DBMS Database Management System - Technical Questions and Answers

DBMS - Database Management System
DBMS - Basics

101.	What are the four objectives of the selection of a data type?
	Answer: A data type should be selected so that all possible values are represented using minimal storage space. The data type should help to ensure data integrity and support all possible data manipulations (i.e., cannot place a letter in a field such as salary where a number is required). Workspace Report errors ... Name : Email: View Answer

102.

Describe the four types of indexes.

103.	What is denormalization and why would someone consider doing so?
	Answer: Denormalization is the process of taking normalized relations and changing them so that they are not longer normalized. This process may lead to anomalies and create data redundancy as negative consequences. However, the revised relations should improve database performance. Workspace Report errors ... Name : Email: View Answer

104.

Compare a hierarchical and network database model?

105.

Describe the differences between vertical and horizontal portioning.

106.	Explain the difference between a dynamic and materialized view.
	Answer: A dynamic view may be created every time that a specific view is requested by a user. A materialized view is created and or updated infrequently and it must be synchronized with its associated base table(s). Workspace Report errors ... Name : Email: View Answer

107.	Discuss some of the techniques that can be used to tune operational performance.
	Answer: Choosing primary and secondary keys can increase the speed of row selection, joining, and row ordering. Selecting the appropriate file organization for base tables and indexes can also improve performance. Clustering related rows together and maintaining statistics about tables and indexes can lead to increased efficiency. Workspace Report errors ... Name : Email: View Answer

108.	Briefly describe the three types of SQL commands.
	Answer: Data definition language commands are used to create, alter, and drop tables. Data manipulation commands are used to insert, modify, update, and query data in the database. Data control language commands help the DBA to control the database. Workspace Report errors ... Name : Email: View Answer

109.

What are the steps to follow when preparing to create a table?

110.	What are some disadvantages of a standard language such as SQL?
	Answer: A standard language can hinder the effort to create a new language. One standard is never enough to meet all of the business needs. A standard can be a compromise among interested parties which can cause the standard to not be ideal. If a standard is altered by some, than portability between platforms could be hurt. Workspace Report errors ... Name : Email: View Answer