For inserting an XML document into your DB , have a look at this page i think its useful
http://www.oracle.com/technology/sample_code/tech/java/codesnippet/xmldb/HowToLoadLargeXML.html#PLSQLCode
H
ave a look at this manual to use XMLPARSER which will help you parse your XML document and extract any information about the nodes without the need to parse any strings
http://www.acs.ilstu.edu/docs/Oracle9iAS/web.902/a88894/adx28ppl.htm
Hope that helps !