1

Pertemuan 8The Object Definition Language (Lanjutan)

Matakuliah : M0174/OBJECT ORIENTED DATABASE

Tahun : 2005

Versi : 1/0

2

Learning Outcomes

Pada akhir pertemuan ini, diharapkan mahasiswa

akan mampu :

• Mahasiswa dapat Menjelaskan object definition language lanjutan (C2)

• Mahasiswa dapat Menjelaskan hubungan antara ODL dengan bahasa program dan database schema (C2)

3

Outline Materi

• A class or interface body • Attributes • Relationships • Operations • Constants• Type declarations • Exceptions• Modules • ODL in a distributed environment

4

A class or interface body

• Definition

• The general form of the body of an object type definition

• In addition, characteristic declaration can define the types, constants, and exceptions used in the other characteristic declarations

5

Attributes

• Attributes can be thought of as the values that an object contains

• Examples

6

Relationships

• Definition

• Each relationship declaration must state :– The name of the path from instances to

associated objects– The type of the associated objects– And optionally, the name of the inverse path,

from the associated objects back to the instances

7

Operations

• Definition

• An operation declaration must specify :– The operation name– The type of the object it returns when

executed– The type of each the objects that it accepts as

a parameter– Exceptions that may be raised by the

operation

8

Constants

• As in programming language, it is often useful to give constants meaningful names which they can be reffered to.

• Examples

9

Type declarations

• Type generators can be used to create new types

• Examples

10

Exceptions

• Exceptions are objects which represent exceptional events

• Examples

11

Modules

• Parts of a schema can be packaged together to form named modules

• Examples

12

ODL in a distributed environment

• In a distributed environment objects may be implemented on different computers using different languages

• Examples

13

SUMMARY

• A set of declarations defined in ODL is schema

• An ODL schema contains a set of interface and class definitions for object type in a object database

• A schema may also include type, constant, and exception declaration.

• Declaration can be combined to from named modules