fix comments

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / ResultSetColumn.pm

diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm
index 78fd44a..3ed9342 100644 (file)
--- a/lib/DBIx/Class/ResultSetColumn.pm
+++ b/lib/DBIx/Class/ResultSetColumn.pm
@@ -36,25 +36,36 @@ passed as params. Used internally by L<DBIx::Class::ResultSet/get_column>.
 sub new {
   my ($class, $rs, $column) = @_;
   $class = ref $class if ref $class;
+
+  $rs->throw_exception("column must be supplied") unless $column;
+
   my $new_parent_rs = $rs->search_rs; # we don't want to mess up the original, so clone it
-  my $attrs = $new_parent_rs->_resolved_attrs;
-  $new_parent_rs->{attrs}->{$_} = undef for qw(prefetch include_columns +select +as); # prefetch, include_columns, +select, +as cause additional columns to be fetched
+
+  # prefetch causes additional columns to be fetched, but we can not just make a new
+  # rs via the _resolved_attrs trick - we need to retain the separation between
+  # +select/+as and select/as
+  for my $attr (qw/prefetch collapse/) {
+    for (qw/attrs _attrs/) {
+      delete $new_parent_rs->{$_}{$attr} if ref $new_parent_rs->{$_};
+    }
+  }
 
   # If $column can be found in the 'as' list of the parent resultset, use the
   # corresponding element of its 'select' list (to keep any custom column
   # definition set up with 'select' or '+select' attrs), otherwise use $column
   # (to create a new column definition on-the-fly).
+  my $attrs = $new_parent_rs->_resolved_attrs;
+
   my $as_list = $attrs->{as} || [];
   my $select_list = $attrs->{select} || [];
   my $as_index = List::Util::first { ($as_list->[$_] || "") eq $column } 0..$#$as_list;
   my $select = defined $as_index ? $select_list->[$as_index] : $column;
 
   my $new = bless { _select => $select, _as => $column, _parent_resultset => $new_parent_rs }, $class;
-  $new->throw_exception("column must be supplied") unless $column;
   return $new;
 }
 
-=head2 as_query
+=head2 as_query (EXPERIMENTAL)
 
 =over 4
 
@@ -66,9 +77,13 @@ sub new {
 
 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->_resultset->as_query }
+sub as_query { return shift->_resultset->as_query(@_) }
 
 =head2 next
 
@@ -184,6 +199,24 @@ sub min {
   return shift->func('MIN');
 }
 
+=head2 min_rs
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+  my $rs = $year_col->min_rs();
+
+Wrapper for ->func_rs for function MIN().
+
+=cut
+
+sub min_rs { return shift->func_rs('MIN') }
+
 =head2 max
 
 =over 4
@@ -205,6 +238,24 @@ sub max {
   return shift->func('MAX');
 }
 
+=head2 max_rs
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+  my $rs = $year_col->max_rs();
+
+Wrapper for ->func_rs for function MAX().
+
+=cut
+
+sub max_rs { return shift->func_rs('MAX') }
+
 =head2 sum
 
 =over 4
@@ -226,6 +277,24 @@ sub sum {
   return shift->func('SUM');
 }
 
+=head2 sum_rs
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+  my $rs = $year_col->sum_rs();
+
+Wrapper for ->func_rs for function SUM().
+
+=cut
+
+sub sum_rs { return shift->func_rs('SUM') }
+
 =head2 func
 
 =over 4
@@ -248,7 +317,7 @@ value. Produces the following SQL:
 
 sub func {
   my ($self,$function) = @_;
-  my $cursor = $self->{_parent_resultset}->search(undef, {select => {$function => $self->{_select}}, as => [$self->{_as}]})->cursor;
+  my $cursor = $self->func_rs($function)->cursor;
   
   if( wantarray ) {
     return map { $_->[ 0 ] } $cursor->all;
@@ -257,6 +326,30 @@ sub func {
   return ( $cursor->next )[ 0 ];
 }
 
+=head2 func_rs
+
+=over 4
+
+=item Arguments: $function
+
+=item Return Value: $resultset
+
+=back
+
+Creates the resultset that C<func()> uses to run its query.
+
+=cut
+
+sub func_rs {
+  my ($self,$function) = @_;
+  return $self->{_parent_resultset}->search(
+    undef, {
+      select => {$function => $self->{_select}},
+      as => [$self->{_as}],
+    },
+  );
+}
+
 =head2 throw_exception
 
 See L<DBIx::Class::Schema/throw_exception> for details.