+=item unique_singles
+
+Meet exciting and unique singles using this method!
+
+This method returns a list of column names that are indexed with their own,
+unique, non-compond (that's the "single" part) indices.
+
+=cut
+
+sub unique_singles {
+ my $self = shift;
+ my %indices = $self->indices;
+
+ map { ${ $indices{$_}->columns }[0] }
+ grep { $indices{$_}->unique && scalar(@{$indices{$_}->columns}) == 1 }
+ keys %indices;
+}
+