Towards efficient metaquerying

Metaquery (also known as metapattem) is a datamining tool useful for learning rules involving more than one relation in the database. A metaquery is a template, or a second-order proposition in a language L, that describes the type of pattern to be discovered. This tool has already been successfully applied to several real-world applications. In this paper we advance the state of the art in metaqueries research in several ways. First, we analyze the related computational problem and classify it as NP-hard, with a tractable subset that is quite immediately evident. Second, we argue that the notion of support for metaqueries, where support is intuitively some indication to the relevance of the rules to be discovered, is not adequately defined in the literature, and propose our own definition. Third, we propose some efficient algorithms for computing support and present preliminary experimental results that indicate that our algorithms are indeed quite useful.