A framework for defining XML views

XML has become the de facto standard for representing and interchanging data in web-based applications. And XML view has been widely applied. In relational database, the views are often defined by a query statement, though there may be GUI tools as aids. However, the users usually desire a conceptual modeling tool to help them define views and communicate with each other. Richer semantics are also expected when users tackle view related issues, such as view updates. In this paper, we present a framework for defining XML views, which includes three levels: conceptual level, logical level and physical level. Conceptual level is described by some conceptual model, e.g. EER or UML. Logical level is captured by some XML schema language and physical level is the XML views data. In particular, we show what semantics should be captured and how to represent them.