Information Technology Reference
In-Depth Information
Locating a particular record that meets a specific set of criteria might be easier and faster
using a combination of secondary keys. For example, a customer might call a mail-order
company to place an order for clothes. If the customer does not know the correct primary
key (such as a customer number), a secondary key (such as last name) can be used. In this
case, the order clerk enters the last name, such as Adams. If several customers have a last name
of Adams, the clerk can check other fields, such as address, first name, and so on, to find the
correct customer record. After locating the correct customer record, the order can be com-
pleted and the clothing items shipped to the customer.
The Database Approach
At one time, applications used specific files. For example, a payroll application would use a
payroll file. In other words, each application used files dedicated to that application. This
approach to data management, whereby separate data files are created and stored for each
application program, is called the
traditional approach to data management
.
Today, most organizations use the
database approach to data management
, where mul-
tiple application programs share a pool of related data. A database offers the ability to share
data and information resources. Federal databases, for example, often include the results of
DNA tests as an attribute for convicted criminals. The information can be shared with law
enforcement officials around the country.
To use the database approach to data management, additional software—a database
management system (DBMS)—is required. As previously discussed, a DBMS consists of a
group of programs that can be used as an interface between a database and the user of the
database and application programs. Typically, this software acts as a buffer between the
application programs and the database itself. Figure 5.3 illustrates the database approach.
traditional approach to data
management
An approach whereby separate data
files are created and stored for each
application program.
database approach to data
management
An approach whereby a pool of
related data is shared by multiple
application programs.
Figure 5.3
Payroll
program
Reports
The Database Approach to Data
Management
Payroll
data
Invoicing
program
Reports
Inventory
data
Database
management
system
Invoicing
data
Inventory
control
program
Reports
Other
data
Management
inquiries
Reports
Database
Interface
Application
programs
Users
Table 5.1 lists some of the primary advantages of the database approach, and Table 5.2
lists some disadvantages.
