ADO.NET Part II: The Disconnected Layer
The previous chapter gave you a chance to examine the connected layer and the foundational components of ADO.NET, which allow you to submit SQL statements to a database using the connection, command, and data reader objects of your data provider. In this chapter, you will learn about the disconnected layer of ADO.NET. Using this facet of ADO.NET lets you model database data in memory, within the calling tier, by leveraging numerous members of the System.Data namespace (most notably, DataSet, DataTable, DataRow, DataColumn, DataView, and DataRelation). By doing so, you can provide the illusion that the calling tier is continuously connected to an external data source; the reality is that the caller is operating on a local copy of relational data.