多数据库系统中的一致性维护

在多数据库环境中存在着全局事务和局部事务，它们必须相互协作，从而为应用程序提供一致性的数据。为了维护多数据库系统（MDBS）的一致性，提出一种事务管理机制。该机制基于扩展事务的原理，对全局子事务和局部事务进行扩展，并为各个局部数据库引进一些控制表。局部数据库管理系统（LDBMS）和局部数据库和控制表之上执行扩展务，这些扩展事务负一局可串行性及事务的恢复。由于它不依赖于LDBMS的各种特征，因此该方法易于实现，是实用的。

MAINTAINING CONSISTENCY IN MULTIDATABASE SYSTEMS

In a MDBS environment, there are two kinds of transactions: global transactions and local transactions. They must cooperate to provide all applications with consistent data. In order to maintain consistency in multidatabase systems, a transaction management mechanism is proposed, which is based on the principle of extended transactions. The presented method extends global transactions and local transactions. And each component database is extended by some control tables. The extended transactions are executed by the LDBMS on the local database and the specially generated control tables. These extended transactions are responsible for the global serializability and recovery of transactions. The solution is easy to implement because it is independent of all characters of LDBMS.