[Zope] Detecting a NULL Value

[Dieter Maurer]

Asad Habib wrote at 2004-2-27 08:55 -0500:
>I have a field in my MySQL database which is allowed to be null and has a
>value of NULL as default. I am retrieving this field and numerous others
>using a call to dtml-in. After the retrieval, I would like to determine
>what this value is inside my DTML document/method. What is the equivalent
>of NULL in Zope? Is it a value of 'None'?
>
>I am using the following code but it doesn't work.
>
><dtml-if expr="undergraduate_projects_directed == 'None'">

Try: "..._directed is None".

-- 
Dieter