Immediate materialized view maintenance with transactional consistency is highly desirable to support real-time decision making. Nevertheless, due to high deadlock rates, such maintenance can cause significant performance degradation in the database system. To increase concurrency during such maintenance, we previously proposed the V locking protocol for materialized aggregate join views and showed how to implement it on hash indices. In this paper, we address the thorny problem of implementing the V locking protocol on B-tree indices. We also formally prove that our techniques are both necessary and sufficient to ensure correctness (serializability).