We can create user in oracle 12c without c## but this is not recommended way. Oracle 12c has two kind of user called common user and local user. Still we can create oracle 12c user without c## by setting hidden parameter like below. SQL> select * from v$version; BANNER CON_ID ——————————————————————————– ———- Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 – 64bit Production 0 PL/SQL Release 12.1.0.2.0 – Production 0

CORE 12.1.0.2.0 Production TNS for 64-bit Windows: Version 12.1.0.2.0 – Production 0 NLSRTL Version 12.1.0.2.0 – Production SQL> create user orcldata identified by orcldata; create user orcldata identified by orcldata *

ERROR at line 1: ORA-65096: invalid common user or role name SQL> alter session set “_ORACLE_SCRIPT”=true; Session altered. SQL> create user orcldata identified by orcldata; User created.