NOT NULL specification which means you must initialize it
SQL>
SQL> -- NOT NULL specification which means you must initialize it (otherwise, it gets the default value of NULL).
SQL>
SQL> set serverout on;
SQL>
SQL> DECLARE
2 X NUMBER NOT NULL := 20;
3
4 BEGIN
5
6
7 DBMS_OUTPUT.PUT_LINE(x);
8
9 END;
10
11
12 /
20