'bool' => "_bool",
fallback => 1;
use Carp::Clan qw/^DBIx::Class/;
+use DBIx::Class::Exception;
use Data::Page;
use Storable;
use DBIx::Class::ResultSetColumn;
=head1 SYNOPSIS
my $users_rs = $schema->resultset('User');
+ while( $user = $users_rs->next) {
+ print $user->username;
+ }
+
my $registered_users_rs = $schema->resultset('User')->search({ registered => 1 });
my @cds_in_2005 = $schema->resultset('CD')->search({ year => 2005 })->all();
=head1 OVERLOADING
If a resultset is used in a numeric context it returns the L</count>.
-However, if it is used in a booleand context it is always true. So if
+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.
$rows = $self->get_cache;
}
+ # reset the selector list
+ if (List::Util::first { exists $attrs->{$_} } qw{columns select as}) {
+ delete @{$our_attrs}{qw{select as columns +select +as +columns include_columns}};
+ }
+
my $new_attrs = { %{$our_attrs}, %{$attrs} };
# merge new attrs into inherited
- foreach my $key (qw/join prefetch +select +as bind/) {
+ foreach my $key (qw/join prefetch +select +as +columns include_columns bind/) {
next unless exists $attrs->{$key};
$new_attrs->{$key} = $self->_merge_attr($our_attrs->{$key}, $attrs->{$key});
}
}
my $rs = (ref $self)->new($self->result_source, $new_attrs);
- if ($rows) {
- $rs->set_cache($rows);
- }
+
+ $rs->set_cache($rows) if ($rows);
+
return $rs;
}
# in ::Relationship::Base::search_related (the row method), and furthermore
# the relationship is of the 'single' type. This means that the condition
# provided by the relationship (already attached to $self) is sufficient,
- # as there can be only one row in the databse that would satisfy the
+ # as there can be only one row in the database that would satisfy the
# relationship
}
else {
my $where = $self->_collapse_cond($self->{attrs}{where} || {});
my $num_where = scalar keys %$where;
- my @unique_queries;
+ my (@unique_queries, %seen_column_combinations);
foreach my $name (@constraint_names) {
- my @unique_cols = $self->result_source->unique_constraint_columns($name);
- my $unique_query = $self->_build_unique_query($query, \@unique_cols);
+ my @constraint_cols = $self->result_source->unique_constraint_columns($name);
+
+ my $constraint_sig = join "\x00", sort @constraint_cols;
+ next if $seen_column_combinations{$constraint_sig}++;
+
+ my $unique_query = $self->_build_unique_query($query, \@constraint_cols);
- my $num_cols = scalar @unique_cols;
+ my $num_cols = scalar @constraint_cols;
my $num_query = scalar keys %$unique_query;
my $total = $num_query + $num_where;
=head2 search_related_rs
This method works exactly the same as search_related, except that
-it guarantees a restultset, even in list context.
+it guarantees a resultset, even in list context.
=cut
=item B<Note>
-As of 0.08100, this method enforces the assumption that the preceeding
+As of 0.08100, this method enforces the assumption that the preceding
query returns only one row. If more than one row is returned, you will receive
a warning:
sub _collapse_result {
my ($self, $as_proto, $row) = @_;
- # if the first row that ever came in is totally empty - this means we got
- # hit by a smooth^Wempty left-joined resultset. Just noop in that case
- # instead of producing a {}
- #
- my $has_def;
- for (@$row) {
- if (defined $_) {
- $has_def++;
- last;
- }
- }
- return undef unless $has_def;
-
my @copy = @$row;
# 'foo' => [ undef, 'foo' ]
# without having to contruct the full hash
if (keys %collapse) {
- my %pri = map { ($_ => 1) } $self->result_source->primary_columns;
+ my %pri = map { ($_ => 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[$i][1]}) {
if ($result_class) {
$self->ensure_class_loaded($result_class);
$self->_result_class($result_class);
+ $self->{attrs}{result_class} = $result_class if ref $self;
}
$self->_result_class;
}
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 a count
- delete $tmp_attrs->{$_} for (qw/select as rows offset order_by record_filter/);
+ # only take pieces we need for a simple count
+ my $tmp_attrs = { map
+ { $_ => $attrs->{$_} }
+ qw/ alias from where bind join /
+ };
# overwrite the selector (supplied by the storage)
$tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $tmp_attrs);
$tmp_attrs->{as} = 'count';
- # read the comment on top of the actual function to see what this does
- $tmp_attrs->{from} = $self->_switch_to_inner_join_if_needed (
- $tmp_attrs->{from}, $tmp_attrs->{alias}
- );
-
my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
return $tmp_rs;
my ($self, $attrs) = @_;
my $rsrc = $self->result_source;
- $attrs ||= $self->_resolved_attrs_copy;
-
- my $sub_attrs = { %$attrs };
+ $attrs ||= $self->_resolved_attrs;
- # extra selectors do not go in the subquery and there is no point of ordering it
- delete $sub_attrs->{$_} for qw/collapse select _prefetch_select as order_by/;
+ my $sub_attrs = { map
+ { $_ => $attrs->{$_} }
+ qw/ alias from where bind join group_by having rows offset /
+ };
- # if we 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
- if ( keys %{$attrs->{collapse}} ) {
- $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->primary_columns) ]
+ # 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
+ if ( keys %{$attrs->{collapse}} ) {
+ $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->_pri_cols) ]
}
- $sub_attrs->{select} = $rsrc->storage->_subq_count_select ($rsrc, $sub_attrs);
-
- # read the comment on top of the actual function to see what this does
- $sub_attrs->{from} = $self->_switch_to_inner_join_if_needed (
- $sub_attrs->{from}, $sub_attrs->{alias}
- );
-
- # this is so that ordering can be thrown away in things like Top limit
- $sub_attrs->{-for_count_only} = 1;
-
- my $sub_rs = $rsrc->resultset_class->new ($rsrc, $sub_attrs);
-
- $attrs->{from} = [{
- -alias => 'count_subq',
- -source_handle => $rsrc->handle,
- count_subq => $sub_rs->as_query,
- }];
+ # Calculate subquery selector
+ if (my $g = $sub_attrs->{group_by}) {
- # the subquery replaces this
- delete $attrs->{$_} for qw/where bind collapse group_by having having_bind rows offset/;
-
- return $self->_count_rs ($attrs);
-}
-
-
-# The DBIC relationship chaining implementation is pretty simple - every
-# new related_relationship is pushed onto the {from} stack, and the {select}
-# window simply slides further in. This means that when we count somewhere
-# in the middle, we got to make sure that everything in the join chain is an
-# actual inner join, otherwise the count will come back with unpredictable
-# results (a resultset may be generated with _some_ rows regardless of if
-# the relation which the $rs currently selects has rows or not). E.g.
-# $artist_rs->cds->count - normally generates:
-# SELECT COUNT( * ) FROM artist me LEFT JOIN cd cds ON cds.artist = me.artistid
-# which actually returns the number of artists * (number of cds || 1)
-#
-# So what we do here is crawl {from}, determine if the current alias is at
-# the top of the stack, and if not - make sure the chain is inner-joined down
-# to the root.
-#
-sub _switch_to_inner_join_if_needed {
- my ($self, $from, $alias) = @_;
-
- # subqueries and other oddness is naturally not supported
- return $from if (
- ref $from ne 'ARRAY'
- ||
- @$from <= 1
- ||
- ref $from->[0] ne 'HASH'
- ||
- ! $from->[0]{-alias}
- ||
- $from->[0]{-alias} eq $alias
- );
-
- my $switch_branch;
- JOINSCAN:
- for my $j (@{$from}[1 .. $#$from]) {
- if ($j->[0]{-alias} eq $alias) {
- $switch_branch = $j->[0]{-join_path};
- last JOINSCAN;
+ # necessary as the group_by may refer to aliased functions
+ my $sel_index;
+ for my $sel (@{$attrs->{select}}) {
+ $sel_index->{$sel->{-as}} = $sel
+ if (ref $sel eq 'HASH' and $sel->{-as});
}
- }
-
- # something else went wrong
- return $from unless $switch_branch;
-
- # So it looks like we will have to switch some stuff around.
- # local() is useless here as we will be leaving the scope
- # anyway, and deep cloning is just too fucking expensive
- # So replace the inner hashref manually
- my @new_from = ($from->[0]);
- my $sw_idx = { map { $_ => 1 } @$switch_branch };
-
- for my $j (@{$from}[1 .. $#$from]) {
- my $jalias = $j->[0]{-alias};
- if ($sw_idx->{$jalias}) {
- my %attrs = %{$j->[0]};
- delete $attrs{-join_type};
- push @new_from, [
- \%attrs,
- @{$j}[ 1 .. $#$j ],
- ];
- }
- else {
- push @new_from, $j;
+ for my $g_part (@$g) {
+ push @{$sub_attrs->{select}}, $sel_index->{$g_part} || $g_part;
}
}
+ else {
+ my @pcols = map { "$attrs->{alias}.$_" } ($rsrc->primary_columns);
+ $sub_attrs->{select} = @pcols ? \@pcols : [ 1 ];
+ }
- return \@new_from;
+ return $rsrc->resultset_class
+ ->new ($rsrc, $sub_attrs)
+ ->as_subselect_rs
+ ->search ({}, { columns => { count => $rsrc->storage->_count_select ($rsrc, $attrs) } })
+ -> get_column ('count');
}
-
sub _bool {
return 1;
}
my $rsrc = $self->result_source;
+ # if a condition exists we need to strip all table qualifiers
+ # if this is not possible we'll force a subquery below
+ my $cond = $rsrc->schema->storage->_strip_cond_qualifiers ($self->{cond});
+
my $needs_group_by_subq = $self->_has_resolved_attr (qw/collapse group_by -join/);
- my $needs_subq = $self->_has_resolved_attr (qw/row offset/);
+ my $needs_subq = $needs_group_by_subq || (not defined $cond) || $self->_has_resolved_attr(qw/row offset/);
if ($needs_group_by_subq or $needs_subq) {
my $attrs = $self->_resolved_attrs_copy;
delete $attrs->{$_} for qw/collapse select as/;
- $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->primary_columns) ];
+ $attrs->{columns} = [ map { "$attrs->{alias}.$_" } ($self->result_source->_pri_cols) ];
if ($needs_group_by_subq) {
# make sure no group_by was supplied, or if there is one - make sure it matches
return $rsrc->storage->$op(
$rsrc,
$op eq 'update' ? $values : (),
- $self->_cond_for_update_delete,
+ $cond,
);
}
}
-
-# _cond_for_update_delete
-#
-# update/delete require the condition to be modified to handle
-# the differing SQL syntax available. This transforms the $self->{cond}
-# appropriately, returning the new condition.
-
-sub _cond_for_update_delete {
- my ($self, $full_cond) = @_;
- my $cond = {};
-
- $full_cond ||= $self->{cond};
- # No-op. No condition, we're updating/deleting everything
- return $cond unless ref $full_cond;
-
- if (ref $full_cond eq 'ARRAY') {
- $cond = [
- map {
- my %hash;
- foreach my $key (keys %{$_}) {
- $key =~ /([^.]+)$/;
- $hash{$1} = $_->{$key};
- }
- \%hash;
- } @{$full_cond}
- ];
- }
- elsif (ref $full_cond eq 'HASH') {
- if ((keys %{$full_cond})[0] eq '-and') {
- $cond->{-and} = [];
- my @cond = @{$full_cond->{-and}};
- for (my $i = 0; $i < @cond; $i++) {
- my $entry = $cond[$i];
- my $hash;
- if (ref $entry eq 'HASH') {
- $hash = $self->_cond_for_update_delete($entry);
- }
- else {
- $entry =~ /([^.]+)$/;
- $hash->{$1} = $cond[++$i];
- }
- push @{$cond->{-and}}, $hash;
- }
- }
- else {
- foreach my $key (keys %{$full_cond}) {
- $key =~ /([^.]+)$/;
- $cond->{$1} = $full_cond->{$key};
- }
- }
- }
- else {
- $self->throw_exception("Can't update/delete on resultset with condition unless hash or array");
- }
-
- return $cond;
-}
-
-
=head2 update
=over 4
my ($self, $values) = @_;
$self->throw_exception('Values for update_all must be a hash')
unless ref $values eq 'HASH';
- foreach my $obj ($self->all) {
- $obj->set_columns($values)->update;
- }
+
+ my $guard = $self->result_source->schema->txn_scope_guard;
+ $_->update($values) for $self->all;
+ $guard->commit;
return 1;
}
will not run DBIC cascade triggers. See L</delete_all> if you need triggers
to run. See also L<DBIx::Class::Row/delete>.
-Return value will be the amount of rows deleted; exact type of return value
+Return value will be the number of rows deleted; exact type of return value
is storage-dependent.
=cut
$self->throw_exception('delete_all does not accept any arguments')
if @_;
+ my $guard = $self->result_source->schema->txn_scope_guard;
$_->delete for $self->all;
+ $guard->commit;
return 1;
}
],
},
{ artistid => 5, name => 'Angsty-Whiny Girl', cds => [
- { title => 'My parents sold me to a record company' ,year => 2005 },
+ { title => 'My parents sold me to a record company', year => 2005 },
{ title => 'Why Am I So Ugly?', year => 2006 },
{ title => 'I Got Surgery and am now Popular', year => 2007 }
],
[qw/artistid name/],
[100, 'A Formally Unknown Singer'],
[101, 'A singer that jumped the shark two albums ago'],
- [102, 'An actually cool singer.'],
+ [102, 'An actually cool singer'],
]);
Please note an important effect on your data when choosing between void and
=cut
sub populate {
- my $self = shift @_;
- my $data = ref $_[0][0] eq 'HASH'
- ? $_[0] : ref $_[0][0] eq 'ARRAY' ? $self->_normalize_populate_args($_[0]) :
- $self->throw_exception('Populate expects an arrayref of hashes or arrayref of arrayrefs');
+ my $self = shift;
+
+ # cruft placed in standalone method
+ my $data = $self->_normalize_populate_args(@_);
if(defined wantarray) {
my @created;
}
return wantarray ? @created : \@created;
} else {
- my ($first, @rest) = @$data;
+ my $first = $data->[0];
+
+ # if a column is a registered relationship, and is a non-blessed hash/array, consider
+ # it relationship data
+ my (@rels, @columns);
+ for (keys %$first) {
+ my $ref = ref $first->{$_};
+ $self->result_source->has_relationship($_) && ($ref eq 'ARRAY' or $ref eq 'HASH')
+ ? push @rels, $_
+ : push @columns, $_
+ ;
+ }
- my @names = grep {!ref $first->{$_}} keys %$first;
- my @rels = grep { $self->result_source->has_relationship($_) } keys %$first;
my @pks = $self->result_source->primary_columns;
## do the belongs_to relationships
delete $data->[$index]->{$rel};
$data->[$index] = {%{$data->[$index]}, %$related};
- push @names, keys %$related if $index == 0;
+ push @columns, keys %$related if $index == 0;
}
}
- ## do bulk insert on current row
- my @values = map { [ @$_{@names} ] } @$data;
+ ## inherit the data locked in the conditions of the resultset
+ my ($rs_data) = $self->_merge_cond_with_data({});
+ delete @{$rs_data}{@columns};
+ my @inherit_cols = keys %$rs_data;
+ my @inherit_data = values %$rs_data;
+ ## do bulk insert on current row
$self->result_source->storage->insert_bulk(
$self->result_source,
- \@names,
- \@values,
+ [@columns, @inherit_cols],
+ [ map { [ @$_{@columns}, @inherit_data ] } @$data ],
);
## do the has_many relationships
foreach my $rel (@rels) {
next unless $item->{$rel} && ref $item->{$rel} eq "ARRAY";
- my $parent = $self->find(map {{$_=>$item->{$_}} } @pks)
+ my $parent = $self->find({map { $_ => $item->{$_} } @pks})
|| $self->throw_exception('Cannot find the relating object.');
my $child = $parent->$rel;
}
}
-=head2 _normalize_populate_args ($args)
-
-Private method used by L</populate> to normalize its incoming arguments. Factored
-out in case you want to subclass and accept new argument structures to the
-L</populate> method.
-
-=cut
+# populate() argumnets went over several incarnations
+# What we ultimately support is AoH
sub _normalize_populate_args {
- my ($self, $data) = @_;
- my @names = @{shift(@$data)};
- my @results_to_create;
- foreach my $datum (@$data) {
- my %result_to_create;
- foreach my $index (0..$#names) {
- $result_to_create{$names[$index]} = $$datum[$index];
+ my ($self, $arg) = @_;
+
+ if (ref $arg eq 'ARRAY') {
+ if (ref $arg->[0] eq 'HASH') {
+ return $arg;
+ }
+ elsif (ref $arg->[0] eq 'ARRAY') {
+ my @ret;
+ my @colnames = @{$arg->[0]};
+ foreach my $values (@{$arg}[1 .. $#$arg]) {
+ push @ret, { map { $colnames[$_] => $values->[$_] } (0 .. $#colnames) };
+ }
+ return \@ret;
}
- push @results_to_create, \%result_to_create;
}
- return \@results_to_create;
+
+ $self->throw_exception('Populate expects an arrayref of hashrefs or arrayref of arrayrefs');
}
=head2 pager
$self->throw_exception( "new_result needs a hash" )
unless (ref $values eq 'HASH');
- my %new;
+ my ($merged_cond, $cols_from_relations) = $self->_merge_cond_with_data($values);
+
+ my %new = (
+ %$merged_cond,
+ @$cols_from_relations
+ ? (-cols_from_relations => $cols_from_relations)
+ : (),
+ -source_handle => $self->_source_handle,
+ -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
+ );
+
+ return $self->result_class->new(\%new);
+}
+
+# _merge_cond_with_data
+#
+# Takes a simple hash of K/V data and returns its copy merged with the
+# condition already present on the resultset. Additionally returns an
+# arrayref of value/condition names, which were inferred from related
+# objects (this is needed for in-memory related objects)
+sub _merge_cond_with_data {
+ my ($self, $data) = @_;
+
+ my (%new_data, @cols_from_relations);
+
my $alias = $self->{attrs}{alias};
- if (
- defined $self->{cond}
- && $self->{cond} eq $DBIx::Class::ResultSource::UNRESOLVABLE_CONDITION
- ) {
- %new = %{ $self->{attrs}{related_objects} || {} }; # nothing might have been inserted yet
- $new{-from_resultset} = [ keys %new ] if keys %new;
- } else {
+ 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') {
$self->throw_exception(
- "Can't abstract implicit construct, condition not a hash"
- ) if ($self->{cond} && !(ref $self->{cond} eq 'HASH'));
-
- my $collapsed_cond = (
- $self->{cond}
- ? $self->_collapse_cond($self->{cond})
- : {}
+ "Can't abstract implicit construct, resultset condition not a hash"
);
-
+ }
+ else {
# precendence must be given to passed values over values inherited from
# the cond, so the order here is important.
- my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
- while( my($col,$value) = each %implied ){
- if(ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '='){
- $new{$col} = $value->{'='};
+ my $collapsed_cond = $self->_collapse_cond($self->{cond});
+ my %implied = %{$self->_remove_alias($collapsed_cond, $alias)};
+
+ while ( my($col, $value) = each %implied ) {
+ if (ref($value) eq 'HASH' && keys(%$value) && (keys %$value)[0] eq '=') {
+ $new_data{$col} = $value->{'='};
next;
}
- $new{$col} = $value if $self->_is_deterministic_value($value);
+ $new_data{$col} = $value if $self->_is_deterministic_value($value);
}
}
- %new = (
- %new,
- %{ $self->_remove_alias($values, $alias) },
- -source_handle => $self->_source_handle,
- -result_source => $self->result_source, # DO NOT REMOVE THIS, REQUIRED
+ %new_data = (
+ %new_data,
+ %{ $self->_remove_alias($data, $alias) },
);
- return $self->result_class->new(\%new);
+ return (\%new_data, \@cols_from_relations);
}
# _is_deterministic_value
return \%unaliased;
}
-=head2 as_query (EXPERIMENTAL)
+=head2 as_query
=over 4
This is generally used as the RHS for a subquery.
-B<NOTE>: This feature is still experimental.
-
=cut
sub as_query {
a unique constraint that is not the primary key, or looking for
related rows.
-If you want objects to be saved immediately, use L</find_or_create> instead.
+If you want objects to be saved immediately, use L</find_or_create>
+instead.
-B<Note>: C<find_or_new> is probably not what you want when creating a
-new row in a table that uses primary keys supplied by the
-database. Passing in a primary key column with a value of I<undef>
-will cause L</find> to attempt to search for a row with a value of
-I<NULL>.
+B<Note>: Take care when using C<find_or_new> with a table having
+columns with default values that you intend to be automatically
+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<find_or_new>, even when set to C<undef>.
=cut
B<keyed on the relationship name>. If the relationship is of type C<multi>
(L<DBIx::Class::Relationship/has_many>) - pass an arrayref of hashrefs.
The process will correctly identify columns holding foreign keys, and will
-transparrently populate them from the keys of the corresponding relation.
+transparently populate them from the keys of the corresponding relation.
This can be applied recursively, and will work correctly for a structure
with an arbitrary depth and width, as long as the relationships actually
exists and the correct column data has been supplied.
the find has completed and before the create has started. To avoid
this problem, use find_or_create() inside a transaction.
-B<Note>: C<find_or_create> is probably not what you want when creating
-a new row in a table that uses primary keys supplied by the
-database. Passing in a primary key column with a value of I<undef>
-will cause L</find> to attempt to search for a row with a value of
-I<NULL>.
+B<Note>: Take care when using C<find_or_create> with a table having
+columns with default values that you intend to be automatically
+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<find_or_create>, even when set to C<undef>.
See also L</find> and L</update_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
producer => $producer,
name => 'harry',
}, {
- key => 'primary,
+ key => 'primary',
});
See also L</find> and L</find_or_create>. For information on how to declare
unique constraints, see L<DBIx::Class::ResultSource/add_unique_constraint>.
-B<Note>: C<update_or_create> is probably not what you want when
-looking for a row in a table that uses primary keys supplied by the
-database, unless you actually have a key value. Passing in a primary
-key column with a value of I<undef> will cause L</find> to attempt to
-search for a row with a value of I<NULL>.
+B<Note>: Take care when using C<update_or_create> with a table having
+columns with default values that you intend to be automatically
+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<update_or_create>, even when set to C<undef>.
=cut
$cd->insert;
}
-See also L</find>, L</find_or_create> and L<find_or_new>.
+B<Note>: Take care when using C<update_or_new> with a table having
+columns with default values that you intend to be automatically
+supplied by the database (e.g. an auto_increment primary key column).
+In normal usage, the value of such columns should NOT be included at
+all in the call to C<update_or_new>, even when set to C<undef>.
+
+See also L</find>, L</find_or_create> and L</find_or_new>.
=cut
shift->set_cache(undef);
}
+=head2 is_paged
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: true, if the resultset has been paginated
+
+=back
+
+=cut
+
+sub is_paged {
+ my ($self) = @_;
+ return !!$self->{attrs}{page};
+}
+
+=head2 is_ordered
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: true, if the resultset has been ordered with C<order_by>.
+
+=back
+
+=cut
+
+sub is_ordered {
+ my ($self) = @_;
+ return scalar $self->result_source->storage->_parse_order_by($self->{attrs}{order_by});
+}
+
=head2 related_resultset
=over 4
$self->{related_resultsets} ||= {};
return $self->{related_resultsets}{$rel} ||= do {
- my $rel_info = $self->result_source->relationship_info($rel);
+ my $rsrc = $self->result_source;
+ my $rel_info = $rsrc->relationship_info($rel);
$self->throw_exception(
- "search_related: result source '" . $self->result_source->source_name .
+ "search_related: result source '" . $rsrc->source_name .
"' has no such relationship $rel")
unless $rel_info;
- my ($from,$seen) = $self->_chain_relationship($rel);
+ my $attrs = $self->_chain_relationship($rel);
+
+ my $join_count = $attrs->{seen_join}{$rel};
+
+ my $alias = $self->result_source->storage
+ ->relname_to_table_alias($rel, $join_count);
+
+ # since this is search_related, and we already slid the select window inwards
+ # (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);
- my $join_count = $seen->{$rel};
- my $alias = ($join_count > 1 ? join('_', $rel, $join_count) : $rel);
#XXX - temp fix for result_class bug. There likely is a more elegant fix -groditi
- my %attrs = %{$self->{attrs}||{}};
- delete @attrs{qw(result_class alias)};
+ delete @{$attrs}{qw(result_class alias)};
my $new_cache;
}
}
- my $rel_source = $self->result_source->related_source($rel);
+ my $rel_source = $rsrc->related_source($rel);
my $new = do {
# to work sanely (e.g. RestrictWithObject wants to be able to add
# extra query restrictions, and these may need to be $alias.)
- my $attrs = $rel_source->resultset_attributes;
- local $attrs->{alias} = $alias;
+ my $rel_attrs = $rel_source->resultset_attributes;
+ local $rel_attrs->{alias} = $alias;
$rel_source->resultset
->search_rs(
undef, {
- %attrs,
- join => undef,
- prefetch => undef,
- select => undef,
- as => undef,
- where => $self->{cond},
- seen_join => $seen,
- from => $from,
+ %$attrs,
+ where => $attrs->{where},
});
};
$new->set_cache($new_cache) if $new_cache;
return ($self->{attrs} || {})->{alias} || 'me';
}
+=head2 as_subselect_rs
+
+=over 4
+
+=item Arguments: none
+
+=item Return Value: $resultset
+
+=back
+
+Act as a barrier to SQL symbols. The resultset provided will be made into a
+"virtual view" by including it as a subquery within the from clause. From this
+point on, any joined tables are inaccessible to ->search on the resultset (as if
+it were simply where-filtered without joins). For example:
+
+ my $rs = $schema->resultset('Bar')->search({'x.name' => 'abc'},{ join => 'x' });
+
+ # 'x' now pollutes the query namespace
+
+ # So the following works as expected
+ my $ok_rs = $rs->search({'x.other' => 1});
+
+ # But this doesn't: instead of finding a 'Bar' related to two x rows (abc and
+ # def) we look for one row with contradictory terms and join in another table
+ # (aliased 'x_2') which we never use
+ my $broken_rs = $rs->search({'x.name' => 'def'});
+
+ my $rs2 = $rs->as_subselect_rs;
+
+ # doesn't work - 'x' is no longer accessible in $rs2, having been sealed away
+ my $not_joined_rs = $rs2->search({'x.other' => 1});
+
+ # works as expected: finds a 'table' row related to two x rows (abc and def)
+ my $correctly_joined_rs = $rs2->search({'x.name' => 'def'});
+
+Another example of when one might use this would be to select a subset of
+columns in a group by clause:
+
+ my $rs = $schema->resultset('Bar')->search(undef, {
+ group_by => [qw{ id foo_id baz_id }],
+ })->as_subselect_rs->search(undef, {
+ columns => [qw{ id foo_id }]
+ });
+
+In the above example normally columns would have to be equal to the group by,
+but because we isolated the group by into a subselect the above works.
+
+=cut
+
+sub as_subselect_rs {
+ my $self = shift;
+
+ my $attrs = $self->_resolved_attrs;
+
+ my $fresh_rs = (ref $self)->new (
+ $self->result_source
+ );
+
+ # these pieces will be locked in the subquery
+ delete $fresh_rs->{cond};
+ delete @{$fresh_rs->{attrs}}{qw/where bind/};
+
+ return $fresh_rs->search( {}, {
+ from => [{
+ $attrs->{alias} => $self->as_query,
+ -alias => $attrs->{alias},
+ -source_handle => $self->result_source->handle,
+ }],
+ alias => $attrs->{alias},
+ });
+}
+
# This code is called by search_related, and makes sure there
# is clear separation between the joins before, during, and
# after the relationship. This information is needed later
# with a relation_chain_depth less than the depth of the
# current prefetch is not considered)
#
-# The increments happen in 1/2s to make it easier to correlate the
-# join depth with the join path. An integer means a relationship
-# specified via a search_related, whereas a fraction means an added
-# join/prefetch via attributes
+# The increments happen twice per join. An even number means a
+# relationship specified via a search_related, whereas an odd
+# number indicates a join/prefetch added via attributes
+#
+# Also this code will wrap the current resultset (the one we
+# chain to) in a subselect IFF it contains limiting attributes
sub _chain_relationship {
my ($self, $rel) = @_;
my $source = $self->result_source;
- my $attrs = $self->{attrs};
+ my $attrs = { %{$self->{attrs}||{}} };
- my $from = [ @{
- $attrs->{from}
- ||
- [{
- -source_handle => $source->handle,
- -alias => $attrs->{alias},
- $attrs->{alias} => $source->from,
- }]
- }];
+ # we need to take the prefetch the attrs into account before we
+ # ->_resolve_join as otherwise they get lost - captainL
+ my $join = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
- my $seen = { %{$attrs->{seen_join} || {} } };
- my $jpath = ($attrs->{seen_join} && keys %{$attrs->{seen_join}})
- ? $from->[-1][0]{-join_path}
- : [];
+ delete @{$attrs}{qw/join prefetch collapse group_by distinct select as columns +select +as +columns/};
+ my $seen = { %{ (delete $attrs->{seen_join}) || {} } };
- # we need to take the prefetch the attrs into account before we
- # ->_resolve_join as otherwise they get lost - captainL
- my $merged = $self->_merge_attr( $attrs->{join}, $attrs->{prefetch} );
+ my $from;
+ my @force_subq_attrs = qw/offset rows group_by having/;
+
+ if (
+ ($attrs->{from} && ref $attrs->{from} ne 'ARRAY')
+ ||
+ $self->_has_resolved_attr (@force_subq_attrs)
+ ) {
+ # Nuke the prefetch (if any) before the new $rs attrs
+ # are resolved (prefetch is useless - we are wrapping
+ # a subquery anyway).
+ my $rs_copy = $self->search;
+ $rs_copy->{attrs}{join} = $self->_merge_attr (
+ $rs_copy->{attrs}{join},
+ delete $rs_copy->{attrs}{prefetch},
+ );
+
+ $from = [{
+ -source_handle => $source->handle,
+ -alias => $attrs->{alias},
+ $attrs->{alias} => $rs_copy->as_query,
+ }];
+ delete @{$attrs}{@force_subq_attrs, qw/where bind/};
+ $seen->{-relation_chain_depth} = 0;
+ }
+ elsif ($attrs->{from}) { #shallow copy suffices
+ $from = [ @{$attrs->{from}} ];
+ }
+ else {
+ $from = [{
+ -source_handle => $source->handle,
+ -alias => $attrs->{alias},
+ $attrs->{alias} => $source->from,
+ }];
+ }
+
+ my $jpath = ($seen->{-relation_chain_depth})
+ ? $from->[-1][0]{-join_path}
+ : [];
my @requested_joins = $source->_resolve_join(
- $merged,
+ $join,
$attrs->{alias},
$seen,
$jpath,
push @$from, @requested_joins;
- $seen->{-relation_chain_depth} += 0.5;
+ $seen->{-relation_chain_depth}++;
# if $self already had a join/prefetch specified on it, the requested
# $rel might very well be already included. What we do in this case
# the join in question so we could tell it *is* the search_related)
my $already_joined;
-
# we consider the last one thus reverse
for my $j (reverse @requested_joins) {
- if ($rel eq $j->[0]{-join_path}[-1]) {
- $j->[0]{-relation_chain_depth} += 0.5;
+ my ($last_j) = keys %{$j->[0]{-join_path}[-1]};
+ if ($rel eq $last_j) {
+ $j->[0]{-relation_chain_depth}++;
$already_joined++;
last;
}
}
-# alternative way to scan the entire chain - not backwards compatible
-# for my $j (reverse @$from) {
-# next unless ref $j eq 'ARRAY';
-# if ($j->[0]{-join_path} && $j->[0]{-join_path}[-1] eq $rel) {
-# $j->[0]{-relation_chain_depth} += 0.5;
-# $already_joined++;
-# last;
-# }
-# }
-
unless ($already_joined) {
push @$from, $source->_resolve_join(
$rel,
);
}
- $seen->{-relation_chain_depth} += 0.5;
+ $seen->{-relation_chain_depth}++;
- return ($from,$seen);
+ return {%$attrs, from => $from, seen_join => $seen};
}
# too many times we have to do $attrs = { %{$self->_resolved_attrs} }
# build columns (as long as select isn't set) into a set of as/select hashes
unless ( $attrs->{select} ) {
- my @cols = ( ref($attrs->{columns}) eq 'ARRAY' )
- ? @{ delete $attrs->{columns}}
- : (
- ( delete $attrs->{columns} )
- ||
- $source->storage->_order_select_columns(
- $source,
- [ $source->columns ],
- )
- )
- ;
+ my @cols;
+ if ( ref $attrs->{columns} eq 'ARRAY' ) {
+ @cols = @{ delete $attrs->{columns}}
+ } elsif ( defined $attrs->{columns} ) {
+ @cols = delete $attrs->{columns}
+ } else {
+ @cols = $source->columns
+ }
- @colbits = map {
- ( ref($_) eq 'HASH' )
- ? $_
- : {
- (
- /^\Q${alias}.\E(.+)$/
- ? "$1"
- : "$_"
- )
- =>
- (
- /\./
- ? "$_"
- : "${alias}.$_"
- )
- }
- } @cols;
+ for (@cols) {
+ if ( ref $_ eq 'HASH' ) {
+ push @colbits, $_
+ } else {
+ my $key = /^\Q${alias}.\E(.+)$/
+ ? "$1"
+ : "$_";
+ my $value = /\./
+ ? "$_"
+ : "${alias}.$_";
+ push @colbits, { $key => $value };
+ }
+ }
}
# add the additional columns on
- foreach ( 'include_columns', '+columns' ) {
- push @colbits, map {
- ( ref($_) eq 'HASH' )
- ? $_
- : { ( split( /\./, $_ ) )[-1] => ( /\./ ? $_ : "${alias}.$_" ) }
- } ( ref($attrs->{$_}) eq 'ARRAY' ) ? @{ delete $attrs->{$_} } : delete $attrs->{$_} if ( $attrs->{$_} );
+ foreach (qw{include_columns +columns}) {
+ if ( $attrs->{$_} ) {
+ my @list = ( ref($attrs->{$_}) eq 'ARRAY' )
+ ? @{ delete $attrs->{$_} }
+ : delete $attrs->{$_};
+ for (@list) {
+ if ( ref($_) eq 'HASH' ) {
+ push @colbits, $_
+ } else {
+ my $key = ( split /\./, $_ )[-1];
+ my $value = ( /\./ ? $_ : "$alias.$_" );
+ push @colbits, { $key => $value };
+ }
+ }
+ }
}
# start with initial select items
( ref $attrs->{select} eq 'ARRAY' )
? [ @{ $attrs->{select} } ]
: [ $attrs->{select} ];
- $attrs->{as} = (
- $attrs->{as}
- ? (
- ref $attrs->{as} eq 'ARRAY'
- ? [ @{ $attrs->{as} } ]
- : [ $attrs->{as} ]
+
+ if ( $attrs->{as} ) {
+ $attrs->{as} =
+ (
+ ref $attrs->{as} eq 'ARRAY'
+ ? [ @{ $attrs->{as} } ]
+ : [ $attrs->{as} ]
)
- : [ map { m/^\Q${alias}.\E(.+)$/ ? $1 : $_ } @{ $attrs->{select} } ]
- );
+ } else {
+ $attrs->{as} = [ map {
+ m/^\Q${alias}.\E(.+)$/
+ ? $1
+ : $_
+ } @{ $attrs->{select} }
+ ]
+ }
}
else {
}
# now add colbits to select/as
- push( @{ $attrs->{select} }, map { values( %{$_} ) } @colbits );
- push( @{ $attrs->{as} }, map { keys( %{$_} ) } @colbits );
+ push @{ $attrs->{select} }, map values %{$_}, @colbits;
+ push @{ $attrs->{as} }, map keys %{$_}, @colbits;
- my $adds;
- if ( $adds = delete $attrs->{'+select'} ) {
+ if ( my $adds = delete $attrs->{'+select'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push(
- @{ $attrs->{select} },
- map { /\./ || ref $_ ? $_ : "${alias}.$_" } @$adds
- );
+ push @{ $attrs->{select} },
+ map { /\./ || ref $_ ? $_ : "$alias.$_" } @$adds;
}
- if ( $adds = delete $attrs->{'+as'} ) {
+ if ( my $adds = delete $attrs->{'+as'} ) {
$adds = [$adds] unless ref $adds eq 'ARRAY';
- push( @{ $attrs->{as} }, @$adds );
+ push @{ $attrs->{as} }, @$adds;
}
- $attrs->{from} ||= [ {
+ $attrs->{from} ||= [{
-source_handle => $source->handle,
-alias => $self->{attrs}{alias},
$self->{attrs}{alias} => $source->from,
- } ];
+ }];
if ( $attrs->{join} || $attrs->{prefetch} ) {
- $self->throw_exception ('join/prefetch can not be used with a literal scalarref {from}')
+ $self->throw_exception ('join/prefetch can not be used with a custom {from}')
if ref $attrs->{from} ne 'ARRAY';
my $join = delete $attrs->{join} || {};
$join,
$alias,
{ %{ $attrs->{seen_join} || {} } },
- ($attrs->{seen_join} && keys %{$attrs->{seen_join}})
+ ( $attrs->{seen_join} && keys %{$attrs->{seen_join}})
? $attrs->{from}[-1][0]{-join_path}
: []
,
# 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}) {
- $attrs->{group_by} ||= [ grep { !ref($_) || (ref($_) ne 'HASH') } @{$attrs->{select}} ];
+ if ($attrs->{group_by}) {
+ 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}} ];
+
+ # 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}});
+
+ my $storage = $self->result_source->schema->storage;
+
+ 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;
+ }
+ }
+ }
}
$attrs->{collapse} ||= {};
my $prefetch_ordering = [];
- my $join_map = $self->_joinpath_aliases ($attrs->{from}, $attrs->{seen_join});
+ # this is a separate structure (we don't look in {from} directly)
+ # as the resolver needs to shift things off the lists to work
+ # properly (identical-prefetches on different branches)
+ my $join_map = {};
+ if (ref $attrs->{from} eq 'ARRAY') {
+
+ my $start_depth = $attrs->{seen_join}{-relation_chain_depth} || 0;
+
+ for my $j ( @{$attrs->{from}}[1 .. $#{$attrs->{from}} ] ) {
+ next unless $j->[0]{-alias};
+ next unless $j->[0]{-join_path};
+ next if ($j->[0]{-relation_chain_depth} || 0) < $start_depth;
+
+ my @jpath = map { keys %$_ } @{$j->[0]{-join_path}};
+
+ my $p = $join_map;
+ $p = $p->{$_} ||= {} for @jpath[ ($start_depth/2) .. $#jpath]; #only even depths are actual jpath boundaries
+ push @{$p->{-join_aliases} }, $j->[0]{-alias};
+ }
+ }
my @prefetch =
$source->_resolve_prefetch( $prefetch, $alias, $join_map, $prefetch_ordering, $attrs->{collapse} );
# even though it doesn't make much sense, this is what pre 081xx has
# been doing
if (my $page = delete $attrs->{page}) {
- $attrs->{offset} =
+ $attrs->{offset} =
($attrs->{rows} * ($page - 1))
+
($attrs->{offset} || 0)
return $self->{_attrs} = $attrs;
}
-sub _joinpath_aliases {
- my ($self, $fromspec, $seen) = @_;
-
- my $paths = {};
- return $paths unless ref $fromspec eq 'ARRAY';
-
- my $cur_depth = $seen->{-relation_chain_depth} || 0;
-
- if (int ($cur_depth) != $cur_depth) {
- $self->throw_exception ("-relation_chain_depth is not an integer, something went horribly wrong ($cur_depth)");
- }
-
- for my $j (@$fromspec) {
-
- next if ref $j ne 'ARRAY';
- next if ($j->[0]{-relation_chain_depth} || 0) < $cur_depth;
-
- my $jpath = $j->[0]{-join_path};
-
- my $p = $paths;
- $p = $p->{$_} ||= {} for @{$jpath}[$cur_depth .. $#$jpath];
- push @{$p->{-join_aliases} }, $j->[0]{-alias};
- }
-
- return $paths;
-}
-
sub _rollout_attr {
my ($self, $attr) = @_;
sub _calculate_score {
my ($self, $a, $b) = @_;
+ if (defined $a xor defined $b) {
+ return 0;
+ }
+ elsif (not defined $a) {
+ return 1;
+ }
+
if (ref $b eq 'HASH') {
my ($b_key) = keys %{$b};
if (ref $a eq 'HASH') {
sub throw_exception {
my $self=shift;
+
if (ref $self && $self->_source_handle->schema) {
$self->_source_handle->schema->throw_exception(@_)
- } else {
- croak(@_);
}
-
+ else {
+ DBIx::Class::Exception->throw(@_);
+ }
}
# XXX: FIXME: Attributes docs need clearing up
=back
-Which column(s) to order the results by.
+Which column(s) to order the results by.
[The full list of suitable values is documented in
L<SQL::Abstract/"ORDER BY CLAUSES">; the following is a summary of
select => [
'name',
{ count => 'employeeid' },
- { sum => 'salary' }
+ { max => { length => 'name' }, -as => 'longest_name' }
]
});
-When you use function/stored procedure names and do not supply an C<as>
-attribute, the column names returned are storage-dependent. E.g. MySQL would
-return a column named C<count(employeeid)> in the above example.
+ # Equivalent SQL
+ SELECT name, COUNT( employeeid ), MAX( LENGTH( name ) ) AS longest_name FROM employee
+
+B<NOTE:> You will almost always need a corresponding L</as> attribute when you
+use L</select>, to instruct DBIx::Class how to store the result of the column.
+Also note that the L</as> attribute has nothing to do with the SQL-side 'AS'
+identifier aliasing. You can however alias a function, so you can use it in
+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.
=head2 +select
=over 4
Indicates additional columns to be selected from storage. Works the same as
-L</select> but adds columns to the selection.
+L</select> but adds columns to the default selection, instead of specifying
+an explicit list.
=back
=back
-Indicates column names for object inflation. That is, C<as>
-indicates the name that the column can be accessed as via the
-C<get_column> method (or via the object accessor, B<if one already
-exists>). It has nothing to do with the SQL code C<SELECT foo AS bar>.
-
-The C<as> attribute is used in conjunction with C<select>,
-usually when C<select> contains one or more function or stored
-procedure names:
+Indicates column 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
+with the same name already exists>) as shown below. The L</as> attribute has
+B<nothing to do> with the SQL-side C<AS>. See L</select> for details.
$rs = $schema->resultset('Employee')->search(undef, {
select => [
'name',
- { count => 'employeeid' }
+ { count => 'employeeid' },
+ { max => { length => 'name' }, -as => 'longest_name' }
],
- as => ['name', 'employee_count'],
+ as => [qw/
+ name
+ employee_count
+ max_name_length
+ /],
});
- my $employee = $rs->first(); # get the first Employee
-
If the object against which the search is performed already has an accessor
matching a column name specified in C<as>, the value can be retrieved using
the accessor as normal:
You can create your own accessors if required - see
L<DBIx::Class::Manual::Cookbook> for details.
-Please note: This will NOT insert an C<AS employee_count> into the SQL
-statement produced, it is used for internal access only. Thus
-attempting to use the accessor in an C<order_by> clause or similar
-will fail miserably.
-
-To get around this limitation, you can supply literal SQL to your
-C<select> attibute that contains the C<AS alias> text, eg:
-
- select => [\'myfield AS alias']
-
=head2 join
=over 4
C<prefetch> can be used with the following relationship types: C<belongs_to>,
C<has_one> (or if you're using C<add_relationship>, any relationship declared
with an accessor type of 'single' or 'filter'). A more complex example that
-prefetches an artists cds, the tracks on those cds, and the tags associted
+prefetches an artists cds, the tracks on those cds, and the tags associated
with that artist is given below (assuming many-to-many from artists to tags):
my $rs = $schema->resultset('Artist')->search(
=over 4
-=item *
+=item *
Prefetch uses the L</cache> to populate the prefetched relationships. This
may or may not be what you want.
-=item *
+=item *
If you specify a condition on a prefetched relationship, ONLY those
rows that match the prefetched condition will be fetched into that relationship.
=back
-Specifes the maximum number of rows for direct retrieval or the number of
+Specifies the maximum number of rows for direct retrieval or the number of
rows per page if the page attribute or method is used.
=head2 offset
=back
-Set to 1 to group by all columns.
+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.
=head2 where
# only return rows WHERE deleted IS NULL for all searches
__PACKAGE__->resultset_attributes({ where => { deleted => undef } }); )
-Can be overridden by passing C<{ where => undef }> as an attribute
-to a resulset.
+Can be overridden by passing C<< { where => undef } >> as an attribute
+to a resultset.
=back
For more examples of using these attributes, see
L<DBIx::Class::Manual::Cookbook>.
-=head2 from
-
-=over 4
-
-=item Value: \@from_clause
-
-=back
-
-The C<from> attribute gives you manual control over the C<FROM> clause of SQL
-statements generated by L<DBIx::Class>, allowing you to express custom C<JOIN>
-clauses.
-
-NOTE: Use this on your own risk. This allows you to shoot off your foot!
-
-C<join> will usually do what you need and it is strongly recommended that you
-avoid using C<from> unless you cannot achieve the desired result using C<join>.
-And we really do mean "cannot", not just tried and failed. Attempting to use
-this because you're having problems with C<join> is like trying to use x86
-ASM because you've got a syntax error in your C. Trust us on this.
-
-Now, if you're still really, really sure you need to use this (and if you're
-not 100% sure, ask the mailing list first), here's an explanation of how this
-works.
-
-The syntax is as follows -
-
- [
- { <alias1> => <table1> },
- [
- { <alias2> => <table2>, -join_type => 'inner|left|right' },
- [], # nested JOIN (optional)
- { <table1.column1> => <table2.column2>, ... (more conditions) },
- ],
- # More of the above [ ] may follow for additional joins
- ]
-
- <table1> <alias1>
- JOIN
- <table2> <alias2>
- [JOIN ...]
- ON <table1.column1> = <table2.column2>
- <more joins may follow>
-
-An easy way to follow the examples below is to remember the following:
-
- Anything inside "[]" is a JOIN
- Anything inside "{}" is a condition for the enclosing JOIN
-
-The following examples utilize a "person" table in a family tree application.
-In order to express parent->child relationships, this table is self-joined:
-
- # Person->belongs_to('father' => 'Person');
- # Person->belongs_to('mother' => 'Person');
-
-C<from> can be used to nest joins. Here we return all children with a father,
-then search against all mothers of those children:
-
- $rs = $schema->resultset('Person')->search(
- undef,
- {
- alias => 'mother', # alias columns in accordance with "from"
- from => [
- { mother => 'person' },
- [
- [
- { child => 'person' },
- [
- { father => 'person' },
- { 'father.person_id' => 'child.father_id' }
- ]
- ],
- { 'mother.person_id' => 'child.mother_id' }
- ],
- ]
- },
- );
-
- # Equivalent SQL:
- # SELECT mother.* FROM person mother
- # JOIN (
- # person child
- # JOIN person father
- # ON ( father.person_id = child.father_id )
- # )
- # ON ( mother.person_id = child.mother_id )
-
-The type of any join can be controlled manually. To search against only people
-with a father in the person table, we could explicitly use C<INNER JOIN>:
-
- $rs = $schema->resultset('Person')->search(
- undef,
- {
- alias => 'child', # alias columns in accordance with "from"
- from => [
- { child => 'person' },
- [
- { father => 'person', -join_type => 'inner' },
- { 'father.id' => 'child.father_id' }
- ],
- ]
- },
- );
-
- # Equivalent SQL:
- # SELECT child.* FROM person child
- # INNER JOIN person father ON child.father_id = father.id
-
-You can select from a subquery by passing a resultset to from as follows.
-
- $schema->resultset('Artist')->search(
- undef,
- { alias => 'artist2',
- from => [ { artist2 => $artist_rs->as_query } ],
- } );
-
- # and you'll get sql like this..
- # SELECT artist2.artistid, artist2.name, artist2.rank, artist2.charfield FROM
- # ( SELECT me.artistid, me.name, me.rank, me.charfield FROM artists me ) artist2
-
-If you need to express really complex joins, you
-can supply literal SQL to C<from> via a scalar reference. In this case
-the contents of the scalar will replace the table name associated with the
-resultsource.
-
-WARNING: This technique might very well not work as expected on chained
-searches - you have been warned.
-
- # Assuming the Event resultsource is defined as:
-
- MySchema::Event->add_columns (
- sequence => {
- data_type => 'INT',
- is_auto_increment => 1,
- },
- location => {
- data_type => 'INT',
- },
- type => {
- data_type => 'INT',
- },
- );
- MySchema::Event->set_primary_key ('sequence');
-
- # This will get back the latest event for every location. The column
- # selector is still provided by DBIC, all we do is add a JOIN/WHERE
- # combo to limit the resultset
-
- $rs = $schema->resultset('Event');
- $table = $rs->result_source->name;
- $latest = $rs->search (
- undef,
- { from => \ "
- (SELECT e1.* FROM $table e1
- JOIN $table e2
- ON e1.location = e2.location
- AND e1.sequence < e2.sequence
- WHERE e2.sequence is NULL
- ) me",
- },
- );
-
- # Equivalent SQL (with the DBIC chunks added):
-
- SELECT me.sequence, me.location, me.type FROM
- (SELECT e1.* FROM events e1
- JOIN events e2
- ON e1.location = e2.location
- AND e1.sequence < e2.sequence
- WHERE e2.sequence is NULL
- ) me;
-
=head2 for
=over 4