Deck 1: Introduction to Databases and Database Environment

Question 1

A database management system provides a number of facilities that will vary from system to system. Describe the type of facilities you might expect, especially those that aid the initial implementation of a database and its subsequent administration.

Answer 1

Initially, the type of facilities expected should be described. These include: data storage and retrieval, concurrency control mechanism, authorization services, integrity mechanisms and transaction support. The focus is then on facilities such as data definition, which is stored in the catalog, authorization control to manage the users. View definition, transaction support and integrity controls also aid subsequent administration.

Question 2

Discuss the problems that arise when organizations rely upon multiple computerized file systems to store data. Discuss the advantages and disadvantages in using a database management system to carry out the same functions.

Answer 2

For the first part the answer should cover broadly all the problems associated with file-based systems, such as: data duplication, data inconsistency, problems with validation and security, fragmentation of data.
For the second part, the focus is on a DBMS to support the same operations. Advantages include: providing all the data structuring facilities, security mechanisms, integrity mechanisms, backup and recovery facilities, minimal redundancy, data sharing, data independence. Disadvantages include: cost, size, complexity.

Question 3

Applications built around file management systems have often been used to satisfy user requirements. Discuss the problems that arise with such systems, and what advantages a database management system could offer instead.

Answer 3

This answer contains the points made in part one of the previous question and also includes the advantages contained in part two of the previous question.

Question 4

Explain what is meant by a database management system, and contrast it with a File Management System.Give a full account of the type of system structure you might expect for a Database Management System, and outline the type of facilities such a system should provide. If you were in the position of appraising an application for possible implementation using a Database Management System, what aspects of the application would you consider with respect to the advice you might give?

Question 5

Discuss the reasons for the three-level architecture for a Database Management System.

Question 6

Security and recovery are two important functions of a Database Management System, which are also of interest to Database Administration. Various facilities can be provided to aid both these functions. Explain what these facilities are and with examples, show how Database Administration could effectively use them.

Question 7

Explain the purpose of the ANSI/SPARC three-level architecture for a Database Management System, and describe its function giving examples to illustrate your points. Detail the components of a Database Management System, explaining in particular the specific functions of the software modules.

Question 8

A database management system provides a number of facilities, which will vary from system to system. Describe the type of facilities you might expect, especially those that aid the initial implementation of a database and its subsequent administration.