OVERVIEW OF ADMINISTRATION FUNCTIONS - Database Design and Development: An Essential Guide for IT Professionals - page 420

back up the data content, to safeguard the data from concurrent updates, and so on.
Now, with the Internet, data warehousing, and analytical processing, the scope and
usage of database systems have expanded tremendously.
How can organizations make use of the remarkable power and range of today's
DBMSs? Only by having a group or an individual fully trained in particular DBMSs.
The DBA in an organization must have expertise in the particular commercial
DBMS that manages its database system.
Data Integrity A database is only as good as the integrity and correctness of the
data it contains. If the data are incorrect or inconsistent, then the worth of the data-
base is greatly diminished. For example, if the database in a large medical center
shows the room numbers of the inpatients and if you do not find the patients in the
room numbers shown by the database system, then the database is worthless as far
as patient locations are concerned.
Data integrity in a database may be compromised in a number of ways. If proper
edits are not instituted, incorrect data creep in. In a relational database, if entity
integrity and referential integrity are not enforced, data may get out of line. When
concurrent transactions attempt to update the same data elements simultaneously,
without proper concurrency controls, the data elements may be left with incorrect
values.
The administration role in a database environment has the serious responsibility
of preserving data integrity. The administrator must accomplish this through proper
edits, constraints, and concurrency controls. He or she needs special training and
knowledge in data integrity methods.
Data Availability Modern enterprises depend on the information contained in
their operational databases to run their day-to-day businesses. Profitability, com-
petitive edge, and even the very survival of many businesses rest heavily on the
strength of their database systems. Organizations need their database systems to be
up and available all the time. 24/7 operation is especially critical for global organi-
zations with user locations spread out worldwide.
Can you imagine an airline reservation system down even for a few minutes?
What about the databases in banks and financial institutions? Can these be down
for even short durations? Think of the databases supporting defense applications
and government departments. Continuous availability of the corporate database
is a critical requirement. Apart from scheduled downtime for maintenance, an
organization's database must always be available to users in today's business
environment.
What can go wrong, and why would database systems become unavailable? Many
types of hardware and software malfunctions can interrupt availability. The organi-
zation has to recover quickly from such disruptions and make the database acces-
sible again. We will consider database recovery in greater detail in Chapter 15. Right
now, realize that recognizing malfunctions and taking suitable actions to recover the
database are intricate functions. An organization needs specially trained profes-
sionals to perform such complicated functions.
Resource Management Many types of hardware and software resources work
together to make the database system of an organization functional. You need