1. CSCS 213
DATABASE SYSTEMS

2. System ?

3. System is a collection of integrated parts which work together to achieve some objective? ? ? ?

4. System System Working together Objective
Collection of integrated parts
Working together
Objective

5. System
INTEGRATED PARTS ?

6. INTEGRATED PARTS
System
Parts
necessary for the survival of each other

7. ? EXAMPLE INTEGRATED PARTS System Parts
necessary for the survival of each other ?
EXAMPLE

8. System
WHY WORK TOGETHER ?

9. If they do not, system will CRASH.
WHY WORK TOGETHER
If they do not, system will CRASH.

10. ?
EXAMPLE

11. ?
EXAMPLE
POLICE system

12. ?
ANY OTHER EXAMPLE

13. The desired destination
OHBJECTIVE ?
The desired destination

14. Database

15. Database
Data

16. 1
Data
Material
General
Raw
Unordered
Unorganized
Meaningless

17. Collection of facts and figures2
Data
Raw Material
Mostly used
Collection of facts and figures

18. Any thing that is acceptable
Data
Fact
Any thing that is acceptable

19. Data
Examples: Facts
Education:
MBA
Aslam
Color:
Red
Green 20

20. Any thing that is countable
Data
Figure
Any thing that is countable

21. Data
Examples: Figures
Age(Yrs): 25
Salary(Rs):
50,000/-

22. Artificial Intelligence
Data
Example
Class Roster Course: CS Semester: Fall Developments in IT Section: A
Name ID
Major
GPA
Asad
993124
Databases
3.5
Aslam
992134
Data Communications
3.4
Waheed
992314
Software Engg.
3.2
Babur
992112
Kaleem
991111
Artificial Intelligence

23. Data Summary Raw Material with no useful meaning Unorganized Material
Collection of facts and (or) figures
Material to be processed
Telephone Conversation: Electrical signals in wires
Word processor letter: stored on floppy disk
123, A+, 71, Aslam, 20/4/2000.

24. DATA
Why do we need data?

25. Data is the key to success for organizations to run businesses.
Required for the survival of the organizations
Required for competitive initiatives:
Improving customer satisfaction
Facilitating teamwork
Developing new products & markets
Providing faster response
Assuring quality
…….

26. Data must be secured and protected from destruction and misuse.
Limitations
Data can be an asset only if:
It is accurate
It is available when needed
Organization must store, organize & manage its data
Data must be secured and protected from destruction and misuse.

27. DATA Limitations No redundant data No inconsistent data
One copy of each data item
Almost no duplication
No inconsistent data
No contradiction of data
Inconsistent Performance by Pakistan Cricket Team
Age
Age 25 25
Saeed =145
Saeed =03

28. DATA
Limitations
Less maintenance
Shared access to data

29. Data
Types of
Data
Numeric
Non-Numeric

30. Data 234 2.64 Integer Float Numeric Data Digits
Numbers
Integer
Float
0, 1, 2, 3, 4, ……, 8, 9
234
2.64

31. Data
Non-Numeric
Data
Alphabetic
Data
Alpha-Numeric
Data

32. Characters (Alphabets)
Data
Alphabetic
Data
Characters (Alphabets)
Strings
a, b, c, d, ……, y, z
Aslam, BS(CS)

33. Data Combination of Alphabetic and Numeric data
Alpha-Numeric
Data
Combination of Alphabetic and Numeric data
23-E-III, Gulberg-III, Lahore.

34. Data ?
Information

35. Information Items of knowledge Anything having meaning to people
Organized material
Processed data
A list of names, addresses etc.
Contents of a letter
Telephone Conversation
Words of a song
A map, graph

36. Information
Information is used for performance measurement and decision making.
Data and Information are conceptual resources of an organization.

37. Information Example

38. Information Example

39. Comparision of Cricket Scores on screen
Information Example
Comparision of Cricket Scores on screen

40. DATA PROCESSING CYCLE Sequence of operations for
data collection, input, process, output

41. DATA PROCESSING CYCLE Data collection Input (Select) Process(Action)
Output(Result)
Data collection
Output
Input
Process

42. DATA PROCESSING TYPES Manual Data Processing
Electronic Data Processing

43. Manual Data Processing (Manual Information System)
Customer file
Order file
Sales Dept.
Sales order
Orders Dept.
Accounting Dept.
Product file
Work order
Work order file
Packing
slip
Customer
Invoice
Invoice File
Manufacturing & Store

44. Manual Data Processing (Manual Information System)
All record keeping done with the help of registers.
Communication manually (or telephonically).
Each department having its own record system to support its operations.
Data files are decentralized. Each department works with a subset of the organization’s data.

45. Manual Data Processing (Manual Information System)
Drawbacks
A constant stream of intra-company paperwork (memos, reports etc.) and telephone calls is required to communicate changes and keep the files synchronized.
No answers to complex operational questions.
Summary information required for decision making is not easily available to the managers.
Data redundancy and inconsistency.

46. Typical User Questions
Department
File
Typical Question
Sales
Customer
What is customer XYZ’s address and credit limit?
Orders
Product
How many chairs (product no. 157) do we have in stock?
Accounting
Invoice
How much customer XYZ owe us on invoice no. 253?
Sample Complex Question:
How many units of product 123 were sold on 26/04/2001 and at what rate?

47. Electronic Data Processing
Computer is involved

48. Computer
HARDWARE
SOFTWARE

49. All the physical components
HARDWARE
All the physical components

50. All the programs and data
SOFTWARE
All the programs and data

51. PROGRAM
A set of instructions

52. Electronic Data Processing
File Processing System
Database System

53. FILE
PROCESSING SYSTEM

54. File Processing Systems
A traditional approach
Each department having its own data processing system.
A separate program to meet the user requests.

55. File Processing Systems
Drawbacks
Data redundancy
Duplication of data in different files
Data inconsistency
Difficulty in accessing data
Data isolation — multiple files
Limited Data Sharing
No concurrent access by multiple users
Inflexibility
Security problems
Excessive maintenance
Database systems offer solutions to all the above problems

56. DATABASE SYSTEM

57. Database ?
Collection of Tables(files)

58. Database ?
Table
Collection of records

59. Database Table Name ID Major GPA Asad 993124 Marketing 3.5 Aslam
992134
Finance
3.4
Waheed
992314
Management
3.2
Babur
992112 IT
Kaleem
991111
Saleem
992104
3.1
Record
Example

60. Database
What is a record?
Where do we collect records?

61. Database
Record
Collection of field values

62. Database
Field
An attribute of an entity

63. Database
Attribute
Property of an entity

64. Any thing about which data is stored.
Database
Entity
Any thing about which data is stored.

65. Database
Entity
Examples:
Specific person, company, event

66. Database Entity Example:
An entity is represented by a set of attributes.
Example:
customer = (cust-id, name, street-no, city)

67. Attributes Example STUDENT Attributes Entity STUDENT NO NAME ADDRESS
PHONE NO
STUDENT
Attributes
Entity

68. Attribute Example Attributes EMPLOYEE:
EMPLOYEE NO, NAME, ADDRESS, SKILL
Attributes

69. Attribute Types Simple and composite attributes.
Single-valued and multi-valued attributes
Derived attributes
Can be computed from other attributes
E.g. age, from date of birth

70. Derived E.g. age, from date of birth
Attribute Types
Examples
Simple
Composite
Single-valued
Multi-valued
Derived E.g. age, from date of birth
GPA=3.5

71. Composite and Component Attributes
Name
Composite Attribute
First Name
Middle Name
Last Name
Component Attributes

72. Domain The set (range) of permitted values for each attribute
Attribute does not accept value out of the given domain.
The special value null is a member of every domain.

73. Domain for Grade attribute here is
Example Domain
Roll No
Grade 1 A 2 B 3 F 4 C
Domain for Grade attribute here is
{ A, B, C, D, F }

74. ENTITY Examples Person: Place: Event: Concept:
Employee, Student, Patient
Place:
State, Region, Country
Event:
Sale, Registration, Renewal
Concept:
Account, Course, Work Center

75. Database
Value
Data

76. Database
Summary
Value
Field
Record
Table
Database

77. Database Summary Value Field Field Field Record Record Table Table
Name ID
Major
GPA
Asad
993124
Marketing
3.5
Aslam
992134
Finance
3.4
Waheed
992314
Management
3.2
Record
Record
Table
Table
Database

78. Database Data is generally unorganized
Database provides a way to store data in an organized way

79. Database
How
to organize data ?

80. By categorizing, data is organized
Database
By categorizing, data is organized

81. Data Non-categorized
123, Aslam, 71, A+, Lahore

82. Data is categorized into tables.
Data Categorized ID
Name
Marks
Grade
City
123
Aslam 71 A+
Lahore
Data is categorized into tables.

83. A place where data is stored.
Database
Collection of organized data.
A database consists of multiple tables.
A place where data is stored.

84. Database Applications
Banking:
All transactions
Airlines:
Reservations Schedules
Universities:
Registration Grades
Sales:
Customers Products Purchases
Manufacturing:
Production Inventory Orders Supply chain
Human resources:
Employee records Salaries Tax deductions
Databases touch all aspects of our lives

85. Database System Computerized record keeping system,
to maintain information and to make
information available on demand.

86. Database Systems =
Computerized Record-keeping System

87. Shared corporate database
Marketing
Management
Corporate
Database
Materials
Accounting
Manufacturing

88. Types of Databases
Centralized Databases
Distributed Databases

89. Centralized Databases
All the data are located at a single site.
Users at remote sites access the database using data communication facilities.
Provides greater control over accessing and updating data than distributed databases.
More chances to failure since the availability of the resources at the central site.
Applications:
Airline Reservation Systems
Financial Institutions
ISP’s

90. Centralized Databases
Central Computer

91. Centralized Databases
Client:
A software application that requests the services from one or more servers.
Server: (The server is the DBMS itself)
A software application that provides the services to requesting clients.
Database processing is performed on the database server

92. Distributed Databases
Multi-national organizations
Geographically dispersed
A distributed database is a single logical database that is spread physically across computers in multiple locations connected by a data communication network.
A user requesting data need not know the location of the data.
Any request to retrieve or update data at a non-local site is automatically forwarded by the system to the requested site.
The user is unaware of the distribution of data, and all data in the network appear as a single logical database.

93. Distributed Database Architecture
Location B
Location A
Database
Database
Computer
Computer
Database
Computer
Location C

94. Database Management System
A software system that is used to create, maintain and provide controlled access to user databases.
DBMS provides an environment that is both convenient and efficient to use.

95. Architecture of Database System
DBMS
Users
Application
Programs
Database
DBA Users
Client
Database Server

96. Data to Information Lahore $150 Aslam xyz 5% INVOICE DATABASE DBMS
Processing
INVOICE
Name: Aslam City: Lahore Date: Nov. 15, 2003
Books $15
Others $20
Discount $5 Total $30
Information

97. Keys in DBMS
Every entity must have an attribute that uniquely identifies each record and clearly distinguishes that record from other records of the same entity.
Key
An attribute used to identify a record uniquely is called key.

98. Types of Keys in DBMS Candidate Key
All columns capable to become the Key.
Some entities may have more than one candidate key.

99. Example Two candidate keys
RNo
RegNo
Name
PhNo
992132
1245
Smith
991231
1456
Miller
991253
1324
Scott
991251
1233
King

100. Types of Keys in DBMS Primary Key
If there are more than one candidate keys, the designer must choose one of the candidate keys as the identifier for the entity. This selected candidate key is called primary key.
It always contains unique values for each record.
It is not NULL at all.
Only one Primary Key in a table.

101. Types of Keys in DBMS Alternative Key
Out of candidate keys, one attribute would be selected for the primary key, remaining candidates keys will become alternative keys.
Alternative keys are alternatives to primary key.

102. Primary key STUDENT Primary key STUDENT NO NAME ADDRESS
PHONE NO
STUDENT
Primary key

103. Example Two candidate keys
Primary Key
Alternate Key
RNo
RegNo
Name
PhNo
992132
1245
Smith
991231
1456
Miller
991253
1324
Scott
991251
1233
King