MDAC 2.5 SDK - OLE DB Providers
OLE DB Provider for ODBC

IUNKNOWN Data Type Conversions

Convert to type

Empty

IDISPATCH

NULL

VARIANT

Unsupported data type conversions

I1, I2, I4, I8, UI1, UI2, UI4, UI8, R4, R8, CY, NUMERIC, DECIMAL, DBTIME, DATE, DBDATE, DBTIMESTAMP, BOOL, BSTR, BYTES, ERROR, GUID, STR, WSTR