Database Normalization – First Normal Form

In the previous post we learnt about database normalization. Here we are going to learn about the First Normal form. Normalization of table starts with first normal form.

Conditions for first normal form

1. Single valued attributes: It means every cell in a table must contains only a single value not more than that.
2. Every column must have a unique name.

Let’s understand it with an example. Consider below relation or table. This table contains data for students.



Student_ID Student_Name Mobile_Number
478 John 124587963, 127855472
654 Alex 324786897
124 Ramesh 147895554, 678945558

In the above table we can see that all our column names are unique but as you noticed a student can have more than one mobile number. So here a cell contain multiple values which are not allowed in 1NF.

What to do?

The solution is simple just break the values, and create a row for each values. See the table below.

Student_ID Student_Name Mobile_Number
478 John 124587963
478 John 127855472
654 Alex 324786897
124 Ramesh 147895554
124 Ramesh 678945558

Now every cell is single valued. But it increases redundancy in table. We will use other normal forms to reduce these problems.

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