What are Oracle administrator users?

SYS and SYSTEM are two accounts installed by default for each Oracle database. SYS mode is the owner of all internal database tables, structures, supply packages, processes, etc. It also has all V $ and data dictionary views, create all encapsulated database roles, such as DBA, CONNECT, and RESOURCE ). SYS is an Oracle administrator or root user. Because of its all-powerful nature, you should try to avoid registration to the system as SYS. When you register a job in the system with a SYS account, even a simple typing error may cause a devastating disaster.

Oracle administrator SYS is the only user who can access a specific internal data dictionary table because it has all the data dictionary structures. In order to explicitly authorize the data dictionary object to other modes, SYS is also the account you must log on. You must also use the SYS account when writing stored procedures or triggers using data dictionary views and tables. When the database is installed for the first time, the default password of the SYS account is CHANGEONINSTALL, And the password is changed immediately by every competent database system administrator.

The SYSTEM mode is also installed when the database is created. It is the default account used for DBA tasks. SYSTEM also has full permissions on all database objects, and many third-party tool software relies on the existence and privileges of the SYSTEM mode. The default password of SYSTEM, another administrator of the Oracle database, is MANAGER. Like the password of the SYS account, it should be changed immediately after the database is created. Many database SYSTEM administrators use SYSTEM mode to perform database management tasks, but it is more suitable for creating a special user to complete database administrator tasks, this ensures that a special account is connected to a specific person, and that specific user is responsible for all database modifications.

Because these modes are well known and exist in each Oracle database, it is important to change their default passwords immediately after the database is installed, this prevents unauthorized access to the account. If security is a major problem, you may also consider changing these accounts to non-Logon. You only need to set a valid password when logging on to them.

Note that you cannot register an account by issuing the ALTERUSER ×××identifiedbyvalues 'Password' command. 'Password' is a lowercase string. This sets the Stored Password as the actual value given for you, instead of the encryption method. In the encryption method, oracle uses a common ALTERUSER ××identifiedby 'Password' command to store passwords.

For Oracle, it is impossible to generate a lowercase encrypted password string, making login to this account impossible. The preceding section describes the Oracle administrator.

1. Procedure
2. Overall understanding of the Oracle System
3. Introduction to Oracle Architecture
4. Creation of OracleDB2 Stored Procedure
5. Demonstration of left-connected Oracle instances