Database Design - Normalization & Natural JOIN

Question 1

What is Normalization ?

A.

A. The process of increasing database size to improve performance

B.

B. The process of encrypting data for security

C.

C. The process of organizing data to reduce redundancy and improve data integrity

Explanation: Normalization is a database design technique used to structure tables in a way that:

Reduces data redundancy (duplicate data)

Eliminates unwanted anomalies (insert, update, delete anomalies)

Improves data consistency and integrity

D.

D. The process of backing up the database regularly

Question 2

Why are multiple joins necessary despite normalization?

A.

A) Normalization creates redundancy that requires joining to resolve

B.

B) Normalization separates related data, requiring joins to reconstruct unified views

Explanation: Normalization decomposes one large table into multiple related tables. Joins reconstruct the logical view of interconnected data (employees with their departments and projects) that was split across separate, normalized tables.

C.

C) Joins enforce 3NF constraints in the database

D.

D) Joins are used to eliminate partial dependencies

Question 3

Why are multiple joins necessary despite normalization?

A.

A) Normalization creates redundancy that requires joining to resolve

B.

B) Normalization separates related data, requiring joins to reconstruct unified views

Explanation: Normalization decomposes one large table into multiple related tables. Joins reconstruct the logical view of interconnected data (employees with their departments and projects) that was split across separate, normalized tables.

C.

C) Joins enforce 3NF constraints in the database

D.

D) Joins are used to eliminate partial dependencies

Question 4

What does a **natural join** automatically use to match rows between tables?

A.

A. All columns with the same name

Explanation: Natural join matches rows based on all columns that share the same name across tables, eliminating duplicates in the result.

B.

B. Only the primary key columns

C.

C. User-specified columns in an ON clause

D.

D. Foreign key columns only

Question 5

What is the primary benefit of using table aliases in a natural join query?

A.

A. To rename the output table

B.

B. To clarify column sources, especially for common columns

Explanation: Aliases like `e` for Employees and `d` for Departments help specify which table's columns to use, avoiding ambiguity.

C.

C. To eliminate the need for the NATURAL JOIN keyword

D.

D. To add new columns to the result

📝 Database Design - Normalization & Natural JOIN

Quiz Complete!