error: ORA-65096: invalid common user or role name in oracle

99.9% of the time the error ORA-65096: invalid common user or role name means you are logged into the CDB when you should be logged into a PDB. For example, if you used the default 19c installation settings, you should login to ORCLPDB (the PDB) instead of ORCL (the CDB).

DANGER - If you insist on creating users the wrong way, follow the steps below.

Setting undocumented parameters like this (as indicated by the leading underscore) should only be done under the direction of Oracle Support. Changing such parameters without such guidance may invalidate your support contract. So do this at your own risk.

Specifically, if you set "_ORACLE_SCRIPT"=true, some data dictionary changes will be made with the column ORACLE_MAINTAINED set to 'Y'. Those users and objects will be incorrectly excluded from some DBA scripts. And they may be incorrectly included in some system scripts.

If you are OK with the above risks, and don't want to create common users the correct way, run this command before creating the user:

alter session set "_ORACLE_SCRIPT"=true;  

I found the answer here

I just installed oracle11g

ORA-65096: invalid common user or role name in oracle

No, you have installed Oracle 12c. That error could only be on 12c, and cannot be on 11g.

Always check your database version up to 4 decimal places:

SELECT banner FROM v$version WHERE ROWNUM = 1;

Oracle 12c multitenant container database has:

• a root container(CDB)
• and/or zero, one or many pluggable databases(PDB).

You must have created the database as a container database. While, you are trying to create user in the container, i.e. CDB$ROOT, however, you should create the user in the PLUGGABLE database.

You are not supposed to create application-related objects in the container, the container holds the metadata for the pluggable databases. You should use the pluggable database for you general database operations. Else, do not create it as container, and not use multi-tenancy. However, 12cR2 onward you cannot create a non-container database anyway.

And most probably, the sample schemas might have been already installed, you just need to unlock them in the pluggable database.

For example, if you created pluggable database as pdborcl:

sqlplus SYS/password@PDBORCL AS SYSDBASQL> ALTER USER scott ACCOUNT UNLOCK IDENTIFIED BY tiger;sqlplus scott/tiger@pdborclSQL> show user;USER is "SCOTT"

To show the PDBs and connect to a pluggable database from root container:

SQL> show con_nameCON_NAME------------------------------CDB$ROOTSQL> show pdbs    CON_ID CON_NAME                       OPEN MODE  RESTRICTED---------- ------------------------------ ---------- ----------         2 PDB$SEED                       READ ONLY  NO         3 ORCLPDB                        READ WRITE NOSQL> alter session set container = ORCLPDB;Session altered.SQL> show con_name;CON_NAME------------------------------ORCLPDB

I suggest read, Oracle 12c Post Installation Mandatory Steps

Note: Answers suggesting to use the _ORACLE_SCRIPT hidden parameter to set to true is dangerous in a production system and might also invalidate your support contract. Beware, without consulting Oracle support DO NOT use hidden parameters.

In Oracle 12c and above, we have two types of databases:

1. Container DataBase (CDB), and
2. Pluggable DataBase (PDB).

If you want to create an user, you have two possibilities:

1. You can create a "container user" aka "common user".
   Common users belong to CBDs as well as to current and future PDBs. It means they can perform operations in Container DBs or Pluggable DBs according to assigned privileges.

   create user c##username identified by password;

2. You can create a "pluggable user" aka "local user".
   Local users belong only to a single PDB. These users may be given administrative privileges, but only for that PDB inside which they exist. For that, you should connect to pluggable datable like that:

   alter session set container = nameofyourpluggabledatabase;

   and there, you can create user like usually:

   create user username identified by password;

Don't forget to specify the tablespace(s) to use, it can be useful during import/export of your DBs. See this for more information about it https://docs.oracle.com/database/121/SQLRF/statements_8003.htm#SQLRF01503