Normalization is the process of optimizing the relationships between tables in your database. The process involves several stages of splitting a database into smaller components and adding the appropriate relationships.
Many reasons exist for normalizing your database from the outset. Normalization helps to improve the performance of the database by using only the most efficient relationships between tables. It also improves maintainability by reducing repetitive data.
The first stage of normalization involves eliminating any columns that might contain multiple values. For example, consider the following table. This shows a variation on the customers table that also includes the data that is in the customer_contacts table.