Page 137 - DCAP308_OBJECT_ORIENTED_ANALYSIS_AND_DESIGN

Unit 11: Domain Analysis

11.1.4 Finding Association Notes

Reference from one class to another

Example: Class person and company relate them with Works for.
Means verbs or phrases – physical phrase (next to, part of, contained), directed action ,
communication (talks to ), ownerships (has, part of ),some condition (works for, manages)

11.1.5 Criteria for Keeping Right Association

Association between Eliminated Classes

If you eliminate one class in association, you must eliminate association

Example: Eliminate Banking network includes cashier station and ATMs

Irrelevant /Implementation Association

Outside the problem domain or deals with implementation constructs

Example: System handles concurrent access is implementation concept.

Actions

Association describe structural property, not an event for object

Example: ATM accepts card describes part of interaction between ATM & customer not a
permanent relationship between them.

Ternary Association

Decompose most association among three or more classes into binary association.

Example: Bank computer processes transaction against account can be broken into:
Bank computer processes transaction

Transaction concerns account
Derived Association

Omit association that can be defined in terms of other association because they are
redundant

Example: Grandparent of can be defined in terms of pair of Parents of.
Classes, attributes and associations in class model represent independent information.

Multiple paths between classes indicates derived association

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