Issue No. 06 - November/December (2003 vol. 15)
<p><b>Abstract</b>—In this paper, we study constraint databases with variable independence conditions (vics). Such databases occur naturally in the context of temporal and spatiotemporal database applications. Using computational geometry techniques, we show that variable independence is decidable for linear constraint databases. We also present a set of rules for inferring vics in relational algebra expressions. Using vics, we define a subset of relational algebra that is closed under restricted aggregation.</p>
Constraint databases, aggregation, closure, integrity constraints, spatiotemporal databases.
D. Toman, D. Goldin, G. Kuper and J. Chomicki, "Variable Independence in Constraint Databases," in IEEE Transactions on Knowledge & Data Engineering, vol. 15, no. , pp. 1422-1436, 2003.