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[英]How can I get real time update on a webpage using nodejs and socket.io from a mysql database?
[英]How can I update data using NodeJS?
我想將結果預測更新到數據庫 mysql,但數據無法保存在數據庫中。
const periode = _.get(row, "periode", new Date());
const prediction =
b0 +
b1 * Number.parseFloat(_.get(row, "x1", 0)) +
b2 * Number.parseFloat(_.get(row, "x2", 0));
const sql = `UPDATE performance SET prediction_result="${prediction}" WHERE periode="${periode}"`;
db.query(sql, (error, results, fields) => {
if (error) {
console.error('An error occurred while executing the query')
throw error
}
})
我收到這樣的錯誤:
throw err; // Rethrow non-MySQL errors
ReferenceError: connection is not defined
你能幫我解決這個問題嗎?
您的代碼中應該有類似的內容。
var mysql = require('mysql');
var db= mysql.createConnection({
host: "localhost",
user: "yourusername",
password: "yourpassword"
});
db.connect(function(err) {
if (err) throw err;
console.log("Connected!");
});
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