X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSet.pm;h=da955a47a339ab1e9f39c482977008d217ec7c8c;hb=7ed3d6dc7d83264aa67108ec304985c0116d6009;hp=ce038dbbfbb9a46db53ea2018f7b5bd3e397707d;hpb=cda04c3afd46989e1964a6c8a277fd7faa11b291;p=dbsrgits%2FDBIx-Class.git

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index ce038db..da955a4 100644
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -3,9 +3,16 @@ package DBIx::Class::ResultSet;
 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
 
@@ -13,109 +20,201 @@ DBIx::Class::ResultSet - Responsible for fetching and creating resultset.
 
 =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('Foo')->search(bar => 'baz');
 
 =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($db_class, \%$attrs)
+=head2 new
+
+=head3 Arguments: ($source, \%$attrs)
+
+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.
+
+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:
 
-The resultset constructor. Takes a table class 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.
+  my $rs = $schema->resultset('CD')->search({ title => '100th Window' });
 
 =cut
 
 sub new {
-  my ($class, $source, $attrs) = @_;
-  #use Data::Dumper; warn Dumper(@_);
-  $class = ref $class if ref $class;
-  $attrs = { %{ $attrs || {} } };
+  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');
+  
+  $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);
+  }
+  #use Data::Dumper; warn Dumper(@{$attrs}{qw/select as/});
+
+  $attrs->{from} ||= [ { $alias => $source->from } ];
+  $attrs->{seen_join} ||= {};
   my %seen;
-  $attrs->{cols} ||= [ map { "me.$_" } $source->columns ];
-  $attrs->{from} ||= [ { 'me' => $source->name } ];
-  if ($attrs->{join}) {
-    foreach my $j (ref $attrs->{join} eq 'ARRAY'
-              ? (@{$attrs->{join}}) : ($attrs->{join})) {
+  if (my $join = delete $attrs->{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}}, $source->result_class->_resolve_join($attrs->{join}, 'me'));
+    push(@{$attrs->{from}}, $source->resolve_join($join, $attrs->{alias}, $attrs->{seen_join}));
+  }
+  
+  $attrs->{group_by} ||= $attrs->{select} if delete $attrs->{distinct};
+  $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);
   }
-  foreach my $pre (@{$attrs->{prefetch} || []}) {
-    push(@{$attrs->{from}}, $source->result_class->_resolve_join($pre, 'me'))
-      unless $seen{$pre};
-    push(@{$attrs->{cols}},
-      map { "$pre.$_" }
-      $source->result_class->_relationships->{$pre}->{class}->table->columns);
+  $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,
-    result_class => $source->result_class,
-    cols => $attrs->{cols},
+
+  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);
-  $new->pager if ($attrs->{page});
-  return $new;
+    attrs => $attrs
+  }, $class;
 }
 
 =head2 search
 
-  my @obj    = $rs->search({ foo => 3 }); # "... WHERE foo = 3"              
-  my $new_rs = $rs->search({ foo => 3 });                                    
-                                                                                
+  my @obj    = $rs->search({ foo => 3 }); # "... WHERE foo = 3"
+  my $new_rs = $rs->search({ foo => 3 });
+
 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 foo, bar FROM $class_table"
+  my @all = $class->search(undef, { columns => [qw/foo bar/] });
 
 =cut
 
 sub search {
   my $self = shift;
 
-  #use Data::Dumper;warn Dumper(@_);
-
-  my $attrs = { %{$self->{attrs}} };
-  if (@_ > 1 && ref $_[$#_] eq 'HASH') {
-    $attrs = { %{ pop(@_) } };
-  }
-
-  my $where = ((@_ == 1 || ref $_[0] eq "HASH") ? shift : {@_});
-  if (defined $where) {
-    $where = (defined $attrs->{where}
-                ? { '-and' => [ $where, $attrs->{where} ] }
+  my $rs;
+  if( @_ ) {
+    
+    my $attrs = { %{$self->{attrs}} };
+    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);
-    $attrs->{where} = $where;
-  }
+    }
 
-  my $rs = $self->new($self->{source}, $attrs);
+    if (defined $having) {
+      $attrs->{having} = (defined $attrs->{having}
+                ? { '-and' =>
+                    [ map { ref $_ eq 'ARRAY' ? [ -or => $_ ] : $_ }
+                        $having, $attrs->{having} ] }
+                : $having);
+    }
 
+    $rs = (ref $self)->new($self->result_source, $attrs);
+  }
+  else {
+    $rs = $self;
+    $rs->reset;
+  }
   return (wantarray ? $rs->all : $rs);
 }
 
-=head2 search_literal                                                              
+=head2 search_literal
+
   my @obj    = $rs->search_literal($literal_where_cond, @bind);
   my $new_rs = $rs->search_literal($literal_where_cond, @bind);
 
 Pass a literal chunk of SQL to be added to the conditional part of the
-resultset
+resultset.
 
 =cut
-                                                         
+
 sub search_literal {
   my ($self, $cond, @vals) = @_;
   my $attrs = (ref $vals[$#vals] eq 'HASH' ? { %{ pop(@vals) } } : {});
@@ -123,6 +222,79 @@ sub search_literal {
   return $self->search(\$cond, $attrs);
 }
 
+=head2 find
+
+=head3 Arguments: (@colvalues) | (\%cols, \%attrs?)
+
+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 @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->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 (@cols == @vals) {
+    $query = {};
+    @{$query}{@cols} = @vals;
+  } else {
+    $query = {@vals};
+  }
+  foreach my $key (grep { ! m/\./ } keys %$query) {
+    $query->{"$self->{attrs}{alias}.$key"} = delete $query->{$key};
+  }
+  #warn Dumper($query);
+  
+  if (keys %$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?);
+
+Search the specified relationship. Optionally specify a condition for matching
+records.
+
+=cut
+
+sub search_related {
+  return shift->related_resultset(shift)->search(@_);
+}
+
 =head2 cursor
 
 Returns a storage-driven cursor to the given resultset.
@@ -131,34 +303,60 @@ Returns a storage-driven cursor to the given resultset.
 
 sub cursor {
   my ($self) = @_;
-  my ($source, $attrs) = @{$self}{qw/source attrs/};
-  if ($attrs->{page}) {
-    $attrs->{rows} = $self->pager->entries_per_page;
-    $attrs->{offset} = $self->pager->skipped;
-  }
+  my $attrs = { %{$self->{attrs}} };
   return $self->{cursor}
-    ||= $source->storage->select($self->{from}, $self->{cols},
+    ||= $self->result_source->storage->select($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') {
-    $attrs = pop(@_);
+Inflates the first result without creating a cursor
+
+=cut
+
+sub single {
+  my ($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
+
+Perform a search, but use C<LIKE> instead of equality 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, $last)
+=head2 slice
+
+=head3 Arguments: ($first, $last)
 
 Returns a subset of elements from the resultset.
 
@@ -167,95 +365,192 @@ Returns a subset of elements from the resultset.
 sub slice {
   my ($self, $min, $max) = @_;
   my $attrs = { %{ $self->{attrs} || {} } };
-  $self->{source}->result_class->throw("Can't slice without where") unless $attrs->{where};
-  $attrs->{offset} = $min;
+  $attrs->{offset} ||= 0;
+  $attrs->{offset} += $min;
   $attrs->{rows} = ($max ? ($max - $min + 1) : 1);
-  my $slice = $self->new($self->{source}, $attrs);
+  my $slice = (ref $self)->new($self->result_source, $attrs);
   return (wantarray ? $slice->all : $slice);
 }
 
-=head2 next 
+=head2 next
+
+Returns the next element in the resultset (C<undef> is there is none).
 
-Returns the next element in the resultset (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;
+  }
 
 =cut
 
 sub next {
   my ($self) = @_;
-  my @row = $self->cursor->next;
+  if (@{$self->{all_cache} || []}) {
+    $self->{all_cache_position} ||= 0;
+    return $self->{all_cache}->[$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}{cols} };
-  s/^me\.// for @cols;
-  @cols = grep { /\(/ or ! /\./ } @cols;
-  my $new;
-  unless ($self->{attrs}{prefetch}) {
-    $new = $self->{source}->result_class->_row_to_object(\@cols, \@row);
-  } else {
-    my @main = splice(@row, 0, scalar @cols);
-    $new = $self->{source}->result_class->_row_to_object(\@cols, \@main);
-    PRE: foreach my $pre (@{$self->{attrs}{prefetch}}) {
-      my $rel_obj = $self->{source}->result_class->_relationships->{$pre};
-      my $pre_class = $self->{source}->result_class->resolve_class($rel_obj->{class});
-      my @pre_cols = $pre_class->_select_columns;
-      my @vals = splice(@row, 0, scalar @pre_cols);
-      my $fetched = $pre_class->_row_to_object(\@pre_cols, \@vals);
-      $self->{source}->result_class->throw("No accessor for prefetched $pre")
-        unless defined $rel_obj->{attrs}{accessor};
-      if ($rel_obj->{attrs}{accessor} eq 'single') {
-        foreach my $pri ($rel_obj->{class}->primary_columns) {
-          unless (defined $fetched->get_column($pri)) {
-            undef $fetched;
-            last;
-          }
-        }
-        $new->{_relationship_data}{$pre} = $fetched;
-      } elsif ($rel_obj->{attrs}{accessor} eq 'filter') {
-        $new->{_inflated_column}{$pre} = $fetched;
-      } else {
-        $self->{source}->result_class->throw("Don't know how to store prefetched $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 = (defined($prefix)
+                   ? (map { (m/^\Q${prefix}.\E(.+)$/ ? ($1) : ()); }
+                       keys %{$self->{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, $c_prefix);
+      #warn Data::Dumper::Dumper($tree, $row);
+    }
+    @$target = @final;
+  }
+
+  return $info;
+}
+
+=head2 result_source
+
+Returns a reference to the result source for this recordset.
+
+=cut
+
+
 =head2 count
 
 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];
+  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;
+}
+
+sub _count { # Separated out so pager can get the full count
+  my $self = shift;
+  my $select = { count => '*' };
   my $attrs = { %{ $self->{attrs} } };
-  unless ($self->{count}) {
-    # offset and order by are not needed to count
-    delete $attrs->{$_} for qw/offset order_by/;
-        
-    my @cols = 'COUNT(*)';
-    $self->{count} = $self->{source}->storage->select_single(
-        $self->{from}, \@cols, $self->{cond}, $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;
   }
-  return 0 unless $self->{count};
-  return $self->{pager}->entries_on_this_page if ($self->{pager});
-  return ( $attrs->{rows} && $attrs->{rows} < $self->{count} ) 
-    ? $attrs->{rows} 
-    : $self->{count};
+
+  $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.
+Calls L</search_literal> with the passed arguments, then L</count>.
 
 =cut
 
@@ -270,8 +565,29 @@ is returned in list context.
 
 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
@@ -282,6 +598,7 @@ Resets the resultset's cursor, so you can iterate through the elements again.
 
 sub reset {
   my ($self) = @_;
+  $self->{all_cache_position} = 0;
   $self->cursor->reset;
   return $self;
 }
@@ -296,39 +613,119 @@ sub first {
   return $_[0]->reset->next;
 }
 
+=head2 update
+
+=head3 Arguments: (\%values)
+
+Sets the specified columns in the resultset to the supplied values.
+
+=cut
+
+sub update {
+  my ($self, $values) = @_;
+  $self->throw_exception("Values for update must be a hash") unless ref $values eq 'HASH';
+  return $self->result_source->storage->update(
+           $self->result_source->from, $values, $self->{cond});
+}
+
+=head2 update_all
+
+=head3 Arguments: (\%values)
+
+Fetches all objects and updates them one at a time.  Note that C<update_all>
+will run cascade triggers while L</update> will not.
+
+=cut
+
+sub update_all {
+  my ($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.
+Deletes the contents of the resultset from its result source.
 
 =cut
 
 sub delete {
   my ($self) = @_;
-  $_->delete for $self->all;
+  my $del = {};
+
+  if (!ref($self->{cond})) {
+
+    # No-op. No condition, we're deleting everything
+
+  } elsif (ref $self->{cond} eq 'ARRAY') {
+
+    $del = [ 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') {
+
+      $del->{-and} = [ map { my %hash;
+        foreach my $key (keys %{$_}) {
+          $key =~ /([^.]+)$/;
+          $hash{$1} = $_->{$key};
+        }; \%hash; } @{$self->{cond}{-and}} ];
+
+    } else {
+
+      foreach my $key (keys %{$self->{cond}}) {
+        $key =~ /([^.]+)$/;
+        $del->{$1} = $self->{cond}{$key};
+      }
+    }
+  } else {
+    $self->throw_exception(
+      "Can't delete on resultset with condition unless hash or array");
+  }
+
+  $self->result_source->storage->delete($self->result_source->from, $del);
   return 1;
 }
 
-*delete_all = \&delete; # Yeah, yeah, yeah ...
+=head2 delete_all
+
+Fetches all objects and deletes them one at a time.  Note that C<delete_all>
+will run 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.
+sense for queries with a C<page> attribute.
 
 =cut
 
 sub pager {
   my ($self) = @_;
   my $attrs = $self->{attrs};
-  delete $attrs->{offset};
-  my $rows_per_page = delete $attrs->{rows} || 10;
-  $self->{pager} ||= Data::Page->new(
-    $self->count, $rows_per_page, $attrs->{page} || 1);
-  $attrs->{rows} = $rows_per_page;
-  return $self->{pager};
+  $self->throw_exception("Can't create pager for non-paged rs") unless $self->{page};
+  $attrs->{rows} ||= 10;
+  return $self->{pager} ||= Data::Page->new(
+    $self->_count, $attrs->{rows}, $self->{page});
 }
 
-=head2 page($page_num)
+=head2 page
+
+=head3 Arguments: ($page_num)
 
 Returns a new resultset for the specified page.
 
@@ -336,60 +733,524 @@ Returns a new resultset for the specified page.
 
 sub page {
   my ($self, $page) = @_;
-  my $attrs = $self->{attrs};
+  my $attrs = { %{$self->{attrs}} };
   $attrs->{page} = $page;
-  return $self->new($self->{source}, $attrs);
+  return (ref $self)->new($self->result_source, $attrs);
+}
+
+=head2 new_result
+
+=head3 Arguments: (\%vals)
+
+Creates a result in the resultset's result class.
+
+=cut
+
+sub new_result {
+  my ($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 $obj;
+}
+
+=head2 create
+
+=head3 Arguments: (\%vals)
+
+Inserts a record into the resultset and returns the object.
+
+Effectively a shortcut for C<< ->new_result(\%vals)->insert >>.
+
+=cut
+
+sub create {
+  my ($self, $attrs) = @_;
+  $self->throw_exception( "create needs a hashref" ) unless ref $attrs eq 'HASH';
+  return $self->new_result($attrs)->insert;
+}
+
+=head2 find_or_create
+
+=head3 Arguments: (\%vals, \%attrs?)
+
+  $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
+
+  $class->update_or_create({ key => $val, ... });
+
+First, search 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, update it with the other given column values.  Otherwise, create 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>, search 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) {
+      $row->set_columns($hash);
+      $row->update;
+      return $row;
+    }
+  }
+
+  return $self->create($hash);
+}
+
+=head2 get_cache
+
+Gets the contents of the cache for the resultset.
+
+=cut
+
+sub get_cache {
+  shift->{all_cache} || [];
+}
+
+=head2 set_cache
+
+Sets the contents of the cache for the resultset. Expects an arrayref of objects of the same class as those produced by the resultset.
+
+=cut
+
+sub set_cache {
+  my ( $self, $data ) = @_;
+  $self->throw_exception("set_cache requires an arrayref")
+    if ref $data ne 'ARRAY';
+  my $result_class = $self->result_class;
+  foreach( @$data ) {
+    $self->throw_exception("cannot cache object of type '$_', expected '$result_class'")
+      if ref $_ ne $result_class;
+  }
+  $self->{all_cache} = $data;
+}
+
+=head2 clear_cache
+
+Clears the cache for the resultset.
+
+=cut
+
+sub clear_cache {
+  shift->set_cache([]);
+}
+
+=head2 related_resultset
+
+Returns a related resultset for the supplied relationship name.
+
+  $rs = $rs->related_resultset('foo');
+
+=cut
+
+sub related_resultset {
+  my ( $self, $rel, @rest ) = @_;
+  $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 }
+           )->search(@rest);      
+  };
+}
+
+=head2 throw_exception
+
+See Schema's throw_exception
+
+=cut
+
+sub throw_exception {
+  my $self=shift;
+  $self->result_source->schema->throw_exception(@_);
 }
 
-=head1 Attributes
+=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
 
-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.
+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.
+
+=head2 columns
+
+=head3 Arguments: (arrayref)
+
+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
+
+=head3 Arguments: (arrayref)
+
+Shortcut to include additional columns in the returned results - for example
 
-=head2 cols
+  { include_columns => ['foo.name'], join => ['foo'] }
 
-Which columns should be retrieved.
+would add a 'name' column to the information passed to object inflation
+
+=head2 select
+
+=head3 Arguments: (arrayref)
+
+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:
+
+  $rs = $schema->resultset('Foo')->search(
+    undef,
+    {
+      select => [
+        'column_name',
+        { count => 'column_to_count' },
+        { sum => 'column_to_sum' }
+      ]
+    }
+  );
+
+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(column_to_count)> in the above example.
+
+=head2 as
+
+=head3 Arguments: (arrayref)
+
+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('Foo')->search(
+    undef,
+    {
+      select => [
+        'column1',
+        { count => 'column2' }
+      ],
+      as => [qw/ column1 column2_count /]
+    }
+  );
+
+  my $foo = $rs->first(); # get the first Foo
+
+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 $column1 = $foo->column1();
+
+If on the other hand an accessor does not exist in the object, you need to
+use C<get_column> instead:
+
+  my $column2_count = $foo->get_column('column2_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.
+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',
+    }
+  );
 
-=head2 prefetch
+If the same join is supplied twice, it will be aliased to <rel>_2 (and
+similarly for a third time). For e.g.
 
-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.
+  my $rs = $schema->resultset('Artist')->search(
+    { 'cds.title'   => 'Foo',
+      'cds_2.title' => 'Bar' },
+    { join => [ qw/cds cds/ ] });
 
-=head2 from 
+will return a set of all artists that have both a cd with title Foo and a cd
+with title Bar.
 
-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. 
+If you want to fetch related objects from other tables as well, see C<prefetch>
+below.
 
-NOTE: Use this on your own risk. This allows you to shoot your foot off!
+=head2 prefetch
+
+=head3 Arguments: arrayref/hashref
+
+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
+
+=head3 Arguments: (arrayref)
+
+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 a paged resultset, specifies which page to retrieve.  Leave unset
 for an unpaged resultset.
 
 =head2 rows
 
-For a paged resultset, how many rows per page
+For a paged resultset, how many rows per page:
+
+  rows => 10
+
+Can also be used to simulate an SQL C<LIMIT>.
+
+=head2 group_by
+
+=head3 Arguments: (arrayref)
+
+A arrayref of columns to group by. Can include columns of joined tables.
+
+  group_by => [qw/ column1 column2 ... /]
+
+=head2 distinct
+
+Set to 1 to group by all columns.
+
+For more examples of using these attributes, see
+L<DBIx::Class::Manual::Cookbook>.
 
 =cut