Hi,

we're currently looking for an XML database to store a variety of
small-to-medium sized XML documents. The XML documents are
unstructured in the sense that they do not follow a schema or DTD, and
that their structure will be changing over time. We'll need to do
efficient searching based on elements, attributes, and full text
within text content. More importantly, the documents are mutable.
We'll like to bring documents or fragments into memory in a DOM
representation, manipulate them, then put them back into the database.
Ideally, this should be done in a transaction-like manner. We need to
efficiently serve document fragments over HTTP, ideally in a manner
that allows for scaling through replication. We would prefer strong
support for Java integration, but it's not a must.

Have other encountered similar problems, and what have you been using?

So far, we're researching: eXist-DB (http://exist.sourceforge.net/ ),
Base-X (http://www.basex.org/ ), MonetDB/XQuery
(http://www.monetdb.nl/XQuery/ ), Sedna
(http://modis.ispras.ru/sedna/index.html ). Wikipedia lists a few
others here: http://en.wikipedia.org/wiki/XML_database
I'm wondering to what extent systems such as Lucene, or even digital
object repositories such as Fedora could be coaxed into this usage
scenario.

Thanks for any insight you have or experience you can share.

 - Godmar