Week 12

This week is the last week in this trimester and this week is the most important week in this trimester. She did the revision all the lessons that she has lectured since the first week. Moreover, I can ask her for more explaining on our assignment (sites.google). She really focuses and wants all the students gain knowledge, can score well in examination and can practice for the real lives as well.

On Thursday, there was a lab class. In this class she provided us one more quiz and she added to teach us one more article was about Relational Database.

What is Data base?

Database: A collection of interrelated data stored together with controlled redundancy to serve one or more applications in an optimal way.

There are 4 components of database:

-          Data item

-          Relationship

-          Constrain

-          Schema

Database Management Systems (DBMS)

The DBMS performs the following five primary functions:

-          Define, create and organise a database

-          Input data

-          Process data

-          Maintain data integrity and security

-          Query database

Example of DBSM

•      Microsoft Access

•      Oracle

•      MySQL

Database System

The DBMS software together with the Database is called a database system. It is a system whose overall purpose is to record and maintain information.

Types of Database Models

•      Hierarchical database: The hierarchical data model organizes data in a tree structure.

•      Network database: Resembles hierarchical model.

•      Relational database: In relational databases, fields can be used in a number of ways (and can be of variable length), provided that they are linked in tables.

•      Object-relational database: Consists of 6 terms are field, record, key field, table, relational database and objects.

Example of relational database