SQL assigns the DEFAULT defined for the column or domain. If no
    DEFAULT is defined, then NULL is assumed.

    If the DEFAULT clause is used in an UPDATE statement then one of
    the following will be applied:

    o  If a DEFAULT attribute is present for the column then that
       value will be applied during UPDATE.

    o  Else if an AUTOMATIC attribute is present for the column then
       that value will be applied during UPDATE. This can only happen
       if the SET FLAGS 'AUTO_OVERRIDE' is used since during normal
       processing these columns are read-only.

    o  Otherwise a NULL will be applied during UPDATE.