SQL CE and Data Access

The .NET Compact Framework provides four ways to access a database from a compact device, as shown in the illustration above.

The top left box illustrates the simplest means: using ActiveSync to transfer a file containing XML data (which can be read and written with ADO.NET) from the device to a desktop PC. However, this simple model has significant limitations: it does not provide any method of reconciling changes should the device and the desktop application modify the same data, and it is only able to transfer data to a single PC.

Direct Database Access, shown in the top right box, allows the device to connect directly to a running instance of SQL Server using a two-tier, client/server architecture. The device application uses ADO.NET and the SQL CE provider to connect to SQL Server and retrieve or update data. This is easy for developers to implement and follows a design that is very familiar to developers. However, because each device connects directly to the SQL Server, it is not appropriate for applications where there may be large numbers of client devices and is more suitable for factory or shop floor scenarios.