CIW CIW Database Design & SQL

Question 1

What is the purpose of a primary key in a relational database table?

Accepted Answer

To uniquely identify each row in the table

Answer

To link two tables with a foreign key relationship

Answer

To define the default value for a column

Answer

To index every column for faster queries

Question 2

Which SQL command is used to retrieve data from a database table?

Accepted Answer

SELECT

Answer

INSERT

Answer

UPDATE

Answer

DELETE

Question 3

What does normalization achieve in database design?

Accepted Answer

Reduces data redundancy and ensures data integrity by organizing tables logically

Answer

Increases the number of tables to speed up queries

Answer

Encrypts sensitive columns automatically

Answer

Merges all related data into a single flat table

Question 4

What is a foreign key in a relational database?

Accepted Answer

A column that references the primary key of another table to establish a relationship

Answer

A secondary index on a frequently queried column

Answer

An encrypted key used to access the database

Answer

A backup copy of the primary key stored in a separate table

Question 5

Which SQL clause is used to filter query results based on a condition?

Accepted Answer

WHERE

Answer

GROUP BY

Answer

ORDER BY

Answer

HAVING

Question 6

What type of SQL JOIN returns only rows that have matching values in both tables?

Accepted Answer

INNER JOIN

Answer

LEFT JOIN

Answer

RIGHT JOIN

Answer

FULL OUTER JOIN