1. ITS232 Introduction To Database Management Systems
CHAPTER 1
Database Concepts
Siti Nurbaya Ismail
Faculty of Computer Science & Mathematics,
Universiti Teknologi MARA (UiTM), Kedah
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2. Chapter 1: Database Concepts
1.1 Introducing The Database
1.2 The Historical Roots Of Database
1.3 Files And File Systems
1.4 A File System Critique
1.5 Database Systems
1.6 Database Models

3. 1.1 Introducing The Database 1.1.1 Data and information
Raw facts
Building blocks of information
Examples:
Norasyikin Mohd Noor
CS110

4. 1.1 Introducing The Database 1.1.1 Data and information
Produce by processing data
Reveal meaning of data
Examples:
is Norasyikin Mohd Noor
UiTM Metrics Number and currently she is in semester 4, studying in CS110 Program at UiTM Merbok, Kedah.

5. 1.1 Introducing The Database 1.1.1 Data and information
How do data and information relate?

6. 1.1 Introducing The Database A Glance of Database Concept
subject
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ITS232
Database
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Literature
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ITS232
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Hasmurni
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7. 1.1 Introducing The Database 1.1.2 What is database?
A shared collection of integrated computer structure designed to meet various needs of an organization.
It houses:
End-user-data : raw facts
Metadata : data about data
DBMS
DataBase Management System
A software that enable user to define, create, maintain and control access to database
Possible to share data among multiple applications or users
Makes data management more efficient and effective
Examples:
IBM DB2, MS Access, MySQL, ORACLE

8. 1.1 Introducing The Database 1.1.2 What is database?
DBMS
allows
Create Database
Create Forms
Create Reports
Sort Data
Retrieve Data

9. 1.1 Introducing The Database 1.1.2 What is database?
The importance of database:
Manage interactions between end users and database
Helps make data management more efficient and effective
Its query languages allows make quick answers to add-hoc queries
Provide end users better access to more and better managed data
Promote and integrated view of org’ operations big picture

10. 1.1 Introducing The Database 1.1.2 What is database?
Advantages of database:
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
improved data accessibility and responsiveness
increased productivity
improved maintenance through data independence
improved backup and recovery services

11. 1.1 Introducing The Database 1.1.2 What is database?
Disadvantages of database:
complexity
size (space)
cost of DBMS
additional hardware cost
cost of conversion
performance
higher impact of failure

12. 1.1 Introducing The Database 1.1.3 Types of database
Database can be classifieds into three types, they are:
Classified by number of user
Classified by used
Classified by locations

13. 1.1 Introducing The Database 1.1.3 Types of database
Types 1: Classified by number of user
Classified by number of user
Single-user
Supports only one user at a time
Desktop
Single user database, running on a personal computer
Multi-user
Supports multiple user at one time
Workgroup
supports a small group of user on a single department
Enterprise
supports a large group of users on entire organization

14. 1.1 Introducing The Database 1.1.3 Types of database
Types 2: Classified by used
Classified by used
Transactional / Production
Support immediate responses transaction
Company day-to-day transaction
Data warehouse
Stores data used to generate information required to make tactical or strategic decisions
Often used to store historical data
Provided by decisions support system (DSS), data massaging (data manipulation) to extract information from historical data
Data warehouse describe dB design by DSS

15. 1.1 Introducing The Database 1.1.3 Types of database
Types 3: Classified by locations
Classified by locations
Centralized dB
DBMS that supports a database located at a single site
Distributed dB
DBMS that supports a database distributed across several different sites

16. 1. 1 Introducing The Database 1. 1
1.1 Introducing The Database Why db are valuable assets for decision making?
Basically, database stored data, process data into information as needed by end-user (company)
Accurate, relevant, and timely information is key to good decision making
Good decision making is the key to survival in a global environment

17. 1.1 Introducing The Database 1.1.5 The importance of database design
Defines the database’s expected use
Different approach needed for different types of databases
Avoid redundant data
Poorly designed database generates errors
 leads to bad decisions
 can lead to failure of organization

18. 1. 2 Historical Roots of Database 1. 2
1.2 Historical Roots of Database How modern database evolved from file systems
Managing data with file systems is obsolete
Understanding file system characteristics makes database design easier to understand
Awareness of problems with file systems helps prevent similar problems in DBMS
Knowledge of file systems is helpful if you plan to convert an obsolete file system to a DBMS

19. 1.3 Files and File Systems 1.3.1 Files / Manual File Systems
Collection of file folders kept in file cabinet
Organization within folders based on data’s expected use
(ideally logically related)
System adequate for small amounts of data with few reporting requirements
Finding and using data in growing collections of file folders became time-consuming and cumbersome

20. 1.3 Files and File Systems 1.3.2 File Systems / File-Based-Systems
Conversion from manual to computer system
A collection of application programs that perform services for the end-users.
Could be technically complex, requiring hiring of data processing (DP) specialists

21. 1.3 Files and File Systems 1.3.2 File Systems / File-Based-Systems
A collection of application programs that perform services for the end-users
Each programs manages its own data
Sales application programs
Contracts application programs

22. 1.3 Files and File Systems 1.3.2 File Systems / File-Based-Systems

23. 1.3 Files and File Systems 1.3.2 File Systems / File-Based-Systems
As number of databases increased, small file system evolved
Each file used its own application programs
Each file was owned by individual or department who commissioned its creation

24. 1.3 Files and File Systems 1.3.2 File Systems / File-Based-Systems
As system grew, demand for DP’s programming skills grew
Additional programmers hired
DP specialist evolved into DP manager, supervising a DP department
Primary activity of department (and DP manager) remained programming

25. 1.4 A File System Critique 1.4.1 About Flaws in File System Data Management
Every task requires extensive programming in a third-generation language (3GL)
Programmer must specify task and how it must be done
Modern databases use fourth-generation languages (4GL)
Allow users to specify what must be done without specifying how it is to be done

26. 1.4 A File System Critique 1.4.1 About Flaws in File System Data Management
Time-consuming, high-level activity
As number of files expands, system administration becomes difficult
Making changes in existing file structure is difficult
File structure changes require modifications in all programs that use data in that file
Modifications are likely to produce errors, requiring additional time to “debug” the program
Security features hard to program and therefore often omitted

27. 1.4 A File System Critique 1.4.2 Structural and Data Dependence
Structural dependence
Access to a file depends on its structure
Data dependence
Changes in the data storage characteristics without affecting the application program’s ability to access the data
Logical data format
How the human being views the data
Physical data format
How the computer “sees” the data

28. 1.4 A File System Critique 1.4.3 Field Definitions and Naming Conventions
Flexible record definition anticipates reporting requirements by breaking up fields into their component parts

29. 1.4 A File System Critique 1.4.4 Data Redundancy
same data are stored in many different locations
Data inconsistency
Different and conflicting versions of the same data appear in different places
Island of Information – scattered data locations
Errors more likely to occur when complex
Data redundancy results in data inconsistency
Errors more likely to occur when complex entries are made in several different files and/or recur frequently in one or more files
Data anomalies develop when required changes in redundant data are not made successfully

30. 1.4 A File System Critique 1.4.4 Data Redundancy
Data anomalies
Abnormality
Fosters an abnormal condition by forcing field value changes in many different locations
Types of anomalies:
Modification anomalies
Occur when changes must be made to existing records
Insertion anomalies
Occur when entering new records
Deletion anomalies
Occur when deleting records

31. 1.5 Database System 1.5.1 Database System
Problems inherent in file systems make using a database system desirable
File system
Many separate and unrelated files
Database
Logically related data stored in a single logical data repository

32. 1.5 Database System 1.5.1 Database System
Database Management System (DBMS)
A software that enable user to define, create, maintain and control access to database
software that interacts with the end user application program and database.
manage dB structure
controls access to data
contains query languages
Database
A shared collection of integrated computer structure designed to meet various needs of an organization

33. 1.5 Database System 1.5.1 Database System
Each program shared same data for different user views
Data are save in database and managed by DBMS
Contracts application programs
Sales application
programs

34. 1.5 Database System 1.5.2: Database System Component
an organizations of component that define and regulate the collection, storage, management and use of data within a database environment.
components of a database system:
hardware
software
procedure
people
data
machine components
human components
bridge

35. 1.5 Database System 1.5.2: Database System Component
Hardware
Particular hardware depends on organizations requirements and DBMS model
PC, Web Server, Mainframe
Software
dB software itself
IBM DB2, Access, MS SQL, Oracle
Data
Collections of facts stored in the dB
Acts as a bridge – combine machine components & human components
Operational data and metadata
System catalog

36. 1.5 Database System 1.5.2: Database System Component
Procedure
Instructions and rules that govern design and use of the system
Human
People involve in the system
System administrator
Database administrator (DBAs)
Database designers
System analysts and programmers
End users

37. 1.5 Database System 1.5.3 The Different Between Database and File System
Database Management Systems (DBMS)
a software system that enables user to define, create, maintain and control access to database.
software that interacts with the end user application program and database.
manage dB structure
controls access to data
contains query languages

38. 1.5 Database System 1.5.3 The Different Between Database and File System
Contracts application programs
Sales application
programs
Sales application programs
Contracts application programs

39. 1.5 Database System 1.5.3 The Different Between Database and File System
A Database System
A File System

40. 1.5 Database System 1.5.4 DBMS Functions
DBMS performs functions that guarantee integrity and consistency of data
Data dictionary management
defines data elements and their relationships
Data storage management
stores data and related data entry forms, report definitions, etc.
Data transformation and presentation
translates logical requests into commands to physically locate and retrieve the requested data
Security management
enforces user security and data privacy within database

41. 1.5 Database System 1.5.4 DBMS Functions
Multi-user access control
uses sophisticated algorithms to ensure multiple users can access the database concurrently without compromising the integrity of the database
Backup and recovery management
provides backup and data recovery procedures
Data integrity management
promotes and enforces integrity rules
Database access languages and application programming interfaces
provide data access through a query language
Database communication interfaces
allow database to accept end-user requests via multiple, different network environments

42. 1.5 Database Model 1.5.4 Database Model
Hierarchical Database Model
Represented by a group of records that relates to each others by a pointer
Network Database Model
Based on set theory, a set consists a collection of records
Relational Database Model
Based on the mathematical concept of relational
Object-Oriented Model
Based on object oriented concepts

43. software to implement and used database
Summary
Data
raw facts
Information
reveal meaning of data
Database
shared collection of integrated computer structure designed to meet various needs of organization
DBMS
software to implement and used database

44. Summary Database design defines the database structure.
A well-designed database facilitates data management and generates accurate and valuable information.
A poorly designed database can lead to bad decision making, and bad decision making can lead to the failure of an organization.
Databases were preceded by file systems.
Limitations of file system data management:
requires extensive programming
system administration complex and difficult
making changes to existing structures is difficult
security features are likely to be inadequate
independent files tend to contain redundant data
DBMS’s were developed to address file systems’ inherent weaknesses

45. Exercise 1
What is data redundancy and which characteristics of the file system can lead to it ?
Explain the difference between data and information.
What is the role of a DBMS, and what are its advantages?

46. Exercise 2 What is data independence, and why is it important?
Discuss the different between file based system and database system.
What are the main components of a database system environment?

47. Exercise 3
How many records does the file contain, and how many fields are there per record ?
What problem would you encounter if you wanted to produce a listing by city? How would you solve this problem by altering the file structure?
What data redundancies do you detect, and how could these redundancies lead to anomalies?