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UML - reading for the empty diamond and solid diamond arrows

Posted on 2004-09-28
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What is the "reading" of those arrows with diamonds on the end?

For empty diamond, A <>-----> B is it "A can contain B" or "B can be a part of A"?
                                   
And for solid diamond A<->-----> B is it "A must contain B" or "B is a (necessary) component of A"?

I'm having trouble with the difference between solid and clear diamond. So if I could get the readings for these symbols, it would be helpful.

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Question by:rfr1tz
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by:gdrnec
ID: 12173921
Composition and Aggregation
Composition is a special type of aggregation that denotes a strong ownership between Class A, the whole, and Class B, its part. Illustrate composition with a filled diamond.
Use a hollow diamond to represent a simple aggregation relationship, in which the "whole" class plays a more important role than the "part" class, but the two classes are not dependent on each other. The diamond end in both a composition and aggregation relationship points toward the "whole" class or the aggregate.
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Jaime Olivares earned 1000 total points
ID: 12174015
I like to use these simple terms:
When diamond is filled, the pointed object is a part of the pointing object as a leg is to a person
When diamong is empty, the pointed object is related but not a part of pointed object as a shoe to a person
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