How to update objects using Cloud Code? - json

Question

I am using Parse Cloud Code for retrieving JSON data from external API. JSON data are updated every 2 min.
To accomplish this, I am using Cloud Job to run my method every 2 minutes to keep data fresh. Also, I am storing whole JSON data to Parse.
When I run this code for the first time everything works well, but... when code runs for second, third or fourth time instead of updating objects it creates the new ones.
How to update objects instead of creating the new ones, when there are some data?
Code:
Parse.Cloud.define("getCars", function(request, response) {
var promise = new Parse.Promise();
var Cars = Parse.Object.extend('Cars');
var query = new Parse.Query(Cars);
query.find().then(function (results){
Parse.Cloud.httpRequest({
method: 'GET',
url: urlLink,
success: function(httpResponse) {
var stations = new Array();
var data = JSON.parse(decodeURIComponent(escape(httpResponse.text))); // utf-8 decode
for (var i = 0; i < data.length; i++) {
var Cars = Parse.Object.extend('Cars'),
car = new Cars(),
content = data[i];
car.set('number', content.number);
car.set('name', content.name);
car.set('address', content.address);
car.set('position', content.position);
car.set('status', content.status);
cars.push(station);
};
Parse.Object.saveAll(cars, {
success: function(objects) {
promise.resolve();
},
error: function(error) {
alert("Error: " + error.code + " " + error.message);
promise.reject(error.message);
}
});
},
error: function(error) {
alert("Error: " + error.code + " " + error.message);
promise.reject(error.message);
}
});
});
return promise;
});
SOLUTION
I have finally found the solution. Maybe this will be useful for other people who are facing the same problem.
I added a simple if statement which checks query result. If query does not return data, new object is created, otherwise: old object is filled with new information and saved into database.
station = (results == 0) ? new Stations() : results[i];

Answer 1

you are createting new object car = new Cars(), every time.instead find with objectId and in success response you will get ParseObject list(array).
update first parseObject from that list