Representing and Querying Semistructured Web Data Using Nested Tables with Structural Variants

This paper proposes an approach to representing and querying semistructured Web data. The proposed approach is based on nested tables, which may have internal nested structural variations to accommodate semistructured data. Our motivation is to reduce the complexity found in typical query languages for semistructured data and to provide users with an alternative for quickly querying data obtained from multiple-record Web pages. We show the feasibility of our proposal by developing a prototype for a graphical query interface called QSByE (Querying Semistructured data By Example). For QSByE, we define a particular variation of nested tables and propose a set of QBE-like operations that extends typical nested-relational-algebra operations to handle semistructured data. We show examples of how users can pose interesting queries using QSByE.