Synchronizing a database

[DCS]

I am using FMP6 on three computers. Two are connected together as peer to peer, the third is a laptop that can connect to the powerstation/server via wireless. I am looking for a script that can synchronize my laptop with the server when the laptop is taken out of range of the wireless, had data added, then brought back in range of the wireless. I want to be able to import/export new data from the laptop and put it on the server and take new data from the server and import/export it to the laptop. Can this be done and if so, how? I contacted a local FMP person who says he thinks it is not possible. I SURE HOPE HE IS WRONG!!

[Kurt Knippel]

Well, this is "possible", but I am not sure that you are ready to bear the cost of developing this kind of synchronization.

How often will you be doing this? Is once a day enough, once a week, once when your return from a road trip?

What kind of synchronization are you looking for? Every change made in each system synchronized? Just new records synchronized? Desktop systems synchronized with the laptop?

Synchronization in not easy and it is not generally cheap, but it certainly is possible.

[DCS]

We will be synchronizing the laptop with the server anywhere from once a day to 10 times a day. We just want new data that has been put on the laptop; (new records only) transfered to the server and new data put on the server transfered to the laptop; (new records since the last synch with the laptop only). We will only be synchronizing FMP6; (we have around 15 files with around 5000 records in each one) that will need to be synchronized; (again only exhcanging new info, not all 5000 records each time). I am pretty new to this, so I hope I am explaining this properly. I was under the impression that FMP could do this through the import/export feature, but that we had to somehow mark a field so FMP could see which records were already present and which records were new, thus preventing the import/export of old records. The bottom line is that we want to be able to write a report using FMP6 on the laptop and also write a report using the power station/server, then have them exchange the new info with each other when we link them up.

[Vaughan]

Filemaker can do it, sure. It's the logic behind the synchronisation that's difficult.

Example: the remote user adds three new records, edits record #1234 and deletes #3332. On the main system another user edits record #3332 and deleted #1234.

It's easy to see that the three new records can be added into the main system, but what happens to the deleted records? Won't the user who edited #1234 be annoyed!

The trick is to constrain what changes can be made. You've already gone a long way down the road by stating that only new records in each system get synchronised. This is relatively easy to implement.

It's cases where records are edited and deleted that the rules become complicated. There are no easy answers.

The only other complication I can think of is if the records have serial numbers: say check or invoice numbers. It's possible that new records on the remote system could have the same numbers as records made on the local system since they cannot communicate between themselves to know that the number is no longer available.

For a relational system where unique ids are required there are ways of creating keys that are almost guaranteed unique (do a search on the Forums for "unique keys"). It'll be for things like cheque or invoice numbers where it'll become difficult.

[DCS]

Well, You bring good news, in the sense that it can be done. The laptop doesn't really need to be able to edit old records, only implement new ones and add them to the database. I guess now I am looking for the right person to tell me how. Do you know where I can get someone to write this script, or at least lead me through how to do it. Again, I appreciate your help regarding this matter.

[Jay G.]

Good points by Kurt and Vaughn. Another solution you should look at is SyncDeK.

SyncDeK 4.5 enables secure, robust two-way synchronization between multiple mobile users and/or FileMaker Servers:

http://www.syncdek.com/

Unlike FileMaker Pro's simple import "merge" feature, SyncDeK

[DCS]

Going to give Snycdec a try. I really appreciate everyone's help on this matter. I hope it works. Thank you.

Chris