Database Normalization- Quick Reference

The Normalization is used to organize data in a DB by eliminating redundant data and ensuring all table relationships make sense   First Normal Form (1NF) First Normal Form ensures there is no repeating groups     * Eliminate duplicative columns from the same table.     * Create separate tables for each group of related data and identify each row with a unique column  or set of columns (the primary key).   ============================================================================ Second Normal Form (2NF) Second normal form (2NF) further addresses the concept of eliminating Redundant Data     * Meet all the requirements of the first normal form.     * Remove subsets of data that apply to multiple rows of a table and place them in separate tables.     * Create relationships between these new tables and their predecessors through the use of foreign keys.   ============================================================================ Third Normal Form (3NF) Third normal form (3NF) further addresses the concept of eliminating Columns which are Not Dependent On the Key     * Meet all the requirements of the second normal form.     * Remove columns that are not dependent upon the primary key.   ============================================================================ Fourth Normal Form (4NF) Finally, fourth normal form (4NF) has one additional requirement:     * Meet all the requirements of the third normal form.     * A relation is in 4NF if it has no multi-valued dependencies.   MoreInfo:- http://www.datamodel.org/NormalizationRules.html http://databases.about.com/od/specificproducts/a/normalization.htm