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This paper presents an application of a DL reasoner to the optimization of an object-relational query language. Queries containing aggregate functions are difficult to optimize be...
We argue for a new aggregate function we termed the LIST function. It aggregates a set of values of one or more attributes into a single value that is internally a list of these v...
is at least ae powerful as SQL. Two well known relational query languages that have a sound theoretical foundation are relational algebra and relational calculus. As SQL is more cl...
Abstract. In this paper we present a new approach for studying aggregations in the context of database query languages. Starting from a broad de nition of aggregate function, we ad...
A top-k query combines different rankings of the same set of objects and returns the k objects with the highest combined score according to an aggregate function. We bring to ligh...
Nikos Mamoulis, Kit Hung Cheng, Man Lung Yiu, Davi...