Normalization is a process used in database design to structure a relational database in accordance with a series of normal forms to reduce data redundancy and improve data integrity. The process involves organizing the columns (attributes) and tables (relations) of a database to ensure that their dependencies are properly enforced by database integrity constraints. Normalization can be accomplished by applying some formal rules either by a process of synthesis (creating a new database design) or decomposition (improving an existing database design) . The objectives of normalization include:

• Reducing data redundancy
• Improving data consistency and accuracy
• Improving data integrity
• Making the database more flexible by eliminating redundancy and inconsistent dependency
• Allowing the structure of a fully normalized database to be extended to accommodate new types of data without changing existing structure too much

Normalization rules are divided into normal forms, and each rule is called a "normal form". If the first rule is observed, the database is said to be in "first normal form." If the first three rules are observed, the database is considered to be in "third normal form". Although other levels of normalization are possible, third normal form is considered the highest level necessary for most applications.

Normalization is also used in statistics and applications of statistics, where it can have a range of meanings). In the simplest cases, normalization of ratings means adjusting values measured on different scales to a notionally common scale, often prior to averaging). In another usage in statistics, normalization refers to the creation of shifted and scaled versions of statistics, where the intention is that these normalized values allow the comparison of corresponding normalized values for different datasets in a way that eliminates the effects of certain gross influences, as in an anomaly time series).

Normalization of data in a database has several advantages, including utilizing database or data redundancy through normalization, eliminating duplication, and making it simpler to examine data to enhance a companys operations. Through a set of guidelines (called "normal forms"), the normalization process seeks to guarantee that the consistency of the database is maintained regardless of whether any data is changed, added, or destroyed.