11. The method of claim 8 , wherein the database schema comprises a predefined database schema comprising a set of java classes representative of one or more nodes and one or more fields of the hierarchical database.
8. A method for defining a metadata schema to facilitate passing data between an eXtensible Markup Language (XML) document and a hierarchical database, the method comprising: accessing a database schema indicative of database field names and a hierarchical structure for a hierarchical database; accessing a document schema that defines the hierarchical structure, content data syntax, and semantics of valid, well-formed, XML documents that can be passed into and out of the hierarchical database, the document schema including an XML element name that maps to a database field name in the database schema; relating the database schema and the document schema to provide a metadata schema that enables data to be passed between an XML document and the hierarchical database; and wherein the document schema comprises at least one directive metadata element configured to not interfere with third-party applications using the document schema and to facilitate passing data between the XML document and the hierarchical database.