This document provides an overview of database systems and Oracle database. It defines what a database is, the different types of databases, and why database design is important. It discusses data redundancy, data anomalies, and data normalization. It also describes the functions of a database management system (DBMS), advantages and disadvantages of DBMS, and the different editions of Oracle database.

1. Database
Administrator(Oracle)
Chapter 1: Database Systems
Presented by: Abdalle M. Geele
abdallegeele@gmail.com

2. Objectives
In this chapter, you will learn:
 The difference between data and information
 What a database is?
 What the various types of databases are, and
why they are valuable assets for decision
making
 The importance of database design
 Data redundancy and data inconsistency
 Data anomalies and types of anomalies
 The main functions of a database
management system (DBMS)
 Advantages and disadvantages of DBMS
 Oracle and its editions

3. Data Vs Information
 Data is stored representations of
objects and events that have meaning
and importance in the user’s
environment.
Structured
Unstructured
• Information is data that have been
processed in such a way as to
increase the knowledge of the person
who uses the data

4. What database is?
Database is an organized collection of
logically related data. So that it can
easily be manipulated, accessed and
managed.
Types of Databases
Databases can be classified according
to:
 Number of users
 Database location(s)
 Expected type and extent of use

5.  List the types of databases? Give an
example for each?

6. Types of Databases
 Single-user database supports only
one user at a time
– Desktop database – single-user, runs on PC
 Multiuser database supports
multiple users at the same time
– Workgroup database supports a small
number
– Enterprise database supports a large number

7. Types of Databases
 Centralized database: data located at
a single site
 Distributed database: data
distributed across several different
sites
 Operational database: supports a
company’s day-to-day operations
– Transactional or production database
 Data warehouse: stores data used for
tactical or strategic decisions

8. Why Database Design is
Important?
 Database design focuses on design of
database structure used for end-user
data
– Designer must identify database’s expected use
 Well-designed database:
– Facilitates data management
– Generates accurate and valuable information
 Poorly designed database:
– Causes difficult-to-trace errors

9. Discussion
 What is:
 Data Redundancy?
 Data Anomalies?
• What are the types of data anomalies?

10. Data Redundancy
 Data redundancy: same data stored
unnecessarily in different place.
 In simple words Redundancy means
repetition. In database terms,
redundancy refers to the fact that again
and again same data is repeated in a
table or database which occupies more
space.
 Modern databases are designed to
reduce redundancy. In certain cases,
redundancy cannot be eliminated 100%
but surely can be reduced.

11. Data Anomalies
 Data anomalies is abnormalities
when all changes in redundant data
not made correctly.
 Anomalies are problems that can
occur in poorly planned, un
normalised databases where all the
data is stored in one table.
 Updation anomaly
 Insertion anomaly
 Deletion anomaly

12. Insertion Anomaly
 The insertion anomaly is the inability
to add data to the database due to the
absence of other data.
 It occurs when certain attributes can
not be inserted into the database
without presence of other attributes.

13. Updation Anomaly
 An updation anomaly exists when
one or more instances of duplicated
data is updated, but not all.

14. Deletion Anomaly
 Deletion anomaly exists when certain
attributes are lost because of the
deletion of the other attributes.

15. Normalization
 Normalization is the process of
removing or minimizing redundancy
from a table.
Name Age Class Division
Ali 14 8 A
Ali 14 8 A

16. The Database System
Environment
Database system: defines and
regulates the collection, storage,
management, use of data • Five major
parts of a database system:
 Hardware
 Software
 People
 Procedures
 Data

17. The Database System
Environment (continued)
 Hardware: all the system’s physical devices
 Software: three types of software required:
Operating system software
 DBMS software
Application programs and utility software
 People: all users of the database system:
 System and database administrators
 Database designers
 Systems analysts and programmers
 End users
• Procedures: instructions and rules that govern the
design and use of the database system
• Data: the collection of facts stored in the database

18. Database Management
System
 Database management system
(DBMS) is a software system that is
used to create, maintain, and provide
controlled access to user databases.

19.  What are the advantages and
disadvantage of the DBMS?

20. Advantages of DBMS
1. Improved data sharing
An advantage of the database management approach is, the
DBMS helps to create an environment in which end users have
better access to more and better-managed data.
 Such access makes it possible for end users to respond
quickly to changes in their environment.
2. Improved data security
The more users access the data, the greater the risks of data
security breaches. Corporations invest considerable amounts of
time, effort, and money to ensure that corporate data are used
properly. A DBMS provides a framework for better enforcement
of data privacy and security policies.
3. Improved decision making
Better-managed data and improved data access make it
possible to generate better-quality information, on which better
decisions are based. The quality of the information generated
depends on the quality of the underlying data.
Data quality is a comprehensive approach to promoting the
accuracy, validity, and timeliness of the data. While the DBMS
does not guarantee data quality, it provides a framework to
facilitate data quality initiatives.

21. Disadvantages of Database
Management System (DBMS):
1. Increased costs
One of the disadvantages of dbms is Database systems require
sophisticated hardware and software and highly skilled personnel. The
cost of maintaining the hardware, software, and personnel required to
operate and manage a database system can be substantial. Training,
licensing, and regulation compliance costs are often overlooked when
database systems are implemented.
2. Management complexity
Database systems interface with many different technologies and have
a significant impact on a company’s resources and culture. The
changes introduced by the adoption of a database system must be
properly managed to ensure that they help advance the company’s
objectives. Given the fact that database systems hold crucial company
data that are accessed from multiple sources, security issues must be
assessed constantly.
3. Maintaining currency
 To maximize the efficiency of the database system, you must keep
your system current. Therefore, you must perform frequent updates
and apply the latest patches and security measures to all
components.
 Because database technology advances rapidly, personnel training
costs tend to be significant. Vendor dependence. Given the heavy
investment in technology and personnel training, companies might

22. What is Oracle?
 Oracle database is a relational
database management system. It is
known as oracle database, oracle DB
or simply oracle.
 It is produced and marketed by oracle
corporation.
 Oracle database is the first database
designed for enterprise computing.
Enterprise computing provides the
most flexible and cost effective way to
manage information and applications

23. Different editions of Oracle
database
 Following are the four editions of the
Oracle database
1.Enterprise edition: it is the most
secure edition. It offers all features
including performance and security
2.Standard edition: it provides the base
functionality for users that do not
require enterprise editions package.
3.Express edition(XE): it is lightweight,
free and limited windows and Linux
edition
4.Oracle lite: it is designed for mobile
devices.

24. The Beginning - 1977
 Larry Ellison co-founded Oracle
Corporation in 1977 with Bob Miner
and Ed Oates under the name
Software Development Laboratories
(SDL)
 Ellison took inspiration from the 1970
paper written by Edgar F. Codd on
relational database management
systems(RDBMS) named “A
Relational Model of Data for Large
Shared Data Banks.”

25. Oracle Corporation – 1979,
1982, 1995
 Ellison wanted to make Oracle’s product
compatible with the IBM system but
failed to do.
 SDL changed its name to Relational
Software Inc.(RSI) in 1979
 Then again changed to Oracle Systems
Corporation in 1982
 In 1995, Oracle Systems Corporation
changed its name to Oracle Corporation,
Officially named Oracle but sometimes
called to as Oracle Corporation.