Sunday, May 3, 2009

Normalization Quiz

The Erd :

First Normal Form (1NF)

On first normal form still have a lot of weakness, such us:
  • Insert, we can not only inserting NOPEG and NAPEG without their PROYEK, so we can inserting their attribute if there is PROYEK.
  • Update, depend on the table above, many attribute written recurring repeat, if there is updating attribute so all the same attribute must be update.
  • Delete, when one record vanished, so all data in that record will be vanished though the data still needed.
  • UMUR attribute must not be written, because every date of now at reducing attribute TGLLAH so will be result attribute UMUR.

Second Normal Form (2NF)

Second normal form (2NF) is a normal form used in database normalization. A table that is in first normal form (1NF) must meet additional criteria if it is to qualify for second normal form. Specifically: a 1NF table is in 2NF if and only if, given any candidate key and any attribute that is not a constituent of a candidate key, the non-key attribute depends upon the whole of the candidate key rather than just a part of it.
In slightly more formal terms: a 1NF table is in 2NF if and only if none of its non-prime attributes are functionally dependent on a part (proper subset) of a candidate key. (A non-prime attribute is one that does not belong to any candidate key.) Note that when a 1NF table has no composite candidate keys (candidate keys consisting of more than one attribute), the table is automatically in 2NF.

In the second normal form, table of pegawai increased to 2 table.

Third Normal Form (3NF)

Normal form 3NF fufilled if have fulfilled form 2NF, and otherwise there is attribute of is non key primary owning depended to attribute of is non the other key primary.