Towards Relational Schema Uncertainty

摘要

In this paper we introduce the problem of managing uncertainty on the schema of a relational database. We formalize this problem using a possible world semantics, identify the challenges posed by the co-existence of many alternative schemata, and define some basic properties of a system with uncertain schemata. Finally, we describe a query rewriting system, i.e., the technique used to produce valid queries for each alternative schema, and study its properties.