SQL> SELECT sys.DBMS_ASSERT.simple_sql_name('1nvalid_name') FROM dual;
SELECT sys.DBMS_ASSERT.simple_sql_name('1nvalid_name') FROM dual
*
ERROR at line 1:
ORA-44003: invalid SQL name
ORA-06512: at "SYS.DBMS_ASSERT", line 146

--No links allowed

SQL> SELECT SYS.DBMS_ASSERT.SIMPLE_SQL_NAME('foo@bar') FROM DUAL;

SELECT SYS.DBMS_ASSERT.SIMPLE_SQL_NAME('foo@bar') FROM DUAL
*
ERROR at line 1:
ORA-44003: invalid SQL name
ORA-06512: at "SYS.DBMS_ASSERT", line 146

-- Valid Strings

SQL> SELECT sys.DBMS_ASSERT.simple_sql_name('valid_name') FROM dual;

SYS.DBMS_ASSERT.SIMPLE_SQL_NAME('VALID_NAME')
---------------------------------------------
valid_name

1 row selected.

SQL> SELECT sys.DBMS_ASSERT.simple_sql_name('"12 valid name"') FROM dual;

SYS.DBMS_ASSERT.SIMPLE_SQL_NAME('"12VALIDNAME"')
----------------------------------------------
"12 valid name"

1 row selected.