MySQL

Today formally began a long road, I intend to spend the last few years to brush mysql5.5 source code, because the books at hand are basically based on mysql5.5, so there is no 5.7 version of the code, not to mention I am more concerned about the

Workaround:⑴ Open the My.ini in MySQL (if not, copy the My-default.ini and modify it to My.ini);⑵ in [mysqld] below the blank line directly add skip-grant-tables;⑶ restart MySQL, enter MySQL on the cmd page and press ENTER.Note: This will make your

MySQL foreign key creation condition:1. Two tables must be a INNODB data engine2. Foreign key field of foreign key table must be primary key3. Field types must be consistentCreate a foreign key when creating a table:CREATE TABLE Tbl_client (userName

1. OverviewWhen we consider the highly available architecture of the MySQL database, we mainly consider the following aspects: If the database is down or an unexpected outage, and so on, can restore the availability of the database as soon

Type Size Describe Char[length] Length byte Fixed-length field, 0-255 bytes long Varchar[length] String length + 1 bytes The variable length field, before mysql5.03, has a length of 0-255

1. Common SQL statements1) Common functions/*The value of type

When installing MySQL, if the character encoding is the default value latin1, you need to modify it to UTF8 to support Chinese data.The command is as follows:1. Display the database character set Mysql> Show create DATABASE test;+----------+

1. Select the most applicable field propertiesMySQL is good at supporting large data volumes, but in general, the smaller the tables in the database, the faster queries are executed on it. Therefore, in order to achieve better performance when

In the process of using MySQL, there are some questions about the concepts of MyISAM and InnoDB, and the difference between the two engines has always been a question in my mind. In order to solve this puzzle, search the network, found the following

Scene demo:mysql> CREATE TABLE test (ID int,name varchar (), primary key (ID)); Query OK, 0 rows affected (0.04 sec) mysql> insert into test values (1, ' TTT '); Query OK, 1 row Affected (0.00 sec) mysql> INSERT INTO test values (2, ' TTT '); Query

--A and B two table data is consistentSelect CustomFrom A left join B on a.id = b.IDwhere b.id is nullNote: The result of this query is that there is data in table A and no in table BSelect CustomFrom B left join A on a.id = b.IDwhere a.id is

MySQL User management and Rights management--Operating environmentMysql> Show variables like ' version ';+---------------+--------+| variable_name | Value |+---------------+--------+| Version | 5.6.25 |+---------------+--------+1 row in Set (0.04

MysqlslapThe MYSQLSLAP can simulate the load on the server and output timing information. It is included in the MySQL 5.1 release package and should be available in MySQL 4.1 or later. The number of concurrent connections can be executed at test

One, MySQL query for five seed sentences:1,where (conditional query), commonly used operators:① comparison Operators>, =, ② logical operatorslogical non: not/! , logical OR: OR/| | , logic with: and/&&③ fuzzy query "like"Wildcard:% any character,

Mysql inserts data into sub-tables, and mysql inserts data Use mysql;/* Create the original data table */Drop table if exists 'articleinfo ';Create table 'articleinfo '('Id' bigint unsigned not null AUTO_INCREMENT primary key,'Title' VARCHAR (20)

MySQL query prompt and MySQL prompt   MySQL query prompt:1. LOW_PROPRITY, HIGHT_PRIORITYPurpose: Specify the running priority of SQL statements. The SQL statements with the HIGHT_PROPRITY prompt are scheduled to the beginning of the Table Access

Graph tutorial on installing and configuring mysql 5.7.13 on Mac, mysql5.7.13 The installation tutorial for mysql 5.7.13 on Mac is detailed. The record is as follows: First, download the installation package from Baidu mysql. In this case, the

MySQL-group-replication configuration steps (recommended), groupreplication MySQL-Group-Replication is a new feature developed by the mysql-5.7.17 version; it achieves strong consistency between master-slave, However, for the moment, the performance

Mysql GTID Mha configuration method, mysqlgtidmha Configuration Gtid + Mha + Binlog server Configuration: 1: Test Environment OS: CentOS 6.5Mysql: 5.6.28Mha 0.56 192.168.1.21 mysql1 M1192.168.1.22 mysql2 S1192.168.1.23 mysql3 S2 Mha manage, Binlog

Optimization Methods when Mysql consumes too much CPU (mandatory). mysql is mandatory. When the CPU usage of Mysql is too high, which aspects should we optimize? If the CPU usage is too high, consider the following: 1) In general, to eliminate high