MySQL

Objective A few days to take a time to "high-performance MySQL" looked at the index is very important, and then summed up to consolidate knowledge. This article uses the InnoDB storage engine as an index. Because this article does not say that the

First, the database master-slave replication Basic requirements:1、操作系统版本一致（建议）。2、数据库版本一致（建议）。3、配置文件参数一致（是指一些性能参数）。Second, network topologyIII. Primary Database configuration file[mysqld]user = mysqlbasedir = /app/mysqldatadir = /app/mysql/dataport=33

First, the database master-slave replication Basic requirements:1、操作系统版本一致（建议）。2、数据库版本一致（建议）。3、配置文件参数一致（是指一些性能参数）。Second, network topologyIII. Primary Database configuration file[mysqld]user = mysqlbasedir = /app/mysqldatadir = /app/mysql/dataport=33

log in and exit MySQLMysql-h-p-u-P-E-H Specify Host name-P Specify MySQL server port-U Specify user name-P means login password-e-Connect SQL statementsCreate user1.create user wing;Create user [email protected] ' localhost ' identified by ' 12345 ';

One, MySQL data type The type of data field defined in MySQL is important for database optimizationMySQL supports multiple types and can be broadly divided into three categories: numeric, DateTime, and string (character) types Second,

First, the approximate operation procedureEnvironment Introduction:Os:center OS6.5mysql:5.6 version　　1. Turn off the firewallView firewall Status: Service iptables status　　　　This means that it is not closed.Run the following command to turn off

1. Statement: SELECT @rownum: [email protected]+1 as rownum, orderstate.*From (SELECT @rownum: =0) R, Orderstate;Execution Result:2. Revelation: Through this operation I am more aware that the view is the use of SQL queries using similar outer joins,

MySQL concurrency update common scenarios optimistic lockselect * from tab1 where id = ?;update tab1 set col1 = ? where id = ? and version = ?; Disadvantages May fail to update under high concurrency, so need to retry

1 SQL991.1 SQL99 syntaxSelect Query List from [ connection Type ] Join on join condition where filter condition; Connection type: Internal connection: Inner External connection: Left Outer connection: outer Right

Tools/Materials Windows operating system MySQL Database Method/Step 1Use the Win+r shortcut key to open the DOS command window and locate the bin directory under the MySQL installation directory, such as D:\Program

1. Operation of the database remember to add a semicolon [;] End CREATE DATABASE [DB name]; Drop databse [database name];use [database name]; Select Database//2. The Operation//field name of the data table is ID, name, age these ...//unsigned

First, the installation method1.msi2.zipHere we use the MSI bar, just practice words, a lot simplerSecond, MSI installation1. Click on the installation file and click Next on the Installation Wizard that appears.　　　　2. Agree to the MySQL User

System Database :INFORMATION_SCHEMA: Virtual library, mainly stores the information of some database objects in the system, such as user table information, column information, permission information, character information, etc.Informance_schema:

1, uninstall mariadb, or install MySQL will appear conflict2. Add the official Yum sourceTake CENTOS7 installation mysql5.6 as an example:Create and edit a Mysql-community.repo fileVi/etc/yum.repos.d/mysql-community.repoPaste the following in and

INT (m), M is the tube of what use?As an extension to the Ansi/iso SQL92 standard, MySQL also supports the integer types TINYINT, Mediumint, and BIGINT listed in the table above. Another extension is that MySQL supports arbitrarily specifying a

1. Change the root passwordMysqladmin-uroot password ' yourpassword '2. Remote Login to MySQL serverMysql-uroot-p-h192.168.137.10-p33063. Querying the Databaseshow databases;4. Enter a databaseUse DatabaseName;5. List the tables in the databaseShow

The syntax for the aggregation operation is as follows:--SELECT [field1,field2,...... fieldn] Fun_name-From TableName--[WHERE where_contition]--[GROUP by Field1,field2,...... fieldn--[with ROLLUP]]--[Having where_contition]--The following

Redo log (redo log)Preface: The difference between the bin log and the InnoDB log file in MySQL has been unclear, and there is always a question in the mind binlog log files can be used forLog backups of the database have been restored, and a redo

1 Basic INTRODUCTION to constraint 1.1 constraints A restriction that restricts the data in the table to ensure accuracy and reliability in the table. 1.2 Classification of constraints NOT NULL: non-null constraint.

A comprehensive technology for MySQL optimization, mainly includingA: Rationalization of table Design (3NF compliant)B: Add appropriate index (index) [Four kinds: normal index, primary key index, unique index unique, full-text index]C: Sub-table