The normal forms (NF)
·1st Normal Form (1NF): Eliminate repeating groups such that all record in all tables can be identified uniquely by primary key in each table, in other word all fields other than the primary key most depend on the primary key.
·2nd Normal Form (2NF): All non-key values must fully functionally depend on the primary key. No potential dependencies are allowed. A partial dependency exists when a field is fully dependent on a part of a composite primary key.
·3rd Normal Form (3NF): Eliminate transitive dependencies, meaning that a field is indirectly determined by the primary key. This is because the field is functionally dependent on another field, where as the other field is depend on the primary key.
Boyce-Codd Normal Form (BCNF): Every determinant in a table is a candidate key. If there is only one candidate key. 3NF, BCNF are one and same.