Data and Analytics SQL and Database Fundamentals 3

Question 1

Which SQL command permanently removes a table and its data from the database?

Accepted Answer

DROP

Answer

DROP TABLE removes the entire table definition and all its data permanently from the database.

Question 2

What is the difference between UNION and UNION ALL in SQL?

Accepted Answer

UNION removes duplicates; UNION ALL keeps all rows

Answer

UNION removes duplicate rows from the combined result, while UNION ALL retains all rows including duplicates.

Question 3

Which type of database is best suited for storing unstructured or semi-structured data?

Accepted Answer

NoSQL

Answer

NoSQL databases like MongoDB or Cassandra are designed to handle unstructured, semi-structured, and rapidly changing data models.

Question 4

What does ACID stand for in database transactions?

Accepted Answer

Atomicity, Consistency, Isolation, Durability

Answer

ACID properties (Atomicity, Consistency, Isolation, Durability) guarantee reliable database transaction processing.

Question 5

What is a stored procedure in SQL?

Accepted Answer

A precompiled set of SQL statements stored in the database

Answer

A stored procedure is a precompiled, named block of SQL code stored in the database that can be executed on demand.

Data and Analytics Practice Test