Transcript Pertemuan 9 The Manipulative part of the object data model Matakuliah

Matakuliah
Tahun
Versi
: M0174/OBJECT ORIENTED DATABASE
: 2005
: 1/0
Pertemuan 9
The Manipulative part of the object
data model
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Mahasiswa dapat Menjelaskan proses
manipulasi object data model dan
operator-operator yang digunakan dalam
manipulasi tersebut (C2)
2
Outline Materi
• What is an object algebra ?
• The Object algebra
– Expression
– Operators
3
What is an object algebra ?
• An Object Algebra is define as a set of
object database language which can be
used to implement actual object database
system.
• These are ODL, OQL and the object
definition and manipulative language
extension to programming language e.g
Java, C++, Smaltalk
4
The Object algebra
• Algebra Expression
– object algebra is similar like conventional
algebra. the expression in object algebra also
constructed from variables, constant and
operator, but instead of the number, their
value are objects.
5
The Object algebra
• Example
Retail_Customer
Union [Customer]
Set(Customer(Customer_no:’C2’,
name:’Barry’))
6
The Object algebra
• An object database for an organization will
contain objects which represent entities of
interest to an organization.
• Each application may require access to
information about some of those entities
and so must access and process some of
the objects.
7
The Object algebra
• Other applications must modify the object
database, by creating or deleting objects
and by modifying the state of existing
object, so as to reflect changes to the
world in which the organization operates.
8
The Object algebra
• In order for object algebra to describe
such applications, it must be able to
express the following three general
operations:
– Definition of the objects that are of interest
– Application of operations to objects of interest
– Return of an object which represents the
required information.
9
The Object algebra
• Object Algebra Operators
– Object algebra operators can be divided into
four groups:
• Operation which define objects that are of interest.
• Operator which apply operations to objects of
interest.
• Control Operator
• Operator for restructuring objects
10
The Object algebra
• Operation which define objects that are of
interest:
– Restrict
– Union
– Intersect
– Difference
– Choose
– Duplicate-Elimination
– Group
11
The Object algebra
• Operator which apply operations to objects
of interest:
– Apply
– Fold
– Join
– Tuple-Join
– Outer-Join
– Least-Fixed-Point
12
The Object algebra
• Control Operators
– Exists
– Forall
– Member
• Operator for restructuring objects
– Set
– Beg
– Nest
– Unnest
– Convert
13
SUMMARY
• Object algebra is object, what
conventional algebra is numbers
expressions define objects by applying
operators to other objects represent by
constants and variables
14