MS Access DB used by both a local App and .net Web App

[JonnyD]

I am working on a project to build a reporting web app from an exsiting
database that is controled by a local application. The application that
has control over the database creates a lock file to the database and
at that point I can no longer access the database with my web app. Is
there anyway around this? All I need is read only access to the
database to get some report information to display on the web page.

The error I get on the web app when I try to access the locked db is
"Could not use ''; file already in use."

Anyone have experiance with this?

[John Timney \( MVP \)]

I guess it depends on how big your database is? Its only one option.....and
may be entirely unsuitable for your needs.

--
Regards

John Timney
ASP.NET MVP
Microsoft Regional Director

"JonnyD" <ma*********@gm ail.com> wrote in message
news:11******** **************@ g47g2000cwa.goo glegroups.com.. .

I would like the data to be as real time as possable though, would it
be slow if i were to copy the db for every page refresh, or even
everytime a querry is run?

[Mark Rae]

"Juan T. Llibre" <no***********@ nowhere.com> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

In a anonymous-access web application there's only one user.
Yes, but the OP is talking about sharing the same Access database between
internal users over a network and external users over the web.
I've run web applications with a sustained 60+
concurrent connections without a problem.
OK - I was under the impression that there was some intentional internal
limit to the number of concurrent connections.
Fine-tuning your connections ( releasing them
as soon as you're done with them ) helps a lot.

Yes indeed - good advice, and not just for Access... :-)

[Juan T. Llibre]

re:

Yes, but the OP is talking about sharing the same Access database between internal users
over a network and external users over the web.
OK, I didn't see that.

re: OK - I was under the impression that there was some intentional internal limit to the
number of concurrent connections.
MSDE does that, but not Access.

But, there isn't really a "limit" to the number of connections in MSDE.

What happens is that, after 8 concurrent connections have been reached,
MSDE will throttle down the new connections, although none are denied.

They will all be served, with a slight delay for all connections above 8.


Juan T. Llibre, ASP.NET MVP
ASP.NET FAQ : http://asp.net.do/faq/
Foros de ASP.NET en Español : http://asp.net.do/foros/
=============== =============== ========
"Mark Rae" <ma**@mark-N-O-S-P-A-M-rae.co.uk> wrote in message
news:uQ******** ******@TK2MSFTN GP15.phx.gbl... "Juan T. Llibre" <no***********@ nowhere.com> wrote in message
news:%2******** ********@TK2MSF TNGP12.phx.gbl. ..

In a anonymous-access web application there's only one user.

Yes, but the OP is talking about sharing the same Access database between internal users
over a network and external users over the web.

I've run web applications with a sustained 60+
concurrent connections without a problem.

OK - I was under the impression that there was some intentional internal limit to the
number of concurrent connections.

Fine-tuning your connections ( releasing them
as soon as you're done with them ) helps a lot.

Yes indeed - good advice, and not just for Access... :-)

[John Timney \( MVP \)]

You are of course correct - in that it "can" be shared. This was my chain of
thought:

Unless you open it in shared mode at connection time its pretty much a
single user database, as once its opened by anyone in exclusive mode its
locked for access to everyone else until that lock is cleared. .Also, if
you have any access client opening any tables for any form of schema
editing, you will by default lock it to that user alone and render the
database exclusively locked until that user releases the system - forcing
single use. This is a problem with shared Access databases, as you cant
compact or repair a shared DB file if the LDB claims its shared and you
could end up with a corrupted DB due to sharing problems and invalid record
locking. All round, Access is not the ideal choice for a shared
database.....

--
Regards

John Timney
ASP.NET MVP
Microsoft Regional Director

"Mark Rae" <ma**@mark-N-O-S-P-A-M-rae.co.uk> wrote in message
news:eF******** ******@TK2MSFTN GP09.phx.gbl...

"John Timney ( MVP )" <ti*****@despam med.com> wrote in message
news:uE******** ******@tk2msftn gp13.phx.gbl...

Well your problem is that Access is a single user database

That simply isn't true...
http://office.microsoft.com/en-gb/as...408601033.aspx

and sucks somewhat for this type of scneario.

That, however, is perfectly true.

[Greg Burns]

> re:

OK - I was under the impression that there was some intentional internal
limit to the number of concurrent connections.

MSDE does that, but not Access.

http://support.microsoft.com/default...23120121120120

Note Although a file-server solution can support up to 255 simultaneous
users, if the users of your solution will be frequently adding data and
updating data, it is a good idea for an Access file-server solution to
support no more than 25 to 50 users.

:)

[Juan T. Llibre]

Hi, Greg.

Don't forget that in an anonymous web environment there's only *one* user.

The caveats in :

"For each person who opens a shared database, the Jet database engine
writes an entry in the database's .ldb file. The size of each .ldb entry is 64 bytes.
The first 32 bytes contains the computer name (such as JohnDoe).
The second 32 bytes contains the security name (such as Admin)."

don't apply, since only one user is accessing the Access db.

But, the limits to Access db's are quite evident.
For web usage, MSDE, and now SSE, are far better choices.

Juan T. Llibre, ASP.NET MVP
ASP.NET FAQ : http://asp.net.do/faq/
Foros de ASP.NET en Español : http://asp.net.do/foros/
=============== =============== ========
"Greg Burns" <greg_burns@DON T_SPAM_ME_hotma il.com> wrote in message
news:Ob******** *****@TK2MSFTNG P09.phx.gbl...

re:

OK - I was under the impression that there was some intentional internal limit to the
number of concurrent connections.

MSDE does that, but not Access.

http://support.microsoft.com/default...23120121120120

Note Although a file-server solution can support up to 255 simultaneous users, if the
users of your solution will be frequently adding data and updating data, it is a good
idea for an Access file-server solution to support no more than 25 to 50 users.

:)

[Paul Clement]

On 28 Oct 2005 15:22:32 -0700, "JonnyD" <ma*********@gm ail.com> wrote:

¤ I am working on a project to build a reporting web app from an exsiting
¤ database that is controled by a local application. The application that
¤ has control over the database creates a lock file to the database and
¤ at that point I can no longer access the database with my web app. Is
¤ there anyway around this? All I need is read only access to the
¤ database to get some report information to display on the web page.
¤
¤ The error I get on the web app when I try to access the locked db is
¤ "Could not use ''; file already in use."
¤
¤ Anyone have experiance with this?

You're probably on the right track. The .LDB file is usually the stinker in this scenario and
typically requires that any user accessing the database have *full* access to the folder where the
database is located. That would be first thing I would check.
Paul
~~~~
Microsoft MVP (Visual Basic)