MySQL

MySQL Multi-instanceOverview: Running multiple database services on a single physical hostFunction: Save operation and maintenance cost, improve hardware utilizationConfiguration Step DescriptionWe take mysql-5.7.20 as an example--Install packages

1. View slave statusshow slave status\G2, stop slave State, clear the master-slave information from the librarystop slave；reset slave all;3. Deleted from library synchronized main library databaseDROP DATATBASE DBNAME;4. Backing up primary database

MySQL in Myisam,innodb by default is the Btree index, as to how the data structure of btree is not important,Only need to know the result, since is the index that this data structure finally is orderly, like Xinhua dictionary His directory is

A brief introduction: Today let's talk about some problems in the slow query logTwo phenomena: Slow log appear some slow SQL, slow log appear slow SQL is not strange, strange is slow log take out itself is the second level execution, not slowThree

A constraint is a restriction that ensures the integrity and uniqueness of a table's data by restricting the data on the table's Rows or columnsConstraint classification:Constraint types and keywords: Primary KEY PRIMARY Key Default

1.mysql and Promise-mysqlNodejs connection MySQL has a mature npm package MySQL, if required promise, recommended to use Promise-mysql;Npm:https://www.npmjs.com/package/mysqlHttps://www.npmjs.com/package/promised-mysqlIn the actual development, the

1. Configure PHP.iniVi/etc/php.ini2. Configure ApacheMake a backup of the files you need to configure firstCp/etc/httpd/conf/httpd.conf/etc/httpd/conf/httpd.conf.bakAfter editing the configuration vi/etc/httpd/conf/httpd.conf configuration is

There are two ways to fully backup MySQL: Packaging a folder backup with tarInstalling the XZ compression Format tool: Yum–y install XZPackage The database folder: Tar jcvf/opt/mysql-$ (date +%f). tar.xz/usr/local/mysql/data/ Backing up

MySQL is not like Oracle has plsqldevelper tools to debug stored procedures, so there are several simple ways to track the execution process: 1, with a temporary table, recording debugging process; 2, directly in the stored procedure, add select XXX,

auto_increment Questions:Https://yq.aliyun.com/articles/59263?spm=5176.8091938.0.0.bjzoFNHttps://dev.mysql.com/doc/refman/5.7/en/innodb-auto-increment-handling.htmlSeveral situations that cause auto_increment to become smaller:Reference:

MySQL Database Development Learning Tutorial one, database designDatabase design (i)--Database designhttp://blog.51cto.com/9291927/2087925Second, MySQL database development Basic TutorialThe basic MySQL database development Tutorial directory is as

MySQL (default data table Myisam&inonodb)Can be set in MySQL config file My.ini, the book is written in Default-table-type. But not found in the My.ini, but# The default storage engine that would be used when create new tables

First, the operation of the table1. View all TablesShow tables;2. Create a tableCREATE TABLE table name (field 1 type 1 constraint 1, field 2 type 2 constraint 2);3, modify the name of the tableRename table name to the new name;4. Delete a

MySQL is not sensitive to trailing spaces73530589Conclusion: It is recommended to trim the string in the query condition, preferably trim when the data is in storage.Example1:The field values in the table do not have spaces, where the query

Non-null constraintCREATE TABLE USER ( INTnotNULL,-- non-null constraint VARCHAR(10 ), VARCHAR(DEFAULT' Shandong province ' -- default value )Unique constraintCREATE TABLE USER ( INTunique,-- Unique constraint VARCHAR() ,

Today using the IDE connection line under MySQL error can not connect to MySQL server. Too many connections, the error is clear, the connection with MySQL is full. Also, each service creates a MySQL connection pool, which takes up a lot of long

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

template, null value (NULL) self-modificationCreate Database Sky;Use Sky;CREATE TABLE M1 (ID Int (11),Name Char (20),Age tinyint (10),Sex enum (' Male ', ' female '),Score tinyint (10),Address char (20)) default Charset=utf8;INSERT INTO M1 values(1,

then the last blog post MySQL mha+keepalived scenario demo (iv) in the failover of MySQL, the current main library becomes the 192.168.2.129 machine, while the 129 machine on the keepalived service is turned on. However, 192.168.2.128 's original

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,