Database Reference
In-Depth Information
12
Part
PartNum
Description
Warehouse
Price
OnHand
Class
AT94
Iron
Home Gym
50
45
32
21
8
12
22
12
8
9
HW
SG
AP
HW
AP
AP
HW
AP
AP
SG
3
2
1
3
2
3
3
1
3
2
$24.95
$794.95
$165.00
$129.95
$495.00
$399.99
$159.95
$349.95
$595.00
$1,390.00
BV06
CD52
DL71
DR93
Microwave Oven
Cordless Drill
Gas Range
DW11
Washer
FD21
KL62
KT03
KV29
Stand Mixer
Dryer
Dishwasher
Treadmill
FIGURE 1-12
Part report
ADVANTAGES OF DATABASE PROCESSING
The database approach to processing offers nine clear advantages over alternative data management methods.
These advantages are listed in Figure 1-13 and are discussed on the following pages.
1.
2.
Getting more information from the same amount of data
Sharing data
3.
4.
5.
Balancing conflicting requirements
Controlling redundancy
Facilitating consistency
6.
7.
Improving integrity
Expanding security
8.
9.
Increasing productivity
Providing data independence
FIGURE 1-13
Advantages of database processing
1. Getting more information from the same amount of data. The primary goal of a computer sys-
tem is to turn data (recorded facts) into information (the knowledge gained by processing those facts).
In a nondatabase, file-oriented environment, data often is partitioned into several disjointed systems,
with each system having its own collection of files. Any request for information that necessitates
accessing data from more than one of these collections can be extremely difficult to fulfill. In some
cases, for all practical purposes, it is impossible. Thus, the desired information is unavailable
it has
been stored in the computer, but it is scattered across multiple files. When all the data for the various
systems is stored in a single database, however, the information becomes available. Given the power
of a DBMS, the information is available, and the process of getting it is quick and easy.
2. Sharing data. The data of various users can be combined and shared among authorized users,
allowing all users access to a greater pool of data. Several users can have access to the same
piece of data
—
—
for example, a customer
'
s address
—
and still use it in a variety of ways. When one
user changes a customer
'
s address, the new address immediately becomes available to all users.
