Oracle (new user and user management)

Oracle Learning 1 (new user and user management) encountered an error that could not check the memory when installing oracle11g. I tried various methods on the Internet and did not solve the problem. I had no choice but to reinstall the system, change 32-bit to 64-bit to solve the problem. Some records of oracle commands under www.2cto.com I. Connection command: conn user name/password when connecting with a privileged user identity: followed by as sysoper disconnect: disc Change Password: passw, if you want to change the password of another user, you must use sys/system to log on. Display the current user name: show user disconnects from the database and exits SQL * plus exit; 2. Problems with new user management 1. The newly created user has no permissions, therefore, you cannot log on to the database by granting permissions to the Administrator. The command for creating a user is: create user username identified by password 2. permissions are divided into system permissions and object permissions. The system permissions are related to the user's permissions on the database (index creation, storage creation process, the object permission is the user's permission to operate on Data Objects of other users. (Data objects, such as tables, views, and processes) roles: (batch authorization of permissions) can be divided into two types: Custom roles and pre-defined roles. The conn role can log on to the database, and there are other permissions for dba resource. However, you can create a table in any tablespace. grant connect to user name connect is not a permission, instead, role 3. When you grant permissions to the newly created table, you can grant, view, modify, delete, and other permissions through sys, system, or a user with permissions, you can also grant permissions by using the grant all on table name to user name. Revoke revoking permissions revoke select on emp from yyj; 4. Users who maintain permissions can query a form at the same time, we also hope that the user can continue to pass this permission to other users. If it is the object permission grant select on emp to yyj with grant option, if it is the system permission system gives yyj permission: grant connect to yyj with admin optionyyj can pass the connect permission down. 3. The user manages www.2cto.com. 1. The user locks the account. The user can enter the maximum number of logon attempts, or specify the lock time, generally, this command is executed as a dba. System create profile file (create rule) create profile lock_account (name) limitfailed_login_attempts 3 (number of attempts allowed) password_lock_time 2 (number of locked days, cannot log on within these days ); assign the rule to the user alter user Username profile rule name 2. unlock the user alter user Username account unlock; 3. Terminate the password so that the user can regularly change the password create profile rule name limit password_life_time 10 (how many days to change) password_grace_time 2 (grace period of 2 days ); alter user Username profile rule name 4. Password History: when you change the password, you can use the password history instead of the previous one, in this way, oracle stores the password modification information in the data dictionary, so that when the user changes the password, oracle will compare the old and new passwords with the create profile rule name limit password_lift_time 10 password_grace_time 2 password_reuse_time 10 (unavailable for the second input, but can be used after 10 days) 5. Delete the profile drop profile rule name (cascade)