The following sections show how users can store XML documents into XML type columns and retrieve them via SQL queries that either retrieve the entire document or evaluate an XPath/XQuery expression that returns a single document node.
Consider the following queries:
SELECT id, xmldoc FROM xmltab;
SELECT id, xmldoc.xmlextract('.', NULL) FROM xmltab;
The result of each query represents a single tree rooted in a document node. The server returns the serialized representation of the document. The serialization of the document is not guaranteed to be lexically equivalent to the document that was inserted, but it will be semantically equivalent (the canonical representation of the original document that was inserted and the document retrieved will be lexically equivalent). Drivers can either parse the document returned or pass on the stream to applications.