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IDataRecord Interface

Provides access to the column values within each row for a DataReader, and is implemented by .NET Framework data providers that access relational databases.

Namespace: System.Data
Assembly: System.Data (in system.data.dll)

public interface IDataRecord
public interface IDataRecord
public interface IDataRecord

The IDataReader and IDataRecord interfaces enable an inheriting class to implement a DataReader class. This provides a way of reading one or more forward-only streams of result sets. For more information about DataReader classes, see Retrieving Data Using a DataReader. For more information about how to implement .NET Framework data providers, see Implementing a .NET Framework Data Provider.

An application does not create an instance of the IDataRecord interface directly, but creates an instance of a class that inherits IDataRecord. Typically, you do this by obtaining a DataReader through the ExecuteReader method of the Command object.

Classes that inherit IDataRecord must implement all inherited members, and typically define additional members to add provider-specific functionality.

Providers implementing a DataReader are required to expose data in common language runtime (CLR) types. Type coercion is defined for some types not included in the CLR. These values may be accessed as alternative types that comply with CLR types. As an example, the following table lists suggested mappings from OLE DB data types to CLR types, and lists alternative types in parentheses in the CLR Type column.

OLE DB Type

CLR Type

DBTYPE_BOOL

Int16

DBTYPE_BSTR

string

DBTYPE_BYTES

byte[]

DBTYPE_CY

Decimal

DBTYPE_DATE

DateTime

DBTYPE_DBDATE

DateTime

DBTYPE_DBTIME

DateTime

DBTYPE_DBTIMESTAMP

DateTime

DBTYPE_DECIMAL

Decimal

DBTYPE_EMPTY

null

DBTYPE_ERROR

ExternalException

DBTYPE_FILETIME

DateTime

DBTYPE_GUID

Guid

DBTYPE_HCHAPTER

not supported

DBTYPE_I1

SByte

DBTYPE_I2

Int16

DBTYPE_I4

Int32

DBTYPE_I8

Int64

DBTYPE_IDISPATCH

object

DBTYPE_IUNKNOWN

object

DBTYPE_NULL

DBNull.Value

DBTYPE_NUMERIC

Decimal

DBTYPE_PROPVARIANT

object

DBTYPE_R4

Single

DBTYPE_R8

Double

DBTYPE_STR

string

DBTYPE_UDT

not supported

DBTYPE_UI1

byte (Int16)

DBTYPE_UI2

UInt16 (Int32)

DBTYPE_UI4

UInt32 (Int64)

DBTYPE_UI8

UInt64 (Decimal)

DBTYPE_VARIANT

object

DBTYPE_VARNUMERIC

not supported

DBTYPE_WSTR

string

The following example creates instances of the derived classes, SqlConnection, SqlCommand, and SqlDataReader. The example reads through the data, writing it out to the console. Finally, the example closes the SqlDataReader, and then the SqlConnection.

private static void ReadOrderData(string connectionString)
{
    string queryString =
        "SELECT OrderID, CustomerID FROM dbo.Orders;";

    using (SqlConnection connection =
               new SqlConnection(connectionString))
    {
        SqlCommand command =
            new SqlCommand(queryString, connection);
        connection.Open();

        SqlDataReader reader = command.ExecuteReader();

        // Call Read before accessing data.
        while (reader.Read())
        {
            Console.WriteLine(String.Format("{0, {1",
                reader[0], reader[1]));
        

        // Call Close when done reading.
        reader.Close();
    


Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

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