ORA-01442

This was tested on Oracle 11.2. If you define a column as NOT NULL then try to modify it to NOT NULL again, you get an ORA-01442:

SQL> create table tab1 (col1 number not null)

  2  /

 

Table created.

 

SQL> alter table tab1 modify (col1 number not null)

  2  /

alter table tab1 modify (col1 number not null)

                         *

ERROR at line 1:

ORA-01442: column to be modified to NOT NULL is

already NOT NULL

 

SQL>