use strict;
use warnings;
use overload
- '0+' => \&count,
- 'bool' => sub { 1; },
+ '0+' => "count",
+ 'bool' => "_bool",
fallback => 1;
use Carp::Clan qw/^DBIx::Class/;
use Data::Page;
use Storable;
use DBIx::Class::ResultSetColumn;
use DBIx::Class::ResultSourceHandle;
+use List::Util ();
+use Scalar::Util ();
use base qw/DBIx::Class/;
-__PACKAGE__->mk_group_accessors('simple' => qw/result_class _source_handle/);
+__PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
=head1 NAME
-DBIx::Class::ResultSet - Responsible for fetching and creating resultset.
+DBIx::Class::ResultSet - Represents a query used for fetching a set of results.
=head1 SYNOPSIS
- my $rs = $schema->resultset('User')->search(registered => 1);
- my @rows = $schema->resultset('CD')->search(year => 2005);
+ my $users_rs = $schema->resultset('User');
+ my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
+ my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
=head1 DESCRIPTION
-The resultset is also known as an iterator. It is responsible for handling
-queries that may return an arbitrary number of rows, e.g. via L</search>
-or a C<has_many> relationship.
+A ResultSet is an object which stores a set of conditions representing
+a query. It is the backbone of DBIx::Class (i.e. the really
+important/useful bit).
-In the examples below, the following table classes are used:
+No SQL is executed on the database when a ResultSet is created, it
+just stores all the conditions needed to create the query.
- package MyApp::Schema::Artist;
- use base qw/DBIx::Class/;
- __PACKAGE__->load_components(qw/Core/);
- __PACKAGE__->table('artist');
- __PACKAGE__->add_columns(qw/artistid name/);
- __PACKAGE__->set_primary_key('artistid');
- __PACKAGE__->has_many(cds => 'MyApp::Schema::CD');
- 1;
+A basic ResultSet representing the data of an entire table is returned
+by calling C<resultset> on a L<DBIx::Class::Schema> and passing in a
+L<Source|DBIx::Class::Manual::Glossary/Source> name.
- package MyApp::Schema::CD;
- use base qw/DBIx::Class/;
- __PACKAGE__->load_components(qw/Core/);
- __PACKAGE__->table('cd');
- __PACKAGE__->add_columns(qw/cdid artist title year/);
- __PACKAGE__->set_primary_key('cdid');
- __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Artist');
- 1;
+ my $users_rs = $schema->resultset('User');
+
+A new ResultSet is returned from calling L</search> on an existing
+ResultSet. The new one will contain all the conditions of the
+original, plus any new conditions added in the C<search> call.
+
+A ResultSet is also an iterator. L</next> is used to return all the
+L<DBIx::Class::Row>s the ResultSet represents.
+
+The query that the ResultSet represents is B<only> executed against
+the database when these methods are called:
+
+=over
+
+=item L</find>
+
+=item L</next>
+
+=item L</all>
+
+=item L</count>
+
+=item L</single>
+
+=item L</first>
+
+=back
+
+=head1 EXAMPLES
+
+=head2 Chaining resultsets
+
+Let's say you've got a query that needs to be run to return some data
+to the user. But, you have an authorization system in place that
+prevents certain users from seeing certain information. So, you want
+to construct the basic query in one method, but add constraints to it in
+another.
+
+ sub get_data {
+ my $self = shift;
+ my $request = $self->get_request; # Get a request object somehow.
+ my $schema = $self->get_schema; # Get the DBIC schema object somehow.
+
+ my $cd_rs = $schema->resultset('CD')->search({
+ title => $request->param('title'),
+ year => $request->param('year'),
+ });
+
+ $self->apply_security_policy( $cd_rs );
+
+ return $cd_rs->all();
+ }
+
+ sub apply_security_policy {
+ my $self = shift;
+ my ($rs) = @_;
+
+ return $rs->search({
+ subversive => 0,
+ });
+ }
+
+=head3 Resolving conditions and attributes
+
+When a resultset is chained from another resultset, conditions and
+attributes with the same keys need resolving.
+
+L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
+into the existing ones from the original resultset.
+
+The L</where>, L</having> attribute, and any search conditions are
+merged with an SQL C<AND> to the existing condition from the original
+resultset.
+
+All other attributes are overridden by any new ones supplied in the
+search attributes.
+
+=head2 Multiple queries
+
+Since a resultset just defines a query, you can do all sorts of
+things with it with the same object.
+
+ # Don't hit the DB yet.
+ my $cd_rs = $schema->resultset('CD')->search({
+ title => 'something',
+ year => 2009,
+ });
+
+ # Each of these hits the DB individually.
+ my $count = $cd_rs->count;
+ my $most_recent = $cd_rs->get_column('date_released')->max();
+ my @records = $cd_rs->all;
+
+And it's not just limited to SELECT statements.
+
+ $cd_rs->delete();
+
+This is even cooler:
+
+ $cd_rs->create({ artist => 'Fred' });
+
+Which is the same as:
+
+ $schema->resultset('CD')->create({
+ title => 'something',
+ year => 2009,
+ artist => 'Fred'
+ });
+
+See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
+
+=head1 OVERLOADING
+
+If a resultset is used in a numeric context it returns the L</count>.
+However, if it is used in a booleand context it is always true. So if
+you want to check if a resultset has any results use C<if $rs != 0>.
+C<if $rs> will always be true.
=head1 METHODS
return $class->new_result(@_) if ref $class;
my ($source, $attrs) = @_;
- $source = $source->handle
+ $source = $source->handle
unless $source->isa('DBIx::Class::ResultSourceHandle');
$attrs = { %{$attrs||{}} };
if ($attrs->{page}) {
$attrs->{rows} ||= 10;
- $attrs->{offset} ||= 0;
- $attrs->{offset} += ($attrs->{rows} * ($attrs->{page} - 1));
}
$attrs->{alias} ||= 'me';
+ # Creation of {} and bless separated to mitigate RH perl bug
+ # see https://bugzilla.redhat.com/show_bug.cgi?id=196836
my $self = {
_source_handle => $source,
- result_class => $attrs->{result_class} || $source->resolve->result_class,
cond => $attrs->{where},
count => undef,
pager => undef,
bless $self, $class;
+ $self->result_class(
+ $attrs->{result_class} || $source->resolve->result_class
+ );
+
return $self;
}
columns => [qw/name artistid/],
});
-For a list of attributes that can be passed to C<search>, see L</ATTRIBUTES>. For more examples of using this function, see L<Searching|DBIx::Class::Manual::Cookbook/Searching>.
+For a list of attributes that can be passed to C<search>, see
+L</ATTRIBUTES>. For more examples of using this function, see
+L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
+documentation for the first argument, see L<SQL::Abstract>.
+
+For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
=cut
sub search_rs {
my $self = shift;
- my $rows;
-
- unless (@_) { # no search, effectively just a clone
- $rows = $self->get_cache;
+ # Special-case handling for (undef, undef).
+ if ( @_ == 2 && !defined $_[1] && !defined $_[0] ) {
+ pop(@_); pop(@_);
}
my $attrs = {};
my $having = delete $our_attrs->{having};
my $where = delete $our_attrs->{where};
+ my $rows;
+
+ my %safe = (alias => 1, cache => 1);
+
+ unless (
+ (@_ && defined($_[0])) # @_ == () or (undef)
+ ||
+ (keys %$attrs # empty attrs or only 'safe' attrs
+ && List::Util::first { !$safe{$_} } keys %$attrs)
+ ) {
+ # no search, effectively just a clone
+ $rows = $self->get_cache;
+ }
+
my $new_attrs = { %{$our_attrs}, %{$attrs} };
# merge new attrs into inherited
- foreach my $key (qw/join prefetch/) {
+ foreach my $key (qw/join prefetch +select +as bind/) {
next unless exists $attrs->{$key};
$new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
}
: $having);
}
- my $rs = (ref $self)->new($self->_source_handle, $new_attrs);
+ my $rs = (ref $self)->new($self->result_source, $new_attrs);
if ($rows) {
$rs->set_cache($rows);
}
Pass a literal chunk of SQL to be added to the conditional part of the
resultset query.
+CAVEAT: C<search_literal> is provided for Class::DBI compatibility and should
+only be used in that context. C<search_literal> is a convenience method.
+It is equivalent to calling $schema->search(\[]), but if you want to ensure
+columns are bound correctly, use C<search>.
+
+Example of how to use C<search> instead of C<search_literal>
+
+ my @cds = $cd_rs->search_literal('cdid = ? AND (artist = ? OR artist = ?)', (2, 1, 2));
+ my @cds = $cd_rs->search(\[ 'cdid = ? AND (artist = ? OR artist = ?)', [ 'cdid', 2 ], [ 'artist', 1 ], [ 'artist', 2 ] ]);
+
+
+See L<DBIx::Class::Manual::Cookbook/Searching> and
+L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
+require C<search_literal>.
+
=cut
sub search_literal {
- my ($self, $cond, @vals) = @_;
- my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
- $attrs->{bind} = [ @{$self->{attrs}{bind}||[]}, @vals ];
- return $self->search(\$cond, $attrs);
+ my ($self, $sql, @bind) = @_;
+ my $attr;
+ if ( @bind && ref($bind[-1]) eq 'HASH' ) {
+ $attr = pop @bind;
+ }
+ return $self->search(\[ $sql, map [ __DUMMY__ => $_ ], @bind ], ($attr || () ));
}
=head2 find
=item Arguments: @values | \%cols, \%attrs?
-=item Return Value: $row_object
+=item Return Value: $row_object | undef
=back
If the C<key> is specified as C<primary>, it searches only on the primary key.
If no C<key> is specified, it searches on all unique constraints defined on the
-source, including the primary key.
+source for which column data is provided, including the primary key.
If your table does not have a primary key, you B<must> provide a value for the
C<key> attribute matching one of the unique constraints on the source.
+In addition to C<key>, L</find> recognizes and applies standard
+L<resultset attributes|/ATTRIBUTES> in the same way as L</search> does.
+
+Note: If your query does not return only one row, a warning is generated:
+
+ Query returned more than one row
+
See also L</find_or_create> and L</update_or_create>. For information on how to
declare unique constraints, see
L<DBIx::Class::ResultSource/add_unique_constraint>.
my (%related, $info);
- foreach my $key (keys %$input_query) {
+ KEY: foreach my $key (keys %$input_query) {
if (ref($input_query->{$key})
&& ($info = $self->result_source->relationship_info($key))) {
- my $rel_q = $self->result_source->resolve_condition(
- $info->{cond}, delete $input_query->{$key}, $key
+ my $val = delete $input_query->{$key};
+ next KEY if (ref($val) eq 'ARRAY'); # has_many for multi_create
+ my $rel_q = $self->result_source->_resolve_condition(
+ $info->{cond}, $val, $key
);
die "Can't handle OR join condition in find" if ref($rel_q) eq 'ARRAY';
@related{keys %$rel_q} = values %$rel_q;
@{$input_query}{@keys} = values %related;
}
- my @unique_queries = $self->_unique_queries($input_query, $attrs);
# Build the final query: Default to the disjunction of the unique queries,
# but allow the input query in case the ResultSet defines the query or the
# user is abusing find
my $alias = exists $attrs->{alias} ? $attrs->{alias} : $self->{attrs}{alias};
- my $query = @unique_queries
- ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
- : $self->_add_alias($input_query, $alias);
+ my $query;
+ if (exists $attrs->{key}) {
+ my @unique_cols = $self->result_source->unique_constraint_columns($attrs->{key});
+ my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
+ $query = $self->_add_alias($unique_query, $alias);
+ }
+ else {
+ my @unique_queries = $self->_unique_queries($input_query, $attrs);
+ $query = @unique_queries
+ ? [ map { $self->_add_alias($_, $alias) } @unique_queries ]
+ : $self->_add_alias($input_query, $alias);
+ }
# Run the query
if (keys %$attrs) {
my $rs = $self->search($query, $attrs);
- return keys %{$rs->_resolved_attrs->{collapse}} ? $rs->next : $rs->single;
+ if (keys %{$rs->_resolved_attrs->{collapse}}) {
+ my $row = $rs->next;
+ carp "Query returned more than one row" if $rs->next;
+ return $row;
+ }
+ else {
+ return $rs->single;
+ }
}
else {
- return keys %{$self->_resolved_attrs->{collapse}}
- ? $self->search($query)->next
- : $self->single($query);
+ if (keys %{$self->_resolved_attrs->{collapse}}) {
+ my $rs = $self->search($query);
+ my $row = $rs->next;
+ carp "Query returned more than one row" if $rs->next;
+ return $row;
+ }
+ else {
+ return $self->single($query);
+ }
}
}
return shift->related_resultset(shift)->search(@_);
}
+=head2 search_related_rs
+
+This method works exactly the same as search_related, except that
+it guarantees a restultset, even in list context.
+
+=cut
+
+sub search_related_rs {
+ return shift->related_resultset(shift)->search_rs(@_);
+}
+
=head2 cursor
=over 4
my $cd = $schema->resultset('CD')->single({ year => 2001 });
Inflates the first result without creating a cursor if the resultset has
-any records in it; if not returns nothing. Used by L</find> as an optimisation.
+any records in it; if not returns nothing. Used by L</find> as a lean version of
+L</search>.
-Can optionally take an additional condition *only* - this is a fast-code-path
-method; if you need to add extra joins or similar call ->search and then
-->single without a condition on the $rs returned from that.
+While this method can take an optional search condition (just like L</search>)
+being a fast-code-path it does not recognize search attributes. If you need to
+add extra joins or similar, call L</search> and then chain-call L</single> on the
+L<DBIx::Class::ResultSet> returned.
+
+=over
+
+=item B<Note>
+
+As of 0.08100, this method enforces the assumption that the preceeding
+query returns only one row. If more than one row is returned, you will receive
+a warning:
+
+ Query returned more than one row
+
+In this case, you should be using L</first> or L</find> instead, or if you really
+know what you are doing, use the L</rows> attribute to explicitly limit the size
+of the resultset.
+
+=back
=cut
sub single {
my ($self, $where) = @_;
+ if(@_ > 2) {
+ $self->throw_exception('single() only takes search conditions, no attributes. You want ->search( $cond, $attrs )->single()');
+ }
+
my $attrs = { %{$self->_resolved_attrs} };
if ($where) {
if (defined $attrs->{where}) {
$attrs->{where}, $attrs
);
- return (@data ? ($self->_construct_object(@data))[0] : ());
+ return (@data ? ($self->_construct_object(@data))[0] : undef);
}
# _is_unique_query
if (ref $query eq 'ARRAY') {
foreach my $subquery (@$query) {
next unless ref $subquery; # -or
-# warn "ARRAY: " . Dumper $subquery;
$collapsed = $self->_collapse_query($subquery, $collapsed);
}
}
elsif (ref $query eq 'HASH') {
if (keys %$query and (keys %$query)[0] eq '-and') {
foreach my $subquery (@{$query->{-and}}) {
-# warn "HASH: " . Dumper $subquery;
$collapsed = $self->_collapse_query($subquery, $collapsed);
}
}
else {
-# warn "LEAF: " . Dumper $query;
foreach my $col (keys %$query) {
my $value = $query->{$col};
$collapsed->{$col}{$value}++;
$cd_rs = $rs->search_like({ title => '%blue%'});
Performs a search, but uses C<LIKE> instead of C<=> as the condition. Note
-that this is simply a convenience method. You most likely want to use
-L</search> with specific operators.
+that this is simply a convenience method retained for ex Class::DBI users.
+You most likely want to use L</search> with specific operators.
For more information, see L<DBIx::Class::Manual::Cookbook>.
+This method is deprecated and will be removed in 0.09. Use L</search()>
+instead. An example conversion is:
+
+ ->search_like({ foo => 'bar' });
+
+ # Becomes
+
+ ->search({ foo => { like => 'bar' } });
+
=cut
sub search_like {
my $class = shift;
+ carp join ("\n",
+ 'search_like() is deprecated and will be removed in 0.09.',
+ 'Instead use ->search({ x => { -like => "y%" } })',
+ '(note the outer pair of {}s - they are important!)'
+ );
my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
$query->{$_} = { 'like' => $query->{$_} } for keys %$query;
? @{delete $self->{stashed_row}}
: $self->cursor->next
);
- return unless (@row);
+ return undef unless (@row);
my ($row, @more) = $self->_construct_object(@row);
$self->{stashed_objects} = \@more if @more;
return $row;
sub _construct_object {
my ($self, @row) = @_;
my $info = $self->_collapse_result($self->{_attrs}{as}, \@row);
- my @new = $self->result_class->inflate_result($self->_source_handle, @$info);
+ my @new = $self->result_class->inflate_result($self->result_source, @$info);
@new = $self->{_attrs}{record_filter}->(@new)
if exists $self->{_attrs}{record_filter};
return @new;
}
sub _collapse_result {
- my ($self, $as, $row, $prefix) = @_;
+ my ($self, $as_proto, $row) = @_;
- my %const;
my @copy = @$row;
-
- foreach my $this_as (@$as) {
- my $val = shift @copy;
- if (defined $prefix) {
- if ($this_as =~ m/^\Q${prefix}.\E(.+)$/) {
- my $remain = $1;
- $remain =~ /^(?:(.*)\.)?([^.]+)$/;
- $const{$1||''}{$2} = $val;
- }
- } else {
- $this_as =~ /^(?:(.*)\.)?([^.]+)$/;
- $const{$1||''}{$2} = $val;
- }
- }
- my $alias = $self->{attrs}{alias};
- my $info = [ {}, {} ];
- foreach my $key (keys %const) {
- if (length $key && $key ne $alias) {
- my $target = $info;
- my @parts = split(/\./, $key);
- foreach my $p (@parts) {
- $target = $target->[1]->{$p} ||= [];
+ # 'foo' => [ undef, 'foo' ]
+ # 'foo.bar' => [ 'foo', 'bar' ]
+ # 'foo.bar.baz' => [ 'foo.bar', 'baz' ]
+
+ my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto;
+
+ my %collapse = %{$self->{_attrs}{collapse}||{}};
+
+ my @pri_index;
+
+ # if we're doing collapsing (has_many prefetch) we need to grab records
+ # until the PK changes, so fill @pri_index. if not, we leave it empty so
+ # we know we don't have to bother.
+
+ # the reason for not using the collapse stuff directly is because if you
+ # had for e.g. two artists in a row with no cds, the collapse info for
+ # both would be NULL (undef) so you'd lose the second artist
+
+ # store just the index so we can check the array positions from the row
+ # without having to contruct the full hash
+
+ if (keys %collapse) {
+ my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
+ foreach my $i (0 .. $#construct_as) {
+ next if defined($construct_as[$i][0]); # only self table
+ if (delete $pri{$construct_as[$i][1]}) {
+ push(@pri_index, $i);
}
- $target->[0] = $const{$key};
- } else {
- $info->[0] = $const{$key};
+ last unless keys %pri; # short circuit (Johnny Five Is Alive!)
}
}
-
- my @collapse;
- if (defined $prefix) {
- @collapse = map {
- m/^\Q${prefix}.\E(.+)$/ ? ($1) : ()
- } keys %{$self->{_attrs}{collapse}}
- } else {
- @collapse = keys %{$self->{_attrs}{collapse}};
- };
- if (@collapse) {
- my ($c) = sort { length $a <=> length $b } @collapse;
- my $target = $info;
- foreach my $p (split(/\./, $c)) {
- $target = $target->[1]->{$p} ||= [];
+ # no need to do an if, it'll be empty if @pri_index is empty anyway
+
+ my %pri_vals = map { ($_ => $copy[$_]) } @pri_index;
+
+ my @const_rows;
+
+ do { # no need to check anything at the front, we always want the first row
+
+ my %const;
+
+ foreach my $this_as (@construct_as) {
+ $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy);
}
- my $c_prefix = (defined($prefix) ? "${prefix}.${c}" : $c);
- my @co_key = @{$self->{_attrs}{collapse}{$c_prefix}};
- my $tree = $self->_collapse_result($as, $row, $c_prefix);
- my %co_check = map { ($_, $tree->[0]->{$_}); } @co_key;
- my (@final, @raw);
-
- while (
- !(
+
+ push(@const_rows, \%const);
+
+ } until ( # no pri_index => no collapse => drop straight out
+ !@pri_index
+ or
+ do { # get another row, stash it, drop out if different PK
+
+ @copy = $self->cursor->next;
+ $self->{stashed_row} = \@copy;
+
+ # last thing in do block, counts as true if anything doesn't match
+
+ # check xor defined first for NULL vs. NOT NULL then if one is
+ # defined the other must be so check string equality
+
grep {
- !defined($tree->[0]->{$_}) || $co_check{$_} ne $tree->[0]->{$_}
- } @co_key
- )
- ) {
- push(@final, $tree);
- last unless (@raw = $self->cursor->next);
- $row = $self->{stashed_row} = \@raw;
- $tree = $self->_collapse_result($as, $row, $c_prefix);
+ (defined $pri_vals{$_} ^ defined $copy[$_])
+ || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_]))
+ } @pri_index;
+ }
+ );
+
+ my $alias = $self->{attrs}{alias};
+ my $info = [];
+
+ my %collapse_pos;
+
+ my @const_keys;
+
+ foreach my $const (@const_rows) {
+ scalar @const_keys or do {
+ @const_keys = sort { length($a) <=> length($b) } keys %$const;
+ };
+ foreach my $key (@const_keys) {
+ if (length $key) {
+ my $target = $info;
+ my @parts = split(/\./, $key);
+ my $cur = '';
+ my $data = $const->{$key};
+ foreach my $p (@parts) {
+ $target = $target->[1]->{$p} ||= [];
+ $cur .= ".${p}";
+ if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) {
+ # collapsing at this point and on final part
+ my $pos = $collapse_pos{$cur};
+ CK: foreach my $ck (@ckey) {
+ if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) {
+ $collapse_pos{$cur} = $data;
+ delete @collapse_pos{ # clear all positioning for sub-entries
+ grep { m/^\Q${cur}.\E/ } keys %collapse_pos
+ };
+ push(@$target, []);
+ last CK;
+ }
+ }
+ }
+ if (exists $collapse{$cur}) {
+ $target = $target->[-1];
+ }
+ }
+ $target->[0] = $data;
+ } else {
+ $info->[0] = $const->{$key};
+ }
}
- @$target = (@final ? @final : [ {}, {} ]);
- # single empty result to indicate an empty prefetched has_many
}
- #print "final info: " . Dumper($info);
return $info;
}
=back
-An accessor for the class to use when creating row objects. Defaults to
-C<< result_source->result_class >> - which in most cases is the name of the
+An accessor for the class to use when creating row objects. Defaults to
+C<< result_source->result_class >> - which in most cases is the name of the
L<"table"|DBIx::Class::Manual::Glossary/"ResultSource"> class.
+Note that changing the result_class will also remove any components
+that were originally loaded in the source class via
+L<DBIx::Class::ResultSource/load_components>. Any overloaded methods
+in the original source class will not run.
+
=cut
+sub result_class {
+ my ($self, $result_class) = @_;
+ if ($result_class) {
+ $self->ensure_class_loaded($result_class);
+ $self->_result_class($result_class);
+ }
+ $self->_result_class;
+}
=head2 count
with to find the number of elements. If passed arguments, does a search
on the resultset and counts the results of that.
-Note: When using C<count> with C<group_by>, L<DBIX::Class> emulates C<GROUP BY>
-using C<COUNT( DISTINCT( columns ) )>. Some databases (notably SQLite) do
-not support C<DISTINCT> with multiple columns. If you are using such a
-database, you should only use columns from the main table in your C<group_by>
-clause.
-
=cut
sub count {
my $self = shift;
return $self->search(@_)->count if @_ and defined $_[0];
return scalar @{ $self->get_cache } if $self->get_cache;
- my $count = $self->_count;
- return 0 unless $count;
- $count -= $self->{attrs}{offset} if $self->{attrs}{offset};
- $count = $self->{attrs}{rows} if
- $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
- return $count;
+ my @subq_attrs = qw/prefetch collapse distinct group_by having/;
+ my $attrs = $self->_resolved_attrs;
+
+ # if we are not paged - we are simply asking for a limit
+ if (not $attrs->{page} and not $attrs->{software_limit}) {
+ push @subq_attrs, qw/rows offset/;
+ }
+
+ return $self->_has_attr (@subq_attrs)
+ ? $self->_count_subq
+ : $self->_count_simple
}
-sub _count { # Separated out so pager can get the full count
+sub _count_subq {
my $self = shift;
- my $select = { count => '*' };
my $attrs = { %{$self->_resolved_attrs} };
- if (my $group_by = delete $attrs->{group_by}) {
- delete $attrs->{having};
- my @distinct = (ref $group_by ? @$group_by : ($group_by));
- # todo: try CONCAT for multi-column pk
- my @pk = $self->result_source->primary_columns;
- if (@pk == 1) {
- my $alias = $attrs->{alias};
- foreach my $column (@distinct) {
- if ($column =~ qr/^(?:\Q${alias}.\E)?$pk[0]$/) {
- @distinct = ($column);
- last;
- }
- }
- }
- $select = { count => { distinct => \@distinct } };
- }
+ # copy for the subquery, we need to do some adjustments to it too
+ my $sub_attrs = { %$attrs };
- $attrs->{select} = $select;
- $attrs->{as} = [qw/count/];
+ # these can not go in the subquery either
+ delete $sub_attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns/;
+
+ # force a group_by and the same set of columns (most databases require this)
+ $sub_attrs->{columns} = $sub_attrs->{group_by} ||= [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
+
+ $attrs->{from} = [{
+ count_subq => (ref $self)->new ($self->result_source, $sub_attrs )->as_query
+ }];
+
+ # the subquery replaces this
+ delete $attrs->{$_} for qw/where bind prefetch collapse distinct group_by having having_bind/;
+
+ return $self->__count ($attrs);
+}
+
+sub _count_simple {
+ my $self = shift;
+
+ my $count = $self->__count;
+ return 0 unless $count;
+
+ # need to take offset from resolved attrs
+
+ my $attrs = $self->_resolved_attrs;
+
+ $count -= $attrs->{offset} if $attrs->{offset};
+ $count = $attrs->{rows} if $attrs->{rows} and $attrs->{rows} < $count;
+ $count = 0 if ($count < 0);
+ return $count;
+}
+
+sub __count {
+ my ($self, $attrs) = @_;
- # offset, order by and page are not needed to count. record_filter is cdbi
- delete $attrs->{$_} for qw/rows offset order_by page pager record_filter/;
+ $attrs ||= { %{$self->_resolved_attrs} };
- my $tmp_rs = (ref $self)->new($self->_source_handle, $attrs);
+ # take off any column specs, any pagers, record_filter is cdbi, and no point of ordering a count
+ delete $attrs->{$_} for (qw/columns +columns select +select as +as rows offset page pager order_by record_filter/);
+
+ $attrs->{select} = { count => '*' };
+ $attrs->{as} = [qw/count/];
+
+ my $tmp_rs = (ref $self)->new($self->result_source, $attrs);
my ($count) = $tmp_rs->cursor->next;
+
return $count;
}
+sub _bool {
+ return 1;
+}
+
=head2 count_literal
=over 4
=cut
sub all {
- my ($self) = @_;
+ my $self = shift;
+ if(@_) {
+ $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
+ }
+
return @{ $self->get_cache } if $self->get_cache;
my @obj;
return $_[0]->reset->next;
}
+
+# _rs_update_delete
+#
+# Determines whether and what type of subquery is required for the $rs operation.
+# If grouping is necessary either supplies its own, or verifies the current one
+# After all is done delegates to the proper storage method.
+
+sub _rs_update_delete {
+ my ($self, $op, $values) = @_;
+
+ my $rsrc = $self->result_source;
+
+ my $needs_group_by_subq = $self->_has_attr (qw/prefetch distinct join seen_join group_by/);
+ my $needs_subq = $self->_has_attr (qw/row offset page/);
+
+ if ($needs_group_by_subq or $needs_subq) {
+
+ # make a new $rs selecting only the PKs (that's all we really need)
+ my $attrs = $self->_resolved_attrs;
+
+ delete $attrs->{$_} for qw/prefetch collapse select +select as +as columns +columns/;
+ $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
+
+ if ($needs_group_by_subq) {
+ # make sure no group_by was supplied, or if there is one - make sure it matches
+ # the columns compiled above perfectly. Anything else can not be sanely executed
+ # on most databases so croak right then and there
+
+ if (my $g = $attrs->{group_by}) {
+ my @current_group_by = map
+ { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" }
+ (ref $g eq 'ARRAY' ? @$g : $g );
+
+ if (
+ join ("\x00", sort @current_group_by)
+ ne
+ join ("\x00", sort @{$attrs->{columns}} )
+ ) {
+ $self->throw_exception (
+ "You have just attempted a $op operation on a resultset which does group_by"
+ . ' on columns other than the primary keys, while DBIC internally needs to retrieve'
+ . ' the primary keys in a subselect. All sane RDBMS engines do not support this'
+ . ' kind of queries. Please retry the operation with a modified group_by or'
+ . ' without using one at all.'
+ );
+ }
+ }
+ else {
+ $attrs->{group_by} = $attrs->{columns};
+ }
+ }
+
+ my $subrs = (ref $self)->new($rsrc, $attrs);
+
+ return $self->result_source->storage->subq_update_delete($subrs, $op, $values);
+ }
+ else {
+ return $rsrc->storage->$op(
+ $rsrc,
+ $op eq 'update' ? $values : (),
+ $self->_cond_for_update_delete,
+ );
+ }
+}
+
+
# _cond_for_update_delete
#
# update/delete require the condition to be modified to handle
elsif (ref $full_cond eq 'HASH') {
if ((keys %{$full_cond})[0] eq '-and') {
$cond->{-and} = [];
-
my @cond = @{$full_cond->{-and}};
- for (my $i = 0; $i < @cond; $i++) {
+ for (my $i = 0; $i < @cond; $i++) {
my $entry = $cond[$i];
-
my $hash;
if (ref $entry eq 'HASH') {
$hash = $self->_cond_for_update_delete($entry);
$entry =~ /([^.]+)$/;
$hash->{$1} = $cond[++$i];
}
-
push @{$cond->{-and}}, $hash;
}
}
}
}
else {
- $self->throw_exception(
- "Can't update/delete on resultset with condition unless hash or array"
- );
+ $self->throw_exception("Can't update/delete on resultset with condition unless hash or array");
}
return $cond;
sub update {
my ($self, $values) = @_;
- $self->throw_exception("Values for update must be a hash")
+ $self->throw_exception('Values for update must be a hash')
unless ref $values eq 'HASH';
- my $cond = $self->_cond_for_update_delete;
-
- return $self->result_source->storage->update(
- $self->result_source, $values, $cond
- );
+ return $self->_rs_update_delete ('update', $values);
}
=head2 update_all
sub update_all {
my ($self, $values) = @_;
- $self->throw_exception("Values for update must be a hash")
+ $self->throw_exception('Values for update_all must be a hash')
unless ref $values eq 'HASH';
foreach my $obj ($self->all) {
$obj->set_columns($values)->update;
will not run DBIC cascade triggers. See L</delete_all> if you need triggers
to run. See also L<DBIx::Class::Row/delete>.
+delete may not generate correct SQL for a query with joins or a resultset
+chained from a related resultset. In this case it will generate a warning:-
+
+In these cases you may find that delete_all is more appropriate, or you
+need to respecify your query in a way that can be expressed without a join.
+
=cut
sub delete {
- my ($self) = @_;
-
- my $cond = $self->_cond_for_update_delete;
+ my $self = shift;
+ $self->throw_exception('delete does not accept any arguments')
+ if @_;
- $self->result_source->storage->delete($self->result_source, $cond);
- return 1;
+ return $self->_rs_update_delete ('delete');
}
=head2 delete_all
=cut
sub delete_all {
- my ($self) = @_;
+ my $self = shift;
+ $self->throw_exception('delete_all does not accept any arguments')
+ if @_;
+
$_->delete for $self->all;
return 1;
}
+=head2 populate
+
+=over 4
+
+=item Arguments: \@data;
+
+=back
+
+Accepts either an arrayref of hashrefs or alternatively an arrayref of arrayrefs.
+For the arrayref of hashrefs style each hashref should be a structure suitable
+forsubmitting to a $resultset->create(...) method.
+
+In void context, C<insert_bulk> in L<DBIx::Class::Storage::DBI> is used
+to insert the data, as this is a faster method.
+
+Otherwise, each set of data is inserted into the database using
+L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
+objects is returned.
+
+Example: Assuming an Artist Class that has many CDs Classes relating:
+
+ my $Artist_rs = $schema->resultset("Artist");
+
+ ## Void Context Example
+ $Artist_rs->populate([
+ { artistid => 4, name => 'Manufactured Crap', cds => [
+ { title => 'My First CD', year => 2006 },
+ { title => 'Yet More Tweeny-Pop crap', year => 2007 },
+ ],
+ },
+ { artistid => 5, name => 'Angsty-Whiny Girl', cds => [
+ { title => 'My parents sold me to a record company' ,year => 2005 },
+ { title => 'Why Am I So Ugly?', year => 2006 },
+ { title => 'I Got Surgery and am now Popular', year => 2007 }
+ ],
+ },
+ ]);
+
+ ## Array Context Example
+ my ($ArtistOne, $ArtistTwo, $ArtistThree) = $Artist_rs->populate([
+ { name => "Artist One"},
+ { name => "Artist Two"},
+ { name => "Artist Three", cds=> [
+ { title => "First CD", year => 2007},
+ { title => "Second CD", year => 2008},
+ ]}
+ ]);
+
+ print $ArtistOne->name; ## response is 'Artist One'
+ print $ArtistThree->cds->count ## reponse is '2'
+
+For the arrayref of arrayrefs style, the first element should be a list of the
+fieldsnames to which the remaining elements are rows being inserted. For
+example:
+
+ $Arstist_rs->populate([
+ [qw/artistid name/],
+ [100, 'A Formally Unknown Singer'],
+ [101, 'A singer that jumped the shark two albums ago'],
+ [102, 'An actually cool singer.'],
+ ]);
+
+Please note an important effect on your data when choosing between void and
+wantarray context. Since void context goes straight to C<insert_bulk> in
+L<DBIx::Class::Storage::DBI> this will skip any component that is overriding
+C<insert>. So if you are using something like L<DBIx-Class-UUIDColumns> to
+create primary keys for you, you will find that your PKs are empty. In this
+case you will have to use the wantarray context in order to create those
+values.
+
+=cut
+
+sub populate {
+ my $self = shift @_;
+ my $data = ref $_[0][0] eq 'HASH'
+ ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
+ $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
+
+ if(defined wantarray) {
+ my @created;
+ foreach my $item (@$data) {
+ push(@created, $self->create($item));
+ }
+ return @created;
+ } else {
+ my ($first, @rest) = @$data;
+
+ my @names = grep {!ref $first->{$_}} keys %$first;
+ my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
+ my @pks = $self->result_source->primary_columns;
+
+ ## do the belongs_to relationships
+ foreach my $index (0..$#$data) {
+ if( grep { !defined $data->[$index]->{$_} } @pks ) {
+ my @ret = $self->populate($data);
+ return;
+ }
+
+ foreach my $rel (@rels) {
+ next unless $data->[$index]->{$rel} && ref $data->[$index]->{$rel} eq "HASH";
+ my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
+ my ($reverse) = keys %{$self->result_source->reverse_relationship_info($rel)};
+ my $related = $result->result_source->_resolve_condition(
+ $result->result_source->relationship_info($reverse)->{cond},
+ $self,
+ $result,
+ );
+
+ delete $data->[$index]->{$rel};
+ $data->[$index] = {%{$data->[$index]}, %$related};
+
+ push @names, keys %$related if $index == 0;
+ }
+ }
+
+ ## do bulk insert on current row
+ my @values = map { [ @$_{@names} ] } @$data;
+
+ $self->result_source->storage->insert_bulk(
+ $self->result_source,
+ \@names,
+ \@values,
+ );
+
+ ## do the has_many relationships
+ foreach my $item (@$data) {
+
+ foreach my $rel (@rels) {
+ next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
+
+ my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
+ || $self->throw_exception('Cannot find the relating object.');
+
+ my $child = $parent->$rel;
+
+ my $related = $child->result_source->_resolve_condition(
+ $parent->result_source->relationship_info($rel)->{cond},
+ $child,
+ $parent,
+ );
+
+ my @rows_to_add = ref $item->{$rel} eq 'ARRAY' ? @{$item->{$rel}} : ($item->{$rel});
+ my @populate = map { {%$_, %$related} } @rows_to_add;
+
+ $child->populate( \@populate );
+ }
+ }
+ }
+}
+
+=head2 _normalize_populate_args ($args)
+
+Private method used by L</populate> to normalize its incoming arguments. Factored
+out in case you want to subclass and accept new argument structures to the
+L</populate> method.
+
+=cut
+
+sub _normalize_populate_args {
+ my ($self, $data) = @_;
+ my @names = @{shift(@$data)};
+ my @results_to_create;
+ foreach my $datum (@$data) {
+ my %result_to_create;
+ foreach my $index (0..$#names) {
+ $result_to_create{$names[$index]} = $$datum[$index];
+ }
+ push @results_to_create, \%result_to_create;
+ }
+ return \@results_to_create;
+}
+
=head2 pager
=over 4
Return Value a L<Data::Page> object for the current resultset. Only makes
sense for queries with a C<page> attribute.
+To get the full count of entries for a paged resultset, call
+C<total_entries> on the L<Data::Page> object.
+
=cut
sub pager {
my ($self) = @_;
+
+ return $self->{pager} if $self->{pager};
+
my $attrs = $self->{attrs};
$self->throw_exception("Can't create pager for non-paged rs")
unless $self->{attrs}{page};
$attrs->{rows} ||= 10;
- return $self->{pager} ||= Data::Page->new(
- $self->_count, $attrs->{rows}, $self->{attrs}{page});
+
+ # throw away the paging flags and re-run the count (possibly
+ # with a subselect) to get the real total count
+ my $count_attrs = { %$attrs };
+ delete $count_attrs->{$_} for qw/rows offset page pager/;
+ my $total_count = (ref $self)->new($self->result_source, $count_attrs)->count;
+
+ return $self->{pager} = Data::Page->new(
+ $total_count,
+ $attrs->{rows},
+ $self->{attrs}{page}
+ );
}
=head2 page
sub page {
my ($self, $page) = @_;
- return (ref $self)->new($self->_source_handle, { %{$self->{attrs}}, page => $page });
+ return (ref $self)->new($self->result_source, { %{$self->{attrs}}, page => $page });
}
=head2 new_result
=item Arguments: \%vals
-=item Return Value: $object
+=item Return Value: $rowobject
=back
-Creates an object in the resultset's result class and returns it.
+Creates a new row object in the resultset's result class and returns
+it. The row is not inserted into the database at this point, call
+L<DBIx::Class::Row/insert> to do that. Calling L<DBIx::Class::Row/in_storage>
+will tell you whether the row object has been inserted or not.
+
+Passes the hashref of input on to L<DBIx::Class::Row/new>.
=cut
my ($self, $values) = @_;
$self->throw_exception( "new_result needs a hash" )
unless (ref $values eq 'HASH');
- $self->throw_exception(
- "Can't abstract implicit construct, condition not a hash"
- ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
+ my %new;
my $alias = $self->{attrs}{alias};
- my $collapsed_cond = $self->{cond} ? $self->_collapse_cond($self->{cond}) : {};
- my %new = (
+
+ if (
+ defined $self->{cond}
+ && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
+ ) {
+ %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
+ $new{-from_resultset} = [ keys %new ] if keys %new;
+ } else {
+ $self->throw_exception(
+ "Can't abstract implicit construct, condition not a hash"
+ ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
+
+ my $collapsed_cond = (
+ $self->{cond}
+ ? $self->_collapse_cond($self->{cond})
+ : {}
+ );
+
+ # precendence must be given to passed values over values inherited from
+ # the cond, so the order here is important.
+ my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
+ while( my($col,$value) = each %implied ){
+ if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
+ $new{$col} = $value->{'='};
+ next;
+ }
+ $new{$col} = $value if $self->_is_deterministic_value($value);
+ }
+ }
+
+ %new = (
+ %new,
%{ $self->_remove_alias($values, $alias) },
- %{ $self->_remove_alias($collapsed_cond, $alias) },
+ -source_handle => $self->_source_handle,
+ -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
+ );
+
+ return $self->result_class->new(\%new);
+}
+
+# _is_deterministic_value
+#
+# Make an effor to strip non-deterministic values from the condition,
+# to make sure new_result chokes less
+
+sub _is_deterministic_value {
+ my $self = shift;
+ my $value = shift;
+ my $ref_type = ref $value;
+ return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
+ return 1 if Scalar::Util::blessed($value);
+ return 0;
+}
+
+# _has_attr
+#
+# determines if the resultset defines at least one
+# of the attributes supplied
+#
+# used to determine if a subquery is neccessary
+
+sub _has_attr {
+ my ($self, @attr_names) = @_;
+
+ my $attrs = $self->_resolved_attrs;
+
+ my $join_check_req;
+
+ for my $n (@attr_names) {
+ ++$join_check_req if $n =~ /join/;
+
+ my $attr = $attrs->{$n};
+
+ next if not defined $attr;
+
+ if (ref $attr eq 'HASH') {
+ return 1 if keys %$attr;
+ }
+ elsif (ref $attr eq 'ARRAY') {
+ return 1 if @$attr;
+ }
+ else {
+ return 1 if $attr;
+ }
+ }
+
+ # a join can be expressed as a multi-level from
+ return 1 if (
+ $join_check_req
+ and
+ ref $attrs->{from} eq 'ARRAY'
+ and
+ @{$attrs->{from}} > 1
);
- return $self->result_class->new(\%new,$self->_source_handle);
+ return 0;
}
# _collapse_cond
if (ref $cond eq 'ARRAY') {
foreach my $subcond (@$cond) {
next unless ref $subcond; # -or
-# warn "ARRAY: " . Dumper $subcond;
$collapsed = $self->_collapse_cond($subcond, $collapsed);
}
}
elsif (ref $cond eq 'HASH') {
if (keys %$cond and (keys %$cond)[0] eq '-and') {
foreach my $subcond (@{$cond->{-and}}) {
-# warn "HASH: " . Dumper $subcond;
$collapsed = $self->_collapse_cond($subcond, $collapsed);
}
}
else {
-# warn "LEAF: " . Dumper $cond;
foreach my $col (keys %$cond) {
my $value = $cond->{$col};
$collapsed->{$col} = $value;
return \%unaliased;
}
+=head2 as_query (EXPERIMENTAL)
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: \[ $sql, @bind ]
+
+=back
+
+Returns the SQL query and bind vars associated with the invocant.
+
+This is generally used as the RHS for a subquery.
+
+B<NOTE>: This feature is still experimental.
+
+=cut
+
+sub as_query { return shift->cursor->as_query(@_) }
+
=head2 find_or_new
=over 4
=item Arguments: \%vals, \%attrs?
-=item Return Value: $object
+=item Return Value: $rowobject
=back
-Find an existing record from this resultset. If none exists, instantiate a new
-result object and return it. The object will not be saved into your storage
+ my $artist = $schema->resultset('Artist')->find_or_new(
+ { artist => 'fred' }, { key => 'artists' });
+
+ $cd->cd_to_producer->find_or_new({ producer => $producer },
+ { key => 'primary });
+
+Find an existing record from this resultset, based on its primary
+key, or a unique constraint. If none exists, instantiate a new result
+object and return it. The object will not be saved into your storage
until you call L<DBIx::Class::Row/insert> on it.
+You most likely want this method when looking for existing rows using
+a unique constraint that is not the primary key, or looking for
+related rows.
+
If you want objects to be saved immediately, use L</find_or_create> instead.
+B<Note>: C<find_or_new> is probably not what you want when creating a
+new row in a table that uses primary keys supplied by the
+database. Passing in a primary key column with a value of I<undef>
+will cause L</find> to attempt to search for a row with a value of
+I<NULL>.
+
=cut
sub find_or_new {
=item Arguments: \%vals
-=item Return Value: $object
+=item Return Value: a L<DBIx::Class::Row> $object
=back
-Inserts a record into the resultset and returns the object representing it.
+Attempt to create a single new row or a row with multiple related rows
+in the table represented by the resultset (and related tables). This
+will not check for duplicate rows before inserting, use
+L</find_or_create> to do that.
+
+To create one row for this resultset, pass a hashref of key/value
+pairs representing the columns of the table and the values you wish to
+store. If the appropriate relationships are set up, foreign key fields
+can also be passed an object representing the foreign row, and the
+value will be set to its primary key.
+
+To create related objects, pass a hashref for the value if the related
+item is a foreign key relationship (L<DBIx::Class::Relationship/belongs_to>),
+and use the name of the relationship as the key. (NOT the name of the field,
+necessarily). For C<has_many> and C<has_one> relationships, pass an arrayref
+of hashrefs containing the data for each of the rows to create in the foreign
+tables, again using the relationship name as the key.
+
+Instead of hashrefs of plain related data (key/value pairs), you may
+also pass new or inserted objects. New objects (not inserted yet, see
+L</new>), will be inserted into their appropriate tables.
Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
+Example of creating a new row.
+
+ $person_rs->create({
+ name=>"Some Person",
+ email=>"somebody@someplace.com"
+ });
+
+Example of creating a new row and also creating rows in a related C<has_many>
+or C<has_one> resultset. Note Arrayref.
+
+ $artist_rs->create(
+ { artistid => 4, name => 'Manufactured Crap', cds => [
+ { title => 'My First CD', year => 2006 },
+ { title => 'Yet More Tweeny-Pop crap', year => 2007 },
+ ],
+ },
+ );
+
+Example of creating a new row and also creating a row in a related
+C<belongs_to>resultset. Note Hashref.
+
+ $cd_rs->create({
+ title=>"Music for Silly Walks",
+ year=>2000,
+ artist => {
+ name=>"Silly Musician",
+ }
+ });
+
=cut
sub create {
=item Arguments: \%vals, \%attrs?
-=item Return Value: $object
+=item Return Value: $rowobject
=back
- $class->find_or_create({ key => $val, ... });
+ $cd->cd_to_producer->find_or_create({ producer => $producer },
+ { key => 'primary });
-Tries to find a record based on its primary key or unique constraint; if none
+Tries to find a record based on its primary key or unique constraints; if none
is found, creates one and returns that instead.
my $cd = $schema->resultset('CD')->find_or_create({
{ key => 'cd_artist_title' }
);
+B<Note>: Because find_or_create() reads from the database and then
+possibly inserts based on the result, this method is subject to a race
+condition. Another process could create a record in the table after
+the find has completed and before the create has started. To avoid
+this problem, use find_or_create() inside a transaction.
+
+B<Note>: C<find_or_create> is probably not what you want when creating
+a new row in a table that uses primary keys supplied by the
+database. Passing in a primary key column with a value of I<undef>
+will cause L</find> to attempt to search for a row with a value of
+I<NULL>.
+
See also L</find> and L</update_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
=item Arguments: \%col_values, { key => $unique_constraint }?
-=item Return Value: $object
+=item Return Value: $rowobject
=back
- $class->update_or_create({ col => $val, ... });
+ $resultset->update_or_create({ col => $val, ... });
First, searches for an existing row matching one of the unique constraints
(including the primary key) on the source of this resultset. If a row is
{ key => 'cd_artist_title' }
);
+ $cd->cd_to_producer->update_or_create({
+ producer => $producer,
+ name => 'harry',
+ }, {
+ key => 'primary,
+ });
+
+
If no C<key> is specified, it searches on all unique constraints defined on the
source, including the primary key.
See also L</find> and L</find_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
+B<Note>: C<update_or_create> is probably not what you want when
+looking for a row in a table that uses primary keys supplied by the
+database, unless you actually have a key value. Passing in a primary
+key column with a value of I<undef> will cause L</find> to attempt to
+search for a row with a value of I<NULL>.
+
=cut
sub update_or_create {
return $self->create($cond);
}
+=head2 update_or_new
+
+=over 4
+
+=item Arguments: \%col_values, { key => $unique_constraint }?
+
+=item Return Value: $rowobject
+
+=back
+
+ $resultset->update_or_new({ col => $val, ... });
+
+First, searches for an existing row matching one of the unique constraints
+(including the primary key) on the source of this resultset. If a row is
+found, updates it with the other given column values. Otherwise, instantiate
+a new result object and return it. The object will not be saved into your storage
+until you call L<DBIx::Class::Row/insert> on it.
+
+Takes an optional C<key> attribute to search on a specific unique constraint.
+For example:
+
+ # In your application
+ my $cd = $schema->resultset('CD')->update_or_new(
+ {
+ artist => 'Massive Attack',
+ title => 'Mezzanine',
+ year => 1998,
+ },
+ { key => 'cd_artist_title' }
+ );
+
+ if ($cd->in_storage) {
+ # the cd was updated
+ }
+ else {
+ # the cd is not yet in the database, let's insert it
+ $cd->insert;
+ }
+
+See also L</find>, L</find_or_create> and L<find_or_new>.
+
+=cut
+
+sub update_or_new {
+ my $self = shift;
+ my $attrs = ( @_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {} );
+ my $cond = ref $_[0] eq 'HASH' ? shift : {@_};
+
+ my $row = $self->find( $cond, $attrs );
+ if ( defined $row ) {
+ $row->update($cond);
+ return $row;
+ }
+
+ return $self->new_result($cond);
+}
+
=head2 get_cache
=over 4
Gets the contents of the cache for the resultset, if the cache is set.
+The cache is populated either by using the L</prefetch> attribute to
+L</search> or by calling L</set_cache>.
+
=cut
sub get_cache {
if the cache is set the resultset will return the cached objects rather
than re-querying the database even if the cache attr is not set.
+The contents of the cache can also be populated by using the
+L</prefetch> attribute to L</search>.
+
=cut
sub set_cache {
my $rel_obj = $self->result_source->relationship_info($rel);
$self->throw_exception(
- "search_related: result source '" . $self->_source_handle->source_moniker .
+ "search_related: result source '" . $self->result_source->source_name .
"' has no such relationship $rel")
unless $rel_obj;
-
+
my ($from,$seen) = $self->_resolve_from($rel);
my $join_count = $seen->{$rel};
my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
- $self->_source_handle->schema->resultset($rel_obj->{class})->search_rs(
- undef, {
- %{$self->{attrs}||{}},
- join => undef,
- prefetch => undef,
- select => undef,
- as => undef,
- alias => $alias,
- where => $self->{cond},
- seen_join => $seen,
- from => $from,
- });
+ #XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
+ my %attrs = %{$self->{attrs}||{}};
+ delete @attrs{qw(result_class alias)};
+
+ my $new_cache;
+
+ if (my $cache = $self->get_cache) {
+ if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) {
+ $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} }
+ @$cache ];
+ }
+ }
+
+ my $rel_source = $self->result_source->related_source($rel);
+
+ my $new = do {
+
+ # The reason we do this now instead of passing the alias to the
+ # search_rs below is that if you wrap/overload resultset on the
+ # source you need to know what alias it's -going- to have for things
+ # to work sanely (e.g. RestrictWithObject wants to be able to add
+ # extra query restrictions, and these may need to be $alias.)
+
+ my $attrs = $rel_source->resultset_attributes;
+ local $attrs->{alias} = $alias;
+
+ $rel_source->resultset
+ ->search_rs(
+ undef, {
+ %attrs,
+ join => undef,
+ prefetch => undef,
+ select => undef,
+ as => undef,
+ where => $self->{cond},
+ seen_join => $seen,
+ from => $from,
+ });
+ };
+ $new->set_cache($new_cache) if $new_cache;
+ $new;
};
}
+=head2 current_source_alias
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $source_alias
+
+=back
+
+Returns the current table alias for the result source this resultset is built
+on, that will be used in the SQL query. Usually it is C<me>.
+
+Currently the source alias that refers to the result set returned by a
+L</search>/L</find> family method depends on how you got to the resultset: it's
+C<me> by default, but eg. L</search_related> aliases it to the related result
+source name (and keeps C<me> referring to the original result set). The long
+term goal is to make L<DBIx::Class> always alias the current resultset as C<me>
+(and make this method unnecessary).
+
+Thus it's currently necessary to use this method in predefined queries (see
+L<DBIx::Class::Manual::Cookbook/Predefined searches>) when referring to the
+source alias of the current result set:
+
+ # in a result set class
+ sub modified_by {
+ my ($self, $user) = @_;
+
+ my $me = $self->current_source_alias;
+
+ return $self->search(
+ "$me.modified" => $user->id,
+ );
+ }
+
+=cut
+
+sub current_source_alias {
+ my ($self) = @_;
+
+ return ($self->{attrs} || {})->{alias} || 'me';
+}
+
+# This code is called by search_related, and makes sure there
+# is clear separation between the joins before, during, and
+# after the relationship. This information is needed later
+# in order to properly resolve prefetch aliases (any alias
+# with a relation_chain_depth less than the depth of the
+# current prefetch is not considered)
sub _resolve_from {
my ($self, $extra_join) = @_;
my $source = $self->result_source;
my $attrs = $self->{attrs};
-
+
my $from = $attrs->{from}
|| [ { $attrs->{alias} => $source->from } ];
-
+
my $seen = { %{$attrs->{seen_join}||{}} };
- my $join = ($attrs->{join}
- ? [ $attrs->{join}, $extra_join ]
- : $extra_join);
- $from = [
- @$from,
- ($join ? $source->resolve_join($join, $attrs->{alias}, $seen) : ()),
- ];
+ # we need to take the prefetch the attrs into account before we
+ # ->_resolve_join as otherwise they get lost - captainL
+ my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
+
+ push @$from, $source->_resolve_join($merged, $attrs->{alias}, $seen) if ($merged);
+
+ ++$seen->{-relation_chain_depth};
+
+ push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
+
+ ++$seen->{-relation_chain_depth};
return ($from,$seen);
}
my $self = shift;
return $self->{_attrs} if $self->{_attrs};
- my $attrs = { %{$self->{attrs}||{}} };
+ my $attrs = { %{ $self->{attrs} || {} } };
my $source = $self->result_source;
- my $alias = $attrs->{alias};
+ my $alias = $attrs->{alias};
$attrs->{columns} ||= delete $attrs->{cols} if exists $attrs->{cols};
- if ($attrs->{columns}) {
- delete $attrs->{as};
- } elsif (!$attrs->{select}) {
- $attrs->{columns} = [ $source->columns ];
- }
-
- $attrs->{select} =
- ($attrs->{select}
- ? (ref $attrs->{select} eq 'ARRAY'
- ? [ @{$attrs->{select}} ]
- : [ $attrs->{select} ])
- : [ map { m/\./ ? $_ : "${alias}.$_" } @{delete $attrs->{columns}} ]
- );
- $attrs->{as} =
- ($attrs->{as}
- ? (ref $attrs->{as} eq 'ARRAY'
- ? [ @{$attrs->{as}} ]
- : [ $attrs->{as} ])
- : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{$attrs->{select}} ]
+ my @colbits;
+
+ # build columns (as long as select isn't set) into a set of as/select hashes
+ unless ( $attrs->{select} ) {
+ @colbits = map {
+ ( ref($_) eq 'HASH' )
+ ? $_
+ : {
+ (
+ /^\Q${alias}.\E(.+)$/
+ ? "$1"
+ : "$_"
+ )
+ =>
+ (
+ /\./
+ ? "$_"
+ : "${alias}.$_"
+ )
+ }
+ } ( ref($attrs->{columns}) eq 'ARRAY' ) ? @{ delete $attrs->{columns}} : (delete $attrs->{columns} || $source->columns );
+ }
+ # add the additional columns on
+ foreach ( 'include_columns', '+columns' ) {
+ push @colbits, map {
+ ( ref($_) eq 'HASH' )
+ ? $_
+ : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
+ } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
+ }
+
+ # start with initial select items
+ if ( $attrs->{select} ) {
+ $attrs->{select} =
+ ( ref $attrs->{select} eq 'ARRAY' )
+ ? [ @{ $attrs->{select} } ]
+ : [ $attrs->{select} ];
+ $attrs->{as} = (
+ $attrs->{as}
+ ? (
+ ref $attrs->{as} eq 'ARRAY'
+ ? [ @{ $attrs->{as} } ]
+ : [ $attrs->{as} ]
+ )
+ : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
);
-
- my $adds;
- if ($adds = delete $attrs->{include_columns}) {
- $adds = [$adds] unless ref $adds eq 'ARRAY';
- push(@{$attrs->{select}}, @$adds);
- push(@{$attrs->{as}}, map { m/([^.]+)$/; $1 } @$adds);
}
- if ($adds = delete $attrs->{'+select'}) {
+ else {
+
+ # otherwise we intialise select & as to empty
+ $attrs->{select} = [];
+ $attrs->{as} = [];
+ }
+
+ # now add colbits to select/as
+ push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
+ push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
+
+ my $adds;
+ if ( $adds = delete $attrs->{'+select'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push(@{$attrs->{select}},
- map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds);
+ push(
+ @{ $attrs->{select} },
+ map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
+ );
}
- if (my $adds = delete $attrs->{'+as'}) {
+ if ( $adds = delete $attrs->{'+as'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push(@{$attrs->{as}}, @$adds);
+ push( @{ $attrs->{as} }, @$adds );
}
- $attrs->{from} ||= [ { 'me' => $source->from } ];
+ $attrs->{from} ||= [ { $self->{attrs}{alias} => $source->from } ];
- if (exists $attrs->{join} || exists $attrs->{prefetch}) {
+ if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
my $join = delete $attrs->{join} || {};
- if (defined $attrs->{prefetch}) {
- $join = $self->_merge_attr(
- $join, $attrs->{prefetch}
- );
+ if ( defined $attrs->{prefetch} ) {
+ $join = $self->_merge_attr( $join, $attrs->{prefetch} );
+
}
- $attrs->{from} = # have to copy here to avoid corrupting the original
+ $attrs->{from} = # have to copy here to avoid corrupting the original
[
- @{$attrs->{from}},
- $source->resolve_join($join, $alias, { %{$attrs->{seen_join}||{}} })
+ @{ $attrs->{from} },
+ $source->_resolve_join(
+ $join, $alias, { %{ $attrs->{seen_join} || {} } }
+ )
];
+
}
- $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
- if ($attrs->{order_by}) {
- $attrs->{order_by} = (ref($attrs->{order_by}) eq 'ARRAY'
- ? [ @{$attrs->{order_by}} ]
- : [ $attrs->{order_by} ]);
- } else {
- $attrs->{order_by} = [];
+ $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ]
+ if delete $attrs->{distinct};
+ if ( $attrs->{order_by} ) {
+ $attrs->{order_by} = (
+ ref( $attrs->{order_by} ) eq 'ARRAY'
+ ? [ @{ $attrs->{order_by} } ]
+ : [ $attrs->{order_by} ]
+ );
+ }
+ else {
+ $attrs->{order_by} = [];
}
my $collapse = $attrs->{collapse} || {};
- if (my $prefetch = delete $attrs->{prefetch}) {
- $prefetch = $self->_merge_attr({}, $prefetch);
+ if ( my $prefetch = delete $attrs->{prefetch} ) {
+ $prefetch = $self->_merge_attr( {}, $prefetch );
my @pre_order;
- my $seen = $attrs->{seen_join} || {};
- foreach my $p (ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch)) {
+ foreach my $p ( ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch) ) {
+
# bring joins back to level of current class
- my @prefetch = $source->resolve_prefetch(
- $p, $alias, $seen, \@pre_order, $collapse
- );
- push(@{$attrs->{select}}, map { $_->[0] } @prefetch);
- push(@{$attrs->{as}}, map { $_->[1] } @prefetch);
+ my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
+ my @prefetch =
+ $source->_resolve_prefetch( $p, $alias, $join_map, \@pre_order, $collapse );
+ push( @{ $attrs->{select} }, map { $_->[0] } @prefetch );
+ push( @{ $attrs->{as} }, map { $_->[1] } @prefetch );
}
- push(@{$attrs->{order_by}}, @pre_order);
+ push( @{ $attrs->{order_by} }, @pre_order );
}
$attrs->{collapse} = $collapse;
+ if ( $attrs->{page} and not defined $attrs->{offset} ) {
+ $attrs->{offset} = ( $attrs->{rows} * ( $attrs->{page} - 1 ) );
+ }
+
return $self->{_attrs} = $attrs;
}
-sub _merge_attr {
+sub _joinpath_aliases {
+ my ($self, $fromspec, $seen) = @_;
+
+ my $paths = {};
+ return $paths unless ref $fromspec eq 'ARRAY';
+
+ for my $j (@$fromspec) {
+
+ next if ref $j ne 'ARRAY';
+ next if $j->[0]{-relation_chain_depth} < ( $seen->{-relation_chain_depth} || 0);
+
+ my $p = $paths;
+ $p = $p->{$_} ||= {} for @{$j->[0]{-join_path}};
+ push @{$p->{-join_aliases} }, $j->[0]{-join_alias};
+ }
+
+ return $paths;
+}
+
+sub _rollout_attr {
+ my ($self, $attr) = @_;
+
+ if (ref $attr eq 'HASH') {
+ return $self->_rollout_hash($attr);
+ } elsif (ref $attr eq 'ARRAY') {
+ return $self->_rollout_array($attr);
+ } else {
+ return [$attr];
+ }
+}
+
+sub _rollout_array {
+ my ($self, $attr) = @_;
+
+ my @rolled_array;
+ foreach my $element (@{$attr}) {
+ if (ref $element eq 'HASH') {
+ push( @rolled_array, @{ $self->_rollout_hash( $element ) } );
+ } elsif (ref $element eq 'ARRAY') {
+ # XXX - should probably recurse here
+ push( @rolled_array, @{$self->_rollout_array($element)} );
+ } else {
+ push( @rolled_array, $element );
+ }
+ }
+ return \@rolled_array;
+}
+
+sub _rollout_hash {
+ my ($self, $attr) = @_;
+
+ my @rolled_array;
+ foreach my $key (keys %{$attr}) {
+ push( @rolled_array, { $key => $attr->{$key} } );
+ }
+ return \@rolled_array;
+}
+
+sub _calculate_score {
my ($self, $a, $b) = @_;
- return $b unless defined($a);
- return $a unless defined($b);
-
- if (ref $b eq 'HASH' && ref $a eq 'HASH') {
- foreach my $key (keys %{$b}) {
- if (exists $a->{$key}) {
- $a->{$key} = $self->_merge_attr($a->{$key}, $b->{$key});
+
+ if (ref $b eq 'HASH') {
+ my ($b_key) = keys %{$b};
+ if (ref $a eq 'HASH') {
+ my ($a_key) = keys %{$a};
+ if ($a_key eq $b_key) {
+ return (1 + $self->_calculate_score( $a->{$a_key}, $b->{$b_key} ));
} else {
- $a->{$key} = $b->{$key};
+ return 0;
}
+ } else {
+ return ($a eq $b_key) ? 1 : 0;
}
- return $a;
} else {
- $a = [$a] unless ref $a eq 'ARRAY';
- $b = [$b] unless ref $b eq 'ARRAY';
-
- my $hash = {};
- my @array;
- foreach my $x ($a, $b) {
- foreach my $element (@{$x}) {
- if (ref $element eq 'HASH') {
- $hash = $self->_merge_attr($hash, $element);
- } elsif (ref $element eq 'ARRAY') {
- push(@array, @{$element});
- } else {
- push(@array, $element) unless $b == $x
- && grep { $_ eq $element } @array;
- }
+ if (ref $a eq 'HASH') {
+ my ($a_key) = keys %{$a};
+ return ($b eq $a_key) ? 1 : 0;
+ } else {
+ return ($b eq $a) ? 1 : 0;
+ }
+ }
+}
+
+sub _merge_attr {
+ my ($self, $orig, $import) = @_;
+
+ return $import unless defined($orig);
+ return $orig unless defined($import);
+
+ $orig = $self->_rollout_attr($orig);
+ $import = $self->_rollout_attr($import);
+
+ my $seen_keys;
+ foreach my $import_element ( @{$import} ) {
+ # find best candidate from $orig to merge $b_element into
+ my $best_candidate = { position => undef, score => 0 }; my $position = 0;
+ foreach my $orig_element ( @{$orig} ) {
+ my $score = $self->_calculate_score( $orig_element, $import_element );
+ if ($score > $best_candidate->{score}) {
+ $best_candidate->{position} = $position;
+ $best_candidate->{score} = $score;
}
+ $position++;
}
-
- @array = grep { !exists $hash->{$_} } @array;
+ my ($import_key) = ( ref $import_element eq 'HASH' ) ? keys %{$import_element} : ($import_element);
- return keys %{$hash}
- ? ( scalar(@array)
- ? [$hash, @array]
- : $hash
- )
- : \@array;
+ if ($best_candidate->{score} == 0 || exists $seen_keys->{$import_key}) {
+ push( @{$orig}, $import_element );
+ } else {
+ my $orig_best = $orig->[$best_candidate->{position}];
+ # merge orig_best and b_element together and replace original with merged
+ if (ref $orig_best ne 'HASH') {
+ $orig->[$best_candidate->{position}] = $import_element;
+ } elsif (ref $import_element eq 'HASH') {
+ my ($key) = keys %{$orig_best};
+ $orig->[$best_candidate->{position}] = { $key => $self->_merge_attr($orig_best->{$key}, $import_element->{$key}) };
+ }
+ }
+ $seen_keys->{$import_key} = 1; # don't merge the same key twice
}
+
+ return $orig;
}
sub result_source {
sub throw_exception {
my $self=shift;
- $self->_source_handle->schema->throw_exception(@_);
+ if (ref $self && $self->_source_handle->schema) {
+ $self->_source_handle->schema->throw_exception(@_)
+ } else {
+ croak(@_);
+ }
+
}
# XXX: FIXME: Attributes docs need clearing up
=head1 ATTRIBUTES
-The resultset takes various attributes that modify its behavior. Here's an
-overview of them:
+Attributes are used to refine a ResultSet in various ways when
+searching for data. They can be passed to any method which takes an
+C<\%attrs> argument. See L</search>, L</search_rs>, L</find>,
+L</count>.
+
+These are in no particular order:
=head2 order_by
=over 4
-=item Value: ($order_by | \@order_by)
+=item Value: ( $order_by | \@order_by | \%order_by )
=back
-Which column(s) to order the results by. This is currently passed
-through directly to SQL, so you can give e.g. C<year DESC> for a
-descending order on the column `year'.
+Which column(s) to order the results by. If a single column name, or
+an arrayref of names is supplied, the argument is passed through
+directly to SQL. The hashref syntax allows for connection-agnostic
+specification of ordering direction:
+
+ For descending order:
+
+ order_by => { -desc => [qw/col1 col2 col3/] }
+
+ For explicit ascending order:
+
+ order_by => { -asc => 'col' }
-Please note that if you have C<quote_char> enabled (see
-L<DBIx::Class::Storage::DBI/connect_info>) you will need to do C<\'year DESC' > to
-specify an order. (The scalar ref causes it to be passed as raw sql to the DB,
-so you will need to manually quote things as appropriate.)
+The old scalarref syntax (i.e. order_by => \'year DESC') is still
+supported, although you are strongly encouraged to use the hashref
+syntax as outlined above.
=head2 columns
=back
-Shortcut to request a particular set of columns to be retrieved. Adds
-C<me.> onto the start of any column without a C<.> in it and sets C<select>
-from that, then auto-populates C<as> from C<select> as normal. (You may also
-use the C<cols> attribute, as in earlier versions of DBIC.)
+Shortcut to request a particular set of columns to be retrieved. Each
+column spec may be a string (a table column name), or a hash (in which
+case the key is the C<as> value, and the value is used as the C<select>
+expression). Adds C<me.> onto the start of any column without a C<.> in
+it and sets C<select> from that, then auto-populates C<as> from
+C<select> as normal. (You may also use the C<cols> attribute, as in
+earlier versions of DBIC.)
-=head2 include_columns
+=head2 +columns
=over 4
=back
-Shortcut to include additional columns in the returned results - for example
+Indicates additional columns to be selected from storage. Works the same
+as L</columns> but adds columns to the selection. (You may also use the
+C<include_columns> attribute, as in earlier versions of DBIC). For
+example:-
$schema->resultset('CD')->search(undef, {
- include_columns => ['artist.name'],
+ '+columns' => ['artist.name'],
join => ['artist']
});
would return all CDs and include a 'name' column to the information
-passed to object inflation
+passed to object inflation. Note that the 'artist' is the name of the
+column (or relationship) accessor, and 'name' is the name of the column
+accessor in the related table.
+
+=head2 include_columns
+
+=over 4
+
+=item Value: \@columns
+
+=back
+
+Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
=head2 select
=over 4
Indicates additional columns to be selected from storage. Works the same as
-L<select> but adds columns to the selection.
+L</select> but adds columns to the selection.
=back
=over 4
-Indicates additional column names for those added via L<+select>.
+Indicates additional column names for those added via L</+select>. See L</as>.
=back
=back
-Indicates column names for object inflation. This is used in conjunction with
-C<select>, usually when C<select> contains one or more function or stored
+Indicates column names for object inflation. That is, C<as>
+indicates the name that the column can be accessed as via the
+C<get_column> method (or via the object accessor, B<if one already
+exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
+
+The C<as> attribute is used in conjunction with C<select>,
+usually when C<select> contains one or more function or stored
procedure names:
$rs = $schema->resultset('Employee')->search(undef, {
}
);
-You need to use the relationship (not the table) name in conditions,
-because they are aliased as such. The current table is aliased as "me", so
+You need to use the relationship (not the table) name in conditions,
+because they are aliased as such. The current table is aliased as "me", so
you need to use me.column_name in order to avoid ambiguity. For example:
- # Get CDs from 1984 with a 'Foo' track
+ # Get CDs from 1984 with a 'Foo' track
my $rs = $schema->resultset('CD')->search(
- {
+ {
'me.year' => 1984,
'tracks.name' => 'Foo'
},
{ join => 'tracks' }
);
-
+
If the same join is supplied twice, it will be aliased to <rel>_2 (and
similarly for a third time). For e.g.
If you want to fetch related objects from other tables as well, see C<prefetch>
below.
+For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
+
=head2 prefetch
=over 4
=back
-Contains one or more relationships that should be fetched along with the main
-query (when they are accessed afterwards they will have already been
-"prefetched"). This is useful for when you know you will need the related
-objects, because it saves at least one query:
+Contains one or more relationships that should be fetched along with
+the main query (when they are accessed afterwards the data will
+already be available, without extra queries to the database). This is
+useful for when you know you will need the related objects, because it
+saves at least one query:
my $rs = $schema->resultset('Tag')->search(
undef,
case.
Simple prefetches will be joined automatically, so there is no need
-for a C<join> attribute in the above search. If you're prefetching to
-depth (e.g. { cd => { artist => 'label' } or similar), you'll need to
-specify the join as well.
+for a C<join> attribute in the above search.
C<prefetch> can be used with the following relationship types: C<belongs_to>,
C<has_one> (or if you're using C<add_relationship>, any relationship declared
-with an accessor type of 'single' or 'filter').
+with an accessor type of 'single' or 'filter'). A more complex example that
+prefetches an artists cds, the tracks on those cds, and the tags associted
+with that artist is given below (assuming many-to-many from artists to tags):
+
+ my $rs = $schema->resultset('Artist')->search(
+ undef,
+ {
+ prefetch => [
+ { cds => 'tracks' },
+ { artist_tags => 'tags' }
+ ]
+ }
+ );
+
+
+B<NOTE:> If you specify a C<prefetch> attribute, the C<join> and C<select>
+attributes will be ignored.
=head2 page
If L<rows> attribute is not specified it defualts to 10 rows per page.
+When you have a paged resultset, L</count> will only return the number
+of rows in the page. To get the total, use the L</pager> and call
+C<total_entries> on it.
+
=head2 rows
=over 4
# SELECT child.* FROM person child
# INNER JOIN person father ON child.father_id = father.id
+If you need to express really complex joins or you need a subselect, you
+can supply literal SQL to C<from> via a scalar reference. In this case
+the contents of the scalar will replace the table name asscoiated with the
+resultsource.
+
+WARNING: This technique might very well not work as expected on chained
+searches - you have been warned.
+
+ # Assuming the Event resultsource is defined as:
+
+ MySchema::Event->add_columns (
+ sequence => {
+ data_type => 'INT',
+ is_auto_increment => 1,
+ },
+ location => {
+ data_type => 'INT',
+ },
+ type => {
+ data_type => 'INT',
+ },
+ );
+ MySchema::Event->set_primary_key ('sequence');
+
+ # This will get back the latest event for every location. The column
+ # selector is still provided by DBIC, all we do is add a JOIN/WHERE
+ # combo to limit the resultset
+
+ $rs = $schema->resultset('Event');
+ $table = $rs->result_source->name;
+ $latest = $rs->search (
+ undef,
+ { from => \ "
+ (SELECT e1.* FROM $table e1
+ JOIN $table e2
+ ON e1.location = e2.location
+ AND e1.sequence < e2.sequence
+ WHERE e2.sequence is NULL
+ ) me",
+ },
+ );
+
+ # Equivalent SQL (with the DBIC chunks added):
+
+ SELECT me.sequence, me.location, me.type FROM
+ (SELECT e1.* FROM events e1
+ JOIN events e2
+ ON e1.location = e2.location
+ AND e1.sequence < e2.sequence
+ WHERE e2.sequence is NULL
+ ) me;
+
+=head2 for
+
+=over 4
+
+=item Value: ( 'update' | 'shared' )
+
+=back
+
+Set to 'update' for a SELECT ... FOR UPDATE or 'shared' for a SELECT
+... FOR SHARED.
+
=cut
1;
projects / dbsrgits/DBIx-Class.git / blobdiff