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Classification of variables in MySQL Variables are divided into system variables and user-defined variables System variables: also divided into global variables and session variablesUser defined variables: divided into user variables and local variables 1, System variable System variables are provided by the system, not user-defined, and ...

JDBC overview Basic introduction Simulate JDBC public class TestJdbc { public static void main(String[] args) { JdbcInterface jdbcInterface = new MysqlJdbcImpl(); //Complete the operation of mysql jdbcInterface.getConnection(); jdbcInterface.crud(); jdbcInterface.close(); } } //jdbc interfa ...

Install Redis Download package On the official website https://redis.io/download install Download redis-6.2.6 tar. GZ file Use Xshell to transfer files into the virtual machine Using sftp protocol, the host ip is the ip address in ens33 in ifconfig on the command line. For the first time, you need to enter the virtual machine login acc ...

1, Meaning of subquery Meaning: select statements that appear in other statements are called subqueries or intra queries; The external query statement is called primary query or external query Classification: According to the location of sub query: After select: only scalar subqueries are supported After from: only table subqueries are ...

Original tutorial address Nedb -- Node embedded database Simple demo <template> <div> <el-button type="primary" @click="addOneUser">Add user</el-button> <el-button type="primary" @click="search">query</el-button> </div> </template> <script> // Import related metho ...

catalogue 12.1MySQL configuration file (1) Configuration section (2) Basic configuration (3) Memory and optimized configuration (4) Log configuration 12.2 data backup and restore (1) Data backup (2) Data restore (3) Binary log 12.3 multi instance deployment 12.4 master slave replication 12.1MySQL configuration file (1) Configu ...

This note is the learning content of Alibaba cloud Tianchi Longzhu program SQL training camp. The link is: https://tianchi.aliyun.com/specials/promotion/aicampsql Exercise 1 Please use the quarterly revenue forecast data sets "Income Statement.xls", "Company Operating.xlsx" and "Market Data.xlsx" of A-share liste ...

1 Overview 1.1 what are the sub warehouse and sub table Xiao Ming is a developer of a start-up e-commerce platform. He is responsible for the function development of the seller module, The related businesses of shops and commodities are involved, and the design is as follows Database: Store information and geographical area inform ...

It should be very common for everyone to use redis cache in the project. We used stackexchange before Redis. Inadvertently browsed a post * * net core 2.0 redis driver performance competition * *, it is found that there are two shorter and stronger components: CSRedis and newlife Redis is actually like servicestack Redis . ServiceStack.Redis ...

TiUP is a cluster operation and maintenance tool introduced by TiDB version 4.0. TiUP cluster is a cluster management component written by Golang provided by TiUP. Through TiUP cluster component, you can carry out daily operation and maintenance work, including deployment, startup, shutdown, destruction, elastic capacity expansion, upgrading Ti ...