Querying Web Data: A Computational Perspective

Database and Artificial Intelligence Group hosting a talk by Andrea Cali

ABSTRACT

The Deep Web is constituted by data that are stored in databases and that can be accessed only dynamically, by requesting them e.g. through an HTML form. The problem of querying such Web data in relational form has been studied in the literature since the 1990s and several theoretical results have been since then established. In this talk we present a formalisation of the query answering problem as well as some results on the query answering and query containment problem. We then argue that in order to properly characterise the complexity of query answering a specific computational formalism is necessary; we present our formalism, illustrate its generality, and we present some results on the computational complexity of the basic problems under the aforementioned formalism.

Andrea Cali, University of London