Formulating disjunctive coupling queries in a web warehouse

We describe how to formulate a coupling query to glean relevant Web data in the context of our web warehousing system called WHOWEDA (Warehouse Of Web Data). Coupling query may be used for querying both HTML and XML documents. One of the important feature of our query mechanism is the ability to express conjunctive as well as disjunctive query conditions compactly. We describe how to formulate a coupling query in text form as well as pictorially using the coupling text and the coupling graph respectively. We explore the limitations of coupling graph with respect to the coupling text. We found out that AND-, OR- and AND/OR-coupling graphs are less expressive than their textual counterparts. To address this shortcoming we introduce the notion of hybrid graph which is a special type of p-connected coupling graph. Finally, we discuss the implementation of a GUI-based system called VISCOUS (VISual COupling QUery System) for formulating such queries. (C) 2002 Elsevier Science B.V. All rights reserved.