Re: Mixing OO and DB

From: David Cressey <>
Date: Mon, 25 Feb 2008 15:13:57 GMT
Message-ID: <VWAwj.2353$A93.1891_at_trndny08>

"Robert Martin" <> wrote in message news:2008022409121816807-unclebob_at_objectmentorcom...

> Now, if we take that one step further, and swap in a dummy database
> engine, and have the application access it through a polymorphic
> interface, we have true OO.

Something vaguely like that has been done. It's not a "dummy database engine", but rather
different versions of the "real" database engine, coexisting under a single system.

A client that issues a "connect" to start a session with a given database does not necessarily "know" which version of the DB engine has responded to the request for a connection. (There is a way to find out, but that may not be coded into an application). The operations issued via the connection could be implemented quite differently in the two versions of the DB engine, but the difference is supposed to be transparent to the client. Received on Mon Feb 25 2008 - 16:13:57 CET

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