How nodejs+mysql operates the database

This time I will show you how nodejs mysql operates the database, and what are the precautions for nodejs mysql operating the database. The following is a practical case, let's take a look.

1. Several commonly used global variables

1, __filenameGet the path of the current file
2 , __dirnameGet the directory of the current file
3, process.cwd()Get the directory of the current project

2. File Import and Export

1. Use require to import the file

2. Use module.exports to export the file specified in the Variables, methods, objects

3. node Project directory structure

##demo

package.json The package or module that the current project depends on
router The file that stores the routing
views The file that stores the view Module
public Static file
module Writing module such as database
app.js Main entry file

4. Write the routing view separately in the router filedemo

1. View view file

const express = require("express");
const router = express.Router();
router.get("/", (req, res) => {
 res.send("hello word");
});
router.get("/article", (req, res) => {
 res.send("我是文章列表");
})
module.exports = router;

2. Call

'use strict';
const express = require("express");
const app = express();
app.use("/",require("./router/03_router"))
app.use("/app",require("./router/03_router1"))
app.listen(3000);

in the main file. Five. Use ejstemplate

1. Need to install but don’t need to introduce

npm install ejs --save

2. Configure

//配置模板的文件路径
app.set("views",__dirname+"/views");
//配置模板引擎
app.set("view engine","ejs");

3 in the main file. Use

①, template file

 
 
 
 


我是模板渲染的

②. Rendering the template in the route

'use strict';
const express = require("express");
const router = express.Router();
router.get("/", (req, res) => {
 //可以直接使用res.render("03_index");
 res.render("03_index.ejs");
});
router.get("/article", (req, res) => {
 res.send("我是文章列表");
})
module.exports = router;

③. Main file

'use strict';
const express = require("express");
const app = express();
//配置模板的文件路径
app.set("views",__dirname+"/views");
//配置模板引擎
app.set("view engine","ejs");
app.use("/",require("./router/03_router"))
app.use("/app",require("./router/03_router1"))
app.listen(3000);

6. About the ejs template file Use

1, return data

...
let dataset = {
 name:"张三",
 age:20,
 books:['三国演义','西游记','红楼梦','水浒传']
}
res.render("03_index.ejs",dataset);
...

2, ordinary fields

<%= name %>
<%= age %>

3, iterate array

 <% for(let i in books){%>
  
<%= books[i] %>
 <%}%>

7. Load static files

1. Configure

//设置静态文件的加载(js,css,img)
app.use(express.static(__dirname+"/public"));

# in the main file. 2. Use

...

# in the template. ##8. Use mysqldatabase1. Create a

db.js in

module ’s file

'use strict';
const mysql = require("mysql");
/**
 * 将整个方法全部暴漏出去
 * @param sql sql语句
 * @param arg 传递到sql语句中的参数，可以不写
 * @param callback 回调函数，可以不写
 */
module.exports = function (sql,arg,callback) {
 //1.创建连接(根据自己的数据库配置)
 let config = mysql.createConnection({
  host:"localhost", //数据库的地址
  user:"root", //数据库用户名
  password:"root", //数据库密码
  port:"3306", //mysql数据库的端口号
  database:"mybatistest" //使用那个数据库
 });
 //2.开始连接数据库
 config.connect();
 //3.对数据库的增删改查操作
 config.query(sql,arg,(err,data)=>{
  callback && callback(err,data);
 })
 //4.关闭数据库
 config.end();
}

2. Use the query data in the

router

view①.Introduce the file

//引入数据库文件
const db = require("./../module/db");

②、Use it in the view

router.get("/", (req, res) => {
 db("select * from m_dept",(err,data)=>{
  console.log(data);
  res.render("03_index.ejs",{data:data});
 })
});

3. New data

①. See the code example on the front-end page

②. Obtain user data parameters through

req.query

router.get("/regist",(req, res)=>{
 //获取到输入参数，前提是input上要写name
 console.log(req.query);
 db("insert into student(name,age) values(?,?)",[req.query.username,req.query.age],(err,data)=>{
  console.log(data);
  if(data){
   res.send("成功");
  }
 })
})

9. About the way node returns json In the front-end and back-end separation development model, the data returned by the back end is generally json, and there is no need to use the ejs template engine.

...
res.json({
 info:"成功",
 code:1
});
...

I believe you have mastered the method after reading the case in this article. Please pay attention for more exciting things. Other related articles on php Chinese website!

Recommended reading:

How to use PHP static binding in your project

How to use AngularJS to monitor rendering

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