2 cissp ® Official Study Guide Eighth Edition

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Chapter 20 
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Software Development Security
Database Management System Architecture
Although a variety of database management system (DBMS) architectures are available 
today, the vast majority of contemporary systems implement a technology known as rela-
tional database management systems (RDBMSs). For this reason, the following sections 
focus primarily on relational databases. However, first we’ll discuss two other important 
DBMS architectures: hierarchical and distributed.
Hierarchical and Distributed Databases
A hierarchical data model combines records and fields that are related in a logical tree 
structure. This results in a one-to-many data model, where each node may have zero, one, 
or many children but only one parent. An example of a hierarchical data model appears in 
Figure 20.7.
F I g u r e 2 0 . 7
Hierarchical data model
Chief Financial
Officer
Controller
Assistant
Controller
V.P., Tax
Chief Executive Officer
Chief Information
Officer
Network
Manager
Database
Manager
Chief Operating
Officer
Sales
Manager
Manufacturing
Manager
The hierarchical model in Figure 20.7 is a corporate organization chart. Notice that the 
one-to-many data model holds true in this example. Each employee has only one manager 
(the 
one
in 
one-to-many
), but each manager may have one or more (the 
many
) employees. 
Other examples of hierarchical data models include the NCAA March Madness bracket 
system and the hierarchical distribution of Domain Name System (DNS) records used on 
the internet. Hierarchical databases store data in this type of hierarchical fashion and are 
useful for specialized applications that fit the model. For example, biologists might use a 
hierarchical database to store data on specimens according to the kingdom/phylum/class/
order/family/genus/species hierarchical model used in that field.
The distributed data model has data stored in more than one database, but those data-
bases are logically connected. The user perceives the database as a single entity, even 
though it consists of numerous parts interconnected over a network. Each field can have 
numerous children as well as numerous parents. Thus, the data mapping relationship for 
distributed databases is many-to-many.

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Establishing Databases and Data Warehousing