MySQL

1.sql Statement Classification:DQL Statement data Query Language SelectDML statement Data manipulation Language Insert Delete updateDDL statement Data Definition language Create drop alterTCL Statement Transaction Control Language commit rollback2.

First you have to have a ballpark understanding of MySQL.For example: How to install, use the basic syntax, test the installation can be successful, and successful after the simple database, operation (increase and deletion) ...Here is the business

1. Download: Http://dev.mysql.com/downloads/mysql/5.6.html#downloadsDownload version: I choose here 5.6.33, General edition, Linux under 64-bitYou can also directly copy the 64-bit, download by command: wget http://dev.mysql.com/get/Downloads/MySQL-5

1. Install dependent packagesYum-y Install Ncurses-devel Libaio-devel2, download CMake package, unzip, compileWget-q https://cmake.org/files/v2.8/cmake-2.8.8.tar.gz TAR-XVF cmake-2.8.8.tar.gzcd cmake-2.8.8./configureCompile error is generally

1 Code1.1 When the current field is empty, the result of the query returns "None" and the frequency of statistics occursSelect Case when field is null then ' none ' else field end as field, Count (1) as counts from table group by field;1.2 When the

Optimization: Storage layer: Data table "Storage Engine" selection, field type selection, inverse paradigm (3 paradigm) Design layer: index, partition/table schema layer: Distributed Deployment (master/Slave mode/shared) SQL statement layer: In the

In the actual business production system, MySQL from the library will sometimes change the main library according to the actual needs, when we need to clear out the library configuration of the master and slave informationLog on from the library to

apiVersion:v1kind:ReplicationControllermetadata: name:mysqlspec: 1 selector: app:mysql Template: metadata: Labels: app:mysql Spec: containers: - name:mysql

MyD is a file that stores data, and Myi is an index file.The index improves the query speed, reduces the speed of adding and deleting, not the more the better.Type of index:1, key, general index2. Unique key, single indexCREATE TABLE T12 (Name Char (

I. Zoning ConceptsMySQL 5.1 supports partitioning later, a bit similar to the concept of sharding in MongoDB. It is in accordance with certain rules, a database table into a number of small tables, these small tables can be physical partitions, is

In the practice project, MySQL row-level locks are not used. Instead, the use of inventory increases and decreases through RABBITMQ queues. Two tables update data by displaying the Create transaction implementation. During the testing process,

A few common commands:Select Database (); #查看当前所在的数据库.Select User (); #查看当前登录的用户Knowledge points that may be missed:In the InnoDB storage engine, you must have a primary key in a table, and when you do not specify a field as the primary key, InnoDB

First step: Stop the Service/etc/init.d/mysqld stopStep two: Add parameters to start the serviceCd/application/mysql/bin/mysqld_safe--skip-grant-table--user=mysql--skip-networking &This mode: No password login network users can not log on only local

1. Displays the names of all databases in MySQL, show databases;2. Access a database, user database_name;3. Displays the names of all the tables in the current database, show tables;4. View the current Data warehouse, select Database ();5. View all

Definition: A data structure that is specifically designed to help users quickly query data in a database. Similar to a directory in a dictionary, you can find the contents of the dictionary based on the directory to locate the data, and then get

Description: MySQL backup is not as simple as SQL Server, the database engine type needs to be backed up, and now the mainstream is two: InnoDB and MyISAM, and the two types of backup methods are different.MyISAM: Mysqlhotcopy InnoDB:

#Coding:utf-8ImportMySQLdbImportSYSReload (SYS) sys.setdefaultencoding ('Utf-8')classMysqldbhelper:#Get database connection defGetcon (self):Try: Conn=mysqldb.connect (host= 'localhost ', user= ' admin ', passwd= ' admin ', DB=test ', Port=3306,

sql:struct Query LanguageHost: HostsUser: UsersPassword: passwordData:Database: Databasestable: TablesColumn: Columnsfield: ColumnRow : LinePort: Portsquit: Cancel, exitExit : ExitCharSet: Character set, character encodingCOLLATE: Sorting

To Java, so the service side also toss a bit of Linux.The following content are relatively novice, do not spray, forgive me.Installation of CentOS. Installation interface has a network settings, be sure to choose to connect, or enter the

Statement: The material used in this column is written by the VIP students of the Kay Academy, who has the right to be anonymous and has the final right to interpret the article; The Edith Academy is designed to promote students to learn from each