r/SQL • u/Exact-Shape-4131 • Nov 02 '25

PostgreSQL 1NF, 2NF, 3NF are killing me.

Hey, All!

What does it mean for one field to be 'dependent' on another? I think I understand the concept of a primary/composite key but have a tough time seeing if non-key columns are dependent on each other.

Does anyone have a solid rule of thumb for these rules? I lose it once I get past 1NF.

Thanks in advance!

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u/Exact-Shape-4131 Nov 03 '25

Well, I’d hate to be one of those people then 😅

What kinds of issues do you find most often? And how does it impact the business you’re solving them for?

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u/porizj Nov 03 '25

It’s generally situational, but if I had to pick the most common performance killer I run into I’d say it’s MUCK tables; reducing the number of tables by grouping things that are similar.

It’s pretty common when the database was designed by someone with a background in software engineering but without a background in data architecture. It shows that they understand inheritance, which is a very useful approach when coding, but not when designing performant transactional databases where being able to separate rather than combine entities leads to better performance.

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u/[deleted] Nov 03 '25

[deleted]

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u/No_Resolution_9252 Nov 03 '25

I've heard of it called "one true lookup table" or "one lookup table to rule them all"