on
1438 joined resultsets, and may delete rows well outside of the contents
1439 of $rs. Use at your own risk
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")
1450 carp( 'WARNING! Currently $rs->delete() does not generate proper SQL'
1451 . ' on joined resultsets, and may delete rows well outside of the'
1452 . ' contents of $rs. Use at your own risk' )
1453 if ( $self->{attrs}{seen_join} );
1454 my $cond = $self->_cond_for_update_delete;
1456 $self->result_source->storage->delete($self->result_source, $cond);
1464 =item Arguments: none
1466 =item Return Value: 1
1470 Fetches all objects and deletes them one at a time. Note that C<delete_all>
1471 will run DBIC cascade triggers, while L</delete> will not.
1477 $_->delete for $self->all;
1485 =item Arguments: \@data;
1489 Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
1490 For the arrayref of hashrefs style each hashref should be a structure suitable
1491 forsubmitting to a $resultset->create(...) method.
1493 In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
1494 to insert the data, as this is a faster method.
1496 Otherwise, each set of data is inserted into the database using
1497 L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
1498 objects is returned.
1500 Example: Assuming an Artist Class that has many CDs Classes relating:
1502 my $Artist_rs = $schema->resultset("Artist");
1504 ## Void Context Example
1505 $Artist_rs->populate([
1506 { artistid => 4, name => 'Manufactured Crap', cds => [
1507 { title => 'My First CD', year => 2006 },
1508 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1511 { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
1512 { title => 'My parents sold me to a record company' ,year => 2005 },
1513 { title => 'Why Am I So Ugly?', year => 2006 },
1514 { title => 'I Got Surgery and am now Popular', year => 2007 }
1519 ## Array Context Example
1520 my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
1521 { name => "Artist One"},
1522 { name => "Artist Two"},
1523 { name => "Artist Three", cds=> [
1524 { title => "First CD", year => 2007},
1525 { title => "Second CD", year => 2008},
1529 print $ArtistOne->name; ## response is 'Artist One'
1530 print $ArtistThree->cds->count ## reponse is '2'
1532 For the arrayref of arrayrefs style, the first element should be a list of the
1533 fieldsnames to which the remaining elements are rows being inserted. For
1536 $Arstist_rs->populate([
1537 [qw/artistid name/],
1538 [100, 'A Formally Unknown Singer'],
1539 [101, 'A singer that jumped the shark two albums ago'],
1540 [102, 'An actually cool singer.'],
1543 Please note an important effect on your data when choosing between void and
1544 wantarray context. Since void context goes straight to C<insert_bulk> in
1545 L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
1546 c<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
1547 create primary keys for you, you will find that your PKs are empty. In this
1548 case you will have to use the wantarray context in order to create those
1554 my $self = shift @_;
1555 my $data = ref $_[0][0] eq 'HASH'
1556 ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
1557 $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
1559 if(defined wantarray) {
1561 foreach my $item (@$data) {
1562 push(@created, $self->create($item));
1566 my ($first, @rest) = @$data;
1568 my @names = grep {!ref $first->{$_}} keys %$first;
1569 my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
1570 my @pks = $self->result_source->primary_columns;
1572 ## do the belongs_to relationships
1573 foreach my $index (0..$#$data) {
1574 if( grep { !defined $data->[$index]->{$_} } @pks ) {
1575 my @ret = $self->populate($data);
1579 foreach my $rel (@rels) {
1580 next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
1581 my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
1582 my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
1583 my $related = $result->result_source->resolve_condition(
1584 $result->result_source->relationship_info($reverse)->{cond},
1589 delete $data->[$index]->{$rel};
1590 $data->[$index] = {%{$data->[$index]}, %$related};
1592 push @names, keys %$related if $index == 0;
1596 ## do bulk insert on current row
1597 my @values = map { [ @$_{@names} ] } @$data;
1599 $self->result_source->storage->insert_bulk(
1600 $self->result_source,
1605 ## do the has_many relationships
1606 foreach my $item (@$data) {
1608 foreach my $rel (@rels) {
1609 next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
1611 my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
1612 || $self->throw_exception('Cannot find the relating object.');
1614 my $child = $parent->$rel;
1616 my $related = $child->result_source->resolve_condition(
1617 $parent->result_source->relationship_info($rel)->{cond},
1622 my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
1623 my @populate = map { {%$_, %$related} } @rows_to_add;
1625 $child->populate( \@populate );
1631 =head2 _normalize_populate_args ($args)
1633 Private method used by L</populate> to normalize its incoming arguments. Factored
1634 out in case you want to subclass and accept new argument structures to the
1635 L</populate> method.
1639 sub _normalize_populate_args {
1640 my ($self, $data) = @_;
1641 my @names = @{shift(@$data)};
1642 my @results_to_create;
1643 foreach my $datum (@$data) {
1644 my %result_to_create;
1645 foreach my $index (0..$#names) {
1646 $result_to_create{$names[$index]} = $$datum[$index];
1648 push @results_to_create, \%result_to_create;
1650 return \@results_to_create;
1657 =item Arguments: none
1659 =item Return Value: $pager
1663 Return Value a L<Data::Page> object for the current resultset. Only makes
1664 sense for queries with a C<page> attribute.
1666 To get the full count of entries for a paged resultset, call
1667 C<total_entries> on the L<Data::Page> object.
1673 my $attrs = $self->{attrs};
1674 $self->throw_exception("Can't create pager for non-paged rs")
1675 unless $self->{attrs}{page};
1676 $attrs->{rows} ||= 10;
1677 return $self->{pager} ||= Data::Page->new(
1678 $self->_count, $attrs->{rows}, $self->{attrs}{page});
1685 =item Arguments: $page_number
1687 =item Return Value: $rs
1691 Returns a resultset for the $page_number page of the resultset on which page
1692 is called, where each page contains a number of rows equal to the 'rows'
1693 attribute set on the resultset (10 by default).
1698 my ($self, $page) = @_;
1699 return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
1706 =item Arguments: \%vals
1708 =item Return Value: $rowobject
1712 Creates a new row object in the resultset's result class and returns
1713 it. The row is not inserted into the database at this point, call
1714 L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
1715 will tell you whether the row object has been inserted or not.
1717 Passes the hashref of input on to L<DBIx::Class::Row/new>.
1722 my ($self, $values) = @_;
1723 $self->throw_exception( "new_result needs a hash" )
1724 unless (ref $values eq 'HASH');
1727 my $alias = $self->{attrs}{alias};
1730 defined $self->{cond}
1731 && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
1733 %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
1734 $new{-from_resultset} = [ keys %new ] if keys %new;
1736 $self->throw_exception(
1737 "Can't abstract implicit construct, condition not a hash"
1738 ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
1740 my $collapsed_cond = (
1742 ? $self->_collapse_cond($self->{cond})
1746 # precendence must be given to passed values over values inherited from
1747 # the cond, so the order here is important.
1748 my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
1749 while( my($col,$value) = each %implied ){
1750 if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
1751 $new{$col} = $value->{'='};
1754 $new{$col} = $value if $self->_is_deterministic_value($value);
1760 %{ $self->_remove_alias($values, $alias) },
1761 -source_handle => $self->_source_handle,
1762 -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
1765 return $self->result_class->new(\%new);
1768 # _is_deterministic_value
1770 # Make an effor to strip non-deterministic values from the condition,
1771 # to make sure new_result chokes less
1773 sub _is_deterministic_value {
1776 my $ref_type = ref $value;
1777 return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
1778 return 1 if Scalar::Util::blessed($value);
1784 # Recursively collapse the condition.
1786 sub _collapse_cond {
1787 my ($self, $cond, $collapsed) = @_;
1791 if (ref $cond eq 'ARRAY') {
1792 foreach my $subcond (@$cond) {
1793 next unless ref $subcond; # -or
1794 # warn "ARRAY: " . Dumper $subcond;
1795 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1798 elsif (ref $cond eq 'HASH') {
1799 if (keys %$cond and (keys %$cond)[0] eq '-and') {
1800 foreach my $subcond (@{$cond->{-and}}) {
1801 # warn "HASH: " . Dumper $subcond;
1802 $collapsed = $self->_collapse_cond($subcond, $collapsed);
1806 # warn "LEAF: " . Dumper $cond;
1807 foreach my $col (keys %$cond) {
1808 my $value = $cond->{$col};
1809 $collapsed->{$col} = $value;
1819 # Remove the specified alias from the specified query hash. A copy is made so
1820 # the original query is not modified.
1823 my ($self, $query, $alias) = @_;
1825 my %orig = %{ $query || {} };
1828 foreach my $key (keys %orig) {
1830 $unaliased{$key} = $orig{$key};
1833 $unaliased{$1} = $orig{$key}
1834 if $key =~ m/^(?:\Q$alias\E\.)?([^.]+)$/;
1840 =head2 as_query (EXPERIMENTAL)
1844 =item Arguments: none
1846 =item Return Value: \[ $sql, @bind ]
1850 Returns the SQL query and bind vars associated with the invocant.
1852 This is generally used as the RHS for a subquery.
1854 B<NOTE>: This feature is still experimental.
1858 sub as_query { return shift->cursor->as_query(@_) }
1864 =item Arguments: \%vals, \%attrs?
1866 =item Return Value: $rowobject
1870 my $artist = $schema->resultset('Artist')->find_or_new(
1871 { artist => 'fred' }, { key => 'artists' });
1873 $cd->cd_to_producer->find_or_new({ producer => $producer },
1874 { key => 'primary });
1876 Find an existing record from this resultset, based on its primary
1877 key, or a unique constraint. If none exists, instantiate a new result
1878 object and return it. The object will not be saved into your storage
1879 until you call L<DBIx::Class::Row/insert> on it.
1881 You most likely want this method when looking for existing rows using
1882 a unique constraint that is not the primary key, or looking for
1885 If you want objects to be saved immediately, use L</find_or_create> instead.
1887 B<Note>: C<find_or_new> is probably not what you want when creating a
1888 new row in a table that uses primary keys supplied by the
1889 database. Passing in a primary key column with a value of I<undef>
1890 will cause L</find> to attempt to search for a row with a value of
1897 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
1898 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
1899 my $exists = $self->find($hash, $attrs);
1900 return defined $exists ? $exists : $self->new_result($hash);
1907 =item Arguments: \%vals
1909 =item Return Value: a L<DBIx::Class::Row> $object
1913 Attempt to create a single new row or a row with multiple related rows
1914 in the table represented by the resultset (and related tables). This
1915 will not check for duplicate rows before inserting, use
1916 L</find_or_create> to do that.
1918 To create one row for this resultset, pass a hashref of key/value
1919 pairs representing the columns of the table and the values you wish to
1920 store. If the appropriate relationships are set up, foreign key fields
1921 can also be passed an object representing the foreign row, and the
1922 value will be set to its primary key.
1924 To create related objects, pass a hashref for the value if the related
1925 item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
1926 and use the name of the relationship as the key. (NOT the name of the field,
1927 necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
1928 of hashrefs containing the data for each of the rows to create in the foreign
1929 tables, again using the relationship name as the key.
1931 Instead of hashrefs of plain related data (key/value pairs), you may
1932 also pass new or inserted objects. New objects (not inserted yet, see
1933 L</new>), will be inserted into their appropriate tables.
1935 Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
1937 Example of creating a new row.
1939 $person_rs->create({
1940 name=>"Some Person",
1941 email=>"somebody@someplace.com"
1944 Example of creating a new row and also creating rows in a related C<has_many>
1945 or C<has_one> resultset. Note Arrayref.
1948 { artistid => 4, name => 'Manufactured Crap', cds => [
1949 { title => 'My First CD', year => 2006 },
1950 { title => 'Yet More Tweeny-Pop crap', year => 2007 },
1955 Example of creating a new row and also creating a row in a related
1956 C<belongs_to>resultset. Note Hashref.
1959 title=>"Music for Silly Walks",
1962 name=>"Silly Musician",
1969 my ($self, $attrs) = @_;
1970 $self->throw_exception( "create needs a hashref" )
1971 unless ref $attrs eq 'HASH';
1972 return $self->new_result($attrs)->insert;
1975 =head2 find_or_create
1979 =item Arguments: \%vals, \%attrs?
1981 =item Return Value: $rowobject
1985 $cd->cd_to_producer->find_or_create({ producer => $producer },
1986 { key => 'primary });
1988 Tries to find a record based on its primary key or unique constraints; if none
1989 is found, creates one and returns that instead.
1991 my $cd = $schema->resultset('CD')->find_or_create({
1993 artist => 'Massive Attack',
1994 title => 'Mezzanine',
1998 Also takes an optional C<key> attribute, to search by a specific key or unique
1999 constraint. For example:
2001 my $cd = $schema->resultset('CD')->find_or_create(
2003 artist => 'Massive Attack',
2004 title => 'Mezzanine',
2006 { key => 'cd_artist_title' }
2009 B<Note>: Because find_or_create() reads from the database and then
2010 possibly inserts based on the result, this method is subject to a race
2011 condition. Another process could create a record in the table after
2012 the find has completed and before the create has started. To avoid
2013 this problem, use find_or_create() inside a transaction.
2015 B<Note>: C<find_or_create> is probably not what you want when creating
2016 a new row in a table that uses primary keys supplied by the
2017 database. Passing in a primary key column with a value of I<undef>
2018 will cause L</find> to attempt to search for a row with a value of
2021 See also L</find> and L</update_or_create>. For information on how to declare
2022 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2026 sub find_or_create {
2028 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2029 my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
2030 my $exists = $self->find($hash, $attrs);
2031 return defined $exists ? $exists : $self->create($hash);
2034 =head2 update_or_create
2038 =item Arguments: \%col_values, { key => $unique_constraint }?
2040 =item Return Value: $rowobject
2044 $resultset->update_or_create({ col => $val, ... });
2046 First, searches for an existing row matching one of the unique constraints
2047 (including the primary key) on the source of this resultset. If a row is
2048 found, updates it with the other given column values. Otherwise, creates a new
2051 Takes an optional C<key> attribute to search on a specific unique constraint.
2054 # In your application
2055 my $cd = $schema->resultset('CD')->update_or_create(
2057 artist => 'Massive Attack',
2058 title => 'Mezzanine',
2061 { key => 'cd_artist_title' }
2064 $cd->cd_to_producer->update_or_create({
2065 producer => $producer,
2072 If no C<key> is specified, it searches on all unique constraints defined on the
2073 source, including the primary key.
2075 If the C<key> is specified as C<primary>, it searches only on the primary key.
2077 See also L</find> and L</find_or_create>. For information on how to declare
2078 unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
2080 B<Note>: C<update_or_create> is probably not what you want when
2081 looking for a row in a table that uses primary keys supplied by the
2082 database, unless you actually have a key value. Passing in a primary
2083 key column with a value of I<undef> will cause L</find> to attempt to
2084 search for a row with a value of I<NULL>.
2088 sub update_or_create {
2090 my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
2091 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2093 my $row = $self->find($cond, $attrs);
2095 $row->update($cond);
2099 return $self->create($cond);
2102 =head2 update_or_new
2106 =item Arguments: \%col_values, { key => $unique_constraint }?
2108 =item Return Value: $rowobject
2112 $resultset->update_or_new({ col => $val, ... });
2114 First, searches for an existing row matching one of the unique constraints
2115 (including the primary key) on the source of this resultset. If a row is
2116 found, updates it with the other given column values. Otherwise, instantiate
2117 a new result object and return it. The object will not be saved into your storage
2118 until you call L<DBIx::Class::Row/insert> on it.
2120 Takes an optional C<key> attribute to search on a specific unique constraint.
2123 # In your application
2124 my $cd = $schema->resultset('CD')->update_or_new(
2126 artist => 'Massive Attack',
2127 title => 'Mezzanine',
2130 { key => 'cd_artist_title' }
2133 if ($cd->in_storage) {
2134 # the cd was updated
2137 # the cd is not yet in the database, let's insert it
2141 See also L</find>, L</find_or_create> and L<find_or_new>.
2147 my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
2148 my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
2150 my $row = $self->find( $cond, $attrs );
2151 if ( defined $row ) {
2152 $row->update($cond);
2156 return $self->new_result($cond);
2163 =item Arguments: none
2165 =item Return Value: \@cache_objects?
2169 Gets the contents of the cache for the resultset, if the cache is set.
2171 The cache is populated either by using the L</prefetch> attribute to
2172 L</search> or by calling L</set_cache>.
2184 =item Arguments: \@cache_objects
2186 =item Return Value: \@cache_objects
2190 Sets the contents of the cache for the resultset. Expects an arrayref
2191 of objects of the same class as those produced by the resultset. Note that
2192 if the cache is set the resultset will return the cached objects rather
2193 than re-querying the database even if the cache attr is not set.
2195 The contents of the cache can also be populated by using the
2196 L</prefetch> attribute to L</search>.
2201 my ( $self, $data ) = @_;
2202 $self->throw_exception("set_cache requires an arrayref")
2203 if defined($data) && (ref $data ne 'ARRAY');
2204 $self->{all_cache} = $data;
2211 =item Arguments: none
2213 =item Return Value: []
2217 Clears the cache for the resultset.
2222 shift->set_cache(undef);
2225 =head2 related_resultset
2229 =item Arguments: $relationship_name
2231 =item Return Value: $resultset
2235 Returns a related resultset for the supplied relationship name.
2237 $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
2241 sub related_resultset {
2242 my ($self, $rel) = @_;
2244 $self->{related_resultsets} ||= {};
2245 return $self->{related_resultsets}{$rel} ||= do {
2246 my $rel_obj = $self->result_source->relationship_info($rel);
2248 $self->throw_exception(
2249 "search_related: result source '" . $self->result_source->source_name .
2250 "' has no such relationship $rel")
2253 my ($from,$seen) = $self->_resolve_from($rel);
2255 my $join_count = $seen->{$rel};
2256 my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
2258 #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
2259 my %attrs = %{$self->{attrs}||{}};
2260 delete @attrs{qw(result_class alias)};
2264 if (my $cache = $self->get_cache) {
2265 if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
2266 $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
2271 my $rel_source = $self->result_source->related_source($rel);
2275 # The reason we do this now instead of passing the alias to the
2276 # search_rs below is that if you wrap/overload resultset on the
2277 # source you need to know what alias it's -going- to have for things
2278 # to work sanely (e.g. RestrictWithObject wants to be able to add
2279 # extra query restrictions, and these may need to be $alias.)
2281 my $attrs = $rel_source->resultset_attributes;
2282 local $attrs->{alias} = $alias;
2284 $rel_source->resultset
2292 where => $self->{cond},
2297 $new->set_cache($new_cache) if $new_cache;
2302 =head2 current_source_alias
2306 =item Arguments: none
2308 =item Return Value: $source_alias
2312 Returns the current table alias for the result source this resultset is built
2313 on, that will be used in the SQL query. Usually it is C<me>.
2315 Currently the source alias that refers to the result set returned by a
2316 L</search>/L</find> family method depends on how you got to the resultset: it's
2317 C<me> by default, but eg. L</search_related> aliases it to the related result
2318 source name (and keeps C<me> referring to the original result set). The long
2319 term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
2320 (and make this method unnecessary).
2322 Thus it's currently necessary to use this method in predefined queries (see
2323 L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
2324 source alias of the current result set:
2326 # in a result set class
2328 my ($self, $user) = @_;
2330 my $me = $self->current_source_alias;
2332 return $self->search(
2333 "$me.modified" => $user->id,
2339 sub current_source_alias {
2342 return ($self->{attrs} || {})->{alias} || 'me';
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 my $join = ($attrs->{join}
2356 ? [ $attrs->{join}, $extra_join ]
2359 # we need to take the prefetch the attrs into account before we
2360 # ->resolve_join as otherwise they get lost - captainL
2361 my $merged = $self->_merge_attr( $join, $attrs->{prefetch} );
2365 ($join ? $source->resolve_join($merged, $attrs->{alias}, $seen) : ()),
2368 return ($from,$seen);
2371 sub _resolved_attrs {
2373 return $self->{_attrs} if $self->{_attrs};
2375 my $attrs = { %{ $self->{attrs} || {} } };
2376 my $source = $self->result_source;
2377 my $alias = $attrs->{alias};
2379 $attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
2382 # build columns (as long as select isn't set) into a set of as/select hashes
2383 unless ( $attrs->{select} ) {
2385 ( ref($_) eq 'HASH' ) ? $_
2388 /^\Q${alias}.\E(.+)$/ ? $1
2390 ) => ( /\./ ? $_ : "${alias}.$_" )
2392 } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
2394 # add the additional columns on
2395 foreach ( 'include_columns', '+columns' ) {
2396 push @colbits, map {
2397 ( ref($_) eq 'HASH' )
2399 : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
2400 } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
2403 # start with initial select items
2404 if ( $attrs->{select} ) {
2406 ( ref $attrs->{select} eq 'ARRAY' )
2407 ? [ @{ $attrs->{select} } ]
2408 : [ $attrs->{select} ];
2412 ref $attrs->{as} eq 'ARRAY'
2413 ? [ @{ $attrs->{as} } ]
2416 : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
2421 # otherwise we intialise select & as to empty
2422 $attrs->{select} = [];
2426 # now add colbits to select/as
2427 push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
2428 push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
2431 if ( $adds = delete $attrs->{'+select'} ) {
2432 $adds = [$adds] unless ref $adds eq 'ARRAY';
2434 @{ $attrs->{select} },
2435 map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
2438 if ( $adds = delete $attrs->{'+as'} ) {
2439 $adds = [$adds] unless ref $adds eq 'ARRAY';
2440 push( @{ $attrs->{as} }, @$adds );
2443 $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
2445 if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
2446 my $join = delete $attrs->{join} || {};
2448 if ( defined $attrs->{prefetch} ) {
2449 $join = $self->_merge_attr( $join, $attrs->{prefetch} );
2453 $attrs->{from} = # have to copy here to avoid corrupting the original
2455 @{ $attrs->{from} },
2456 $source->resolve_join(
2457 $join, $alias, { %{ $attrs->{seen_join} || {} } }
2463 $attrs->{group_by} ||= $attrs->{select}
2464 if delete $attrs->{distinct};
2465 if ( $attrs->{order_by} ) {
2466 $attrs->{order_by} = (
2467 ref( $attrs->{order_by} ) eq 'ARRAY'
2468 ? [ @{ $attrs->{order_by} } ]
2469 : [ $attrs->{order_by} ]
2473 $attrs->{order_by} = [];
2476 my $collapse = $attrs->{collapse} || {};
2477 if ( my $prefetch = delete $attrs->{prefetch} ) {
2478 $prefetch = $self->_merge_attr( {}, $prefetch );
2480 my $seen = { %{ $attrs->{seen_join} || {} } };
2481 foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
2483 # bring joins back to level of current class
2485 $source->resolve_prefetch( $p, $alias, $seen, \@pre_order, $collapse );
2486 push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
2487 push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
2489 push( @{ $attrs->{order_by} }, @pre_order );
2491 $attrs->{collapse} = $collapse;
2493 if ( $attrs->{page} ) {
2494 $attrs->{offset} ||= 0;
2495 $attrs->{offset} += ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
2498 return $self->{_attrs} = $attrs;
2502 my ($self, $attr) = @_;
2504 if (ref $attr eq 'HASH') {
2505 return $self->_rollout_hash($attr);
2506 } elsif (ref $attr eq 'ARRAY') {
2507 return $self->_rollout_array($attr);
2513 sub _rollout_array {
2514 my ($self, $attr) = @_;
2517 foreach my $element (@{$attr}) {
2518 if (ref $element eq 'HASH') {
2519 push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
2520 } elsif (ref $element eq 'ARRAY') {
2521 # XXX - should probably recurse here
2522 push( @rolled_array, @{$self->_rollout_array($element)} );
2524 push( @rolled_array, $element );
2527 return \@rolled_array;
2531 my ($self, $attr) = @_;
2534 foreach my $key (keys %{$attr}) {
2535 push( @rolled_array, { $key => $attr->{$key} } );
2537 return \@rolled_array;
2540 sub _calculate_score {
2541 my ($self, $a, $b) = @_;
2543 if (ref $b eq 'HASH') {
2544 my ($b_key) = keys %{$b};
2545 if (ref $a eq 'HASH') {
2546 my ($a_key) = keys %{$a};
2547 if ($a_key eq $b_key) {
2548 return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
2553 return ($a eq $b_key) ? 1 : 0;
2556 if (ref $a eq 'HASH') {
2557 my ($a_key) = keys %{$a};
2558 return ($b eq $a_key) ? 1 : 0;
2560 return ($b eq $a) ? 1 : 0;
2566 my ($self, $orig, $import) = @_;
2568 return $import unless defined($orig);
2569 return $orig unless defined($import);
2571 $orig = $self->_rollout_attr($orig);
2572 $import = $self->_rollout_attr($import);
2575 foreach my $import_element ( @{$import} ) {
2576 # find best candidate from $orig to merge $b_element into
2577 my $best_candidate = { position => undef, score => 0 }; my $position = 0;
2578 foreach my $orig_element ( @{$orig} ) {
2579 my $score = $self->_calculate_score( $orig_element, $import_element );
2580 if ($score > $best_candidate->{score}) {
2581 $best_candidate->{position} = $position;
2582 $best_candidate->{score} = $score;
2586 my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
2588 if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
2589 push( @{$orig}, $import_element );
2591 my $orig_best = $orig->[$best_candidate->{position}];
2592 # merge orig_best and b_element together and replace original with merged
2593 if (ref $orig_best ne 'HASH') {
2594 $orig->[$best_candidate->{position}] = $import_element;
2595 } elsif (ref $import_element eq 'HASH') {
2596 my ($key) = keys %{$orig_best};
2597 $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
2600 $seen_keys->{$import_key} = 1; # don't merge the same key twice
2610 $self->_source_handle($_[0]->handle);
2612 $self->_source_handle->resolve;
2616 =head2 throw_exception
2618 See L<DBIx::Class::Schema/throw_exception> for details.
2622 sub throw_exception {
2624 if (ref $self && $self->_source_handle->schema) {
2625 $self->_source_handle->schema->throw_exception(@_)
2632 # XXX: FIXME: Attributes docs need clearing up
2636 Attributes are used to refine a ResultSet in various ways when
2637 searching for data. They can be passed to any method which takes an
2638 C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
2641 These are in no particular order:
2647 =item Value: ( $order_by | \@order_by | \%order_by )
2651 Which column(s) to order the results by. If a single column name, or
2652 an arrayref of names is supplied, the argument is passed through
2653 directly to SQL. The hashref syntax allows for connection-agnostic
2654 specification of ordering direction:
2656 For descending order:
2658 order_by => { -desc => [qw/col1 col2 col3/] }
2660 For explicit ascending order:
2662 order_by => { -asc => 'col' }
2664 The old scalarref syntax (i.e. order_by => \'year DESC') is still
2665 supported, although you are strongly encouraged to use the hashref
2666 syntax as outlined above.
2672 =item Value: \@columns
2676 Shortcut to request a particular set of columns to be retrieved. Each
2677 column spec may be a string (a table column name), or a hash (in which
2678 case the key is the C<as> value, and the value is used as the C<select>
2679 expression). Adds C<me.> onto the start of any column without a C<.> in
2680 it and sets C<select> from that, then auto-populates C<as> from
2681 C<select> as normal. (You may also use the C<cols> attribute, as in
2682 earlier versions of DBIC.)
2688 =item Value: \@columns
2692 Indicates additional columns to be selected from storage. Works the same
2693 as L</columns> but adds columns to the selection. (You may also use the
2694 C<include_columns> attribute, as in earlier versions of DBIC). For
2697 $schema->resultset('CD')->search(undef, {
2698 '+columns' => ['artist.name'],
2702 would return all CDs and include a 'name' column to the information
2703 passed to object inflation. Note that the 'artist' is the name of the
2704 column (or relationship) accessor, and 'name' is the name of the column
2705 accessor in the related table.
2707 =head2 include_columns
2711 =item Value: \@columns
2715 Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
2721 =item Value: \@select_columns
2725 Indicates which columns should be selected from the storage. You can use
2726 column names, or in the case of RDBMS back ends, function or stored procedure
2729 $rs = $schema->resultset('Employee')->search(undef, {
2732 { count => 'employeeid' },
2737 When you use function/stored procedure names and do not supply an C<as>
2738 attribute, the column names returned are storage-dependent. E.g. MySQL would
2739 return a column named C<count(employeeid)> in the above example.
2745 Indicates additional columns to be selected from storage. Works the same as
2746 L</select> but adds columns to the selection.
2754 Indicates additional column names for those added via L</+select>. See L</as>.
2762 =item Value: \@inflation_names
2766 Indicates column names for object inflation. That is, C<as>
2767 indicates the name that the column can be accessed as via the
2768 C<get_column> method (or via the object accessor, B<if one already
2769 exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
2771 The C<as> attribute is used in conjunction with C<select>,
2772 usually when C<select> contains one or more function or stored
2775 $rs = $schema->resultset('Employee')->search(undef, {
2778 { count => 'employeeid' }
2780 as => ['name', 'employee_count'],
2783 my $employee = $rs->first(); # get the first Employee
2785 If the object against which the search is performed already has an accessor
2786 matching a column name specified in C<as>, the value can be retrieved using
2787 the accessor as normal:
2789 my $name = $employee->name();
2791 If on the other hand an accessor does not exist in the object, you need to
2792 use C<get_column> instead:
2794 my $employee_count = $employee->get_column('employee_count');
2796 You can create your own accessors if required - see
2797 L<DBIx::Class::Manual::Cookbook> for details.
2799 Please note: This will NOT insert an C<AS employee_count> into the SQL
2800 statement produced, it is used for internal access only. Thus
2801 attempting to use the accessor in an C<order_by> clause or similar
2802 will fail miserably.
2804 To get around this limitation, you can supply literal SQL to your
2805 C<select> attibute that contains the C<AS alias> text, eg:
2807 select => [\'myfield AS alias']
2813 =item Value: ($rel_name | \@rel_names | \%rel_names)
2817 Contains a list of relationships that should be joined for this query. For
2820 # Get CDs by Nine Inch Nails
2821 my $rs = $schema->resultset('CD')->search(
2822 { 'artist.name' => 'Nine Inch Nails' },
2823 { join => 'artist' }
2826 Can also contain a hash reference to refer to the other relation's relations.
2829 package MyApp::Schema::Track;
2830 use base qw/DBIx::Class/;
2831 __PACKAGE__->table('track');
2832 __PACKAGE__->add_columns(qw/trackid cd position title/);
2833 __PACKAGE__->set_primary_key('trackid');
2834 __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
2837 # In your application
2838 my $rs = $schema->resultset('Artist')->search(
2839 { 'track.title' => 'Teardrop' },
2841 join => { cd => 'track' },
2842 order_by => 'artist.name',
2846 You need to use the relationship (not the table) name in conditions,
2847 because they are aliased as such. The current table is aliased as "me", so
2848 you need to use me.column_name in order to avoid ambiguity. For example:
2850 # Get CDs from 1984 with a 'Foo' track
2851 my $rs = $schema->resultset('CD')->search(
2854 'tracks.name' => 'Foo'
2856 { join => 'tracks' }
2859 If the same join is supplied twice, it will be aliased to <rel>_2 (and
2860 similarly for a third time). For e.g.
2862 my $rs = $schema->resultset('Artist')->search({
2863 'cds.title' => 'Down to Earth',
2864 'cds_2.title' => 'Popular',
2866 join => [ qw/cds cds/ ],
2869 will return a set of all artists that have both a cd with title 'Down
2870 to Earth' and a cd with title 'Popular'.
2872 If you want to fetch related objects from other tables as well, see C<prefetch>
2875 For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
2881 =item Value: ($rel_name | \@rel_names | \%rel_names)
2885 Contains one or more relationships that should be fetched along with
2886 the main query (when they are accessed afterwards the data will
2887 already be available, without extra queries to the database). This is
2888 useful for when you know you will need the related objects, because it
2889 saves at least one query:
2891 my $rs = $schema->resultset('Tag')->search(
2900 The initial search results in SQL like the following:
2902 SELECT tag.*, cd.*, artist.* FROM tag
2903 JOIN cd ON tag.cd = cd.cdid
2904 JOIN artist ON cd.artist = artist.artistid
2906 L<DBIx::Class> has no need to go back to the database when we access the
2907 C<cd> or C<artist> relationships, which saves us two SQL statements in this
2910 Simple prefetches will be joined automatically, so there is no need
2911 for a C<join> attribute in the above search.
2913 C<prefetch> can be used with the following relationship types: C<belongs_to>,
2914 C<has_one> (or if you're using C<add_relationship>, any relationship declared
2915 with an accessor type of 'single' or 'filter'). A more complex example that
2916 prefetches an artists cds, the tracks on those cds, and the tags associted
2917 with that artist is given below (assuming many-to-many from artists to tags):
2919 my $rs = $schema->resultset('Artist')->search(
2923 { cds => 'tracks' },
2924 { artist_tags => 'tags' }
2930 B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
2931 attributes will be ignored.
2941 Makes the resultset paged and specifies the page to retrieve. Effectively
2942 identical to creating a non-pages resultset and then calling ->page($page)
2945 If L<rows> attribute is not specified it defualts to 10 rows per page.
2947 When you have a paged resultset, L</count> will only return the number
2948 of rows in the page. To get the total, use the L</pager> and call
2949 C<total_entries> on it.
2959 Specifes the maximum number of rows for direct retrieval or the number of
2960 rows per page if the page attribute or method is used.
2966 =item Value: $offset
2970 Specifies the (zero-based) row number for the first row to be returned, or the
2971 of the first row of the first page if paging is used.
2977 =item Value: \@columns
2981 A arrayref of columns to group by. Can include columns of joined tables.
2983 group_by => [qw/ column1 column2 ... /]
2989 =item Value: $condition
2993 HAVING is a select statement attribute that is applied between GROUP BY and
2994 ORDER BY. It is applied to the after the grouping calculations have been
2997 having => { 'count(employee)' => { '>=', 100 } }
3003 =item Value: (0 | 1)
3007 Set to 1 to group by all columns.
3013 Adds to the WHERE clause.
3015 # only return rows WHERE deleted IS NULL for all searches
3016 __PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
3018 Can be overridden by passing C<{ where => undef }> as an attribute
3025 Set to 1 to cache search results. This prevents extra SQL queries if you
3026 revisit rows in your ResultSet:
3028 my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
3030 while( my $artist = $resultset->next ) {
3034 $rs->first; # without cache, this would issue a query
3036 By default, searches are not cached.
3038 For more examples of using these attributes, see
3039 L<DBIx::Class::Manual::Cookbook>.
3045 =item Value: \@from_clause
3049 The C<from> attribute gives you manual control over the C<FROM> clause of SQL
3050 statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
3053 NOTE: Use this on your own risk. This allows you to shoot off your foot!
3055 C<join> will usually do what you need and it is strongly recommended that you
3056 avoid using C<from> unless you cannot achieve the desired result using C<join>.
3057 And we really do mean "cannot", not just tried and failed. Attempting to use
3058 this because you're having problems with C<join> is like trying to use x86
3059 ASM because you've got a syntax error in your C. Trust us on this.
3061 Now, if you're still really, really sure you need to use this (and if you're
3062 not 100% sure, ask the mailing list first), here's an explanation of how this
3065 The syntax is as follows -
3068 { <alias1> => <table1> },
3070 { <alias2> => <table2>, -join_type => 'inner|left|right' },
3071 [], # nested JOIN (optional)
3072 { <table1.column1> => <table2.column2>, ... (more conditions) },
3074 # More of the above [ ] may follow for additional joins
3081 ON <table1.column1> = <table2.column2>
3082 <more joins may follow>
3084 An easy way to follow the examples below is to remember the following:
3086 Anything inside "[]" is a JOIN
3087 Anything inside "{}" is a condition for the enclosing JOIN
3089 The following examples utilize a "person" table in a family tree application.
3090 In order to express parent->child relationships, this table is self-joined:
3092 # Person->belongs_to('father' => 'Person');
3093 # Person->belongs_to('mother' => 'Person');
3095 C<from> can be used to nest joins. Here we return all children with a father,
3096 then search against all mothers of those children:
3098 $rs = $schema->resultset('Person')->search(
3101 alias => 'mother', # alias columns in accordance with "from"
3103 { mother => 'person' },
3106 { child => 'person' },
3108 { father => 'person' },
3109 { 'father.person_id' => 'child.father_id' }
3112 { 'mother.person_id' => 'child.mother_id' }
3119 # SELECT mother.* FROM person mother
3122 # JOIN person father
3123 # ON ( father.person_id = child.father_id )
3125 # ON ( mother.person_id = child.mother_id )
3127 The type of any join can be controlled manually. To search against only people
3128 with a father in the person table, we could explicitly use C<INNER JOIN>:
3130 $rs = $schema->resultset('Person')->search(
3133 alias => 'child', # alias columns in accordance with "from"
3135 { child => 'person' },
3137 { father => 'person', -join_type => 'inner' },
3138 { 'father.id' => 'child.father_id' }
3145 # SELECT child.* FROM person child
3146 # INNER JOIN person father ON child.father_id = father.id
3148 If you need to express really complex joins or you need a subselect, you
3149 can supply literal SQL to C<from> via a scalar reference. In this case
3150 the contents of the scalar will replace the table name asscoiated with the
3153 WARNING: This technique might very well not work as expected on chained
3154 searches - you have been warned.
3156 # Assuming the Event resultsource is defined as:
3158 MySchema::Event->add_columns (
3161 is_auto_increment => 1,
3170 MySchema::Event->set_primary_key ('sequence');
3172 # This will get back the latest event for every location. The column
3173 # selector is still provided by DBIC, all we do is add a JOIN/WHERE
3174 # combo to limit the resultset
3176 $rs = $schema->resultset('Event');
3177 $table = $rs->result_source->name;
3178 $latest = $rs->search (
3181 (SELECT e1.* FROM $table e1
3183 ON e1.location = e2.location
3184 AND e1.sequence < e2.sequence
3185 WHERE e2.sequence is NULL
3190 # Equivalent SQL (with the DBIC chunks added):
3192 SELECT me.sequence, me.location, me.type FROM
3193 (SELECT e1.* FROM events e1
3195 ON e1.location = e2.location
3196 AND e1.sequence < e2.sequence
3197 WHERE e2.sequence is NULL
3204 =item Value: ( 'update' | 'shared' )
3208 Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT