Implementation of integrity constraints and views by query modification

TLDR

Relational database systems can decouple user interfaces from storage, enabling novel, powerful, and efficient integrity control schemes. The paper presents a mechanism to prevent integrity violations from improper updates and to support view usage in a relational system. The approach modifies each query at the language level to ensure no integrity violations, including support for virtual view definitions.

Abstract

Because the user interface in a relatonal data base management system may be decoupled from the storage representation of data, novel, powerful and efficient integrity control schemes are possible. This paper indicates the mechanism being implemented in one relational system to prevent integrity violations which can result from improper updates by a process. Basically each interaction with the data is immediately modified at the query language level to one guaranteed to have no integrity violations. Also, a similar modification technique is indicated to support the use of "views," i.e. relations which are not physically present in the data base but are defined in terms of ones that are.