An active database system is a DBMS endowed with active rules, i.e. stored procedures activated by the system when specific events occur. The processing of active rules is characterized by two important properties: termination and confluence. We say that the processing of a set of active rules terminates if, given any initial active database state, the execution of the rules does not continue indefinitely; it is confluent if, for any active database state, the final state does not depend on the order of execution of the rules. Finding sufficient conditions is a nontrivial problem and the lack of a structured theory for the design of a system of active rules makes the analysis of the two properties more difficult. In this work, we see ECA rules as an evolution of deductive rules: we translate the active rules into logical clauses, taking into account the system's execution semantics, then we try to transfer to the active process the known results about termination and determinism available in the literature for deductive rules: sufficient conditions for the two properties of the ECA rules to hold can be found.
Using the properties of datalog to prove termination and confluence in active databasesRules in Database Systems
COMAI, SARA;TANCA, LETIZIA
1997-01-01
Abstract
An active database system is a DBMS endowed with active rules, i.e. stored procedures activated by the system when specific events occur. The processing of active rules is characterized by two important properties: termination and confluence. We say that the processing of a set of active rules terminates if, given any initial active database state, the execution of the rules does not continue indefinitely; it is confluent if, for any active database state, the final state does not depend on the order of execution of the rules. Finding sufficient conditions is a nontrivial problem and the lack of a structured theory for the design of a system of active rules makes the analysis of the two properties more difficult. In this work, we see ECA rules as an evolution of deductive rules: we translate the active rules into logical clauses, taking into account the system's execution semantics, then we try to transfer to the active process the known results about termination and determinism available in the literature for deductive rules: sufficient conditions for the two properties of the ECA rules to hold can be found.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
