Composite Event Speci cation in Active Database Systems: A Petri Nets Approach
نویسندگان
چکیده
Event detection is the rst and the most important step for Event-Condition-Action (ECA) rule execution in active database systems. Composite event detection is not easy for most existing active database systems. In this paper, a Conditional Colored Petri Net model (CCPN) is proposed for composite events speci cation and detection. Composite events are detected by checking composite transition enabling and verifying the temporal condition attached on the transition. On the other hand, rule execution are realized by verifying rule transition enabling and verifying the rule condition attached on the transition. In this way, both composite event detection and ECA rule execution are integrated in the same CCPN model. Furthermore, examples and implementation issues are discussed. Comparisons show that CCPN is a general model for active database system, and it can be used as an independent engine in many active database systems.
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