Network security class assignment

One , take all Change it to select jurisdiction , And will * . * Change to specified database

1 create user [email protected] identified by ‘123456’; Create a password for haha123 The local haha user
2 grant select on test.* to ‘xixi’@‘localhost’; Use grant to grant authorization
3 show grants for [email protected]; see haha Authority
Two ,page16k It is amended as follows 8kb：

1, First check the size of the current page ：mysql> SHOW GLOBAL STATUS like ‘Innodb_page_size’;

2, Modify the page size source code ：vim /mysql-5.5.25/storage/innobase/include/univ.i
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3,mysql> SHOW GLOBAL STATUS like ‘Innodb_page_size’;

3、 ... and 、N Fork tree N Whether it can be modified manually

​ You can modify
Method ：
1、 By changing key Value to adjust
N The non leaf nodes in the fork tree store index information , The index contains Key and Point The pointer .Point The pointer is fixed to 6 Bytes , If Key by 10 Bytes , So a single index is 16 Bytes . If B + The page size in the tree is 16 K, So a page can store 1024 An index , here N Is equal to 1024. We change Key Size , You can change N Value .
2、 Change the size of the page
The larger the page is , The more indexes a page holds ,N The greater the .
After the data page is adjusted , If the data page is too small, the number of layers will be too deep , The data page is too large , The time to load into memory and the time to query a single data page will increase , It needs to be balanced .
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Four ,Truncate and delect difference

The same thing ： These two are being deleted table All data in the table can be deleted , While preserving the table structure .
Difference ：
Truncate table ; Once you do this , Clear all table data . meanwhile , Data cannot be rolled back .
Delect form： Once you do this , All table data can be cleared . At the same time, data can be rolled back .

5、 ... and ,substr and substring What's the difference?

Difference ：
Substr： The second parameter intercepts the length of the string （ Intercept a certain length of characters from the starting point ）;
Substring： The second parameter is to intercept the final subscript of the string （ Intercept 2 String between positions , With head and no tail ）\

6、 ... and ,MySQL Storage and trigger procedures ：
stored procedure ：
1, Create format ：create proceduce 111
2, Contains more than one code , Code block use begin and end Between
3, Create a separator in the command line demlimiter

trigger

1, Create trigger using create trigger Trigger Name .

2, When to trigger ？
after insert on users, Handle after also before , Is before operating on the table (before) Or later (after) Trigger action .

3, What action event triggers ？
After insert on users, The operation time includes insert,update,delete

4, What table triggers ？
after insert on users

5, Scope of impact ？
For each row

trigger ： And functions 、 Like stored procedures , A trigger is an object , It can operate events according to the table , Trigger some actions , These actions can be insert,update,delete And so on .

7、 ... and , Strict patterns lead to mysql5.7 Failed to create user , How to solve

modify my.ini(Windows System ) or my.conf(Linux System ) The configuration file , With linux Take the system as an example ：sql-mode=STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
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Modified into ：
sql-mode=NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
And then restart mysql service
service mysql restart