ASP.NET in a Nutshell

Reading Data

There are two basic techniques for reading data in ADO.NET: using data readers and datasets. Additionally, data may be read from either a backend DBMS, such as SQL Server, or from a simple (or complex) XML file. In the next several sections, we’ll discuss these techniques and data sources.

Reading from a Database

The following sections describe the use of data readers and datasets, provide an example, and discuss why one would use one technique over the other.

Using a data reader

The data reader technique consists of using an instance of either the SqlDataReader or OleDbDataReader class to retrieve the data in a similar fashion to a forward-only, read-only database cursor. Data readers provide lightweight access to data that is recommended when retrieving data for display in a Web Forms page or for other circumstances in which the overhead of a dataset is not desirable.

About the Examples

For the sake of simplicity and consistency, all examples in this chapter that access data from a DBMS use the Pubs sample database in the NetSDK named instance of the Microsoft Data Engine (MSDE). MSDE is a slimmed-down version of SQL Server that fills a role that is similar to Microsoft Access for desktop applications. The NetSDK instance may be installed along with the .NET Framework SDK samples, after installing either the .NET Framework SDK or Visual Studio .NET.

All examples in this chapter use trusted connections rather than pass a user ID and password as part of the connection ...