Read:14 | DB Normalization

Article: Database Normalization Explained

Notes from Article:

Database Normalization is basically organizing a database of information into tables and columns with a single purpose.

• Using a 1 purpose table design, you reduce duplicate data in your database
• As tables satisfy successive db normalization forms, they are less prone to modification anamolies
• You want to use Database Normalization because:
  • minimize duplicate data
  • minimize modification issues
  • simplify query searches
• Data Duplication leads to inscreased storage and descreases performance

Let’s use this table as an example for Modification Issues:

- Modification Anomalies make data difficult to maintain when there are changes - Insert Anomaly Ex: We can't record a new sales office until we know the sales person because the primary key is based on Employee ID - Update Anomaly Ex: If the office number changes then we have to make multiple updates instead of one. And if we don't catch all we will have *inconsistencies* :( - Deletion Anomaly Ex: If John retires and we delete his row, we lose info about the NY officce - This is why it's important to have tables serve a single purpose ### Common form of DB Normalization is 1NF, 2NF, 3NF - i.e. The forms are progressive so to qualify for 3rd normal form, a table must satisfy the rules for 2nd normal form, etc. - Below is a screenshot representing the defintion of the 3 Normal Forms: - [Back to Home](README.md)