Alternatives to decompiling MS Access MDE files - ms-access

I've been tasked with finding a suitable tool to decompile MDE files. The MDEs were created by staff who have since left (familar story eh?) and we do not have access to the originally MDB files.
The reason we need access to the original code is that the data source is changing (the backend as well as some of the table and queries) and we need a way to update queries. An example of a change, in a SELECT statement where is the WHERE clause looks for zero as a string ("0") rather than an integer.
I'm aware that unless you use the services of people like EverythingAccess.com its unlikely you will ever get the source code back.
My main query is to ask for alternative methods to decompiling code. An example of the kinds of methods I'm thinking about is to spy on the traffic between the app the the ODBC DSN using tcpdump. I might then be able to write code to translate the data source queries between the old and new systems.
Ideally I'd prefer a solution that is application centric rather than one that analyses all network traffic.
I should add one caveat, no doubt most of you are thinking the best solution is to rewrite the code, based on its perceived functionality. This is the option we're not considering (at the moment).

Queries and linked tables can be changed in an MDE.
Alternatively see Converting a Microsoft Access MDE file back into an MDB file. Section 2 for some tips
I see you're already aware of MDE to MDB Conversion Service for Microsoft Access Wayne has stated he will require proof that you own the code.

Related

Dynamically changing Report's Shared Data Source at Runtime

I'm looking to use SSRS for multi-tenant reporting and I'd like the ability to have runtime-chosen Shared Data Sources for my reports. What do I mean by this? Well, I could be flexible but I think the two most likely possibilities are (however, I'm also open to other possibilities):
The Shared Data Source is dictated by the client's authentication. In my case, the "client" is a .NET application and not the user, so if this is a viable path then I'd like to somehow have the MainDB (that's what I'm calling it) Shared Data Source selected by the Service Account that the client logs in as.
Pass the name of the Shared Data Source as a parameter and let that dictate which one to use. Given that all of my clients are "trusted players", I am comfortable with this approach. While each client will have its own representative Service Account, it's just for good measure and should not be important. So instead of just calling the data source MainDB, we could instead have Client1DB and Client2DB, etc. It's okay if a new data source means a new deployment but I need this to scale easily enough as well to ~50 different data sources over time.
Why? Because we have multiple/duplicate copies of our production application for multiple customers but we don't want to duplicate everything, just the web apps and databases. We're fine with some common "back-end" things. And for SSRS, because of how expensive licenses are (and how rarely reports are ran by our users), we really want to have just a single back-end for all of our customers (I actually have a second one on standby for manual disaster recovery situations - we don't need to be too fancy here as reports are the least important DR concern we have).
I have seen this question which points to this post but I was really hoping there was a better way than this. Because of all of those additional steps/efforts/limitations/etc, I'd rather just use PowerShell to script duplicate deployments of the reports with tweaked hardcoded data sources instead of standardizing on the steps in that post. That solution feels WAY too hacky to me and doesn't seem to scale very well at all.
I've done this a bunch of terrible ways (usually hardcoded in a dynamic script), and then I discovered its actually quite simple.
Instead of using Shared Connection, use the Embedded Connection and create your Connection string based on params (or any string manipulation code)....

MS Access - Linked tables vs Access Data Project (ADP)? Security?

I am trying to determine the best approach when designing a new Access based application. Due to decisions made by others I have to use Access 2003 as my front end and SQL Server as my back-end data store (I would have preferred to use Winforms/WPF and SQL Server 2008 but that is another story).
Originally I was thinking of using Access Data Projects (ADP) as data security is a big issue in this project and ADPs would allow me to store everything (except VBA. reports, and forms) within SQL Server. Problem is that many developers I have spoken to suggest that using ADO is something that Microsoft has tried and then abandoned. They suggest using linked tables will provide a more consistent and less buggy experience.
I was hoping to get some feedback on what others think the best solution might be. Additionally, I would be interested to know if others consider linked tables to be a security risk over ADP. Thanks for any assistance.
Edit ... just wanted to add that the number of people using this application will be small (10 to 20). I should also add that this application is being developed from scratch. No conversion is needed.
ADPs have had no significant features added in a number of versions now. They also have some quirks compared to MDB/ACCDBs. There are probably less than 1% of the folks using ADPs who use MDBs/ACCDBs so support is much better for MDBs/ACCDBs.
The ADO part is immaterial as you can use either ADO or DAO.
If you use Windows authentication then there is no real difference between ADPs and linked tables as userid and passwords aren't stored in the linked tables metadata.
The number of users is immaterial. There is no reason why you couldn't have thousands of users in an Access FE against a SQL Server BE.

How to set up a development environment in MS Access

I have created an MS Access 2003 application, set up as a split front-end/back-end configuration, with a user group of about five people. The front end .mdb sits on a network file server, and it contains all the queries, forms, reports, and VBA code, plus links to all the tables in the back end .mdb and some links to ODBC data sources like an AS/400. The back end sits on the same network file server, and it just has the table data in it.
This was working well until I "went live" and my handful of users started coming up with enhancement requests, bug reports, etc. I have been rolling out new code by developing/testing in my own copy of the front-end .mdb in another network folder (which is linked to the same back-end .mdb), then posting my completed file in a "come-and-get-it" folder, alerting the users, and they go copy/paste the new front-end file to their own folders on the network. This way, each user can update their front end when they're at a 'stopping point' without having to boot everyone out at once.
I've found that when I'm developing now, sometimes Access becomes extremely slow. Like, when I am developing a form and attempt to click a drop-down on the properties box, the drop-down arrow will push in, but it will take a few seconds before the list of options appears. Or there's tons of lag in selecting & moving controls on a form. Or lots of keyboard lag.
Then, at other times, there's no lag at all.
I'm wondering if it's because I'm linked to the same back end as the other users. I did make a reasonable effort to set up the queries, forms, reports etc. with minimal record locking, if any at all, depending on the need. But I may have missed something, or perhaps there is some other performance issue I need to address.
But I'm wondering if there is an even better way for me to set up my own development back-end .mdb, so I can be testing my code on "safe" data instead of the same live data as the rest of the users. I'm afraid that it's only a matter of time before I corrupt some data, probably at the worst possible moment.
Obviously, I could just set up a separate back-end .mdb and manually reconfigure the table links in the front end every time, using the Linked Table Manager. But I'm hoping there is a more elegant solution than that.
And I'm wondering if there are any other performance issues I should be considering in this multi-user, split database configuration.
EDIT: I should have added that I'm stuck with MS Access (not MS-SQL or any other "real" back end); for more details see my comment to this post.
If all your users are sharing the front end, that's THE WRONG CONFIGURATION.
Each user should have an individual copy of the front end. Sharing a front end is guaranteed to lead to frequent corruption of the shared front end, as well as odd corruptions of forms and modules in the front end.
It's not clear to me how you could be developing in the same copy of the front end that the end users are using, since starting with A2000, that is prohibited (because of the "monolithic save model," where the entire VBA project is stored in a single BLOB field in a single record in one of the system tables).
I really don't think the problems are caused by using the production data (though it's likely not a good idea to develop against production data, as others have said). I think they are caused by poor coding practices and lack of maintainance of your front end code.
turn off COMPILE ON DEMAND in the VBE options.
make sure you require OPTION EXPLICIT.
compile your code frequently, after every few lines of code -- to make this easy, add the COMPILE button to your VBE toolbar (while I'm at it, I also add the CALL STACK button).
periodically make a backup of your front end and decompile and recompile the code. This is accomplished by launching Access with the /decompile switch, opening your front end, closing Access, opening your front end with Access (with the SHIFT key held down to bypass the startup code), then compacting the decompiled front end (with the SHIFT key held down), then compiling the whole project and compacting one last time. You should do this before any major code release.
A few other thoughts:
you don't say if it's a Windows server. Linux servers accessed over SAMBA have exhibited problems in the past (though some people swear by them and say they're vastly faster than Windows servers), and historically Novell servers have needed to have settings tweaked to enable Jet files to be reliably edited. There are also some settings (like OPLOCKS) that can be adjusted on a Windows server to make things work better.
store your Jet MDBs in shares with short paths. \Server\Data\MyProject\MyReallyLongFolderName\Access\Databases\ is going to be much slower reading data than \Server\Databases. This really makes a huge difference.
linked tables store metadata that can become outdated. There are two easy steps and one drastic one to be taken to fix it. First, compact the back end, and then compact the front end. That's the easy one. If that doesn't help, completely delete the links and recreate them from scratch.
you might also consider distributing an MDE to your end users instead of an MDB, as it cannot uncompile (which an MDB can).
see Tony Toews's Performance FAQ for other generalized performance information.
1) Relink Access tables from code
http://www.mvps.org/access/tables/tbl0009.htm
Once I'm ready to publish a new MDE to the users I relink the tables, make the MDE and copy the MDE to the server.
2) I specifically created the free Auto FE Updater utility so that I could make changes to the FE MDE as often as I wanted and be quite confident that the next time someone went to run the app that it would pull in the latest version. For more info on the errors or the Auto FE Updater utility see the free Auto FE Updater utility at http://www.granite.ab.ca/access/autofe.htm at my website to keep the FE on each PC up to date.
3) Now when working on site at a clients I make the updates to the table structure after hours when everyone is out of the system. See HOW TO: Detect User Idle Time or Inactivity in Access 2000 (Q210297) http://support.microsoft.com/?kbid=210297 ACC: How to Detect User Idle Time or Inactivity (Q128814) http://support.microsoft.com/?kbid=128814
However we found that the code which runs on the timer event must be disabled for the programmers. Otherwise weird things start happening when you're editing code.
Also print preview would sometimes not allow the users to run a menu item to export the report to Excel or others. So you had to right click on the Previewed report to get some type of internal focus back on the report so they could then export it. This was also helped by extending the timer to five minutes.
The downside to extending the timer to five minutes was if a person stays in the same form and at the same control for considerable parts of the day, ie someone doing the same inquiries, the routine didn't realize that they had actually done something. I'll be putting in some logic sometime to reset this timer whenever they do something in the program.
4) In reference to another person commenting about scripts and such to update the schema see Compare'Em http://home.gci.net/~mike-noel/CompareEM-LITE/CompareEM.htm. While it has its quirks it does create the VBA code to update tables, fields, indexes and relationships.
Use VBA to unlink and re-link your tables to the new target when switching from dev to prod. It's been to many years for me to remember the syntax--I just know the function was simple to write.
Or use MS-Access to talk to MS-Access through ODBC, or some other data connection that lives outside of the client mdb.
As with all file base databases, you will eventually run into problems with peak usage or when you go over a small magical number somewhere between 2 and 30.
Also, Access tends to corrupt frequently, so backup, compact and repair need to be done on an frequent basis. 3rd party tools used to exist to automate this task.
As far as performance goes, the data is being processed client side, so you might want to use something like netmeter to watch how much data is going over the wire. The same principle about indexing and avoiding table scans apply to file base dbs as well.
Many good suggestions from other people. Here's my 2 millicents worth. My backend data is on server accessed through a Drive mapping. In my case, the Y drive. Production users get the mapping through a login script using active directory. Then the following scenarios are easily done by batch file:
Develop against local computer by doing a subst command in a batch file
run reports against last nights data by pointing Y to the backup server (read only)
run reports against end of month data by pointing to the right directory
test against specialized scenarios by keeping a special directory
In my environment (average 5 simultaneous users, 1000's of rows, not 10,000's.) corruption has occurred, but it's rare and manageable. Only once in the last several years have we resorted to the previous days backup. We use SQL Server for our higher volume stuff, but it's not as convenient to develop against, probably because we don't have a SQL admin on site.
You might also find some of the answers to this question (how to extract schemas from access) to be useful as well. Once you've extracted a schema using one of the techniques that were suggested you gain a whole range of new options like the ability to use source control on the schemas, as well as being able to easily build "clean" testing environments.
Edit to respond to comment:
There's no easy way to source control an Access database in it's native format, but schema files are just text files like any other. Hence, you can check them in and out of the source control software of your choice for easy version control/rollbacks.
Or course, it relies on you having a series of scripts set up to re-build your database from the schema. Once you do, it's normally fairly trivial to create an option/alternative version that rebuilds it in a different location, allowing you to build test environments from any previous committed version of the schema. I hope that clarifies a bit!
If you want to update the back end MDB schema automatically when you release a new FE to the clients then see Compare'Em http://home.gci.net/~mike-noel/CompareEM-LITE/CompareEM.htm will happily generate the VBA code need to recreate an MDB. Or the code to create the differences between two MDBs so you can do a version upgrade of the already existing BE MDB. It's a bit quirky but works.
I use it all the time.
You need to understand that a shared mdb file for the data is not a robust solution. Microsoft would suggest that SQL Server or some other server based database would be a far better solution and would allow you to use the same access front end. The migration wizard would help you make the changeover if you wanted to go that way.
As another uses pointed out, corruption will occur. It is simply a question of how often, not if.
To understand the performance issues you need to understand that to the server the mdb file with the data in it is simply that, a file. Since no code runs on the server, the server does not understand transactions, record locking etc. It simply knows that there is a file that a bunch of people are trying to read and write simultaniously.
With a database system such as SQL Server, Oracle, DB2. MySQL etc. the database program runs on the server and looks to the server like a single program accessing the database file. It is the database program (running on the server) that handles record locking, transactions, concurrency, logging, data backup/recovery and all the other nice things one wants from a database.
Since a database program designed to run on the server is designed to do that and only that, it can do it far better and more efficently that a program like Access reading an writing a shared file (mdb).
There are two rules for developing against live data
The first rule is . . . never develop
against live data. Not ever.
The second rule is . . .never develop
against live data. Not ever.
You can programatically change the bindings for linked tables, so you can write a macro to change your links when you're deploying a new version.
The application is slow because it's MS Access, and it doesn't like many concurrent users (where many is any number > 1).

Working with multiple programmers on MS Access

Would you recommend working with multiple programmers on an MS Access application?
One of our MS Access application has grown to the point where the number of changes (bug fixes) and new features can no longer be handled by one programmer in the requested time frame.
We are trying to introduce version control using the undocumented SaveAsText and LoadFromText procedures in VBA to make collaboration on this application possible. Unfortunately we have already run into problems loading modified forms and reports back into Access as a checksum is stored in every form text file.
Before putting time into building an import/export application to compile text files into an Access database, we would like to hear your recommendations.
I think you should avoid this path at all cost, and try and persuade management into redevelopment.
It's a bitter pill to swallow, but this is going to need to be redeveloped sooner or later, and you are just saving them time and money.
We were using Microsoft's own version control add-in for MS Access 2000/2002/2003 for about 5 years now, and I can't remember a single serious problem. Usability of this add-in barely deserves a "B", but it must be much, much more convenient than fiddling with any ad-hoc method involving manual or semi-manual exporting/importing of Access forms, modules, etc.
We were using VSS as a version control system all the time. No problems whatsoever. However, if you have some good reasons to avoid VSS, you may have some options:
The version control add-in that we were using does not require VSS. Theoretically it can be used with any version control system that implements Microsoft Source Code Control Interface (MSCCI). For example, when we had to let somebody work on this project remotely, we used SourceOffsite by SourceGear. Access version control add-in worked with this third-party product fairly well (not without some quirks, but well enough). So, if your favorite version control system complies with MSCCI, you could try to use it.
Now that Microsoft has this Team Foundation thingy, apparently there are other options to be used to integrate MS Access with version control. We did not explore this path, though. This article may be a good start for exploring it.
Hope this would be of some help. :-)
P.S. I am not a big fan of MS Access. In fact, I rather hate it as a platform for a user front-end. If I had a choice, I would run away from it yesterday. :-) However, I must admit that existence of this version control add-in is one of the few things that makes maintenance of our old Access+SQLServer project more or less tolerable. :-))
In addition to what I already said here, I should add that the whole system works very well. The comparison process takes less than 30 minutes a week, for a team of 3 programmers. So let's describe it a little bit.
We have basically 2 versions of our Access program:
The "Developer's version", with all the stuff in it.
We each begin to work with an identical version of our developer's edition. As each one modifies or add parts of the code, we have to run some comparison routine on a regular basis. To do so, we have an object-export routine to a common "comparison" folder. An object (module for example) is exported as a text file (saveAsText command, do not work with tables, see infra), it will be compared to the existing equivalent text files in the folder. If files are identical, there is no file exported. If files are different, the new module is exported with the developer's name as an addition to the file name (if modQueries.txt exists, then modQueries_philippe.txt is created...). Of course if there is no equivalent .txt file in the folder, it will be created at first export.
At the end of the period, we would get in our folder the following files
modQueries.txt, being the first "original", last common version of the module
modQueries_Philippe.txt, with Philippe's modifications
modQueries_Denise.txt, with Denise's modifications
As the module was not modified by other developers, their export did not lead to the creation of a specific modQueries_developersName.txt file
If for any reasons Denise exported many times her module, only the last version is in the comparison folder.
We can then compare (with a "text file" comparer) the different versions and create the "updated" version of the module. We have a screen giving us the number of objects in the comparison folder, number of version for each object, and it is even possible to open the file comparer directly from the developer's interface (We use "File Compare Tool" which has a command-line mode and can then be started directly from Access).
The forms compare issue is quite special, as one of our rules is to have no specific code in our forms (please see here for more details). Forms are then only for display, so usually we do not even compare them. We just make sure that each one of them is updated by only one person (which is quite logical).
The table compare issue (we have local tables) can be only made between mdb files. As we export one text file per module, we also export one mdb file per table. We have a small routine allowing us to identify table differences at the structure level or at the record level.
After each comparison procedure, a subroutine will use all the objects available ini the comparison folder and create a whole new clean mdb file from scratch. This is the new developer's version. Every developer can then copy it on his computer and continue his work.
Developer's versions do not have numbers, but contains last client version number.
The client version, with limited stuff, automatically distributed to users
Each developer has the possibility to build a "client" mdb for final users. This mdb is created from scratch, in a way quite similar to our developer's version, but not all objects are exported. Some specific switches are turned off (special keys, access to code, etc). This mdb holds a version number as a property. The version number is used to build the name of the mdb file.
At production time, this mdb file is zipped and placed in a specific "distribution" folder. Each time a user starts the app, it will automatically check this folder to see if a new version is available. If yes, the client mdb file is updated from the distribution folder, and the app is restarted.
This distribution folder is replicated at night time with our overseas agencies. Users abroad will then be able to install the new version on the following day.
Following the direction provided by Yarik we settled on continuing developing in Access using the Access Add-in Source Code Control, the SVN SCC API Plugin by PushOk Software and Subversion. This stack provides us with seamless Access integration, full-backup and restore and an open version control system.
We had to install a hotfix to Access 2003 and make sure the default database file type matched our database file type to make it work.
We will continue to update this answer with our findings.
Have look at this thread:
How do you use version control with Access development?
Sounds like a terribly painful way to do team development. If you have any options for porting to another environment like VS2008 that would be my recommendation.
There is no easy way to work on Access as a team and even version control might be a bit tricky.

Issues using MS Access as a front-end to a MySQL database back-end?

Two users wanted to share the same database, originally written in MS Access, without conflicting with one another over a single MDB file.
I moved the tables from a simple MS Access database to MySQL using its Migration Toolkit (which works well, by the way) and set up Access to link to those tables via ODBC.
So far, I've run into the following:
You can't insert/update/delete rows in a table without a primary key (no surprise there).
AutoNumber fields in MS Access must be the primary key or they'll just end up as integer columns in MySQL (natch, why wouldn't it be the PK?)
The tables were migrated to MySQL's InnoDB table type, but the Access relationships didn't become MySQL foreign key constraints.
Once the database is in use, can I expect any other issues? Particularly when both users are working in the same table?
I know this topic is not too fresh, but just some additional explanations:
If you want to use MS Access effectively, especially with bigger, multiuser databases, please do the following:
split your MDB into frontend application and backend (data only) files - you'll have two separate MDB files then.
migrate all the tables with data and structure into external database. It can be: MySQL (works very well, no database size limitations, requires some more skills as it's not MS technology, but it is a good choice in many cases - moreover you can scale your backend with more RAM and additional CPUs, so everything depends on your needs and hardware capabilities); Oracle (if you have enough money or some kind of corporate license) or Oracle 10g XE (if this is not a problem, that the database size is limited up to 4 GB and it will always use 1 GB of RAM and 1 CPU), MS SQL Server 2008 (it's a great pair to have MS Access frontend and MS SQL Server backend in all the cases, but you have to pay for license! - advantages are: close integration, both technologies are form the same vendor; MS SQL Server is very easy to maintain an effective at the same time) or Express edition (same story like with Oracle XE - almost the same limitations).
relink your MS Access frontend with backend database. If you selected MS SQL Server for the backend then it will be as easy as to use the wizard from MS Access. For MySQL - you have to use ODBC drivers (it's simple and works very good). For Oracle - please do not use the ODBC drivers from Microsoft. These from Oracle will do their work much better (you can compare the time needed to execute SQL query from MS Access to Oracle via Oracle ODBC and MS Oracle ODBC drivers). At this point you'll have solid database backend and fully functional MS Access frontend - MDB file.
compile your MDB frontend to MDE - it will give you a lot of speed. Moreover, it's the only reasonable form of distributing MS Access application to your end users.
for daily work - use MDE file with MS Access frontend. For futher MS Access frontend development use MDB file.
don't use badly written ActiveX components to enhance MS Access frontend capabilities. Better write them yourself or buy the proper ones.
don't believe into the myths that there are a lot of issues with MS Access - this is a great product which can help in may occassions. The problem is a lot of people assume it's a toy or that MS Access is generaly simple. Usually they generate a lot of errors and issues by themselves and their lack of knowledge and experience. To be successfull with MS Access it is important to understand this tool - this is the same rule, like with any other technology outhere.
I can tell you that I'm using quite advanced MS Access fronted to MySQL backend and I'm very satisfied (as a developer which is maintaining this application). My friends, the users are also satisfied as they feel very comfortable with the GUI (frontend), the speed (MySQL), they don't have any issues with records locking or database performance.
Moreover, it's important to read a lot about good practices and other people experiences. I would say that in many cases MS Access is a good solution. I know a lot of dedicated, custom made systems which started as an experiment in form of private MS Access database (MDB file) and then evolved to: splitted MS Access (MDE - frontend, MDB - backend) and finally to: MS Access frontend (MDE) and "serious" database backend (mainly MS SQL Server and MySQL). It's also important that you can always use your MS Access solution as a working prototype - you have ready to use backend in your database (MySQL - let's assume) and you can rewrite frontend to the technology of your choice (web solution? maybe desktop C# application - what you require!).
I hope I helped some of you considering the work with MS Access.
Regards,
Wawrzyn
http://dcserwis.pl
I had an application that worked likewise: an MS Access frontend to a MySQL backend. It was such a huge pain that I ended up writing a Win32 frontend instead. From the top of my head, I encountered the following problems:
Development of the ODBC link seems to have ceased long ago. There are various different versions floating around --- very confusing. The ODBC link doesn't support Unicode/UTF8, and I remember there were other issues with it as well (though some could be overcome by careful configuration).
You probably want to manually tweak your db schema to make it compatible with MS Access. I see you already found out about the needed surrogate keys (i.e., int primary keys) :-)
You should keep in mind that you may need to use pass-through queries to do more sophisticated SQL manipulations of the MySQL database.
Be careful with using lots of VBA, as that tends to corrupt your frontend file. Regularly compressing the database (using main menu, Tools | Database utilities | Compress and restore, or something like that --- I'm using the Dutch version) and making lots of backups is necessary.
Access tends to cause lots of network traffic. Like, really huge lots. I haven't been able to find a solution for that. Using a network monitor is recommended if you want to keep an eye on that!
Access insists on storing booleans as 0/-1. IMHO, 0/+1 makes more sense, and I believe it is the default way of doing things in MySQL as well. Not a huge problem, but if your checkboxes don't work, you should definitely check this.
One possible alternative would be to put the backend (with the data) on a shared drive. I remember this is well-documented, also in the help. You may want to have a look at some general advice on splitting into a frontend and a backend and code that automatically reconnects to the backend on startup; I can also send you some more sample code, or post it here.
Otherwise, you might also want to consider MS SQL. I don't have experience with that, but I presume it works together with MS Access much more nicely!
Gareth Simpson opined:
If it's only two users, then Access
should do just fine if you put the
.mdb on a shared drive.
Er, no. There is no multi-user Access application for which each user should not have a dedicated copy of the front end. That means each user should have an MDB on their workstation. Why? Because the objects in front ends do not share well (not nearly as well as Jet data tables, though there aren't any of those in this scenario using MySQL as the back end).
Gareth Simpson continued:
I believe the recommended max
concurrent users for Access is 5 but
on occasion I've pushed it past this
and never come unstuck.
No, this is completely incorrect. The theoretical limit for users of an MDB is 255. That's not realistic, of course, as once you reach about 20 users you have to program your Access app carefully to work well (though the things you need to do in an Access-to-Jet app are the same kinds of things you'd do to make any server database application efficient, e.g., retrieving the smallest usable data sets).
In this case, since each user should have an individual copy of the front-end MDB, the multi-user limits of Access/Jet are simply not relevant at all.
I know this doesn't answer your question directly, but it might be worth checking out the SQL Server 2005 migration tool for Access. I've never used the tool, but it might be worth using with SQL Server 2005 Express Edition to see if there are the same issues as you had with MySQL
Dont forget to put some type time/date stamp on each record. sometimes ms access will think "another user has changed or deleted the record" and will not allow you to make a change! I found this out the hard way.
In general, it depends :)
I haven't had a lot of problems when the application side has just been updating the data through the forms. You can get warnings/errors when the same row has been updated by more than one user; but Access seems to be constantly updating its live record sets all the time.
Problems can happen if Alice is already working with record 365, and the Bob updates it, and then Alice tries to update it with her changes. As I recall, Alice will get a cryptic error message. It would be easier for the users if you trap these errors and at least give them a friendlier error message.
I've had more problems when I was editing records in the VB code through RecordSets, especially when combined with editing the same data on forms. That's not necessarily a multi user problem; however, you have almost the same situation because you have one user with multiple connections to the same data.
If it's only two users, then Access should do just fine if you put the .mdb on a shared drive.
Have you tried it first rather than just assume it will be a problem.
I believe the recommended max concurrent users for Access is 5 but on occasion I've pushed it past this and never come unstuck.
On the other hand I did once use Access as the front end to MySQL in a single user environment (me). It was a singularly unpleasant experience, I can't imagine it would become nicer with two users.