Companion script for PL/SQL 101: Why can't I display a Boolean value with DBMS_OUTPUT.PUT_LINE?

View All Scripts Login to Run Script

Script Name Companion script for PL/SQL 101: Why can't I display a Boolean value with DBMS_OUTPUT.PUT_LINE?
Description Quick demonstration of ability of DBMS_OUTPUT.PUT_LINE to display strings, numbers and dates, but not Booleans. Used in: http://stevenfeuersteinonplsql.blogspot.com/2016/11/plsql-101-why-cant-i-display-boolean.html
Area PL/SQL General
Contributor Steven Feuerstein
Created Tuesday November 01, 2016

Statement 1

BEGIN
   DBMS_OUTPUT.put_line ('abc');
   DBMS_OUTPUT.put_line (DATE '2016-10-31');
   DBMS_OUTPUT.put_line (TO_CHAR (SYSDATE, 'YYYY-MM-DD HH24:MI:SS'));
   DBMS_OUTPUT.put_line (123456.789);
END;

abc
31-OCT-16
2016-11-01 09:17:53
123456.789

Statement 2

BEGIN
   DBMS_OUTPUT.put_line (TRUE);
END;

ORA-06550: line 2, column 4:
PLS-00306: wrong number or types of arguments in call to 'PUT_LINE'
ORA-06550: line 2, column 4:
PL/SQL: Statement ignored

More Details: https://docs.oracle.com/error-help/db/ora-06550

Statement 3

DECLARE
   my_boolean BOOLEAN := FALSE;
BEGIN
   IF my_boolean
   THEN
      DBMS_OUTPUT.PUT_LINE ('TRUE');
   ELSIF NOT my_boolean
   THEN
      DBMS_OUTPUT.PUT_LINE ('FALSE');
   ELSE
      DBMS_OUTPUT.PUT_LINE ('NULL');
   END IF;
END;

FALSE

Additional Information

Database on OTN SQL and PL/SQL Discussion forums
Oracle Database
Download Oracle Database