CODEWITHSUNDEEP
objective-cparse-platform
Josue Espinosa
Josue Espinosa

Reputation: 5089

Access object of to-many relationship

I have an object with a to-many relationship. It goes Workout<-->>Workout Score. If I have the workout score, how can I access the workout? I am using Parse.com.

Assuming workoutScore is a PFObject, and has been retrieved, I have a relationship called whichWorkout on it. The object returned is the workout, however I cannot access it's properties. Am I doing something wrong?

// Assuming this score has been retrieved by a PFQuery
PFObject *workoutScore;
PFObject *actualWorkout = workoutScore[@"whichWorkout"];
// Now when I try to access a property of actualWorkout, I can't
NSString *name = actualWorkout[@"name"];

If I just query for the actual workout, the same code works. Is there any way to access properties of objects retrieved via pointer relationships using Parse?

Upvotes: 0

Views: 90

Answers (3)

WCByrne
WCByrne

Reputation: 1569

If you are running a query on the workoutScore you should use [query include:@"workout"]. This will pull the object that is being pointed to (the actualWorkout) and get everything you need in one call

PFQuery query = [PFQuery queryWithClassName:@"WorkoutScore"];
[query includeKey:@"workout"];
[query findAllInBackground....

The other option is to call fetch on the actual workout. This will be a second call after you have fetched the workoutScore. If you know you are going to need the workout probably better to get it during the query with the include.

PFObject *actualWorkout = workoutScore[@"whichWorkout"];

// There are asynchronous versions of fetch too
// which would be recommended
[actualWorkout fetch]; 

// actualWorkout will now have its data.
NSString *name = actualWorkout[@"name"];

Upvotes: 1

Fernando Mazzon
Fernando Mazzon

Reputation: 3591

If the many to many relationship is a PFRelation, you'll have to query it as a second step

PFRelation *relation = [parseObject relationForKey:@"relationName"];
PFQuery *query = [[relation query] findObjectsInBackground:...];

If the many to many relationship is just an array of pointers, you need to tell the query to include the actual data:

[workoutScoreQuery includeKey:@"whichWorkout"];

Upvotes: 1

danh
danh

Reputation: 62676

If WorkoutScore has a back pointer to Workout (it looks like it does from your code, called whichWorkout), then it's easy. When querying WorkoutScore, use includeKey: to aggressively fetch the related object:

[workoutScoreQuery includeKey:@"whichWorkout"];

Upvotes: 1

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