Abstract. We study containment of conjunctive queries that are evaluated over databases that may contain tuples with null values. We assume the semantics of SQL for single block qu...
Correctly generating a structured query (e.g., an XQuery or a SQL query) requires the user to have a full understanding of the database schema, which can be a daunting task. Alter...
The need to search for complex and recurring patterns in database sequences is shared by many applications. In this paper, we discuss how to express and support efficiently sophis...
Reza Sadri, Carlo Zaniolo, Amir M. Zarkesh, Jafar ...
A growing number of databases especially those published on the Web are becoming available to external users. Users of these databases are provided simple form-based query interfa...
We present here a formal foundation for an iterative and incremental approach to constructing and evaluating preference queries. Our main focus is query modification: a query tran...