Re: [Sqlrelay-discussion] Is it possible to do mdb->sqlrelay->mdb scheme?

[David M. <dav...@fi...>]

Hello,

Sorry for the delayed reply...

I'm not certain that you can do what you want with SQL Relay.

If your applications are accessing an MDB file, they are probably doing
it through an Access DLL or maybe an ODBC driver for Access databases.
If they are using an ODBC driver, then in theory, you could just change
the DSN to point to a different database, like postgres or mysql, or any
other db.  The only problem then is the format of the queries.  All
databases use slightly different query formats for higher level
functions.  Your app's simple selects, inserts and deletes might work,
but outer joins, subselects and so forth might not.

If the apps aren't using ODBC to access the database, then you'd need
something similar to SQL Relay's drop-in replacement library for MySQL,
but for Access, on windows.  You'd need a DLL that implements all of the
Access API functions that are called by your apps, but overrides them to
talk to a different database.  SQL Relay doesn't provide a library that
maps the Access API.

Since apps access mdb files directly by opening the file rather than
over a socket through an RDBMS, it's also not possible to put a proxy
between the app and the db other than to use the approach described
above.

Hopefully this is helpful, wish there was an easier solution.

Dave
dav...@fi...


On Thu, 2008-02-28 at 20:32 +0300, if wrote:
> Hello list!
> 
> I face a little challenge, that after some heavy googling seem to be
> not so little. Here's the problem:
> 
> We have custom (*cough* goverment) application for windows, that works
> with mdb files _only_. It runs on windows, it opens only predefined
> mdb file, and it is dumb and enerprisey, and the worst part -- we are
> locked to use it. There's no security in it, no logging, and no
> control over the user. It works with financial data, so i have to
> tighten it a bit.
> 
> I moved mdb file to linux samba server, and restricted access on
> network level. The next part is tricky. I need control at sql query
> level and make an alert system, because main threat is emloyees
> working with it. My plan is to inject sqlrelay between "fake" mdb file
> and some good database (think postgres). Or at least inject it between
> fake mdb and real mdb, and log sql, that will be sufficient for the
> first time. After that i'll write everything i need.
> 
> So the main question is -- how can i make this fake mdb file? Sqlrelay
> can make socket->mdb proxying, but can it make a reverse proxy? Than
> i'll just chain few instances together and get what i want.
> 
> I also looked at Perl::DBI Proxy guides, mdbtools guides -- all with no luck.
> Any, just any advice will be highly appreciated!
> 
> 
> Thanks for reading,
> regards,
> if
> 
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