Update viewtable to handle null keyfield

lib/db-viewtable-html.lsp

@@ -68,8 +68,10 @@ end
 local reversekeyfields = {}
 if form.value.keyfields then
 	formvalues.fields = cfe({ type="group", value={} })
+	formvalues.nulls = cfe({ type="group", value={} })
 	for i,f in ipairs(form.value.keyfields.value) do
 		formvalues.fields.value[f] = cfe({ type="hidden" })
+		formvalues.nulls.value[f] = cfe({ type="hidden", value="false" })
 		reversekeyfields[f] = i
 	end
 end
@@ -92,7 +94,11 @@ allowupdate = allowupdate and viewlibrary.check_permission("updatetableentry")
 		<%
 		if formvalues.fields then
 			for i,f in ipairs(form.value.keyfields.value) do
-				formvalues.fields.value[f].value = tableentry[f]
+				if not tableentry[f] then
+					formvalues.nulls.value[f].value = "true"
+				else
+					formvalues.fields.value[f].value = tableentry[f]
+				end
 			end
 		end
 		%>