Question

what is fuctional dependency.explain 2nd normal form

Answer 1

Answer:

In relational database theory, a functional dependency is a constraint between two sets of attributes in a relation from a database. In other words, a function.Second Normal Form (2NF) is based on the concept of full functional dependency. ... A relation that is in First Normal Form and every non-primary-key attribute is fully functionally dependent on the primary key, then the relation is in Second Normal Form (2NF)

Answer 2

Answer:

A functional dependency (FD) is a relationship between two attributes, typically between the PK and other non-key attributes within a table. For any relation R, attribute Y is functionally dependent on attribute X (usually the PK), if for every valid instance of X, that value of X uniquely determines the value of Y.

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