. Database normalization is a technique for designing relational database tables to minimize duplication of information and, in so doing, to safeguard the database against certain types of logical or structural problems,namely data anomalies.
1NF Eliminate Repeating Groups - Make a separate table for each set of related attributes, and give each table a primary key.
2NF Eliminate Redundant Data - If an attribute depends on only part of a multi-valued key, remove it to a separate table.
3NF Eliminate Columns Not Dependent On Key - If attributes do not contribute to a description of the key, remove them to a separate table.
BCNF Boyce-Codd Normal Form - If there are non-trivial dependencies between candidate key attributes, separate them out into distinct tables.
4NF Isolate Independent Multiple Relationships - No table may contain two or more 1:n or n:m relationships that are not directly related.
5NF Isolate Semantically Related Multiple Relationships - There may be practical constrains on information that justify separating logically related many-to-many relationships.
ONF Optimal Normal Form - a model limited to only simple (elemental) facts, as expressed in Object Role Model notation.
DKNF Domain-Key Normal Form - a model free from all modification anomalies.
Normalization is the process of efficiently organizing data in a database. There are two goals of the normalization process: eliminating redundant data (for example, storing the same data in more than one table) and ensuring data
dependencies make sense (only storing related data in a table). Both of these are worthy goals as they reduce the amount of space a database consumes and ensure that data is logically stored.
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