关键词: 主动数据库, 规则分析, 活化路径, 增强条件公式, 可终止性

Abstract:

Termination decision in active database becomes a focus for many researchers. Existing methods based on triggering and activation graphs do not consider whether all rules in a triggering cycle can be executed at the same execution sequence. Existing methods based on logical formula, where only those nonupdatable or finitely updatable variables can be represented, cannot conclude termination if a rule set contains only those cycles that can be executed in a finite number of times. To solve this problem, the concept of the execution sequence of a triggering cycle and the method to construct an enhanced formula including updatable variables are proposed. Many termination cases that cannot be determined by previous methods can be detected by the proposed solution, whose correctness and termination are proved.
      

Key words: active database;rule analysis;activation path;enhanced conditional formula;termination