my $unique_query = $self->_build_unique_query($input_query, \@unique_cols);
$query = $self->_add_alias($unique_query, $alias);
}
+ elsif ($self->{attrs}{accessor} and $self->{attrs}{accessor} eq 'single') {
+ # This means that we got here after a merger of relationship conditions
+ # 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
+ # relationship
+ }
else {
my @unique_queries = $self->_unique_queries($input_query, $attrs);
$query = @unique_queries
}
# Run the query
- if (keys %$attrs) {
- my $rs = $self->search($query, $attrs);
- if (keys %{$rs->_resolved_attrs->{collapse}}) {
- my $row = $rs->next;
- carp "Query returned more than one row" if $rs->next;
- return $row;
- }
- else {
- return $rs->single;
- }
+ my $rs = $self->search ($query, $attrs);
+ if (keys %{$rs->_resolved_attrs->{collapse}}) {
+ my $row = $rs->next;
+ carp "Query returned more than one row" if $rs->next;
+ return $row;
}
else {
- if (keys %{$self->_resolved_attrs->{collapse}}) {
- my $rs = $self->search($query);
- my $row = $rs->next;
- carp "Query returned more than one row" if $rs->next;
- return $row;
- }
- else {
- return $self->single($query);
- }
+ return $rs->single;
}
}
Query returned more than one row
-In this case, you should be using L</first> or L</find> instead, or if you really
+In this case, you should be using L</next> or L</find> instead, or if you really
know what you are doing, use the L</rows> attribute to explicitly limit the size
of the resultset.
+This method will also throw an exception if it is called on a resultset prefetching
+has_many, as such a prefetch implies fetching multiple rows from the database in
+order to assemble the resulting object.
+
=back
=cut
my $attrs = $self->_resolved_attrs_copy;
+ if (keys %{$attrs->{collapse}}) {
+ $self->throw_exception(
+ 'single() can not be used on resultsets prefetching has_many. Use find( \%cond ) or next() instead'
+ );
+ }
+
if ($where) {
if (defined $attrs->{where}) {
$attrs->{where} = {
return $self->search(@_)->count if @_ and defined $_[0];
return scalar @{ $self->get_cache } if $self->get_cache;
- my $meth = $self->_has_resolved_attr (qw/collapse group_by/)
- ? 'count_grouped'
- : 'count'
- ;
-
my $attrs = $self->_resolved_attrs_copy;
+
+ # this is a little optimization - it is faster to do the limit
+ # adjustments in software, instead of a subquery
+ my $rows = delete $attrs->{rows};
+ my $offset = delete $attrs->{offset};
+
+ my $crs;
+ if ($self->_has_resolved_attr (qw/collapse group_by/)) {
+ $crs = $self->_count_subq_rs ($attrs);
+ }
+ else {
+ $crs = $self->_count_rs ($attrs);
+ }
+ my $count = $crs->next;
+
+ $count -= $offset if $offset;
+ $count = $rows if $rows and $rows < $count;
+ $count = 0 if ($count < 0);
+
+ return $count;
+}
+
+=head2 count_rs
+
+=over 4
+
+=item Arguments: $cond, \%attrs??
+
+=item Return Value: $count_rs
+
+=back
+
+Same as L</count> but returns a L<DBIx::Class::ResultSetColumn> object.
+This can be very handy for subqueries:
+
+ ->search( { amount => $some_rs->count_rs->as_query } )
+
+As with regular resultsets the SQL query will be executed only after
+the resultset is accessed via L</next> or L</all>. That would return
+the same single value obtainable via L</count>.
+
+=cut
+
+sub count_rs {
+ my $self = shift;
+ return $self->search(@_)->count_rs if @_;
+
+ # this may look like a lack of abstraction (count() does about the same)
+ # but in fact an _rs *must* use a subquery for the limits, as the
+ # 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;
+ }
+ else {
+ return $self->_count_rs;
+ }
+}
+
+#
+# returns a ResultSetColumn object tied to the count query
+#
+sub _count_rs {
+ my ($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 a count
+ delete $tmp_attrs->{$_} for (qw/select as rows offset order_by record_filter/);
+
+ # overwrite the selector (supplied by the storage)
+ $tmp_attrs->{select} = $rsrc->storage->_count_select ($rsrc, $tmp_attrs);
+ $tmp_attrs->{as} = 'count';
+
+ my $tmp_rs = $rsrc->resultset_class->new($rsrc, $tmp_attrs)->get_column ('count');
+
+ return $tmp_rs;
+}
+
+#
+# same as above but uses a subquery
+#
+sub _count_subq_rs {
+ my ($self, $attrs) = @_;
+
my $rsrc = $self->result_source;
+ $attrs ||= $self->_resolved_attrs_copy;
+
+ my $sub_attrs = { %$attrs };
+
+ # these can not go in the subquery, and there is no point of ordering it
+ delete $sub_attrs->{$_} for qw/collapse select as order_by/;
+
+ # if we prefetch, we group_by primary keys only as this is what we would get out of the rs via ->next/->all
+ # clobber old group_by regardless
+ if ( keys %{$attrs->{collapse}} ) {
+ $sub_attrs->{group_by} = [ map { "$attrs->{alias}.$_" } ($rsrc->primary_columns) ]
+ }
+
+ $sub_attrs->{select} = $rsrc->storage->_subq_count_select ($rsrc, $sub_attrs);
+
+ # 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,
+ }];
+
+ # the subquery replaces this
+ delete $attrs->{$_} for qw/where bind collapse group_by having having_bind rows offset/;
- return $rsrc->storage->$meth ($rsrc, $attrs);
+ return $self->_count_rs ($attrs);
}
+
sub _bool {
return 1;
}
to insert the data, as this is a faster method.
Otherwise, each set of data is inserted into the database using
-L<DBIx::Class::ResultSet/create>, and a arrayref of the resulting row
-objects is returned.
+L<DBIx::Class::ResultSet/create>, and the resulting objects are
+accumulated into an array. The array itself, or an array reference
+is returned depending on scalar or list context.
Example: Assuming an Artist Class that has many CDs Classes relating:
foreach my $item (@$data) {
push(@created, $self->create($item));
}
- return @created;
+ return wantarray ? @created : \@created;
} else {
my ($first, @rest) = @$data;
=back
$cd->cd_to_producer->find_or_create({ producer => $producer },
- { key => 'primary });
+ { key => 'primary' });
Tries to find a record based on its primary key or unique constraints; if none
is found, creates one and returns that instead.
$self->{related_resultsets} ||= {};
return $self->{related_resultsets}{$rel} ||= do {
- my $rel_obj = $self->result_source->relationship_info($rel);
+ my $rel_info = $self->result_source->relationship_info($rel);
$self->throw_exception(
"search_related: result source '" . $self->result_source->source_name .
"' has no such relationship $rel")
- unless $rel_obj;
+ unless $rel_info;
my ($from,$seen) = $self->_resolve_from($rel);
# with a relation_chain_depth less than the depth of the
# current prefetch is not considered)
sub _resolve_from {
- my ($self, $extra_join) = @_;
+ my ($self, $rel) = @_;
my $source = $self->result_source;
my $attrs = $self->{attrs};
++$seen->{-relation_chain_depth};
- push @$from, $source->_resolve_join($extra_join, $attrs->{alias}, $seen);
+ push @$from, $source->_resolve_join($rel, $attrs->{alias}, $seen);
++$seen->{-relation_chain_depth};
$self->{attrs}{alias} => $source->from,
} ];
- if ( exists $attrs->{join} || exists $attrs->{prefetch} ) {
+ if ( $attrs->{join} || $attrs->{prefetch} ) {
+
+ $self->throw_exception ('join/prefetch can not be used with a literal scalarref {from}')
+ if ref $attrs->{from} ne 'ARRAY';
+
my $join = delete $attrs->{join} || {};
if ( defined $attrs->{prefetch} ) {
$join = $self->_merge_attr( $join, $attrs->{prefetch} );
-
}
$attrs->{from} = # have to copy here to avoid corrupting the original
[
- @{ $attrs->{from} },
- $source->_resolve_join(
- $join, $alias, { %{ $attrs->{seen_join} || {} } }
- )
+ @{ $attrs->{from} },
+ $source->_resolve_join(
+ $join, $alias, { %{ $attrs->{seen_join} || {} } }
+ )
];
-
}
if ( $attrs->{order_by} ) {
# Although this is needed only if the order_by is not defined, it is
# actually cheaper to just populate this rather than properly examining
# order_by (stuf like [ {} ] and the like)
- $attrs->{_virtual_order_by} = [ $self->result_source->primary_columns ];
-
+ my $prefix = $alias . ($source->schema->storage->sql_maker->{name_sep} || '.');
+ $attrs->{_virtual_order_by} = [
+ map { $prefix . $_ } ($source->primary_columns)
+ ];
$attrs->{collapse} ||= {};
if ( my $prefetch = delete $attrs->{prefetch} ) {
identical to creating a non-pages resultset and then calling ->page($page)
on it.
-If L<rows> attribute is not specified it defualts to 10 rows per page.
+If L<rows> attribute is not specified it defaults to 10 rows per page.
When you have a paged resultset, L</count> will only return the number
of rows in the page. To get the total, use the L</pager> and call
projects / dbsrgits/DBIx-Class.git / blobdiff