In this chapter you've explored the support in the Compact Framework for working with data locally on the device. This has included the support for working with file, XML, and relational data programmatically and persisting the data to the device, as well as the support for data binding in Compact Framework forms. Together these make up the first essential architectural concept. However, most applications run in occasionally connected or connected modes and, so, must query and retrieve data from remote data sources. In the next chapter you'll explore the ways in which this can be done in the Compact Framework.