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?
You may be referring to a Federated Database System.