compared to the relational database systems, the rtdbs have three distinguishing features : the requirement of temporal constraints on data, the requirement of timing constraints on transactions, and the requirement that certain executions exhibit predictable timing behavior 与传统关系数据库相比,实时数据库具有三个特征:数据的时态一致性、事务的时态一致性、实时事务执行时必须具有可预测性。