Database Normal Forms

Normalization rules are divided into the following normal forms:

(From No Normalization)

For a table to be in the First Normal Form, it should follow the following 4 rules:

(From 1st)

For a table to be in the Second Normal Form:

(From 2nd)

A table is said to be in the Third Normal Form when:

Boyce and Codd Normal Form is a higher version of the Third Normal form. This form deals with certain type of anomaly that is not handled by 3NF. A 3NF table which does not have multiple overlapping candidate keys is said to be in BCNF. For a table to be in BCNF, following conditions must be satisfied:

A table is said to be in the Fourth Normal Form when,

A table T is in fifth normal form (5NF) or Project-Join Normal Form (PJNF) if it cannot have a lossless decomposition into any number of smaller tables. The case where all the smaller tables after the decomposition have the same candidate key as the table T is excluded.

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