内部查询解析

Question

我正在尝试链接用户创建的票证，该票证链接到收件人，但是我什么也没回来，我能够从票证表中获取票证，但是内部查询的匹配似乎没有链接。脱离解析文档，我尝试使用内部查询来用作链接或桥，如下所示：

let innerQuery = PFQuery(className:"Tickets")
        let query = PFQuery(className: "Messages")

        //get all tickets for current user
        innerQuery.whereKey("user", equalTo: PFUser.current()?.objectId as Any)
        //objectId is ticketId in tickets table
        innerQuery.includeKey("objectId")
        //match to ticketId in messages table
        query.whereKey("ticketId", matchesQuery: innerQuery)

        do {
            let returnedObjects = try query.findObjects()
            for object in returnedObjects {
                let sender = object["sender"] as? String
                }
            }
        } catch {

        }

Answer 1

首先，当我们需要在Parse Server中进行内部查询时，我们会将列另存为Pointer对象。因此，这里您需要将Message表中的ticketId列另存为Tickets类的指针类。您可以这样保存它：

let pointerObj = [“__type": "Pointer", "className": "Tickets", "objectId": "yourClassObjectId"]
messagePraseObj.setValue(pointerObj, forKey: “ticketId")

之后，您可以使用以下代码完成任务。我在项目中使用了它。我使用了iOS SDK版本1.17.3和Swift 4。

    let innerQuery = PFQuery.init(className: "Tickets")
    innerQuery.whereKey("user", equalTo: PFUser.current()?.objectId as Any)

    let query = PFQuery.init(className: "Messages")
    query.whereKey("ticketId", matchesQuery: innerQuery)
    query.includeKey("ticketId")

    query.findObjectsInBackground { (returnedObjects, error) in
        if error == nil && returnedObjects != nil {
            for object in returnedObjects! {
                let ticket = object.value(forKey: "ticketId") as! PFObject
                let sender = ticket.value(forKey: "user") as? String ?? ""
                print("User ID: \(sender)")
            }
        }
    }

有关更多信息：https://docs.parseplatform.org/ios/guide/#relational-queries

希望它会帮助您。