Any good 'free' object database on linux

From: "Kimbro Staken"Subject: Re: Any good 'free' object database on
linux


> It is a database designed to store objects. Now isn't that helpful.
> :-)
>
> An object database is tightly coupled to an object oriented
> programming language and allows you to persist object instances
> between invocations of a program. Most implementations are for C++,
> Java, Smalltalk and recently Python though never at the same time.

Why would Python need it? Doesn't the pickle module/object do that
for it?