X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSetColumn.pm;h=5b510de45685b3ae52492cad78562f37ec1675ad;hb=6c5aa1fbffdc9e5679d2f68780b11a9569ec1993;hp=49b84560c3af8b78392ae638985ae412afb07903;hpb=eb98561caf4a8342cd6cc477499ef71120765fee;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/ResultSetColumn.pm b/lib/DBIx/Class/ResultSetColumn.pm index 49b8456..5b510de 100644 --- a/lib/DBIx/Class/ResultSetColumn.pm +++ b/lib/DBIx/Class/ResultSetColumn.pm @@ -1,7 +1,12 @@ package DBIx::Class::ResultSetColumn; + use strict; use warnings; + use base 'DBIx::Class'; +use DBIx::Class::Carp; +use DBIx::Class::_Util qw( fail_on_internal_wantarray fail_on_internal_call ); +use namespace::clean; =head1 NAME @@ -36,14 +41,97 @@ sub new { my ($class, $rs, $column) = @_; $class = ref $class if ref $class; - my $object_ref = { _column => $column, - _parent_resultset => $rs }; - - my $new = bless $object_ref, $class; - $new->throw_exception("column must be supplied") unless ($column); - return $new; + $rs->throw_exception('column must be supplied') unless $column; + + my $orig_attrs = $rs->_resolved_attrs; + 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) = grep { ($as_list->[$_] || "") eq $column } 0..$#$as_list; + my $select = defined $as_index ? $select_list->[$as_index] : $column; + + my $colmap; + for ($rsrc->columns, $column) { + if ($_ =~ /^ \Q$alias\E \. ([^\.]+) $ /x) { + $colmap->{$_} = $1; + } + elsif ($_ !~ /\./) { + $colmap->{"$alias.$_"} = $_; + $colmap->{$_} = $_; + } + } + + 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 + 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_rs; + $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 $new_attrs->{prefetch} ); + + # {collapse} would mean a has_many join was injected, which in turn means + # we need to group *IF WE CAN* (only if the column in question is unique) + if (!$orig_attrs->{group_by} && $orig_attrs->{collapse}) { + + if ($colmap->{$select} and $rsrc->_identifying_column_set([$colmap->{$select}])) { + $new_attrs->{group_by} = [ $select ]; + delete @{$new_attrs}{qw(distinct _grouped_by_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.' + ); + } + } + + return bless { + _select => $select, + _as => $column, + _parent_resultset => $new_parent_rs + }, $class; } +=head2 as_query + +=over 4 + +=item Arguments: none + +=item Return Value: \[ $sql, L<@bind_values|DBIx::Class::ResultSet/DBIC BIND VALUES> ] + +=back + +Returns the SQL query and bind vars associated with the invocant. + +This is generally used as the RHS for a subquery. + +=cut + +sub as_query { return shift->_resultset->as_query(@_) } + =head2 next =over 4 @@ -57,16 +145,17 @@ sub new { 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; - - $self->{_resultset} = $self->{_parent_resultset}->search(undef, {select => [$self->{_column}], as => [$self->{_column}]}) unless ($self->{_resultset}); - my ($row) = $self->{_resultset}->cursor->next; + + # using cursor so we don't inflate anything + my ($row) = $self->_resultset->cursor->next; + return $row; } @@ -84,13 +173,92 @@ Returns all values of the column in the resultset (or C if there are none). Much like L but returns values rather -than row objects. +than result objects. =cut sub all { my $self = shift; - return map {$_->[0]} $self->{_parent_resultset}->search(undef, {select => [$self->{_column}], as => [$self->{_column}]})->cursor->all; + + # using cursor so we don't inflate anything + return map { $_->[0] } $self->_resultset->cursor->all; +} + +=head2 reset + +=over 4 + +=item Arguments: none + +=item Return Value: $self + +=back + +Resets the underlying resultset's cursor, so you can iterate through the +elements of the column again. + +Much like L. + +=cut + +sub reset { + my $self = shift; + $self->_resultset->cursor->reset; + return $self; +} + +=head2 first + +=over 4 + +=item Arguments: none + +=item Return Value: $value + +=back + +Resets the underlying resultset and returns the next value of the column in the +resultset (or C if there is none). + +Much like L but just returning the one value. + +=cut + +sub first { + my $self = shift; + + # 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->schema->storage->select_single( + $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs + ); + + return $row; } =head2 min @@ -110,9 +278,30 @@ resultset (or C if there are none). =cut -sub min { - my $self = shift; - return $self->func('MIN'); +sub min :DBIC_method_is_indirect_sugar { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call; + $_[0]->func('MIN'); +} + +=head2 min_rs + +=over 4 + +=item Arguments: none + +=item Return Value: L<$resultset|DBIx::Class::ResultSet> + +=back + + my $rs = $year_col->min_rs(); + +Wrapper for ->func_rs for function MIN(). + +=cut + +sub min_rs :DBIC_method_is_indirect_sugar { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call; + $_[0]->func_rs('MIN') } =head2 max @@ -132,9 +321,30 @@ resultset (or C if there are none). =cut -sub max { - my $self = shift; - return $self->func('MAX'); +sub max :DBIC_method_is_indirect_sugar { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call; + $_[0]->func('MAX'); +} + +=head2 max_rs + +=over 4 + +=item Arguments: none + +=item Return Value: L<$resultset|DBIx::Class::ResultSet> + +=back + + my $rs = $year_col->max_rs(); + +Wrapper for ->func_rs for function MAX(). + +=cut + +sub max_rs :DBIC_method_is_indirect_sugar { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call; + $_[0]->func_rs('MAX') } =head2 sum @@ -154,9 +364,30 @@ the resultset. Use on varchar-like columns at your own risk. =cut -sub sum { - my $self = shift; - return $self->func('SUM'); +sub sum :DBIC_method_is_indirect_sugar { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call; + $_[0]->func('SUM'); +} + +=head2 sum_rs + +=over 4 + +=item Arguments: none + +=item Return Value: L<$resultset|DBIx::Class::ResultSet> + +=back + + my $rs = $year_col->sum_rs(); + +Wrapper for ->func_rs for function SUM(). + +=cut + +sub sum_rs :DBIC_method_is_indirect_sugar { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call; + $_[0]->func_rs('SUM') } =head2 func @@ -180,23 +411,134 @@ value. Produces the following SQL: =cut sub func { + my ($self,$function) = @_; + my $cursor = $self->func_rs($function)->cursor; + + if( wantarray ) { + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_WANTARRAY and my $sog = fail_on_internal_wantarray; + return map { $_->[ 0 ] } $cursor->all; + } + + return ( $cursor->next )[ 0 ]; +} + +=head2 func_rs + +=over 4 + +=item Arguments: $function + +=item Return Value: L<$resultset|DBIx::Class::ResultSet> + +=back + +Creates the resultset that C uses to run its query. + +=cut + +sub func_rs { + my ($self,$function) = @_; + + my $rs = $self->{_parent_resultset}; + my $select = $self->{_select}; + + # wrap a grouped rs + if ($rs->_resolved_attrs->{group_by}) { + $select = $self->{_as}; + $rs = $rs->as_subselect_rs; + } + + # FIXME - remove at some point in the future (2018-ish) + wantarray + and + carp_unique( + 'Starting with DBIC@0.082900 func_rs() always returns a ResultSet ' + . 'instance regardless of calling context. Please force scalar() context to ' + . 'silence this warning' + ) + and + DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_WANTARRAY + and + my $sog = fail_on_internal_wantarray + ; + + $rs->search_rs( undef, { + columns => { $self->{_as} => { $function => $select } } + } ); +} + +=head2 throw_exception + +See L for details. + +=cut + +sub throw_exception { my $self = shift; - my $function = shift; - my ($row) = $self->{_parent_resultset}->search(undef, {select => {$function => $self->{_column}}, as => [$self->{_column}]})->cursor->next; - return $row; + if (ref $self && $self->{_parent_resultset}) { + $self->{_parent_resultset}->throw_exception(@_); + } + else { + DBIx::Class::Exception->throw(@_); + } } -1; +# _resultset +# +# Arguments: none +# +# Return Value: $resultset +# +# $year_col->_resultset->next +# +# Returns the underlying resultset. Creates it from the parent resultset if +# necessary. +# +sub _resultset { + my $self = shift; -=head1 AUTHORS + return $self->{_resultset} ||= do { + + my $select = $self->{_select}; + + if ($self->{_parent_resultset}{attrs}{distinct}) { + my $alias = $self->{_parent_resultset}->current_source_alias; + my $rsrc = $self->{_parent_resultset}->result_source; + my %cols = map { $_ => 1, "$alias.$_" => 1 } $rsrc->columns; + + unless( $cols{$select} ) { + carp_unique( + 'Use of distinct => 1 while selecting anything other than a column ' + . 'declared on the primary ResultSource is deprecated (you selected ' + . "'$self->{_as}') - please supply an explicit group_by instead" + ); + + # collapse the selector to a literal so that it survives the distinct parse + # if it turns out to be an aggregate - at least the user will get a proper exception + # instead of silent drop of the group_by altogether + $select = \[ $rsrc->schema->storage->sql_maker->_recurse_fields($select) ]; + } + } + + $self->{_parent_resultset}->search(undef, { + columns => { $self->{_as} => $select } + }); + }; +} -Luke Saunders +=head1 FURTHER QUESTIONS? -Jess Robinson +Check the list of L. -=head1 LICENSE +=head1 COPYRIGHT AND LICENSE -You may distribute this code under the same terms as Perl itself. +This module is free software L +by the L. You can +redistribute it and/or modify it under the same terms as the +L. =cut + +1; +