swift - 如何进行探测器 PFRelation 查询？Parse.com

Question

我已经成功地建立了关系。现在我不知道如何查询它我可以在网站上看到数据我可以看到它相互链接

这是我如何制作“链接”PFRelation

 var query = PFQuery(className:"Profile")
    let objectID = data.valueForKey("objectId") as String?
    query.getObjectInBackgroundWithId(objectID) {
        (rodObj1: PFObject!, error: NSError!) -> Void in
        if error == nil {
            let dateFormatter = NSDateFormatter()
            dateFormatter.dateFormat = "MMM-d-yyyy HH:mm:ss zzz"
            let str1 = dateFormatter.stringFromDate(NSDate())
            var dateFromString1 = dateFormatter.dateFromString(str1)




            var profil = PFObject(className: "SwitchColor")
            profil["Rod"] = dateFromString1
            println("Profil = ********\(profil)")
            profil.saveEventually()
            let rod: PFRelation = rodObj1.relationForKey("SwitchColor")
            rod.addObject(profil)
            println("rodObj = *********\(rod)")
            rodObj1.saveEventually()
        }
    }

这是我如何进行查询“这不起作用”

 let rodobj: PFObject = PFObject(className: "Profile")
            let relationRod: PFRelation = rodobj.relationForKey("SwitchColor")
            let query: PFQuery = relationRod.query()
            query.orderByDescending("createdAt")
            query.findObjectsInBackgroundWithBlock{(objQ: [AnyObject]!, error: NSError!) -> Void in
                if let staffObjects = objQ as? [PFObject] {
                    for staff in staffObjects {
                       self.countObj.addObject(staff)
                        staff.pin()
                        self.barChart.reloadData()
                        dispatch_async(dispatch_get_main_queue(), {
                            self.tableView.reloadData()
                            self.refreshControl.endRefreshing()
                        })
                        println("countObj: \(self.countObj.count)")

                    }
                }
            }

Answer 1

关系的问题是您不能使用现有的数据字段，如果有关系字段，则必须创建仅对该行可见的新字段。因此，在此之前，查询不会向您显示任何内容。