Database Normalization and 2nf

Question

why is prime->prime dependency doesn't violates 2nf . say table(a,b,c,d,e) and {(a,b),(d,e)} are candidates key and there is a relation from a->d. does it follow functional 2nf rule why?

Comments

2NF removes partial dependency. i.e., if there are no partial dependencies,  then it is in 2NF.

What is the definition of partial dependency ? That decide whether a -> d voilates 2 NF or not.

We just need to stick the definition of partial dependency provided in the standard resources.

Answer 1

See violation of 2NF happens when Some CK partially (particular partial dependency) dertimines a NON PRIME ATTRIBUTES.

2NF only concerns non-prime attributes. It aims to remove partial dependencies of non-prime attributes on candidate keys. Simple, if there is no non prime attributes , then it's in 2NF.

A-->D