Unit 1

Question 1

Applications of Database Systems

Answer 1

1.Railway Reservation Systems.
2.Banking.
3.Education Sector.
4.Social Media Sites.
5.Airline Reservation Systems.
6.Health care Systems.
7.Telecommunication.
8.E-commerce Websites.

Question 2

Purpose of Database Systems.

Answer 2

The main purpose of database systems is to store, manage and retrive data in efficient way.

In Rdbms data stored as table, which can linked each other through relationships.

This makes it easier to manage large amounts of structured data and ensure data consistency , integrity and security.

Before DBMS exists:

Difficulties in conventional file processing systems:

1.Data redundancy.
2.inconsistency.
3.Difficulty in accessing data.
4.data isolation.
5.integrity problems.
6.security problems.
7.Atomicity of updates.

Question 3

Views of Data

Or

Levels of data abstraction

Answer 3

Views:
Views of data refers to different ways to look at the data and interact with it.

1.Internal view(physical) :

  This tells how the data exactly stored. This is like backend process of database. This is usually doesn't seen by the user. 

2.Conceptual view (logical):

This tells how the data is logically organized. Defines schema, relationships & constraints. It tells How the data is related to each other. 

3.external view(user):

How users sees the data & interact with it. How data is presented to the user.

Question 4

DataBase Languages

Answer 4

Data Definition Language:

It helps to create , modify and delete the structure of the database like table and columns. It commands include CREATE, ALTER, DROP. 

Data Manipulation Language:

It helps store, manage,retrieve the data in the data base. It commands include INSERT, UPDATE, DELETE, SELECT.

Data Control Language:

It controls who can access and manage the database. It commands include GRANT, REVOKE to allow and restrict the permissions.

Question 5

Data Storage and Querying

Answer 5

Functional components of DBMS

i,Storage Manager:

     implements Several data structure. 
   Authorization & integrity manager. 
   Transaction Manager. 
   File manager. 
   Buffer manager. 

ii,Query Processor:

       DDL - interpreter. 
       DML - Compiler. 
        Query Evaluation Engine.