SQL Server Emulation
Lowden, James K
LowdenJK at bernstein.com
Tue Jun 19 16:06:10 EDT 2001
Yes, it's been thought of;
yes, you'll get help here;
yes, there's some abandoned code already;
yes, it's a good idea;
yes, it's feasible.
In a word, yes. Depending on your skill and expectations, of course.
In the source code tree you'll find server emulation code. It doesn't pass
anything anywhere else; it's purpose is to pretend to be a server when none
One pleasant design would be a port-to-port filter that, say, accepted
connections on port 1433 and formed connections to the real server on, oh,
2500 or whatever. That would offer direct access to the real backend on the
real port and emulated access on the emulator's port. Also, such a filter
could be installed on the server or the client (or somewhere else, for that
The protocol-level stuff is only one hurdle, of course. Unless you're going
to get a lot more ambitious and parse the SQL, the applications that could
use your emulator are going to be constrained to the subset SQL shared
between SQL Server and the real backend.
From: Antonio Ognio [mailto:ognio at peruserver.com]
Sent: June 19, 2001 2:17 PM
To: TDS Development Group
Subject: [freetds] SQL Server Emulation
I'm joining the list to learn about TDS and FreeTDS and specially
to explore the idea of a deamon listing and serving TDS but using
another database as a the real backend, e.g. PostgreSQL.
I'm starting to think of this as some sort of SQL Server emulator.
I guess the tough part is developing the "server" part. This "emulator"
might even be configurable to act as a client to different databases
for the the real backend.
Does somebody has a project like this in mind? Has somoene seen or
heard something related to this idea?
I can code some C. Is all what I need inside the sources of FreeTDS?
You think a server might be coded just looking in the sources of
FreeTDS? What other considerations are needed?
Many people in commercial enviroments seem to have applications
(usually with no access to source code) designed to work with
SQL server. I work developing PHP apps and giving some basic
linux consultancy so many people talk about this to me.
If this people could replace their NT/Win2k boxes running SQL Server
with Linux Boxes running MySQL or PostgreSQL (or even Oracle when
available) many would move to Linux even at the costs in performance
this sort of solution would have.
In developing countries like mine, IT managers are very price
sensitive and many are willing to move to Linux. I believe a technology
like this could attract many people.
Thanks a LOT for your time and guidance.
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