X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSetColumn.pm;h=12623a3370da64817648cf2ea1c3a1af129d48cd;hb=37aafa2ede65e38af8fe9eda374ad4626290932f;hp=4f48d330384563446542c305f61592a77ac15e93;hpb=d4daee7b54e38e4b3d3d0a77759bddc1a4ede6e5;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm index 4f48d33..12623a3 100644 --- a/lib/DBIx/Class/ResultSetColumn.pm +++ b/lib/DBIx/Class/ResultSetColumn.pm @@ -1,8 +1,13 @@ package DBIx::Class::ResultSetColumn; + use strict; use warnings; + use base 'DBIx::Class'; -use List::Util; + +use Carp::Clan qw/^DBIx::Class/; +use DBIx::Class::Exception; +use List::Util (); =head1 NAME @@ -37,32 +42,51 @@ sub new { my ($class, $rs, $column) = @_; $class = ref $class if ref $class; - $rs->throw_exception("column must be supplied") unless $column; + $rs->throw_exception('column must be supplied') unless $column; my $orig_attrs = $rs->_resolved_attrs; - my $new_parent_rs = $rs->search_rs; - - # 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. At the same time we want to preserve any joins that the - # prefetch would otherwise generate. - - my $new_attrs = $new_parent_rs->{attrs} ||= {}; - $new_attrs->{join} = $rs->_merge_attr( delete $new_attrs->{join}, delete $new_attrs->{prefetch} ); + my $alias = $rs->current_source_alias; # 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 $as_list = $orig_attrs->{as} || []; my $select_list = $orig_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_parent_rs; + # analyze the order_by, and see if it is done over a function/nonexistentcolumn + # if this is the case we will need to wrap a subquery since the result of RSC + # *must* be a single column select + my %collist = map + { $_ => 1, ($_ =~ /\./) ? () : ( "$alias.$_" => 1 ) } + ($rs->result_source->columns, $column) + ; + if ( + scalar grep + { ! $collist{$_} } + ( $rs->result_source->schema->storage->_extract_order_columns ($orig_attrs->{order_by} ) ) + ) { + # nuke the prefetch before collapsing to sql + my $subq_rs = $rs->search; + $subq_rs->{attrs}{join} = $subq_rs->_merge_joinpref_attr( $subq_rs->{attrs}{join}, delete $subq_rs->{attrs}{prefetch} ); + $new_parent_rs = $subq_rs->as_subselect_rs; + } + + $new_parent_rs ||= $rs->search_rs; + my $new_attrs = $new_parent_rs->{attrs} ||= {}; + + # 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. At the same time we want to preserve any joins that the + # prefetch would otherwise generate. + $new_attrs->{join} = $rs->_merge_joinpref_attr( $new_attrs->{join}, delete $new_attrs->{prefetch} ); + # {collapse} would mean a has_many join was injected, which in turn means - # we need to group IF WE CAN (only if the column in question is unique) - if (!$new_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) { + # we need to group *IF WE CAN* (only if the column in question is unique) + if (!$orig_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) { # scan for a constraint that would contain our column only - that'd be proof # enough it is unique @@ -76,16 +100,24 @@ sub new { if ($col eq $select or $fqcol eq $select) { $new_attrs->{group_by} = [ $select ]; + delete $new_attrs->{distinct}; # it is ignored when group_by is present last; } } + + if (!$new_attrs->{group_by}) { + carp ( + "Attempting to retrieve non-unique column '$column' on a resultset containing " + . 'one-to-many joins will return duplicate results.' + ); + } } my $new = bless { _select => $select, _as => $column, _parent_resultset => $new_parent_rs }, $class; return $new; } -=head2 as_query (EXPERIMENTAL) +=head2 as_query =over 4 @@ -99,8 +131,6 @@ Returns the SQL query and bind vars associated with the invocant. This is generally used as the RHS for a subquery. -B: This feature is still experimental. - =cut sub as_query { return shift->_resultset->as_query(@_) } @@ -125,7 +155,10 @@ one value. sub next { my $self = shift; + + # using cursor so we don't inflate anything my ($row) = $self->_resultset->cursor->next; + return $row; } @@ -149,6 +182,8 @@ than row objects. sub all { my $self = shift; + + # using cursor so we don't inflate anything return map { $_->[0] } $self->_resultset->cursor->all; } @@ -194,7 +229,38 @@ Much like L but just returning the one value. sub first { my $self = shift; - my ($row) = $self->_resultset->cursor->reset->next; + + # using cursor so we don't inflate anything + $self->_resultset->cursor->reset; + my ($row) = $self->_resultset->cursor->next; + + return $row; +} + +=head2 single + +=over 4 + +=item Arguments: none + +=item Return Value: $value + +=back + +Much like L fetches one and only one column +value using the cursor directly. If additional rows are present a warning +is issued before discarding the cursor. + +=cut + +sub single { + my $self = shift; + + my $attrs = $self->_resultset->_resolved_attrs; + my ($row) = $self->_resultset->result_source->storage->select_single( + $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs + ); + return $row; } @@ -378,10 +444,12 @@ See L for details. sub throw_exception { my $self=shift; + if (ref $self && $self->{_parent_resultset}) { - $self->{_parent_resultset}->throw_exception(@_) - } else { - croak(@_); + $self->{_parent_resultset}->throw_exception(@_); + } + else { + DBIx::Class::Exception->throw(@_); } } @@ -395,7 +463,7 @@ sub throw_exception { # # Returns the underlying resultset. Creates it from the parent resultset if # necessary. -# +# sub _resultset { my $self = shift;