juniorDatabases
What is an Index in a database?
Updated Apr 28, 2026
Short answer
A data structure that improves the speed of data retrieval operations on a table at the cost of slower writes.
Deep explanation
Deep dive into foundational storage. Understanding how data is stored on disk vs memory. Discussion on the relational model proposed by E.F. Codd.
Real-world example
A library system where books (primary key) are linked to authors (foreign key).
Common mistakes
- Confusing NULL with an empty string.
Follow-up questions
- What is 3NF?