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MySQL additions, deletions, modifications and modifications

The database is a warehouse for storing data. It is mainly used in financial institutions, game websites, shopping websites and forum websites. Now the mainstream databases are MySQL, SQL_Server, Oracle, Mariadb, DB2, MongoDB. So how do we choose which database to use in a production environment? 1. Open source Open source software: MySQL, Mariadb, MongoDB Commercial software: Oracle, DB2, SQL_Server 2. Cross-platform No cross-platform: SQL_Server Cross-platform: MySQL, Mariadb, MongoDB, DB2, Oracle 3. Type of company Business...

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Basic usage of Sequelize

install $ npm install --save sequelize # You also need to install one of the following: $ npm install --save pg pg-hstore // postgreSql $ npm install --save mysql // mysql or mariadb $ npm install --save sqlite3 $ npm install --save tedious // MSSQL Establish connection const Sequelize = require('sequelize') const sequelize = new Sequelize(db.database, db.user, db.password, { //Table Name User Name Password host: db.host, //address port: db.port, //port dialect: 'mysql', //Database...

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Interpretation of Oracle Connection Configuration

After installing ORACLE database software, dbca needs to configure listener to connect to database after installing database. Here are some concepts that are difficult to understand and record some of the conclusions of the analysis. Start with the connection end. 1. How to connect database oracle's connection string consists of several parts. Here's an example of sqlplus. A completed connection string follows the following format sqlplus username/password@host: port number/SID optional as sysdba Let's start with the case where only listener...

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Servlet 2. HTTP Protocol 3. Request

Content: 1. Servlet 2. HTTP protocol 3. Request Servlet: 1. concept 2. steps 3. Executive Principle 4. Life cycle 5. Servlet 3.0 Annotation Configuration 6. Servlet architecture Servlet -- Interface | GenericServlet -- abstract class | HttpServlet -- abstract class * Generic Servlet: The other methods in the Servlet interface are implemented by default empty, and only the service() method is abstracted. * When defining Servlet classes in the future, you can inherit GenericServlet and implement the service() method. *...

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Extend mybatis and general mapper to support geometry type fields of mysql

Because the storage, query and calculation of geographic location information are needed in the project, it is decided to use the geometry type field of mysql (version 5.7) database to save geolocation coordinates and Virtual Generated Column to save geohash value for easy query. You need to understand how geometry is used and its advantages.Simple use of geometry type in mysqlEfficiency Advantage of MySQL Geometry Extension in Geographic Location Computing This article focuses on extending mybatis and general mapper to support the addition,...

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java web development step - tomcat

java web development process - tomcat 1. Setting up servers server (tomcat) Operational steps: servers - > New - > server - > Apache - > Tomcat 7.0 - > next - > Tomcat Install Location - > Borwse (select the location of tomcate) - - > next - > finish - > you will see a server below the upper servers. 2. Creating Dynamic Engineering Action steps: file -> new -> Dynamic web Project -> project name -> finish 3. Add web.xml file to WEB-INF <?xml version="1.0" encoding="UTF-8"?>...

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The Way to MySQL Learning: SQL Scripting Language

Original Link: https://my.oschina.net/u/1772925/blog/600871 Using the MySQL database, you first install the MySQL database, and all the SQL scripts in this article are tested and executed on MySQL. Install Mysql server;Install the Mysql workbench client to manage mysql with a graphical interface.Install the phpMyadmin client to graphically manage Mysql via bs. 1. Mysql server operations:   Take...