Full-Stack Development Database Design & Management 2

Question 1

What is an ORM (Object-Relational Mapper) used for in full-stack development?

Accepted Answer

Mapping database tables to programming language objects to simplify data access

Answer

Compressing database backups

Answer

Optimizing SQL query execution plans

Answer

Replicating data across multiple database servers

Question 2

Which PostgreSQL feature allows you to store and query JSON data natively?

Accepted Answer

JSONB column type

Answer

TEXT column with manual parsing

Answer

BLOB column type

Answer

XML column with XPATH queries

Question 3

What is database sharding?

Accepted Answer

Horizontally partitioning data across multiple database instances

Answer

Creating read-only replicas of a database

Answer

Encrypting database tables for security

Answer

Compressing old data to archive storage

Question 4

In a relational database, what does a composite primary key consist of?

Accepted Answer

Two or more columns whose combined values uniquely identify a row

Answer

A single auto-incrementing integer column

Answer

A UUID generated at insert time

Answer

A hash of all column values in the row

Question 5

What is the primary difference between a clustered and a non-clustered index?

Accepted Answer

A clustered index determines the physical order of data in the table; non-clustered does not

Answer

Clustered indexes are stored in RAM; non-clustered are on disk

Answer

Non-clustered indexes are faster for all query types

Answer

Clustered indexes can only be created on primary keys

Question 6

Which database isolation level prevents dirty reads but still allows non-repeatable reads?

Accepted Answer

Read Committed

Answer

Read Uncommitted

Answer

Repeatable Read

Answer

Serializable

Question 7

What is the CAP theorem in distributed databases?

Accepted Answer

The principle that a distributed system can only guarantee two of: Consistency, Availability, Partition tolerance

Answer

A formula for calculating optimal cache size

Answer

A rule for normalizing database schemas

Answer

A protocol for encrypting database connections