I am working on a map rendering application and would like to hook it up to a current GIS database to get shapefiles and other data. One possible data resource I have looked at is OpenStreetMap. For my application I would want to have the data locally for processing, so I would need to mirror the database. I know that I can get a dump of the whole database, but ideally I would like to get dynamic updates to my dump as the data is improved; hence I am looking for more like a mirroring functionality. Does OpenStreetMap allow for their whole database to be locally mirrored by users, or does it only allow localized queries?
You can have raw OSM data in a database, even for regional extracts, and then apply daily, hourly or minutely updates via small diff files.
See the OSM wiki about planet.osm and its section about "Update frequency".
Tools mentioned there are osmosis or OSMupdate.
Or see help.osm.org about "How to maintain a local copy of a specific area of the OSM database"