Ajax返回成功，但不更改数据库

Question

I'm developing a small script of js to edit a profile in the way facebook used to be (click a button, edit and save without reloading the page). The problem is that when I run it, the ajax function returns sucess but akes no changes on the database. The function os js is this:

$('.savebtn').click(function(){
            var editdata    = $(".editbox").val();
            var parameter   = $(this).closest("td").find("#parameter").text();

            var datastring  = "data="+editdata+"&parameter="+parameter;

            var $t = $(this);

            console.log(datastring);

            $.ajax({
                type: "POST",
                url: BASE_URL + "/API/update_profile.php",
                data: datastring,
                cache: false,
                success: function()
                {
                    $t.closest('td').find('.curr_value').html(editdata);
                    $t.closest('td').find('.curr_value').hide;
                    console.log(editdata);
                    $(this).prev(".edit").hide();
                    $(this).prev(".curr_value").show();
                    $(this).prev('.edit_link').show();
                    $(this).hide();
                }
            });
        });

(Ignore the $t thing, somehow this works like this, but not if I use $(this))

Ajax executes the code for sucess but doesn't update anything on the database.

The PHP code for the database is:

<?php

include_once("../../config/connect_db.php");
include_once("../../database/cliente.php");

$parameter = $_POST['parameter'];
$data = $_POST['data'];
$id = $_SESSION['id'];

var_dump($_POST);

try {
    updateProfile($parameter, $data, $id);
}
catch (PDOException $e)
{
    echo 'Caught exception: ',  $e->getMessage(), "\n";
}

?>

function updateProfile($parameter, $data, $id)
{
    global $conn;
    $stmt = $conn->prepare("UPDATE biofood.users 
                            SET ? = ?
                            WHERE id = ?");
    $stmt->execute(array($parameter, $data. $id));
}

EDIT: As pointed out, this could be a problem with trying to pass a column name as a parameter. Changed the code to the following, but with no sucess:

function updateProfile($parameter, $data, $id)
{
    global $conn;
    $query = "UPDATE biofood.users 
              SET $parameter = $data
              WHERE id = $id";
    $stmt = $conn->prepare($query);
    $stmt->execute();
}

Answer 1

This line:

$stmt->execute(array($parameter, $data. $id));

I think should be

$stmt->execute(array($parameter, $data, $id));

(notice the comma after $data )

Answer 2

This might not solve your problem, but it might give you a better indication on where your problem is.

First, you are not checking whether it works or not as your updateProfile function returns nothing.

Modify your updateProfile function, so that it returns the number of rows affected. (BTW this is a safer way to write your function. If you can check or limit the value of $parameter prior to calling this function, it will be less prone to SQL injection.)

function updateProfile($parameter, $data, $id)
{
    global $conn;
    $stmt = $conn->prepare("UPDATE biofood.users SET $parameter = ? WHERE id = ?");
    $stmt->execute(array($data, $id));
    return $stmt->rowCount(); // # of rows affected
}

In the script that calls this function, get the value and send it back as a response. We'll send back a JSON.

$response = array();
try {
    $response['success'] = updateProfile($parameter, $data, $id);
} catch (PDOException $e) {
    echo 'Caught exception: ',  $e->getMessage(), "\n";
}

header('Content-Type: application/json');
echo json_encode($response);

In your JavaScript file, make the following change:

$.ajax({
     type: "POST",
     url: BASE_URL + "/API/update_profile.php",
     data: datastring,
     cache: false,
     success: function (data) {
         if (data.success) {
             $t.closest('td').find('.curr_value').html(editdata);
             $t.closest('td').find('.curr_value').hide;
             console.log(editdata);
             $(this).prev(".edit").hide();
             $(this).prev(".curr_value").show();
             $(this).prev('.edit_link').show();
             $(this).hide();
         }
     },
     dataType: 'json'
});