how to send multiple queries in nodejs(see code)

Question

I received some information using html form tags

post={count:[1,2,3]}

the information collected is "post"

exports.log_create_process = function(request, response){
 var _url = request.url;
 var queryData = url.parse(_url, true).query;
 var body = '';
 request.on('data', function(data){
     body = body + data;
 });
 request.on('end', function(){
   var post = qs.parse(body);
   var title = post.title;
   var description = post.description;
   var query=``;
   for(var i=0; i<post.length; i++){
     db.query(`INSERT INTO stock_log(count) VALUES (${post[i}.count);`,function(error, result){
         response.end();
     });
   }
 });
}

My goal is to send queries three times. Assuming the table was initially empty. After the log_create_process has completed the table should look like this:

| count|
|  1   |
|  2   |
|  3   |

boehm_s · Accepted Answer · 2018-08-08 13:02:50Z

In your example, you will receive the response just after the first insert because db.query is asynchronous.

So, if you want to insret your 3 records, you can either insert them with one query, like the following :

const sqlStatement = "INSERT INTO stock_log(count) VALUES ?";
const values = post.count;

db.query(sqlStatement, [values], function (err, result) {
    if (err) response.status(500).send("server error");
    response.end();
});

OR perform multiples queries, but wait until they are finished to respond.
use a db library that offers promises, like node-promise-mysql :

// here we assume that db.query returns a Promise.
const queryPromisesArray = post.count.map(p => db.query(`INSERT INTO stock_log(count) VALUES (${p});`));

Promise.all(queryPromisesArray).then(values => {
  response.end();
});

Hope it helps,
best regards

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