[Zope] SQL Problem

[Philip Beardmore]

I'm having a really annoying SQL problem which I think (or hope) can
easily be sorted but I'm not sure how to do it.

I have a ZPT which is collecting data in a form - Both text boxes and
checkboxes.  The form then passes the variables on to a DTML Method
which does a few bits of error checking then calls an Z SQL Method to
insert the data.

If all of the data is completed (i.e. each textbox and checkbox is
ticked) then the form inserts the data exactly as it should.  If not all
checkboxes are ticked the page returns an error - This is due to the SQL
Method trying to insert data which hasnt been passed to it.

Below is my SQL Method:

INSERT choices
(userid, datetime, course, name, core1, core2, core3, core4, core5,
choice1, choice2, choice3, choice4)
VALUES
(
<dtml-sqlvar userid type=string>,
<dtml-sqlvar datetime type=string>,
<dtml-sqlvar course type=string>,
<dtml-sqlvar name type=string>,
<dtml-sqlvar core1 type=string>,
<dtml-sqlvar core2 type=string>,
<dtml-sqlvar core3 type=string>,
<dtml-sqlvar core4 type=string>,
<dtml-sqlvar core5 type=string>,
<dtml-sqlvar choice1 type=string optional>,
<dtml-sqlvar choice2 type=string optional>,
<dtml-sqlvar choice3 type=string optional>,
<dtml-sqlvar choice4 type=string optional>
)

Arguments are:
userid datetime course name core1 core2 core3 core4 core5 choice1
choice2 choice3 choice4

Note: Choice1-4 are checkboxes and every other item is a textbox.

Please help - Its doing my head in!

Cheers and all the best
Phil