INCREMENTAL EVALUATION OF COMPLEX EVENT-CONDITION-ACTION RULES IN A DATABASE SYSTEM

In the scenario in which a rule set is defined for composite events, instances of the associated primitive events are added to a database-centric rules engine one at a time. Rules that rely on these events fire the corresponding actions when instances of all the corresponding primitive events are detected. Intermediate states of the rule evaluations are persistently stored in the database, thereby avoiding repeated evaluation of portions of rules and supporting efficient incremental evaluation of the rules. The rules defined within a rule set could vary significantly, using various rule condition language constructs such as “any” and negation constructs. The state information generated from evaluating the rules belonging to a single rule set is all stored in a single relational table and managed using direct SQL and DML commands.