Pluggable Databases

I had installed my Oracle 12c database. Then I logged into Enterprise Manager with the SYSTEM account. I tried creating a user. This is what I got back:
SQL Error
Error signaled by database server
ORA-65096: invalid common user or role name
ORA-06512: at "SYS.PRVTEMX_ADMIN", line 8565
ORA-06512: at "SYS.WRI$_REPT_SECURITY", line 288
ORA-06512: at "SYS.DBMS_REPORT", line 898
ORA-06512: at line 1
What? At first I thought something was broken with user creation. Then I paid closer attention to the ORA-65096. Okay. I need a more complicated username. Nope. That was not the problem. Finally I broke down and Googled the subject.

Apparently there is some new magic going on with Oracle 12c. The username needs to start with C##. I should have known something was up when the default username in Enterprise Manager when you create a new user is C##.

This has something to do with the Oracle 12c multitenant architecture. That is somehow connected to pluggable databases as well. Those are not terms I am familiar with yet. I did see online that there were some hacks I could apply that would let me name usernames the way I want. Time to get hacking.