sqldatareader

[nooshin_bit]

سلام
sqldatareader چیست؟چه خاصیتی به متغییری که از این نوع تعریف می شه می ده؟؟

[mrhamidifar]

A DataReader is a read-only stream of data returned from the database as the query executes. It only contains one row of data in memory at a time and is restricted to navigating forward only in the results one record at a time. The DataReader does support access to multiple result sets, but only one at a time and in the order retrieved. Just as in the original version of ADO, the data is no longer available through the DataReader once the connection to the data source is closed, which means a DataReader requires a connection to the database throughout its usage. Output parameters or return values are only available through the DataReader once the connection is closed.

DataReaders all implement the same IDataReader interface, which means that all of the DataReaders should provide the same set of functionality. Each DataReader implementation is optimized for a specific data provider such as SQL Server or Oracle. Version 1.0 of the Microsoft .NET Framework includes a System.Data.SqlClient.SqlDataReader that is specific to SQL Server and a System.Data.OleDb.OleDbDataReader that is more generic for OLEDB providers. Version 1.1 of the .NET Framework introduced the SqlCeDataReader for connecting to the SQL Server edition for Windows CE, OdbcDataReader for ODBC data sources, and OracleDataReader for connecting to Oracle databases. It isn''t required that you use the DataReaders from Microsoft, and each database vendor often has its own .NET provider. In addition, you can implement a DataReader of your own through the IDataReader interface.