R104 - modelint/shlaer-mellor-metamodel GitHub Wiki

R104 / 1:Mc

Ordinal Relationship ranks instances by value in exactly one Class

Class has instances ranked in value by zero, one or many Ordinal Relationship

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An Ordinal Relationship may be defined on a Class to order that Class's instances using the value of one of that Class's Identifier Attributes.

A given Class may or may not have its instances ordered in this manner. In fact, the instances may be ordered in more than one way by employing multiple Ordinal Relationships, each with its own distinct ranking Identifier Attribute, see R106.

Erik Söderholm has pointed out that the logic of this relationship, R104, is derivable from R106.

Formalization

Ordinal Relationship.(Ranked class, Domain) -> Class.(Name, Domain)