First class relationships for oo languages

Abstract. Relationships have been an essential component of OO de-sign since the 90s and, although several groups have attempted to rectify this, mainstream OO languages still do not support first-class relation-ships. This requires programmers to implement relationships in an ad-hoc fashion which results in unnecessarily complex code. We have developed a new model for OO languages which presents relationships as the domi-nant mechanism for defining object-oriented behaviour. We believe that a language based on this model could bring the benefits of relationships to mainstream languages and allow better integration between OO systems and other paradigms such as relational databases.