Research On XML Modeling Tools Based On Conceptual Model

The XML schema is used to describe the structure and constraints of an XML instance document,in order to verify the validity of the instance document.With the widespread use of XML and the dramatic increase in the number of XML documents,the design of XML schemas(XML design for short)becomes more and more important.XML design involves two elements:The first one is knowledge in the field of application.Designers need to understand the relationship between related concepts and concepts in the application domain.The other one is XML Schema definition language(such as W3 C XML Schema Definition Language),designers need to be skilled in writing an XML schema by using a schema definition language which can define concepts and relationships in the application domain accurately.It can be concluded that XML design is such a complex task that requires appropriate design methods and design tools to assist.XML design is similar to relational database design.In an actual database design project,an auxiliary design tool such as PowerDesigner can be used to design the conceptual model firstly,and then the tool can generate both the database logic model and the DBMS-related implementation mode(SQL code)automatically.During the process,the focus of the database design is conceptual modeling,designers do not even need to understand the syntax details of the SQL language.The "Model-Driven Architecture" concept advocated by OMG in recent years has already become a reality in the field of database design.By analyzing the current status of XML design and the successful experience of database design,we realized that the core of XML design is conceptual model and conceptual modeling.Therefore,we mainly research the XML design methods and design tools based on conceptual model in this thesis.We use a new meta-modeling tool(MetaEdit+)to develop the XML design tool.The main contents of the thesis are as follows:(1)Defining the XML conceptual modeling language of XUML model with GOPPRR.XUML,a conceptual model based on UML class diagrams,is propitious to describe XML conceptual models.For people who are familiar with class diagrams,XUML is easy to master.GOPPRR is a meta-modeling language embedded in MetaEdit+.This thesis defines the modeling elements,connection rules and integrity constraints in XUML by using GOPPRR.(2)Designing transformation algorithms from XUML conceptual model to XML Schema.By analyzing the correspondence between the XUML conceptual model and XML Schema,the mapping rules between the two models are defined at the metamodel level;based on these mapping rules mentioned above,the transformation algorithms from XUML conceptual model to XML Schema are designed by using the generator definition language MERL in MetaEdit+.(3)Designing and implementing a set of tools that support the aforementioned XUML concept modeling and model transformation.The tool has two core functions.First,it supports the XML conceptual modeling language XUML which can help designers create an XML conceptual model.Second,it implements the above transformation algorithms and can support the automatic conversion from the XUML concept model to the XML Schema.With the help of this tool,the designers of the XML schema will focus on XML conceptual modeling and may not understand the syntax details of the XML schema definition language.The model transformation tool can then transform the XML conceptual model into a syntactically correct XML schema automatically or semi-automatically.Therefore,this tool is proved to simplify XML schema design and improve the efficiency of XML schema design.