[Zope] Authorization error with for missing values ??

[Brian Hooper]

Hi!

I've been trying to use DateTime values with ZSybaseDA, and have come
across the following strange behavior:

I'm doing a query to my database to get out data which includes a
datetime field which can in some cases be NULL.  (The field name is
'birthdate'; let's call the table, for the example, 'User').

I have a Z SQL Method selectUsers which does something like:

select * from User

which is referenced from a DTML Document like this:

<dtml-in selectUsers>
  <dtml-var birthdate>
</dtml-in>

This works fine if none of the birthdates are NULL; however if birthdate
is NULL, then I get an authorization dialog, even though I am already
logged into Zope as a Manager in the top-level acl_users folder.  The
only way to get past the authentication dialog is to log in as the Zope
superuser.

What's going on here?  I traced code to RDB.py, where it looks like
Missing.MV should be substituted for any values which don't come back in
the query results for a given field.  The test() method of the
selectUsers Z SQL Method handles things OK, but I don't seem to have
permission to look at Missing.MV in a regular document...

--Brian