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Four system databases of MySQL +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | sys | +--------------------+ It is used to store information such as MySQL server, database and system performance. mysql Mysql database is the core da ...

This article comes from Alibaba cloud official mirror: Alibaba open source mirror - OPSX mirror - Alibaba cloud developer community ] Original link: Manual deployment of MySQL database in CentOS - Alibaba cloud developer community 1, Preconditions Registered alicloud account.If you use ECS in mainland China, please ensure that your account h ...

Using sql statements to operate the database Create database Syntax: CREATE DATABASE [IF NOT EXISTS] db_name [CHARACTER SET charset_name] [COLLATE collation_name] Where charset_name is the default character set specified for the database Collate is the default collation rule specified for the database (collation rule is a set of rules us ...

Course notes Day28 Database paradigm Database transaction Database view Backup and restore Chapter I database paradigm Section 01 basic theory What is the database paradigm? When designing a table, we need to follow some database design specifications. Why use paradigms? In order to reduce the data redundancy in the database. ( ...

After finishing these 33 questions, we don't have to worry about the written sql test any more. We don't talk much nonsense. Let's go straight to the dry goods!!! 1: Title 1. Query the Sname, Ssex, and Class columns of all records in the Student table. 2. Query all the companies of teachers, that is, the non duplicate Depart ment column. 3. ...

preface: The database used by the following MySQL functions: Link: https://pan.baidu.com/s/1N8uoyj0Wv6nq4zFdEnmGBw Extraction code: 6666 1, Single line function 1. Character function length gets the number of bytes of the parameter value SELECT LENGTH('john'); result: concat splice string SELECT CONCAT(last_name,'Splicing',first ...

Linux server development / background architect knowledge system arrangement Is it a blessing or a pit? If you don't know the principle of MySQL locking, you will be miserable by it! I don't know where the pit is? It's okay. I'll mark some pits for you. Don't step on it when you meet it. Through the contents of this chapter, you will learn MyS ...

1. Project background and demand analysis 1.1 project background E-mail is widely used in enterprises. E-mail is generally used for communication and business between employees and customers. However, due to the lack of awareness of managing e-mail in many enterprises, a large number of e-mail management is chaotic, and there are some hid ...

Simple message board implemented by JavaWeb+MySQL Hello, dear friends, I'm the Bug terminator ~. Unconsciously, I've been on holiday for 2 weeks. I've come to Monday. Today, I decided to update the article. Today, I'll bring you some experience in my learning process and avoid pitfalls for my friends. Let's share today Message board requ ...

Chapter 25 JDBC and database connection pool 821. Schematic diagram of JDBC JDBC provides a unified interface for accessing different databases and shields the use details for users. Java programmers can use JDBC API to connect to any database system that provides jdbc driver, so as to complete various operations on the database The Java de ...