Updating xml document
It is a good bet that your data has a highly regular structure and is used by non-XML applications.
Furthermore, things like entities and the encodings used by XML documents probably aren't important to you -- after all, you are interested in the data, not how it is stored in an XML document.
On the other hand, suppose you have a Web site built from a number of prose-oriented XML documents.
On the minus side, it lacks many of the things found in real databases: efficient storage, indexes, security, transactions and data integrity, multi-user access, triggers, queries across multiple documents, and so on.This will allow you to preserve physical document structure, support document-level transactions, and execute queries in an XML query language.