Fetch pointer key if needed - objective-c

Question

I have a PFObject and a few of the keys contain pointers. Sometimes I'm not including these in the original query. How do I fetch these for an existing object? Do I have to form a whole new PFQuery?

Answer 1

The accepted answer is incorrect. The OP said that sometimes the related objects are not included in the original query, and asks if another query is necessary.
includeKey is for use in the original query. If the objects are not included, the correct approach is to use fetchIfNeeded:
https://parse.com/docs/ios/api/Classes/PFObject.html#//api/name/fetchIfNeeded
PFObject *department = user[#"department"];
// If includeKey was not used for department in the original query, department is now only a stub pointing to the actual object.
[department fetchIfNeededInBackgroundWithBlock:^(PFObject *object, NSError *error) {
NSString *departmentName = department[#"name"];
}];

Answer 2

Use includeKey: on any pointer keys you want included in the query.
PFQuery * query = [PFQuery queryWithClassName:#"SomeParseClass"];
[query includeKey:#"SomePointerKey"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
PFObject * firstOb = objects[0];
PFObject * pointerObject = firstOb[#"SomePointerKey"];
}
}];
If you already have an object, you can fetch the pointer object. If it doesn't have a reference to the object, you would have to stack fetches:
if (ob[#"SomePointerKey"]) {
// ob already has pointer to object
PFObject * pointerOb = ob[#"SomePointerKey"];
[pointerOb fetchInBackgroundWithBlock:^(PFObject *object, NSError *error) {
if (!error) {
// pointerOb ready here!
}
}];
}
else {
// ob is missing pointer data, fetch it!
[ob fetchInBackgroundWithBlock:^(PFObject *object, NSError *error) {
PFObject * pointerOb = object[#"SomePointerKey"];
[pointerOb fetchInBackgroundWithBlock:^(PFObject *object, NSError *error) {
if (!error) {
// pointerOb ready here!
}
}];
}];
}