set autocommit on feedback on echo on
does display the comment, the dml result, and the commit result. In case of rollback, there is no message
SQL> CREATE TABLE T(X NUMBER PRIMARY KEY)
Table created.
SQL> ALTER TABLE T ADD CONSTRAINT C0 CHECK (X < 2) DEFERRABLE INITIALLY DEFERRED
Table altered.
SQL> SET AUTOCOMMIT ON
SQL> INSERT INTO T VALUES (1)
1 row created.
Commit complete.
SQL> UPDATE T SET X=2
1 row updated.
The error message
ORA-02091: transaction rolled back
ORA-02290: check constraint (SCOTT.C0) violated
is missing