How to update data in Parse IOS - ios

Question

I am facing an issue when trying to update data in Parse.
Here is my code that i am using.
PFQuery *query = [PFQuery queryWithClassName:#"GameScore"];
[query whereKey:#"name" equalTo:#"Username"];
[query getFirstObjectInBackgroundWithBlock:^(PFObject *item, NSError *error)
{
if (!error)
{
[item setObject:#500 forKey:"Score"];
}
[item saveInBackgroundWithBlock:^(BOOL succeeded, NSError *itemError)
{
if (!error)
{
NSLog(#"Score is updated");
}
else
{
NSLog(#"Error in updating: %#",error.description);
}
}];
}
else
{
NSLog(#"Error in getting Score: %#",error.description);
}
}];
This code works only when i create a new PFObject and then try to update it.
But,when i exit my app and then try to update the score again,i am unable to update the data.It throws this error..
Error in getting Score: Error Domain=Parse Code=101 "No results matched the query." UserInfo={error=No results matched the query., NSLocalizedDescription=No results matched the query., code=101}
It works again,if i create a new PFObject.
Please help,i am new to Parse and am still try to understand it.
Thank you.

Answer 1

You need to use findObjectsInBackgroundWithBlock instead of getFirstObjectInBackgroundWithBlock as the latter can only be used if there's at least 1 object.
Reference - Parse Questions

Answer 2

You could also use the PFQuery's count method. If the count is >= 1, use getFirstObjectInBackgroundWithBlock, otherwise display a message / handle that case however you'd like.
Other options include storing the objectId of the GameScore object associated with a player on their user object, creating an object without data using the objectId, then fetching it. Or simply use a pointer, but that can do weird things when saving / querying / fetching.