Node.js - Slack Bot Example with Database

//Connect Database;
let mysql = require('mysql');
let conn  = mysql.createConnection({
    host: "DBHOST",
    user: "DBUSER",
    password: "DBPASSWD",
    database: "DBNAME"
});

let Botkit = require('botkit');
let controller = Botkit.slackbot();
let bot = controller.spawn({
    token: "<Slack API Token>"
});

bot.startRTM(function(err,bot,payload){
    if(err){
        ShowError("Cloud not Connection to Slack",err);
    }
});

conn.connect(function (err) {
    if(err){
        ShowError("Not Connected Database! ",err);
    }
    console.log("Connected Database");

    conn.query ("SELECT * FROM Command_list",function (err,result) {
        if(err){
            ShowError("Database Query Error",err);
        }
        result.forEach(function (data) {
            controller.hears(data.question.split(','),["direct_message","direct_mention","mention","ambient"],function(bot,message){
                bot.reply(message,data.answer);
            })
        });
        controller.hears([".*" ],["direct_message","direct_mention","mention","ambient"],function(bot,message){
            bot.reply(message,'죄송합니다. 아직 등록된 답변이 없습니다.\n개발지원실에 답변등록요청 해주세요.');
        });
    });
});

function ShowError(command,err){
    throw new Error(`${command} \nSee Error: ${err}`);
}