X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FDBIx%2FClass%2FResultSet.pm;h=a2f95f11b81991017f83ede991ba65a1d7cddea1;hb=908aa1bb761ec1da5c061fe9f687598e3f1934bc;hp=d8835510087872c96a6ed49a7eeec88fe31dfc59;hpb=8bc474676193d8832932f01cc60f85e7c1d44c76;p=dbsrgits%2FDBIx-Class.git diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm index d883551..a2f95f1 100644 --- a/lib/DBIx/Class/ResultSet.pm +++ b/lib/DBIx/Class/ResultSet.pm @@ -74,6 +74,34 @@ However, if it is used in a boolean context it is B true. So if you want to check if a resultset has any results, you must use C. +=head1 CUSTOM ResultSet CLASSES THAT USE Moose + +If you want to make your custom ResultSet classes with L, use a template +similar to: + + package MyApp::Schema::ResultSet::User; + + use Moose; + use namespace::autoclean; + use MooseX::NonMoose; + extends 'DBIx::Class::ResultSet'; + + sub BUILDARGS { $_[2] } + + ...your code... + + __PACKAGE__->meta->make_immutable; + + 1; + +The L is necessary so that the L constructor does not +clash with the regular ResultSet constructor. Alternatively, you can use: + + __PACKAGE__->meta->make_immutable(inline_constructor => 0); + +The L is necessary because the +signature of the ResultSet C is C<< ->new($source, \%args) >>. + =head1 EXAMPLES =head2 Chaining resultsets @@ -265,7 +293,7 @@ condition-bound methods L, L and L. The user must ensure manually that any value passed to this method will stringify to something the RDBMS knows how to deal with. A notable example is the handling of L objects, for more info see: -L. +L. =cut @@ -446,7 +474,7 @@ sub _normalize_selection { $attrs->{'+columns'} = $self->_merge_attr($attrs->{'+columns'}, delete $attrs->{include_columns}) if exists $attrs->{include_columns}; - # columns are always placed first, however + # columns are always placed first, however # Keep the X vs +X separation until _resolved_attrs time - this allows to # delay the decision on whether to use a default select list ($rsrc->columns) @@ -801,7 +829,7 @@ sub find { # Run the query, passing the result_class since it should propagate for find my $rs = $self->search ($final_cond, {result_class => $self->result_class, %$attrs}); - if (keys %{$rs->_resolved_attrs->{collapse}}) { + if ($rs->_resolved_attrs->{collapse}) { my $row = $rs->next; carp "Query returned more than one row" if $rs->next; return $row; @@ -899,7 +927,7 @@ sub _build_unique_cond { =over 4 -=item Arguments: $rel, $cond, \%attrs? +=item Arguments: $rel, $cond?, \%attrs? =item Return Value: $new_resultset (scalar context) || @row_objs (list context) @@ -1010,11 +1038,9 @@ sub single { my $attrs = $self->_resolved_attrs_copy; - if (keys %{$attrs->{collapse}}) { - $self->throw_exception( - 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead' - ); - } + $self->throw_exception( + 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead' + ) if $attrs->{collapse}; if ($where) { if (defined $attrs->{where}) { @@ -1028,12 +1054,12 @@ sub single { } } - my @data = $self->result_source->storage->select_single( + my $data = [ $self->result_source->storage->select_single( $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs - ); + )]; - return (@data ? ($self->_construct_object(@data))[0] : undef); + return @$data ? $self->_construct_objects($data)->[0] : undef; } @@ -1190,161 +1216,117 @@ first record from the resultset. sub next { my ($self) = @_; + if (my $cache = $self->get_cache) { $self->{all_cache_position} ||= 0; return $cache->[$self->{all_cache_position}++]; } + if ($self->{attrs}{cache}) { delete $self->{pager}; $self->{all_cache_position} = 1; return ($self->all)[0]; } - if ($self->{stashed_objects}) { - my $obj = shift(@{$self->{stashed_objects}}); - delete $self->{stashed_objects} unless @{$self->{stashed_objects}}; - return $obj; - } - my @row = ( - exists $self->{stashed_row} - ? @{delete $self->{stashed_row}} - : $self->cursor->next - ); - return undef unless (@row); - my ($row, @more) = $self->_construct_object(@row); - $self->{stashed_objects} = \@more if @more; - return $row; -} - -sub _construct_object { - my ($self, @row) = @_; - - my $info = $self->_collapse_result($self->{_attrs}{as}, \@row) - or return (); - 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_proto, $row) = @_; + return shift(@{$self->{stashed_objects}}) if @{ $self->{stashed_objects}||[] }; - my @copy = @$row; + $self->{stashed_objects} = $self->_construct_objects + or return undef; - # 'foo' => [ undef, 'foo' ] - # 'foo.bar' => [ 'foo', 'bar' ] - # 'foo.bar.baz' => [ 'foo.bar', 'baz' ] - - my @construct_as = map { [ (/^(?:(.*)\.)?([^.]+)$/) ] } @$as_proto; - - my %collapse = %{$self->{_attrs}{collapse}||{}}; - - my @pri_index; - - # if we're doing collapsing (has_many prefetch) we need to grab records - # until the PK changes, so fill @pri_index. if not, we leave it empty so - # we know we don't have to bother. - - # the reason for not using the collapse stuff directly is because if you - # had for e.g. two artists in a row with no cds, the collapse info for - # both would be NULL (undef) so you'd lose the second artist + return shift @{$self->{stashed_objects}}; +} - # store just the index so we can check the array positions from the row - # without having to contruct the full hash +# takes a single DBI-row of data and coinstructs as many objects +# as the resultset attributes call for. +# This can be a bit of an action at a distance - it takes as an argument +# the *current* cursor-row (already taken off the $sth), but if +# collapsing is requested it will keep advancing the cursor either +# until the current row-object is assembled (the collapser was able to +# order the result sensibly) OR until the cursor is exhausted (an +# unordered collapsing resultset effectively triggers ->all) +sub _construct_objects { + my ($self, $fetched_row, $fetch_all) = @_; - if (keys %collapse) { - my %pri = map { ($_ => 1) } $self->result_source->_pri_cols; - foreach my $i (0 .. $#construct_as) { - next if defined($construct_as[$i][0]); # only self table - if (delete $pri{$construct_as[$i][1]}) { - push(@pri_index, $i); - } - last unless keys %pri; # short circuit (Johnny Five Is Alive!) - } + my $attrs = $self->_resolved_attrs; + my $unordered = 0; # will deal with this later + + # this will be used as both initial raw-row collector AND as a RV of + # _construct_objects. Not regrowing the # array twice matters a lot... + # a suprising amount actually + my $rows; + + # $fetch_all implies all() which means all stashes have been cleared + # and the cursor reset + if ($fetch_all) { + # FIXME - we can do better, cursor->all (well a diff. method) should return a ref + $rows = [ $self->cursor->all ]; + } + elsif ($unordered) { + $rows = [ + $fetched_row||(), + @{ delete $self->{stashed_rows} || []}, + $self->cursor->all, + ]; + } + else { # simple single object + $rows = [ $fetched_row || ( @{$self->{stashed_rows}||[]} ? shift @{$self->{stashed_rows}} : [$self->cursor->next] ) ]; } - # no need to do an if, it'll be empty if @pri_index is empty anyway - - my %pri_vals = map { ($_ => $copy[$_]) } @pri_index; - - my @const_rows; - - do { # no need to check anything at the front, we always want the first row - - my %const; + return undef unless @{$rows->[0]||[]}; - foreach my $this_as (@construct_as) { - $const{$this_as->[0]||''}{$this_as->[1]} = shift(@copy); + my $rsrc = $self->result_source; + my $res_class = $self->result_class; + my $inflator = $res_class->can ('inflate_result') + or $self->throw_exception("Inflator $res_class does not provide an inflate_result() method"); + + # construct a much simpler array->hash folder for the one-table cases right here + if ($attrs->{_single_object_inflation} and ! $attrs->{collapse}) { + # FIXME this is a very very very hot spot + # while rather optimal we can *still* do much better, by + # building a smarter [Row|HRI]::inflate_result(), and + # switch to feeding it data via some leaner interface + # + my $infmap = $attrs->{as}; + my @as_idx = 0..$#$infmap; + for my $r (@$rows) { + $r = [{ map { $infmap->[$_] => $r->[$_] } @as_idx }] } - push(@const_rows, \%const); - - } until ( # no pri_index => no collapse => drop straight out - !@pri_index - or - do { # get another row, stash it, drop out if different PK - - @copy = $self->cursor->next; - $self->{stashed_row} = \@copy; - - # last thing in do block, counts as true if anything doesn't match - - # check xor defined first for NULL vs. NOT NULL then if one is - # defined the other must be so check string equality - - grep { - (defined $pri_vals{$_} ^ defined $copy[$_]) - || (defined $pri_vals{$_} && ($pri_vals{$_} ne $copy[$_])) - } @pri_index; - } - ); - - my $alias = $self->{attrs}{alias}; - my $info = []; - - my %collapse_pos; + # FIXME - this seems to be faster than the hashmapper aove, especially + # on more rows, but need a better bench-environment to confirm + #eval sprintf ( + # '$_ = [{ %s }] for @$rows', + # join (', ', map { "\$infmap->[$_] => \$_->[$_]" } 0..$#$infmap ) + #); + } + else { + push @$rows, @{$self->{stashed_rows}||[]}; + + $rsrc->_mk_row_parser({ + inflate_map => $attrs->{as}, + selection => $attrs->{select}, + collapse => $attrs->{collapse}, + unordered => $unordered, + })->( + $rows, # modify in-place, shrinking/extending as necessary + ($attrs->{collapse} and ! $fetch_all and ! $unordered) + ? ( + sub { my @r = $self->cursor->next or return undef; \@r }, + ($self->{stashed_rows} = []), # this is where we empty things and prepare for leftovers + ) + : () + , + ); + } - my @const_keys; + $_ = $res_class->$inflator($rsrc, @$_) for @$rows; - foreach my $const (@const_rows) { - scalar @const_keys or do { - @const_keys = sort { length($a) <=> length($b) } keys %$const; - }; - foreach my $key (@const_keys) { - if (length $key) { - my $target = $info; - my @parts = split(/\./, $key); - my $cur = ''; - my $data = $const->{$key}; - foreach my $p (@parts) { - $target = $target->[1]->{$p} ||= []; - $cur .= ".${p}"; - if ($cur eq ".${key}" && (my @ckey = @{$collapse{$cur}||[]})) { - # collapsing at this point and on final part - my $pos = $collapse_pos{$cur}; - CK: foreach my $ck (@ckey) { - if (!defined $pos->{$ck} || $pos->{$ck} ne $data->{$ck}) { - $collapse_pos{$cur} = $data; - delete @collapse_pos{ # clear all positioning for sub-entries - grep { m/^\Q${cur}.\E/ } keys %collapse_pos - }; - push(@$target, []); - last CK; - } - } - } - if (exists $collapse{$cur}) { - $target = $target->[-1]; - } - } - $target->[0] = $data; - } else { - $info->[0] = $const->{$key}; - } - } + # CDBI compat stuff + if ($attrs->{record_filter}) { + $_ = $attrs->{record_filter}->($_) for @$rows; } - return $info; + return $rows; } =head2 result_source @@ -1513,10 +1495,15 @@ sub _count_subq_rs { # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/}; - # if we multi-prefetch we group_by primary keys only as this is what we would + # if we multi-prefetch we group_by something unique, as this is what we would # get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless - if ( keys %{$attrs->{collapse}} ) { - $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->_pri_cols) ] + if ( $attrs->{collapse} ) { + $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } @{ + $rsrc->_identifying_column_set || $self->throw_exception( + 'Unable to construct a unique group_by criteria properly collapsing the ' + . 'has_many prefetch before count()' + ); + } ] } # Calculate subquery selector @@ -1627,33 +1614,23 @@ Returns all elements in the resultset. sub all { my $self = shift; if(@_) { - $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()"); + $self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()"); } - return @{ $self->get_cache } if $self->get_cache; - - my @obj; - - if (keys %{$self->_resolved_attrs->{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; + delete $self->{stashed_rows}; + delete $self->{stashed_objects}; + + if (my $c = $self->get_cache) { + return @$c; } - $self->set_cache(\@obj) if $self->{attrs}{cache}; + $self->cursor->reset; + + my $objs = $self->_construct_objects(undef, 'fetch_all') || []; - return @obj; + $self->set_cache($objs) if $self->{attrs}{cache}; + + return @$objs; } =head2 reset @@ -1674,7 +1651,10 @@ another query. sub reset { my ($self) = @_; - delete $self->{_attrs} if exists $self->{_attrs}; + delete $self->{_attrs}; + delete $self->{stashed_rows}; + delete $self->{stashed_objects}; + $self->{all_cache_position} = 0; $self->cursor->reset; return $self; @@ -1709,35 +1689,122 @@ sub first { sub _rs_update_delete { my ($self, $op, $values) = @_; + my $cond = $self->{cond}; my $rsrc = $self->result_source; + my $storage = $rsrc->schema->storage; + + my $attrs = { %{$self->_resolved_attrs} }; + + # "needs" is a strong word here - if the subquery is part of an IN clause - no point of + # even adding the group_by. It will really be used only when composing a poor-man's + # multicolumn-IN equivalent OR set + my $needs_group_by_subq = defined $attrs->{group_by}; + + # simplify the joinmap and maybe decide if a grouping (and thus subquery) is necessary + my $relation_classifications; + if (ref($attrs->{from}) eq 'ARRAY') { + $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $cond, $attrs); + + $relation_classifications = $storage->_resolve_aliastypes_from_select_args ( + [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ], + $attrs->{select}, + $cond, + $attrs + ) unless $needs_group_by_subq; # we already know we need a group, no point of resolving them + } + else { + $needs_group_by_subq ||= 1; # if {from} is unparseable assume the worst + } - my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/); - my $needs_subq = $needs_group_by_subq || $self->_has_resolved_attr(qw/rows offset/); + $needs_group_by_subq ||= exists $relation_classifications->{multiplying}; - if ($needs_group_by_subq or $needs_subq) { + # if no subquery - life is easy-ish + unless ( + $needs_group_by_subq + or + keys %$relation_classifications # if any joins at all - need to wrap a subq + or + $self->_has_resolved_attr(qw/rows offset/) # limits call for a subq + ) { + # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus + # a condition containing 'me' or other table prefixes will not work + # at all. What this code tries to do (badly) is to generate a condition + # with the qualifiers removed, by exploiting the quote mechanism of sqla + # + # this is atrocious and should be replaced by normal sqla introspection + # one sunny day + my ($sql, @bind) = do { + my $sqla = $rsrc->storage->sql_maker; + local $sqla->{_dequalify_idents} = 1; + $sqla->_recurse_where($self->{cond}); + } if $self->{cond}; - # make a new $rs selecting only the PKs (that's all we really need) - my $attrs = $self->_resolved_attrs_copy; + return $rsrc->storage->$op( + $rsrc, + $op eq 'update' ? $values : (), + $self->{cond} ? \[$sql, @bind] : (), + ); + } + + # we got this far - means it is time to wrap a subquery + my $idcols = $rsrc->_identifying_column_set || $self->throw_exception( + sprintf( + "Unable to perform complex resultset %s() without an identifying set of columns on source '%s'", + $op, + $rsrc->source_name, + ) + ); + my $existing_group_by = delete $attrs->{group_by}; + # make a new $rs selecting only the PKs (that's all we really need for the subq) + delete $attrs->{$_} for qw/collapse select _prefetch_selector_range as/; + $attrs->{columns} = [ map { "$attrs->{alias}.$_" } @$idcols ]; + $attrs->{group_by} = \ ''; # FIXME - this is an evil hack, it causes the optimiser to kick in and throw away the LEFT joins + my $subrs = (ref $self)->new($rsrc, $attrs); - delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_selector_range as/; - $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ]; + if (@$idcols == 1) { + return $storage->$op ( + $rsrc, + $op eq 'update' ? $values : (), + { $idcols->[0] => { -in => $subrs->as_query } }, + ); + } + elsif ($storage->_use_multicolumn_in) { + # This is hideously ugly, but SQLA does not understand multicol IN expressions + my $sql_maker = $storage->sql_maker; + my ($sql, @bind) = @${$subrs->as_query}; + $sql = sprintf ('(%s) IN %s', # the as_query already comes with a set of parenthesis + join (', ', map { $sql_maker->_quote ($_) } @$idcols), + $sql, + ); + return $storage->$op ( + $rsrc, + $op eq 'update' ? $values : (), + \[$sql, @bind], + ); + } + else { + # if all else fails - get all primary keys and operate over a ORed set + # wrap in a transaction for consistency + # this is where the group_by starts to matter + my $subq_group_by; if ($needs_group_by_subq) { - # make sure no group_by was supplied, or if there is one - make sure it matches - # the columns compiled above perfectly. Anything else can not be sanely executed - # on most databases so croak right then and there + $subq_group_by = $attrs->{columns}; - if (my $g = $attrs->{group_by}) { + # make sure if there is a supplied group_by it matches the columns compiled above + # perfectly. Anything else can not be sanely executed on most databases so croak + # right then and there + if ($existing_group_by) { my @current_group_by = map { $_ =~ /\./ ? $_ : "$attrs->{alias}.$_" } - @$g + @$existing_group_by ; if ( join ("\x00", sort @current_group_by) ne - join ("\x00", sort @{$attrs->{columns}} ) + join ("\x00", sort @$subq_group_by ) ) { $self->throw_exception ( "You have just attempted a $op operation on a resultset which does group_by" @@ -1748,33 +1815,27 @@ sub _rs_update_delete { ); } } - else { - $attrs->{group_by} = $attrs->{columns}; - } } - my $subrs = (ref $self)->new($rsrc, $attrs); - return $self->result_source->storage->_subq_update_delete($subrs, $op, $values); - } - else { - # Most databases do not allow aliasing of tables in UPDATE/DELETE. Thus - # a condition containing 'me' or other table prefixes will not work - # at all. What this code tries to do (badly) is to generate a condition - # with the qualifiers removed, by exploiting the quote mechanism of sqla - # - # this is atrocious and should be replaced by normal sqla introspection - # one sunny day - my ($sql, @bind) = do { - my $sqla = $rsrc->storage->sql_maker; - local $sqla->{_dequalify_idents} = 1; - $sqla->_recurse_where($self->{cond}); - } if $self->{cond}; + my $guard = $storage->txn_scope_guard; - return $rsrc->storage->$op( + my @op_condition; + for my $row ($subrs->search({}, { group_by => $subq_group_by })->cursor->all) { + push @op_condition, { map + { $idcols->[$_] => $row->[$_] } + (0 .. $#$idcols) + }; + } + + my $res = $storage->$op ( $rsrc, $op eq 'update' ? $values : (), - $self->{cond} ? \[$sql, @bind] : (), + \@op_condition, ); + + $guard->commit; + + return $res; } } @@ -1794,7 +1855,7 @@ triggers, nor will it update any row object instances derived from this resultset (this includes the contents of the L if any). See L if you need to execute any on-update triggers or cascades defined either by you or a -L. +L. The return value is a pass through of what the underlying storage backend returned, and may vary. See L for the most @@ -1807,7 +1868,7 @@ This is unlike the corresponding L. The user must ensure manually that any value passed to this method will stringify to something the RDBMS knows how to deal with. A notable example is the handling of L objects, for more info see: -L. +L. =cut @@ -1862,7 +1923,7 @@ L status of any row object instances derived from this resultset (this includes the contents of the L if any). See L if you need to execute any on-delete triggers or cascades defined either by you or a -L. +L. The return value is a pass through of what the underlying storage backend returned, and may vary. See L for the most common case. @@ -1991,7 +2052,7 @@ sub populate { push(@created, $self->create($item)); } return wantarray ? @created : \@created; - } + } else { my $first = $data->[0]; @@ -2598,6 +2659,23 @@ all in the call to C, even when set to C. See also L and L. For information on how to declare unique constraints, see L. +If you need to know if an existing row was found or a new one created use +L and L instead. Don't forget +to call L to save the newly created row to the +database! + + my $cd = $schema->resultset('CD')->find_or_new({ + cdid => 5, + artist => 'Massive Attack', + title => 'Mezzanine', + year => 2005, + }); + + if( $cd->in_storage ) { + # do some stuff + $cd->insert; + } + =cut sub find_or_create { @@ -2659,6 +2737,25 @@ all in the call to C, even when set to C. See also L and L. For information on how to declare unique constraints, see L. +If you need to know if an existing row was updated or a new one created use +L and L instead. Don't forget +to call L to save the newly created row to the +database! + + my $cd = $schema->resultset('CD')->update_or_new( + { + artist => 'Massive Attack', + title => 'Mezzanine', + year => 1998, + }, + { key => 'cd_artist_title' } + ); + + if( $cd->in_storage ) { + # do some stuff + $cd->insert; + } + =cut sub update_or_create { @@ -2720,7 +2817,7 @@ supplied by the database (e.g. an auto_increment primary key column). In normal usage, the value of such columns should NOT be included at all in the call to C, even when set to C. -See also L, L and L. +See also L, L and L. =cut @@ -2888,7 +2985,7 @@ sub related_resultset { if (my $cache = $self->get_cache) { if ($cache->[0] && $cache->[0]->related_resultset($rel)->get_cache) { - $new_cache = [ map { @{$_->related_resultset($rel)->get_cache} } + $new_cache = [ map { @{$_->related_resultset($rel)->get_cache||[]} } @$cache ]; } } @@ -2948,9 +3045,9 @@ source alias of the current result set: my $me = $self->current_source_alias; - return $self->search( + return $self->search({ "$me.modified" => $user->id, - ); + }); } =cut @@ -3191,14 +3288,10 @@ sub _resolved_attrs { if $attrs->{select}; # assume all unqualified selectors to apply to the current alias (legacy stuff) - for (@sel) { - $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_"; - } + $_ = (ref $_ or $_ =~ /\./) ? $_ : "$alias.$_" for @sel; - # disqualify all $alias.col as-bits (collapser mandated) - for (@as) { - $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_; - } + # disqualify all $alias.col as-bits (inflate-map mandated) + $_ = ($_ =~ /^\Q$alias.\E(.+)$/) ? $1 : $_ for @as; # de-duplicate the result (remove *identical* select/as pairs) # and also die on duplicate {as} pointing to different {select}s @@ -3285,15 +3378,17 @@ sub _resolved_attrs { } } - $attrs->{collapse} ||= {}; - if ($attrs->{prefetch}) { + # generate selections based on the prefetch helper + my $prefetch; + $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} ) + if defined $attrs->{prefetch}; + + if ($prefetch) { $self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}") if $attrs->{_dark_selector}; - my $prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} ); - - my $prefetch_ordering = []; + $attrs->{collapse} = 1; # this is a separate structure (we don't look in {from} directly) # as the resolver needs to shift things off the lists to work @@ -3316,8 +3411,7 @@ sub _resolved_attrs { } } - my @prefetch = - $source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} ); + my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map ); # we need to somehow mark which columns came from prefetch if (@prefetch) { @@ -3327,11 +3421,34 @@ sub _resolved_attrs { push @{ $attrs->{select} }, (map { $_->[0] } @prefetch); push @{ $attrs->{as} }, (map { $_->[1] } @prefetch); + } + + # run through the resulting joinstructure (starting from our current slot) + # and unset collapse if proven unnesessary + if ($attrs->{collapse} && ref $attrs->{from} eq 'ARRAY') { + + if (@{$attrs->{from}} > 1) { - push( @{$attrs->{order_by}}, @$prefetch_ordering ); - $attrs->{_collapse_order_by} = \@$prefetch_ordering; + # find where our table-spec starts and consider only things after us + my @fromlist = @{$attrs->{from}}; + while (@fromlist) { + my $t = shift @fromlist; + $t = $t->[0] if ref $t eq 'ARRAY'; #me vs join from-spec mismatch + last if ($t->{-alias} && $t->{-alias} eq $alias); + } + + for (@fromlist) { + $attrs->{collapse} = ! $_->[0]{-is_single} + and last; + } + } + else { + # no joins - no collapse + $attrs->{collapse} = 0; + } } + $attrs->{_single_object_inflation} = ! List::Util::first { $_ =~ /\./ } @{$attrs->{as}}; # if both page and offset are specified, produce a combined offset # even though it doesn't make much sense, this is what pre 081xx has @@ -4081,6 +4198,24 @@ rows per page if the page attribute or method is used. Specifies the (zero-based) row number for the first row to be returned, or the of the first row of the first page if paging is used. +=head2 software_limit + +=over 4 + +=item Value: (0 | 1) + +=back + +When combined with L and/or L the generated SQL will not +include any limit dialect stanzas. Instead the entire result will be selected +as if no limits were specified, and DBIC will perform the limit locally, by +artificially advancing and finishing the resulting L. + +This is the recommended way of performing resultset limiting when no sane RDBMS +implementation is available (e.g. +L using the +L hack) + =head2 group_by =over 4 @@ -4134,6 +4269,8 @@ Adds to the WHERE clause. Can be overridden by passing C<< { where => undef } >> as an attribute to a resultset. +For more complicated where clauses see L. + =back =head2 cache