�ݺ�ߣ

Institute of SouthernPunjab,
Multan
Mr. Saif ur Rehman Khan
BS (Computer Science)
MS (Data Science, and Computer Science)
Honors:
Certified Android Developer, Research Assistant
E-Mail: saifurrehman.khan@outlook.com

2
Database Systems
Lecture#1
Introduction to Database

Course- Objectives
 Introduce basic database concepts.
 Data Storage & retrieval techniques.
 Database Design.
 Different data models.
3

Course Primarily- Objectives
 Relational data model.
 Database Management System (DBMS) concepts.
4

Chapter 1 - Objectives
 Some common uses of database systems.
 Characteristics of file-based systems.
 Problems with file-based approach.
 Meaning of the term database.
 Meaning of the term Database Management System
(DBMS).
5

Chapter 1 - Objectives
 Typical functions of a DBMS.
 Major components of the DBMS environment.
 History of the development of DBMS.
 Advantages and disadvantages of DBMS.
6

Examples of Database Applications
 Purchases from the supermarket
 Purchases using your credit card
 Booking a holiday at the travel agents
 Using the local library
 Taking out insurance
 Renting a video
 Using the Internet
 Studying at university
7

History:
 Computers initially used for computational / engineering
process.
 After some time it has been thought that why should not used
computer for commercial application. So in this way some
languages were being used for such purpose like COBOL
language.
 Commercial application introduced File Processing System.
8

File-Based Systems
 Collection of application programs that perform services
for the end users (e.g. reports).
 Each program defines and manages its own data.
9

File-Based Systems
 Each system maintain data and processing its own.
 Each system has own data and program/application. Each
system store there own data separately and process
independently.
 Each system have own program for the purpose of processing
(Read / Store / Minor Calculation / output on the screen).
 In each system program and data are interdependence because
program and data are depended on one another.
10

Limitations of File-Based Approach
 Program-Data Dependence
 All programs maintain metadata for each file they use
 Duplication of Data
 Different systems/programs have separate copies of the same data
 Limited Data Sharing
 No centralized control of data
 Lengthy Development Times
 Programmers must design their own file formats
 Excessive Program Maintenance
 80% of information systems budget
12

Limitations of File-Based Approach
 Incompatible file formats
 Programs are written in different languages, and so cannot easily
access each other’s files.
 Fixed Queries of application programs
 Programs are written to satisfy particular functions.
 Any new requirement needs a new program.
13

Problems with Data Dependency
 Each application programmer must maintain his/her own data
 Each application program needs to include code for the meta
data of each file
 Each application program must have its own processing
routines for reading, inserting, updating, and deleting data
 Lack of coordination and central control
 Non-standard file formats
14

Problems with Data Dependency
 If data is being changed then the program must be changed and vice
versa For example if a library system has some attributes about book
like.
 Book_id
 Book_name
 Book_title
 Book_author
And after some time we add an other attribute like book_edition. So
you need to change data but on other hand you have to change the
program as well because program is dependent on data and vice
versa It means that if you change the data in library system you will
have to change Examination and Registration systems.
16

Figure 1-3 Old file processing systems at Pine Valley
Furniture Company
Duplicate Data
17

Problems with Data Redundancy
 Waste of space to have duplicate data
 Causes more maintenance issues
The biggest problem:
 Data changes in one file could cause inconsistencies
 Compromises in data integrity
18

No data sharing concept and inconsistency
 Attribute Address appears in two systems, Examination
and Registration. (Duplication)
 It creates inconsistency
 for example if a student changes his address in registration
system and not updated examination
 Address of student is different for registration information
communication and examination information communication.
20

SOLUTION:
The DATABASE Approach
21

Definitions
 Database:
 A database is a shared collection of logically related data,
which is stored to meet the requirement of different users of
an organization.
 Data: Raw facts about any thing.
 stored representations of meaningful objects and events
 Structured: numbers, text, dates
 Unstructured: images, video, documents
22

Definition1
 Logically related data: for example a man is working in a company
and we want to get facts/data about such worker. We can gather many
data like
 Necessary Data
 Name
 FName
 Address
 So many….
 Unnecessary Data
 Size of shoe
 Hair color
 Height
 Weight
 So many….
23

Definition1
 Shared Collection: There are some data that is common for different
systems. Such data must not be duplicated and that should be shared
25

Definition 2:
 A database is a self describing collection of integrated records.
 Self describing:
 In database, there are not only data stored but also
structure/definition/checks of that data. (In DBMS it is called
Schema/meta data. We will see later in more detail)
 Meta data is the part of database
26

Definition 2:
 Integrated record:
 Records are linked to one another
 When you see a record, to understand full meaning of that record
you will have to consider another record.
 It means that for understanding of a record you need another
record which is linked with it.
27

Definitions
 Information: data processed to increase knowledge of the person
using the data.
 The processed data is called information (adding some knowledge).
 Process means to add something to data.
 To name/ label data is also a process.
 Process can also add some knowledge, some information to the data.
28

Graphical displays turn data into useful
information that managers can use for
decision making and interpretation
Figure 1-1b Summarized data
30

Descriptions of the properties or characteristics of the
data, including data types, field sizes, allowable
values, and data context
31

 Data sharing (common data is being stored at one place rather than
storing the same on separate terminals)
 Data independence: Both data and program are now independent, if
you change data in one system, only that system will require the
change.
 Controlled Redundancy (Duplication)
 Better Data Integrity
 Data consistency
 Better data security
32

 Control of data redundancy
 Data & resource sharing eliminates or at least minimize
duplication
 Better concurrency control
 Multiple users access the data at the same time e.g. ATM
 Better Backup and Recovery procedure
33

Database Management System
DBMS manages data resources like an operating system manages hardware resources
 A software system that is used to create, maintain, and provide
controlled access to user databases
Order Filing
System
Invoicing
System
Payroll
System
DBMS
Central database
Contains employee,
order, inventory,
pricing, and
customer data
35

Database Management System
 (Database) application program:
a computer program that interacts with database by issuing an
appropriate request (SQL statement) to the DBMS.
36

Database Approach: Parts of DB
 Data Retrieval
 Data Manipulation Language (DML).
 Transaction Processing (TP)
 Data definition language (DDL).
 Data Control Language (DCL).
37

Views
 Allows each user to have his or her own view of the
database.
 A view is essentially some subset of the database.
38

Views - Benefits
 Reduce complexity
 Provide a level of security
 Provide a mechanism to customize the appearance of the
database
 Present a consistent, unchanging picture of the structure of
the database, even if the underlying database is changed
39

Components of DBMS Environment
40

 Hardware
 Can range from a PC to a network of computers.
 Software
 DBMS, operating system, network software (if necessary) and
also the application programs.
 Data
 Used by the organization and a description of this data called the
schema.
41

 Procedures
 Instructions and rules that should be applied to the
design and use of the database and DBMS.
 People
42

Roles in the Database Environment
 Data Administrator (DA)
 Database Administrator (DBA)
 Database Designers (Logical and Physical)
 Application Programmers
 End Users (naive and sophisticated)
43

History of Database Systems
 First-generation
 Hierarchical and Network
 Second generation
 Relational
 Third generation
 Object-Relational
 Object-Oriented
44

Advantages of DBMSs
 Control of data redundancy
 Data consistency
 More information from the same amount of data
 Sharing of data
 Improved data integrity
 Improved security
 Enforcement of standards
 Economy of scale
45

Advantages of DBMS
 Balance conflicting requirements
 Improved data accessibility and responsiveness
 Increased productivity
 Improved maintenance through data independence
 Increased concurrency
 Improved backup and recovery services
46

Disadvantages of DBMSs
 Complexity
 Size
 Cost of DBMS
 Additional hardware costs
 Cost of conversion
 Performance
 Higher impact of a failure
47

Summary of Lecture
 Some common uses of database systems.
 Characteristics of file-based systems.
 Problems with file-based approach.
 Meaning of the term database.
 Meaning of the term Database Management System
(DBMS).
48

Summary of Lecture
 Typical functions of a DBMS.
 Major components of the DBMS environment.
 History of the development of DBMS.
 Advantages and disadvantages of DBMS.
49

�ݺ�ߣ

Db lecture 1

Recommended

More Related Content

What's hot (20)

Similar to Db lecture 1 (20)

Recently uploaded (20)

Db lecture 1

Editor's Notes