Eric N. Hanson

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This paper describes testing of rule conditions and execution of rule actions in Ariel active DBMS. The Ariel rule system is tightly coupled with query and update processing. Ariel rules can have conditions based on a mix of patterns, events, and transitions. For testing rule conditions, Ariel makes use of a discrimination network composed of a special data(More)
Current database trigger systems have extremely limited scalability. This paper proposes a way to develop a truly scalable trigger system. Scalability to large numbers of triggers is achieved with a trigger cache to use main memory effectively, and a memory-conserving selection predicate index based on the use of unique expression formats called expression(More)
Forward-chaining rule systems must test each newly asserted fact against a collection of predicates to find those rules that match the fact. Expert system rule engines use a simple combination of hashing and sequential search for this matching. We introduce an algorithm for finding the matching predicates that is more efficient than the standard algorithm(More)
A new, eecient selection predicate indexing scheme for active database systems is introduced. The selection predicate index proposed uses an interval index on an attribute of a relation or object collection when one or more rule condition clauses are deened on that attribute. The selection predicate index uses a new type of interval index called the(More)
Integrating a production rules facility into a database system provides a uniform mechanism for a number of advanced database features including integrity constraint enforcement, derived data maintenance, triggers, alerters, protection, version control, and others. In addition, a database system with rule processing capabilities provides a useful platform(More)
This paper explains the rule subsystem that is being implemented in the POSTGRES DBMS. It is novel in sev eral ways. First, it gives to users the capability of defining rules as well as data to a DBMS. Moreover, depending on the scope of each rule defined, optimization is handled differently. This leads to good performance both in the case that there are(More)
The design and implementation strategy for Ariel, A DBMS with a built-in production rule system (a trigger system), is described. Ariel is being built with the EXODUS database tool kit. The query language of Ariel is a subset of POSTQUEL extended with a new rule language. Effort is focussed on integrating the rule system with transaction processing, and(More)
The conventional way to process commands for relational views is to use query modification to translate the commands into ones on the base relations. An alternative approach has been proposed recently, whereby materialized copies of views are kept, and incrementally updated immediately after each modification of the database. A related scheme exists, in(More)