21.1 Comments/Troubleshooting

Most ADO.NET providers include a strongly typed DataReader . Every DataReader implements two interfaces: IDataReader (which defines the core reader functionality) and IDataRecord (which allows you to access the current record values). Because IDataReader extends IDataRecord, you can use the IDataReader to access all the IDataRecord and IDataReader functionality when writing provider-agnostic data access code.

Strongly typed DataReader objects typically add type-safe methods that allow you to retrieve column values as database-specific data types. Some DataReader classes for ADO.NET providers are shown in Table 21-1.

Table 21-1. Provider-specific DataReader classes

Class	Data source
System.Data.SqlClient.SqlDataReader	SQL Server
System.Data.OleDb.OleDbDataReader	An OLE DB provider
System.Data.Odbc.OdbcDataReader	An ODBC driver
System.Data.OleDb.OracleDataReader	Oracle