Category:DBT

  • MySQL 8.0.24 installation and configuration method graphic tutorial

    Time:2021-7-30

    This article shares the MySQL 8.0.24 installation tutorial for your reference. The specific contents are as follows Download address: Official Website 1. Unzip folder 2. Configure the environment variable and add the bin directory under Mysql to the path; 3. Create a new my.ini configuration file in the MySQL directory 4. Modify profile [mysqld] #Set […]

  • What is “hybrid cloud”?

    Time:2021-7-29

    In this paper, we define the concept of “hybrid cloud”, explain four different cloud deployment models of hybrid cloud, and deeply analyze the industrial trend of hybrid cloud through a series of data and charts. 01 introduction Hybrid cloud is a computing environment that integrates multiple platforms and data centers. Generally speaking, hybrid cloud is […]

  • Install MySQL for Ubuntu

    Time:2021-7-29

    This article is continuously updated to record the MySQL installation pit encountered 1. Uninstall MySQL sudo rm /var/lib/mysql/ -R sudo rm /etc/mysql/ -R sudo apt-get autoremove mysql* –purge sudo apt-get remove apparmor 2. Installation 2.1. Method 1 sudo apt update //Install mysql5.7 sudo apt install mysql-server -y 2.2. Method 2 dev.mysql.com/downloads/repo/apt/Copy download link //Download curl […]

  • MSSQL · take a record according to the maximum value of multiple fields and grouping according to a field

    Time:2021-7-29

    Reading time |1.14 minutes word count |1825.6 characters primary coverage |1. Introduction & background “MSSQL · take a record according to the maximum value of multiple fields and grouping according to a field” Author | SCscHero Writing time | 2021/7/12 PM12:0 Article type |Series Degree of completion |Completed motto Every great cause has a trivial […]

  • Buffer pool – Notes on MySQL 8.0 official documents (V)

    Time:2021-7-29

    Document version: 8.0Source:buffer poolPrevious:How to reduce and handle deadlocks This article mainly introduces the buffer pool of InnoDB. Buffer pool is an area where InnoDB caches table and index data in memory. Through the buffer pool, the frequently used data can be accessed directly in memory, so as to speed up business processing. On a […]

  • Graphic tutorial of MySQL 8.0.24 installation and configuration method

    Time:2021-7-29

    This article records the installation and configuration method of MySQL version 8.0.24 and shares it with you Download MySQL from the MySQL official website After downloading, double-click directly to install. The open page is as follows: Select custom, and then go to the next step Expand MySQL server and add it to the right (click […]

  • Method of simple sub query of SQL Server 2019 database

    Time:2021-7-29

    Subquery can complete complex situations in SQL query. This chapter mainly introduces the simple usage of some subqueries. 1、 Simple subquery 1. Simple subquery A subquery is another select statement within a select statement. In general, subqueries can be used wherever expressions can appear in a statement. In addition, subqueries can extract data from any […]

  • [database] MySQL exercises and answers (educational administration management system)_ MySQL_ 5.7)

    Time:2021-7-28

    ✨ statement The answer to the exercise is not guaranteed to be completely correct, which is for reference only MySQL:5.7 Recommended software: Navicat premium Learning SQL statements requires diligent practice! ✨ Field description of each table course CId Course serial number, primary key PCId Prerequisite course DId Opening department number, foreign key CName Course name […]

  • CentOS 8.2 deploying CouchDB 3.3 database

    Time:2021-7-28

    CouchDBIs an open source, document oriented NoSQL database. In this article, you will learn how to install Apache CouchDB on CentOS 8. catalogue What is Apache CouchDB? Environmental specifications: Step 1: update CentOS 8 package Step 2: install EPEL Yum repository on CentOS 8 Step 3: install CouchDB Yum repository on CentOS 8 Step 4: […]

  • Differences between exists and in in SQL statements

    Time:2021-7-28

    select * from A where id in(select id from B) Conclusion: in () is suitable for the situation that the data in table B is smaller than that in table a select a.* from A a where exists(select 1 from B b where a.id=b.id) Exists is used to check whether a subquery will return at […]

  • MSSQL · query and sort the records of all tables in a database

    Time:2021-7-28

    Reading time |0.27 minutes word count |444 characters primary coverage |1. Introduction & background “MSSQL · query and sort the records of all tables in a database” Author | SCscHero Writing time | 2021/7/13 PM10:0 Article type |Series Degree of completion |Completed motto Every great cause has a trivial beginning. 1、 Introduction & background    Completion: […]

  • On the execution process and sequence of MySQL

    Time:2021-7-28

    MySQL is basically faced every day in our development. As the source of data in development, MySQL undertakes the responsibility of storing data and reading and writing data. Because it is very important to learn and understand mysql, what kind of process did we go through when we launched an SQL on the client and […]