use strict;
use warnings;
-use overload
- '0+' => "count",
- 'bool' => "_bool",
- fallback => 1;
+use base qw/DBIx::Class/;
use Carp::Clan qw/^DBIx::Class/;
use DBIx::Class::Exception;
use Data::Page;
use DBIx::Class::ResultSetColumn;
use DBIx::Class::ResultSourceHandle;
use List::Util ();
-use Scalar::Util ();
-use base qw/DBIx::Class/;
+use Scalar::Util qw/blessed weaken/;
+use Try::Tiny;
+use namespace::clean;
+
+use overload
+ '0+' => "count",
+ 'bool' => "_bool",
+ fallback => 1;
__PACKAGE__->mk_group_accessors('simple' => qw/_result_class _source_handle/);
The query that the ResultSet represents is B<only> executed against
the database when these methods are called:
-L</find> L</next> L</all> L</first> L</single> L</count>
+L</find>, L</next>, L</all>, L</first>, L</single>, L</count>.
+
+If a resultset is used in a numeric context it returns the L</count>.
+However, if it is used in a boolean context it is B<always> true. So if
+you want to check if a resultset has any results, you must use C<if $rs
+!= 0>.
=head1 EXAMPLES
L</join>, L</prefetch>, L</+select>, L</+as> attributes are merged
into the existing ones from the original resultset.
-The L</where>, L</having> attribute, and any search conditions are
+The L</where> and L</having> attributes, and any search conditions, are
merged with an SQL C<AND> to the existing condition from the original
resultset.
See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
-=head1 OVERLOADING
-
-If a resultset is used in a numeric context it returns the L</count>.
-However, if it is used in a boolean context it is always true. So if
-you want to check if a resultset has any results use C<if $rs != 0>.
-C<if $rs> will always be true.
-
=head1 METHODS
=head2 new
my $self = {
_source_handle => $source,
cond => $attrs->{where},
- count => undef,
pager => undef,
attrs => $attrs
};
: $self->_add_alias($input_query, $alias);
}
- # Run the query
- my $rs = $self->search ($query, $attrs);
+ # Run the query, passing the result_class since it should propagate for find
+ my $rs = $self->search ($query, {result_class => $self->result_class, %$attrs});
if (keys %{$rs->_resolved_attrs->{collapse}}) {
my $row = $rs->next;
carp "Query returned more than one row" if $rs->next;
=item Arguments: $cond?
-=item Return Value: $row_object?
+=item Return Value: $row_object | undef
=back
my $cd = $schema->resultset('CD')->single({ year => 2001 });
Inflates the first result without creating a cursor if the resultset has
-any records in it; if not returns nothing. Used by L</find> as a lean version of
-L</search>.
+any records in it; if not returns C<undef>. Used by L</find> as a lean version
+of L</search>.
While this method can take an optional search condition (just like L</search>)
being a fast-code-path it does not recognize search attributes. If you need to
$attrs->{offset} = $self->{attrs}{offset} || 0;
$attrs->{offset} += $min;
$attrs->{rows} = ($max ? ($max - $min + 1) : 1);
- return $self->search(undef(), $attrs);
+ return $self->search(undef, $attrs);
#my $slice = (ref $self)->new($self->result_source, $attrs);
#return (wantarray ? $slice->all : $slice);
}
=item Arguments: none
-=item Return Value: $result?
+=item Return Value: $result | undef
=back
return $cache->[$self->{all_cache_position}++];
}
if ($self->{attrs}{cache}) {
+ delete $self->{pager};
$self->{all_cache_position} = 1;
return ($self->all)[0];
}
my $rsrc = $self->result_source;
$attrs ||= $self->_resolved_attrs;
- # only take pieces we need for a simple count
- my $tmp_attrs = { map
- { $_ => $attrs->{$_} }
- qw/ alias from where bind join /
- };
+ my $tmp_attrs = { %$attrs };
+ # take off any limits, record_filter is cdbi, and no point of ordering nor locking a count
+ delete @{$tmp_attrs}{qw/rows offset order_by record_filter for/};
# overwrite the selector (supplied by the storage)
- $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $tmp_attrs);
+ $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $attrs);
$tmp_attrs->{as} = 'count';
my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
my $rsrc = $self->result_source;
$attrs ||= $self->_resolved_attrs;
- my $sub_attrs = { map
- { $_ => $attrs->{$_} }
- qw/ alias from where bind join group_by having rows offset /
- };
+ my $sub_attrs = { %$attrs };
+ # extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
+ delete @{$sub_attrs}{qw/collapse select _prefetch_select as order_by for/};
# if we multi-prefetch we group_by primary keys only as this is what we would
# get out of the rs via ->next/->all. We *DO WANT* to clobber old group_by regardless
# Calculate subquery selector
if (my $g = $sub_attrs->{group_by}) {
+ my $sql_maker = $rsrc->storage->sql_maker;
+
# necessary as the group_by may refer to aliased functions
my $sel_index;
for my $sel (@{$attrs->{select}}) {
}
for my $g_part (@$g) {
- push @{$sub_attrs->{select}}, $sel_index->{$g_part} || $g_part;
+ my $colpiece = $sel_index->{$g_part} || $g_part;
+
+ # disqualify join-based group_by's. Arcane but possible query
+ # also horrible horrible hack to alias a column (not a func.)
+ # (probably need to introduce SQLA syntax)
+ if ($colpiece =~ /\./ && $colpiece !~ /^$attrs->{alias}\./) {
+ my $as = $colpiece;
+ $as =~ s/\./__/;
+ $colpiece = \ sprintf ('%s AS %s', map { $sql_maker->_quote ($_) } ($colpiece, $as) );
+ }
+ push @{$sub_attrs->{select}}, $colpiece;
}
}
else {
->new ($rsrc, $sub_attrs)
->as_subselect_rs
->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
- -> get_column ('count');
+ ->get_column ('count');
}
sub _bool {
=item Arguments: none
-=item Return Value: $object?
+=item Return Value: $object | undef
=back
-Resets the resultset and returns an object for the first result (if the
-resultset returns anything).
+Resets the resultset and returns an object for the first result (or C<undef>
+if the resultset is empty).
=cut
# make a new $rs selecting only the PKs (that's all we really need)
my $attrs = $self->_resolved_attrs_copy;
- delete $attrs->{$_} for qw/collapse select as/;
+
+ delete $attrs->{$_} for qw/collapse _collapse_order_by select _prefetch_select as/;
$attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ];
if ($needs_group_by_subq) {
}
my $subrs = (ref $self)->new($rsrc, $attrs);
-
return $self->result_source->storage->_subq_update_delete($subrs, $op, $values);
}
else {
=cut
+# make a wizard good for both a scalar and a hashref
+my $mk_lazy_count_wizard = sub {
+ require Variable::Magic;
+
+ my $stash = { total_rs => shift };
+ my $slot = shift; # only used by the hashref magic
+
+ my $magic = Variable::Magic::wizard (
+ data => sub { $stash },
+
+ (!$slot)
+ ? (
+ # the scalar magic
+ get => sub {
+ # set value lazily, and dispell for good
+ ${$_[0]} = $_[1]{total_rs}->count;
+ Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref});
+ return 1;
+ },
+ set => sub {
+ # an explicit set implies dispell as well
+ # the unless() is to work around "fun and giggles" below
+ Variable::Magic::dispell (${$_[0]}, $_[1]{magic_selfref})
+ unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
+ return 1;
+ },
+ )
+ : (
+ # the uvar magic
+ fetch => sub {
+ if ($_[2] eq $slot and !$_[1]{inactive}) {
+ my $cnt = $_[1]{total_rs}->count;
+ $_[0]->{$slot} = $cnt;
+
+ # attempting to dispell in a fetch handle (works in store), seems
+ # to invariable segfault on 5.10, 5.12, 5.13 :(
+ # so use an inactivator instead
+ #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
+ $_[1]{inactive}++;
+ }
+ return 1;
+ },
+ store => sub {
+ if (! $_[1]{inactive} and $_[2] eq $slot) {
+ #Variable::Magic::dispell (%{$_[0]}, $_[1]{magic_selfref});
+ $_[1]{inactive}++
+ unless (caller(2))[3] eq 'DBIx::Class::ResultSet::pager';
+ }
+ return 1;
+ },
+ ),
+ );
+
+ $stash->{magic_selfref} = $magic;
+ weaken ($stash->{magic_selfref}); # this fails on 5.8.1
+
+ return $magic;
+};
+
+# the tie class for 5.8.1
+{
+ package DBIx::Class::__DBIC_LAZY_RS_COUNT__;
+ use base qw/Tie::Hash/;
+
+ sub FIRSTKEY { my $dummy = scalar keys %{$_[0]{data}}; each %{$_[0]{data}} }
+ sub NEXTKEY { each %{$_[0]{data}} }
+ sub EXISTS { exists $_[0]{data}{$_[1]} }
+ sub DELETE { delete $_[0]{data}{$_[1]} }
+ sub CLEAR { %{$_[0]{data}} = () }
+ sub SCALAR { scalar %{$_[0]{data}} }
+
+ sub TIEHASH {
+ $_[1]{data} = {%{$_[1]{selfref}}};
+ %{$_[1]{selfref}} = ();
+ Scalar::Util::weaken ($_[1]{selfref});
+ return bless ($_[1], $_[0]);
+ };
+
+ sub FETCH {
+ if ($_[1] eq $_[0]{slot}) {
+ my $cnt = $_[0]{data}{$_[1]} = $_[0]{total_rs}->count;
+ untie %{$_[0]{selfref}};
+ %{$_[0]{selfref}} = %{$_[0]{data}};
+ return $cnt;
+ }
+ else {
+ $_[0]{data}{$_[1]};
+ }
+ }
+
+ sub STORE {
+ $_[0]{data}{$_[1]} = $_[2];
+ if ($_[1] eq $_[0]{slot}) {
+ untie %{$_[0]{selfref}};
+ %{$_[0]{selfref}} = %{$_[0]{data}};
+ }
+ $_[2];
+ }
+}
+
sub pager {
my ($self) = @_;
return $self->{pager} if $self->{pager};
+ if ($self->get_cache) {
+ $self->throw_exception ('Pagers on cached resultsets are not supported');
+ }
+
my $attrs = $self->{attrs};
$self->throw_exception("Can't create pager for non-paged rs")
unless $self->{attrs}{page};
# with a subselect) to get the real total count
my $count_attrs = { %$attrs };
delete $count_attrs->{$_} for qw/rows offset page pager/;
- my $total_count = (ref $self)->new($self->result_source, $count_attrs)->count;
+ my $total_rs = (ref $self)->new($self->result_source, $count_attrs);
+
+
+### the following may seem awkward and dirty, but it's a thought-experiment
+### necessary for future development of DBIx::DS. Do *NOT* change this code
+### before talking to ribasushi/mst
- return $self->{pager} = Data::Page->new(
- $total_count,
+ my $pager = Data::Page->new(
+ 0, #start with an empty set
$attrs->{rows},
- $self->{attrs}{page}
+ $self->{attrs}{page},
);
+
+ my $data_slot = 'total_entries';
+
+ # Since we are interested in a cached value (once it's set - it's set), every
+ # technique will detach from the magic-host once the time comes to fire the
+ # ->count (or in the segfaulting case of >= 5.10 it will deactivate itself)
+
+ if ($] < 5.008003) {
+ # 5.8.1 throws 'Modification of a read-only value attempted' when one tries
+ # to weakref the magic container :(
+ # tested on 5.8.1
+ tie (%$pager, 'DBIx::Class::__DBIC_LAZY_RS_COUNT__',
+ { slot => $data_slot, total_rs => $total_rs, selfref => $pager }
+ );
+ }
+ elsif ($] < 5.010) {
+ # We can use magic on the hash value slot. It's interesting that the magic is
+ # attached to the hash-slot, and does *not* stop working once I do the dummy
+ # assignments after the cast()
+ # tested on 5.8.3 and 5.8.9
+ my $magic = $mk_lazy_count_wizard->($total_rs);
+ Variable::Magic::cast ( $pager->{$data_slot}, $magic );
+
+ # this is for fun and giggles
+ $pager->{$data_slot} = -1;
+ $pager->{$data_slot} = 0;
+
+ # this does not work for scalars, but works with
+ # uvar magic below
+ #my %vals = %$pager;
+ #%$pager = ();
+ #%{$pager} = %vals;
+ }
+ else {
+ # And the uvar magic
+ # works on 5.10.1, 5.12.1 and 5.13.4 in its current form,
+ # however see the wizard maker for more notes
+ my $magic = $mk_lazy_count_wizard->($total_rs, $data_slot);
+ Variable::Magic::cast ( %$pager, $magic );
+
+ # still works
+ $pager->{$data_slot} = -1;
+ $pager->{$data_slot} = 0;
+
+ # this now works
+ my %vals = %$pager;
+ %$pager = ();
+ %{$pager} = %vals;
+ }
+
+ return $self->{pager} = $pager;
}
=head2 page
my $value = shift;
my $ref_type = ref $value;
return 1 if $ref_type eq '' || $ref_type eq 'SCALAR';
- return 1 if Scalar::Util::blessed($value);
+ return 1 if blessed $value;
return 0;
}
);
Example of creating a new row and also creating a row in a related
-C<belongs_to>resultset. Note Hashref.
+C<belongs_to> resultset. Note Hashref.
$cd_rs->create({
title=>"Music for Silly Walks",
=item Arguments: none
-=item Return Value: \@cache_objects?
+=item Return Value: \@cache_objects | undef
=back
=item Arguments: none
-=item Return Value: []
+=item Return Value: undef
=back
sub is_ordered {
my ($self) = @_;
- return scalar $self->result_source->storage->_parse_order_by($self->{attrs}{order_by});
+ return scalar $self->result_source->storage->_extract_order_columns($self->{attrs}{order_by});
}
=head2 related_resultset
# (the select/as attrs were deleted in the beginning), we need to flip all
# left joins to inner, so we get the expected results
# read the comment on top of the actual function to see what this does
- $attrs->{from} = $rsrc->schema->storage->_straight_join_to_node ($attrs->{from}, $alias);
+ $attrs->{from} = $rsrc->schema->storage->_inner_join_to_node ($attrs->{from}, $alias);
#XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
carp ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
}
else {
- $attrs->{group_by} = [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
+ my $storage = $self->result_source->schema->storage;
+ my $rs_column_list = $storage->_resolve_column_info ($attrs->{from});
+
+ my $group_spec = $attrs->{group_by} = [];
+ my %group_index;
+ for (@{$attrs->{select}}) {
+ if (! ref($_) or ref ($_) ne 'HASH' ) {
+ push @$group_spec, $_;
+ $group_index{$_}++;
+ if ($rs_column_list->{$_} and $_ !~ /\./ ) {
+ # add a fully qualified version as well
+ $group_index{"$rs_column_list->{$_}{-source_alias}.$_"}++;
+ }
+ }
+ }
# add any order_by parts that are not already present in the group_by
# we need to be careful not to add any named functions/aggregates
# i.e. select => [ ... { count => 'foo', -as 'foocount' } ... ]
- my %already_grouped = map { $_ => 1 } (@{$attrs->{group_by}});
+ for my $chunk ($storage->_extract_order_columns($attrs->{order_by})) {
- my $storage = $self->result_source->schema->storage;
+ # only consider real columns (for functions the user got to do an explicit group_by)
+ my $colinfo = $rs_column_list->{$chunk}
+ or next;
- my $rs_column_list = $storage->_resolve_column_info ($attrs->{from});
-
- for my $chunk ($storage->_parse_order_by($attrs->{order_by})) {
- if ($rs_column_list->{$chunk} && not $already_grouped{$chunk}++) {
- push @{$attrs->{group_by}}, $chunk;
- }
+ $chunk = "$colinfo->{-source_alias}.$chunk" if $chunk !~ /\./;
+ push @$group_spec, $chunk unless $group_index{$chunk}++;
}
}
}
C<select> as normal. (You may also use the C<cols> attribute, as in
earlier versions of DBIC.)
+Essentially C<columns> does the same as L</select> and L</as>.
+
+ columns => [ 'foo', { bar => 'baz' } ]
+
+is the same as
+
+ select => [qw/foo baz/],
+ as => [qw/foo bar/]
+
=head2 +columns
=over 4
projects / dbsrgits/DBIx-Class.git / blobdiff