We can never know what might have been. In the meantime, however, we must still contend with the problem of very sensitive data. The owners of certain data don’t want to let their information anywhere near a common data warehouse. In such cases, the notion of “federated” information suggests an approach that may be more applicable.“It’s a way to have integration without centralization,” explains Nelson Mattos, director of information integration at IBM, which is forcefully developing this approach. The idea is to leave each data repository where it is-forget the warehouse-and instead provide it with a “wrapper”: a piece of software that knows how to translate the inner workings of that particular database to and from a standardized query language. This way, says Mattos, “a single query can be sent out to access all forms of information, wherever it’s stored.” The answers that come back are arrayed on the user’s screen in neat rows and columns, as if, he explains, they had been “all stored in a single database.”
This architecture solves the compatibility problem automatically, Mattos says. It also helps to ensure that sensitive information goes only to the right people. In a federated system, he says, “I continue to own my data. But I can write a wrapper that allows outsiders to access parts of my data, without giving away the whole thing.” The wrapper around a medical database might answer queries from public health officials about statistical information while denying access to information about specific patients. Likewise, the wrapper around an intelligence database might protect sources and methods. Such a system might be augmented by digital rights management, which could make it impossible to copy a digitally shared document.