A normal form for abstract syntax

• Authors: John Miles Smith
• Venue: VLDB '78 Proceedings of the fourth international conference on Very Large Data Bases - Volume 4
• Year: 1978

McCarthy's abstract syntax is the most widely used metalanguage for specifying data structure. It is embedded in various forms in most recent programing languages and data models. A simpler, yet more powerful, abstract syntax is defined which is particularly effective in database applications. An abstract syntax specification shows how objects are composed as the union and cartesian product of other objects. If a specification is not properly constructed, it is demonstrably difficult to write application programs, maintain database integrity and provide graceful evolution. A normal form, called (3,3)NF, for abstract syntax specifications is introduced. Specifications in this normal form are subject to far fewer of the above utilization problems. Unlike previous normal forms which only prescribe composition with respect to cartesian product, (3,3)NF also prescribes composition with respect to union. Examples of normalization are given and the advantages and limitations of the approach are discussed.