The document discusses the distinctions between data and information, emphasizing how data becomes meaningful through processing and representation. It explores various record-keeping techniques, particularly contrasting manual systems with computerized database systems, highlighting the drawbacks of manual record systems like redundancy and inefficiency. It introduces database management systems (DBMS), which facilitate the management of large data collections, and categorizes different types of databases based on users, data location, and usage.

1. 1
Unit – 1
Introduction
Ayesha Asmat
Database Systems

2. 2
Data
• Data refers to the raw facts & figures concerning:
✓ PEOPLE
✓ EVENT
✓ ORGANISATION
✓ OBJECT
• The amount of available data in the modern computer world is
literally exploding.

3. 3
• Large volume of facts, difficult to interpret or make decisions based on
Data

4. 4
• Information is derived from data OR Information is the processed data
• Information may be presented either Textually or Graphically or both
• The representation and amount of information depends upon the
requirements of a user.
Data vs Information

5. 5
Record Keeping Techniques
1. Manual Record Keeping.
2. Computerized Record Keeping
a) File Processing System.
b) Database System (The paradigm shift)

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Manual System - Drawbacks
• High data volume
• Not reliable
• Inefficient
• Duplication of data
• Inconsistency
• The System can’t answer complex queries
involving multiple departments.

7. 7
• Consider a College System consisting of the
following offices:
– Admission Office
– Academics Office
– Exam Office
• Each Office is maintaining its own set of files for
its day to day operations.
• Some of the files used in the system are Student’s
File, Faculty File, Course File, Correspondence
File etc.
Case Study

8. 8
File Processing System
File – 1
App – 1
(operations + data descriptions)
File – 2
File – n
App – 2
(operations + data descriptions)
App – n
(operations + data descriptions)

9. 9
File Processing System
Duplicate
Data

10. 10
File Processing System
• File-based systems were an early attempt to computerize
the manual filing system.
• The manual files were replaced by computer files.
• A person responsible for developing and managing
computerized file processing system was called Data
Processing (DP) specialist.
• In the traditional file processing system, the existing
manual system is automated by focusing on the data
processing needs of the individual departments instead of
treating the organization as whole.
• Each application will have its own set of Private Files
designed to meet the needs of a particular department.

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Drawbacks of File System
1. Redundancy of Data
2. Inconsistent Data
3. Limited Data Sharing
4. Lack of provision for security
5. Limited recovery from failure

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• Database is a collection of information that
is organized so that it can be easily
accessed, managed and updated.
• Database is a shared collection of logically
related data, about entities and the
relationships among these entities.
Database

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Entities
● An entity is any object in the system that we
want to model and store information
● Each table is about an object, person or thing.
● Customer
● Patients
● Books
● Products
● Teachers
These are known
as entities

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Student Table (Example)

15. 15
Table Example

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➢ Databases play a critical role in almost all areas where
computers are used.
➢ Databases are everywhere …
• Student / Employee’s Information System
• Library System
• Hotel / Airline Reservation System
• Billing System
• Stock / Inventory System
• Payroll System
• Geographical Information Systems (GISs)
Examples of Database Applications

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Database System
Database
(Data + Data Descriptions)
App – 1 (Operations)
D
B
M
S
App – 2 (Operations)
App – n (Operations)
DBMS manages data resources
like an operating system manages
hardware resources

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Database Management System (DBMS)
● A Database Management System (DBMS) is a
software designed to assist in maintaining and
utilizing large collections of data.
● A DBMS uses various powerful functions to store
and retrieve data efficiently.
● Language used to interact with database is
SQL(structure query language)
• Examples
• Microsoft Access
• MySQL
• Microsoft SQL Server
• FoxPro

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DBMS vs. File management
system

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Users in a DBMS environment

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Types of Databases
• Databases can be categories on the basis of
the following criterions:
Criteria Types
1. Number of users • Single User Database
• Multi-user Database
2. Data location • Centralized Database
• Distributed Database
3. Data usage • Operational
• Analytical

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Types of Databases
• Categories are:
– Personal computer databases(Single User)
– Workgroup databases(Multi-user)
– Department databases (Multi-user)
Single user with
desktop computer
Mainframe computer
with thousands of users

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Types of Databases
Personal Computer Databases
• Support one user with a standalone PC
• E.g. a student’s own database or a sales person’s simple
database
Workgroup Databases
• Workgroup: relatively small group of people who
collaborate on same project/application.
• A workgroup DB supports the collaborative efforts of a
workgroup.
• Allows data sharing.
• Its model is shown on the next fig:

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Continued…
Workgroup DB on LAN
(Method of Data Sharing)
DB Server
Workgroup
DB
LAN

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Types of Databases
Department Databases
• Department: Functional unit within an organization
• Department DBs support function & activities of a
department.
• E.g. personnel DB to track employees, jobs, skills etc.
Enterprise Databases
• DB scope is the entire organization
• To support organization-wide operations & decision
making.

27. 27
Continued…
Corporate
Office
Hospital
Medical
Clinic
Hospital
Nursing
Home
Medical
Clinic
Data
Warehouse

28. 28
Types of Databases
Centralized & Distributed Databases
• Centralized database system – supports a database located at a
single site
• Distributed database system – supports a database distributed
across several different sites