Node.js, multiple MySQL insertions

Question

i want to do multiple MySQL insertions in a specefic ordner for my server-client-application.

var con = createDatabaseConnection();

function createDatabaseConnection() {
return (mysql.createConnection({
        host: // hostIp,
        user: // user,
        password: //pw,
        database: //databasename
    });
}

function writeFoo(fooObject) {
   var sql = // prepare sql insert for fooObject;
   con.query(sql, function (err) {
      // ? Is inserted data ready to use ?
   }
});

function writeBar(barObject) {
   var sql = // prepare sql insert for barObject;
   con.query(sql, function (err) {
      // ? Is inserted data ready to use ?
   });
});

// Both arrays containing an unpredictable amount of objects
var fooArray = [];
var barArray = [];

The crucial point is that I have to be absolutely sure, that the fooObjects in the fooArray are inserted before the barArray gets inserted. Because the SQL INSERT statement which is used in writeBar() contains a SELECT statement which has to find the data inserted in writeFoo(). And at any moment an event could happen (client sends data that needs to be inserted), that would need this functionality too.

The real situation is a bit more complex, but i think that's the main problem at the moment.

here is good lib caolan.github.io/async

Mirodil
– Mirodil

2017-06-22 17:06:11 +00:00
Commented Jun 22, 2017 at 17:06 — Mirodil
– Mirodil, Commented Jun 22, 2017 at 17:06

Mihai Iorga · Accepted Answer · 2017-06-22 17:22:40Z

You can chain them in a promise, this way you will make sure every call is in order, ex:

var con;
function createDatabaseConnection() {
    return new Promise(function (resolve, reject) {
        mysql.createConnection({
            host: hostIp,
            user: user,
            password: pw,
            database: databasename
        }, function(err, res){
            if(err) reject(err);
            else resolve(res);
        });
    });
}

function writeFoo(fooObject) {
    let sql = fooObject;
    return new Promise(function (resolve, reject) {
        con.query(sql, function (err, res) {
            if(err) reject(err);
            else resolve(res);
        });
    });
}

function writeBar(barObject) {
    let sql = barObject;
    return new Promise(function (resolve, reject) {
        con.query(sql, function (err, res) {
            if(err) reject(err);
            else resolve(res);
        });
    });
}

createDatabaseConnection()
    .catch(function (error) {
        // connection failed
        // log info
        console.error(error);
        process.exit(0);
    })
    .then(function (res) {
        con = res;
        return writeFoo(fooObject);
    })
    .catch(function (error) {
        // writeFoo(fooObject) failed
        // log info
        console.error(error);
        process.exit(0);
    })
    .then(function () {
        return writeBar(barObject);
    })
    .catch(function (error) {
        // writeBar(barObject) failed
        // log info
        console.error(error);
        process.exit(0);
    });

Christian4423 · Accepted Answer · 2017-06-22 17:03:05Z

0

Not going to say ORM's are always best but http://docs.sequelizejs.com/ works well with node. There is a bulk insert option right in there.

answered Jun 22, 2017 at 17:03

Christian4423

1,8072 gold badges16 silver badges26 bronze badges

Collectives™ on Stack Overflow

Node.js, multiple MySQL insertions

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related