Aggregation Queries of Uncertain Data in Relational Databases

Although database technologies employ integrity constraints to maintain certainty of data, and some situation may be satisfied with integrity constraints. This paper proposes uncertain databases and candidate databases. To uncertainty of tuple values in uncertain databases and their aggregation queries with different results for every candidate database, the work adjusts query semantics to employ query writing for computing the maximum and the minimum of aggregation attributes based on certain range semantics, the method can execute effectively SQL query in databases.