Page 136 - DCAP402_DCAO204_DATABASE MANAGEMENT SYSTEM_MANAGING DATABASE

Unit 8: Normalization

The various normal forms are: Notes
1. First Normal Form
2. Second Normal Form
3. Third Normal Form

4. Boyce-Codd Normal Form
5. Fourth Normal Form
6. Fifth Normal Form

Figure 8.2

Unnormalized Tables

1 NF
2 NF
3 NF
4 NF
5 NF

Normalized Tables

8.2 First Normal Form

The First Normal Form states that:
There should be no repeating groups in a column. In other words, columns in the table should
have atomic values.

Notes Atomic
A column is said to be atomic if the values are indivisible units.
A relation R is said to be in the first normal form (1NF) if and only if every attribute contains
atomic values only.
The table contains atomic values if there is one and only one data item for any given row and
column intersection. Non-atomic values result in repeating groups. A repeating group is the
reoccurrence of a data item or group of data items within records.

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