Json 如何在所有子项中查询具有特定值的属性的firebase

我有这样一个数据 struct ，其中TODO按照path/todos/uid进行组织/

{
  "metausers" : {
    "simplelogin:1" : {
      "displayName" : "John Doe",
      "provider" : "password",
      "provider_id" : "1"
    },
    "simplelogin:2" : {
      "displayName" : "GI Jane",
      "provider" : "password",
      "provider_id" : "2"
    }
  },
  "todos" : {
    "simplelogin:1" : {
      "-JUAfv4_-ZUlH7JqM4WZ" : {
        "completed" : false,
        "done" : false,
        "group" : false,
        "private" : false,
        "subject" : "First"
      },
      "-JUAfveXP_sqqX32jCJS" : {
        "completed" : false,
        "done" : false,
        "group" : false,
        "private" : true,
        "subject" : "Second"
      },
      "-JUAfwXnMo6P53Qz6Fd2" : {
        "completed" : false,
        "done" : false,
        "group" : false,
        "private" : false,
        "subject" : "Third"
      }
    },
    "simplelogin:2" : {
      "-JUAg9rVemiNQykfvvHs" : {
        "completed" : false,
        "done" : false,
        "group" : false,
        "private" : false,
        "subject" : "Q first"
      },
      "-JUAgAmgPwZLPr2iH1Ho" : {
        "completed" : false,
        "done" : false,
        "group" : false,
        "private" : false,
        "subject" : "Q second"
      },
      "-JUAgBfF8f7V5R5-XgrY" : {
        "completed" : false,
        "done" : false,
        "group" : false,
        "private" : true,
        "subject" : "Q third"
      }
    }
  }
}

我想查询待办事项，得到private:true的所有记录.可以使用火基(Angular 火)吗？我应该怎么做？或者我应该稍微go 规格化一些，安排好路径/私密，以避免走下待办事项？