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.
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.
|
“If I had to live my life again, I’d make the same mistakes, only sooner. — Tallulah Bankhead |