Parse query using pointers

Question

For simplicity sake, I have two classes Location and Program. Location has objectId and name, while Program has objectId, name and location (which is a pointer to Location ObjectId). When a user selects a location, how do I return the associated programs in a query? The following code doesn't work right now.

let pointer = PFObject(withoutDataWithClassName: "location", objectId: passedLocationID!) //passedLocationID is a string containing the ObjectId from the selected location    

let query = PFQuery(className:"Program")
query.whereKey("location", equalTo: pointer.objectId!)
query.findObjectsInBackgroundWithBlock {
    (objects: [PFObject]?, error: NSError?) -> Void in
    if error == nil {
        if let objects = objects {
            for object in objects {
                self.programName.append(object["name"] as! String)
                self.programID.append(object.objectId! as String)
            }
        }
    } else {
}

This query prints the following error to the console "pointer field location needs a pointer value"

What would the correct code be to return the associated programs?

EDIT

I have found a solution, but it seems like overkill. Two queries to Parse, I feel like this should be accomplished using only 1 query.

let firstQuery = PFQuery(className: "Location")
firstQuery.whereKey("objectId", equalTo: passedLocationID!)
    
let secondQuery = PFQuery(className: "Program")
secondQuery.includeKey("location")
secondQuery.whereKey("location", matchesQuery: firstQuery)
secondQuery.findObjects.......

Craig.Pearce · Accepted Answer · 2016-01-02 07:43:36Z

2

So I found an answer.

When I pass the location to the program view controller, I need to pass it as a PFObject.

var passedLocationID: PFObject?

And then just a simple query works.

let newQuery = PFQuery(className: "Program")
newQuery.whereKey("location", equalTo: passedLocationID!)

answered Jan 2, 2016 at 7:43

Craig.Pearce

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Santiago Prieto · Accepted Answer · 2019-05-06 18:27:33Z

0

Adding the correct answer updated for Swift 3+ in case someone is searching:

guard let query = ProgramModel.query(), let pointerQuery = LocationModel.query() else {
   // Your parse class isn't set up correctly. Handle error.
   return
}

// You can also use other parameters like `notEqualTo` or `containedIn`.
pointerQuery.whereKey("objectId", equalTo: passedLocationId)

// The important line is the one below, which calls the pointer query:
query.whereKey("location", matchesQuery: pointerQuery)
query.includeKey("location")
query.findObjects... or query.countObjects...

answered May 6, 2019 at 18:27

Santiago Prieto

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Parse query using pointers

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