MDAC 2.5 SDK - OLE DB Programmer's Reference
Appendix C: OLE DB Properties

DBPROP_HIDDENCOLUMNS

Property group: Rowset

Property set: DBPROPSET_ROWSET

Type: VT_I4

Typical R/W: R

Description: Hidden Column Count

If DBPROP_UNIQUEROWS is VARIANT_TRUE, the DBPROP_HIDDENCOLUMNS property returns the number of additional "hidden" columns added by the provider to uniquely identify rows within the rowset. These columns are returned by IColumnsInfo::GetColumnsInfo and IColumnsRowset::GetColumnsRowset. However, they are not included in the count of rows returned by the pcColumns argument returned by IColumnsInfo::GetColumnsInfo.

To determine the total number of columns represented in the prgInfo structure returned by IColumnsInfo::GetColumnsInfo, including hidden columns, the consumer adds the value of DBPROP_HIDDENCOLUMNS to the count of columns returned from IColumnsInfo::GetColumnsInfo in pcColumns. If DBPROP_UNIQUEROWS is VARIANT_FALSE, DBPROP_HIDDENCOLUMNS is zero.