Esperanza Marcos

A methodological approach for object-relational database design using UML

Abstract.The most common way of designing databases is by means of a conceptual model, such as E/R, without taking into account other views of the system. New object-oriented design languages, such as UML (Unified Modelling Language), allow the whole system, including the database schema, to be modelled in a uniform way. Moreover, as UML is an extendable language, it allows for any necessary introduction of new stereotypes for specific applications. Proposals exist to extend UML with stereotypes for database design but, unfortunately, they are focused on relational databases. However, new applications require complex objects to be represented in complex relationships, object-relational databases being more appropriate for these requirements. The framework of this paper is an Object-Relational Database Design Methodology, which defines new UML stereotypes for Object-Relational Database Design and proposes some guidelines to translate a UML conceptual schema into an object-relational schema. The guidelines are based on the SQL: 1999 object-relational model and on Oracle8i as a product example.

Applying CIM-to-PIM model transformations for the service-oriented development of information systems

Context: Model-driven approaches deal with the provision of models, transformations between them and code generators to address software development. This approach has the advantage of defining a conceptual structure, where the models used by business managers and analysts can be mapped into more detailed models used by software developers. This alignment between high-level business specifications and the lower-level information technologies (ITs) models is crucial to the field of service-oriented development, where meaningful business services and process specifications are those relevant to real business scenarios. Objective: This paper presents a model-driven approach which, starting from high-level computational-independent business models (CIMs) - the business view - sets out guidelines for obtaining lower-level platform-independent behavioural models (PIMs) - the information system view. A key advantage of our approach is the use of real high-level business models, not just requirements models, which, by means of model transformations, helps software developers to make the most of the business knowledge for specifying and developing business services. Method: This proposal is framed in a method for service-oriented development of information systems whose main characteristic is the use of services as first-class objects. The method follows an MDA-based approach, proposing a set of models at different levels of abstraction and model transformations to connect them. Results: The paper present the complete set of CIM and PIM metamodels and the specification of the mappings between them, which clear advantage is the support for the alignment between high-level business view and ITs. The proposed model-driven process is being implemented in an MDA tool. A first prototype has been used to develop a travel agency case study that illustrates the proposal. Conclusion: This study shows how a model-driven approach helps to solve the alignment problem between the business view and the information system view that arises when adopting service-oriented approaches for software development.

WSDL automatic generation from UML models in a MDA framework

In this work, we introduce the MIDAS-CASE subsystem for Web services. MIDAS-CASE is a MDA tool for Web information systems development. Using an extension of UML language for representing the Web services Description Language standard, the MIDAS-CASE subsystem proposed supports the modeling of Web services in extended UML and the automatic generation of the respective WSDL description for the Web service modeled.

TOWARDS A SERVICE-ORIENTED MDA-BASED APPROACH TO THE ALIGNMENT OF BUSINESS PROCESSES WITH IT SYSTEMS: FROM THE BUSINESS MODEL TO A WEB SERVICE COMPOSITION MODEL

In recent years, the automation of business processes has become one of the most prominent and promising uses of Web service technology. Consequently several languages have been created for the execution of business processes, making it possible to define new and more complex services or business processes which are implemented for example by means of Web service composition. Nevertheless, these kinds of languages are not suitable for use in the early stages of the development process of information systems. Special methodologies or techniques are therefore necessary to allow systems analysts to understand services from a business point of view, while facilitating the design and development of Web service composition. In this paper, we present a service-oriented approach to information system development that starts by identifying, through business modeling, the services required by the customers of a business, to make it possible to create a Web service composition model. This model will facilitate the transformation to specific languages for business process execution, thereby reducing the development efforts made in service-oriented applications. The method proposed is illustrated by means of a Web application for the management of medical images, which we have taken as a case study.

A model driven method for service composition modelling: a case study

In recent years, innovation in technologies such as XML, web services and component-based development has led to interest in business processes. For this reason several languages for designing and implementing business processes, such as Business Process Execution Language for Web Services (BPEL4WS), have been created. However, one weakness of these languages is that they are difficult for business analysts to use in the early stages of the web information systems development process. In this work, we present a model-driven method for service composition modelling. The method defines a process, new models and the mappings between them. The process first identifies the services that will be offered to the user and then allows obtaining a service composition model, which facilitates the mapping to a specific web services composition language. The proposed method is illustrated through a case study of a web information system for the management of medical images.

Modelling of Service-Oriented Architectures with UML

Nowadays, service-oriented architectures are becoming gradually more important. The vast diversity of implementation and support platforms for this kind of architectures (such as Web, Grid or even CORBA) increases the complexity of the development process of service-based systems. With the aim of facilitating the development of service oriented solutions, we propose the specification of an architecture centric model driven development method. To achieve this, we study the architectural properties of the SOA paradigm and follow a development approach based on the MDA proposal. MDA proposes a separation of the development process in abstraction levels. This makes MDA suitable to tackle the development of service-oriented systems. This paper describes a UML profile for the PIM-level service-oriented architectural modelling, as well as its corresponding metamodel. PIM (Platform Independent Model) level is chosen because it does not reflect constraints about any specific platform or implementation technology. To exemplify and validate the profile, a case study is presented in which the proposed profile is used.

Modeling semantic web services: a case study

Nowadays, there is an enormous amount of study about the semantic Web, especially regarding one specific technology: semantic Web services. However, to be widely adopted by users and to succeed in real-world applications, semantic Web services development must catch up with mainstream software trends. As has already occurred with traditional Web services, Web development should be adapted to support the systematic development of the new components required by applications involving semantic Web services. In this paper we present, through a case study, an approach for developing semantic Web services. This approach is based on the extension of MIDAS, a model-driven methodology for Web Information Systems development.

Representing Web Services with UML: A Case Study

Nowadays services are one of the most important issues in the scope of the Web Information Systems (WIS). Although, there is a great amount of Web services, still it do not exist methods or modelling techniques that can guarantee quality in services and service-oriented applications development. MIDAS is a model-driven methodology for the development of WISs and is based on UML, XML and object-relational technology. Web services represent a new dimension in WIS development, in which the systems are constructed by means of transparent integration of services available in the Web. WSDL is the language proposed by the W3C for Web service description. In this paper, an UML extension for Web services modelling defined in WSDL is described through a case study.

Extending UML for Object-Relational Database Design

The most common way of designing databases is using de E/R model without taking into account other views of the system. However, new object-oriented design languages, such as UML (Unified Modelling Language), permit modelling the full system, including the database schema, in a uniform way. Besides, as UML is an extensible language, it allows introducing new stereotypes for specific applications if it is needed. There are some proposals to extend UML with stereotypes for database design but, unfortunately, they are focused on relational databases. However, new applications require representing complex objects related with complex relationships and object-relational databases are more appropriated to support the new application requirements. The framework of this paper is an Object-Relational Database Design Methodology. The methodology defines new UML stereotypes for Object-Relational Database Design and proposes some guidelines to translate an UML schema into an object-relational one. The guidelines are based on the SQL:1999 object-relational model and on Oracle8i as an example of product. In this paper we focus on the UML extensions required for object-relational database design.

Applying MDE to the (semi-)automatic development of model transformations

ContextModel transformations play a key role in any software development project based on Model-Driven Engineering principles. However, despite the inherent complexity of developing model transformations, little attention has been paid to the application of MDE principles to the development of model transformations. ObjectiveIn order to: (a) address the inherent complexity of model transformation development and (b) alleviate the problem of the diversity of the languages that are available for model transformation, this paper proposes the application of MDE principles to the development of model transformations. In particular, we have adopted the idea of handling model transformations as transformation models in order to be able to model, transform and generate model transformations. MethodThe proposal follows an MDA-based approach that entails the modeling of model transformations at different abstraction levels and the connection of these models by means of model transformations. It has been empirically validated by conducting a set of case studies following a systematic research methodology. ResultsThe proposal was supported by the introduction of MeTAGeM, a methodological and technical framework for the model-driven development of model transformations that bundles a set of Domain-Specific Languages for modeling model transformations with a set of model transformations in order to bridge these languages and (semi-)automate model transformations development. ConclusionThis paper serves to show that a semi-automatic development process for model transformations is not only desirable but feasible. This process, based on MDE principles, helps to ease the task of developing model transformations and to alleviate interoperability issues between model transformation languages.