Author Question: Explain the essence of normalization that is implemented through the use of normal forms. What ... (Read 66 times)

bobypop · **on:** Jul 7, 2018

Explain the essence of normalization that is implemented through the use of normal forms.

What will be an ideal response?

Question 2

Given the table CUSTOMER(CustID, Name, PhoneNumber, AccountBalance), write the standard SQL query to retrieve the Name and PhoneNumber of customers with a balance greater than 50.

What will be an ideal response?

tandmlomax84 · **Reply #1 on:** Jul 7, 2018

Answer to Question 1

The essence of normalization is to create relations that contain data on a single theme, and for each row in a relation to contain all the data about that theme for a given entity. This essence is implemented in the normal forms by taking a relation that contains data on more than one theme and splitting it into multiple relations that each contains data on a single theme. The different normal forms protect against the occurrence of modification anomalies. In practice, making sure all relations are in Boyce-Codd Normal Form (BCNF), or in Fourth Normal Form (4NF) if multivalued dependencies are found, insures high reliability of the database.

Answer to Question 2

SELECT Name, PhoneNumber
FROM CUSTOMER
WHERE AccountBalance > 50;