An agent-based approach for extending the trigger capability of Oracle.

摘要

Triggers provided by a DBMS are primitive and their ability to monitor and react to situations automatically is very limited. ECA (or event-condition-action) rules have been proposed as an expressive way to support active capability. Triggers, currently supported by a relational DBMS, form a subset of generally accepted active capability. The events in ECA rules can be quite expressive and include composite events as well as parameter contexts and coupling modes. Snoop, developed as an event specification language provides a number of event operators.; In this thesis, we develop an agent-based approach for supporting full active capability using ECA rules for Oracle. This approach allows us to use the native trigger capability and augment the DBMS with triggers on composite events, parameter contexts, and coupling modes. The approach is general in that it can be used for other relational DBMSs as well. The advantage of this approach is that it transparently supports active capability and preserves compatibility with existing applications.