Expressiveness and complexity of active databases

The expressiveness and complexity of several active database prototypes are formally studied. First, a generic framework for the specification of active databases is developed. This factors out the common aspects of the prototypes considered, and allows studying various active database features independently of any specific prototype. Furthermore, each of the prototypes can be specified by specializing certain parameters of the framework. The prototypes considered are ARDL, HiPAC, Postgres, Starburst, and Sybase. Using their formal specifications, the prototypes are compared to each other with respect to expressive power. The results provide insight into the programming paradigm of active databases, the interplay of various features, and their impact on expressiveness and complexity.