Index Overview

What is it?:

• A stand-alone database structure
• Redundant information, well ordered, that acts as a map/reference to the table

What is it good for?:

• Makes the SELECT/retrieval queries fast

Does it have any disadvantage?:

• It requires disk space
• It requires RAM to take advantage of it entirely
• Causes maintenance overhead for write operations with each INSERT/UPDATE/DELETE

Creating index syntax in POSTGRESQL:

CREATE INDEX e_idx ON users (email)