MySQL

Let's make an analogy.There are a lot of students in a class, they have different school numbers respectively . A student corresponds to a school number, a school number corresponds to a student; the relationship between students and student numbers

Knowledge Reserve:1, the MySQL crasy recovery is through the redo log and the undo log to complete;2, redo log and undo log is the physical operation of the page, such as the 1024th page offset to 100, write ' Hello World ', which means redo log and

1. General Find operation1 SELECT 2 ccid,apply_date3from4 cms_user_courses 5 WHERE6 =126;2. Based on the CCID grouping lookup , use Group by to group, use Group_concat to connect all duplicate data, if not applicable Group_concat Only

MySQL master-slave replication several important boot options　　(1) log-slave-updatesLog-slave-updates This parameter is used to configure whether updates from the server are written to the binary log, this option is not opened by default, but if

Profile:In the project development, often have such a scenario, the database to add, modify, delete the application of the operation directly connected to the master library, only the database query application, will first establish a central cache,

Data constraints: Constraints on user action data tables1. Default valueFunction: When the user does not insert a value to a field that uses the default value, the default value is usedCreate Table Student ( int, varchar() ,varchar

One: Unpack the installation package in the/usr/local directoryII: MySQL directory structureThree: Add user group MySQL, add user mysql, give/usr/local/mysql directory to MySQL user. Install the MySQL service and generate a temporary password for

Backup: Mysqldump-u user-p pwd-h host Dbname[tbname,[tbname ...] >filename.sql---(logical backup)-q or -quick    ----does not occupy memory-w  "Where clause"  or -where =   where clause     ----conditions--all-databases -----All databases--databases 

View database show databases;The new Database command creates the library name.Select database Use 2016test;CREATE TABLE: Create table table name (Field ....);Auto_increment Self-incrementPrimary KEY Primary KeyView table structure: Describe table

mysql:error while loading shared libraries:libmysqlclient.so.15:cannot open Shared object file:no such file or dir EctoryBecause the loading and unloading of the old version of RPM, the old version left a lot of MySQL commands, when the MySQL

　1. Description: Create DatabaseCREATE DATABASE Database-name　　2. Description: Delete DatabaseDrop Database dbname　3. Description: Back up SQL Server---to create a device that backs up dataUse masterEXEC sp_addumpdevice ' disk ', ' testback ', '

Reprinted from: http://blog.csdn.net/ofreelander/article/details/508027801.my-default.ini renamed My.iniCopy the My-default.ini under the extracted directory and change the name to My.ini.2. Open the Windows environment variable settings, new

MySQL indexing principle# #索引目的The goal of the index is to improve the efficiency of the query, you can analogy dictionary, if you want to check the word "MySQL", we definitely need to locate the letter M, and then find the Y letter from the bottom,

String intercept left (), right (), substring (), Substring_index ()Left (Str,length)Right (Str,length)SUBSTRING (str,pos) starts at POS character position until end (POS is negative for reciprocal)SUBSTRING (Str,pos,len) starts at POS character

INSERT into Rpt_tr_cinema_ticket_trade_detail (IdTrade_date,SCINEMA_CD,Opt_type,TRADE_CHANL,FILM_CD,HALL_CD,Cinema_name,Film_name,Show_date,Show_time,Ticket_type,Ticket_group,BOOKING_ID,Ticket_no,Seq_no,ROW_ID,COL_ID,Payment_seq,Payment_type,Payment_

zabbix3.0 server has its own template for MySQL , just configure the agent client, and then add the template to the host on the web side.The following is the company's online zabbix3.0 environment to add MySQL monitoring operation recordzabbix_agent

When MySQL create table, it is sometimes necessary to specify data_type lengthHttp://dev.mysql.com/doc/refman/5.5/en/create-table.htmlBut the length of the type a lot of development does not understand, understanding can be divided into two1) Number

Mysql basic, mysqlMysql-u root-pEnter the password to enter the databaseShow database;Query Current DatabaseUse databasenameSwitch to a databaseShow tables;List the tables of the current databaseDesc tbalenameList table fieldsSelect user ()+ --------

Distributed consistency algorithms-Paxos and consistency-paxos Paxos is a consistent algorithm based on message transmission proposed by Leslie Lamport in 1990. The Paxos algorithm solves the problem of how a distributed system can reach an

MySQL methods and frequently asked questions in EF, efmysql Sometimes you need to rent a space or database online. Mysql is cheaper, so you want to convert SQL server to mysql ......Note: When installing Mysql, You must select utf8 as the text set.