3.1. Normalization About

  • Entities - rows in database

  • Attributes - columns in database

  • Normalization is what gives data meaning

  • NF - Normal Form

  • In order to be in 3rd normal form, you need to be in 1st and 2nd NF

  • Core basics: 1st, 2nd, 3rd

  • Exceptions: 4th, 5th

  • 1st: atomic values, unique identifiers (PK), columns with same type

  • 2nd: all data must depend on the Primary Key

  • 3rd: PK define all Non-Key columns, those can't depend on any other Key

  • 4th: No multi-valued dependencies

3.1.1. Glossary

normalization

Database normalization is the process of structuring a database, usually a relational database, in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. Normalization entails organizing the columns (attributes) and tables (relations) of a database to ensure that their dependencies are properly enforced by database integrity constraints. It is accomplished by applying some formal rules either by a process of synthesis (creating a new database design) or decomposition (improving an existing database design). A relational database relation is often described as 'normalized' if it meets third normal form. 1 3

NF

Normal Form

Entity
Entities

Rows in database

Attributes

Columns in database

Table

Database Table

3.1.2. Recap

../../_images/normalform-1st,2nd,3rd.png

Figure 3.5. Image credit: 2

3.1.3. References

1

Database normalization. https://en.wikipedia.org/wiki/Database_normalization

2

Lowgren, Jesper. Database Normalization 1NF 2NF 3NF. Year: 2021. Retrieved: 2022-02-05. URL: https://www.youtube.com/watch?v=SK4H5tTT6-M

3

Codd, E. F. Further Normalization of the Data Base Relational Model. (Presented at Courant Computer Science Symposia Series 6, Data Base Systems, New York City, May 24–25, 1971.) IBM Research Report RJ909 (August 31, 1971). Republished in Randall J. Rustin (ed.), Data Base Systems: Courant Computer Science Symposia Series 6. Prentice-Hall, 1972.