VITAL: A Visual Tool for Analysis of Rules Behaviour in Active Databases

Although active rules are used more and more in different IS applications, designing a coherent set of active rules is not a trivial task. Thus, it is important to provide tools to help the designer in the definition of a correct set of active rules. In this paper, we propose a toolbox which assists the designer in defining, tracing, debugging and understanding the behaviour of a set of active rules. This set of facilities is packaged in a toolbox in order to be used both during the design process, independently of any rule processor, and after the compiling process, depending on a specific rule processor. The former corresponds to a logical validation while the later corresponds to an effective validation with respect to the features of a specific DBMS (e.g. coupling modes, event interception). The toolbox includes various tools such as (i) a static analyser for a set of rules, which portrays the activation graph and its possible cycles, (ii) the step by step simulator of rule execution, (iii) a graphical interface with navigation and browsing facilities, (iv) and statistical information on the database evolution. This set of tools can be considered as a pragmatic approach to the complex problem of termination and confluence, to which the theoretical approaches have not yet provided an acceptable solution.