MySQL basics 3

1. understand mysql

2. Add new users
3. Modify user rights
4. Change user password
5. Query the user
6. Delete user

 

1. In essence, a database is a folder , Tables are files

  

 

 2. establish user   user1( new user )

 

create user 'user1'@'localhost' identified by '123456';

 

      Installed mysql There is 4 individual user user ,        user1 It's a new user

 

      Let's use this user link again

 

View the... Under this user     database （ only one ,rooot Initially, there are four databases under the user ）

 

3. Change user name   Or code  

 

Let's change the user name first

 rename user 'user1'@'localhost' to 'user2' @'localhost';

 

adopt mysql.user This table query mysql Users in   become use2 了

Changing the user's password  

alter user 'user2'@'localhost' identified by '654321';

 

Be careful After revising user2 After this user name and password , Log in and change your password 654321

 

4. Modify user rights , Log in root User's permission to modify other protection , Or modify the user's permission under the user

 

 

ps: Add permissions to users , Or after revoking the permission , Need to reopen cmd, link mysql Check the code effect

privileges: User permissions

* Yes select,update,indert,delete etc.   , If granted in full, you can use all

Refresh user rights flush privileges

grant privileges on database_name.table_name to 'user_name' @'host'

 

  for example :1

 grant all  on *.* to 'user1'@'localhost';   // The table is for the user user1 to grant authorization , Give Way user1 Give all library and table operations to this machine ,    It feels like root And user1 Users operate some libraries together

2.        grant select,insert on  cesi.student to 'user1'@'localhost';

// To the user use1 to grant authorization , Give Way user1 can cesi In the library student surface implement select Query and insert operations

The following is to revoke the permission of so and so user     Be careful (from)            Adding permissions is to

revoke  jurisdiction  on  Database name . Table name  from' user name '@' Host name '

privileges: User permissions

* Yes select,update,indert,delete etc.   , If granted in full, you can use all

 

 revoke all  on *.* from 'user1'@'localhost';    This cancels user1 User's operation authority on all databases , Except for the original one   

ps: all All permissions （ Additions and deletions ）      *.* Represents all libraries and tables

ps: Here is user1 user   There is no database that can be operated before revoking

5. Query the user

 

stay mysql Under the user , adopt mysql.user Table query  

select  user,host from mysql.user;

 

 6. Delete a user , It is not recommended to test root user , Delete... Here user2

 

  First log in to any user , operation ,  drop    user   'xxx user name '@' Host name '