Key Technologies

Question 1

When discussing databases in a system design interview, which type is the obvious choice for product design? What about system design?

Answer 1

In general, it can vary, but relational is probably preferred for product; non relational for system design.

Question 2

What is a relational database and why should you use one?

Answer 2

A database that stores data in tables, rows, and columns and requires a well defined schema. Generally they are transactional and have strong consistency guarantees.

If you have well defined schemas, require strong consistency (via ACID), they are good choices.

Question 3

What’s a non relational database? When might those be good choices?

Answer 3

It’s an open-ended term for non-SQL databases (they can come in many forms). They typically have a flexible data model and scale well (due to eventual consistency via BASE).

Question 4

What is blob storage? When should you use it?

Answer 4

Blob storage is when you need to store large, unstructured data (e.g. images, videos, etc.).

Question 5

What are some features of blob storage?

Answer 5

It’s typically highly durable, scalable, cost-efficient, and efficient (re: uploads/downloads).