Synchronising Remote Databases

[helfire]

Overview:

I have constructed a DBMS, comprising of over 100 Filemaker Pro 5.5 databases managed via Filemaker Server v5.5. The purposes of the system is to be able to gather every single detail relating to a construction project of over 500 apartments and break it down to specific details relating to each wall, window, door etc. information relating to which is then applescripted into MiniCad for production of drawings. The client's LAN/WAN comprises of just Macs, at their offices, and an iMac in the construction site office which is connected via Remote Access to the main office.

Problem:

Being, after all, a construction site there are large power fluctuations close to the telephone lines, as well as a mainline overhead railway running close by to the site. We have experienced a large number of network connection failures, which results in the network connection to the site office being almost unusable.

After speaking with FMP support they suggested the answer might lie in using Filemaker Mobile to create a dialup to the site office and then run a synchronisation to/from an identical set of databases on the site office iMac. By timing the synch with, say, worker's lunch breaks it would be possible to have the server scripted to dial up the on-site iMac, perform the synch and then disconnect, as opposed to having to maintain a continuous open line.

My question is, before committing to more purchases, is this correct? Can Filemaker Mobile cope with the amount of data that would have to be synchronised - or is there a plug-in out there that will do this better?

Any help whatsoever would be vastly appreciated.

Julian Taylor

[Steven H. Blackwell]

I do not think FileMaker Mobile can be used in this fashion. Possibly FileMAker Pro can be. But what is the difference in making that connection and the one you are now using?

Old Advance Man

[Kurt Knippel]

Do you need to be moving around in all 500 units?

Filemaker Mobile could probably be used, but I think that you have a larger problem in exactly how you intend to gather and make use of the data on the construction site.

You might want to simply have a copy of Filemaker Pro on the iMac or a laptop along with a set of the databases and simple create the records and then export them to the server at lunchtime or whenever you can.

I would start by having a more detailed plan of what you are going to do, then look for ways to implement this plan.

[helfire]

Maybe I should have been a bit clearer.

The problem is synchronising data. This means that someone in the main office could enter all the details of one apartment, that information would then be made available to the site office. If someone in the site office then updates that information (information entered in the main office is from a plan, whereas the information entered from the site office is surveyed data) that information needs to synchronised back into the main office system. The system really only deals with one floor at a time, so the number of records/databases that would need to synchronised would be very small - about 2 records per database / and +/- 10 databases at a time.

[Vaughan]

Julian

The schronisation issue comes up every few months or so. The problem is always in the "rules" need to determine which edit to use if one record gets changed in two places: there is no way to "merge" such edits, and the rules always end up being arbitrary.

The general consenses seems to be this:

either: Create a set of very simple rules for synchronistion; understand and live with the consequences of lost changes, out-of-date data etc;

or: Get rid of the synchronisation forever by trashing all but one copy of the databases and getting people to connect remotely into this main system, so they are only ever updating and viewing the "master" data. FMP handles multiple users easily.

[helfire]

Thanks Vaughan.

What would happen then if, as an example, you had a number of sales agents in the field who,for ease of speed needed to access the host database on a daily basis, update their local database(s) and then disconnect. Given that a number of database systems have this ability I'm sure there must be some solution for doing this quickly and easily in Filemaker.

[Vaughan]

It's the "updating local databases" that is the hard part.

Example: two users both change record 111, each making different changes. When the time comes to "update" the system, which version of record 111 should go into the main system? Simple rules like "the last modified record" aren't going to work. What happens if one user deletes the record while another edits it -- which action should be taken then?

Now, if you make rules like "people can only change their own records" then synchronisation becomes much easier because multiple-edits are then not possible.

It's developing rules and ensuring they are followed (more correctly: cannot be broken) that is the key to successful synchronisation. It's not a technical difficulty once the rules are established.