MySQL and mSQL

Normalization

E.F. Codd, then a researcher for IBM, first presented the concept of database normalization in several important papers written in the 1970s. The aim of normalization remains the same today: to eradicate certain undesirable characteristics from a database design. Specifically, the goal is to remove certain kinds of data redundancy and therefore avoid update anomalies. Update anomalies are difficulties with the insert, update, and delete operations on a database due to the data structure. Normalization additionally aids in the production of a design that is a high-quality representation of the real world; thus normalization increases the clarity of the data model.

As an example, say we misspelled “Herbie Hancock” in our database and we want to update it. We would have to visit each CD by Herbie Hancock and fix the artist’s name. If the updates are controlled by an application which enables us to edit only one record at a time, we end up having to edit many rows. It would be much more desirable to have the name “Herbie Hancock” stored only once so we have to maintain it in just one place.

First Normal Form (1NF)

The general concept of normalization is broken up into several “normal forms.” An entity is said to be in the first normal form when all attributes are single-valued. To apply the first normal form to an entity, we have to verify that each attribute in the entity has a single value for each instance of the entity. If any attribute has repeating values, it is not ...