Knowledge Base about the database industry: database software, database management systems, database application development, data warehouse, data mining, business intelligence, OLAP, database design, data modeling, data integration, database security.
Database Normalization is a process of eliminating duplicated data in a relational database. The key idea is to relate pieces of data together instead of storing the same data over and over again. Well-normalized databases have a design that reflects the true dependencies between tracked quantities, allowing quick updates to data with little risk of introducing inconsistencies. This not only increases the performance of the Relational DataBase Management System (RDBMS) that is used to warehouse the data, but the ease of accessing relevant data and making connections between data that forms the basis of today's Business Intelligence applications.
There are formal methods for quantifying "how normalized" a relational database is, and these classifications are called normal forms (or NF). Though algorithms exist for converting a given database between forms, these may require splitting existing tables into ones that are re-joined each time a query is issued. This can lead to poor performance, so intentional denormalization is sometimes preferred.
A Simple Guide to Five Normal Forms in Relational Database Theory
Database normalization introduction explaining each of the three normal forms.
Concentrating on the 12 Rules from EF Codd and a succint, informal definition of normalization with examples.
Series of tutorials that explain SQL syntax through interaction with MySQL. Includes information on Joins, Administration (backups, users) and Normalization.
