Multi-database object-oriented proxy

Do you know if there is a system/product/technique which would allow to "wrap" one or more relational databases into one object-oriented virtual database (or could we call it a "multi-database object-oriented proxy")?

Let me illustrate the principle:

So, basically, the pink thing in the middle (hereafter "object proxy") would contain definitions of business entities and their mappings to data in multiple relational databases. Applications would request or insert/update/delete data from the object proxy, which would magically synchronize with underlying relational databases.

Is that possible? Does such a system exist?

Do you mean products like InfoSphere Federation Server or WebSphere Federation Server? As variant it is possible, on my opinion, to use microsoft's implementation based on sql server partitioned tables and some ORM (Nhibernate or Entity Framework). And, of course: Cloud-based database solution

ADDED:

Maxim, please review this presentation (page #74): Not Only SQL (NOSQL) and you will find names of some non relational databases. it can help you, i think:

• Hypertable

• HBase

• ..

StackExchange Database Administrators Q#728, answer score: 4