When to use SQL vs NoSQL in HLD - Quick Revision & Key Differences

Recall & Review

beginner

What is SQL and when is it best used?

SQL is a language for managing structured data in relational databases. It is best used when data is organized in tables with clear relationships, and when you need strong consistency and complex queries.

beginner

What is NoSQL and when is it best used?

NoSQL refers to databases that store data in flexible ways like documents, key-value pairs, or graphs. It is best used when data is unstructured or changing fast, or when you need to scale easily across many servers.

intermediate

Why choose SQL for financial applications?

Financial applications need accurate, consistent data and complex transactions. SQL databases provide strong rules to keep data correct and safe, making them a good choice.

intermediate

When is NoSQL better for big data?

NoSQL databases handle large volumes of varied data quickly and can spread data across many machines. This makes them better for big data and real-time web apps.

beginner

What is a key difference in data structure between SQL and NoSQL?

SQL uses tables with rows and columns, while NoSQL uses flexible formats like documents or key-value pairs, allowing easier changes to data structure.

Which database type is best for structured data with clear relationships?

A SQL

B NoSQL

C Flat files

D In-memory cache

SQL databases organize data in tables with relationships, making them ideal for structured data.

When should you consider using NoSQL databases?

A When data is unstructured or rapidly changing

B When you need complex joins

C When data is highly structured and consistent

D When you want to use SQL queries

NoSQL is good for unstructured or fast-changing data and flexible schemas.

Which database type is better for financial transactions requiring strong consistency?

A NoSQL

B Key-value store

C Document store

D SQL

SQL databases provide strong consistency and transaction support needed for financial data.

What is a common feature of NoSQL databases?

A Fixed schema

B Flexible data models

C Only supports SQL queries

D Data stored only in tables

NoSQL databases allow flexible data models like documents or key-value pairs.

Which scenario favors SQL over NoSQL?

A Real-time analytics on huge data streams

B Simple key-value caching

C Complex queries on related data

D Storing large files

SQL is better for complex queries involving related data.

Explain when you would choose SQL over NoSQL for a project.

Think about data organization and reliability needs.

Describe situations where NoSQL databases provide advantages.

Consider data variety and growth.