We upload sales transactions from our stores to the headoffice server. At the moment, we use DTS (SQL Server Data Transformation Services), but we’re planning on replacing that with Microsoft Sync services for ADO.NET, as this seems to be Microsoft’s preferred solution for this type of setup and we want to follow the standard (that will be hopefully be around for a long time). Here are the details of our setup and what we’re planning. I’m looking for some advice, especially about whether Sync Services fits into our solution.
Situation
Each store has a 3rd party EPOS system which stores sales in a Microsoft Access 2000 database, which we can access. Our headoffice database is SQL Server 2005, but will be upgraded to 2008. The headoffice is not on a VPN with all the stores, but we can open up our firewall to the stores’ IP addresses, so that they can send data directly to SQL Server. The stores are always connected to the internet via ADSL, although they do lose connection and we don’t want to lose sales data. We are only uploading transactions from the store – definitions do not need to be downloaded.
Current solution
We have written a Windows service that runs on the store PC. This service downloads a DTS package from the server (which contains all the details of the upload) and runs it in the store – and this will upload sales to our server. We chose DTS, because it is free when you install MSDE. We can’t use SSIS, because that would require a SQL Server licence at every store. Another reason we chose DTS is that the details of the upload (i.e. which tables and fields to include) are stored on our headoffice server, so if we need to change things we can do that centrally and don’t need to install anything new at the stores. This isn’t a showstopper, but would be nice to have this ability in our new solution.
Potential solution - Microsoft Sync services for ADO.NET
We are currently building a proof of concept with Microsoft Sync services for ADO.NET. The idea is to put SQL CE (SQL Server Compact 3.5) in each store (client) and sync that to the headoffice SQL Server 2005 database (server). We’ll get the data into the SQL CE database either by (1) syncing it with the Access 2000 database or (2) getting the EPOS system developers to write sales straight into the SQL CE database – probably (2). But our main concern is getting the data from the store to the headoffice server. This method seems to be Microsoft’s preferred solution for occasionally connected systems and that is what made us look seriously at Sync Services. I’m hoping that using this will mean that most of the work needed to upload the sales will be built into Sync Services and we won’t have to re-invent the wheel.
Potential solution - Upload to a custom webservice
There is also the possibility of uploading the sales transactions to a custom web service on our headoffice server and then into our SQL Server database. This means that we will have to build our own mechanism for determining which rows are new, and as well as caching for when the systems are disconnected. Also, we might be missing out on other functionality that will come built into Sync Services.
Please let me know if you have any advice that will help, especially : “Is Sync services the right solution!”. The problem that we are trying to solve seems very generic (uploading sales from stores) – and I’d like to solve it with a generic solution.