Professional Visual Studio® 2008

26.1. Occasionally Connected Applications

An occasionally connected application is one that can continue to operate regardless of connectivity status. There are a number of different ways to access data when the application is offline. Passive systems simply cache data that is accessed from the server, so that when the connection is lost at least a subset of the information is available. Unfortunately, this strategy means that a very limited set of data is available and is really only suitable for scenarios where there is an unstable or unreliable connection, rather than completely disconnected applications. In the latter case, an active system that synchronizes data to the local system is required. The Microsoft Synchronization Services for ADO.NET (Sync Services) is a synchronization framework that dramatically simplifies the problem of synchronizing data from any server to the local system.

26.1.1. Server Direct

To get familiar with the Sync Services, we will use a simple database that consists of a single table that tracks customers. You can create this using the Server Explorer within Visual Studio 2008. Right-click the Data Connections node and select Create New SQL Server Database from the shortcut menu. Figure 26-1 shows the Create New SQL Server Database dialog in which you can specify a server and a name for the new database.

Figure 26.1. Figure 26-1

When you click ...