MySQL

Why do you create an index? This is because creating an index can greatly improve the performance of the system.First, by creating a unique index, you can guarantee the uniqueness of each row of data in a database table.Second, it can greatly speed

Installation of 1,mysql: http://jingyan.baidu.com/article/642c9d34aa809a644a46f717.htmlIf you reinstall, you will need to uninstall MySQL completely before you install this step. At the time of installation, the password can be modified without

1. Installation & ConfigurationUsing Ubuntu 16.04 LTS operating system, directly using the Apt-get install Mysql-server installation, the middle needs the database root user's password, records well. Use Mysql-v to view the version after the

to view the index of a tableShow create table name; Show index from table name; show keys from table name;Add indexALTER TABLE name add index index name (index field);ALTER TABLE goods Add index price (shop_price);1.PRIMARY KEY (PRIMARY KEY

Xtrabackup at the time of the backup while reading the Redolog and bin-log position, and finally apply the Redolog to the database file, it is possible to implement the hot standby machine, do not lock the table to synchronize the master data to

When concurrent transactions access a resource at the same time, it is possible to cause inconsistent data. Therefore, a mechanism is needed to order access. A lock is one of the mechanisms.Operations on the database can be summarized as two, read

One: The principle of database connection poolingThe database connection pool holds some database connection objects (connection objects), and when you manipulate the databaseGets the connection object directly from the connection pool, and then

One: Install MySQLcan go to the official website to download, here will not wordySecond: After installation, we first run MySQL to see, open the Cmd interface, enter "Mysql-u root-p", because the landlord did not set the password, the following

First, FOREIGN KEY constraintsEnsure the integrity of the data.To define a FOREIGN KEY constraint:Foreign keys can be defined directly in the CREATE statement foreign key current table name (field name) References target table name (primary key of

Name Age Phone Chen 25 134xxxx Zhang 30 158xxxxx Grammar: create procedure Procedure name ([ [in| Out| INOUT parameter name data type [ ,[in| Out| INOUT parameter name data

1.1 RequirementsDatabase 3 million user data, traverse get all users, various combinations associated, get to a new JSON, save to Redis.1.2 DifficultiesDatabase is much more, it is impossible to single-threaded query all the data to memory.1.3

Environment Description:Red Hat Enterprise Linux Server Release 6.5Mysql-5.6.34-linux-glibc2.5-x86_64.tar.gz1. Create users and Groups:[[email protected] ~] - + MySQL [[email protected] ~] - -p MySQL2. Create the installation package upload

When using MySQL, it is sometimes necessary to query a record for a field that is not duplicated, so you can use the DISTINCT keyword provided by MySQL to filter duplicate records, but in practice we often use distinct to return the number of

Error: Unable to open underlying table which is differently defined or of Non-myisam type or doesn ' t existSo when encountering unable to open underlying table which is differently defined or of Non-myisam type or doesn ' t exist error, you need to

1. Using the mysqldump commandBackup: Mysqldump-u username-p dbname table1 table2 ...> backupname.sqlRestore: Mysql-u username-p [dbname]Mysqldump-u root-p123456MySQL user servers> Backup.sql//put the library under MySQL table user, table servers

Today in the design of the table, there is a small problem, because do not know how long the future will be stored data (data is provided through the third-party HTTP interface, according to sample display, the data is probably as follows:)That is, 6

Tips and notes for using mysql indexes, and tips for using mysql IndexesI. Functions of Indexes In general application systems, the read/write ratio is around, and insert operations and general update operations rarely encounter performance problems.

Mysql date and character conversion, mysql date conversion Today, I found some usage of the MySQL database date conversion function on the Internet. Here I will record it: Mysql date and character conversion Date_format (date, '% Y-% m-% D ')-----

Basic MySQL knowledge and basic MySQL knowledge I. Five clauses of MySQL query: 1. where (conditional query), common operators: ① Comparison Operator >,=, ② Logical operators Non-logical: not /! , Logical or: or/|, logical and: and /&& ③ Fuzzy

MySQL System variable configuration Basics Source: http://www.cnblogs.com/wy123/p/6595556.html MySQL variable ConceptI personally think it can be understood as some parameter issues read during MySQL startup or running. These parameters are used to