Normal Form II

Back to: DATA PROCESSING SS 2

 

Welcome to class! 

In today’s class, we will be talking more about normal form. Enjoy the class!

Normal Form II

Types of Normal Form

• First Normal Form (1NF):

First Normal Form (1NF) says that all column values must be atomic. 1NF dictates that for every row by column position in a given table, there exist only one value, not an array or list of values i.e in 1NF, the following rules are observed;

1. Eliminating repeating information
2. Create separate tables for related data.

• Second Normal Form (2NF):

The second normal form (2NF) further addresses the concept of removing duplicate data. The rule for the second normal form is;

1. Remove subsets of data that apply to multiple rows of a table and place them in a separate table.
2. Create relationships between these new tables and their predecessors through the use of foreign keys.

 Evaluation

1. State the rules for carrying out the first normal form (1NF).
2. State the rules for carrying out the second normal form (2NF).

NOTE: The 2NF attempts to reduce the amount of redundant data in a table by extracting it, placing it in a new table(s) and creating relationships between those tables.

• Third Normal Form (3NF):

There are two basic requirements for a database to be in Third Normal Form:

1. The requirements of both 1NF and 2NF must have been met.
2. Remove columns that are not fully dependent upon the primary key.

• The Fourth Normal Form (4NF) and Fifth Normal Form (5NF):

The fourth and the fifth normal form are beyond the scope of this syllabus.

Note: Both the fourth and the fifth normal form still follows the goal of the normalization process, which are;

1. eliminating redundant data.
2. ensuring data dependencies make sense.

General evaluation

1. State the goal of the normalization process.
2. State the rules for carrying out the first normal form (1NF)

Weekend assignment

1. State the rules for carrying out the first normal form.
2. State the rules for carrying out the second normal form.

 

In our next class, we will be talking more about Normal Form.  We hope you enjoyed the class.

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