03-08-2012, 01:37 PM
Transformation of UML Class Diagram for Object Oriented Database System
ABSTRACT
Now-a-days use of objects is a common approach in all aspects
of computing. An Object-Oriented database can utilize the
benefits of both the design and implementation of any
application. Object-Oriented database System is the fusion of
Database Management System with Object-Oriented System.
UML provides stable and industry standard notation for objectoriented
analysis and design models. A case study of NSC
scheme of Indian Postal Services is considered for storing the
data using object database modeling. UML class diagram and
sequence diagram are constructed for the post office system and
then the transformation of class diagram is done for the ease of
understanding and working.
INTRODUCTION
The benefits of employing object technology in application
design and development are now well known. Viewing real life
problems in terms of objects can often lead to a more natural
design and thus a better implementation [1]. Many recent
research efforts have been devoted to the definition of objectoriented
database models. These are data models based on the
notions of object, class, attribute, and method, where classes and
attributes are used to describe the structural aspects of object and
methods are used to represent their dynamic aspects [2]. UML is
a language to specify, construct, present and document artifacts
of both software systems and business processes and other
systems that are not strictly software [3]. Object-oriented
software development has been in wide use for some time.
There is now a stable, industry-standard notation for objectoriented
analysis and design models – the Unified Modeling
Language (UML) [4], [5].
THE UML CLASS DIAGRAM
In recent years, the Unified Modelling Language (UML) has
emerged as the defacto standard for the representation of
software engineering diagrams (Rumbaugh et al.1999) [5]. The
UML class diagram contains classes, interfaces, collaborations,
and dependencies, associations and interface relationships [6].
The UML class diagrams are used to describe the static view of
any application. Classes and their relationships are the main
constituents of class diagram. A class is a description of a
concept which may have attributes and operations associated
with it. Classes are represented as rectangles and relationship
between two classes is drawn as a line.
TRANSFORMATION PROCESS
UML is very complex modeling language. The objective of
transformation is to explain more complex features in terms of
basic ones. Its static modeling with class diagram involves many
description primitives such as qualifiers, cardinality constraints,
association classes, compositions, aggregations and
generalizations. The n-ary associations and OCL constraints are
used for the transformation process.
The Object Constraint Language (OCL)
Instructions for specifying constraints and actions in any model.
A constraint is a restriction on an element that limits the usage
of that particular element. The OCL is a notational and formal
mathematical expression language. When we view entire
modeling details and relationship of any class diagram it appears
complex but by using OCL, the complexity can be reduced.
Relationships in class diagram are removed after they have been
defined by the OCL expressions [6].
CONCLUSION AND FUTURE WORK
UML diagrams are designed for an OODBMS and here we have
presented an approach to transform the existing UML class
diagram into equivalent class diagram. Our results suggest that
some of the UML class diagram concepts increases the
complexity and works as a shortcut for existing one. We have
translated few UML features such as qualifiers, association
classes, compositions and generalizations into association
relations with additional constraints because the association
concept is a very general and it is able to model many situations.