How to query firebase for property with specific value inside all children

Question

I have this data structure, where todos are organized to follow path /todos/uid/

{   "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"       }     }   } } 

and i would like to query todos to get all records with private:true. Is this possible using firebase (angularfire) and how should i do it ? Or should i denormalize a bit more and arrange path /private to avoid of walking down todos ?

Answer 1

Assuming you have the uid, this should be straightforward with the following:

var uid = "simplelogin:1"; var todosRef = new Firebase("https://yourdb.firebaseio.com/todos/" + uid); var privateTodosRef = todosRef.orderByChild("private").equalTo(true); var privateTodos;  privateTodosRef.on("value", function(response) {   privateTodos = response.val(); }); 

This should return an object with all of this user's private todos, organized by their todo key (ie "-JUAfv4_-ZUlH7JqM4WZ". If you'd like to use Angularfire you can wrap this in a $firebaseArray and assign it as follows:

$scope.privateTodos = $firebaseArray(privateTodosRef); 

Here's a reference for more info on complex queries, and as mentioned in the other responses there are some nice optimizations that can be done with priorities and restructuring.

Happy coding!