The most widely used deployed database is likely sqlite. It has something like 1/2 a billion installs and is mentioned on the referenced "Embedded Database" Wikipedia page.<p>As a Python user, I'm happy that sqlite support is part of the standard library since 2.5's release in 2006. So I'm surprised to read "that the time to use an embedded db has come" when I thought it had been part of the standard toolbase for around for a while.