A conceptual schema for a conference management application

Conference management applications have been widely used as examples for the study of conceptual schemas because of their manageable size and diversity of cases. However, as far as we are concerned, the conceptual schemas available only refer to the structural or static part of these systems. Therefore we have considered useful and necessary for our work to develop a whole specification, including the behaviour of a conference management application. The conceptual schema proposed in this paper is based on the study of the code of a real existing product: MYREVIEW. Additionally, this paper has also permitted to test or consolidate the real application of some proposals. The first group consists on alternate mechanisms to define integrity constraints and derived elements proposed by Olivé. The root of these proposals is the definition of constraint and derived elements by means of operations. Secondly, it aims at exploiting the benefits of modelling events as entity types proposed by Olivé. Finally, it also includes the distinction between domain events, action request events and query events in which Olivé and Raventós are currently working.Postprint (published version

Validation of UML conceptual schemas with OCL constraints and operations

Per tal de garantir la qualitat final d'un sistema d'informació, és imprescindible que l'esquema conceptual que representa el coneixement sobre el seu domini i les funcions que ha de realitzar sigui semànticament correcte.La correctesa d'un esquema conceptual es pot veure des de dues perspectives. Per una banda, des del punt de vista de la seva definició, determinar la correctesa d'un esquema conceptual consisteix en respondre la pregunta "És correcte l'esquema conceptual?". Aquesta pregunta es pot respondre determinant si l'esquema satisfà certes propietats, com satisfactibilitat, no redundància o executabilitat de les seves operacions.D'altra banda, des de la perspectiva dels requisits que el sistema d'informació ha de satisfer, l'esquema conceptual no només ha de ser correcte sinó que també ha de ser el correcte. Per tal d'assegurar-ho, el dissenyador necessita algun tipus de guia i ajut durant el procés de validació, de manera que pugui entendre què està representant l'esquema exactament i veure si es correspon amb els requisits que s'han de formalitzar.En aquesta tesi presentem una aproximació que millora els resultats de les propostes anteriors adreçades a validar un esquema conceptual en UML, amb les restriccions i operacions formalitzades en OCL. La nostra aproximació permet validar un esquema conceptual tant des del punt de vista de la seva definició com de la seva correspondència amb els requisits.La validació es porta a terme mitjançant un conjunt de proves que s'apliquen a l'esquema, algunes de les quals es generen automàticament mentre que d'altres són definides ad-hoc pel dissenyador. Totes les proves estan formalitzades de tal manera que es poden tractar d'una manera uniforme,independentment de la propietat específica que determinen.La nostra proposta es pot aplicar tant a un esquema conceptual complet com només a la seva part estructural. Quan es pretén validar només la part estructural d'un esquema, oferim un conjunt de condicions que permeten determinar si qualsevol prova de validació que es pugui fer sobrel'esquema acabarà en temps finit. Per aquells casos en els quals aquestes condicions de terminació se satisfan, també proposem un procediment de raonament sobre l'esquema que s'aprofita d'aquest fet i és més eficient que en el cas general. Aquesta aproximació permet validar esquemes conceptuals molt expressius, assegurant completesa i decidibilitat al mateix temps.Per provar la factibilitat de la nostra aproximació, hem implementat el procés de validació complet per a la part estructural d'un esquema. A més, per a la validació d'un esquema conceptual que inclou la definició del comportament, hem implementat el procediment de raonament estenent un mètode existent.To ensure the quality of an information system, it is essential that the conceptual schema that represents the knowledge about its domain and the functions it has to perform is semantically correct.The correctness of a conceptual schema can be seen from two different perspectives. On the one hand, from the point of view of its definition, determining the correctness of a conceptual schema consists in answering to the question "Is the conceptual schema right?". This can be achieved by determining whether the schema fulfills certain properties, such as satisfiability, non-redundancy or operation executability.On the other hand, from the perspective of the requirements that the information system should satisfy, not only the conceptual schema must be right, but it also must be the right one. To ensure this, the designer must be provided with some kind of help and guidance during the validation process, so that he is able to understand the exact meaning of the schema and see whether it corresponds to the requirements to be formalized.In this thesis we provide an approach which improves the results of previous proposals that address the validation of a UML conceptual schema, with its constraints and operations formalized in OCL. Our approach allows to validate the conceptual schema both from the point of view of its definition and of its correspondence to the requirements.The validation is performed by means of a set of tests that are applied to the schema, including automatically generated tests and ad-hoc tests defined by the designer. All the validation tests are formalized in such a way that they can be treated uniformly, regardless the specific property they allow to test.Our approach can be either applied to a complete conceptual schema or only to its structural part. In case that only the structural part is validated, we provide a set of conditions to determine whether any validation test performed on the schema will terminate. For those cases in which these conditions of termination are satisfied, we also provide a reasoning procedure that takes advantage of this situation and works more efficiently than in the general case. This approach allows the validation of very expressive schemas and ensures completeness and decidability at the same time. To show the feasibility of our approach, we have implemented the complete validation process for the structural part of a conceptual schema.Additionally, for the validation of a conceptual schema with a behavioral part, the reasoning procedure has been implemented as an extension of an existing method