Database Reference
In-Depth Information
F
APPENDIX
DETERMINING INFORMATION-LEVEL
REQUIREMENTS
INTRODUCTION
In Chapter 6, you learned a method for creating information-level database designs, in which the starting point for the
design process is a set of user views. Each user view is the set of requirements that is necessary to support the operations
of a particular database user. In this appendix, you
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learn how to determine the specific user views, or information-level
requirements, required for a particular database.
INFORMATION SYSTEMS
A database is one of the components of an information system. As illustrated in Figure F-1, an information
system is the collection of data, people, procedures, stored data, software, hardware, and information
required to support a specific set of related functions. Examples of information systems are cell phone billing,
payroll, airline reservation, point of sale, pharmacy management, property tax assessment, online bridal
registry, and insurance premium processing. The Premiere Products, Henry Books, and Alexamara Marina
Group cases are also examples of information systems, although this topic has chiefly focused on the database
components of these information systems.
People
Procedures
Stored Data
Software
Hardware
Information
Data
Input
Processing
Output
FIGURE F-1
Information system components
As described in Chapter 1, the primary goal of an information system is to turn data (recorded facts) into
information (the knowledge gained by processing those facts). Data is input to an information system, and
the information system outputs information. Data can be input to an information system manually using, for
example, keyboards, telephones, or mobile devices, or by automated means using, for example, ATMs,
point-of-sale scanners, credit/debit card readers, and external files and databases. Information can be output
from an information system as printed reports, screen displays, external files and databases, or can be output
to specialized devices/media such as wireless, audio, and fax.
An information system is a success only when the people interacting with it and obtaining information
from it view it to be successful. The people component of an information system includes the end users
(those directly interacting with the information system), management, auditing and other support staff
groups, and often people in outside entities such as government agencies, suppliers, and financial institutions.
The people component also includes technical staff, who develop and maintain the information system and
who support the operating environment for the information system.
A procedure is a series of steps followed in a regular, specified order to accomplish one end result.
Examples of procedures in information systems are signing up a new cell phone customer, auditing a payroll
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