Introduction to Database System. Introduction to DBMS.

1. Chapter 1:
•The Database Environment
Database System
Thomas Connally and Carolyn Begg
Modern DB Management 7th Ed
red Mc Fadden, Jeffry A Hoffer, and
Merry Prescot

2. • Lecture 1 • Advance Database Systems
•Objectives
Definition of terms
Explain growth and importance of databases
Name limitations of conventional file processing
Identify categories of databases
Explain advantages of databases
Identify costs and risks of databases
List components of database environment
Describe evolution of database systems

3. • Lecture 1 • Advance Database Systems
•Definitions
Database: organized collection of logically
related data
Data: stored representations of meaningful
objects and events
Structured: numbers, text, dates
Unstructured: images, video, documents
Information: data processed to increase
knowledge in the person using the data
Metadata: data that describes the properties
and context of user data

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• Figure 1-1a Data in Context
• Context helps users understand data

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•Graphical displays turn data into useful
information that managers can use for
decision making and interpretation

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

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• File Processing Systems

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•Disadvantages of File Processing
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 of information systems budget

9. • Lecture 1 • Advance Database Systems
•Problems with Data
Dependency
Each application programmer must maintain
their own data
Each application program needs to include
code for the metadata 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

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• Figure 1-2 Three file processing systems at Pine
Valley Furniture
• Duplica
te Data

11. • Lecture 1 • Advance Database Systems
•Problems with Data
Redundancy
Waste of space to have duplicate data
Causes more maintenance headaches
The biggest problem:
When data changes in one file,
could cause inconsistencies
Compromises data integrity

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SOLUTION:
•The DATABASE Approach
Central repository of shared data
Data is managed by a controlling
agent
Stored in a standardized, convenient
form
• Requires a Database Management System (DBMS)

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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

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16. • Lecture 1 • Advance Database Systems
•Elements of the Database
Approach
Enterprise Data Model
Graphical model showing high-level entities and relationships for
the organization
Relational Databases
Database technology involving tables (relations) representing
entities and primary/foreign keys representing relationships
Use of Internet Technology
Networks and telecommunications, distributed databases, client-
server and 3-tier architectures
Database Applications
Application programs used to perform database activities (create,
read, update, and delete) for database users

17. • Lecture 1 • Advance Database Systems

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• One customer may
place many orders, but
each order is placed by
a single customer
 One-to-many
relationship

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• One order has many order
lines; each order line is
associated with a single order
 One-to-many relationship

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• One product can be in
many order lines, each
order line refers to a single
product
 One-to-many
relationship

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• Therefore, one order involves
many products and one product
is involved in many orders
 Many-to-many relationship

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• Relationships established in special columns that provide links between
tables

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• Client/server
system
architecture

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• Application program functions:
• inserting new data, updating existing data,
• deleting existing data, reading data for display

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• Figure 1-9 Workgroup database with local area network

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• Figure 1-10
An enterprise
data
warehouse

29. • Lecture 1 • Advance Database Systems
Components of the
•Database Environment
CASE Tools – computer-aided software engineering
Repository – centralized storehouse of metadata
Database Management System (DBMS) – software for
managing the database
Database – storehouse of the data
Application Programs – software using the data
User Interface – text and graphical displays to users
Data Administrators – personnel responsible for maintaining
the database
System Developers – personnel responsible for designing
databases and software
End Users – people who use the applications and databases

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• Figure 1-11
Components
of the
database
environment

31. • Lecture 1 • Advance Database Systems
•Evolution of DB Systems
Flat files - 1960s - 1980s
Hierarchical – 1970s - 1990s
Network – 1970s - 1990s
Relational – 1980s - present
Object-oriented – 1990s - present
Object-relational – 1990s - present
Data warehousing – 1980s -
present
Web-enabled – 1990s - present

32. • Lecture 1 • Advance Database Systems
•Summary
Definition of terms
Explain growth and importance of databases
Name limitations of conventional file
processing
Identify categories of databases
Explain advantages of databases
Identify costs and risks of databases
List components of database environment
Describe evolution of database systems

33. • Lecture 1 • Advance Database Systems
•Tasks to Do
Read the Chapter 1
Do related exercises of the Chapter
Get ready for Quiz any time
Finalize your project groups and project leaders and also
group’s project proposal.
The project proposal should contain the project description
(see mountain view community hospital project description
in the text book)
Make (not more than 4 slides) of the project description of
each group. You will present it in our next meeting, so that
we should finalize these.