Questions about mysql, questions about MySQL

1,MySQL database is indeed free,People say it's sending 50M space,It's your ** running on someone else's server.,People give you.。

2, mysql is very simple, look at it will be managed, the creation of data is generally the first project to directly map the data into the database, no need to create manually.

3,**space,You won't use your own machine as a server, right?,Are you going to open it all day and all night? What domain name do you use? You should leave these troublesome problems to the ** business to solve!

First of all, the database is not free! What people send is what they give!

The database looks something like this:

database name; database username;

Password; To manage the database, you need to go into phpmyadmin management, usually in the control panel of your space (not the backend).

I created the database in my own space first. get the database name; database username; Password;

When installing the CMS program, it will prompt you to connect to the database! Fill in the corresponding amount, or you can use the PHP probe in your own space to test, upload the probe to your space directory, open your domain http: Your domain name The browser will appear in your probe window, fill in the database name, password, etc. in the mysql column below, and test the connection!

OK" is a success!

Summary. Dear, I'm glad to answer mysql's questions as follows: a table, which has id auto-increment primary key, when inserting 17 records, delete the 15th, 16th, 17th records, and then restart mysql, and then ins....

1) If the type of the table is myisam, then it is 18 because the myisam table will record the maximum ID of the auto-increment primary key into the data file, and restart the mysql auto-increment primary key. (2) If the type of the table is innodb, then the 15innodb table just records the maximum id of the auto-increment primary key into memory, so restart the database or opt the table

mysql.

Dear, I'm glad to answer mysql's questions as follows: a table, which has id auto-increment primary key, when inserting 17 records, delete the 15th, 16th, 17th records, and then restart mysql, and then ins....1) If the type of the table is myisam, then it is 18 because the myisam table will record the maximum ID of the auto-increment primary key into the data file, and restart the mysql auto-increment primary key.

(2) If the type of the table is innodb, then the 15innodb table just records the maximum id of the auto-increment primary key into memory, so restart the database or opt the table

What is the problem?

Pro, Microsoft Windows [version 10.] 1219](c) microsoft corporation。All rights reserved.

c: users dell>mysql -u root -penter password: Bankruptcy law regulations on executive salaries:

The salaries of directors, supervisors and senior managers of a bankrupt enterprise shall be calculated on the basis of the average wages of the employees of the enterprise.

What kind of question is that?

Where to start writing is c.

Dear, that's this Microsoft Windows [version 10.] 1219](c) microsoft corporation。All rights reserved.

c: \users \dell>mysql -u root -penter password:

Normally, MySQL queries are serial in PHP, but if the MySQL queries can be asynchronous, multiple SQL statements can be executed at the same time, which can greatly shorten the time of MySQL queries and improve the efficiency of database queries. Currently, asynchronous mysql queries are only available in the mysqli extension, and the query methods are as follows:

1. Use mysqli async mode to execute mysqli::query

2. Get the asynchronous query result: mysqli::reap async query

To use MySQL asynchronous query, you need to use MySQLND as the MySQL database driver for PHP.

If you use MySQL asynchronous query, you need to create a new connection for all queries, and the MySQL server will create a separate thread for each connection for processing. The principle of asynchronous MySQL in Swoole is to query through MySQLI Async mode, and then obtain the socket of the MySQL connection, add it to the EPOL event loop, and specify the function when the database returns the result, this process is completely asynchronous and non-blocking.

This should not be handled in SQL, but should be processed in display logic after extracting the data.