.Net Framework Essentials

Content Components

Content components encapsulate data. In previous ADO versions, the Recordset object represented such a component. The data contained by the recordset component is in the form of a table, consisting of columns and rows. In ADO.NET, the data encapsulated by the DataSet component is in the form of a relational database, consisting of tables and relationships. This is a major improvement in data-access technology. In this section, we provide a high-level survey of the core classes that make up the content components, including DataSet, DataTable, DataColumn, DataRow, DataView, and DataRelation.^[35]

DataSet

If you are familiar with ADO, you know that data transfers between components are a recordset . The recordset contains data in a tabular form. Whether the recordset includes information from one or many tables in the database, the data is still returned in the form of rows and columns as if they were from a single table. ADO.NET allows for more than just a recordset to be shared between application components. This is one of the most important features of ADO.NET: we will be transferring a DataSet instead of a recordset.

The DataSet can be viewed as an in-memory view of the database. It can contain multiple DataTable and DataRelation objects. With previous versions of ADO, the closest you could get to this functionality was to exchange data with a chain of Recordset objects. When the client application receives this chained recordset, it can get to each of the ...