Nodejs Mysql Select Count nested loop insert query - mysql

Question

I am new in nodejs and mysql.
I am have an array of objects that i get from post and want to insert it to mysql database.
If the data already exist then run the update query to database.
The problem is Insert query not loop the entire array. it just insert the last entry of Array. Here my code:
Array Data:
bukukasData
[{transactionid: '562018965521',
tanggal: '2018-06-05',
kodeakun: 0, item: 'Saldo',
debit: 100000, credit: 0,
saldo: 100000},
{transactionid:'562018595664',
tanggal:'2018-06-05',
kodeakun: 0,
item: 'Test Data',
debit: 0,
credit: 5000,
saldo:95000}]
NodeJS Query
app.post('/api/addbukukas', function(req, res) {
let bukukasData = req.body.bukukasData;
var status = '';
for (var i = 0; i < bukukasData.length; i++) {
var transactionid = req.body.bukukasData[i].transactionid;
var kodeakun = req.body.bukukasData[i].kodeakun;
var item = req.body.bukukasData[i].item;
var debit = req.body.bukukasData[i].debit;
var credit = req.body.bukukasData[i].credit;
var saldo = req.body.bukukasData[i].saldo;
var tanggal = req.body.bukukasData[i].tanggal;
db.query('SELECT COUNT (*) AS rowCount FROM bukukas WHERE transactionid = ?', [req.body.bukukasData[i].transactionid], function(error, result) {
var rows = result[0].rowCount;
if (rows > 0) {
db.query('UPDATE bukukas SET transactionid=?, kodeakun=?, tanggal=?, item=?, debit=?, credit=?, saldo=? WHERE transactionid = ?', [transactionid, kodeakun, tanggal, item, debit, credit, saldo, transactionid],
function(err, result) {
if (err) {
status = 'Update Gagal';
} else {
status = 'Update Success';
}
})
} else {
db.query('INSERT INTO bukukas (transactionid, kodeakun, tanggal, item, debit, credit, saldo) VALUES (?,?,?,?,?,?,?)', [transactionid, kodeakun, tanggal, item, debit, credit, saldo], function(err, insertresult) {
if (err) {
status = 'Insert Gagal';
} else {
status = "insertresult";
}
})
}
})
}
console.log(status);
return res.json({ status: status });
});
With this code the only data that getting inserted to database just the last data in array. How can i insert all the data in Array to database?
Thanks

Answer 1

Use let instead of var. That will avoid this problem.
The source of this problem is, that in JavaScript the for-loop loops through the variable i and starts bukukasData.length times the db query. The parameter is given as reference. Since the loop iterates very fast, the first sql statement ist started with i set to the last value and all db-statements are executed with i set to bukukasData.length. let was introduced to JavaScript to fix problems like this. With let it will create a copy of the variable in the background.