Data not collected correctly from JSON object using JQUERY

Question

I'm trying to create a function that selects data from database in server-side and sets it as value of textbox in client-side. It works fine in server-side, but in client side, if I write a console.log for the data, it shows undefined and I can't figure out why. Thanks a lot !

Server-side:

app.post('/id', function(req,res) {

    var data = req.body;
    var id = data.id;
    console.log(id);
    var query = "SELECT * FROM Control WHERE id=" +id;
    connection.query(query, function(error, result) {
            console.log(result);
            res.json(result);
    });
});

Client-side:

function select()
            {
                var id = $('#nr_reg').val();
                $.ajax({
                    type: 'post',
                    data: JSON.stringify(data),
                    dataType: 'json',
                    url: '/id',
                    data : {
                        id: id
                    },
                    success : function(data){           
                        console.log(data);                          
                        var id = data.id;
                        $('#optic').val(id);

                    },
                    error: function(err){
                        console.log(err);
                    }

                }); 
            }

The result from server after the query:

5 //this is the id which is correct
[ { id: 5,
    data: '',
    kw: '6',
    nr_articol: '279630-99',
    proiect: 'AUHE',
    optic: '0',
    electric: '',
    reelectric: '',
    smd: 'on',
    scurt_smd: '0',
    incomplete_smd: '',
    bile: '',
    val: '',
    scurt_val: '',
    incomplete_val: '',
    nivel_cositor: '',
    greseli_smd: '',
    lipsa_smd: '',
    invers_smd: '',
    plantare_manuala: '',
    componente_lipsa: '',
    componente_inversate_1: '',
    greseli_hotbar: '',
    lipire_hotbar: '',
    greseli_asamblare: '',
    componente_inversate_2: '',
    greseli_imprimare: '',
    componente_inversate_3: '',
    greseli_aspect: '',
    fire_lovite: '',
    componente_inversate_4: '',
    casaste: '',
    reparate: '',
    Total: '0' } ]

what does the serverside object look like and what about the client object you are receiving? and what do you expect it to look like? — gulty
– gulty, Commented Sep 22, 2015 at 16:24
you have two data options in the jquery ajax call. data: JSON.stringify(data) and data: {id: id} — Overmachine
– Overmachine, Commented Sep 22, 2015 at 16:24
I have updated the first post to see how the console shows the result after the query. — Ezekiel
– Ezekiel, Commented Sep 22, 2015 at 16:27

Marcus Abrahão · Accepted Answer · 2015-09-22 16:38:31Z

1

Try use data[0]

Since your outcome is: [{ id: 5,.... }] it means a object in an array. in order to data.id work, your outcome should be {id: 5,.....}. So try this:

            function select()
            {
                var id = $('#nr_reg').val();
                $.ajax({
                    type: 'post',
                    data: JSON.stringify(data),
                    dataType: 'json',
                    url: '/id',
                    data : {
                        id: id
                    },
                    success : function(data){           
                        console.log(data);                          
                        var id = data[0].id;
                        $('#optic').val(id);

                    },
                    error: function(err){
                        console.log(err);
                    }

                }); 
            }

edited Sep 22, 2015 at 16:38

answered Sep 22, 2015 at 16:30

Marcus Abrahão

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1 Comment

Marcus Abrahão Over a year ago

you are welcome! the [] means it is in an array, that is why i guessed the data[0]

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