Saturday, May 2, 2009

Week 7-ER Normalization

ER Diagram

ERD in the above, there are 2 that confusion can lead to an error occurs, namely:

1. On the relationship between the entity and the project does not have a clear cardinality.

2. There is a ternary relationship have on the relationship.


Based on the above confusion, the ERD can be improved:

Here the relationship between project entity and eliminates the burden based on business logic, the seal was found by an employee is not a project.

Besides that, here, I also add cardinality value relations between the entity and the project to be 1: N based on the possibility that there is.
Based on the above ERD, we can do process Mapping as follows:

Based on ERD entities dependent on the above which is a weak entity that takes primary key of another entity based on its relation, because here the primary key on the Pegawai entity we use as primary key on table Tanggungan.

Kerja table obtained from the relations between the entities of Pegawai who generate and Proyek a new attribute that is an attribute Jam. This table is based on mapping rules ERD, namely when there is a relationship that has a cardinality value M: N, then the relationship is created a new table.

Based on the above mapping, we can make all the normalization of the table.

1NF

Based on the rules of 1NF, that may not be the kind of field with the multi value, multivalue attributes, and attribute the composite can be formed as 1NF picture above.


2NF
Tanggungan table does not change because each attribute on the table very well depend on the primary key.

3NF

3NF on the changes only at the Pegawai table, because there are non-primary key attribute is dependent on the primary key attribute is non other, in this case KDPos has Alm1 of attributes, so that we make a new table on the table so that the Pegawai is to be:

So that changes to the Pegawai Table,

For other table is not the same as the changes occur Table Section, Projects, and dependent on the Work 2NF.


references:
  1. staf.cs.ui.ac.id/WebKuliah/Anaprancis/2004/laporan3/LAPORAN3_KEL_3.doc -

  2. ER Ngurah Agus Sanjaya. Slide Part 6 - NORMALISASI.
  3. Siti Aminah. Slide Review_Normalisasi_untuk_Vcon_7_des.