Matakuliah
Tahun
Versi
: M0174/OBJECT ORIENTED DATABASE
: 2005
: 1/0
Pertemuan 4
Object Oriented Concept
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Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Mahasiswa dapat Menjelaskan konsep
berorientasi objek (C2)
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Outline Materi
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Abstraction
Encapsulation
Information hiding
Methods
Message
Inheritance
Polymorphism
Dynamic binding
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Abstraction
• Abstraction is a process of identifying the
essential aspects of an entity and ignoring
the unimportant properties.
• There are two fundamental aspect of
abstraction:
– Encapsulation
– Information Hiding
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Encapsulation
• The concept of encapsulation means that an
object contain both the data structure and the
set of operation that can be used to manipulate
it.
• The concept of information hiding means that we
separate the external aspect of an object from its
internal details, which are hidden from the
outside world. In this way the internal details of
an object can be changed without effecting the
application that use it.
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Information hiding
• There are two views of encapsulation:
– Object Oriented Programming Language view.
– Database adaptation view.
• In OPPL encapsulation is achieved through
Abstract Data Type (ADT). In this view an object
has an interface part and an implementation
part.
• The interface provide specification of the
operations that can be performed on the object.
The implementation part consist of the data
structure for ADT and the functions that realize
the interface. Only interface part is visible to
other object or user
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• In the database view, proper
encapsulation is achieved by ensuring that
programmers have access only to the
interface part. In this way encapsulation
provides a form logical data
independence: we can chance the internal
implementation of an ADT without
changing any of the application using that
ADT
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Methods
• In object technology, function are usually
called methods.
• Methods define the behavior of the object.
They can used to change the object state
by modifying its attribute values, or to
query the values selected attributes
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Message
• Message are the means by which objects
communicate.
• A message is simply a request from one
object to another object asking the second
object to execute one of its methods.
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Inheritance
• Inheritance allows one class to be define a
special case of a more general class.
• This special case are known as subclass
and more general class are known as
superclass.
• The process of forming a superclass is
referred to as generalization and process
of forming a subclass is specialization
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Polymorphism
• The word of Polymorphism come from
Greek meaning ' having many forms‘.
• Conducive Polymorphism a method which
have been defined at superclass earn redefinition at subclass according to what
becoming requirement of subclass.
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Dynamic binding
• Therefore in technology object-oriented
needed a mechanism arranging how a
method executed.
• This mechanism is referred as binding.
• Dynamic Binding is a mechanism election
of correct method to be executed at the
time of runtime.
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SUMMARY
• Object Oriented Concepts include :
– Abstraction
– Encapsulation
– Information hiding
– Methods
– Message
– Inheritance
– Polymorphism
– Dynamic binding
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