5.4.4. Multiplicity Constant
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5.4.4. Multiplicity Constant

[Tip]Description

A multiplicity constant is used to specify multiplicity restrictions for a relation.

[Important]Syntax
MultiplicityConstantAST ::= one_to_one | one_to_many 
	                        | many_to_one | many_to_many

The possible values of a multiplicity constant are one_to_one, one_to_many, many_to_one and many_to_many.

[Note]Semantics

Both end of a relation can have either the multiplicity oneor the multiplicity many. In the model space only a single property determines the multiplicity of a relation that holds the multiplicity information for both ends.

The interpretation of multiplicity kinds in VPM are

  • one_to_one: for each source element at most one target element can be in relation, and for each target element at most one source element can be in relation for each instance of the relation,

  • one_to_many: for each target element at most one source element can be in relation each instance of the relation,

  • many_to_one: for each source element at most one target element can be in relation for each instance of the relation

  • many_to_many: an arbitrary number of source and target elements can be in relation.

The default value of a multiplicity is many_to_many.

Defined In:  ASM constant

Used By:  element update rule (setMultiplicity), predefined function call ( multiplicity)

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