MySQL

Factors that affect slow SQL queries1, no index or invalid index caused by the full table scan.2. The amount of data and the number of tables associated with the table.Index is invalid1. When a table is associated with a query, the field type or

MySQL master-slave copy function principle 1, in the business complex system, there is a scenario, there is a SQL statement need to lock the table, resulting in the temporary inability to use the Read service, then it will affect the

ID: serial number; the actual priority, the higher the value, the higher the first is executed.--------------------------------------------------------------Select_typeThe type of SELECT statement can be in the following categories.Simple : The

1. Download the source package wget https://cdn.mysql.com//Downloads/MySQL-8.0/mysql-8.0.11.tar.gz2. Installation Kit Yum install-y cmake gcc gcc-c++ ncurses-devel ncurses 3. Unzip the source package TAR-ZXVF mysql-8.0.11.tar.gz4. Renaming the

This example uses a table task with the following structuremysql> desc Task;+-------------+------------+------+-----+-------------------+-------+| Field | Type | Null | Key | Default | Extra |+-------------+------------+------+-----+-----------------

Objective:One: What is an indexIndex is relative to the column that the data can be tableEach table has its own field and table data, field columns, and table data corresponds to one row of data in the tableThe index will change this field'sAll

In response to the company's needs, to create a more secure MySQL cluster, to achieve MySQL failover after the switch, the study of a few days finally have the results, share.First, introduce the function of this cluster scheme.1, MySQL server after

WHERE conditional clausesSyntax format:SELECT * FROM table name where condition;For example:Mysql> SELECT * from M1;+------+------+------+---------+| ID | name | Age | Address |+------+------+------+---------+| 001 |    L1 | 4 | Beijing || 002 |   L2

1) Download the installation package,version 5.7 needs to download a boost C + + 1.59.0, (slow download)#cd/data/soft# wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.21.tar.gz# tar-xfzf mysql-5.7.21.tar.gz# wget

When we use MySQL to import large file SQL, we may report the MySQL server has gone away error, the problem is that the default value of Max_allowed_packet configuration is too small, only need to increase the value of the key after the import again

Two ways to develop 1.using the VS bring-your-own visualizer is not recommended. Add a ' dataset ' to the VS project, then add the database as a data source through the visual tools, add SQL Server and Oracle by default, and require additional

Environment preparation Mysql-8.0.11-winx64.zip:https://cdn.mysql.com//downloads/mysql-8.0/mysql-8.0.11-winx64.zipInstallation environment: Windows7. Extract Unzip the Mysql-8.0.11-winx64.zip installation package to any directory (

1. Switch to the root userSu2. Installing Mysql-serverApt Install Mysql-serverNote: After Debian9, MySQL is replaced with mariadb.So after you type MySQL in terminal, the prompt you see is mariadb instead of MySQL:Login directly under Root, because

Common components of a relational databaseDatabases: DatabaseTables: TableRow: RowColumns: ColumnIndexes: IndexTrying to: viewUsers: UserPermissions: Privilege 存储过程：procedure 存储函数：function 触发器：

0. Introduction　　MySQL as a current mainstream open source relational database, has been widely concerned by everyone. Devc++ is also an open source, simple C + + editor that has a simpler and faster compilation than vs. But there are few links to

Host Operating System IP Address main software Master Centos7.3x64 192.168.200.132 MySQL 5.5.24 Slave1 Centos7.3x64 192.168.200.130 MySQL 5.5.24 Slave2

I. Database additions and deletions1. Create a new databaseCREATE database name CharSet UTF8;Database name rule: can be by letter, number, underscore, @, #, $ case-sensitive, cannot use keywords such as create SELECT, cannot use numbers alone,

First, download the corresponding version of the MySQL Zip package (for Windows) from the MySQL official webSecond, unzip the zip package into a custom folder (I put the e-drive, the path is E:\mysql-5.6.40-winx64)Third, enter the MySQL installation

Method 1:1. Stop the MySQL service# Kill ' Cat/var/run/mysqld/mysqld.pid 'Or# Pkill Mysqld2. Create a text file for a password assignment statement# VI Mysql-initALTER USER ' root ' @ ' localhost ' identified by ' mynewpass!6 ';Resets the password

SQL statements need to be compiled and executed, and stored procedures (Stored Procedure) are a set of SQL statements that are compiled in order to accomplish a particular function, stored in a database after compilation, and invoked by the user by