lecture 1on dbms (sql*plus)

8/9/2019 Lecture 1on DBMS (sql*plus)

1/22

Database Technologies - DAC 2105

By Miss Esha Ramtahal

Lecture 1

Introduction to Database


2/22

Introduce database and its users

To discuss about the predecessor of thedatabase system the file-based systemTo study the database approachTo compare and contrast between the

database system and the file-basedsystem

Objectives


3/22

What is Data?

Data are raw facts

What is information?Processed data

Information = data + meaning



4/22

What is a Database?

What is a Database ManagementSystem (DBMS) ?

What is a Database System?



5/22

What is a Database?

Its a collection of data stored in an

organized fashion. The data is stored

as Tables inside of a database.

A database is a collection of datafor one or more multiple uses.

One way of classifying databasesinvolves the type of content, forexample: bibliographic, full-text,

numeric, image.


6/22

DBMS

A database management system (DBMS) consistsof software that organizes the storage of data.

A DBMS controls the creation, maintenance, anduse of the database storage structures of socialorganizations and of their users.

It allows organizations to place control of

organization wide database development in thehands of Database Administrators (DBAs) andother specialists.

In large systems, a DBMS allows users and

other software to store and retrieve data in astructured way.


7/22

Database Processing

Data Entry& Reports

Data Entry& Reports

DBMS Data

Sales

dept

Marketingdept

Database

Sales application programs

Marketing application programs

Fried Noodles Company Ltd.


8/22

Some examples are:

At the supermarket

Using credit card to make a purchase

By travel agencies

At the library

Uses of Database


9/22

The File-Based System

A collection of application programsthat perform services for the end-userssuch as the production of reports.

Each program defines and managesits own data.

Predecessor of Database System


10/22

File-Based System

Data Entry& Reports

Data Entry& Reports

Sales

dept

Marketingdept

Sales application programs

Marketing application programs

Data

Data Sales Files

Mkt. Files

FileDefinition

File

Definition

Data

Sales Files


11/22

Activity

Discuss the limitations of the file-based system each application program defines and managesits own data.

Data Entry& Reports

Salesdept

Marketingdept

Sales applicationprograms

Marketing applicationprograms

Data

Data SalesFiles

MktFiles

FileDefinition

Data Entry& Reports

FileDefinition

Data

Sales

Files


12/22

Duplication of data

Separation/isolation of data Data dependence Incompatible file formats Fixed queries

Limitations of File-Based System


13/22

The database is a collection of related

data which with the use of a DBMScan be used simultaneously by manydepartments and users.

The Database Approach

Dept 1 Database

Dept 2

Dept 3

DBMS


14/22

Allows users to define a database,

usually through a Data DefinitionLanguage (DDL)

Allows users to insert, update, delete,

and retrieve data from a database,usually through a Data ManipulationLanguage (DML)

DBMS - Facilities


15/22

Other Facilities

A security systemAn integrity systemA concurrency control system

A recovery control systemA user-accessible catalogue

DBMS


16/22

5 major components are:

1. Hardware2. Software3. Data4. Procedures

5. People

DBMS Environment


17/22

DBMS Environment

SoftwareHardware Procedures People

Data

Machine HumanBridge


18/22

Activity

What are the advantages of a DBMS?

Hint: limitations of the file-based system.


19/22

Control of data redundancyData consistency

More information from the same amount ofdataData IndependenceSharing of dataImproved data integrityImproved data accessibility and

responsivenessIncreased productivityIncreased concurrencyImproved backup and recovery servicesImproved security

DBMS Advantages


20/22

Complexity Size - disk space, memory

Cost of DBMSs Additional hardware costs Cost of conversion Performance Higher impact of a failure

DBMS Disadvantages


21/22

What is a database

Uses of a database File-based system The database approach Advantages & Disadvantages of the

DBMS

Recap


22/22

~End of Lecture~

Thank you

lecture 1on dbms (sql*plus)

Documents