G. Normalization & Denormalization

1. What is Normalization?

Represents the way of organizing structured data in the database efficiently. It includes the creation of tables, establishing relationships between them, and defining rules for those relationships. Inconsistency and redundancy can be kept in check based on these rules, hence, adding flexibility to the database.

2. What is Denormalization?

Is the inverse process of normalization, where the normalized schema is converted into a schema that has redundant information. The performance is improved by using redundancy and keeping the redundant data consistent. The reason for performing denormalization is the overheads produced in the query processor by an over-normalized structure.

3. What are the various forms of Normalization?

Lets use an example to illustrate the various forms of normalization. Below is a table with sales records of gaming consoles and their details.

1NF First Normal Form

• Each cell to be single valued
• Entries in a column are the same types
• Rows uniquely identified (add Unique ID or add more columns to make unique)

2NF Second Normal Form

• All attributes (non-key columns) are dependent of the key

3NF Third Normal Form

• All fields (columns) can be determined only by the key in the table and no other column

4NF Fourth Normal Form

• No multi-valued dependencies