Give a table of your own that is already in 1NF but not in 2

Give a table of your own that is already in 1NF but not in 2NF, along with the functional dependencies among the attributes of the table drawn as a diagram. Illustrate the process of normalisation of your table to 2NF.

Solution

Second Normal Form :-

A table is said to be in 2NF if and only if :-

* The Table should be in 1NF.

* No non-prime attribute is dependent on the proper subset of any candidate key of table.

Non-Prime Attribute :-

Non-Prime Attibute is an attribute which is not part of any candidate key.

Example :-

In the given table ...

Candidate Keys :- SID,SUB

Non-Prime Attribute :- SAGE

Now we can say that the table is in 1 NF because every attribute has atomic value. But, it is not in 2NF because non prime attribute SAGE is dependent on SID alone which is a proper subset of candidate key, which violates the rule of 2NF. In order to achieve 2NF we can break the table into two tables like below :-