6 Database Keys Every Data Engineer Should Know | Data Modeling Explained

This video is taken directly from SQLNest's SQL Intermediate Course - if you want to go deeper into data modeling, keys, relationships, and everything else that makes a database actually work in the real world, check out the full course and more on SQLNest.
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In this video, I break down all 6 types of keys you'll run into in SQL and data modeling - using one running example (a customers → orders → order_items schema) so you can see exactly how each key type shows up in a real database, not just in theory.

???? What's covered:
• Primary Key - uniquely identifies each row
• Candidate Key - any column that could have been the primary key
• Foreign Key - links one table to another and enforces referential integrity
• Composite Key - when no single column is unique on its own
• Natural Key - a real-world, business-meaningful identifier
• Surrogate Key - an artificial ID created purely for convenience

⏱️ Timestamps
00:00 Intro
00:32 Primary Key
02:13...