MySQL

/** * Creator: CALVINR * Description: Database helper class **/namespacestudy.utilities.mysql_connect{/// ///Summary description of Mysqlhelper/// Public classMysqlhelper {PrivateMysqlconnection conn =NULL; PrivateMysqlcommand cmd =NULL;

1.mixed pdo::errorcode ( void)If this statement is executed separately, it is not possible to determine if MySQL is disconnected at this time, it returns the last error code for MySQL operation2.public array pdo::errorinfo ( void) If this

1. MySQL master-Slave synchronization configuration 1.1. Basic informationDatabase master server ip:127.0.0.1Database from server ip:192.168.1.311.2. Primary server configuration file My.ini configuration (Master)[Mysqld]#打开日志 (the host needs to

1.Installation Environment:[Email protected] ~]# cat/etc/redhat-releasecentos Linux release 7.3.1611 (Core)Mysql Version number: Mysql-5.7.13-linux-glibc2.5-x86_64.tarEach configuration path: installation File download directory:/data/software

####################################################################################What is a database:Db,databaseDatabase: A data set that is organized and placed into memory according to a data model.Dbms,database Management System--"Database

MySQL must know2017-12-21Significance: Record personal unnoticed, or unclear, or unknown details method skills, this book 250 pagesLanding:Mysql-u root-p-H myserver-p 9999Show status, used to display extensive server status informationDESCRIBE

1. Optimize flowchartMySQL optimization (mainly increase the database select query, make the query faster)2. optimizing the MySQL aspectMainly from the following four aspects to optimize MySQL① Storage Tiers: How to select a database engine, select

This article was also published in HTTPS://GITHUB.COM/ZHANGYACHEN/ZHANGYACHEN.GITHUB.IO/ISSUES/53Lock and latchIn a database, both lock and latch can be locks, but both have distinct meanings.Latch is generally called a latch (lightweight lock)

1.LINUX-NODE2 Node Installation database[[email protected] ~]# yum install-y mariadb-server[[email protected] ~]# systemctl start mariadb[[email protected] ~]# N ETSTAT-TULNP |grep 3306tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 41299/mysqld2.Zabbix

　　First PitTo connect to the database, we must have Mysql-python This module, first of all, I installed this module when the first big pit.General installation method: Go to cmd using pip install Mysql-python can, if you can install that is lucky ah.

EnvironmentMySQL is installed on CentOS and needs to be upgraded.The MySQL version ismysql> select version();+-----------+| version() |+-----------+| 5.1.73 |+-----------+1 row in set (0.00 sec)The CentOS version islsb_release -aLSB Version:

MySQL is a true multi-threaded, multi-user SQL database service that has become the most popular open source database system in the server domain with its high performance, reliability, and ease of use. Currently, the Oracle company is responsible

Smaller is usually betterAt the beginning of the table design, I think the choice of the right data type here is very critical, he can minimize the disk footprint of the database, and in the process of querying the simpler the smaller the data type

PIP installation Ipython Error Record#pip Install ipython==5.5.0collecting ipython==5.5.0  downloading http://mirrors.aliyun.com/pypi/packages/08/2c/ 6285504003b4eadce5540f3ee3adc081468b26723f3eef07d9d5d7d97ed8/ipython-5.5.0-py2-none-any.whl  (758kB)

Reprint: https://www.cnblogs.com/notejava/p/7124189.htmlInstall the MySQL service using the official Docker image1 Pull MySQL image, use netease acceleration addressDocker Pull hub.c.163.com/library/mysql:5.72 Renaming a mirror nameDocker tag hub.c.1

bigint-2^ (-92233720368547758082^1 ( 92233720368547758078intfrom-2^ to(-2,147,483,648) to2^ to–1(2,147,483,647Integer data (all numbers). Storage size is4A byte.intThe sql- thesynonymous word is integer. smallint from-2^ the(- +,768) to2^ the–1( +,7

Connecting to a database mysql-hlocalhost-uroot-pIn MySQL with the directory fileShow Databses;Show all databasesWorkaround 1: Locate My.ini in the MySQL installation directory, change the default-character-set=latin1 under [MySQL] to

The significance of parameterization is no longer mentioned, and the individual considers that there are two situations in which parameterization is used:1. In order to get a series of data for different users to use, such as concurrent registration

In MySQL, there is a function called "Group_concat", the usual use may not find the problem, in the processing of big data, you will find that the content is intercepted,In fact, MySQL internal to this is set, the default is not set the length is 102

Records of problems encountered during MySQL usage and mysql usage Here we will record some problems encountered during the use of MySQL and the corresponding solutions. SQL _mode = only_full_group_by: the group by query error is