如何在不知道父键的情况下通过特定值查询防火墙数据库

Question

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我想找到电子邮件是amitabh@gmail.com的密钥(例如：-KYNc6XTtavDtsC-VoqIb)

我尝试了许多代码，但没有工作，我得到了完整的数据列表。

这是我的密码：

database = FirebaseDatabase.getInstance();
myRef = database.getReference("members");
myRef.orderByChild("email").startAt(emailId).endAt(emailId);

这就是我要得到的。

DataSnapshot{
  key=members,
  value={
    -KYNYiw5B1d8Brdz5KdR={
      lastname=zxvzxvfsdf44,
      email=fasdfds@rr44,
      firstname=fdafaf44
    },
    -KYNYdX_gZ0tU-AbI1Ab={
      lastname=zxvzxvfsdf,
      email=fasdfds@rr,
      firstname=fdafaf
    },
    -KYNd02QZptRktmR02IH={
      lastname=dfasf,
      email=you@bo.com,
      firstname=amita
    },
    -KYNdlMM4zzlUT9FdSdu={
      lastname=99dfasfs,
      email=99@bos.com,
      firstname=99
    },
    -KYNdBPMqxgSzm1ai92B={
      lastname=dfasfs,
      email=you@bos.com,
      firstname=amitas
    },
    -KYNlYF4OzzCCewJuatt={
      lastname=go2o,
      email=go@to.to,
      firstname=go
    },
    -KYNo7ZvLQeCGm97yUvf={
      lastname=bamio,
      email=samio@ss.com,
      firstname=amio
    },
    -KYNdBRAipnlTYCCUwz6={
      lastname=dfasfs,
      email=you@bos.com,
      firstname=amitas
    },
    -KYNc6XTtavDtsC-VoqI={
      lastname=Sarkar,
      email=amitabh@gmail.com,
      firstname=amitabh
    },
    -KYNcHdlZjUlNSsjKlyW={
      lastname=gjaldga,
      email=ee@ee.com,
      firstname=ami
    }
  }
}

Answer 1

我找到了解决办法：

myRef.orderByChild("email").startAt(emailId).endAt(emailId).addChildEventListener(new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot dataSnapshot, String s) {

        Log.e("onChildAdded", dataSnapshot.toString());
    }
});