Imposing disjunctive constraints on inter-document structure

Most of the contemporary web query systems has limited capabilities in imposing disjunctive constraints on the hyperlinked structure of Web documents. Such query facility is important because it gives us an opportunity to overcome the irregular and semistructured nature of the inter-document structure in the Web. In this paper, we describe a query mechanism called coupling query to address this issue in the context of our web warehousing system called WHOWEDA (Warehouse Of Web Data). We describe the syntax and semantics of the connectivities in a coupling query which enables us to impose disjunctive constraints on the inter-document structure. We describe two flavours of coupling query, i.e., canonical and non-canonical, and show how a non-canonical query can be transformed to a valid canonical query. Such transformation is useful for query evaluation.