firebase - Is there any limit on number of indexes -


i new firebase.we have application creates notifications users.the same notification might delivered multiple users. have structured data follows optimize data storage cost:

notifications {     message1     {         tiltle:"abc",         desc:"desc"         user1 : true         user2 : true         user3 : true     }      message2     {         tiltle:"efg",         desc:"desc"         user1 : true         user2 : true         user3 : true     } }

the users query messages using orderbychild("<userid>").equalto(true).

we cannot use array of users attached messages user can mark message read in case need remove user message.

now problem see queries slow. further see warning firebase says use indexes while performing queries on child nodes. number of users keep increasing, mean need create index whenever new user signs up.

given situation, wondering if there limit on number of indexes can created?also impact of creating large number of indexes?

when using nosql you'll end modeling data use-cases need in application. current use-case "get messages user", not ideal data structure. you're making database consider messages each query. while may normal practice in relational databases, nosql it's better model differently.

given use-case "get messages user", data model makes sense:

notifications: {     message1: {         tiltle:"abc",         desc:"desc"         user1 : true         user2 : true         user3 : true     }     message2: {         tiltle:"efg",         desc:"desc"         user1 : true         user2 : true         user3 : true     } }, messages_per_user: {     user1: {         message1: true         message2: true     }     user2: {         message1: true         message2: true     }     user3: {         message1: true         message2: true     } }

now if want load messages user, do:

ref.child('messages_per_user').child('user1').on('value', function(snapshot) {     snapshot.foreach(function(messagesnapshot) {         ref.child('notifications').child(messagesnapshot.key).once('value', function(notificationsnapshot) {             console.log(notificationsnapshot.val());         })     }); });

this way database can directly access correct nodes , ignore else.

recommended reading:


Comments

Post a Comment

Popular posts from this blog

sublimetext3 - what keyboard shortcut is to comment/uncomment for this script tag in sublime -

Image
i have script tag in code, keyboard shortcut comment/uncomment script tag in sublime. after selecting script open , close tag. <script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> </script> i pressing ctrl + shift + / , getting this /*<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> </script>*/ also pressed ctrl + / , got this // <script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> // </script> instead of <!-- <script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> </script> --> script open , close tag in 2 lines not in 1 line , not have spaces too. for mac,high light lines want comment. hold 'command , / ' commented. for windows: high line or select lines ,then hold ctrl + / if not work: ...
Read more

post - imageshack API cURL -

i credentials correct. when send image through form this:(action="http://api.imageshack.com/v2/images/"). working fine when tried send $ch = curl_init($url); failed. code: enter code here <form action="" method="post" enctype="multipart/form-data"> select image upload: <input type="file" name="file" id="file" multiple> <input type="text" name="auth_token" id="auth_token" value="xxxxxxxxxxxxxxxx"> <input type="text" name="api_key" id="api_key" value="xxxxxxxxxxxxxxx"> <input type="submit" value="upload image" > </form> $url = ' http://api.imageshack.com/v2/images/ '; $temp = $_files["file"]['tmp_name']; echo $temp."<br>" ; $ch = curl_init($url); curl_setopt($ch, curlopt_post, true); curl...
Read more

dataset - MPAndroidchart returning no chart Data available -

i having problems mpandroidchart. adding temperature , humidity data chart, displays "no chart data available". here can see bug is? super grateful! //create data //set size of data int size = list.size(); if (size > 24){ size = 24;} //create lists form temp , hum arraylist<entry> temps = new arraylist<entry>(); arraylist<entry> hums = new arraylist<entry>(); //fill list temp values (int = 0; < size; i++){ entry value = new entry(math.round(list.get(list.size()-size + i).temp), (size-i)); temps.add(value); } //fill list hum values (int = 0; < size; i++){ entry value = new entry(math.round(list.get(list.size()-size + i).hum), (size-i)); hums.add(value); } ...
Read more