Database Approach & Conceptual Issues

Question 1

What is a File-Based system?

Answer 1

A collection of application programs that perform services for end users. E.g reports Each program defines and manages its own data

Question 2

What are the limitations of using the File-Based approach?

Answer 2

• each program maintains its own set of data, so users of one program may be unaware of useful data help by other programs
• same data is held by different programs, wasting space and different values or formats for same item
• file structure is defined in program code
• program is written in different languages, so cannot easily access other files

Question 3

What is Database?

Answer 3

A shared collection of logically related data, along with its description designed to meet information needs for an organisation.

Question 4

Why use Database approach?

Answer 4

• definition of data is embedded in application programs rather than being sorted separately and independently.
• no control over access and manipulation of data beyond imposed by application programs

Question 5

What is a Database Management System?

Answer 5

A software system that enables users to define, create, maintain and control access to database.

Question 6

What is “Views”?

Answer 6

A feature that allows each user to have their own view of the database.

Question 7

What are the advantages of Database Management System?

Answer 7

• reduce complexity
• provide a level of security
• provide mechanism to customize the appearance of the database
• present consistent, unchanging picture of database structure, even if underlying database is changed

Question 8

What are the components of DBMS?

Answer 8

Hardware
Software
Data
Procedures

Question 9

What is the Hardware component?

Answer 9

ranges from a PC to a network of computers

Question 10

What is the Software component?

Answer 10

DBMS, OS, Network Software and application programs.

Question 11

What is the Procedure component?

Answer 11

Instructions and rules applied to the design and use of the database and DBMS

Question 12

What are the roles in Database Environment Users?

Answer 12

Application Programmers
Sophisticated Users
Specialized Users
Stand-alone Users
Native Users

Question 13

What is the Application Programmer role?

Answer 13

Developers who interact with the database by means of DML queries, which are written in application programs such as C++, C, Java etc. The queries convert into an object code to communicate with databases.

Question 14

Give an example of what an Application Programmer does.

Answer 14

Writing a C program to generate a report of employees who work in certain departments require a query to get h data from a database, which includes SQL query with C program.

Question 15

What is the Sophisticated User role?

Answer 15

Database developers who write SQL queries to select/insert/delete and update data. They do not use applications or programs to request for database. They directly interact with databases by means of query language like SQL.

Question 16

What is the Specialized User role?

Answer 16

Similar to Sophisticated user but writes special database application programs. They are developers who create complex programs to the requirement.

Question 17

What is the Stand-Alone user role?

Answer 17

Has stand-alone database for personal use. The databases will have readymade database packages which include menus and graphical interfaces.

Question 18

What is the Native User role?

Answer 18

Users who use existing applications to interact with the database. E.g online library systems, ticket booking systems, ATM etc.

Question 19

What are the roles of Database Environment Administrators?

Answer 19

Administrative DBA
Development DBA
Database Architect
Data Warehouse DBA
Application DBA
OLAP DBA

Question 20

What is the Administrative DBA role?

Answer 20

Concerns on installing and maintaining DBMS servers. Prime tasks include installing, backups, recovery, security, replications, memory management, configurations and tuning

Question 21

What is the Development DBA role?

Answer 21

Responsible for creating queries and procedure for the requirement.

Question 22

What is the Database Architect role?

Answer 22

Creates and maintains users, roles, access rights, tables, views, constraints and indexes. Mainly responsible for designing the structure of the database depending on the requirements. The structures will be used by developers and development DBA to code.

Question 23

What is the Data Warehouse DBA role?

Answer 23

Maintains data and procedures from various sources in data warehouse. Sources can be:

• files
• COBOL
• any other programs

Question 24

What is Application DBA role?

Answer 24

Acts like a bridge between application program and database. They ensure:

• all application programs are optimized to interact with the database
• all activities from installing, upgrading and patching, maintain, backup, recovery to executing records works without errors

Question 25

What is the OLAP DBA role?

Answer 25

Responsible for installing and maintaining database in OLAP systems.

Question 26

What are the advantages of DBMS?

Answer 26

• allows data redundancy control
• more information from same amount of data
• allows data sharing
• improves data integrity
• improves security
• economy of scale
• improves maintenance through data independence

Question 27

What are the disadvantages of DBMS?

Answer 27

• complexity
• costly
• higher chance of failure
• requires highly skilled administration