Node failed to connect MySQL without any error prompt - mysql

Question

The problem has been solved, but I'd like to leave this question with a deeper impression. Thanks for everyone!
update
I found something wrong in /src/mysql/index.js, this code
/* this is wrong */
MySqlConnection.connect((error) => {
/* old code */
throw new Error(error.message);
/* new code */
error && new Error(error.message);
});
After modification, i'm connected to MySQL.But i still can't get correct return , i got nudefined...
I tried using node to connect MySQL and operate it, but i failed and get no error message.
I used koa2 and mysql from npm packages.
"koa2": "^2.0.0-alpha.7",
"mysql": "^2.17.1",
My MySQL version is 8.0
I encapsulates a function to connect mysql, i'm sure that MySQL's configuration is useless.
/* /src/mysql/index.js */
const MySqlConnection = require("./mysql.index");
/**
* connnect mysql
* #param {string} sqlStatement sql statement
* #param {object} params some required parameters
* #param {function} callback if success
*/
const MySqlOperator = (sqlStatement, params, callback) => {
MySqlConnection.connect((error) => {
throw new Error(error.message);
});
MySqlConnection.query(sqlStatement, params, (error, result, fieldValues) => {
try {
callback && callback(result, fieldValues);
} catch {
throw new Error(error.message);
}
});
MySqlConnection.end();
MySqlConnection.destroy();
};
module.exports = MySqlOperator;
and i use it like that
const MySqlOperator = require("./src/mysql/MySql");
// These three fields are all char types
const sql = "INSERT INTO users(userUuid, userName, userPwd) values(1111，2222，3333);";
MySqlOperator(sql, {}, (error, result, fliedValues) => {
if (error) {
console.log(error.message);
} else {
/* here is undefined... */
console.log(result, fliedValues);
}
});
App.listen(ServerPort, () => {
// eslint-disable-next-line no-undef
console.log("start success");
});
After I executed node index.js, node told me that he had successfully started, and terminal output start success, but the MySQL plug-in did not work and there was no error message.What can I do to successfully insert this data into MySQL?

Answer 1

Firstly, you say this:
// These three fields are all char types
const sql = "INSERT INTO users(userUuid, userName, userPwd) values(1111，2222，3333);";
So I would advise you to respect types and modified this as:
const sql = "INSERT INTO users(userUuid, userName, userPwd) values('1111'，'2222'，'3333');";
And I think you have also a mistake in this part of /src/mysql/index.js file:
try {
callback && callback(result, fieldValues);
} catch {
throw new Error(error.message);
}
Your original callback function accepts three arguments: (error, result, fliedValues) and you pass there your DB result as an error and because I suppose your query result will be without error (as undefined), then console.log(result, fliedValues); writes undefined.