##### Lecture on First Normal Form (1NF)
Content covered:

First Normal Form (1NF):
The following criterias must be satisfied for 1NF.

1. Values of each attribute is atomic.
2. No composite values
3. All entries in any column must be of the same kind
4. Each column must have a unique name
5. No two rows are identical

Consider the below Student table

 Roll Name Courses 101 Asif DBMS, CN, CD, SE 102 Amit CO, OS 103 Arpit CD, OS, CN, DBMS

Here you can see that column Courses contain multiple values in a single rows. This is not allowed in 1NF.
We can convert this table into 1NF as below,

 Roll Name Courses 101 Asif DBMS 101 Asif CN 101 Asif CD 101 Asif SE 102 Amit CO 102 Amit OS 103 Arpit CD 103 Arpit OS 103 Arpit CN 103 Arpit DBMS

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Manu F Gomez 28 Jan 2017 11:49 am

Sir, how is BC a candidate key?. candidate key means a minimal super key right. A is a candidate key, as it is a superkey and has minimal set of attributes. So how BC becomes candidate key as it does not have minimal set of attributes.?

Sumit Verma 14 Apr 2017 12:55 pm

@manufg
Candidate key is the minimal key not a key with minimum attributes.
Here A is candidate key, so any superset of attribute A will be superkey not a candidate key.
BC is not a superset of A and if we can get all the attributes from BC then yes, BC will be candidate key.

shweta 30 Apr 2017 04:28 pm

sir after resolving the first relation ... in 2nd relation which will be the primary key???