Unions of conjunctive queries, also known as select-project-join-union queries, are the most frequently asked queries in relational database systems. These queries are definable b...
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema. Given a source instance, there may be many solutions ? ta...
The problem of deciding query containment has important applications in classical query optimization and heterogeneous database systems. Query containment is undecidable for unres...
d abstract) Michael Benedikt Bell Labs Jan Van den Bussche Limburgs Universitair Centrum Christof L?oding Lehrstuhl Informatik VII RWTH Aachen Thomas Wilke Institut f?ur Informatik...
Computing frequent itemsets and maximally frequent itemsets in a database are classic problems in data mining. The resource requirements of all extant algorithms for both problems...
Ganesh Ramesh, William Maniatty, Mohammed Javeed Z...
A query against a database behind a site like Napster may search, e.g., for all users who have downloaded more jazz titles than pop music titles. In order to express such queries,...
Our work is motivated by the problem of managing data on storage devices, typically a set of disks. Such high demand storage servers are used as web servers, or multimedia servers...
Full disjunctions are an associative extension of the outerjoin operator to an arbitrary number of relations. Their main advantage is the ability to maximally combine data from di...