Abstract
Uncertain data in databases were originally denoted as null values, which represent the meaning of `values unknown at present'. Grant generalized null values into partial values to provide a more powerful notion. An important operation-division, is fully studied to handle partial values. Due to the uncertainties of partial values, the extended divisions may produce maybe tuples. To process this extended division, the authors decompose a relation consisting of partial values into a set of relations containing only definite values by employing the concepts of interpretation. Bipartite graph matching techniques are then applied to develop efficient algorithms for the extended division that handles partial values. A refinement on the maybe result tuples of an extended division is also discussed