Limit the field that are syncronized

Question

Hi

I'm building an application that runs on a Windows Mobile device. I'm using Microsoft's Sync Framework to sync the Sql CE database with the main corporate db.

The question is how can I limit the fields that are syncronized? The table in question has stacks of fields but I only need to display a few of them on the mobile device and replication is only one way (from the server to the mobile) so that shouldn't be an issue. I've seen this similar question but there's not much info there. Can anyone give me more advice on how to achieve this? I imagine that it's a very common requirement.

Also, does anyone know if I can use the Sync Framework Version 2.0 or do I have to stick to 1.0. I had a feeling that 2.0 doesn't support Windows Mobile but I'm not sure.

Cheers
Mark

Answer 1

You can change the T-SQL that's generated behind the scenes to not include all the columns of the table, but there are a couple of gotchas here. Firstly, it means that you can't use a wizard to modify the sync selection later - not a big deal, and creating your own partial class to override just the specific method with the T-SQL for your table mitigates that a bit.

Second, changes to the unincluded (not sure if that's a word?) columns can also trigger a download of that row as by default the change tracking is by row. You can change this by setting the Track_Columns_Updated flag

ALTER TABLE Employee
ENABLE CHANGE_TRACKING
WITH (TRACK_COLUMNS_UPDATED = ON)

Depending on the number of rows and size of the data and frequency updated, I have often found an easier solution is to provide a trigger on the main table of the server to update records in a separate table containing just the data you need, then sync that. It makes it much easier to change what's downloaded later. This is obviously not a solution if you are downloading the entire works of Shakespeare, but for a few 1000 records of a product catalogue, I think it's perfectly feasible.