Synchronisation in Microsoft Access

[jack1080]

Please consider the situation below:
There is a central server and there are many client PCs connected to the server. On each client PC, there is an access database file that will be frequently updated by the user of the PC.

What I want to do is to allow the user on each of the client PC to backup their database file to the central server;

At the server side, it is free to use any architecture(eg using file system or another database to store the file) to facilitate the backup purposes. One of simplest solution is to upload the entire database file to the central server everytime. However, the problem is the access database file on each client PC is quite big, hence it is better not to upload the entire file but only to upload the updated data to the central server.

Is there a way to synchronise the data with central server without upload the entire database file? What kind of architecture should built up in the central server if there is a way?

Any input is welcome

 

[fneily]

How many users? You can just place the database on the server and have everyone access one database.
You can split the database into FrontEnd(FE) and BackEnd(BE). Two files are created. One contains the tables(data) the other has their queries, forms, reports. So each user has a file to retrieve data and only one place to update/add data. Any basic Access book can show you this.
Or create a Master database and then replicas. Then on a schedule, you can sync them. Again, see any Access book.

For more info on these ideas, search the Access forums.

 

[jack1080]

Let me input some more details. Each of the database that used by each of the users is not relevant to each other. Each user has their own database file. Those users has used the database for quite awhile, and we should not change the schema of their database. To upload and download the data from the server is a new requirement.
Hence as passionh mentioned, there should be some login mechanism for each of the users.

There is two button at the access form, which marked as "upload data" and "download data". The user communicates with the server via the internet. When they upload the data, the server side data will be overriden with the data they uploaded. When they download the file, their PC data will be overridden by the database data.

But since the user connect to the remote server via dial up modem, it is very slow to uploaded and downloaded their entire database file to and from the server, since their file size is about 50MB. But most of the capacity is occupied by the access form, not the data itself. It only has about 10 tables with not much data.

I am thinking of, to extract the data part of the mdb file, make it as a new mdb file with much more smaller file size, and upload to the server. Is it possible?

For the replication, I have considered about it. But it includes the changes to the user database they are using currently.

By the way, it needs to support about 20,000 users.

 

[Hap007]

Hi Jack1080,

Sounds like you need a seperate application to do the upload and download. Currently, if you try to make the application upload or download itself, you will be attempting to copy an existing open file and that will not work.

I might suggest a small standalone application that first zips the desired database and then sends the database (zipped copy) via ftp or an email with an attachment.

I have done this in the past, and it works fine, although never for the number of users(20,000) like you mention.

You would probably want to buy an ftp utility.

Hope this Helps,
Hap...

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