MDAC 2.5 SDK - OLE DB Programmer's Reference
Appendix H: Data Type Conversion Interfaces
The OLE DB Data Conversion Library supports a limited set of conversions among OLE DB data types. For example, the DBTYPE_BYREF modifier is supported only on the destination type for variable-length data types (DBTYPE_BYTES, DBTYPE_STR, DBTYPE_VARNUMERIC, and DBTYPE_WSTR).
Note Supported data conversions can be determined through the CanConvert method of the IDataConvert interface.
Click an entry in the following table to see the supported data type conversions.
| Convert from data type: | |||
| I1 | I2 | I4 | I8 |
| UI1 | UI2 | UI4 | UI8 |
| R4 | R8 | BOOL | ERROR |
| BSTR | STR | WSTR | BYTES |
| DATE | DBDATE | DBTIME | DBTIMESTAMP |
| FILETIME | GUID | CY | DECIMAL |
| NUMERIC | VARNUMERIC | VARIANT | PROPVARIANT |
| IDispatch | IUnknown | ||