21. 1. 3. The slash character (/) at the end of the example executes the PL/SQL.
SQL>
SQL> SET ECHO ON
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
2 age NATURAL;
3
4 BEGIN
5 age := 10;
6 DBMS_OUTPUT.PUT_LINE('age:');
7 DBMS_OUTPUT.PUT_LINE(age);
8 END;
9 /
age:
10