Xindice (pronounced “zeen-dee-chay”) is an open source native XML database from the Apache Software Foundation.
You might be wondering what a native XML database is good for? Well it pretty much has one purpose, storing XML data. … The benefit of a native solution is that you don’t have to worry about mapping your XML to some other data structure. You just insert the data as XML and retrieve it as XML. … This is especially valuable when you have very complex XML structures that would be difficult or impossible to map to a more structured database. … At the present time Xindice uses XPath for its query language and XML:DB XUpdate for its update language.