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Aggregation in Class Diagram

Chih-Wei Lee
Ranch Hand

Joined: Feb 20, 2008
Posts: 129
Hi All:
I just started working on the class diagram for Dreamcar assignment.
Is there any Aggregation relationship among the entities from BDM?
I have searched the definition of Aggregation - There is a "whole-part" relationship between two objects.
For example, an enterprise contains employees.
But I didn't see any Aggregation relationship among the entities from Dreamcar BDM.
Do I miss something?
How do you guys think about this?

Best,

Chris


SCEA, SCJD, SCDJWS, SCWCD, SCJP
J J Wright
Ranch Hand

Joined: Jul 02, 2008
Posts: 254
A Business Domain Model, as the name suggests, describes how a business functions. Your class diagram,.as part of the Design Model, describes the software implementation. The Business Architect, or whoever else produced the Business Domain Model, probably doesn't care about the exact semantics of the business-employee relationship, so they left it off their diagram.


SCJP, SCWCD, SCBCD, SCEA 5
Chih-Wei Lee
Ranch Hand

Joined: Feb 20, 2008
Posts: 129
After rethinking the BDM, I have found there should be a aggregation relationship between CarModel and Brake Discs, Brake Pads and Suspension. Moreover, the multiplicity between CarModel and these parts is Many-to-Many, which means one type of brake discs can be placed on multiple car model and a car model can have different type of brake discs (front and rare).
It turns out my CarModel has a list of Brake Discs, Brake Pads and Suspension respectively.
The problem with this design is if there is new part added to system, I will need to add another attribute on CarModel class.
How do you guys design the relationship between CarModel and Brake Discs, Brake Pads and Suspension?

Best,

Chris
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Aggregation in Class Diagram
 
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