Coupling Efficiency with Coupling Modes in Active Databases Proofs of lemmas and theorems.pdf

Coupling Eciency with Coupling Modes in ActiveDatabasesProofs of lemmas and theorems Avigdor GalDepartment of Computer ScienceUniversity of TorontoyAbstractThe paper presents a general framework for handling coupling modes in activedatabases and discusses the inter-relationships between a set of coupling modes ofan application and transaction eciency. While the major role of coupling modes inactive databases is to reduce ambiguous interpretation of transactions, coupling modescan aect the transactions eciency as well. Therefore, a default coupling mode isdened for each rule in a given application, based on eciency considerations. Thismechanism enables a designer of an application to consider eciency while determiningcoupling modes, and base the coupling modes decision on theoretical grounds. Thisissue is particularly important in work ow management, where use of active databasesin work ows on the one hand, and the failure of commercial products to supportapplications with high-throughput work ows on the other hand, requires an ecientexecution process. Thus, this framework is part of CODES, a COntrol and DataEngineering of Systems, which is an extended design tool for work ows.keywords: active databases, coupling modes1 The model We use a generic data model where an object is generically dened as an instance ofa class or a tuple in a relation and a property is dened as an attribute in the object-oriented model and a column in the relational model. The term class denes eitherThis paper is a complementary paper to the paper \Coupling Eciency with Coupling Modes in ActiveDatabases, submitted to the VLDB96yAddress: Department of Computer Science, University of Toronto, 6 Kings College Road, Toronto,Canada M5S 3H5; Phone: (416) 978-7330; Fax: (416) 978-1455; e-mail: avigal@cs.toronto.edu1 a class in the object-oriented model, or a relation in the relational model. Derivedproperties are properties that their value is derived using rules. An external event is