1 Pertemuan 23 Object database design (Lanjutan bagian 2) Matakuliah: M0174/OBJECT ORIENTED DATABASE Tahun: 2005 Versi: 1/0

2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Mahasiswa dapat Menunjukkan konsep relational data model (C3)

3 Outline Materi Which classes to omit ? Effective use of inheritance hierarchies Are the classes at the right level of abstraction ? Abstract object are important

4 Which classes to omit ? Redundant class denotes a concept that is already denoted by some other class Example

5 Which classes to omit ? An Irrelevant term is one that does not represent useful information from the perspective of the object database system Example

6 Which classes to omit ? A term is Too vague if the concept that it denotes is too general to be useful within the database Example

7 Effective use of inheritance hierarchies Inheritance is often described as an is_a relationship Example

8 Are the classes at the right level of abstraction ? Abstraction is the representation of something, by focusing only on that which is important and ignoring irrelevant detail Example

9 Abstract object are important Another problem can be that tangible objects may seem more real and be easier to identify as objects than concepts Example

10 SUMMARY Classes to omit include –Redundant –Irrelevant –Too vague