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How does Spring Security store user data into the database? Up to now, we haven't connected to the database. In real projects, in most cases, we design our own permission database. However, Spring Security also provides us with a permission database designed by itself. Let's see what's going on first! Let's learn this simple one first, and the ...

1, MHA overview MHA (MasterHigh Availability) is a set of excellent software for failover and master-slave replication in MySQL high availability environment. The emergence of MHA is to solve the problem of MySQL single point. During MySQL failover, MHA can automatically complete the failover operation within 0 ~ 30 seconds. MHA can ensure ...

I recently learned the "Java Concurrent Programming Practice" of geek time, and I have a new understanding of java thread pool and my own understanding, as well as some ideas, such as whether I can design a distributed thread pool, whether I can design a thread pool that can dynamically modify parameters, and whether I can design a th ...

1, Connection query Classification according to the way of table connection: Internal connection: equivalent connection, non equivalent connection and self connection External connection: left external connection (left connection), right external connection (right connection) Syntax: join ... on ... select ... from Table name 1 join Table na ...

1. DQL operation sheet 1.1 create database and copy tables Create a new db2 database CREATE DATABASE db2 CHARACTER SET utf8; Copy the emp table in the db1 database to the current db2 database 1.2 sorting The sorting effect of the query can only be displayed through the order clause, and the sorting effect will not be displayed thro ...

catalogue 1, MySQL PRIMARY KEY Set primary key constraint when creating table Set federated primary key when creating table Delete and modify primary key constraints II. MySQL FOREIGN KEY constraint and UNIQUE constraint Set foreign key constraints and unique constraints when creating tables 3, MySQL CHECK constraint (CHECK) Delete ch ...

Introduction to Exception and the use of transactions 1, Java exceptions: Error and Exception 1. Overview of exception mechanism The exception mechanism refers to how the program handles when an error occurs in the program. Specifically, the exception mechanism provides a safe channel for the program to exit. When an error occurs, the proces ...

Common statements: --show database SHOW DATABASES; #Create a table score in stuinfo, including column id,name, and grade scores --Select database USE stuinfo; --Create table CREATE TABLE score(    id INT,    -- auto_increment Automatic growth    NAME VARCHAR(20),-- varchar() Variable length string    grade INT); #Query table Syntax: sele ...

preface In our daily APP or website, we often need to access data. For example, in wechat, we need to store a series of information such as our user name, mobile phone number, user password, etc. Relying on the Java related knowledge learned before can no longer meet this demand. Now the most basic and widely used application program is relati ...

Virtual machine installation, Linux system and software installation Environmental Science: Software selection: server with GUI Network type: use network address translation (NAT) Power on automatic networking cd /etc/sysconfig/network-scripts/ vim Network profile //ONBOOT = "no" is changed to yes, and there is no need to conne ...