In this chapter, you'll get a broad view of the ADO.NET architecture and the basic building blocks of ADO.NET in a disconnected environment. This chapter plays a major role for later chapters as well. Actually, ADO.NET not only provides a way to work with databases, it also allows you to access various kinds of data sources and even in-memory representations of data. You'll learn how to write database applications without using a database. You'll also explore the System.Data and System.Data.Common namespace classes. Some of the common data objects covered in this chapter are DataTable, DataColumn, DataRow, and DataSet.