Restricting the use of the database (1 Viewer)

[aziz rasul]

I want to give an MS Access db to someone who can use the db in no more than 3 machines. How can I achieve this?
I have created a table in which the motherboard serial number is inputed when the db is used in a new machine.

 

[theDBguy]

You could do a DCount() of the MB serial number table (could be one approach).

 

[aziz rasul]

But if the end user copies the db to say 3 different machines from the first copy of the db, he\she would effectively have a Dcount value of 1 i.e. the first MB serial number and therefore end up potentially having more than 3 copies of the db, if you see what I mean?

 

[theDBguy]

But if the end user copies the db to say 3 different machines from the first copy of the db, he\she would effectively have a Dcount value of 1 i.e. the first MB serial number and therefore end up potentially having more than 3 copies of the db, if you see what I mean?

If you put the serial number table in the BE, they would all have the same number of records. So, copying the original FE won't help. Copying the original BE will mean they have to start over with their data.

 

[The_Doc_Man]

The problem is simple. You can't do this easily, if at all, using Access by itself. But if you allow for a brief human intervention, you have a shot.

Don't sell him a 3-machine license. Sell him 3 single-machine licenses. We have some articles on how to program such licenses in Access. Then tell him that he has to identify the three machines on which he will use the software. You take whatever he sends as machine identification, use it to generate some sort of hash key, and you are good to go.

Here is at least one thread on this topic:

Validation Key for DB - hash email and exp date

Hello, I'm totally new to trying to figure this out, I've read lots but quite confused! I've made a db that I want to add a licence key to so that the db shuts down unless a valid licence key is entered by the user. It doesn't need to be totally secure and if people go to the lengths to hack...

www.access-programmers.co.uk

NOTE: Unless you sold him the right to modify the DB, this is a case where you might wish to look at building an .ACCDE file. IF you sell this person the right to modify the DB (customize, if you prefer that language), then you cannot restrict usage at all, since in that case your customer would simply strip out the restriction code.

 

[aziz rasul]

theDBGuy, surely the end user would simply copy over the BE as well.

The_Doc_Man, I didn't think on those lines. I will have a look at the link.

 

[theDBguy]

theDBGuy, surely the end user would simply copy over the BE as well.

And like I said, that would mean, they'll be starting over. Also, I said it's just one approach. Without knowing all your concerns and intentions, it's hard to give you an advice that covers all of them.

 

[aziz rasul]

OK, no worries, I'm looking at the link that The_Doc_Man has given to see whether there is something there I can glean.

 

[theDBguy]

OK, no worries, I'm looking at the link that The_Doc_Man has given to see whether there is something there I can glean.

Right, there's lots of other approaches, but they usually apply to a specific scenario. For example, I use a "web lookup" to make sure they have a legit copy of the db. No web connection, no entry. No valid license, no entry. etc.

 

[aziz rasul]

Hmmm, good idea. I need to look into that as a possiblility as well. Thanks.
My son is a web expert, so he may be able to help me on that.

 

[isladogs]

I use a different approach to the same problem.
Clients can purchase a license for e.g. 3 or 5 workstations (etc).

The licence agreement specifies that they are permitted to install it on as many workstations as they wish BUT that code is used to check the number of concurrent users.
So if they have a 3 user licence, the first 3 users can login successfully but anyone trying to login after that is blocked (with a suitable info message) ...until someone else logs out.

That approach is simpler to code and works well.
It has the side benefit of possibly encouraging clients to purchase additional licenses if necessary

 

[aziz rasul]

That approach is simpler to code and works well.

Is that something you have done?

 

[isladogs]

Yes I have in one of my commercial apps UK Postal Address Finder.
However, before you ask, I'm not going to give away the code in case that helps anyone to crack the app security I have used

 

[aziz rasul]

No problem.