1. childOf Children motherOf parentOf Persons Mother fatherOf
childOfMother
childOfFather
class Person {
attribute string name;
relationship Person motherOf inverse Person::childOfMother;
relationship Person childOfMother inverse Person::motherOf;
relationship Person fatherOf inverse Person::childOfFather;
relationship Person childOfFather inverse Person::fatherOf;
relationship Person parentOf inverse Person::childOf;
relationship Person childOf inverse Person::parentOf; }
The reason for the six relationships: when we have a relationship R between C and D, the ODL
declaration for C and D – each will contain one relationship describing the role of R with respect to C
and D. In this case, C and D are “Person” – thus, for each relationship we need two in the class
definition.
Looking at relationship with roles (even when the C is different from D) makes it easier to specify the
constraints.