# collect relationships. currently done in one big block at the end;
# may need to move this upwards if people want automatic completion of
# relationships, i.e. deliver referenced objects like we do with ways...
- relations = Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
- "e.visible=1 and " +
- "em.id = e.id and em.member_type='node' and em.member_id in (#{visible_nodes.keys.join(',')})")
- relations += Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
- "e.visible=1 and " +
- "em.id = e.id and em.member_type='way' and em.member_id in (#{way_ids.join(',')})")
+ relations = Array.new
+ if visible_nodes.length > 0
+ relations += Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
+ "e.visible=1 and " +
+ "em.id = e.id and em.member_type='node' and em.member_id in (#{visible_nodes.keys.join(',')})")
+ end
+ if way_ids.length > 0
+ relations += Relation.find_by_sql("select e.* from current_relations e,current_relation_members em where " +
+ "e.visible=1 and " +
+ "em.id = e.id and em.member_type='way' and em.member_id in (#{way_ids.join(',')})")
+ end
# we do not normally return the "other" partners referenced by an relation,
# e.g. if we return a way A that is referenced by relation X, and there's
# another way B also referenced, that is not returned. But we do make