Add Association Class to Composition relationship

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I'd like to know if it is correct to add an Association Class to a Composition relationship?

For example (see figure below), can I add an Association Class (i.e. NameValue class) to the composition relationship between Name class and Value class? One Name can have multiple Value and one Value can only be attached to one Name. NameValue class stores the name-value pairs.

The reason why I create the association class (i.e. NameValue class) is that I need to create associations/relationships between NameValue class and other classes such as Class A.

If the answer is yes, is it recommended to turn the association class into a normal class?

enter image description here

Many thanks!

uml
1 Answers

I'd like to know if it is correct to add an Association Class to a Composition relationship?

yes in an association-class the association can have an owner-end property being a composition, in formal/2017-12-05 there is nothing in § 11.5.3.2 Association Classes starting page 200 nor in § 11.8.2 AssociationClass [Class] against that even association-class has some constraints

NameValue class stores the name-value pairs.

note this is absolutely not the goal of the class of an association-class in UML, and not necessary the case when you implement an association-class

The reason why I create the association class (i.e. NameValue class) is that I need to create associations/relationships between NameValue class and other classes such as Class A

because NameValue is used at implementation level to stores the name-value pairs and then to implement the association(-class), in UML the diagram you want is :

enter image description here

(NameValue does not exist at UML level but only at implementation level)

If the answer is yes, is it recommended to turn the association class into a normal class?

At UML level the association-class do not exist for nothing, they make the model clear, so I do not recommend to not use class-association (but this is of course opinion-based)

user_24589910
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