Differences between Oracle dba and sysdba

I used to mix dba and sysdba. Today I am discussing the differences between them in the Forum. The special record is as follows:

 

SYSDBA is not a permission. When a user logs on to the database as SYSDBA, the user will become SYS.

You can log on as sysdba to open the database, close the database, create SPFILE, and restore the database, which cannot be implemented by the DBA role;

Sysdba is the system permission and dba is the user object permission;

Sysdba manages oracle instances. Its existence does not depend on the full startup of the entire database. As long as the instance is started, it already exists;

Log on to the database as sysdba, load the database, and open the database. Only after the database is opened, or the whole database is fully started, the dba role has a foundation;

Dba is a set of role corresponding to the operation permissions of objects in the Oracle instance, while sysdba is a conceptual role that represents the identity during logon authentication. In addition, dba is an object in Oracle. Like Role and User, dba is a physical object that actually exists in Oracle. sysdba is a conceptual operation object, it does not exist in Oracle Data.