Form Builder simple question

Using Oracle 9i Forms Builder I am trying to write a trigger which will disallow changes to a STAFF table at the weekend. So far, I have:

BEGIN

DECLARE

BEGIN

if TO_CHAR(SysDate, 'DY') = 'SAT' or
TO_CHAR(SysDate, 'DY') = 'SUN' THEN

MESSAGE('Updates not allowed on weekends.');

end if;

END;

END;

What code do I need so that any text boxes relating to the STAFF table on my form will be dynamically set to disabled if it the weekend?

Any help much appreciated

Here is few examples:

For every single column
SET_ITEM_PROPERTY(item_name, ENABLED, PROPERTY_FALSE);

For any entire block:
SET_BLOCK_PROPERTY(block_name,INSERT_ALLOWED,FALSE);
SET_BLOCK_PROPERTY(block_name,UPDATE_ALLOWED,FALSE);