Rules of 1st Normal Form
- Each table should contain a single value.
- Each record needs to be unique.
Table 1 after applying 1st Normal Form:
Full Name | Institute | Subject | Result |
---|---|---|---|
Naveen Kumar | IIT Delhi | DBMS | Pass |
Naveen Kumar | IIT Delhi | OS | Pass |
Utkarsh Tiwari | IIT Bombay | CN | Fail |
Utkarsh Tiwari | IIT Bombay | COA | Fail |
Utkarsh Tiwari | IIT Kanpur | OS | Fail |
Consider the table 2 shown below,
Full Name | Institute | Subject | Result |
---|---|---|---|
Utkarsh Tiwari | IIT Bombay | COA | Fail |
Utkarsh Tiwari | IIT Kanpur | OS | Fail |
Here, People having the same name are from different institutes. So, we require Full Name and Institute to Identify a Row of the database. For this, we have to remove Partial Dependency.
Let’s look at the 2nd Normal Form.
Normalization Process in DBMS
Pre-Requisite: Introduction to Database Normalization
Database Normalization is a stepwise formal process that allows us to decompose database tables in such a way that both data dependency and update anomalies are minimized. It makes use of functional dependency that exists in the table and the primary key or candidate key in analyzing the tables. Normal forms were initially proposed called
Subsequently, R, Boyce, and E. F. Codd introduced a stronger definition of 3NF called Boyce-Codd Normal Form. With the exception of 1NF, all these normal forms are based on functional dependency among the attributes of a table. Higher normal forms that go beyond BCNF were introduced later such as Fourth Normal Form (4NF) and Fifth Normal Form (5NF). However, these later normal forms deal with situations that are very rare.
Now, we are going to describe the process of Normalization by considering an Example. Let us look into that.