db4o is not unique in the claims it makes. I can store objects from any language in any database. The only requirement, and the reason why db4o only supports ja

db4o is not unique in the claims it makes. I can store objects from any language in any database. The only requirement, and the reason why db4o only supports java and .NET, is that the language must support serialization of the object in both directions. I have used this methodology along with Memcache (as a real-time database) in C#, PHP, Python, and Java, as well as storing those objects to PostgreSQL databases. That said, I don't think I would use db4o simply based on it's claim to be able to store serialized objects. PostgreSQL, my database of choice, has trillions of user hours on it and is well supported by hundreds of thousands of users. NoSQL databases store the tuples (or tuple-like structures) in indexed form, which is convenient but can be inefficient. I prefer to store only the pertinent tuples for indexing, and the serialized blob by itself as a non-indexed element.