In this paper we present a uniform approach to dynamic relationships in object oriented databases. We present our relationship categorisation based on dividing the object database into three virtual spaces each hosting entities of a particular type and show how relationships from the modelling domain map onto relationships in our categorisation. We present a relationship model and the semantics of relationships. The relationship model is complemented with a metamodel for implementing dynamic relationships in an object oriented database. The applicability of the dynamic relationships approach is explored by employing it to implement the database model for a system in order to achieve dynamic schema modification capabilities.