Abstract data types in databases: Specification, manipulation and access

The basic data types from which records can be constructed in most database management systems are limited to a few simple types such as integers, reals, and character strings. There are many applications, exemplified by office automation, computer-aided design and geographic information systems, that could benefit from management of databases containing the complex objects typically used in programming these systems. We call databases that contain user defined abstract data types object-extended databases. In this paper we examine three aspects of providing support for object-extended databases: their specification, their manipulation by transactions, and access to them via queries. We show that a database specification scheme grounded formally in three abstract data types, finite sets, tuples and lists, accommodates the integration of databases and arbitrary abstract data types from the points of view of database designers, transaction programmers, and query writers and implemented.¹