use DBIx::Class::Carp;
use DBIx::Class::ResultSetColumn;
use Scalar::Util qw/blessed weaken reftype/;
+use DBIx::Class::_Util qw(
+ fail_on_internal_wantarray fail_on_internal_call UNRESOLVABLE_CONDITION
+);
use Try::Tiny;
use Data::Compare (); # no imports!!! guard against insane architecture
you want to check if a resultset has any results, you must use C<if $rs
!= 0>.
-=head1 CUSTOM ResultSet CLASSES THAT USE Moose
-
-If you want to make your custom ResultSet classes with L<Moose>, use a template
-similar to:
-
- package MyApp::Schema::ResultSet::User;
-
- use Moose;
- use namespace::autoclean;
- use MooseX::NonMoose;
- extends 'DBIx::Class::ResultSet';
-
- sub BUILDARGS { $_[2] }
-
- ...your code...
-
- __PACKAGE__->meta->make_immutable;
-
- 1;
-
-The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
-clash with the regular ResultSet constructor. Alternatively, you can use:
-
- __PACKAGE__->meta->make_immutable(inline_constructor => 0);
-
-The L<BUILDARGS|Moose::Manual::Construction/BUILDARGS> is necessary because the
-signature of the ResultSet C<new> is C<< ->new($source, \%args) >>.
-
=head1 EXAMPLES
=head2 Chaining resultsets
=head3 Resolving conditions and attributes
-When a resultset is chained from another resultset (ie:
-C<my $new_rs = $old_rs->search(\%extra_cond, \%attrs)>), conditions
+When a resultset is chained from another resultset (e.g.:
+C<< my $new_rs = $old_rs->search(\%extra_cond, \%attrs) >>), conditions
and attributes with the same keys need resolving.
If any of L</columns>, L</select>, L</as> are present, they reset the
See: L</search>, L</count>, L</get_column>, L</all>, L</create>.
+=head2 Custom ResultSet classes
+
+To add methods to your resultsets, you can subclass L<DBIx::Class::ResultSet>, similar to:
+
+ package MyApp::Schema::ResultSet::User;
+
+ use strict;
+ use warnings;
+
+ use base 'DBIx::Class::ResultSet';
+
+ sub active {
+ my $self = shift;
+ $self->search({ $self->current_source_alias . '.active' => 1 });
+ }
+
+ sub unverified {
+ my $self = shift;
+ $self->search({ $self->current_source_alias . '.verified' => 0 });
+ }
+
+ sub created_n_days_ago {
+ my ($self, $days_ago) = @_;
+ $self->search({
+ $self->current_source_alias . '.create_date' => {
+ '<=',
+ $self->result_source->schema->storage->datetime_parser->format_datetime(
+ DateTime->now( time_zone => 'UTC' )->subtract( days => $days_ago )
+ )}
+ });
+ }
+
+ sub users_to_warn { shift->active->unverified->created_n_days_ago(7) }
+
+ 1;
+
+See L<DBIx::Class::Schema/load_namespaces> on how DBIC can discover and
+automatically attach L<Result|DBIx::Class::Manual::ResultClass>-specific
+L<ResulSet|DBIx::Class::ResultSet> classes.
+
+=head3 ResultSet subclassing with Moose and similar constructor-providers
+
+Using L<Moose> or L<Moo> in your ResultSet classes is usually overkill, but
+you may find it useful if your ResultSets contain a lot of business logic
+(e.g. C<has xml_parser>, C<has json>, etc) or if you just prefer to organize
+your code via roles.
+
+In order to write custom ResultSet classes with L<Moo> you need to use the
+following template. The L<BUILDARGS|Moo/BUILDARGS> is necessary due to the
+unusual signature of the L<constructor provided by DBIC
+|DBIx::Class::ResultSet/new> C<< ->new($source, \%args) >>.
+
+ use Moo;
+ extends 'DBIx::Class::ResultSet';
+ sub BUILDARGS { $_[2] } # ::RS::new() expects my ($class, $rsrc, $args) = @_
+
+ ...your code...
+
+ 1;
+
+If you want to build your custom ResultSet classes with L<Moose>, you need
+a similar, though a little more elaborate template in order to interface the
+inlining of the L<Moose>-provided
+L<object constructor|Moose::Manual::Construction/WHERE'S THE CONSTRUCTOR?>,
+with the DBIC one.
+
+ package MyApp::Schema::ResultSet::User;
+
+ use Moose;
+ use MooseX::NonMoose;
+ extends 'DBIx::Class::ResultSet';
+
+ sub BUILDARGS { $_[2] } # ::RS::new() expects my ($class, $rsrc, $args) = @_
+
+ ...your code...
+
+ __PACKAGE__->meta->make_immutable;
+
+ 1;
+
+The L<MooseX::NonMoose> is necessary so that the L<Moose> constructor does not
+entirely overwrite the DBIC one (in contrast L<Moo> does this automatically).
+Alternatively, you can skip L<MooseX::NonMoose> and get by with just L<Moose>
+instead by doing:
+
+ __PACKAGE__->meta->make_immutable(inline_constructor => 0);
+
=head1 METHODS
=head2 new
sub new {
my $class = shift;
- return $class->new_result(@_) if ref $class;
+
+ if (ref $class) {
+ DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
+ return $class->new_result(@_);
+ }
my ($source, $attrs) = @_;
$source = $source->resolve
if $source->isa('DBIx::Class::ResultSourceHandle');
+
$attrs = { %{$attrs||{}} };
+ delete @{$attrs}{qw(_last_sqlmaker_alias_map _related_results_construction)};
if ($attrs->{page}) {
$attrs->{rows} ||= 10;
For a list of attributes that can be passed to C<search>, see
L</ATTRIBUTES>. For more examples of using this function, see
-L<Searching|DBIx::Class::Manual::Cookbook/Searching>. For a complete
-documentation for the first argument, see L<SQL::Abstract>
+L<Searching|DBIx::Class::Manual::Cookbook/SEARCHING>. For a complete
+documentation for the first argument, see L<SQL::Abstract/"WHERE CLAUSES">
and its extension L<DBIx::Class::SQLMaker>.
For more help on using joins with search, see L<DBIx::Class::Manual::Joining>.
my $rs = $self->search_rs( @_ );
if (wantarray) {
+ DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_WANTARRAY and my $sog = fail_on_internal_wantarray;
return $rs->all;
}
elsif (defined wantarray) {
}
my $old_attrs = { %{$self->{attrs}} };
- my $old_having = delete $old_attrs->{having};
- my $old_where = delete $old_attrs->{where};
+ my ($old_having, $old_where) = delete @{$old_attrs}{qw(having where)};
my $new_attrs = { %$old_attrs };
# older deprecated name, use only if {columns} is not there
if (my $c = delete $new_attrs->{cols}) {
+ carp_unique( "Resultset attribute 'cols' is deprecated, use 'columns' instead" );
if ($new_attrs->{columns}) {
carp "Resultset specifies both the 'columns' and the legacy 'cols' attributes - ignoring 'cols'";
}
my ($self, $attrs) = @_;
# legacy syntax
- $attrs->{'+columns'} = $self->_merge_attr($attrs->{'+columns'}, delete $attrs->{include_columns})
- if exists $attrs->{include_columns};
+ if ( exists $attrs->{include_columns} ) {
+ carp_unique( "Resultset attribute 'include_columns' is deprecated, use '+columns' instead" );
+ $attrs->{'+columns'} = $self->_merge_attr(
+ $attrs->{'+columns'}, delete $attrs->{include_columns}
+ );
+ }
# columns are always placed first, however
sub _stack_cond {
my ($self, $left, $right) = @_;
- # collapse single element top-level conditions
- # (single pass only, unlikely to need recursion)
- for ($left, $right) {
- if (ref $_ eq 'ARRAY') {
- if (@$_ == 0) {
- $_ = undef;
- }
- elsif (@$_ == 1) {
- $_ = $_->[0];
- }
- }
- elsif (ref $_ eq 'HASH') {
- my ($first, $more) = keys %$_;
+ (
+ (ref $_ eq 'ARRAY' and !@$_)
+ or
+ (ref $_ eq 'HASH' and ! keys %$_)
+ ) and $_ = undef for ($left, $right);
- # empty hash
- if (! defined $first) {
- $_ = undef;
- }
- # one element hash
- elsif (! defined $more) {
- if ($first eq '-and' and ref $_->{'-and'} eq 'HASH') {
- $_ = $_->{'-and'};
- }
- elsif ($first eq '-or' and ref $_->{'-or'} eq 'ARRAY') {
- $_ = $_->{'-or'};
- }
- }
- }
+ # either on of the two undef or both undef
+ if ( ( (defined $left) xor (defined $right) ) or ! defined $left ) {
+ return defined $left ? $left : $right;
}
- # merge hashes with weeding out of duplicates (simple cases only)
- if (ref $left eq 'HASH' and ref $right eq 'HASH') {
+ my $cond = $self->result_source->schema->storage->_collapse_cond({ -and => [$left, $right] });
- # shallow copy to destroy
- $right = { %$right };
- for (grep { exists $right->{$_} } keys %$left) {
- # the use of eq_deeply here is justified - the rhs of an
- # expression can contain a lot of twisted weird stuff
- delete $right->{$_} if Data::Compare::Compare( $left->{$_}, $right->{$_} );
- }
+ for my $c (grep { ref $cond->{$_} eq 'ARRAY' and ($cond->{$_}[0]||'') eq '-and' } keys %$cond) {
- $right = undef unless keys %$right;
- }
+ my @vals = sort @{$cond->{$c}}[ 1..$#{$cond->{$c}} ];
+ my @fin = shift @vals;
+ for my $v (@vals) {
+ push @fin, $v unless Data::Compare::Compare( $fin[-1], $v );
+ }
- if (defined $left xor defined $right) {
- return defined $left ? $left : $right;
- }
- elsif (! defined $left) {
- return undef;
- }
- else {
- return { -and => [ $left, $right ] };
+ $cond->{$c} = (@fin == 1) ? $fin[0] : [-and => @fin ];
}
+
+ $cond;
}
=head2 search_literal
method. It is equivalent to calling C<< $schema->search(\[]) >>, but if you
want to ensure columns are bound correctly, use L</search>.
-See L<DBIx::Class::Manual::Cookbook/Searching> and
+See L<DBIx::Class::Manual::Cookbook/SEARCHING> and
L<DBIx::Class::Manual::FAQ/Searching> for searching techniques that do not
require C<search_literal>.
next if $keyref eq 'ARRAY'; # has_many for multi_create
- my $rel_q = $rsrc->_resolve_condition(
+ my ($rel_cond, $crosstable) = $rsrc->_resolve_condition(
$relinfo->{cond}, $val, $key, $key
);
- die "Can't handle complex relationship conditions in find" if ref($rel_q) ne 'HASH';
- @related{keys %$rel_q} = values %$rel_q;
+
+ $self->throw_exception("Complex condition via relationship '$key' is unsupported in find()")
+ if $crosstable or ref($rel_cond) ne 'HASH';
+
+ # supplement
+ @related{keys %$rel_cond} = values %$rel_cond;
}
}
my $self = shift;
return $self->{cursor} ||= do {
- my $attrs = { %{$self->_resolved_attrs } };
+ my $attrs = $self->_resolved_attrs;
$self->result_source->storage->select(
$attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
);
my $attrs = { %{$self->_resolved_attrs} };
$self->throw_exception(
- 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
+ 'single() can not be used on resultsets collapsing a has_many. Use find( \%cond ) or next() instead'
) if $attrs->{collapse};
if ($where) {
$attrs->{from}, $attrs->{select},
$attrs->{where}, $attrs
)];
- return undef unless @$data;
- $self->{stashed_rows} = [ $data ];
- $self->_construct_objects->[0];
-}
-
-# _collapse_query
-#
-# Recursively collapse the query, accumulating values for each column.
-
-sub _collapse_query {
- my ($self, $query, $collapsed) = @_;
-
- $collapsed ||= {};
-
- if (ref $query eq 'ARRAY') {
- foreach my $subquery (@$query) {
- next unless ref $subquery; # -or
- $collapsed = $self->_collapse_query($subquery, $collapsed);
- }
- }
- elsif (ref $query eq 'HASH') {
- if (keys %$query and (keys %$query)[0] eq '-and') {
- foreach my $subquery (@{$query->{-and}}) {
- $collapsed = $self->_collapse_query($subquery, $collapsed);
- }
- }
- else {
- foreach my $col (keys %$query) {
- my $value = $query->{$col};
- $collapsed->{$col}{$value}++;
- }
- }
- }
-
- return $collapsed;
+ return undef unless @$data;
+ $self->{_stashed_rows} = [ $data ];
+ $self->_construct_results->[0];
}
=head2 get_column
$attrs->{offset} += $min;
$attrs->{rows} = ($max ? ($max - $min + 1) : 1);
return $self->search(undef, $attrs);
- #my $slice = (ref $self)->new($self->result_source, $attrs);
- #return (wantarray ? $slice->all : $slice);
}
=head2 next
return ($self->all)[0];
}
- return shift(@{$self->{stashed_objects}}) if @{ $self->{stashed_objects}||[] };
+ return shift(@{$self->{_stashed_results}}) if @{ $self->{_stashed_results}||[] };
- $self->{stashed_objects} = $self->_construct_objects
+ $self->{_stashed_results} = $self->_construct_results
or return undef;
- return shift @{$self->{stashed_objects}};
+ return shift @{$self->{_stashed_results}};
}
-# Constructs as many objects as it can in one pass while respecting
+# Constructs as many results as it can in one pass while respecting
# cursor laziness. Several modes of operation:
#
-# * Always builds everything present in @{$self->{stashed_rows}}
+# * Always builds everything present in @{$self->{_stashed_rows}}
# * If called with $fetch_all true - pulls everything off the cursor and
-# builds all objects in one pass
+# builds all result structures (or objects) in one pass
# * If $self->_resolved_attrs->{collapse} is true, checks the order_by
# and if the resultset is ordered properly by the left side:
# * Fetches stuff off the cursor until the "master object" changes,
-# and saves the last extra row (if any) in @{$self->{stashed_rows}}
+# and saves the last extra row (if any) in @{$self->{_stashed_rows}}
# OR
# * Just fetches, and collapses/constructs everything as if $fetch_all
# was requested (there is no other way to collapse except for an
# eager cursor)
# * If no collapse is requested - just get the next row, construct and
# return
-sub _construct_objects {
+sub _construct_results {
my ($self, $fetch_all) = @_;
my $rsrc = $self->result_source;
my $attrs = $self->_resolved_attrs;
- if (!$fetch_all and ! $attrs->{order_by} and $attrs->{collapse}) {
+ if (
+ ! $fetch_all
+ and
+ ! $attrs->{order_by}
+ and
+ $attrs->{collapse}
+ and
+ my @pcols = $rsrc->primary_columns
+ ) {
# default order for collapsing unless the user asked for something
- $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} $rsrc->primary_columns ];
+ $attrs->{order_by} = [ map { join '.', $attrs->{alias}, $_} @pcols ];
$attrs->{_ordered_for_collapse} = 1;
$attrs->{_order_is_artificial} = 1;
}
- my $cursor = $self->cursor;
-
# 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 = delete $self->{stashed_rows};
+ # _construct_results. Not regrowing the array twice matters a lot...
+ # a surprising amount actually
+ my $rows = delete $self->{_stashed_rows};
+
+ my $cursor; # we may not need one at all
+
+ my $did_fetch_all = $fetch_all;
if ($fetch_all) {
# FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
- $rows = [ ($rows ? @$rows : ()), $cursor->all ];
+ $rows = [ ($rows ? @$rows : ()), $self->cursor->all ];
}
elsif( $attrs->{collapse} ) {
- $attrs->{_ordered_for_collapse} = (!$attrs->{order_by}) ? 0 : do {
- my $st = $rsrc->schema->storage;
- my @ord_cols = map
- { $_->[0] }
- ( $st->_extract_order_criteria($attrs->{order_by}) )
- ;
+ # a cursor will need to be closed over in case of collapse
+ $cursor = $self->cursor;
- my $colinfos = $st->_resolve_column_info($attrs->{from}, \@ord_cols);
-
- for (0 .. $#ord_cols) {
- if (
- ! $colinfos->{$ord_cols[$_]}
- or
- $colinfos->{$ord_cols[$_]}{-result_source} != $rsrc
- ) {
- splice @ord_cols, $_;
- last;
- }
- }
-
- # since all we check here are the start of the order_by belonging to the
- # top level $rsrc, a present identifying set will mean that the resultset
- # is ordered by its leftmost table in a tsable manner
- (@ord_cols and $rsrc->_identifying_column_set({ map
- { $colinfos->{$_}{-colname} => $colinfos->{$_} }
- @ord_cols
- })) ? 1 : 0;
- } unless defined $attrs->{_ordered_for_collapse};
+ $attrs->{_ordered_for_collapse} = (
+ (
+ $attrs->{order_by}
+ and
+ $rsrc->schema
+ ->storage
+ ->_extract_colinfo_of_stable_main_source_order_by_portion($attrs)
+ ) ? 1 : 0
+ ) unless defined $attrs->{_ordered_for_collapse};
if (! $attrs->{_ordered_for_collapse}) {
- $fetch_all = 1;
+ $did_fetch_all = 1;
# instead of looping over ->next, use ->all in stealth mode
# *without* calling a ->reset afterwards
}
}
- if (! $fetch_all and ! @{$rows||[]} ) {
+ if (! $did_fetch_all and ! @{$rows||[]} ) {
# FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
+ $cursor ||= $self->cursor;
if (scalar (my @r = $cursor->next) ) {
$rows = [ \@r ];
}
return undef unless @{$rows||[]};
- my @extra_collapser_args;
- if ($attrs->{collapse} and ! $fetch_all ) {
+ # sanity check - people are too clever for their own good
+ if ($attrs->{collapse} and my $aliastypes = $attrs->{_last_sqlmaker_alias_map} ) {
- @extra_collapser_args = (
- # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
- sub { my @r = $cursor->next or return; \@r }, # how the collapser gets more rows
- ($self->{stashed_rows} = []), # where does it stuff excess
- );
+ my $multiplied_selectors;
+ for my $sel_alias ( grep { $_ ne $attrs->{alias} } keys %{ $aliastypes->{selecting} } ) {
+ if (
+ $aliastypes->{multiplying}{$sel_alias}
+ or
+ $aliastypes->{premultiplied}{$sel_alias}
+ ) {
+ $multiplied_selectors->{$_} = 1 for values %{$aliastypes->{selecting}{$sel_alias}{-seen_columns}}
+ }
+ }
+
+ for my $i (0 .. $#{$attrs->{as}} ) {
+ my $sel = $attrs->{select}[$i];
+
+ if (ref $sel eq 'SCALAR') {
+ $sel = $$sel;
+ }
+ elsif( ref $sel eq 'REF' and ref $$sel eq 'ARRAY' ) {
+ $sel = $$sel->[0];
+ }
+
+ $self->throw_exception(
+ 'Result collapse not possible - selection from a has_many source redirected to the main object'
+ ) if ($multiplied_selectors->{$sel} and $attrs->{as}[$i] !~ /\./);
+ }
}
# hotspot - skip the setter
my $infmap = $attrs->{as};
- $self->{_result_inflator}{is_hri} = do { ( $inflator_cref == (
- require DBIx::Class::ResultClass::HashRefInflator
- &&
- DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
- ) ) ? 1 : 0
- } unless defined $self->{_result_inflator}{is_hri};
+ $self->{_result_inflator}{is_core_row} = ( (
+ $inflator_cref
+ ==
+ ( \&DBIx::Class::Row::inflate_result || die "No ::Row::inflate_result() - can't happen" )
+ ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_core_row};
+
+ $self->{_result_inflator}{is_hri} = ( (
+ ! $self->{_result_inflator}{is_core_row}
+ and
+ $inflator_cref == (
+ require DBIx::Class::ResultClass::HashRefInflator
+ &&
+ DBIx::Class::ResultClass::HashRefInflator->can('inflate_result')
+ )
+ ) ? 1 : 0 ) unless defined $self->{_result_inflator}{is_hri};
+
- if ($attrs->{_single_resultclass_inflation}) {
+ if (! $attrs->{_related_results_construction}) {
# construct a much simpler array->hash folder for the one-table cases right here
if ($self->{_result_inflator}{is_hri}) {
for my $r (@$rows) {
);
}
}
- # Special-case multi-object HRI (we always prune)
- elsif ($self->{_result_inflator}{is_hri}) {
- ( $self->{_row_parser}{hri} ||= $rsrc->_mk_row_parser({
- eval => 1,
- inflate_map => $infmap,
- selection => $attrs->{select},
- collapse => $attrs->{collapse},
- premultiplied => $attrs->{_main_source_premultiplied},
- hri_style => 1,
- }) )->($rows, @extra_collapser_args);
- }
- # Regular multi-object
else {
+ my $parser_type =
+ $self->{_result_inflator}{is_hri} ? 'hri'
+ : $self->{_result_inflator}{is_core_row} ? 'classic_pruning'
+ : 'classic_nonpruning'
+ ;
- ( $self->{_row_parser}{classic} ||= $rsrc->_mk_row_parser({
+ # $args and $attrs to _mk_row_parser are separated to delineate what is
+ # core collapser stuff and what is dbic $rs specific
+ @{$self->{_row_parser}{$parser_type}}{qw(cref nullcheck)} = $rsrc->_mk_row_parser({
eval => 1,
inflate_map => $infmap,
- selection => $attrs->{select},
collapse => $attrs->{collapse},
premultiplied => $attrs->{_main_source_premultiplied},
- }) )->($rows, @extra_collapser_args);
+ hri_style => $self->{_result_inflator}{is_hri},
+ prune_null_branches => $self->{_result_inflator}{is_hri} || $self->{_result_inflator}{is_core_row},
+ }, $attrs) unless $self->{_row_parser}{$parser_type}{cref};
+
+ # column_info metadata historically hasn't been too reliable.
+ # We need to start fixing this somehow (the collapse resolver
+ # can't work without it). Add an explicit check for the *main*
+ # result, hopefully this will gradually weed out such errors
+ #
+ # FIXME - this is a temporary kludge that reduces performance
+ # It is however necessary for the time being
+ my ($unrolled_non_null_cols_to_check, $err);
+
+ if (my $check_non_null_cols = $self->{_row_parser}{$parser_type}{nullcheck} ) {
- $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows;
+ $err =
+ 'Collapse aborted due to invalid ResultSource metadata - the following '
+ . 'selections are declared non-nullable but NULLs were retrieved: '
+ ;
+
+ my @violating_idx;
+ COL: for my $i (@$check_non_null_cols) {
+ ! defined $_->[$i] and push @violating_idx, $i and next COL for @$rows;
+ }
+
+ $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
+ if @violating_idx;
+
+ $unrolled_non_null_cols_to_check = join (',', @$check_non_null_cols);
+ }
+
+ my $next_cref =
+ ($did_fetch_all or ! $attrs->{collapse}) ? undef
+ : defined $unrolled_non_null_cols_to_check ? eval sprintf <<'EOS', $unrolled_non_null_cols_to_check
+sub {
+ # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
+ my @r = $cursor->next or return;
+ if (my @violating_idx = grep { ! defined $r[$_] } (%s) ) {
+ $self->throw_exception( $err . join (', ', map { "'$infmap->[$_]'" } @violating_idx ) )
}
+ \@r
+}
+EOS
+ : sub {
+ # FIXME SUBOPTIMAL - we can do better, cursor->next/all (well diff. methods) should return a ref
+ my @r = $cursor->next or return;
+ \@r
+ }
+ ;
+
+ $self->{_row_parser}{$parser_type}{cref}->(
+ $rows,
+ $next_cref ? ( $next_cref, $self->{_stashed_rows} = [] ) : (),
+ );
- # CDBI compat stuff
- if ($attrs->{record_filter}) {
- $_ = $attrs->{record_filter}->($_) for @$rows;
+ # Special-case multi-object HRI - there is no $inflator_cref pass
+ unless ($self->{_result_inflator}{is_hri}) {
+ $_ = $inflator_cref->($res_class, $rsrc, @$_) for @$rows
+ }
}
+ # The @$rows check seems odd at first - why wouldn't we want to warn
+ # regardless? The issue is things like find() etc, where the user
+ # *knows* only one result will come back. In these cases the ->all
+ # is not a pessimization, but rather something we actually want
+ carp_unique(
+ 'Unable to properly collapse has_many results in iterator mode due '
+ . 'to order criteria - performed an eager cursor slurp underneath. '
+ . 'Consider using ->all() instead'
+ ) if ( ! $fetch_all and @$rows > 1 );
+
return $rows;
}
# software based limiting can not be ported if this $rs is to be used
# in a subquery itself (i.e. ->as_query)
if ($self->_has_resolved_attr (qw/collapse group_by offset rows/)) {
- return $self->_count_subq_rs;
+ return $self->_count_subq_rs($self->{_attrs});
}
else {
- return $self->_count_rs;
+ return $self->_count_rs($self->{_attrs});
}
}
my ($self, $attrs) = @_;
my $rsrc = $self->result_source;
- $attrs ||= $self->_resolved_attrs;
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, $attrs);
- $tmp_attrs->{as} = 'count';
-
- my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
-
- return $tmp_rs;
+ $rsrc->resultset_class->new($rsrc, {
+ %$tmp_attrs,
+ select => $rsrc->storage->_count_select ($rsrc, $attrs),
+ as => 'count',
+ })->get_column ('count');
}
#
my ($self, $attrs) = @_;
my $rsrc = $self->result_source;
- $attrs ||= $self->_resolved_attrs;
my $sub_attrs = { %$attrs };
# extra selectors do not go in the subquery and there is no point of ordering it, nor locking it
- delete @{$sub_attrs}{qw/collapse columns as select _prefetch_selector_range order_by for/};
+ delete @{$sub_attrs}{qw/collapse columns as select order_by for/};
# 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
$self->throw_exception("all() doesn't take any arguments, you probably wanted ->search(...)->all()");
}
- delete @{$self}{qw/stashed_rows stashed_objects/};
+ delete @{$self}{qw/_stashed_rows _stashed_results/};
if (my $c = $self->get_cache) {
return @$c;
$self->cursor->reset;
- my $objs = $self->_construct_objects('fetch_all') || [];
+ my $objs = $self->_construct_results('fetch_all') || [];
$self->set_cache($objs) if $self->{attrs}{cache};
sub reset {
my ($self) = @_;
- delete @{$self}{qw/stashed_rows stashed_objects/};
+ delete @{$self}{qw/_stashed_rows _stashed_results/};
$self->{all_cache_position} = 0;
$self->cursor->reset;
return $self;
my $attrs = { %{$self->_resolved_attrs} };
my $join_classifications;
- my $existing_group_by = delete $attrs->{group_by};
+ my ($existing_group_by) = delete @{$attrs}{qw(group_by _grouped_by_distinct)};
# do we need a subquery for any reason?
my $needs_subq = (
# simplify the joinmap, so we can further decide if a subq is necessary
if (!$needs_subq and @{$attrs->{from}} > 1) {
- $attrs->{from} = $storage->_prune_unused_joins ($attrs->{from}, $attrs->{select}, $self->{cond}, $attrs);
-
- # check if there are any joins left after the prune
- if ( @{$attrs->{from}} > 1 ) {
- $join_classifications = $storage->_resolve_aliastypes_from_select_args (
- [ @{$attrs->{from}}[1 .. $#{$attrs->{from}}] ],
- $attrs->{select},
- $self->{cond},
- $attrs
- );
- # any non-pruneable joins imply subq
- $needs_subq = scalar keys %{ $join_classifications->{restricting} || {} };
- }
+ ($attrs->{from}, $join_classifications) =
+ $storage->_prune_unused_joins ($attrs);
+
+ # any non-pruneable non-local restricting joins imply subq
+ $needs_subq = defined List::Util::first { $_ ne $attrs->{alias} } keys %{ $join_classifications->{restricting} || {} };
}
# check if the head is composite (by now all joins are thrown out unless $needs_subq)
);
# 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/;
+ delete $attrs->{$_} for qw/select as collapse/;
$attrs->{columns} = [ map { "$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
+
+ # this will be consumed by the pruner waaaaay down the stack
+ $attrs->{_force_prune_multiplying_joins} = 1;
+
my $subrs = (ref $self)->new($rsrc, $attrs);
if (@$idcols == 1) {
if (
$existing_group_by
or
+ # we do not need to check pre-multipliers, since if the premulti is there, its
+ # parent (who is multi) will be there too
keys %{ $join_classifications->{multiplying} || {} }
) {
# make sure if there is a supplied group_by it matches the columns compiled above
$guard = $storage->txn_scope_guard;
- $cond = [];
for my $row ($subrs->cursor->all) {
push @$cond, { map
{ $idcols->[$_] => $row->[$_] }
}
}
- my $res = $storage->$op (
+ my $res = $cond ? $storage->$op (
$rsrc,
$op eq 'update' ? $values : (),
$cond,
- );
+ ) : '0E0';
$guard->commit if $guard;
element should be a data value in the earlier specified column order.
For example:
- $Arstist_rs->populate([
+ $schema->resultset("Artist")->populate([
[ qw( artistid name ) ],
[ 100, 'A Formally Unknown Singer' ],
[ 101, 'A singer that jumped the shark two albums ago' ],
return unless @$data;
if(defined wantarray) {
- my @created = map { $self->create($_) } @$data;
+ my @created = map { $self->new_result($_)->insert } @$data;
return wantarray ? @created : \@created;
}
else {
foreach my $rel (@rels) {
next unless ref $data->[$index]->{$rel} eq "HASH";
- my $result = $self->related_resultset($rel)->create($data->[$index]->{$rel});
- my ($reverse_relname, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
+ my $result = $self->related_resultset($rel)->new_result($data->[$index]->{$rel})->insert;
+ my (undef, $reverse_relinfo) = %{$rsrc->reverse_relationship_info($rel)};
my $related = $result->result_source->_resolve_condition(
$reverse_relinfo->{cond},
$self,
}
-# populate() argumnets went over several incarnations
+# populate() arguments went over several incarnations
# What we ultimately support is AoH
sub _normalize_populate_args {
my ($self, $arg) = @_;
$self->throw_exception( "new_result takes only one argument - a hashref of values" )
if @_ > 2;
- $self->throw_exception( "new_result expects a hashref" )
+ $self->throw_exception( "Result object instantiation requires a hashref as argument" )
unless (ref $values eq 'HASH');
my ($merged_cond, $cols_from_relations) = $self->_merge_with_rscond($values);
sub _merge_with_rscond {
my ($self, $data) = @_;
- my (%new_data, @cols_from_relations);
+ my ($implied_data, @cols_from_relations);
my $alias = $self->{attrs}{alias};
if (! defined $self->{cond}) {
# just massage $data below
}
- elsif ($self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION) {
- %new_data = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
- @cols_from_relations = keys %new_data;
- }
- elsif (ref $self->{cond} ne 'HASH') {
- $self->throw_exception(
- "Can't abstract implicit construct, resultset condition not a hash"
- );
+ elsif ($self->{cond} eq UNRESOLVABLE_CONDITION) {
+ $implied_data = $self->{attrs}{related_objects}; # nothing might have been inserted yet
+ @cols_from_relations = keys %{ $implied_data || {} };
}
else {
- # precendence must be given to passed values over values inherited from
- # the cond, so the order here is important.
- my $collapsed_cond = $self->_collapse_cond($self->{cond});
- my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
-
- while ( my($col, $value) = each %implied ) {
- my $vref = ref $value;
- if (
- $vref eq 'HASH'
- and
- keys(%$value) == 1
- and
- (keys %$value)[0] eq '='
- ) {
- $new_data{$col} = $value->{'='};
- }
- elsif( !$vref or $vref eq 'SCALAR' or blessed($value) ) {
- $new_data{$col} = $value;
- }
- }
+ my $eqs = $self->result_source->schema->storage->_extract_fixed_condition_columns($self->{cond}, 'consider_nulls');
+ $implied_data = { map {
+ ( ($eqs->{$_}||'') eq UNRESOLVABLE_CONDITION ) ? () : ( $_ => $eqs->{$_} )
+ } keys %$eqs };
}
- %new_data = (
- %new_data,
- %{ $self->_remove_alias($data, $alias) },
+ return (
+ { map
+ { %{ $self->_remove_alias($_, $alias) } }
+ # precedence must be given to passed values over values inherited from
+ # the cond, so the order here is important.
+ ( $implied_data||(), $data)
+ },
+ \@cols_from_relations
);
-
- return (\%new_data, \@cols_from_relations);
}
# _has_resolved_attr
# determines if the resultset defines at least one
# of the attributes supplied
#
-# used to determine if a subquery is neccessary
+# used to determine if a subquery is necessary
#
# supports some virtual attributes:
# -join
return 0;
}
-# _collapse_cond
-#
-# Recursively collapse the condition.
-
-sub _collapse_cond {
- my ($self, $cond, $collapsed) = @_;
-
- $collapsed ||= {};
-
- if (ref $cond eq 'ARRAY') {
- foreach my $subcond (@$cond) {
- next unless ref $subcond; # -or
- $collapsed = $self->_collapse_cond($subcond, $collapsed);
- }
- }
- elsif (ref $cond eq 'HASH') {
- if (keys %$cond and (keys %$cond)[0] eq '-and') {
- foreach my $subcond (@{$cond->{-and}}) {
- $collapsed = $self->_collapse_cond($subcond, $collapsed);
- }
- }
- else {
- foreach my $col (keys %$cond) {
- my $value = $cond->{$col};
- $collapsed->{$col} = $value;
- }
- }
- }
-
- return $collapsed;
-}
-
# _remove_alias
#
# Remove the specified alias from the specified query hash. A copy is made so
my $attrs = { %{ $self->_resolved_attrs } };
- # For future use:
- #
- # in list ctx:
- # my ($sql, \@bind, \%dbi_bind_attrs) = _select_args_to_query (...)
- # $sql also has no wrapping parenthesis in list ctx
- #
- my $sqlbind = $self->result_source->storage
- ->_select_args_to_query ($attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs);
+ my $aq = $self->result_source->storage->_select_args_to_query (
+ $attrs->{from}, $attrs->{select}, $attrs->{where}, $attrs
+ );
- return $sqlbind;
+ $aq;
}
=head2 find_or_new
{ artist => 'fred' }, { key => 'artists' });
$cd->cd_to_producer->find_or_new({ producer => $producer },
- { key => 'primary });
+ { key => 'primary' });
Find an existing record from this resultset using L</find>. if none exists,
instantiate a new result object and return it. The object will not be saved
=cut
sub create {
- my ($self, $attrs) = @_;
- $self->throw_exception( "create needs a hashref" )
- unless ref $attrs eq 'HASH';
- return $self->new_result($attrs)->insert;
+ #my ($self, $col_data) = @_;
+ DBIx::Class::_ENV_::ASSERT_NO_INTERNAL_INDIRECT_CALLS and fail_on_internal_call;
+ return shift->new_result(shift)->insert;
}
=head2 find_or_create
if (keys %$hash and my $row = $self->find($hash, $attrs) ) {
return $row;
}
- return $self->create($hash);
+ return $self->new_result($hash)->insert;
}
=head2 update_or_create
return $row;
}
- return $self->create($cond);
+ return $self->new_result($cond)->insert;
}
=head2 update_or_new
sub related_resultset {
my ($self, $rel) = @_;
- return $self->{related_resultsets}{$rel} ||= do {
+ return $self->{related_resultsets}{$rel}
+ if defined $self->{related_resultsets}{$rel};
+
+ return $self->{related_resultsets}{$rel} = do {
my $rsrc = $self->result_source;
my $rel_info = $rsrc->relationship_info($rel);
#XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
delete @{$attrs}{qw(result_class alias)};
- my $related_cache;
-
- if (my $cache = $self->get_cache) {
- $related_cache = [ map
- { @{$_->related_resultset($rel)->get_cache||[]} }
- @$cache
- ];
- }
-
my $rel_source = $rsrc->related_source($rel);
my $new = do {
where => $attrs->{where},
});
};
- $new->set_cache($related_cache) if $related_cache;
+
+ if (my $cache = $self->get_cache) {
+ my @related_cache = map
+ { $_->related_resultset($rel)->get_cache || () }
+ @$cache
+ ;
+
+ $new->set_cache([ map @$_, @related_cache ]) if @related_cache == @$cache;
+ }
+
$new;
};
}
# ->_resolve_join as otherwise they get lost - captainL
my $join = $self->_merge_joinpref_attr( $attrs->{join}, $attrs->{prefetch} );
- delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
+ delete @{$attrs}{qw/join prefetch collapse group_by distinct _grouped_by_distinct select as columns +select +as +columns/};
my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
return {%$attrs, from => $from, seen_join => $seen};
}
-# FIXME - this needs to go live in Schema with the tree walker... or
-# something
-my $inflatemap_checker;
-$inflatemap_checker = sub {
- my ($rsrc, $relpaths) = @_;
-
- my $rels;
-
- for (@$relpaths) {
- $_ =~ /^ ( [^\.]+ ) \. (.+) $/x
- or next;
-
- push @{$rels->{$1}}, $2;
- }
-
- for my $rel (keys %$rels) {
- my $rel_rsrc = try {
- $rsrc->related_source ($rel)
- } catch {
- $rsrc->throw_exception(sprintf(
- "Inflation into non-existent relationship '%s' of '%s' requested, "
- . "check the inflation specification (columns/as) ending in '...%s.%s'",
- $rel,
- $rsrc->source_name,
- $rel,
- ( sort { length($a) <=> length ($b) } @{$rels->{$rel}} )[0],
- ))};
-
- $inflatemap_checker->($rel_rsrc, $rels->{$rel});
- }
-
- return;
-};
-
sub _resolved_attrs {
my $self = shift;
return $self->{_attrs} if $self->{_attrs};
my $attrs = { %{ $self->{attrs} || {} } };
- my $source = $self->result_source;
+ my $source = $attrs->{result_source} = $self->result_source;
my $alias = $attrs->{alias};
+ $self->throw_exception("Specifying distinct => 1 in conjunction with collapse => 1 is unsupported")
+ if $attrs->{collapse} and $attrs->{distinct};
+
# default selection list
$attrs->{columns} = [ $source->columns ]
unless List::Util::first { exists $attrs->{$_} } qw/columns cols select as/;
}
}
- # validate the user-supplied 'as' chain
- # folks get too confused by the (logical) exception message, need to
- # go to some lengths to clarify the text
- #
- # FIXME - this needs to go live in Schema with the tree walker... or
- # something
- $inflatemap_checker->($source, \@as);
-
$attrs->{select} = \@sel;
$attrs->{as} = \@as;
$attrs->{group_by} = [ $attrs->{group_by} ];
}
- # generate the distinct induced group_by early, as prefetch will be carried via a
- # subquery (since a group_by is present)
- if (delete $attrs->{distinct}) {
- if ($attrs->{group_by}) {
- carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
- }
- else {
- # distinct affects only the main selection part, not what prefetch may
- # add below.
- $attrs->{group_by} = $source->storage->_group_over_selection (
- $attrs->{from},
- $attrs->{select},
- $attrs->{order_by},
- );
- }
- }
# generate selections based on the prefetch helper
- my $prefetch;
+ my ($prefetch, @prefetch_select, @prefetch_as);
$prefetch = $self->_merge_joinpref_attr( {}, delete $attrs->{prefetch} )
if defined $attrs->{prefetch};
$self->throw_exception("Unable to prefetch, resultset contains an unnamed selector $attrs->{_dark_selector}{string}")
if $attrs->{_dark_selector};
+ $self->throw_exception("Specifying prefetch in conjunction with an explicit collapse => 0 is unsupported")
+ if defined $attrs->{collapse} and ! $attrs->{collapse};
+
$attrs->{collapse} = 1;
# this is a separate structure (we don't look in {from} directly)
my @prefetch = $source->_resolve_prefetch( $prefetch, $alias, $join_map );
- # we need to somehow mark which columns came from prefetch
- if (@prefetch) {
- my $sel_end = $#{$attrs->{select}};
- $attrs->{_prefetch_selector_range} = [ $sel_end + 1, $sel_end + @prefetch ];
- }
-
- push @{ $attrs->{select} }, (map { $_->[0] } @prefetch);
- push @{ $attrs->{as} }, (map { $_->[1] } @prefetch);
- }
-
- if ( ! List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
- $attrs->{_single_resultclass_inflation} = 1;
- $attrs->{collapse} = 0;
+ # save these for after distinct resolution
+ @prefetch_select = map { $_->[0] } @prefetch;
+ @prefetch_as = map { $_->[1] } @prefetch;
}
# run through the resulting joinstructure (starting from our current slot)
- # and unset collapse if proven unnesessary
+ # and unset collapse if proven unnecessary
#
# also while we are at it find out if the current root source has
# been premultiplied by previous related_source chaining
if (ref $attrs->{from} eq 'ARRAY') {
- if (@{$attrs->{from}} <= 1) {
+ if (@{$attrs->{from}} == 1) {
# no joins - no collapse
$attrs->{collapse} = 0;
}
}
}
+ # generate the distinct induced group_by before injecting the prefetched select/as parts
+ if (delete $attrs->{distinct}) {
+ if ($attrs->{group_by}) {
+ carp_unique ("Useless use of distinct on a grouped resultset ('distinct' is ignored when a 'group_by' is present)");
+ }
+ else {
+ $attrs->{_grouped_by_distinct} = 1;
+ # distinct affects only the main selection part, not what prefetch may add below
+ ($attrs->{group_by}, my $new_order) = $source->storage->_group_over_selection($attrs);
+
+ # FIXME possibly ignore a rewritten order_by (may turn out to be an issue)
+ # The thinking is: if we are collapsing the subquerying prefetch engine will
+ # rip stuff apart for us anyway, and we do not want to have a potentially
+ # function-converted external order_by
+ # ( there is an explicit if ( collapse && _grouped_by_distinct ) check in DBIHacks )
+ $attrs->{order_by} = $new_order unless $attrs->{collapse};
+ }
+ }
+
+ # inject prefetch-bound selection (if any)
+ push @{$attrs->{select}}, @prefetch_select;
+ push @{$attrs->{as}}, @prefetch_as;
+
+ # whether we can get away with the dumbest (possibly DBI-internal) collapser
+ if ( List::Util::first { $_ =~ /\./ } @{$attrs->{as}} ) {
+ $attrs->{_related_results_construction} = 1;
+ }
+
# 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
# been doing
expression). Adds C<me.> onto the start of any column without a C<.> in
it and sets C<select> from that, then auto-populates C<as> from
C<select> as normal. (You may also use the C<cols> attribute, as in
-earlier versions of DBIC.)
+earlier versions of DBIC, but this is deprecated)
Essentially C<columns> does the same as L</select> and L</as>.
- columns => [ 'foo', { bar => 'baz' } ]
+ columns => [ 'some_column', { dbic_slot => 'another_column' } ]
is the same as
- select => [qw/foo baz/],
- as => [qw/foo bar/]
+ select => [qw(some_column another_column)],
+ as => [qw(some_column dbic_slot)]
+
+If you want to individually retrieve related columns (in essence perform
+manual prefetch) you have to make sure to specify the correct inflation slot
+chain such that it matches existing relationships:
+
+ my $rs = $schema->resultset('Artist')->search({}, {
+ # required to tell DBIC to collapse has_many relationships
+ collapse => 1,
+ join => { cds => 'tracks'},
+ '+columns' => {
+ 'cds.cdid' => 'cds.cdid',
+ 'cds.tracks.title' => 'tracks.title',
+ },
+ });
=head2 +columns
+B<NOTE:> You B<MUST> explicitly quote C<'+columns'> when using this attribute.
+Not doing so causes Perl to incorrectly interpret C<+columns> as a bareword
+with a unary plus operator before it, which is the same as simply C<columns>.
+
=over 4
-=item Value: \@columns
+=item Value: \@extra_columns
=back
-Indicates additional columns to be selected from storage. Works the same
-as L</columns> but adds columns to the selection. (You may also use the
-C<include_columns> attribute, as in earlier versions of DBIC). For
-example:-
+Indicates additional columns to be selected from storage. Works the same as
+L</columns> but adds columns to the current selection. (You may also use the
+C<include_columns> attribute, as in earlier versions of DBIC, but this is
+deprecated)
$schema->resultset('CD')->search(undef, {
'+columns' => ['artist.name'],
column (or relationship) accessor, and 'name' is the name of the column
accessor in the related table.
-B<NOTE:> You need to explicitly quote '+columns' when defining the attribute.
-Not doing so causes Perl to incorrectly interpret +columns as a bareword with a
-unary plus operator before it.
-
-=head2 include_columns
-
-=over 4
-
-=item Value: \@columns
-
-=back
-
-Deprecated. Acts as a synonym for L</+columns> for backward compatibility.
-
=head2 select
=over 4
e.g. an C<ORDER BY> clause. This is done via the C<-as> B<select function
attribute> supplied as shown in the example above.
-B<NOTE:> You need to explicitly quote '+select'/'+as' when defining the attributes.
-Not doing so causes Perl to incorrectly interpret them as a bareword with a
-unary plus operator before it.
-
=head2 +select
+B<NOTE:> You B<MUST> explicitly quote C<'+select'> when using this attribute.
+Not doing so causes Perl to incorrectly interpret C<+select> as a bareword
+with a unary plus operator before it, which is the same as simply C<select>.
+
=over 4
-Indicates additional columns to be selected from storage. Works the same as
-L</select> but adds columns to the default selection, instead of specifying
-an explicit list.
+=item Value: \@extra_select_columns
=back
+Indicates additional columns to be selected from storage. Works the same as
+L</select> but adds columns to the current selection, instead of specifying
+a new explicit list.
+
=head2 as
=over 4
=back
-Indicates column names for object inflation. That is L</as> indicates the
+Indicates DBIC-side names for object inflation. That is L</as> indicates the
slot name in which the column value will be stored within the
L<Row|DBIx::Class::Row> object. The value will then be accessible via this
identifier by the C<get_column> method (or via the object accessor B<if one
=head2 +as
+B<NOTE:> You B<MUST> explicitly quote C<'+as'> when using this attribute.
+Not doing so causes Perl to incorrectly interpret C<+as> as a bareword
+with a unary plus operator before it, which is the same as simply C<as>.
+
=over 4
-Indicates additional column names for those added via L</+select>. See L</as>.
+=item Value: \@extra_inflation_names
=back
+Indicates additional inflation names for selectors added via L</+select>. See L</as>.
+
=head2 join
=over 4
If an L</order_by> is already declared, and orders the resultset in a way that
makes collapsing as described above impossible (e.g. C<< ORDER BY
has_many_rel.column >> or C<ORDER BY RANDOM()>), DBIC will automatically
-switch to "eager" mode and slurp the entire resultset before consturcting the
+switch to "eager" mode and slurp the entire resultset before constructing the
first object returned by L</next>.
Setting this attribute on a resultset that does not join any has_many
=back
-Set to 1 to group by all columns. If the resultset already has a group_by
-attribute, this setting is ignored and an appropriate warning is issued.
+Set to 1 to automatically generate a L</group_by> clause based on the selection
+(including intelligent handling of L</order_by> contents). Note that the group
+criteria calculation takes place over the B<final> selection. This includes
+any L</+columns>, L</+select> or L</order_by> additions in subsequent
+L</search> calls, and standalone columns selected via
+L<DBIx::Class::ResultSetColumn> (L</get_column>). A notable exception are the
+extra selections specified via L</prefetch> - such selections are explicitly
+excluded from group criteria calculations.
+
+If the final ResultSet also explicitly defines a L</group_by> attribute, this
+setting is ignored and an appropriate warning is issued.
=head2 where
=item dbic_colname
Used to fill in missing sqlt_datatype and sqlt_size attributes (if they are
-explicitly specified they are never overriden). Also used by some weird DBDs,
+explicitly specified they are never overridden). Also used by some weird DBDs,
where the column name should be available at bind_param time (e.g. Oracle).
=back
[ $name => $val ] === [ { dbic_colname => $name }, $val ]
[ \$dt => $val ] === [ { sqlt_datatype => $dt }, $val ]
[ undef, $val ] === [ {}, $val ]
+ $val === [ {}, $val ]
=head1 AUTHOR AND CONTRIBUTORS