Parse Pointers and Relations

Question

So right now I have two classes. A User class, and a UserUpdates class. the UserUpdates class is used to handle friendRequests, and friends, and what not. I have a field in my UserUpdates class called friendsArray, I want to have a field in my User class called friendsArray as well, that will just point to the UserUpdates friendsArray so I dont have to do a seperate query.

So in summary, what I want to accomplish is have a field in my User class, that updates automatically or points to the friendsArray in the other class (UserUpdates)

The friendsArray is simply an array of strings which are usernames

How can I accomplish this using parse's api?

Marius Waldal Marius Waldal · Accepted Answer · 2014-04-06T10:47:23

It is not possible to point a property of another object; you can only point to the object containing that property (the friendsArray).

If what you're trying to accomplish is to easily get the friendsArray from the UserUpdates class, you can do that like this, if the User class has a pointer to the UserUpdates object:

PFQuery *userQuery = [PFUser query];
// add constraints to get the correct user
[userQuery includeKey:@"UserUpdates"]; // ensures the UserUpdates object is downloaded with the User object

NSArray *results = [userQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        PFUser *theUser = [objects lastObject]; // If the constraints returns only 1 object
        PFObject *userUpdates = theUser[@"UserUpdates"];
        NSArray *friends = userUpdates[@"friendsArray"]; // Now you have the friends array
    }];

It might be possible to chain the last calls together like this, but I am unsure. Try it out:

NSArray *friends = theUser[@"UserUpdates"][@"friendsArray"];

Parse Pointers and Relations

2 Answers