At 05:39 PM 31/05/2004 +0000, you wrote:

>In his book Mastering Delphi7 Marco Cantu talks about using a remote
>data module in an application that, when compiled acts as an
>application server for three tier access to the Interbase database.
>
>Is this a necessary step, or is it ok just to have data modules as
>part of the client app?

The standard, two-tier client/server model has the data access layer in the
client app - the standard client/server configuration. A "remote" data
module is remote from the client but local to the server. That's the model
that Marco's book addresses. A very common model is for the data module to
be a web module, with the clients accessing the database from web browsers
- "intranet" (if it is within a single enterprise) or "extranet" (if
clients are accessing the system from the web or another wide-area network).

In other multi-tier modules, e.g. hybrid server networks, the remote data
module might be remote from both client and server and there might be
several database servers in the overall architectures. These models come
in various forms, broadly described as "distributed systems".

Helen