1 Pertemuan 9 The Manipulative part of the object data model Matakuliah: M0174/OBJECT ORIENTED DATABASE Tahun: 2005 Versi: 1/0

2 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)

3 Outline Materi What is an object algebra ? The Object algebra –Expression –Operators

4 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

5 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.

6 The Object algebra Example Retail_Customer Union [Customer] Set(Customer(Customer_no:’C2’, name:’Barry’))

7 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.

8 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.

9 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.

10 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

11 The Object algebra Operation which define objects that are of interest: –Restrict –Union –Intersect –Difference –Choose –Duplicate-Elimination –Group

12 The Object algebra Operator which apply operations to objects of interest: –Apply –Fold –Join –Tuple-Join –Outer-Join –Least-Fixed-Point

13 The Object algebra Control Operators –Exists –Forall –Member Operator for restructuring objects –Set –Beg –Nest –Unnest –Convert

14 SUMMARY Object algebra is object, what conventional algebra is numbers expressions define objects by applying operators to other objects represent by constants and variables