16. The computer-implemented structure of claim 13 in which the document identifier is a unique identifier for each different XML document.
13. A computer-implemented structure for storing XML data in a relational database, the computer implemented structure comprising a first table structure, the first table structure comprising: a document identifier stored in a volatile or non-volatile computer usable storage medium corresponding to an XML document; a path string for a node within the XML document stored in the volatile or non-volatile computer usable storage medium, wherein the path string comprises a full path for the node from a root node of the XML document; hierarchical information for the node stored in the volatile or non-volatile computer usable storage medium; and node data for the node stored in the volatile or non-volatile computer usable storage medium.