You can use MDB (database) via ODBC with any ODBC-compliant server database,
including Microsoft SQL Server, as well as for single-user databases, as
well as for multi-user environments.
Conversely, you can use an ADP (project) with the ADODB data provider for
the Jet database engine, as well as for connecting to Microsoft SQL Server.
However, the most recent word from the knowledgeable Microsoft insiders is
that the MDB - Jet - ODBC - Server arrangement turns out to be better than
ADP - ADODB - SQL Server, and to have been so all through the hype about how
much better the ADPs were with server DBs.
I have personally worked on MDB - Jet - ODBC - server databases since the
days of Access 2.0, using various server databases (including Microsoft SQL
Server, Sybase SQL Server, Sybase SQL Anywhere, and Informix). The largest
of these had just under 200 users in a WAN environment; the smallest had
only a few users and was done with a server database for reasons of
reliability and recoverability.
I am currently doing some enhancement work on a client's ADP, and they are
generally happy with its performance.
I'd expect that developing a new Access project would take a bit longer for
comparable functionality simply because there seems to be more VBA code
involved. However, in the relatively few ADPs that I have examined, that may
have been more a matter of the original developer's mindset than of
necessity for an Access project. (I have also seen a few MDBs, over the
years, where there was far more code than actually was needed, too.)
Larry Linson
Microsoft Access MVP