Node JS - Node js MySQL Update - Node - Node JS tutorial - webnode
Update Table
- You can update existing records in a table by using the "UPDATE" statement in mysql
Example
Overwrite the address column from "Valley 345" to "Canyon 123":
var mysql = require('mysql');
var con = mysql.createConnection({
host: "localhost",
user: "yourusername",
password: "yourpassword",
database: "mydb"
});
con.connect(function(err) {
if (err) throw err;
var sql = "UPDATE wikitechy_customers SET address = 'Canyon 123' WHERE address = 'Valley 345'";
con.query(sql, function (err, result) {
if (err) throw err;
console.log(result.affectedRows + " record(s) updated");
});
});
Notice the WHERE clause in the UPDATE syntax:
- The WHERE clause specifies which record or records that should be updated. If you omit the WHERE clause, all records will be updated!
- Save the code above in a file called "wikitechy_db_update.js" and run the Node JS Tutorial File:
Run "wikitechy_db_update.js"
C:\Users\Your Name>node wikitechy_db_update.js
Ouput
1 record(s) updated
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The Result Object
- When executing a query, a result object is returned.
- The result object contains information about how the query affected the table.
- The result object returned from the example above looks like this:
{
fieldCount: 0,
affectedRows: 1,
insertId: 0,
serverStatus: 34,
warningCount: 0,
message: 'Rows matched: 1 Changed: 1 Warnings: 0',
protocol41: true,
changedRows: 1
}
- The values of the properties can be displayed like this:
Example
Return the number of affected rows:
console.log(result.affectedRows)
Ouput
1