Relation - Zistack/program-modeling-language GitHub Wiki

A relation is an abstract kind of object. There are many specific kinds of relations which have specific syntax and definitions.

However, all relations share some terminology.

Like variables, relations have instances. A single instance of a relation generally corresponds to a single instance of each of the relation's related variables, though there are some exceptions.

Each instance contains records with fields whose names are dictated by the definition of the relation. These records assign elements of the related variables to their fields. The combinations of element to field assignments which are present are defined according to the kind of relation.