An rdoParameters collection contains all the rdoParameter objects of an rdoQuery object.
Remarks
The rdoParameters collection provides information only about marked parameters in an rdoQuery object or stored procedure. You can't append objects to or delete objects from the rdoParameters collection.
When the rdoParameters collection is first referenced, RDO and the ODBC interface parse the query searching for parameter markers – the question mark (?). For each marker found, RDO creates an rdoParameter object and places it in the rdoParameters collection. However, if the query cannot be compiled or otherwise processed, the rdoParameters collection is not created and your code will trigger a trappable error indicating that the object does not exist. In this case, check the query for improper syntax, permissions on underlying objects, and proper placement of parameter markers.