Toward Better Logical Models in UML

In this paper we present that the logical models in UML can be made better in three ways. Firstly these can avoid the limited ways of using UML to overcome two deficiencies: i. the ambiguous interpretation of classes, and ii. a lack of one to one correspondence with the textual representations of the models. Secondly the models can be hierarchical based on the notions of entity, collection, relation, and control classes. The collection, and relation classes are for overcoming the first two deficiencies mentioned above. Thirdly relation driven design can be used as an alternative to behaviour driven design, which is clumsy and leads to spaghetti logical models. The latter views computation as interactions of objects and is very widely used in UML based design methods. Relation driven design is a novel contribution of this paper. On the contrary it is based on an alternate view of computation as interactions of relations rather than objects. Hierarchical logical models resulting from relation driven design are easier to understand, and maintain than the spaghetti ones resulting from behaviour driven design.