Database Management System Lecture 1

wakecabbagepatchΛογισμικό & κατασκευή λογ/κού

18 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

103 εμφανίσεις

Database

By:
Manoja

Weerasekara

Road Map

o
Introduction to DBMS


o
Database
Architecture


o
Data
Models


o
Database
Design Methodology




Conceptual
Model




Logical
Model




Physical
Model




Implementation



Road Map


o
Entity Relationship Diagrams



Entities



Relations



Attributes



Mapping
Conceptual model into Relational Schema


o
Data
Normalization



INF



2NF



3NF



Boyce
Codd

Normal Forms



o
Relational
Data Model

Database Management
Systems


Contents:


Databases Overview


Database Concepts


Reasons for a DBMS


Database Models:



Flat databases



Hierarchical databases



Relational databases



Object Oriented databases



Centralized databases


Basic Components of DBMS


Database and information systems security



Structured Query Language (SQL)

Database Concepts


The need of database systems arose in the early 1960s in
response to the traditional file processing system.


In
the
file processing system
, the data is stored in the form of
files, and a number of application programs are written by
programmers to add, modify, delete, and retrieve data to and
from appropriate files.


New
application programs are written
when
needed by the
organization.

Billing

Program

Customer

file

Accounts

receivable

file

Accounts_Payable

Program

Vendor

file

Invoice

file

Sales Order Processing

Program

Customer

file

Inventory

file

Payroll

Program

Employee

file

Purchasing

Program

Buyer

file

Inventory

file

Vendor

file

File Processing Systems

Back

Orders

file

Inventory

Master

file

Customer

Master

file

Inventory

Pricing

file

Employee

Master

file

Order Dept.

Accounting

Dept.

Payroll

Dept.

Ordering

filing

System

Invoicing

System

Payroll

System

Program


A

Program


B

Program


C

Database Approach

Database Overview:


A database is any collection of related
data.





Entity:

Object, Concept or event (subject)



Attribute:

a Characteristic of an entity



Row or Record:

the specific characteristics of one entity



Table:

a collection of records



Database:

a collection of tables

Database Organization/ Database Models :

Flat Databases:

A single kind of record with a fixed number of fields.


Notice the repetition of data, and thus an increased chance of errors.


Database Organization/ Database Models :

Hierarchical Databases:

In this model each entity has only one parent but can have several children.


At the top of hierarchy there is only one entity which is called
Root

Database Organization/ Database Models :

Relational Databases:

In this model data is organized in Two
-
dimensional tables called, relations.


The tables or relation are related to each other.

Database Organization/ Database Models :

Object Oriented Databases:

An
object database

(also
object
-
oriented database
system
) is a database
system
in
which information is represented in the form of objects as used in object
-
oriented
programming.