John works as a Database Administrator for Bluewell Inc. The company has a SQL Server database. A
table in the database has a candidate key and an attribute that is not a constituent of the candidate
key. The non-key attribute depends upon the whole of the candidate key rather than just a part of it.
Which of the following normal forms is represented in the scenario?

A.
4 NF

B.
2 NF

C.
1 NF

D.
3 NF

Explanation:
Second normal form (2NF) is used in database normalization. A table that is in first normal form
must meet additional criteria if it is to qualify for second normal form. Specifically, a 1NF table is in
2NF if and only if, given any candidate key and any attribute that is not a constituent of a candidate
key, the non-key attribute depends upon the whole of the candidate key rather than just a part of it.
Answer C is incorrect. The 1NF is a normalization form in which each column in a row contains a
single value, i.e., each attribute of the entity is single valued. Single valued attributes are also known
as atomic attributes, as they cannot be decomposed into smaller units. There are mainly three kinds
of attributes that prevent a table from being in the first normal form. They are as follows:
Composite attributes
Plural attributes (attributes that have more than one value)
Attributes with complex data types
The table below is in 1 NF, as all the columns in each row contain a single value.

Answer D is incorrect. Third normal form (3NF) is used in database normalization. A table is in 3NF if
and only if the relation S (table) is in second normal form (2NF) and every non-prime attribute of S is
non-transitively dependent on every key of S.
Answer A is incorrect. Fourth normal form (4NF) is a normal form used in database normalization.
Introduced by Ronald Fagin in 1977, 4NF is the next level of normalization after Boyce-Codd normal
form (BCNF). Whereas the second, third, and Boyce-Codd normal forms are concerned with
functional dependencies, 4NF is concerned with a more general type of dependency known as a
multivalued dependency. Symbolically, it can be represented as follows:
If A -> > B|C, then A -> B and A -> C
Here, A, B, and C are attributes.