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In the process of online MySQL installation, since centos7 was used for the first time, it took a long time to record the successful configuration method. Modify yum source Enter the local machine to modify the yum configuration file Enter yum.com repos. D directory cd /etc/yum.repos.d/ Add the existing Yum source: / etc / yum repos ...

1. Disadvantages and advantages of MySQL single server Disadvantages: Single server If disk problems occur, database data will be lost Backup of a single server makes it difficult to automatically and regularly back up data files if they are backed up locally Single server can not handle high concurrent reading, only a single one, read and ...

Common operation show databases; Show all databases use dbname; Open database: show tables; show database mysql All tables in; describe user; Display table mysql In database user Column information of table); Connector mysql ‐ h host [database address] - u root [user] - p root [password] - P 3306 Mysql client connection server Verify host ...

mysql commands executed on the mysql client: 1. Use the value "where" to filter and display some selected rows. SELECT * FROM [table name] WHERE [field name] = "whatever"; Display all records with name "Bob" and phone number "3444444". SELECT * FROM [table name] WHERE name = "Bob" AND phone_number = '3444444'; ...

preface After consulting the official documents of mybatis plus, I found that there were only a few words and no examples for multi table joint query. I had to figure out how to use mybatis plus for multi table joint query. The way of using xml is too redundant, so after checking the use of annotations, we decisively choose to use annotations. ...

1. First understand the difference between compilation and installation and yum installation. Install centos virtual machine under windows, which was written before. Portal~~ Compile and install: It can be installed on demand. It can be installed in whatever directory you want.Parameters can be setYou can install the version you wan ...

mysql Operations and Maintenance Basic Interview Questions and Answers Interview Question 001: Explain the concept and main features of relational databases? Answer: The relational database model refers to the simple binary relationship of complex data structure. All the operations on data are to establish one or more relational tables. T ...

1. Get to know MySQL When I first started learning java last year, I saw the video of crazy teacher. Now I integrate the notes I made before and publish it for your reference javaEE: Enterprise java Web Development Front end (page: display, data) Background (connection point: connect to database JDBC, connect to the front end (control ...

Primary key generation strategy 1. What is a primary key? Primary key, that is, primary key, is the candidate key selected as the unique identification of the row of the table. A table has only one primary key. A primary key can also be called a primary key. A primary key can consist of one field or multiple fields, which are called sing ...

There are many ways of MySQL master-slave replication. This paper mainly demonstrates the master-slave replication based on binlog. Principle of MySQL master-slave replication (also known as A/B replication) The Master records the data changes in the binary log, that is, the file specified in the configuration file log bin, These records are ...