The   Secondly  Normal Form (2NF). A relation is said to be in 2NF if it is in 1NF, and non-key attributes are functionally dependent on the key attribute(s). Further, if the key has more than one attribute then no non-key attributes should be functionally dependent upon a part of the key attributes. Consider, for example, the relation given in table  This relation is in 1NF. The key is (Order no.  Item  code). The dependency diagram for attributes of this relation is shown in figure . The non-key attribute Price/Unit is functionally dependent on Item code which is part of the relation key. Also, the non-key attribute Order date is functionally dependent on Order no. which is a part of the relation key. Thus the relation is not in 2NF. It can be transformed to 2NF by splitting it into three relations as shown in table  

In table 9.3 the relation Orders has Order no. as the key. The relation Order details  has the composite key Order no. and Item code.  

Third Normal form

The Thirdly Normal Form normalization will be needed where all attributes in a relation tuple are not functionally dependent only on the key attribute. If two non-key attributes are functionally dependent, then there will be no unnecessary duplication of data