OpenSource ObjectOrientedDatabase**s:
- PERST (http://www.Perst.Org)
- Mature, fast, native C#, robust, m-s replication, simple
- db4o (DeeBeeFourOh) http://www.db4o.com
- GOODS (http://www.garret.ru/~knizhnik/goods.html)
- OzoneDb (http://ozone-db.org)
- ZODB (Z Object Database) http://www.zope.org/Wikis/ZODB/FrontPage :
- Mature software, widely used (all ZopeApplicationServer/Plone CMS installations, but also used standalone)
- Very flexible with mountable sub-databases and a wide number of storage backends, including SQL
- Scales to any need using ZEO
- Active development
- Magma (http://wiki.squeak.org/squeak/2665)