1. A system for managing XML schema in XML-based software, the XML schema comprising XML schema fragments regarding an XML-based computer environment, the system comprising: a computer configured to provide: a repository configured to store a manipulatable object model of the XML schema fragments, the object model: (a) comprising a plurality of objects, each object having a version, and (b) representing metadata about the XML schema fragments, wherein the metadata comprises information about which version of each object is latest in the system: user accessible means for manipulating said object model to define and modify (a) properties of objects thus represented, and (b) relationships between such objects; a link table for storing the relationships between objects, wherein the link table comprises: (a) a single link for storing a relationship between an element and a complex type, and (b) a collection for storing a relationship between a module and an element of the module; management function means for applying management functions to the objects, wherein the management functions comprise version control; means for extending said object model to handle a new type of object by automatically generating descendent class(es) for handling the new object within the object model and incorporating them into an XML management system runtime environment for participation in the object modeling process; and means for deploying XML schema fragments modelled by the object model into the XML-based computing environment.