A semi-structured object model with relations

This paper introduces a semi-structured object model based on a weak notion of object classes, named categories. In our model, a category holds common properties of a set of objects. An object in our model may have features of its own, not abstracted in the category to which they belong; hence the semi-structured nature of the model. This feature of the model is very useful in domains where object structures can not be easily abstracted in classes. Besides, object structures in our model are based on object components and internal relationships between them. Relationships are only used to enrich the description of objects, by specifying links between their components, thus, they are properties of the main object and not of those components. This approach makes it possible to represent contextual relationships (that are valid only in the context of the main object). It also insures information localization (within the main object) which is an important feature of object orientation. A suited query language has been defined. Queries are specified in the same way as objects