Node.js Database Integration

Question 1

What is an ORM and why is it used in Node.js applications?

Accepted Answer

Object-Relational Mapping — it lets developers interact with databases using JavaScript objects instead of raw SQL

Answer

An ORM (Object-Relational Mapping) provides a layer between the application and database, allowing developers to work with database records as JavaScript objects rather than writing raw SQL queries.

Question 2

What is connection pooling and why is it important?

Accepted Answer

Reusing database connections instead of creating new ones for each query, improving performance

Answer

Connection pooling maintains a cache of database connections that can be reused, avoiding the overhead of creating and destroying connections for each query, significantly improving performance.

Question 3

What is the 'N+1 query problem' in database-backed applications?

Accepted Answer

When fetching related data requires 1 initial query plus N additional queries for each result

Answer

The N+1 problem occurs when an application executes one query to fetch N records, then executes N additional queries to fetch related data for each record, causing severe performance issues.

Question 4

What is a database migration in the context of Node.js development?

Accepted Answer

A version-controlled script that modifies the database schema in a predictable, repeatable way

Answer

Database migrations are versioned scripts that make incremental changes to the database schema (creating tables, adding columns, etc.) in a controlled, repeatable manner that can be applied across environments.

Question 5

What is the difference between SQL and NoSQL databases in Node.js applications?

Accepted Answer

SQL databases use structured tables with schemas; NoSQL databases use flexible document, key-value, or graph structures

Answer

SQL databases (PostgreSQL, MySQL) use structured tables with predefined schemas and relationships, while NoSQL databases (MongoDB, Redis) offer flexible data models suited for unstructured or rapidly changing data.

Node.js Practice Test

Node.js Practice Test

Node.js Database Integration