Use Extended DB Types

[This is preliminary documentation and subject to change.]

DBPROP_USEEXTENDEDDBTYPES controls the data type of columns bound by OLE DB accessors.

If the value is VARIANT_TRUE, accessor column bindings can be based on PROPVARIANTs. By default, only OLE Automation VARIANTs and any directory binding are allowed for accessor column bindings.

Many commonly used properties are stored using types that are not OLE Automation VARIANTs. This causes considerable overhead in the OLE DB accessor used to retrieve the data, since the data must be coerced into a different type.

Clients that can make use of PROPVARIANTS should set DBPROP_USEEXTENDEDDBTYPES to VARIANT_TRUE and use OLE DB accessors with bindings that use PROPVARIANT types.