使用 AngularJS 在 Firebase 实时数据库中使用 .indexOn 规则过滤数据

Question

我正在使用如下所示的 FireBase 实时数据库结构。并想要提取所有具有 red 颜色的 model。

FireBase

{
  "models": {
    "model1": {
      "modelName": "model 1",
      "color": {
        "red": true,
        "blue": true,
        "green": true
      }
    },
    "model2": {
      "modelName": "model 2",
      "color": {
        "yellow": true,
        "blue": true,
        "green": true
      }
    },
    "model3": {
      "modelName": "model 3",
      "color": {
        "red": true,
        "yellow": true,
        "pink": true
      }
    },
    "model4": {
      "modelName": "model 4",
      "color": {
        "red": true,
        "orange": true,
        "white": true
      }
    }
  }
}

我尝试使用下面的查询但没有得到预期的结果。

AngularJS

let fbRef = firebase.database().ref('models');

fbRef
    .orderByChild('red')
    .equalTo(true)
    .once('value', function(data){
      console.log('result : ', data);
    });

FireBase 规则

{
  "rules": {
    ".read": true,

    "$modelID": {
      ".read": true,
      ".indexOn": ["red", "blue", "green", "orange", "pink", "white", "yellow"]
    }

  }
}

预期结果

{
  "model1": {
    "modelName": "model 1",
    "color": {
      "red": true,
      "blue": true,
      "green": true
    }
  },
  "model3": {
    "modelName": "model 3",
    "color": {
      "red": true,
      "yellow": true,
      "pink": true
    }
  },
  "model4": {
    "modelName": "model 4",
    "color": {
      "red": true,
      "orange": true,
      "white": true
    }
  }
}

Answer 1

您应该在'color/red'之前订购，如下：

  fbRef
    .orderByChild('color/red')
    .equalTo(true)
    .once('value', function(data) {
      //Use the val() method of the DataSnapshot
      console.log('result : ', data.val());
      //Or loop over children
      data.forEach(function(childSnapshot) {
        var childKey = childSnapshot.key;
        var childData = childSnapshot.val();
        console.log('childKey : ', childKey);
        console.log('childData : ', childData);
      });
    });

因为你得到了 DataSnapshot, you may either use the val() method to get the result as an object or use forEach() 到 "enumerates the top-level children in the DataSnapshot"。两种方式的区别之一是 "the ordering of data in the JavaScript object returned by val() is not guaranteed to match the ordering on the server" 如文档中所述。

使用 AngularJS 在 Firebase 实时数据库中使用 .indexOn 规则过滤数据

Filter data with .indexOn rules in Firebase realtime database with AngularJS

firebase

ionic-framework

firebase-realtime-database

angular

ionic4