Numerical Operations on a Relational Database

This paper addresses the problem of defining numerical operations on a relational database to accommodate the statistical analyses associated with a bivariate frequency table. An attempt has been made to extend Codd's relational algebra to include simple bivariate statistical operations preserving the closure of Codd's algebra. This extended algebra is applied to bivariate relational data structures needed for Realtime automatic statistical quality control of a manufacturing process. We also discuss some new category-numeric operations on relational tables. © 1989 IEEE