September 25, 2002 at 9:37 pm
Hi,
I'm looking at building a project with 100 salespeople on the road. I've read up on the SQL replication and all sounds pretty good so far.
I do have a question regarding data integrity however. If your mobile user is connected and transferring data to your central database, and the line drops out, does the replication engine handle this? Will it roll back for the next connection attempt, or will it "lose" data because of it? Or must you develop your own rollback and data integrity checks.
I'm looking for a very robust and reliable system. If anyone out there has had experience in this, I'd like to hear from you.
September 26, 2002 at 4:40 am
I haven't done this type of connection but the principal is like so. If the replication is interupted in mid point all changes will be rolled back. Only on successful finish are they commited and rolled forward. This is immediate with no regard to their state at the point of needing to roll back or forward.
"Don't roll your eyes at me. I will tape them in place." (Teacher on Boston Public)
September 26, 2002 at 6:01 am
Thats the nice part about using whats built in rather than coding your own, they've handled almost all of it. Going to use merge?
Andy
September 27, 2002 at 12:05 am
Yes, site autonomy is important in this scenario, so merge replication is very preferable.
I've found quite a bit on MSDE for use on mobile computers on the backend, which is great. However, I've been asked to look further down the track from swapping laptops to palm pilots etc, which certainly makes things interesting.
I've also been reading a bit about the SQLXML document creation capabilities within SQL 2000. Does MSDE also support this capability?
September 30, 2002 at 2:27 pm
I am also investigating use of replication for a remote sales force. The tests I have done so far suggest the opposite to Antares686 statement. My test publication includes 2 tables (order header and order lines). I set up a subscription and started synchronising. As the order headers were being synchronised I pulled the plug on the connection. My result - the order headers remained on the subscriber without any of their order lines. Is there a way of making the entire subscription synchronisation part of a transaction?
My fault - this was during the initial snapshot phase.
Edited by - carmines on 10/01/2002 2:04:46 PM
October 2, 2002 at 4:32 am
Thanks for the unpdate an info on what happens during intial snapshot. Does it follow what I stated with beyond that point.
Brendon. MSDE I am pretty sure does support SQLXML but I cannot find the info page on it. Also, for future consideration Palm does not support SQL server at this point but WinCE (PocketPC) does support SQL 2000 and I am pretty sure, replication.
"Don't roll your eyes at me. I will tape them in place." (Teacher on Boston Public)
October 2, 2002 at 6:32 am
CE supports merge replication if you install SQL CE, I've seen some demos that looked good. Only downside I saw is that changes are done at the row level, not column. Depends on your app whether its a big deal or not.
Andy
October 2, 2002 at 1:59 pm
Antares686. After further tests I can definately confirm your initial response (at least with respect to transactional replication). I am interested in the CommitBatchSize and CommitBatchThreshold arguments to the distribution agent because they suggest that transactions are committed during replication. For example, if 1000 transactions were made on a publisher the subscriber would perform a commit every 100 transactions. Does this suggest that if the line dropped after the first 100 transactions they would still be committed? I would be interested in your thoughts on this.
October 2, 2002 at 8:39 pm
I can confirm that MSDE supports XML coding same as SQL, which is good.
We're looking at alternatives to using replication (ie, XML) in order to ensure long life for the product. XML can provide some excellent ways of implementing B2B. Don't suppose anyone is using this yet in conjuction with mobile users?
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