I have you some information about XML Namespaces and XML Linking.
XML give as facility to make our own tags. Suppose if we want add element of two XML sheets their may be conflicts. But if we made our own tags than it can solve the problem of data conflicts,because different tags may contain the same type of data.
Using XML linking we can create the connection among the XML data means they can communicate each other.
XML Linking(XML Link,XML Pointer & XML Base)
XML Link is used to insert link into XML Sheets.
XML Pointer is used to link the address of some specific data in XML sheets.
XML Base is used to defining a default reference to external XML resources.