Why does ORACLEsqlplus/assysdba successfully log on?

Open and run. Type "sqlplusassysdba" without entering any user name and password. Why can I log on successfully? Run the "showuser" command to query whether the current logon user is a sys user or enter "sqlplusaaabbbassysdba". The logon is successful !!! Why? 1. Because oracle users log on using external

Open and run. Type "sqlplus/as sysdba" without entering any user name and password. Why can I log on successfully? Run the "show user" command to check whether the current logon user is a sys user or enter sqlplus aaa/bbb as sysdba !!! Why? 1. Because oracle users log on using external

Open and run. Type "sqlplus/as sysdba" without entering any user name and password. Why can I log on successfully?

Run the command: show user;

Query the current logon User: sys user

You can also enter sqlplus aaa/bbb as sysdba to log on !!!

Why?

1. oracle user logon uses an external authentication method, that is, as long as you can log on to the computer operating system normally, you can log on successfully without entering any user name or password. That is, you can log on to the database as a super administrator. So this is why we can view the logged-on user sys. This is an external authentication method (also known as operating system verification). During verification, oracle reads the database configuration file sqlnet. ora, which is the file to be verified and read during oracle login. The file is located at: D: \ oracle \ product \ 10.2.0 \ db_1 \ network \ ADMIN \ sqlnet. ora, SQLNET. AUTHENTICATION_SERVICES = (CNT). The parameter value is: the operating system authentication method is specified.

2. If you do not enter the username and password, the system automatically creates an operating system database administrator group "ora_dba" when installing oracle ", to successfully log on, add the current operating system user to the ora_dba group.

There are three logon methods for ORACLE:

1. operating system authentication (external authentication)

2. Password Authentication

3. All Certifications

Here we only talk about operating system authentication. The other two types of authentication can be viewed on the Internet by yourself.