Ordinal Hop - modelint/shlaer-mellor-metamodel GitHub Wiki

An Ordinal Hop is just like an Asymmetric Circular Hop since it also has two Perspectives.

images/ordinal-hop-10.png

OR6 is formalized by the Height and Tower stack attributes. Increasing values of Height are unique within a Tower Stack (separate vertical unit of a Building).

Instead of using referential attributes, an Ordinal Relationship uses a relational operation that selects all floors higher than a given floor and then chooses the lowest value in that subset to obtain the next highest floor.

Traversal in one direction or the other requires the relationship name (Rnum) and either the next ascending or descending value as indicated by the Perspective.

This traversal can be expressed in Scrall like so:

next highest floor .= my floor/OR6/higher

Identifiers

1. Number + Path + Domain

Attributes

Ascending

This indicates the direction of the hop. Instances are ordered by a ranked value and one perspective is associated with the ascending direction while the other is associated with the descending direction. If the value of this attribute is true, the hop is toward the ascending perspective.

Type

Boolean