A Formal System for Reasoning about Programs Accessing a Relational Database

A formal system for proving properties of programs accessing a database is introduced. Proving that a program preserves consistency of the database is one of the possible applications of the system. The formal system is a variant of dynamic logic and incorporates a data definition language (DDL) for describing relational databases and a data manipulation language (DML) whose programs access data in a database. The DDL is a many-sorted first-order language that accounts for data aggregations. The DML features a many-sorted assignment i place of the usual data manipulation statements, in addition to the normal programming language constructs