On Wednesday morning Steve Lasker delivered his second public webcast (the first is available for viewing here) on the up and coming Microsoft Sync Services. For anyone who has worked with sql mobile, now sql server ce again, one of the biggest issues is how to replicate data between a central server. Whilst there are all sorts of ways that a custom solution can be written (for example datasets across webservices or an Xml blob via a raw http request) there are current two mechanisma that are built into the platform to support syncing with sql server, RDA and Merge replication. RDA is essentially a client configurable set of queries that can be used to pull down a specific set, or subset, of the server data. Merge replication is a server configurable publication to which the client can subscribe. Both of these mechanisms work via an IIS virtual directory making it possible to sync across the web. This also leads itself quite nicely to securing the data as SSL can simply be applied to the webserver.
There are significant limitations to both RDA and Merge. Which is where MSS comes into play. Instead of being just a client or server technology, MSS appears to have both client and server code that is written by the application developer to control how the sync process behaves. This includes whether the sync will be done directly (which would be the preference on a LAN) or indirectly (ie via a webservice proxy). It also includes hooks so that the application can handle conflicts and get access to updates before they are applied. This looks an exciting product and I can’t wait to see the CTPs.
Also, it is worth pointing out that a fellow MVP, Bill Vaughn, has released his first eBook on SQL Server CE. Check it out at http://www.hitchhikerguides.net/EBooks/Titles/default.aspx