In this application i am adding data in mongodb which is working fine but at same time i need to implement Mysql. So when i register a user it should get save in Mongodb and in Mysql. My Code for Mysql Data Connection is sucessfull but data pushing is not happening(Mysql). Can anyone help me out yr. Thank you very much.

    const {Sequelize} =require('sequelize');
    const mysql= require('mysql');
    var path1 = require('path');
    var root_path = path1.dirname(require.main.filename);
    var models  = require(root_path '/models');
    
    router.post("/users", function(req, res) {
                console.log("First In");
                var user_id=req.query.user_id
                var flag;
                var userData = [];
                var body_data =req.body.data;
                //Mysql Start
                const con = mysql.createConnection({
                    host: 'localhost',
                    user: 'root',
                    password: 'root',
                    database: 'tcexam'
                  });
                  
                  con.connect((err) => {
                    if(err){
                      console.log('Error connecting to Db',err);
                      return;
                    }
                    console.log('Connection established');
                  });
                  models.userMysl.find({
                    email: body_data.email.toLowerCase()
                    })
                    console.log("Email---------->>>",email);
                     .then(function(country){
                                models.userMysl.create({
                                    name: body_data.user_firstName,
                                  lastname : body_data.user_lastname,
                                  mother_name : body_data.motherName,
                                   surname : body_data.Surname,
                                   email: body_data.userEmail.toLowerCase(),
                                  username:body_data.user_name,
                                   password:body_data.user_password,
         
                                 }).then(function(user) {
                                      if(error){
                                                console.log("Error",error);
                                        }else {
                                           
                                          res.send({ 
                                                 status: 200,
                                                 data:userData
                                             });
                                      }
                                   });
                                });
                            });
                       //Mysql End
                userModel.find({
                    "role": req.query.user_type
                }).then(function(users) {
                    users.forEach(user => {
                        
                        if(user.doc_id==''){
                            var user = {
                                id: user._id,
                                name: user.fullName,
                                status: user.status,
                                role: user.role,
                                email:user.email,
                                lastLoginDate: user.lastLoginDate,
                                lastLoginTime: user.lastLoginTime,
                                flag:'0'
                            }
                            userData.push(user);
                        }
                        else{
                             var usr = {
                            id: user._id,
                            name: user.fullName,
                            picture: `${filelink}/api/usersData/download?document_id=${user.doc_id}`,
                            status: user.status,
                            role: user.role,
                            email:user.email,
                            lastLoginDate: user.lastLoginDate,
                            lastLoginTime: user.lastLoginTime,
                            flag:'1'
                        }
                    
                        userData.push(usr);
                    }
                    })
                    res.send({
                        status: 200,
                        data: userData
                    })
                })

    "use strict";
    
    module.exports = function(sequelize, DataTypes) {
        var userMysql = sequelize.define("tce_users", {
            user_name: DataTypes.STRING(100),
            user_password: DataTypes.STRING,
            surname: DataTypes.STRING(100),
            user_email: DataTypes.STRING(100),
            user_firstName:DataTypes.STRING(100),
            user_lastname:DataTypes.STRING(100),
            user_birthdate:DataTypes.String(17),
            user_birthplace:Datatypes.STRING(100),
            user_regnumber:DataTypes.STRING(100),
            user_ssn:DataTypes.STRING(100),
            user_level:DataType.STRING(100),
            user_verifycode:Datatypes.STRING(100)
        });
    return userMysql;
    };

CodePudding user response：

Since, Node JS is single threaded, after insertion into mysql line of code executes before establishment of connection with mysql db. Somehow connecting with mysql require time therefore next block code executes before connection happen. Firstly, you need to change approach where you need to connect mysql,

1. Connection string probably should not be in the post api itself, it's needs to be connect when application starts using some config utility.
2. Either you can choose promise to resolve the execution of insertion into mysql or can use async await approach to insert the data after mysql connection established.