In this paper, we present the concept of relational patterns and our approa
ch to extract them from multiple relational tables. Relational patterns are
analogous to frequent itemsets extracted by the Apriori algorithm [R, Agra
wal, H. Mannila, R. Srikant, H. Toivonen, A.I. Verkamo, Advances in Knowled
ge Discovery and Data Mining, AAAI Press, 1995.] in the case of a single ta
ble. However, for the multiple relational tables, relational patterns captu
re co-occurrences of attributes as well as the relationships between these
attributes, which are essential to avoid information loss. We describe our
experiences from a test-bed implementation of our approach on a real hospit
al's discharge abstract database. This process raised issues, which were th
en implemented in order to enhance an analyst's ability to explore patterns
while preventing high diversity and abundance of available data from blurr
ing subtle patterns of interest. Finally, we evaluate the usefulness of rel
ational patterns in the context of the discharge abstract data as well in o
ther possible domains. (C) 1999 Elsevier Science B.V. All rights reserved.