Using Excel as front end to Access database (with VBA)

Question

I'm sure you'll get a ton of "don't do this" answers, and I must say, there is good reason. This isn't an ideal solution....

That being said, I've gone down this road (and similar ones) before, mostly because the job specified it as a hard requirement and I couldn't talk around it.

Here are a few things to consider with this:

How easy is it to link to Access from Excel using ADO / DAO? Is it quite limited in terms of functionality or can I get creative?

It's fairly straitforward. You're more limited than you would be doing things using other tools, since VBA and Excel forms is a bit more limiting than most full programming languages, but there isn't anything that will be a show stopper. It works - sometimes its a bit ugly, but it does work. In my last company, I often had to do this - and occasionally was pulling data from Access and Oracle via VBA in Excel.

Do I pay a performance penalty (vs.using forms in Access as the UI)?

My experience is that there is definitely a perf. penalty in doing this. I never cared (in my use case, things were small enough that it was reasonable), but going Excel<->Access is a lot slower than just working in Access directly. Part of it depends on what you want to do....

In my case, the thing that seemed to be the absolute slowest (and most painful) was trying to fill in Excel spreadsheets based on Access data. This wasn't fun, and was often very slow. If you have to go down this road, make sure to do everything with Excel hidden/invisible, or the redrawing will absolutely kill you.

Assuming that the database will always be updated using ADO / DAO commands from within Excel VBA, does that mean I can have multiple Excel users using that one single Access database and not run into any concurrency issues etc.?

You're pretty much using Excel as a client - the same way you would use a WinForms application or any other tool. The ADO/DAO clients for Access are pretty good, so you probably won't run into any concurrency issues.

That being said, Access does NOT scale well. This works great if you have 2 or 3 (or even 10) users. If you are going to have 100, you'll probably run into problems. Also, I tended to find that Access needed regular maintenance in order to not have corruption issues. Regular backups of the Access DB are a must. Compacting the access database on a regular basis will help prevent database corruption, in my experience.

Any other things I should be aware of?

You're doing this the hard way. Using Excel to hit Access is going to be a lot more work than just using Access directly.

I'd recommend looking into the Access VBA API - most of it is the same as Excel, so you'll have a small learning curve. The parts that are different just make this easier. You'll also have all of the advantages of Access reporting and Forms, which are much more data-oriented than the ones in Excel. The reporting can be great for things like this, and having the Macros and Reports will make life easier in the long run. If the user's going to be using forms to manage everything, doing the forms in Access will be very, very similar to doing them in Excel, and will look nearly identical, but will make everything faster and smoother.

I do this all the time. If you're using ADO, you're not really using Access, but Jet, the underlying database. That means anybody with Excel can use the app - Access not required. Oh I should mention, the place I work bought a bunch of Office Small Business licenses - no Access. Prior to working here, I would have assumed that anyone who had Excel would also have Access. Not so.

I create one class for every table in Access. I very rarely run queries through ADO, instead I keep that logic in the class modules. I read in with a SELECT statement and write out with and UPDATE or INSERT using the Execute method of the ADODB.Connection object.

See http://www.dailydoseofexcel.com/archives/2008/12/21/vba-framework-ii/

if you want to see how I set up my code.

To answer your questions: It will be a small learning curve for you if you already know Excel VBA, but there will be some learning to do; you will pay a performance penalty over doing it all in Access, but it's not that bad and only you can decide if it's worth it; and you can have multiple people accessing the database.

Just skip the excel part - the excel user forms are just a poor man's version of the way more robust Access forms. Also Access VBA is identical to Excel VBA - you just have to learn Access' object model. With a simple application you won't need to write much VBA anyways because in Access you can wire things together quite easily.

If the end user has Access, it might be easier to develop the whole thing in Access. Access has some WYSIWYG form design tools built-in.

Unless there is a strong advantage to running your user form in Excel then I would go with a 100% Access solution that would export the reports and data to Excel on an ad-hoc basis.

From what you describe, Access seems the stronger contender as it is built for working with data:
you would have a lot more tools at your disposal to solve any data problems than have to go around the limitations of Excel and shoehorn it into becoming Access...

As for your questions:

1. Very easy. There have been some other questions on SO on that subject.
   See for instance this one and that one.

2. Don't know, but I would guess that there could be a small penalty.
   The biggest difficulty I see is trying to get all the functionalities that Access gives you and re-creating some of these in Excel.

3. Yes, you can have multiple Excel users and a single Access database.
   Here again, using Access as a front-end and keeping the data in a linked Access database on your network would make more sense and it's easy as pie, there's even a wizard in Access to help you do that: it's just 1 click away.

Really, as most other people have said, take a tiny bit of time to get acquainted with Access, it will save you a lot of time and trouble.
You may know Excel better but if you've gone 80% of the way already if you know VBA and are familiar with the Office object model.

Other advantages of doing it in Access: the Access 2007 runtime is free, meaning that if you were to deploy to app to 1 or 30 PC it would cost you the same: nothing.
You only need one full version of Access for your development work (the Runtime doesn't have the designers).