MySQL

First, both functions are used to process databases. First, mysqli connections are permanent connections, while MySQL does not. What does it mean? MySQL will re-open a new process whenever it is used for the second time, while mysqli only uses the

CopyCodeThe Code is as follows: select a. 'table _ scheme' as db_name, A. 'table _ name', A. 'table _ rows ', A. 'Engine' --, .* From Information_schema. 'tables 'a Left join information_schema. 'table _ constraints 'B On a. 'table _ name' = B. '

Show status Log on to MySQL directly under the command line to run the show status command. The query statement is as follows: The same statement also has show variables; and show status is used to view the MySQL running status, which is similar

MySQL storage engine MyISAM, InnoDB, and memoryMemory will be introduced later InnoDB supports transactions, foreign keys, and row locks. MySQL does not. InnoDB does not support Fulltext index types InnoDB does not save the specific number of

MySQL updates some data in the field in the first case: CopyCodeThe Code is as follows: Update tab set a = Concat (substring (A, 1, 3), 'bbb '); Start from 1 character of a and add 'bbb 'to A. If the original value of A is '123aaa', it is updated

The remote server can be accessed remotely. The problem I encountered was: There are three servers A, B, and C, and C is the server. B can use PHP to successfully connect to MySQL ON MACHINE C, while machine A cannot connect!It can be said that

Copy codeThe Code is as follows :#! /Usr/local/python Import OS Import time Import string Source = ['/var/www/html/xxx1/', '/var/www/html/xxx2/']Target_dir = '/backup /'Target = target_dir + time. strftime ('% Y % m % D ')Zip_comm = 'zip-r % s

1. php version Overview Differences between different php versions. The difference between VC6 and VC9, Thread Safe and Non-Thread Safe is generally found after php versions. VC6 is legacy Visual Studio 6 compiler, just It is compiled using this

After a large amount of data is deleted from your database, you may find that the size of the data file is not reduced. This is because fragments are left in the data file after the delete operation. Discuz! The data table optimization function is

-- Mysql ssl generates a key 1 check whether ssl is enabled Mysql> show variables like '% ssl % '; + --------------- + ---------- + | Variable_name | Value | + --------------- + ---------- + | Have_openssl | DISABLED | | Have_ssl | DISABLED | |

Example 1: stored procedure without Parameters Copy codeThe Code is as follows: $ conn = mysql_connect ('localhost', 'root', 'root') or die ("data connection Error !!! "); Mysql_select_db ('test', $ conn ); $ SQL =" Create procedure myproce () Begin

Preparation 1. configure the firewall and enable port 80 and port 3306.Vi/etc/sysconfig/iptables-A input-m state -- state NEW-m tcp-p tcp -- dport 80-j ACCEPT # Allow port 80 to pass the Firewall-A input-m state -- state NEW-m tcp-p tcp -- dport 3306

PHP programmers should know that they can use the mysql_pconnect (permanent connection) function to connect to the MySQL database. Using a permanent connection to the database can improve efficiency. However, in actual applications, permanent

Copy codeThe Code is as follows: #/bin/sh # Check whether mysql server provides services normallyMysqladmin-u sky-ppwd-h localhost ping # Obtain the Current Status values of mysqlMysqladmin-u sky-ppwd-h localhost status # Obtain the current

MySQL has multiple storage engines. MyISAM and InnoDB are two common storage engines. Here we will introduce some basic concepts about the two engines (not in depth ).MyISAM is the default storage engine of MySQL. Based on the traditional ISAM type,

How to restore a MYSQL backup The sample code uses PHP, which you are familiar with. Of course, you have read and understood the ideas in the sample code. I believe that you can quickly write the sample code in a language you are familiar. 1.

Copy codeThe Code is as follows: -- create a database Create table 'rate '( 'Uname' VARCHAR (300 ), 'Object' VARCHAR (300 ), 'Score 'varchar (300) ); -- Insert dataInsert into test. rate (uname, object, score)VALUES ('aaa', 'China', '67 '),('

Reference Table Count () is used to count the number of records Copy codeThe Code is as follows: mysql> select count (*) from score; Mysql> select count (*) from score where stu_id = 901; Sum () summation Function Copy codeThe Code is as follows:

The database inserts, updates, and deletes records in the table. InsertStatement to insert data UpdateStatement to update data DeleteStatement to delete data Reference Table Insert data without specifying the field name Insert field name not

The system information function is used to query the system information of the mysql database. VERSION () returns the database VERSION number. Copy codeThe Code is as follows: mysql> select version (); + ------------------------- + | VERSION () | + -