The System.Data.IDataReader and System.Data.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 the DataReader.

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

Classes that inherit System.Data.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, with alternative types in parentheses.

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

Namespace: System.Data
Assembly: System.Data (in System.Data.dll)
Assembly Versions: 1.0.3300.0, 1.0.5000.0, 2.0.0.0