fifth normal form การใช้

The third normal form, Boyce Codd normal form, fourth normal form and fifth normal form are special cases of the domain / key normal form.
All tables in this database are in fifth normal form . libUnihan is released as LGPL, while its database, UnihanDb, is released as MIT License.
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 join dependency plays an important role in the Fifth normal form, also known as " project-join normal form ", because it can be proven that if you decompose a scheme R in tables R _ 1 to R _ n, the decomposition will be a lossless-join decomposition if you restrict the legal relations on R to a join dependency on R called * ( R _ 1, R _ 2, \ ldots, R _ n ).