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