Ios 如何在Swift中的Firebase查询中应用多个筛选器？

我正在尝试开发一个应用程序，比如出租车预订和在Firebase上存储数据

但是，我在从Firebase查询RideDetail（历史）数据时遇到了问题

我想在分页表单中获取特定“客户id”的详细信息

我的Firebase数据结构：

{
  "ride_details": {
    "NuEoP2WNPwigsbY1FQy9M150131918189233": {
      "customer_id": "tstebwLlf4OCRdWhNKO9XCO08xY2",
      "destination_address": "New Ranip\nNew Ranip\nAhmedabad\nGujarat 380081\nIndia",
      "destination_lang": 72.55924470000001,
      "destination_latg": 23.0930152,
      "discount": "10%",
      "driver_id": "cIyZQIJ7tsdvF1a9KpRrKucF2o62",
      "drop_time": "2017-07-29 09:12:21 +0000",
      "fare": "13.16 Rs.",
      "payment_time": 150149034812771,
      "pickup_time": "2017-07-29 09:10:38 +0000",
      "priceperkm": "10.00 Rs.",
      "ride_confirm_time": "2017-07-29 09:06:21 +0000",
      "source_address": "Vastrapur\nVastrapur\nAhmedabad\nGujarat\nIndia",
      "source_lang": 72.5293244,
      "source_latg": 23.0350073,
      "tax": "10%"
    },
    "RH0oZ0Ypbkur3wJM3HMvM150147833457957": {
      "customer_id": "aYQFbwLlf4OCRdWhNKO9XCO08xY2",
      "destination_address": "Sarovar Park Plaza Hotels and Resorts Private Limted\nNo 1\nSector 10\nCBD Belapur\nWadala West\nWadala\nMumbai\nMaharashtra 400614\nIndia",
      "destination_lang": 72.8561644,
      "destination_latg": 19.0176147,
      "discount": 0,
      "driver_id": "cIyZQIJ7tsdvF1a9KpRrKucF2o62",
      "drop_time": "",
      "fare": 0,
      "payment_time": 150149034812772,
      "pickup_time": "",
      "priceperkm": 0,
      "ride_confirm_time": "2017-07-31 05:18:54 +0000",
      "source_address": "Smokin Joe's Fresh Pizza\nShop No. 2\n3\nGround Floor\nAbhiman II\nWadala West\nThane West\nMumbai\nMaharashtra 400602\nIndia",
      "source_lang": 72.8561644,
      "source_latg": 19.0176147,
      "tax": 0
    }
  }
}

这里的“付款时间”是付款完成时的时间戳

我想要的回答是：

{
    "RH0oZ0Ypbkur3wJM3HMvM150147833457957": {
      "customer_id": "aYQFbwLlf4OCRdWhNKO9XCO08xY2",
      "destination_address": "Sarovar Park Plaza Hotels and Resorts Private Limted\nNo 1\nSector 10\nCBD Belapur\nWadala West\nWadala\nMumbai\nMaharashtra 400614\nIndia",
      "destination_lang": 72.8561644,
      "destination_latg": 19.0176147,
      "discount": 0,
      "driver_id": "cIyZQIJ7tsdvF1a9KpRrKucF2o62",
      "drop_time": "",
      "fare": 0,
      "payment_type": 150149034812772,
      "pickup_time": "",
      "priceperkm": 0,
      "ride_confirm_time": "2017-07-31 05:18:54 +0000",
      "source_address": "Smokin Joe's Fresh Pizza\nShop No. 2\n3\nGround Floor\nAbhiman II\nWadala West\nThane West\nMumbai\nMaharashtra 400602\nIndia",
      "source_lang": 72.8561644,
      "source_latg": 19.0176147,
      "tax": 0
    },
    "1trcf0Ypbkur3wJM3HMvM150147833457957": {
      "customer_id": "aYQFbwLlf4OCRdWhNKO9XCO08xY2",
      "destination_address": "Sarovar Park Plaza Hotels and Resorts Private Limted\nNo 1\nSector 10\nCBD Belapur\nWadala West\nWadala\nMumbai\nMaharashtra 400614\nIndia",
      "destination_lang": 72.8561644,
      "destination_latg": 19.0176147,
      "discount": 0,
      "driver_id": "cIyZQIJ7tsdvF1a9KpRrKucF2o62",
      "drop_time": "",
      "fare": 0,
      "payment_type": 150149034812778,
      "pickup_time": "",
      "priceperkm": 0,
      "ride_confirm_time": "2017-07-31 05:18:54 +0000",
      "source_address": "Smokin Joe's Fresh Pizza\nShop No. 2\n3\nGround Floor\nAbhiman II\nWadala West\nThane West\nMumbai\nMaharashtra 400602\nIndia",
      "source_lang": 72.8561644,
      "source_latg": 19.0176147,
      "tax": 0
    } 
}

---

我希望在“付款时间”下通过查询orderedBy“payment\u time”传递的特定“customer\u id”的前10条记录。我还想做同样的分页。i、 e.在第二次查询调用中，它必须返回11-20条记录，以此类推。

有两种基本方法可以满足您的要求：

构造一个查询，按

payment\u time

排序，限制只包括前10条记录，然后保留对第10条记录的引用，以便您可以使用

querystartingavalue

过滤器进行后续分页调用

设置firebase cloud函数，使用数据库触发器监听

支付时间

节点，以便每次使用数据库中的值更新您的空sting时，您都会转换数据，以便以这样的方式组织数据，从而使在此处消费您的需求变得微不足道。例如，我将在如下路径组织新数据：

customer\u-ride\u-details/{{customer\u-id}}/{{ride\u-id}

。而且，由于您在用时间戳替换

支付时间

空字符串时触发了该函数。您应该已经订购了钥匙，以便使用。您仍然需要像处理选项1一样管理分页

---

这个问题和评论有一些不同的标准，但让我在一个高层次上讨论它

第一个答案是：不能先查询Firebase的一个子项值，然后再由另一个子项排序

简单查询函数表示：

let query = ridesRef.queryOrdered(byChild: "cust_id").queryEqual(toValue: "cust id 4")

要完成该任务，请查询所需的子数据（在本例中为所有customer id 4节点），然后按代码订购。这里有一个例子

class RideClass {
    var key = ""
    var cust_id = ""
    var pay_time = ""

    init(key: String, cust_id: String, pay_time: String) {
        self.key = key
        self.cust_id = cust_id
        self.pay_time = pay_time
    }
}

var rideArray = [RideClass]()

func populateRideArray() {
    let usersRef = self.ref.child("ride_details")
    let query = usersRef.queryOrdered(byChild: "cust_id").queryEqual(toValue: "cust id 4") 
    query.observeSingleEvent(of: .value, with: { snapshot in 
        for child in snapshot.children {
            let snap = child as! DataSnapshot
            let dict = snap.value as! [String: Any]
            let key = snap.key
            let custId = dict["cust_id"] as! String
            let payTime = dict["pay_time"] as! String
            let ride = RideClass(key: key, cust_id: custId, pay_time: payTime)
            self.rideArray.append(ride)
        }

        for ride in self.rideArray {  //unsorted example
            print(ride.pay_time)
        }

        self.rideArray.sort { $0.pay_time < $1.pay_time } //sort

        for ride in self.rideArray {  //sorted example
            print(ride.pay_time)
        }
    })
}

然后以正确的顺序读取cust id 4节点中的一些代码

    let ridesRef = self.ref.child("ride_details")
    let query = ridesRef.queryOrdered(byChild: "id_time")
                        .queryStarting(atValue: "cust id 4_")
                        .queryEnding(atValue: "cust id 4_\\uf8ff")
    query.observeSingleEvent(of: .value, with: { snapshot in
        for child in snapshot.children {
            let snap = child as! DataSnapshot
            let dict = snap.value as! [String: Any]
            let key = snap.key
            let custId = dict["cust_id"] as! String
            let payTime = dict["pay_time"] as! String
            let ride = RideClass(key: key, cust_id: custId, pay_time: payTime)
            self.rideArray.append(ride)
        }

        for ride in self.rideArray {  //unsorted example
            print(ride.pay_time)
        }
    })

有两点需要注意：

必须迭代快照以维护子序列

---

“\uf8ff”是Unicode中代码级别非常高的字符，因此它包含所有前面的字符。

请将firebase结构作为文本而不是图像发布。图像是不可搜索的，如果我们需要在答案中使用它，则必须重新键入。你能澄清你的疑问吗？您期望的结果是什么？@Jay请再次检查我已编辑的问题。问题仍然不清楚；您想要的数据集是否是具有特定付款类型的特定客户的X个记录数？如果这是正确的，那么您的“回复我想要”不匹配，因为它是针对同一客户的两种不同付款类型。也许是别的原因？订单“付款时间”和“客户id”等于“价值”。不清楚。是否要按付款类型对返回的值进行排序，并且要返回的值是customer\u id=value？要添加的过滤器是动态的还是静态的？。如果是静态的，您将不得不使用JSON数据库结构，这样您就可以开始了。如果是动态的。。您可以对其中一个应用筛选器，然后在前端检索并应用另一个筛选器…听起来您试图在一个查询中组合对

orderBy…

的多个调用，这在Firebase数据库中是不可能的。请看，您可以用结构或查询详细解释。谢谢。你的解决方案对我有效。非常感谢你帮助我。

  "ride_details" : {
    "ride_0" : {
      "cust_id" : "cust id 4",
      "id_time" : "cust id 4_172200",
      "pay_time" : "172200"
    },
    "ride_1" : {
      "cust_id" : "cust id 2",
      "id_time" : "cust id 2_165500",
      "pay_time" : "165500"
    },
    "ride_2" : {
      "cust_id" : "cust id 1",
      "id_time" : "cust id 1_182300",
      "pay_time" : "182300"
    },
    "ride_3" : {
      "cust_id" : "cust id 3",
      "id_time" : "cust id 3_131800",
      "pay_time" : "131800"
    },
    "ride_4" : {
      "cust_id" : "cust id 4",
      "id_time" : "cust id 4_132200",
      "pay_time" : "132200"
    }
  },

    let ridesRef = self.ref.child("ride_details")
    let query = ridesRef.queryOrdered(byChild: "id_time")
                        .queryStarting(atValue: "cust id 4_")
                        .queryEnding(atValue: "cust id 4_\\uf8ff")
    query.observeSingleEvent(of: .value, with: { snapshot in
        for child in snapshot.children {
            let snap = child as! DataSnapshot
            let dict = snap.value as! [String: Any]
            let key = snap.key
            let custId = dict["cust_id"] as! String
            let payTime = dict["pay_time"] as! String
            let ride = RideClass(key: key, cust_id: custId, pay_time: payTime)
            self.rideArray.append(ride)
        }

        for ride in self.rideArray {  //unsorted example
            print(ride.pay_time)
        }
    })