Oracle Learning (16) users, roles, and permissions

First, users

1, the use of SQL to create the user's syntax format is as follows:

    Create user user_name--username/  
    [identified by password | externally | Globally as ' external_name ']--how to authenticate the user

, the authentication party There are 3 types: password, external and global,  
    --the password represents the use of the password provided by the user to authenticate, external representation of the use of Third-party programs to verify, such as

the operation of the system's login password, the global refers to when there is more than one data,  
    -to build a global user, Other databases are validated by this user and require keyword by*/only when using a password  
    [default tablespace tablespace_name]--Specify the user's defaults table space/  
    [temporary Tablespace Tablespace_name]--Specify the user's temporary tablespace/  
    [Quota integer K | integer M | Unlimited on Tablespace_name]--the maximum size that can be allocated in the specified table space

Space * *  
    [Profile Profile_name]--Specify profiles */  
    [default role RoleName,.. n | All[except rolename,... N] | None]--Specifies a user-owned role that defaults to assign

one or more default-roles to the user, All[except role is to assign  
    all roles or roles other than certain roles to the user, none to

specify no roles * *  
    [password expire]--means to invalidate the password, which will force the user to replace the password at the first login to the database/  
    [account Lock | unlock]--The accounts are locked or not.  
Sample code:  
    Create user Hello identified by the world password expire;

2, the use of SQL to modify the user's syntax format is as follows:

Alter user user_name  
identified by password | externally | Globally as ' external_name '
[default Tablespace TABLESP Ace_name]  
[temporary tablespace tablespace_name]  
[Quota integer K | integer M | unlimited on tablespace_name]
  
   [profile profile_name]  
[Default role RoleName | all[except rolename] | none]  
[password expire]  
[account Lock | Unlock]  
example code:  
alter user Hello identified by HelloWorld;
  

3, the use of SQL commands to delete the user's syntax format is as follows:

Drop user user_name [cascade]; --Using Cascade will remove the user-owned objects together with the * *  
example code:  
drop user Hello cascade;

Second, the role

1. The syntax format for creating roles using SQL statements is as follows:

Create role Role_name  
[not identified]  
[identified by password | externally | globally]

Sample code

Create role Hello;

2, the use of SQL statements to modify the role of the syntax format is as follows:

Alter role Role_name  
[not identified]  
[identified by password | externally | globally]

3, the use of SQL statements to remove the role of the syntax format is as follows

Drop role Role_name