Firebase查询双嵌套

鉴于firebase中的数据结构,我想运行一个查询来检索博客'efg'.我此时不知道用户ID.

{Users :
     "1234567": {
          name: 'Bob',
          blogs: {
               'abc':{..},
               'zyx':{..}
          }
     },
     "7654321": {
          name: 'Frank',
          blogs: {
               'efg':{..},
               'hij':{..}
          }
     }
}

Frank van Pu.. 32

在火力地堡API只允许您过滤孩子深一级(或用已知的路径与它)orderByChild和equalTo方法.

因此,无需修改/扩展当前的数据结构,只留下检索所有数据的选项并在客户端过滤它:

var ref = firebase.database().ref('Users');
ref.once('value', function(snapshot) {
    snapshot.forEach(function(userSnapshot) {
        var blogs = userSnapshot.val().blogs;
        var daBlog = blogs['efg'];
    });
});

{Blogs:
     "abc": "1234567",
     "zyx": "1234567",
     "efg": "7654321",
     "hij": "7654321"
}

var ref = firebase.database().ref();
ref.child('Blogs/efg').once('value', function(snapshot) {
    var user = snapshot.val();
    ref.child('Blogs/'+user+'/blogs').on('value, function(blogSnapshot) {
        var daBlog = blogSnapshot.val();
    });
});