Using DAO to manipulate NULL values in record sets in C++

Question

I'm trying to access a record set containing null values using the methods described in:

http://msdn.microsoft.com/en-us/library/ff965871.aspx

I'm using DAO in particular and it works, except when you return a result from an access query like:

SELECT MAX(ID) FROM [TABLE] WHERE KEY = SOMETHING NOT THERE

This returns a record set with 1 record that contains a null value, and trying to access it using record set pointer functions:

rsp->getitem(0)

works but

rsp->getitem(0)->getvalue()

throws a strange exception that I can't find online. I'm wondering if anyone knows how to handle NULL values in C++, functions that work in VBA like "IS NULL" don't seem to be available.

Answer 1

getvalue should return variant type and you may check vt property of returned value. Most likely if nothing returned it will be VT_NULL.