use strict;
use warnings;
use overload
- '0+' => 'count',
+ '0+' => \&count,
+ 'bool' => sub { 1; },
fallback => 1;
use Data::Page;
+use Storable;
+use Scalar::Util qw/weaken/;
+
+use base qw/DBIx::Class/;
+__PACKAGE__->load_components(qw/AccessorGroup/);
+__PACKAGE__->mk_group_accessors('simple' => qw/result_source result_class/);
=head1 NAME
=head1 SYNOPSIS
-my $rs = MyApp::DB::Class->search(registered => 1);
-my @rows = MyApp::DB::Class->search(foo => 'bar');
+ my $rs = $schema->resultset('User')->search(registered => 1);
+ my @rows = $schema->resultset('CD')->search(year => 2005);
=head1 DESCRIPTION
The resultset is also known as an iterator. It is responsible for handling
-queries that may return an arbitrary number of rows, e.g. via C<search>
+queries that may return an arbitrary number of rows, e.g. via L</search>
or a C<has_many> relationship.
+In the examples below, the following table classes are used:
+
+ package MyApp::Schema::Artist;
+ use base qw/DBIx::Class/;
+ __PACKAGE__->load_components(qw/Core/);
+ __PACKAGE__->table('artist');
+ __PACKAGE__->add_columns(qw/artistid name/);
+ __PACKAGE__->set_primary_key('artistid');
+ __PACKAGE__->has_many(cds => 'MyApp::Schema::CD');
+ 1;
+
+ package MyApp::Schema::CD;
+ use base qw/DBIx::Class/;
+ __PACKAGE__->load_components(qw/Core/);
+ __PACKAGE__->table('cd');
+ __PACKAGE__->add_columns(qw/cdid artist title year/);
+ __PACKAGE__->set_primary_key('cdid');
+ __PACKAGE__->belongs_to(artist => 'MyApp::Schema::Artist');
+ 1;
+
=head1 METHODS
-=head2 new($source, \%$attrs)
+=head2 new
+
+=over 4
+
+=item Arguments: $source, \%$attrs
+
+=item Return Value: $rs
+
+=back
+
+The resultset constructor. Takes a source object (usually a
+L<DBIx::Class::ResultSourceProxy::Table>) and an attribute hash (see
+L</ATTRIBUTES> below). Does not perform any queries -- these are
+executed as needed by the other methods.
-The resultset constructor. Takes a source object (usually a DBIx::Class::Table)
-and an attribute hash (see below for more information on attributes). Does
-not perform any queries -- these are executed as needed by the other methods.
+Generally you won't need to construct a resultset manually. You'll
+automatically get one from e.g. a L</search> called in scalar context:
+
+ my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
+
+IMPORTANT: If called on an object, proxies to new_result instead so
+
+ my $cd = $schema->resultset('CD')->new({ title => 'Spoon' });
+
+will return a CD object, not a ResultSet.
=cut
sub new {
- my ($class, $source, $attrs) = @_;
- #use Data::Dumper; warn Dumper(@_);
- $class = ref $class if ref $class;
- $attrs = { %{ $attrs || {} } };
- my %seen;
+ my $class = shift;
+ return $class->new_result(@_) if ref $class;
+
+ my ($source, $attrs) = @_;
+ weaken $source;
+ $attrs = Storable::dclone($attrs || {}); # { %{ $attrs || {} } };
+ #use Data::Dumper; warn Dumper($attrs);
my $alias = ($attrs->{alias} ||= 'me');
- if (!$attrs->{select}) {
- my @cols = ($attrs->{cols}
- ? @{delete $attrs->{cols}}
- : $source->result_class->_select_columns);
- $attrs->{select} = [ map { m/\./ ? $_ : "${alias}.$_" } @cols ];
+
+ $attrs->{columns} ||= delete $attrs->{cols} if $attrs->{cols};
+ delete $attrs->{as} if $attrs->{columns};
+ $attrs->{columns} ||= [ $source->columns ] unless $attrs->{select};
+ $attrs->{select} = [
+ map { m/\./ ? $_ : "${alias}.$_" } @{delete $attrs->{columns}}
+ ] if $attrs->{columns};
+ $attrs->{as} ||= [
+ map { m/^\Q$alias.\E(.+)$/ ? $1 : $_ } @{$attrs->{select}}
+ ];
+ if (my $include = delete $attrs->{include_columns}) {
+ push(@{$attrs->{select}}, @$include);
+ push(@{$attrs->{as}}, map { m/([^.]+)$/; $1; } @$include);
}
- $attrs->{as} ||= [ map { m/^$alias\.(.*)$/ ? $1 : $_ } @{$attrs->{select}} ];
#use Data::Dumper; warn Dumper(@{$attrs}{qw/select as/});
- $attrs->{from} ||= [ { $alias => $source->name } ];
+
+ $attrs->{from} ||= [ { $alias => $source->from } ];
+ $attrs->{seen_join} ||= {};
+ my %seen;
if (my $join = delete $attrs->{join}) {
- foreach my $j (ref $join eq 'ARRAY'
- ? (@{$join}) : ($join)) {
+ foreach my $j (ref $join eq 'ARRAY' ? @$join : ($join)) {
if (ref $j eq 'HASH') {
$seen{$_} = 1 foreach keys %$j;
} else {
$seen{$j} = 1;
}
}
- push(@{$attrs->{from}}, $source->result_class->_resolve_join($join, $attrs->{alias}));
+ push(@{$attrs->{from}}, $source->resolve_join(
+ $join, $attrs->{alias}, $attrs->{seen_join})
+ );
}
+
$attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
- foreach my $pre (@{delete $attrs->{prefetch} || []}) {
- push(@{$attrs->{from}}, $source->result_class->_resolve_join($pre, $attrs->{alias}))
- unless $seen{$pre};
- my @pre =
- map { "$pre.$_" }
- $source->result_class->_relationships->{$pre}->{class}->columns;
- push(@{$attrs->{select}}, @pre);
- push(@{$attrs->{as}}, @pre);
+ $attrs->{order_by} = [ $attrs->{order_by} ] if
+ $attrs->{order_by} and !ref($attrs->{order_by});
+ $attrs->{order_by} ||= [];
+
+ my $collapse = $attrs->{collapse} || {};
+ if (my $prefetch = delete $attrs->{prefetch}) {
+ my @pre_order;
+ foreach my $p (ref $prefetch eq 'ARRAY' ? @$prefetch : ($prefetch)) {
+ if ( ref $p eq 'HASH' ) {
+ foreach my $key (keys %$p) {
+ push(@{$attrs->{from}}, $source->resolve_join($p, $attrs->{alias}))
+ unless $seen{$key};
+ }
+ } else {
+ push(@{$attrs->{from}}, $source->resolve_join($p, $attrs->{alias}))
+ unless $seen{$p};
+ }
+ my @prefetch = $source->resolve_prefetch(
+ $p, $attrs->{alias}, {}, \@pre_order, $collapse);
+ push(@{$attrs->{select}}, map { $_->[0] } @prefetch);
+ push(@{$attrs->{as}}, map { $_->[1] } @prefetch);
+ }
+ push(@{$attrs->{order_by}}, @pre_order);
}
+ $attrs->{collapse} = $collapse;
+# use Data::Dumper; warn Dumper($collapse) if keys %{$collapse};
+
if ($attrs->{page}) {
$attrs->{rows} ||= 10;
$attrs->{offset} ||= 0;
$attrs->{offset} += ($attrs->{rows} * ($attrs->{page} - 1));
}
- my $new = {
- source => $source,
+
+ bless {
+ result_source => $source,
+ result_class => $attrs->{result_class} || $source->result_class,
cond => $attrs->{where},
from => $attrs->{from},
+ collapse => $collapse,
count => undef,
page => delete $attrs->{page},
pager => undef,
- attrs => $attrs };
- bless ($new, $class);
- return $new;
+ attrs => $attrs
+ }, $class;
}
=head2 search
- my @obj = $rs->search({ foo => 3 }); # "... WHERE foo = 3"
- my $new_rs = $rs->search({ foo => 3 });
-
+=over 4
+
+=item Arguments: $cond, \%attrs?
+
+=item Return Value: $resultset (scalar context), @row_objs (list context)
+
+=back
+
+ my @cds = $cd_rs->search({ year => 2001 }); # "... WHERE year = 2001"
+ my $new_rs = $cd_rs->search({ year => 2005 });
+
+ my $new_rs = $cd_rs->search([ { year => 2005 }, { year => 2004 } ]);
+ # year = 2005 OR year = 2004
+
If you need to pass in additional attributes but no additional condition,
-call it as ->search(undef, \%attrs);
-
- my @all = $class->search({}, { cols => [qw/foo bar/] }); # "SELECT foo, bar FROM $class_table"
+call it as C<search(undef, \%attrs)>.
+
+ # "SELECT name, artistid FROM $artist_table"
+ my @all_artists = $schema->resultset('Artist')->search(undef, {
+ columns => [qw/name artistid/],
+ });
=cut
sub search {
my $self = shift;
-
- #use Data::Dumper;warn Dumper(@_);
-
+
my $attrs = { %{$self->{attrs}} };
- if (@_ > 1 && ref $_[$#_] eq 'HASH') {
- $attrs = { %$attrs, %{ pop(@_) } };
+ my $having = delete $attrs->{having};
+ $attrs = { %$attrs, %{ pop(@_) } } if @_ > 1 and ref $_[$#_] eq 'HASH';
+
+ my $where = (@_
+ ? ((@_ == 1 || ref $_[0] eq "HASH")
+ ? shift
+ : ((@_ % 2)
+ ? $self->throw_exception(
+ "Odd number of arguments to search")
+ : {@_}))
+ : undef());
+ if (defined $where) {
+ $attrs->{where} = (defined $attrs->{where}
+ ? { '-and' =>
+ [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
+ $where, $attrs->{where} ] }
+ : $where);
}
- my $where = (@_ ? ((@_ == 1 || ref $_[0] eq "HASH") ? shift : {@_}) : undef());
- if (defined $where) {
- $where = (defined $attrs->{where}
- ? { '-and' => [ $where, $attrs->{where} ] }
- : $where);
- $attrs->{where} = $where;
+ if (defined $having) {
+ $attrs->{having} = (defined $attrs->{having}
+ ? { '-and' =>
+ [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
+ $having, $attrs->{having} ] }
+ : $having);
}
- my $rs = $self->new($self->{source}, $attrs);
+ my $rs = (ref $self)->new($self->result_source, $attrs);
+ unless (@_) { # no search, effectively just a clone
+ my $rows = $self->get_cache;
+ if ($rows) {
+ $rs->set_cache($rows);
+ }
+ }
+
return (wantarray ? $rs->all : $rs);
}
-=head2 search_literal
- my @obj = $rs->search_literal($literal_where_cond, @bind);
- my $new_rs = $rs->search_literal($literal_where_cond, @bind);
+=head2 search_literal
+
+=over 4
+
+=item Arguments: $sql_fragment, @bind_values
+
+=item Return Value: $resultset (scalar context), @row_objs (list context)
+
+=back
+
+ my @cds = $cd_rs->search_literal('year = ? AND title = ?', qw/2001 Reload/);
+ my $newrs = $artist_rs->search_literal('name = ?', 'Metallica');
Pass a literal chunk of SQL to be added to the conditional part of the
-resultset
+resultset query.
=cut
-
+
sub search_literal {
my ($self, $cond, @vals) = @_;
my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
return $self->search(\$cond, $attrs);
}
-=head2 find(@colvalues), find(\%cols)
+=head2 find
+
+=over 4
-Finds a row based on its primary key(s).
+=item Arguments: @values | \%cols, \%attrs?
-=cut
+=item Return Value: $row_object
+
+=back
+
+Finds a row based on its primary key or unique constraint. For example:
+
+ my $cd = $schema->resultset('CD')->find(5);
+
+Also takes an optional C<key> attribute, to search by a specific key or unique
+constraint. For example:
+
+ my $cd = $schema->resultset('CD')->find(
+ {
+ artist => 'Massive Attack',
+ title => 'Mezzanine',
+ },
+ { key => 'artist_title' }
+ );
+
+See also L</find_or_create> and L</update_or_create>.
+
+=cut
sub find {
my ($self, @vals) = @_;
my $attrs = (@vals > 1 && ref $vals[$#vals] eq 'HASH' ? pop(@vals) : {});
- my @pk = $self->{source}->primary_columns;
- #use Data::Dumper; warn Dumper($attrs, @vals, @pk);
- $self->{source}->result_class->throw( "Can't find unless primary columns are defined" )
- unless @pk;
+
+ my @cols = $self->result_source->primary_columns;
+ if (exists $attrs->{key}) {
+ my %uniq = $self->result_source->unique_constraints;
+ $self->throw_exception(
+ "Unknown key $attrs->{key} on '" . $self->result_source->name . "'"
+ ) unless exists $uniq{$attrs->{key}};
+ @cols = @{ $uniq{$attrs->{key}} };
+ }
+ #use Data::Dumper; warn Dumper($attrs, @vals, @cols);
+ $self->throw_exception(
+ "Can't find unless a primary key or unique constraint is defined"
+ ) unless @cols;
+
my $query;
if (ref $vals[0] eq 'HASH') {
- $query = $vals[0];
- } elsif (@pk == @vals) {
+ $query = { %{$vals[0]} };
+ } elsif (@cols == @vals) {
$query = {};
- @{$query}{@pk} = @vals;
+ @{$query}{@cols} = @vals;
} else {
$query = {@vals};
}
+ foreach my $key (grep { ! m/\./ } keys %$query) {
+ $query->{"$self->{attrs}{alias}.$key"} = delete $query->{$key};
+ }
#warn Dumper($query);
- # Useless -> disabled
- #$self->{source}->result_class->throw( "Can't find unless all primary keys are specified" )
- # unless (keys %$query >= @pk); # If we check 'em we run afoul of uc/lc
- # column names etc. Not sure what to do yet
- return $self->search($query)->next;
+
+ if (keys %$attrs) {
+ my $rs = $self->search($query,$attrs);
+ return keys %{$rs->{collapse}} ? $rs->next : $rs->single;
+ } else {
+ return keys %{$self->{collapse}} ?
+ $self->search($query)->next :
+ $self->single($query);
+ }
}
=head2 search_related
- $rs->search_related('relname', $cond?, $attrs?);
+=over 4
+
+=item Arguments: $cond, \%attrs?
+
+=item Return Value: $new_resultset
+
+=back
+
+ $new_rs = $cd_rs->search_related('artist', {
+ name => 'Emo-R-Us',
+ });
+
+Searches the specified relationship, optionally specifying a condition and
+attributes for matching records. See L</ATTRIBUTES> for more information.
=cut
sub search_related {
- my ($self, $rel, @rest) = @_;
- my $rel_obj = $self->{source}->result_class->_relationships->{$rel};
- $self->{source}->result_class->throw(
- "No such relationship ${rel} in search_related")
- unless $rel_obj;
- my $r_class = $self->{source}->result_class->resolve_class($rel_obj->{class});
- my $source = $r_class->result_source;
- $source = bless({ %{$source} }, ref $source || $source);
- $source->storage($self->{source}->storage);
- $source->result_class($r_class);
- my $rs = $self->search(undef, { join => $rel });
- #use Data::Dumper; warn Dumper($rs);
- return $source->resultset_class->new(
- $source, { %{$rs->{attrs}},
- alias => $rel,
- select => undef(),
- as => undef() }
- )->search(@rest);
+ return shift->related_resultset(shift)->search(@_);
}
=head2 cursor
-Returns a storage-driven cursor to the given resultset.
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $cursor
+
+=back
+
+Returns a storage-driven cursor to the given resultset. See
+L<DBIx::Class::Cursor> for more information.
=cut
sub cursor {
my ($self) = @_;
- my ($source, $attrs) = @{$self}{qw/source attrs/};
- $attrs = { %$attrs };
+ my $attrs = { %{$self->{attrs}} };
return $self->{cursor}
- ||= $source->storage->select($self->{from}, $attrs->{select},
+ ||= $self->result_source->storage->select($self->{from}, $attrs->{select},
$attrs->{where},$attrs);
}
-=head2 search_like
-
-Identical to search except defaults to 'LIKE' instead of '=' in condition
-
-=cut
+=head2 single
-sub search_like {
- my $class = shift;
- my $attrs = { };
- if (@_ > 1 && ref $_[$#_] eq 'HASH') {
- $attrs = pop(@_);
+=over 4
+
+=item Arguments: $cond?
+
+=item Return Value: $row_object?
+
+=back
+
+ my $cd = $schema->resultset('CD')->single({ year => 2001 });
+
+Inflates the first result without creating a cursor if the resultset has
+any records in it; if not returns nothing. Used by find() as an optimisation.
+
+=cut
+
+sub single {
+ my ($self, $where) = @_;
+ my $attrs = { %{$self->{attrs}} };
+ if ($where) {
+ if (defined $attrs->{where}) {
+ $attrs->{where} = {
+ '-and' =>
+ [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
+ $where, delete $attrs->{where} ]
+ };
+ } else {
+ $attrs->{where} = $where;
+ }
}
- my $query = ref $_[0] eq "HASH" ? { %{shift()} }: {@_};
+ my @data = $self->result_source->storage->select_single(
+ $self->{from}, $attrs->{select},
+ $attrs->{where},$attrs);
+ return (@data ? $self->_construct_object(@data) : ());
+}
+
+
+=head2 search_like
+
+=over 4
+
+=item Arguments: $cond, \%attrs?
+
+=item Return Value: $resultset (scalar context), @row_objs (list context)
+
+=back
+
+ # WHERE title LIKE '%blue%'
+ $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.
+
+For more information, see L<DBIx::Class::Manual::Cookbook>.
+
+=cut
+
+sub search_like {
+ my $class = shift;
+ my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
+ my $query = ref $_[0] eq 'HASH' ? { %{shift()} }: {@_};
$query->{$_} = { 'like' => $query->{$_} } for keys %$query;
return $class->search($query, { %$attrs });
}
-=head2 slice($first, $last)
+=head2 slice
+
+=over 4
+
+=item Arguments: $first, $last
-Returns a subset of elements from the resultset.
+=item Return Value: $resultset (scalar context), @row_objs (list context)
+
+=back
+
+Returns a resultset or object list representing a subset of elements from the
+resultset slice is called on. Indexes are from 0, i.e., to get the first
+three records, call:
+
+ my ($one, $two, $three) = $rs->slice(0, 2);
=cut
sub slice {
my ($self, $min, $max) = @_;
- my $attrs = { %{ $self->{attrs} || {} } };
- $attrs->{offset} ||= 0;
+ my $attrs = {}; # = { %{ $self->{attrs} || {} } };
+ $attrs->{offset} = $self->{attrs}{offset} || 0;
$attrs->{offset} += $min;
$attrs->{rows} = ($max ? ($max - $min + 1) : 1);
- my $slice = $self->new($self->{source}, $attrs);
- return (wantarray ? $slice->all : $slice);
+ return $self->search(undef(), $attrs);
+ #my $slice = (ref $self)->new($self->result_source, $attrs);
+ #return (wantarray ? $slice->all : $slice);
}
-=head2 next
+=head2 next
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $result?
+
+=back
-Returns the next element in the resultset (undef is there is none).
+Returns the next element in the resultset (C<undef> is there is none).
+
+Can be used to efficiently iterate over records in the resultset:
+
+ my $rs = $schema->resultset('CD')->search;
+ while (my $cd = $rs->next) {
+ print $cd->title;
+ }
+
+Note that you need to store the resultset object, and call C<next> on it.
+Calling C<< resultset('Table')->next >> repeatedly will always return the
+first record from the resultset.
=cut
sub next {
my ($self) = @_;
- my @row = $self->cursor->next;
+ if (my $cache = $self->get_cache) {
+ $self->{all_cache_position} ||= 0;
+ return $cache->[$self->{all_cache_position}++];
+ }
+ if ($self->{attrs}{cache}) {
+ $self->{all_cache_position} = 1;
+ return ($self->all)[0];
+ }
+ my @row = (exists $self->{stashed_row} ?
+ @{delete $self->{stashed_row}} :
+ $self->cursor->next
+ );
+# warn Dumper(\@row); use Data::Dumper;
return unless (@row);
return $self->_construct_object(@row);
}
sub _construct_object {
my ($self, @row) = @_;
- my @cols = @{ $self->{attrs}{as} };
- #warn "@cols -> @row";
- my (%me, %pre);
- foreach my $col (@cols) {
- if ($col =~ /([^\.]+)\.([^\.]+)/) {
- $pre{$1}[0]{$2} = shift @row;
- } else {
- $me{$col} = shift @row;
- }
- }
- my $new = $self->{source}->result_class->inflate_result(\%me, \%pre);
+ my @as = @{ $self->{attrs}{as} };
+
+ my $info = $self->_collapse_result(\@as, \@row);
+
+ 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, $prefix) = @_;
+
+ my %const;
+
+ my @copy = @$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 $info = [ {}, {} ];
+ foreach my $key (keys %const) {
+ if (length $key) {
+ my $target = $info;
+ my @parts = split(/\./, $key);
+ foreach my $p (@parts) {
+ $target = $target->[1]->{$p} ||= [];
+ }
+ $target->[0] = $const{$key};
+ } else {
+ $info->[0] = $const{$key};
+ }
+ }
+
+ my @collapse;
+ if (defined $prefix) {
+ @collapse = map {
+ m/^\Q${prefix}.\E(.+)$/ ? ($1) : ()
+ } keys %{$self->{collapse}}
+ } else {
+ @collapse = keys %{$self->{collapse}};
+ };
+
+ if (@collapse) {
+ my ($c) = sort { length $a <=> length $b } @collapse;
+ my $target = $info;
+ foreach my $p (split(/\./, $c)) {
+ $target = $target->[1]->{$p} ||= [];
+ }
+ my $c_prefix = (defined($prefix) ? "${prefix}.${c}" : $c);
+ my @co_key = @{$self->{collapse}{$c_prefix}};
+ my %co_check = map { ($_, $target->[0]->{$_}); } @co_key;
+ my $tree = $self->_collapse_result($as, $row, $c_prefix);
+ my (@final, @raw);
+ while ( !(grep {
+ !defined($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, $c_prefix);
+ }
+ @$target = (@final ? @final : [ {}, {} ]);
+ # single empty result to indicate an empty prefetched has_many
+ }
+
+ return $info;
+}
+
+=head2 result_source
+
+=over 4
+
+=item Arguments: $result_source?
+
+=item Return Value: $result_source
+
+=back
+
+An accessor for the primary ResultSource object from which this ResultSet
+is derived.
+
+=cut
+
+
=head2 count
+=over 4
+
+=item Arguments: $cond, \%attrs??
+
+=item Return Value: $count
+
+=back
+
Performs an SQL C<COUNT> with the same query as the resultset was built
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 @_ && defined $_[0];
- die "Unable to ->count with a GROUP BY" if defined $self->{attrs}{group_by};
- unless (defined $self->{count}) {
- my $attrs = { %{ $self->{attrs} },
- select => { 'count' => '*' },
- as => [ 'count' ] };
- # offset, order by and page are not needed to count
- delete $attrs->{$_} for qw/rows offset order_by page pager/;
-
- ($self->{count}) = $self->new($self->{source}, $attrs)->cursor->next;
- }
- return 0 unless $self->{count};
- my $count = $self->{count};
+ 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} && $self->{attrs}{rows} < $count);
+ $self->{attrs}{rows} and $self->{attrs}{rows} < $count;
+ return $count;
+}
+
+sub _count { # Separated out so pager can get the full count
+ my $self = shift;
+ my $select = { count => '*' };
+ my $attrs = { %{ $self->{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) {
+ foreach my $column (@distinct) {
+ if ($column =~ qr/^(?:\Q$attrs->{alias}.\E)?$pk[0]$/) {
+ @distinct = ($column);
+ last;
+ }
+ }
+ }
+
+ $select = { count => { distinct => \@distinct } };
+ #use Data::Dumper; die Dumper $select;
+ }
+
+ $attrs->{select} = $select;
+ $attrs->{as} = [qw/count/];
+
+ # 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/;
+
+ my ($count) = (ref $self)->new($self->result_source, $attrs)->cursor->next;
return $count;
}
=head2 count_literal
-Calls search_literal with the passed arguments, then count.
+=over 4
+
+=item Arguments: $sql_fragment, @bind_values
+
+=item Return Value: $count
+
+=back
+
+Counts the results in a literal query. Equivalent to calling L</search_literal>
+with the passed arguments, then L</count>.
=cut
=head2 all
-Returns all elements in the resultset. Called implictly if the resultset
+=over 4
+
+=item Arguments: none
+
+=item Return Value: @objects
+
+=back
+
+Returns all elements in the resultset. Called implicitly if the resultset
is returned in list context.
=cut
sub all {
my ($self) = @_;
- return map { $self->_construct_object(@$_); }
- $self->cursor->all;
+ return @{ $self->get_cache } if $self->get_cache;
+
+ my @obj;
+
+ if (keys %{$self->{collapse}}) {
+ # Using $self->cursor->all is really just an optimisation.
+ # If we're collapsing has_many prefetches it probably makes
+ # very little difference, and this is cleaner than hacking
+ # _construct_object to survive the approach
+ $self->cursor->reset;
+ my @row = $self->cursor->next;
+ while (@row) {
+ push(@obj, $self->_construct_object(@row));
+ @row = (exists $self->{stashed_row}
+ ? @{delete $self->{stashed_row}}
+ : $self->cursor->next);
+ }
+ } else {
+ @obj = map { $self->_construct_object(@$_) } $self->cursor->all;
+ }
+
+ $self->set_cache(\@obj) if $self->{attrs}{cache};
+ return @obj;
}
=head2 reset
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $self
+
+=back
+
Resets the resultset's cursor, so you can iterate through the elements again.
=cut
sub reset {
my ($self) = @_;
+ $self->{all_cache_position} = 0;
$self->cursor->reset;
return $self;
}
=head2 first
-Resets the resultset and returns the first element.
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $object?
+
+=back
+
+Resets the resultset and returns an object for the first result (if the
+resultset returns anything).
=cut
return $_[0]->reset->next;
}
+# _cond_for_update_delete
+#
+# update/delete require the condition to be modified to handle
+# the differing SQL syntax available. This transforms the $self->{cond}
+# appropriately, returning the new condition.
+
+sub _cond_for_update_delete {
+ my ($self) = @_;
+ my $cond = {};
+
+ if (!ref($self->{cond})) {
+ # No-op. No condition, we're updating/deleting everything
+ }
+ elsif (ref $self->{cond} eq 'ARRAY') {
+ $cond = [
+ map {
+ my %hash;
+ foreach my $key (keys %{$_}) {
+ $key =~ /([^.]+)$/;
+ $hash{$1} = $_->{$key};
+ }
+ \%hash;
+ } @{$self->{cond}}
+ ];
+ }
+ elsif (ref $self->{cond} eq 'HASH') {
+ if ((keys %{$self->{cond}})[0] eq '-and') {
+ $cond->{-and} = [];
+
+ my @cond = @{$self->{cond}{-and}};
+ for (my $i = 0; $i < @cond - 1; $i++) {
+ my $entry = $cond[$i];
+
+ my %hash;
+ if (ref $entry eq 'HASH') {
+ foreach my $key (keys %{$entry}) {
+ $key =~ /([^.]+)$/;
+ $hash{$1} = $entry->{$key};
+ }
+ }
+ else {
+ $entry =~ /([^.]+)$/;
+ $hash{$entry} = $cond[++$i];
+ }
+
+ push @{$cond->{-and}}, \%hash;
+ }
+ }
+ else {
+ foreach my $key (keys %{$self->{cond}}) {
+ $key =~ /([^.]+)$/;
+ $cond->{$1} = $self->{cond}{$key};
+ }
+ }
+ }
+ else {
+ $self->throw_exception(
+ "Can't update/delete on resultset with condition unless hash or array"
+ );
+ }
+
+ return $cond;
+}
+
+
+=head2 update
+
+=over 4
+
+=item Arguments: \%values
+
+=item Return Value: $storage_rv
+
+=back
+
+Sets the specified columns in the resultset to the supplied values in a
+single query. Return value will be true if the update succeeded or false
+if no records were updated; exact type of success value is storage-dependent.
+
+=cut
+
+sub update {
+ my ($self, $values) = @_;
+ $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->from, $values, $cond
+ );
+}
+
+=head2 update_all
+
+=over 4
+
+=item Arguments: \%values
+
+=item Return Value: 1
+
+=back
+
+Fetches all objects and updates them one at a time. Note that C<update_all>
+will run DBIC cascade triggers, while L</update> will not.
+
+=cut
+
+sub update_all {
+ my ($self, $values) = @_;
+ $self->throw_exception("Values for update must be a hash")
+ unless ref $values eq 'HASH';
+ foreach my $obj ($self->all) {
+ $obj->set_columns($values)->update;
+ }
+ return 1;
+}
+
=head2 delete
-Deletes all elements in the resultset.
+=over 4
+
+=item Arguments: none
+
+=item Return Value: 1
+
+=back
+
+Deletes the contents of the resultset from its result source. Note that this
+will not run DBIC cascade triggers. See L</delete_all> if you need triggers
+to run.
=cut
sub delete {
my ($self) = @_;
- $_->delete for $self->all;
+ my $del = {};
+
+ my $cond = $self->_cond_for_update_delete;
+
+ $self->result_source->storage->delete($self->result_source->from, $cond);
return 1;
}
-*delete_all = \&delete; # Yeah, yeah, yeah ...
+=head2 delete_all
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: 1
+
+=back
+
+Fetches all objects and deletes them one at a time. Note that C<delete_all>
+will run DBIC cascade triggers, while L</delete> will not.
+
+=cut
+
+sub delete_all {
+ my ($self) = @_;
+ $_->delete for $self->all;
+ return 1;
+}
=head2 pager
-Returns a L<Data::Page> object for the current resultset. Only makes
-sense for queries with page turned on.
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $pager
+
+=back
+
+Return Value a L<Data::Page> object for the current resultset. Only makes
+sense for queries with a C<page> attribute.
=cut
sub pager {
my ($self) = @_;
my $attrs = $self->{attrs};
- die "Can't create pager for non-paged rs" unless $self->{page};
+ $self->throw_exception("Can't create pager for non-paged rs")
+ unless $self->{page};
$attrs->{rows} ||= 10;
- $self->count;
return $self->{pager} ||= Data::Page->new(
- $self->{count}, $attrs->{rows}, $self->{page});
+ $self->_count, $attrs->{rows}, $self->{page});
}
-=head2 page($page_num)
+=head2 page
+
+=over 4
+
+=item Arguments: $page_number
-Returns a new resultset for the specified page.
+=item Return Value: $rs
+
+=back
+
+Returns a resultset for the $page_number page of the resultset on which page
+is called, where each page contains a number of rows equal to the 'rows'
+attribute set on the resultset (10 by default).
=cut
my ($self, $page) = @_;
my $attrs = { %{$self->{attrs}} };
$attrs->{page} = $page;
- return $self->new($self->{source}, $attrs);
+ return (ref $self)->new($self->result_source, $attrs);
+}
+
+=head2 new_result
+
+=over 4
+
+=item Arguments: \%vals
+
+=item Return Value: $object
+
+=back
+
+Creates an object in the resultset's result class and returns it.
+
+=cut
+
+sub new_result {
+ my ($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 $self->{cond} eq 'HASH'));
+ my %new = %$values;
+ my $alias = $self->{attrs}{alias};
+ foreach my $key (keys %{$self->{cond}||{}}) {
+ $new{$1} = $self->{cond}{$key} if ($key =~ m/^(?:\Q${alias}.\E)?([^.]+)$/);
+ }
+ my $obj = $self->result_class->new(\%new);
+ $obj->result_source($self->result_source) if $obj->can('result_source');
+ return $obj;
+}
+
+=head2 create
+
+=over 4
+
+=item Arguments: \%vals
+
+=item Return Value: $object
+
+=back
+
+Inserts a record into the resultset and returns the object representing it.
+
+Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
+
+=cut
+
+sub create {
+ my ($self, $attrs) = @_;
+ $self->throw_exception( "create needs a hashref" )
+ unless ref $attrs eq 'HASH';
+ return $self->new_result($attrs)->insert;
+}
+
+=head2 find_or_create
+
+=over 4
+
+=item Arguments: \%vals, \%attrs?
+
+=item Return Value: $object
+
+=back
+
+ $class->find_or_create({ key => $val, ... });
+
+Searches for a record matching the search condition; if it doesn't find one,
+creates one and returns that instead.
+
+ my $cd = $schema->resultset('CD')->find_or_create({
+ cdid => 5,
+ artist => 'Massive Attack',
+ title => 'Mezzanine',
+ year => 2005,
+ });
+
+Also takes an optional C<key> attribute, to search by a specific key or unique
+constraint. For example:
+
+ my $cd = $schema->resultset('CD')->find_or_create(
+ {
+ artist => 'Massive Attack',
+ title => 'Mezzanine',
+ },
+ { key => 'artist_title' }
+ );
+
+See also L</find> and L</update_or_create>.
+
+=cut
+
+sub find_or_create {
+ my $self = shift;
+ my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
+ my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
+ my $exists = $self->find($hash, $attrs);
+ return defined $exists ? $exists : $self->create($hash);
+}
+
+=head2 update_or_create
+
+=over 4
+
+=item Arguments: \%col_values, { key => $unique_constraint }?
+
+=item Return Value: $object
+
+=back
+
+ $class->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
+found, updates it with the other given column values. Otherwise, creates a new
+row.
+
+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_create(
+ {
+ artist => 'Massive Attack',
+ title => 'Mezzanine',
+ year => 1998,
+ },
+ { key => 'artist_title' }
+ );
+
+If no C<key> is specified, it searches on all unique constraints defined on the
+source, including the primary key.
+
+If the C<key> is specified as C<primary>, it searches only on the primary key.
+
+See also L</find> and L</find_or_create>.
+
+=cut
+
+sub update_or_create {
+ my $self = shift;
+ my $attrs = (@_ > 1 && ref $_[$#_] eq 'HASH' ? pop(@_) : {});
+ my $hash = ref $_[0] eq 'HASH' ? shift : {@_};
+
+ my %unique_constraints = $self->result_source->unique_constraints;
+ my @constraint_names = (exists $attrs->{key}
+ ? ($attrs->{key})
+ : keys %unique_constraints);
+
+ my @unique_hashes;
+ foreach my $name (@constraint_names) {
+ my @unique_cols = @{ $unique_constraints{$name} };
+ my %unique_hash =
+ map { $_ => $hash->{$_} }
+ grep { exists $hash->{$_} }
+ @unique_cols;
+
+ push @unique_hashes, \%unique_hash
+ if (scalar keys %unique_hash == scalar @unique_cols);
+ }
+
+ if (@unique_hashes) {
+ my $row = $self->single(\@unique_hashes);
+ if (defined $row) {
+ $row->update($hash);
+ return $row;
+ }
+ }
+
+ return $self->create($hash);
+}
+
+=head2 get_cache
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: \@cache_objects?
+
+=back
+
+Gets the contents of the cache for the resultset, if the cache is set.
+
+=cut
+
+sub get_cache {
+ shift->{all_cache};
+}
+
+=head2 set_cache
+
+=over 4
+
+=item Arguments: \@cache_objects
+
+=item Return Value: \@cache_objects
+
+=back
+
+Sets the contents of the cache for the resultset. Expects an arrayref
+of objects of the same class as those produced by the resultset. Note that
+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.
+
+=cut
+
+sub set_cache {
+ my ( $self, $data ) = @_;
+ $self->throw_exception("set_cache requires an arrayref")
+ if defined($data) && (ref $data ne 'ARRAY');
+ $self->{all_cache} = $data;
}
+=head2 clear_cache
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: []
+
+=back
+
+Clears the cache for the resultset.
+
+=cut
+
+sub clear_cache {
+ shift->set_cache(undef);
+}
+
+=head2 related_resultset
+
+=over 4
+
+=item Arguments: $relationship_name
+
+=item Return Value: $resultset
+
+=back
+
+Returns a related resultset for the supplied relationship name.
+
+ $artist_rs = $schema->resultset('CD')->related_resultset('Artist');
+
+=cut
+
+sub related_resultset {
+ my ( $self, $rel ) = @_;
+ $self->{related_resultsets} ||= {};
+ return $self->{related_resultsets}{$rel} ||= do {
+ #warn "fetching related resultset for rel '$rel'";
+ my $rel_obj = $self->result_source->relationship_info($rel);
+ $self->throw_exception(
+ "search_related: result source '" . $self->result_source->name .
+ "' has no such relationship ${rel}")
+ unless $rel_obj; #die Dumper $self->{attrs};
+
+ my $rs = $self->search(undef, { join => $rel });
+ my $alias = defined $rs->{attrs}{seen_join}{$rel}
+ && $rs->{attrs}{seen_join}{$rel} > 1
+ ? join('_', $rel, $rs->{attrs}{seen_join}{$rel})
+ : $rel;
+
+ $self->result_source->schema->resultset($rel_obj->{class}
+ )->search( undef,
+ { %{$rs->{attrs}},
+ alias => $alias,
+ select => undef,
+ as => undef }
+ );
+ };
+}
+
+=head2 throw_exception
+
+See L<DBIx::Class::Schema/throw_exception> for details.
+
+=cut
+
+sub throw_exception {
+ my $self=shift;
+ $self->result_source->schema->throw_exception(@_);
+}
+
+# XXX: FIXME: Attributes docs need clearing up
+
=head1 ATTRIBUTES
-The resultset takes various attributes that modify its behavior.
-Here's an overview of them:
+The resultset takes various attributes that modify its behavior. Here's an
+overview of them:
=head2 order_by
+=over 4
+
+=item Value: ($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<foo DESC> for a
-descending order.
+through directly to SQL, so you can give e.g. C<year DESC> for a
+descending order on the column `year'.
+
+=head2 columns
+
+=over 4
+
+=item Value: \@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.)
+
+=head2 include_columns
+
+=over 4
+
+=item Value: \@columns
+
+=back
+
+Shortcut to include additional columns in the returned results - for example
+
+ $schema->resultset('CD')->search(undef, {
+ include_columns => ['artist.name'],
+ join => ['artist']
+ });
+
+would return all CDs and include a 'name' column to the information
+passed to object inflation
+
+=head2 select
+
+=over 4
+
+=item Value: \@select_columns
-=head2 cols (arrayref)
+=back
-Shortcut to request a particular set of columns to be retrieved - adds
-'me.' onto the start of any column without a '.' in it and sets 'select'
-from that, then auto-populates 'as' from 'select' as normal
+Indicates which columns should be selected from the storage. You can use
+column names, or in the case of RDBMS back ends, function or stored procedure
+names:
-=head2 select (arrayref)
+ $rs = $schema->resultset('Employee')->search(undef, {
+ select => [
+ 'name',
+ { count => 'employeeid' },
+ { sum => 'salary' }
+ ]
+ });
-Indicates which columns should be selected from the storage
+When you use function/stored procedure names and do not supply an C<as>
+attribute, the column names returned are storage-dependent. E.g. MySQL would
+return a column named C<count(employeeid)> in the above example.
-=head2 as (arrayref)
+=head2 as
-Indicates column names for object inflation
+=over 4
+
+=item Value: \@inflation_names
+
+=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
+procedure names:
+
+ $rs = $schema->resultset('Employee')->search(undef, {
+ select => [
+ 'name',
+ { count => 'employeeid' }
+ ],
+ as => ['name', 'employee_count'],
+ });
+
+ my $employee = $rs->first(); # get the first Employee
+
+If the object against which the search is performed already has an accessor
+matching a column name specified in C<as>, the value can be retrieved using
+the accessor as normal:
+
+ my $name = $employee->name();
+
+If on the other hand an accessor does not exist in the object, you need to
+use C<get_column> instead:
+
+ my $employee_count = $employee->get_column('employee_count');
+
+You can create your own accessors if required - see
+L<DBIx::Class::Manual::Cookbook> for details.
=head2 join
-Contains a list of relationships that should be joined for this query. Can also
-contain a hash reference to refer to that relation's relations. So, if one column
-in your class C<belongs_to> foo and another C<belongs_to> bar, you can do
-C<< join => [qw/ foo bar /] >> to join both (and e.g. use them for C<order_by>).
-If a foo contains many margles and you want to join those too, you can do
-C<< join => { foo => 'margle' } >>. If you want to fetch the columns from the
-related table as well, see C<prefetch> below.
+=over 4
+
+=item Value: ($rel_name | \@rel_names | \%rel_names)
+
+=back
+
+Contains a list of relationships that should be joined for this query. For
+example:
+
+ # Get CDs by Nine Inch Nails
+ my $rs = $schema->resultset('CD')->search(
+ { 'artist.name' => 'Nine Inch Nails' },
+ { join => 'artist' }
+ );
+
+Can also contain a hash reference to refer to the other relation's relations.
+For example:
+
+ package MyApp::Schema::Track;
+ use base qw/DBIx::Class/;
+ __PACKAGE__->table('track');
+ __PACKAGE__->add_columns(qw/trackid cd position title/);
+ __PACKAGE__->set_primary_key('trackid');
+ __PACKAGE__->belongs_to(cd => 'MyApp::Schema::CD');
+ 1;
+
+ # In your application
+ my $rs = $schema->resultset('Artist')->search(
+ { 'track.title' => 'Teardrop' },
+ {
+ join => { cd => 'track' },
+ order_by => 'artist.name',
+ }
+ );
+
+If the same join is supplied twice, it will be aliased to <rel>_2 (and
+similarly for a third time). For e.g.
+
+ my $rs = $schema->resultset('Artist')->search({
+ 'cds.title' => 'Down to Earth',
+ 'cds_2.title' => 'Popular',
+ }, {
+ join => [ qw/cds cds/ ],
+ });
+
+will return a set of all artists that have both a cd with title 'Down
+to Earth' and a cd with title 'Popular'.
+
+If you want to fetch related objects from other tables as well, see C<prefetch>
+below.
=head2 prefetch
-Contains a list of relationships that should be fetched along with the main
-query (when they are accessed afterwards they will have already been
-"prefetched"). This is useful for when you know you will need the related
-object(s), because it saves a query. Currently limited to prefetching
-one relationship deep, so unlike C<join>, prefetch must be an arrayref.
+=over 4
-=head2 from
+=item Value: ($rel_name | \@rel_names | \%rel_names)
-This attribute can contain a arrayref of elements. Each element can be another
-arrayref, to nest joins, or it can be a hash which represents the two sides
-of the join.
+=back
-NOTE: Use this on your own risk. This allows you to shoot your foot off!
+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:
+
+ my $rs = $schema->resultset('Tag')->search(
+ undef,
+ {
+ prefetch => {
+ cd => 'artist'
+ }
+ }
+ );
+
+The initial search results in SQL like the following:
+
+ SELECT tag.*, cd.*, artist.* FROM tag
+ JOIN cd ON tag.cd = cd.cdid
+ JOIN artist ON cd.artist = artist.artistid
+
+L<DBIx::Class> has no need to go back to the database when we access the
+C<cd> or C<artist> relationships, which saves us two SQL statements in this
+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.
+
+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').
+
+=head2 from
+
+=over 4
+
+=item Value: \@from_clause
+
+=back
+
+The C<from> attribute gives you manual control over the C<FROM> clause of SQL
+statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
+clauses.
+
+NOTE: Use this on your own risk. This allows you to shoot off your foot!
+C<join> will usually do what you need and it is strongly recommended that you
+avoid using C<from> unless you cannot achieve the desired result using C<join>.
+
+In simple terms, C<from> works as follows:
+
+ [
+ { <alias> => <table>, -join_type => 'inner|left|right' }
+ [] # nested JOIN (optional)
+ { <table.column> => <foreign_table.foreign_key> }
+ ]
+
+ JOIN
+ <alias> <table>
+ [JOIN ...]
+ ON <table.column> = <foreign_table.foreign_key>
+
+An easy way to follow the examples below is to remember the following:
+
+ Anything inside "[]" is a JOIN
+ Anything inside "{}" is a condition for the enclosing JOIN
+
+The following examples utilize a "person" table in a family tree application.
+In order to express parent->child relationships, this table is self-joined:
+
+ # Person->belongs_to('father' => 'Person');
+ # Person->belongs_to('mother' => 'Person');
+
+C<from> can be used to nest joins. Here we return all children with a father,
+then search against all mothers of those children:
+
+ $rs = $schema->resultset('Person')->search(
+ undef,
+ {
+ alias => 'mother', # alias columns in accordance with "from"
+ from => [
+ { mother => 'person' },
+ [
+ [
+ { child => 'person' },
+ [
+ { father => 'person' },
+ { 'father.person_id' => 'child.father_id' }
+ ]
+ ],
+ { 'mother.person_id' => 'child.mother_id' }
+ ],
+ ]
+ },
+ );
+
+ # Equivalent SQL:
+ # SELECT mother.* FROM person mother
+ # JOIN (
+ # person child
+ # JOIN person father
+ # ON ( father.person_id = child.father_id )
+ # )
+ # ON ( mother.person_id = child.mother_id )
+
+The type of any join can be controlled manually. To search against only people
+with a father in the person table, we could explicitly use C<INNER JOIN>:
+
+ $rs = $schema->resultset('Person')->search(
+ undef,
+ {
+ alias => 'child', # alias columns in accordance with "from"
+ from => [
+ { child => 'person' },
+ [
+ { father => 'person', -join_type => 'inner' },
+ { 'father.id' => 'child.father_id' }
+ ],
+ ]
+ },
+ );
+
+ # Equivalent SQL:
+ # SELECT child.* FROM person child
+ # INNER JOIN person father ON child.father_id = father.id
=head2 page
-For a paged resultset, specifies which page to retrieve. Leave unset
-for an unpaged resultset.
+=over 4
+
+=item Value: $page
+
+=back
+
+Makes the resultset paged and specifies the page to retrieve. Effectively
+identical to creating a non-pages resultset and then calling ->page($page)
+on it.
=head2 rows
-For a paged resultset, how many rows per page
+=over 4
+
+=item Value: $rows
+
+=back
+
+Specifes the maximum number of rows for direct retrieval or the number of
+rows per page if the page attribute or method is used.
=head2 group_by
-A list of columns to group by (note that 'count' doesn't work on grouped
-resultsets)
+=over 4
+
+=item Value: \@columns
+
+=back
+
+A arrayref of columns to group by. Can include columns of joined tables.
+
+ group_by => [qw/ column1 column2 ... /]
+
+=head2 having
+
+=over 4
+
+=item Value: $condition
+
+=back
+
+HAVING is a select statement attribute that is applied between GROUP BY and
+ORDER BY. It is applied to the after the grouping calculations have been
+done.
+
+ having => { 'count(employee)' => { '>=', 100 } }
=head2 distinct
-Set to 1 to group by all columns
+=over 4
+
+=item Value: (0 | 1)
+
+=back
+
+Set to 1 to group by all columns.
+
+=head2 cache
+
+Set to 1 to cache search results. This prevents extra SQL queries if you
+revisit rows in your ResultSet:
+
+ my $resultset = $schema->resultset('Artist')->search( undef, { cache => 1 } );
+
+ while( my $artist = $resultset->next ) {
+ ... do stuff ...
+ }
+
+ $rs->first; # without cache, this would issue a query
+
+By default, searches are not cached.
+
+For more examples of using these attributes, see
+L<DBIx::Class::Manual::Cookbook>.
=cut
projects / dbsrgits/DBIx-Class.git / blobdiff