A crucial requirement for active database systems is the ability to analyse
the behaviour of active rules.  A particularly important type of analysis is
termination analysis.  We define a framework for modelling the execution of
active rules, based on abstract interpretation.  Specific methods for
termination analysis are modelled by defining them as specific
approximations within the framework.  The correctness of a method can be
established by proving two generic requirements provided by the framework.
This affords the opportunity to compare and verify existing methods for
termination analysis of active rules, and also to develop new ones.