Current systems that publish relational data as XML views are {\em passive} in the sense that they can only respond to user-initiated queries over the XML views. In this paper, we propose an {\em active} system whereby users can place triggers on (unmaterialized) XML views of relational data. In this architecture, we present scalable and efficient techniques for processing triggers over XML views by leveraging existing support for SQL triggers in commercial relational databases. We have implemented our proposed techniques in the context of the Quark system built on top of IBM DB2. Our performance results indicate that our proposed techniques are a feasible approach to supporting triggers over XML views of relational data.