A Hierchical Design Methodology
BibTeX
@MISC{Base_ahierchical,
author = {For Data Base and Jerry Baker and Raymond T. Yeh},
title = {A Hierchical Design Methodology},
year = {}
}
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Abstract
Concep..Represented by_System Moles The design of Level 4 includes four modules, each of which repre- sents an abstract concept visible to the system end-user. The RELATION module, for example, defines the operations by which users are able to create, modify, and view the primary data objects (relations) of this level. Likewise, the TUPLE module enables users to create and manipulate n-tuples as seperate entities. The AUTHORIZATION module relates to the concept of security in the data base system. Through the operations of this module it is possible to create authorizations which are assertions defining the allowable user accesses to the abstract data objects of Level 4. Certain operations also make it possible to scan all defined authorizations to determine if a user has access to a specified data object. The INTEGRITY module provides operations for defining and maintaining the semantic integrity of relations. For example, it is possible to create assertions which define allowable of these.
