Why many tables ORACLE default 12c?

Creating a new database (basic and advanced), It's my first time dealing with Oracle, in which I do not know why so many tables, triggers, views and other objects when only wanted to create a relational data base empty.

Is there another way to do this or is there something I missed understand?

Thank you.

Capture:

Those objects are owned by SYS user. You could verify it using following query:

SELECT * FROM DBA_OBJECTS WHERE OWNER = 'SYS';

To see the objects owned by other users, see:

SELECT * FROM DBA_OBJECTS WHERE OWNER <> 'SYS';

You must have logged in as SYS AS SYSDBA, therefore able to view the objects owned by SYS user.

Remember,

• SYS/SYSDBA is special
• Never ever use SYS (or SYSDBA) for general database purpose, but for administration/maintenance purpose (startup, shutdown, backup, recover)
• SYS/SYSDBA is Oracle proprietary (try to open a SR/TAR starting with "i did that with SYS/SYSDBA" and you'll see the immediate answer)
• SYS/SYSDBA does not act like any other user
• When you use SYS/SYSDBA Oracle deactivates some code path and activates others
• Whatever you do with SYS/SYSDBA will neither validate nor invalidate the same thing with any other user.

NEVER EVER use SYS/SYSDBA for anything that can be done by another user. Use SYS/SYSDBA ONLY for something that can't be done by someone else.

See this answer on AskTom by Tom Kyte.