Javascript Node.js MySQL 模块 - 抛出错误；// 重新抛出非 MySQL 错误；
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Node.js MySQL module - throw err; // Rethrow non-MySQL errors;
提问by Null
today I tried node.js mysql snippet from w3schools:
今天我尝试了 w3schools 的 node.js mysql 片段：
var mysql = require('mysql');
var con = mysql.createConnection({
host: "localhost",
user: "roots", // WRONG USER
password: ""
});
con.connect(function(err) {
if (err) throw err;
console.log("Connected!");
/*Create a database named "mydb":*/
con.query("CREATE DATABASE mydb", function (err, result) {
if (err) throw err;
console.log("Database created");
});
});
I wanted to learn how to handle mysql errors, because my app require mysql. But after I started app.js file this error showed up: 
我想学习如何处理 mysql 错误，因为我的应用程序需要 mysql。但是在我启动 app.js 文件后，这个错误出现了：
Why can't I throw an error?
为什么我不能抛出错误？
采纳答案by EMX
I wanted to learn how to handle mysql errors, because my app require mysql.
我想学习如何处理 mysql 错误，因为我的应用程序需要 mysql。
To catch the errors you throw, try with the following snippet :
要捕获错误throw，请尝试使用以下代码段：
con.on('error', function(err) {
console.log("[mysql error]",err);
});
回答by Rizal Amrullah
change you're database conn like this
像这样改变你的数据库连接
var mysql = require('mysql');
var connection = mysql.createConnection({
host : 'example.org',
user : 'bob',
password : 'secret',
database : 'secret'
});
connection.connect(function(err) {
if (err) {
console.error('error connecting: ' + err.stack);
return;
}
console.log('connected as id ' + connection.threadId);
});