Abstract: Method and system aspects for achieving directed acyclic graph (DAG) representations of data in XML are described. The aspects include augmenting a document type definition (DTD) for allowing description of the DAG in an XML file and for providing functionality for a document object model application program interface (DOM API) to process the XML file.

Abstract: A method and system for specifying sub-elements and attributes in a sub-tree and for extracting data values is disclosed. The method and system include defining content elements as recursively hierarchical sub-trees by defining a first XML ELEMENT in a document type definition, where each content element includes a top-level element and zero or more embedded subelements, and wherein leaf nodes in the sub-trees represent data values. The method and system further include extracting data values from the content elements by using the description of the first XML ELEMENT to recursively traverse each top-level element and extract the data values from the sub-tree.