1. The document introduces database systems by first discussing file systems and their limitations, such as inconsistent data, inflexibility, and limited data sharing. It explains how database management systems (DBMS) were developed to address these issues. 2. It describes the key components of a database including the data itself, metadata that describes the data, indexes for organizing the data, and applications that interface with the database. A DBMS manages the interaction between end users and the stored data. 3. A well-designed database facilitates effective data management, avoids data redundancy issues, and prevents bad decisions from erroneous data. Understanding file systems provides historical context and lessons for database design.

1. Chapter 1 The Worlds
1 of Database Systems
File Systems and Databases
Prof. Sin-Min Lee
Dept. of Computer Science

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Tuesday Thursday
10:15 – 11:30

3. Your evaluation in this course is determined by:
30%
1
Class Presentation
Presentation report
10%
5%
??!

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6. Text Book
1 NARAYAN S.
UMANATH &
RICHARD W.
SCAMELL, DATA
MODELING AND
DATABASE
DESIGN, 2007
Thomson

7. GOOD REFERENCE
A. Silberschatz, H.F. Korth, S. Sudarshan: Database System
Concepts, 5th Ed., McGraw-Hill, 2006.
1

8. The mediocre teacher tells.
The good teacher explains.
1 The superior teacher
demonstrates.
The great teacher inspires.

9. Files and Databases
File: A collection of records or documents dealing
with one organization, person, area or subject
(Rowley)
1 Manual (paper) files
Computer files
Database: A collection of similar records with
relationships between the records (Rowley)
Bibliographic, statistical, business data, images, etc.

10. Introducing the Database
Major Database Concepts
1
Data and information
Data - Raw facts
Information - Processed data
Data management
Database
Metadata
Database management system (DBMS)

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13. Sales per Employee for Each of ROBCOR’S Two Divisions
1
Figure 1.1

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15. Database Systems
Types of Database Systems
Number of Users
1
Single-user
– Desktop database
Multiuser
– Workgroup database
– Enterprise database
Scope
Desktop
Workgroup
Enterprise

16. Database Systems
Types of Database Systems
Location
1 Centralized
Distributed
Use
Transactional (Production)
Decision support
Data warehouse

17. Database
A Database is a collection of stored operational data
used by the application systems of some particular
enterprise (C.J. Date)
1 Paper “Databases”
Still contain a large portion of the world’s knowledge
File-Based Data Processing Systems
Early batch processing of (primarily) business data
Database Management Systems (DBMS)

18. Why DBMS?
History
50’s and 60’s all applications were custom built for particular
needs
1 File based
Many similar/duplicative applications dealing with collections
of business data
Early DBMS were extensions of programming languages
1970 - E.F. Codd and the Relational Model
1979 - Ashton-Tate and first Microcomputer DBMS

19. File Based Systems
Application File
Delivery
1
Toys
List Addresses
Coal
Estimation Naughty
Just what
asked for Nice Toys

20. From File Systems to DBMS
Problems with file processing systems
Inconsistent data
1
Inflexibility
Limited data sharing
Poor enforcement of standards
Excessive program maintenance

21. DBMS Benefits
Minimal data redundancy
Consistency of data
1
Integration of data
Sharing of data
Ease of application development
Uniform security, privacy, and integrity controls
Data accessibility and responsiveness
Data independence
Reduced program maintenance

22. Terms and Concepts
Data independence
Physical representation and location of data and the use of
that data are separated
1
The application doesn’t need to know how or where the
database has stored the data, but just how to ask for it
Moving a database from one DBMS to another should not have
a material effect on application program
Recoding, adding fields, etc. in the database should not affect
applications

23. Database Environment
1 CASE
Tools
User
Interface
Application
Programs
Repository
DBMS Database

24. Database Components
DBMS
===============
Design tools
1
Table Creation
Form Creation
Query Creation
Report Creation Application
Procedural
Database language
Programs
compiler (4GL)
=============
Run time
Database contains:
Form processor
User’s Data Query processor
User
Metadata Report Writer Interface
Indexes Language Run time Applications
Application Metadata

25. Types of Database Systems
PC databases
Centralized database
1
Client/server databases
Distributed databases
Database models

26. PC Databases
E.g.:
Access
1
FoxPro
Dbase
Etc.

27. Centralized Databases
1 Central
Computer

28. Client Server Databases
Client
1
Client
Network
Database
Server
Client

29. Distributed Databases
Location B
Location C
1 computer
computer
Homogeneous
computer Databases
Location A

30. Distributed Databases
Heterogeneous Client
Or Federated Remote
Databases Comp.
1
Database
Server
Local Network
Comm
Server
Remote
Client Comp.

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34. Introducing the Database
Importance of DBMS
It helps make data management more efficient
1
and effective.
Its query language allows quick answers to ad
hoc queries.
It provides end users better access to more and
better-managed data.
It promotes an integrated view of organization’s
operations -- “big picture.”
It reduces the probability of inconsistent data.

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36. The DBMS Manages the Interaction
Between the End User and the Database
1
Figure 1.2

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38. Introducing the Database
Why Database Design Is Important?
A well-designed database facilitates data
1 management and becomes a valuable information
generator.
A poorly designed database is a breeding ground
for uncontrolled data redundancies.
A poorly designed database generates errors that
lead to bad decisions.

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43. Historical Roots
Why Study File Systems?
It provides historical perspective.
1 It teaches lessons to avoid pitfalls of data
management.
Its simple characteristics facilitate understanding
of the design complexity of a database.
It provides useful knowledge for converting a file
system to a database system.

44. Contents of the CUSTOMER File
1
Figure 1.3

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47. Table 1.1 Basic File Terminology
Data “Raw” facts that have little meaning unless they have been
organized in some logical manner. The smallest piece of data
that can be “recognized” by the computer is a single
character, such as the letter A, the number 5, or some
1
symbol such as; ‘ ? > * +. A single character requires one
byte of computer storage.
Field A character or group of characters (alphabetic or numeric)
that has a specific meaning. A field might define a telephone
numbers, a birth date, a customer name, a year-to-date
(YTD) sales value, and so on.
Record A logically connected set of one or more fields that describes
a person, place, or thing. For example, the fields that
comprise a record for a customer named J. D. Rudd might
consist of J. D. Rudd’s name, address, phone number, date
of birth, credit limit, unpaid balance, and so on.
File A collection of related records. For example, a file might
contain data about ROBCOR Company’s vendors; or, a file
might contain the records for the students currently enrolled
at Gigantic University.

48. Contents of the AGENT File
1
Figure 1.4

49. A Simple File System
1
Figure 1.5

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