Transcript Pertemuan 23 Object database design (Lanjutan bagian 2) Matakuliah

Matakuliah
Tahun
Versi
: M0174/OBJECT ORIENTED DATABASE
: 2005
: 1/0
Pertemuan 23
Object database design (Lanjutan
bagian 2)
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Mahasiswa dapat Menunjukkan konsep
relational data model (C3)
2
Outline Materi
• Which classes to omit ?
• Effective use of inheritance hierarchies
• Are the classes at the right level of
abstraction ?
• Abstract object are important
3
Which classes to omit ?
• Redundant class denotes a concept that is
already denoted by some other class
• Example
4
Which classes to omit ?
• An Irrelevant term is one that does not
represent useful information from the
perspective of the object database system
• Example
5
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
6
Effective use of inheritance hierarchies
• Inheritance is often described as an is_a
relationship
• Example
7
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
8
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
9
SUMMARY
• Classes to omit include
– Redundant
– Irrelevant
– Too vague
10