Slide 16.4: First normal form (1NF)

An Example of Database Normalization (Cont.)

First Normal Form (1NF)

The first normal form simply says that each cell of a table should contain exactly one value.

Let’s try to understand this with an example. The following table shows an identified relation for Student Registration for courses.

As you see, a tuple represents a registration that is done for a date.

If the relation is normalized for 1NF, we need to make sure that

No multiple values in intersection of each row and column,
No repeatable groups in attributes (like columns Course_1, Course_2, Course_3, ...),
Order of attributes and tuples are insignificant, and
No duplicate tuples in the relation.

You can see that Course attribute has multiple value that violates the 1NF.

One way to handle it without decomposing the relation is to reorganize the tuples.

Since the relation has no multiple values in intersections and no repeatable groups, it is now a 1NF relation.