ADO.NET in a Nutshell

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

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