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No, relations describe facts, not things. Heath's theorem means you can decompose a table/relation that has n non-key attributes into n tables. This is someth
by calpaterson 10y ago
No, relations describe facts, not things. Heath's theorem means you can decompose a table/relation that has n non-key attributes into n tables. This is something you have to do for BCNF.
Theoretically it's possible to imagine a normalised relation with 50 columns. In practice a table like that is unusual and suspect (frankly, even in a denormalised design).
- sgeneris 10y agoThere NO relationships whatsoever between normalization and the number of attributes, which are determined by the number of properties that entities have in the real world i.e., the conceptual model.
- calpaterson 10y agoThat is not in conflict with what I said
- sgeneris 10y agoNo. I just thought the clarification was important.
- MustardTiger 10y ago>No, relations describe facts, not things. That is impressively pointless pedantry even for HN, well done. >Theoretically it's possible to imagine a normalised relation with 50 columns Yes, that would be what I said. "You're wrong because exactly what you said is correct!"
- sgeneris 10y agoNo, correctness is not pedantry, except for the ignorant. The database facts are axioms and the facts in query results are theorems -- logical inferences from the axioms. If you don't understand that you have no clue what a relational database is and what a RDBMS does. But hey, you're in the majority. Any linking of number of columns to normalization is pure nonsense. The only accurate thing that can be said is that if you split a relation into multiple projections, by definition each will have less attributes than the original relation. But this is a triviality and it says nothing about the number of columns in the projected relations.
- MustardTiger 10y ago>No, correctness is not pedantry Pedantry is though. And that's what that entirely pointless post was. >Any linking of number of columns to normalization is pure nonsense. That's what I said, that's the point. Don't jump in to a thread you can't be bothered to read.
- sgeneris 10y agoPointless to anybody incapable of getting the point, of which there are too many.