DATABASE MANAGEMENT SYSTEMS

1. Who is a DBA? What are the responsibilities of a DBA? April/May-2011

A database administrator (short form DBA) is a person responsible for the design, implementation, maintenance and repair of an organization's database. They are also known by

the titles Database Coordinator or Database Programmer, and is closely related to the Database

Analyst, Database Modeller, Programmer Analyst, and Systems Manager.

The role includes the development and design of database strategies, monitoring and improving database performance and capacity, and planning for future expansion requirements. They may also plan, co-ordinate and implement security measures to safeguard the database

2. What is a data model? List the types of data model used. April/May-2011

A database model is the theoretical foundation of a database and fundamentally determines in

which manner data can be stored, organized, and manipulated in a database system. It thereby defines the infrastructure offered by a particular database system. The most popular example of a database model is the relational model.

Types of data model used

Ø Hierarchical model

Ø Network model

Ø Relational model

Ø Entity-relationship

Ø Object-relational model

Ø Object model

 3. Define database management system?

Database management system (DBMS) is a collection of interrelated data and a set of programs to access those data.

4. List any eight applications of DBMS.

a) Banking

b) Airlines

c) Universities

d) Credit card transactions e) Tele communication

f) Finance g) Sales

h) Manufacturing

i) Human resources

5. What are the disadvantages of file processing system?

The disadvantages of file processing systems are

a) Data redundancy and inconsistency b) Difficulty in accessing data

c) Data isolation

d) Integrity problems

e) Atomicity problems

f) Concurrent access anomalies

6. What are the advantages of using a DBMS?

The advantages of using a DBMS are a) Controlling redundancy

b) Restricting unauthorized access

c) Providing multiple user interfaces

d) Enforcing integrity constraints. e) Providing backup and recovery

7. Give the levels of data abstraction?

a) Physical level

b) Logical level c) View level

8. Define instance and schema?

Instance: Collection of data stored in the data base at a particular moment is called an Instance of the database.

Schema: The overall design of the data base is called the data base schema.

9. Define the terms

1) Physical schema

2) logical schema.

Physical schema: The physical schema describes the database design at the physical level,

which is the lowest level of abstraction describing how the data are actually stored.

Logical schema: The logical schema describes the database design at the logical level, which

describes what data are stored in the database and what relationship exists among the data.

10. Mention the actors on scene.

Ø Database administrator

Ø Database designer

Ø End users