ACS3 Data Model

     1: function logical_negation(true_or_false IN varchar)
     2: return varchar
     3: is
     4: BEGIN
     5:   IF true_or_false is null THEN
     6:     return null;
     7:   ELSIF true_or_false = 'f' THEN
     8:     return 't';
     9:   ELSE
    10:     return 'f';
    11:   END IF;
    12: END logical_negation;