Research Of Rule Mechanism For Active DBMS

A significant drawback in active database application lies in the development of correct rule application.It is very difficult in general to predict how a set of active database rules will behave.but active behave of active databse only through rule mechanism.At the beginning of the paper,we introduce research background,development and current situation of active database ,and active function subsystem and active database structure.On the base of the previous main memory DBMS,the rule subsystem, which is used to implement the DBMS's active function, has been introduced.Based on the techniques of main memory database, we have designed and realized the rule subsystem,the rule expression, rule memory structure,rule trigger mechanism,rule execution mechanism , events detection mechanism ,transaction analyzing and conversion mechanism from the rule to statement so as to implement the active function of the system. We also discuss cascade trigger ,rule termination of the active rule set.