X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSetColumn.pm;h=60d08c76cba86fb24aec624039f8f900740c4482;hb=0c11ad0ee5c8407f6b87d6e15c62a1b445076dc0;hp=1596e53b84720f8ec24952f0e38da83297dcd2df;hpb=d8dbe471a2f98a0bc2de5e629f22ee2f2ec034ef;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm index 1596e53..60d08c7 100644 --- a/lib/DBIx/Class/ResultSetColumn.pm +++ b/lib/DBIx/Class/ResultSetColumn.pm @@ -1,8 +1,14 @@ package DBIx::Class::ResultSetColumn; + use strict; use warnings; + use base 'DBIx::Class'; -use List::Util; +use DBIx::Class::Carp; +use DBIx::Class::Exception; + +# not importing first() as it will clash with our own method +use List::Util (); =head1 NAME @@ -37,47 +43,68 @@ 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; + my $rsrc = $rs->result_source; # 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] : $column; - # {collapse} would mean a has_many join was injected, which in turn means - # we need to group IF WE CAN (only if the column in question is unique) - if (!$new_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) { + my ($new_parent_rs, $colmap); + for ($rsrc->columns, $column) { + if ($_ =~ /^ \Q$alias\E \. ([^\.]+) $ /x) { + $colmap->{$_} = $1; + } + elsif ($_ !~ /\./) { + $colmap->{"$alias.$_"} = $_; + $colmap->{$_} = $_; + } + } - # scan for a constraint that would contain our column only - that'd be proof - # enough it is unique - my $constraints = { $rs->result_source->unique_constraints }; - for my $constraint_columns ( values %$constraints ) { + # 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 + if ( + scalar grep + { ! exists $colmap->{$_->[0]} } + ( $rsrc->schema->storage->_extract_order_criteria ($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 = $new_parent_rs->{attrs} ||= {}; - next unless @$constraint_columns == 1; + # 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} ); - my $col = $constraint_columns->[0]; - my $fqcol = join ('.', $new_attrs->{alias}, $col); + # {collapse} would mean a has_many join was injected, which in turn means + # we need to group *IF WE CAN* (only if the column in question is unique) + if (!$orig_attrs->{group_by} && keys %{$orig_attrs->{collapse}}) { - if ($col eq $select or $fqcol eq $select) { - $new_attrs->{group_by} = [ $select ]; - last; - } + if ($colmap->{$select} and $rsrc->_identifying_column_set([$colmap->{$select}])) { + $new_attrs->{group_by} = [ $select ]; + delete $new_attrs->{distinct}; # it is ignored when group_by is present + } + else { + carp ( + "Attempting to retrieve non-unique column '$column' on a resultset containing " + . 'one-to-many joins will return duplicate results.' + ); } } @@ -85,7 +112,7 @@ sub new { return $new; } -=head2 as_query (EXPERIMENTAL) +=head2 as_query =over 4 @@ -99,8 +126,6 @@ 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(@_) } @@ -118,14 +143,17 @@ sub as_query { return shift->_resultset->as_query(@_) } Returns the next value of the column in the resultset (or C if there is none). -Much like L but just returning the +Much like L but just returning the one value. =cut sub next { my $self = shift; + + # using cursor so we don't inflate anything my ($row) = $self->_resultset->cursor->next; + return $row; } @@ -149,6 +177,8 @@ 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 +224,38 @@ 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 $row; } @@ -338,7 +399,7 @@ value. Produces the following SQL: sub func { my ($self,$function) = @_; my $cursor = $self->func_rs($function)->cursor; - + if( wantarray ) { return map { $_->[ 0 ] } $cursor->all; } @@ -373,15 +434,17 @@ sub func_rs { =head2 throw_exception See L for details. - -=cut - + +=cut + 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 +458,7 @@ sub throw_exception { # # Returns the underlying resultset. Creates it from the parent resultset if # necessary. -# +# sub _resultset { my $self = shift; @@ -409,11 +472,9 @@ sub _resultset { 1; -=head1 AUTHORS - -Luke Saunders +=head1 AUTHOR AND CONTRIBUTORS -Jess Robinson +See L and L in DBIx::Class =head1 LICENSE