Introduction to Data Management

1 An Overview of
Data Management
15873 Tandem Computers Incorporated 1-1
Most information processing systems involve the acquisition, storage, analysis, and
retrieval of data. When data processing people talk about the collective control of
these tasks, they often use the term data management.
On large and sophisticated computer systems, data management programs enable an
operator to query, augment, and manipulate large repositories of data. The functions
that create and access stored data, enforce data storage conventions, and regulate the
use of I/O devices, are all part of data management.
Online Transaction
Processing
On many computer systems, data management supports the processing of commercial
transactions in which goods or services are exchanged for money. Transaction
processing encompasses such diverse activities as credit verification, electronic
transfer of funds, hospital information retrieval, message switching, airline
operations, and many manufacturing and distribution functions.
Computer users often think of a transaction not as a real-world commercial
interaction, but as the computer operations that reflect that interaction. These
operations, including the entry of data about the interaction, the processing of that
data, and the resulting change in the stored collection of data, provide a computer
model of the real events that actually make up the transaction.
Computer users consider a transaction complete only when all computer operations
needed to process it against the stored data are finished, just as a salesperson and a
customer consider a transaction complete only when the customer has received and
paid for the item ordered.
Transaction processing today frequently takes place in an online processing
environment, with data stored on disk in a database. The database operates as one
large collection of information. With a database, users sitting at many terminals
located throughout a company can retrieve and update information immediately, as
shown in Figure 1-1.