mysql database technology 1 - Basic addition, deletion and alteration sql statements

1. Classification of database languages DDL: Database Definition Language Used to create, modify, and delete data structures within a database, such as: 1: Create and delete databases (CREATE DATABASE || DROP DATABASE); 2: Create, modify, rename, delete tables (CREATE TABLE | ALTER TABLE | RENAME TABLE | DROP TABLE, TRUNCATE TABLE); 3: Create a ...

Posted by timmerk on Tue, 11 Feb 2020 20:46:07 -0800

The book management system of Java practice (swing version) - other interfaces and function realization

Summary of this section This section mainly realizes the final function of the software and some summary of the project.   About the function of software The function of the software is to pop up a dialog box, tell the user some information about the software, and use the JDialog of swing to comp ...

Posted by opalelement on Tue, 11 Feb 2020 09:50:28 -0800

SpringBoot+Security dynamic configuration permission

Preface In today's web development, the authentication of security rights has always played an important role, so Spring has also produced its own security module, but this is a relatively heavy framework, configuration is quite cumbersome. Later, shiro, a lightweight security framework, emerged. The ...

Posted by spaze on Tue, 11 Feb 2020 05:32:51 -0800

MySQL transaction, permission, index and specification

One transaction Core: success or failureAtomicity Both succeed or fail Consistency The data integrity before and after the transaction should be consistent, 1000 Principle: ACID1. Atomicity Either they succeed or they fail; 2. Consistency Data integrity before and after transactions should be consiste ...

Posted by nawal on Tue, 11 Feb 2020 02:41:44 -0800

Using spring boot + mybatis + RabbitMQ + redis to simulate the second kill function of the mall

Using spring boot + mybatis + RabbitMQ + redis to simulate the second kill function of the mall First, we need to install RabbitMQ. Before installing RabbitMQ, we need to install Erlang, because RabbitMQ is based on Erlang. For specific steps, click the following link: After installation, RabbitMQ i ...

Posted by newjsguy on Tue, 11 Feb 2020 01:49:52 -0800

Data Structure Handwriting Tree Traversal (Full Implementation)

1. Summary of Previous Situation This is a tree traversal implementation. To focus on how queues are implemented, follow these articles:Data structure (3) Handwritten queues2. Basic concepts of trees Chain lists, stacks, and queues are one-to-one linear structures, one-to-many linear structures - trees. ...

Posted by amrigo on Mon, 10 Feb 2020 21:47:25 -0800

What does -e mean in mysql database?Detailed use of the -e parameter

Can be manipulated with shell scripts mysqldata base , mysql-e parameter can be used to perform various sql operations (create, delete, add, delete, change, check). usage The sql statement of mysql-hhostname-Pport-uusername-ppassword-e related MySQL allows you to manipulate mysql's methods in a shell without running MySQL at ...

Posted by n14charlie on Mon, 10 Feb 2020 08:26:27 -0800

Spring security failed to properly catch UsernameNotFoundException exception

Preface In Web application development, security has always been a very important aspect. In the huge spring ecosystem, the authority verification framework is also very perfect. Among them, spring security is very easy to use. Today, I'd like to record a spring security related problem encountered in development. Problem description When using ...

Posted by V-Man on Mon, 10 Feb 2020 08:07:01 -0800

tomcat multi instance jpress

Made by two couples 1. Basic environment preparation Step 1: download the installation package # wget -P /app/tools/ https://mirrors.tuna.tsinghua.edu.cn/apache/tomcat/tomcat-8/v8.5.50/bin/apache-tomcat-8.5.50.tar.gz # wget -P /app/tools/ http://47.111.238.157/jd ...

Posted by deejay on Mon, 10 Feb 2020 05:59:16 -0800

Quick learn - MyBatis map file

Chapter 4 MyBatis mapping file 4.1 introduction to mybatis mapping file The real power of MyBatis lies in its mapping statement and its magic. Because of its extraordinary power, the XML file of mapper is relatively simple. If you compare it with JDBC code with the same function, you will immediate ...

Posted by wtg21.org on Mon, 10 Feb 2020 04:20:58 -0800