SQL>
SQL> declare
2 myNumber_constant constant number;
3 begin
4 null;
5 end;
6 /
myNumber_constant constant number;
*
ERROR at line 2:
ORA-06550: line 2, column 5:
PLS-00322: declaration of a constant 'MYNUMBER_CONSTANT' must contain an initialization assignment
ORA-06550: line 2, column 23:
PL/SQL: Item ignored
SQL>