Re: Truth Tables for Oracle.

Hello !

To answer to your question, try this :

DECLARE
  t BOOLEAN := TRUE;
  f BOOLEAN := FALSE;
  n BOOLEAN;
  FUNCTION vb(x BOOLEAN) RETURN CHAR IS   BEGIN
    IF x IS NULL THEN RETURN ' N |';
    ELSIF x THEN RETURN ' T |';
    ELSE RETURN ' F |';
    END IF;
  END VB;
BEGIN

  DBMS_OUTPUT.PUT_LINE('AND | T | F | N |');
  DBMS_OUTPUT.PUT_LINE('. T |'||vb(t AND t)||vb(t AND f)||vb(t AND n));
  DBMS_OUTPUT.PUT_LINE('. F |'||vb(f AND t)||vb(f AND f)||vb(f AND n));
  DBMS_OUTPUT.PUT_LINE('. N |'||vb(n AND t)||vb(n AND f)||vb(n AND n));
  DBMS_OUTPUT.PUT_LINE('OR  | T | F | N |');
  DBMS_OUTPUT.PUT_LINE('. T |'||vb(t OR t)||vb(t OR f)||vb(t OR n));
  DBMS_OUTPUT.PUT_LINE('. F |'||vb(f OR t)||vb(f OR f)||vb(f OR n));
  DBMS_OUTPUT.PUT_LINE('. N |'||vb(n OR t)||vb(n OR f)||vb(n OR n));

It will give you the next truth tables :

AND | T | F | N |


. T     | T | F | N |


. F     | F | F | F |

OR | T | F | N |
. T | T | T | T |
. F | T | F | N |
. N | T | N | N |

(of course, T is True, F is False and N is NULL).

Hope this helps.

Bye
Pierre Received on Thu Dec 30 1999 - 06:24:14 CST