Thesis full text (PDF) - Politecnico di Milano

consists of a data schema, describing application data, and of one or more hypertexts (called site
views), expressing the Web interface used to publish and manipulate such data.
The specification of a WebML application consists of a set of models: the application data model
(an extended Entity-Relationship or UML Class Diagram), one or more hypertext models (i.e.,
different site views for different types of users), describing the Web application structure; the
presentation model, describing the visual aspects. The hypertext main concept is the site view,
which is a graph of pages; pages are composed by units, representing publishing of atomic pieces
of information, and operations for modifying data or performing arbitrary business actions. Units
are connected by links, to allow navigation, parameter passing, and computation of the hypertext.
We do not exploit MDA entirely but we inspired and do some transformation from WebML
where WebML assures MDA.
2.2 Web Modeling Language (WebML)
Web Modeling Language (WebML) is a methodology for specifying complex web application
design at the conceptual level. WebML guarantees a model driven architecture (MDA) approach
for developing web application. This is a key factor for defining a novel generation of CASE tool
for the construction of complex sites and for supporting advanced features like personalization,
evolution and multi device access. It enables the high level description of a web application
under distinct orthogonal dimensions – structural model (the data content), composition model
(the pages that compose it), navigation model (links between the model), presentation model (the
layout and graphic requirements for page rendering), and personalization model (customized
features of the contents). WebML consists a set of visual graphic notation to represent all the
components for defining the conceptual schemas and to represent the hypertext interface. The
WebML primitives are also provided with an XML-based (XMI format) textual representation
for specifying the data underlying the application. WebML exploits the ER (Entity Relationship)
model which consists of entities defined as containers of data elements and relationships defined
as semantic connections between entities.
The specification of a site in WebML consists mainly four orthogonal perspectives:
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