Extensibility is one of the mayor benefits of object-relational database management systems. We have used this system property to implement a StateMachine Module inside an object-relational database management system. The module allows the checking of dynamic integrity constraints as well as the execution of active behavior specified with the UML. Our approach demonstrates that extensibility can effectively be applied to integrate such dynamic aspects specified with UML statecharts into an object-relational database management system. 1 Motivation Object-relational database management systems (ORDBMS) enable us to extend their off-the-shelf functionality by self-developed extension modules [6]. This allows us to adopt an ORDBMS to the needs of several application domains. Our demonstration illustrates how this feature can be exploited to equip an ORDBMS with a module which handles dynamic aspects inside the database system. In our SERUM project [3], we use an object-oriented specifica...