I'm doing a homework question where I have to convert a database to 1NF, 2NF and 3NF. I have gotten to 2NF and it does not appear to have any transitive dependencies. Does that mean that it is already in 3NF?
Can a 2NF database already be in 3NF?
491 views Asked by wfgeo At
2
There are 2 answers
0
On
Yes. When a relation (variable or value) is in a given normal form it can also be in higher normal forms at the same time. (But beware that sometimes people sloppily say that a relation is in a given normal form but they mean that it's in that normal form but also not any higher one.)
Being in a normal form is a property of a relation. The way they are named, 1-2-3-BCNF-4-5 are stricter and stricter conditions. So when a relation meets one of those conditions it meets all the preceding ones and it might meet later ones. You happen to have a 2NF relation that is also a 3NF relation. Or to put that anther way, you have a 3NF relation that, like every 3NF relation is also in 2NF. You just happened to notice that it was in 2NF before you noticed it was in 3NF.
Yes, unless you missed a transitive functional dependency.