Back-End Development Development 5

Question 1

Which back-end pattern involves a service publishing events that other services consume asynchronously?

Accepted Answer

Event-Driven Architecture

Answer

Event-Driven Architecture decouples services by having producers publish events to a broker (e.g., Kafka, RabbitMQ) that consumers subscribe to independently.

Question 2

What is the key difference between symmetric and asymmetric encryption in back-end security?

Accepted Answer

Symmetric uses the same key for encryption and decryption; asymmetric uses a public/private key pair

Answer

Symmetric encryption uses one shared key for both operations (fast, good for bulk data), while asymmetric uses a key pair where the public key encrypts and the private key decrypts.

Question 3

In GraphQL, what is the purpose of a resolver function?

Accepted Answer

To fetch or compute the data for a specific field in a query

Answer

A resolver is a function that returns the data for a specific GraphQL field, fetching it from a database, API, or any other data source.

Question 4

Which technique prevents SQL injection attacks in back-end code?

Accepted Answer

Using parameterized queries or prepared statements

Answer

Parameterized queries separate SQL code from user-supplied data, so the database driver handles escaping and the input can never alter query structure.

Question 5

What does eventual consistency mean in a distributed back-end system?

Accepted Answer

Given enough time without new writes, all nodes will converge to the same value

Answer

Eventual consistency is a guarantee that, absent further updates, all replicas will eventually converge to the same state, trading immediate consistency for higher availability.

Back-End Development Practice Test

Back-End Development Practice Test

Back-End Development Development 5