logged on as sysdba, how to run dml script as another user if you do not have the passwrod
If you really need to log in as that user, use a proxy user:

SQL&gt; conn / as sysdba
Connected.
SQL&gt; select count(*) from dba_users where username = 'UNKNOWN_PASSWORD';

  COUNT(*)
----------
         1

SQL&gt; conn UNKNOWN_PASSWORD/UNKNOWN_PASSWORD
ERROR:
ORA-01017: invalid username/password; logon denied


Warning: You are no longer connected to ORACLE.
SQL&gt; conn / as sysdba
Connected.
SQL&gt; create user proxy_user identified by proxy_password;

User created.

SQL&gt; alter user UNKNOWN_PASSWORD grant connect through proxy_user;

User altered.

SQL&gt; conn proxy_user[UNKNOWN_PASSWORD]/proxy_password
Connected.
SQL&gt; show user
USER is "UNKNOWN_PASSWORD"
SQL&gt;


Otherwise, you can run DML on objects in other schemas.