I want to retrieve data uid in User table data but for a specific user , I have 2 users, and it seems that it grabs the 2 users uid but I want to grab with i speficy not both of them just one.
Thank You In advance
let specificDatabase = Database.database().reference()
specificDatabase.queryOrdered(byChild: "User/FirstName").queryEqual(toValue: "The user first name")
specificDatabase.observeSingleEvent(of: .value) { (snapShot: DataSnapshot) in
for child in snapShot.children {
print(snapShot.key)
}
}
Firebase Data Structure
"User" : {
"ez8sTAsqXTWfnuzizUXU69VS4qM2" : {
"FirstName" : "other",
"LastName" : "Martin",
"uid" : "ez8sTAsqXTWfnuzizUXU69VS4qM2"
},
}
"Data" : {
"ez8sTAsqXTWfnuzizUXU69VS4qM2" : {
"-Ll7jUYg6BxRAhWPLskg" : {
"Name" : "other Martin",
"Data1" : "data"
},
"-Ll7jW_elQIPTLESwDYD" : {
"Name" : "other Martin",
"Data1" : "data "
}
},
}
You're telling Firebase to order each child node of the root by its User/FirstName property and then filter on that. Since the child nodes of the root don't have a property at that path, the query returns no results.
Instead you want to order/filter each child node of /User by itsFirstName property, which you can do with:
let specificDatabase = Database.database().reference(withPath: "User")
specificDatabase.queryOrdered(byChild: "FirstName").queryEqual(toValue: "other")
Related
I am attempting to populate a table view with values from my Firebase database. I was able to use queryOrdered on the root of my database to get the children I required, as seen here:
func oneTimeInit() {
databaseRef?.queryOrdered(byChild: "Seasons").observe(.value, with:
{ snapshot in
for item in snapshot.children {
self.seasons.append(Season( snapshot: item as! DataSnapshot))
}
self.seasonsTableView.reloadData()
})
}
But now I am trying to get the children of the next node in my database. I tried to do this by calling queryOrdered on the child of the root but I'm not getting any data. Here is my code:
func oneTimeInit() {
databaseRef?.child("Seasons").queryOrdered(byChild: season.name).observe(.value, with:
{ snapshot in
for item in snapshot.children {
print("ITEM VALUE: \(item)")
self.races.append(Race(snapshot: item as! DataSnapshot))
}
self.racesTableView.reloadData()
})
}
The Database contains, at its highest level, Cross Country Seasons, which each contain Cross Country Races, which each contain results. Im able to populate the Seasons table but not the Races table, and so on.
Heres the Json structure of my database:
{
"Seasons" : {
"XC 2018" : {
"NCAA DI West Regional" : {
"Men" : {
"Results" : {
"Aaron BRUMBAUGH" : {
"finishTime" : "31:59.0",
"lapTimes" : [ "5:05.1", "10:43.3", "11:07.1", "5:03.5" ],
"name" : "Aaron BRUMBAUGH",
"position" : "118",
"splitTimes" : [ "5:05.1", "15:48.4", "26:55.5", "31:59.0" ],
"team" : "Santa Clara",
"year" : "SR"
},
"Addison DEHAVEN" : {
"finishTime" : "29:47.8",
"lapTimes" : [ "4:58.2", "10:14.0", "10:04.1", "4:31.5" ],
"name" : "Addison DEHAVEN",
"position" : "7",
"splitTimes" : [ "4:58.2", "15:12.2", "25:16.3", "29:47.8" ],
"team" : "Boise State",
"year" : "SR"
},
"Ahmed MUHUMED" : {
"finishTime" : "30:08.1",
"lapTimes" : [ "4:58.6", "10:14.6", "10:08.5", "4:46.4" ],
"name" : "Ahmed MUHUMED",
"position" : "29",
"splitTimes" : [ "4:58.6", "15:13.2", "25:21.7", "30:08.1" ],
"team" : "Boise State",
"year" : "SO"
},
As of now there is only one "Season" (XC 2018) with one "Race" (NCAA D1 West Regional). I'm trying to get a reference to all of the "Races" under the "Season" XC 2018.
The variable season.name would contain the value "XC 2018". With my second one time init I am trying to look at the children of "XC 2018".
I am trying to use a query to retrieve data of student who are only 4 years old from my database but i cant figure out how to use Firebase to query the age (The array in each child).
{
"student" : {
"-Kv2RVDDsI-v6V7g_LBn" : [ {
"name" : "sam",
"age" : "6"
}, {
"name" : "tom",
"age" : "4"
}
],
"-hguyu-v6V7g_LBn" : [ {
"name" : "Tim",
"age" : "12"
}, {
"name" : "tom",
"age" : "4"
}
]
}
}
This is my code but it does no return anything.
ref.child("student").queryOrdered(byChild: "age").queryEqual(toValue: 4).observe(.childAdded, with: { (snapshot) in
let value = snapshot.value
print(value)
}) { (error) in
print(error.localizedDescription)
}
However, if i remove the queryOrdered(byChild: "age") it works.
Thanks.
You are referencing "Student" when actually your JSON database format child path name is "Students".
Also make sure that you are querying by key. Refer to the Firebase documentation to see how to query by key. I don't understand your structure though why you have 2 children per key.
Why not have a new key for each child?
Each user has a conversation node, each time a new conversation has a new message I need to update both conversation nodes for the two user involved in the conversation, I want just to update the "lastMessage" and "tinestamp" fields here is my try:
let fanoutObject = [userPath : dataToUpdate,
otherUserPath : dataToUpdate]
K.FirebaseRef.root.updateChildValues(fanoutObject)
where the paths for each user is:
"/users/{userID}/conversations/{conversationID}"
and the dataToUpdate:
let dataToUpdate:[String:AnyObject] = ["timestamp" : message.timestamp,
"lastMessage": message.textBody]
Result:
The node conversations for each user is updated BUT other fields in the conversation node are removed !
the conversation node fro each user is:
"conversations" : {
"{conversationID}" : {
"lastMessage" : "your name ?",
"seen" : true,
"timestamp" : 1467849600000,
"with" : {
"country" : "US",
"firstName" : "John",
"profileImage" : "https://..."
}
}
}
note that the node conversations is inside a node user which is an element inside the root node users
and after update it's :
"conversations" : {
"{conversationID}" : {
"lastMessage" : "your name ?",
"timestamp" : 1467849600000,
}
}
but I was expecting just to update the two values and keep others ?
According to docs my code should works:
updateChildValues Update some of the keys for a defined path without
replacing all of the data.
It's a bit hard to parse your code, but most likely it's the behavior of updateChildValues() that is confusing you.
When you call updateChildValues(), the Firebase server will loop over the object that you pass in. For each path in there, it will replace the entire value at that path with the value from that you passed in.
So if your current JSON is:
{
"Users": {
"uidForUser1": {
"name": "iOSGeek",
"id": 2305342
},
"uidForUser2": {
"name": "Frank van Puffelen",
"id": 209103
}
}
And the update is (in JSON format, the lingua franca of the Firebase Database):
{
"users/uidForUser2/name": "puf",
"users/uidForUser1/name": "My actual name"
}
Your resultant JSON will be:
{
"Users": {
"uidForUser1": {
"name": "My actual name",
"id": 2305342
},
"uidForUser2": {
"name": "puf",
"id": 209103
}
}
But if you send the following update:
{
"users/uidForUser1": {
"name": "My actual name"
},
"users/uidForUser2": {
"name": "puf"
}
}
The resulting JSON will be:
{
"Users": {
"uidForUser1": {
"name": "My actual name"
},
"uidForUser2": {
"name": "puf"
}
}
Update
To update two fields in the same object, but leave the other fields unmodified:
{
"path/to/object/field1": "new value",
"path/to/object/field2": "new value2"
}
Alternatively, you can update the lastMessage and timeStamp data by replacing the old values by providing full path :
let lastMessagePath = "/users/{userID}/conversations/{conversationID}/lastMessage"
let lastTimeStampPath = "/users/{userID}/conversations/{conversationID}/timestamp"
K.FirebaseRef.child(lastMessagePath).setValue(message.timestamp)
K.FirebaseRef.child(lastTimeStampPath).setValue(message.textBody)
I'm trying to do an inner join on a FIRDatabaseQuery object.
below is the database structure. I have some posts that are linked to post-comments. I am trying to get all the posts that a specific user added a comment on:
{
"posts" : {
"-KIycKhZU55dmKnHbbxv" : {
"author" : "John Doe",
"body" : "This is a post test",
"title" : "test",
"uid" : "SHaH36BLwgPvwgi9cDmRnsnONFB2"
},
"-KIyg_ks1O5QL4_4dfq_" : {
"author" : "Jane Doe",
"body" : "This is a post test",
"title" : "test2",
"uid" : "x5leSBGArnd10JilD9YDyNBNfZ03"
},...
}
"post-comments" : {
"-KIycKhZU55dmKnHbbxv" : {
"-KIycMyL0Vy1BHVdI4zc" : {
"author" : "toto",
"text" : "test",
"uid" : "SHaH36BLwgPvwgi9cDmRnsnONFB2"
},
"-KIyg_ks1O5QL4_4dfq_" : {
"author" : "toto",
"text" : "test",
"uid" : "SHaH36BLwgPvwgi9cDmRnsnONFB2"
}
},...
}
in SQL this will be translated into a inner join query similar to:
Select * from post inner join post-comments on post-id where post-comments.uid = "user id"
Does anybody know how o get something similar to an inner join in firebase?
Thanks a lot,
Yacine
You may want to consider
"posts" : {
"-KIycKhZU55dmKnHbbxv" : {
"author" : "John Doe",
"body" : "This is a post test",
"title" : "test",
"uid" : "SHaH36BLwgPvwgi9cDmRnsnONFB2"
"commented_by"
"SHaH36BLwgPvwgi9cDmRnsnONFB2": true
Then you can simply query for
posts.child("commented_by/uid").queryEqualToValue(true)
or, change the post-comments around to better match the queries you want to do:
"post-comments" : {
"-KIycMyL0Vy1BHVdI4zc" : {
"author" : "toto",
"post_data":
post_id: "-KIycKhZU55dmKnHbbxv",
post_title: "test"
"text" : "test",
"uid" : "SHaH36BLwgPvwgi9cDmRnsnONFB2"
},
That makes the query a snap as the post-comments node can be queried for the uid which return all of the post_id's of the posts they commented on. It wouldn't return the post itself, however, you may just be looking for the title so you can populate a list. Once the user taps it clicks it you can retrieve the actual data.
You will need to work with nested firebase calls. You can find a javascript example in this question but your swift code should look like the following:
ref.child("posts").observeEventType(.ChildAdded, withBlock: { (snapshot) in
if let postId = snapshot.key as! String {
let commentsRef = ref.child("post-comments")
commentsRef.child(postId).queryOrderedByChild("uid").queryEqualToValue(userId).observeSingleEventOfType(.Value, withBlock: { (snapshot) in
for child in snapshot.children.allObjects as [FDataSnapshot] {
print(child.value)
}
}) { (error) in
print(error.localizedDescription)
}
}
})
Situation: I have a database with users, users can have friends and friends are linked to current user model as userID. So when I'm loading user data I'm receiving also a list of firebase IDs of his friends.
Question: Is there any way to receive firebase snapshot with all this users at once? Haven't found any suitable solution - .child() is linking directly with one object, queryOrderedByChild() and queryOrderedByValue() doesn't seem to make such requests.
Will be grateful for any advice.
Edit: Database structure:
{
"Users": {
"user_id_first" : {
"user_info" : {
"name": "name",
"age": "age"
},
"friends": {}
},
"user_id_second" : {
"user_info" : {
"name": "name",
"age": "age"
},
"friends": {}
},
"user_id_third" : {
"user_info" : {
"name": "name",
"age": "age"
},
"friends": {
"user_id_first" : true,
"user_id_second" : true
}
}
}
}
There are list of friend IDs, which are actually IDs of firebase users. All I need is to retrieve information for these users in one firebase snapshot (i.e. use one reference) without creating new reference for each friend like
myDBRef.child("Users").child("friend_id")
Use for loop to access all the friendsId :-
let parentRef = FIRDatabase.database().reference().child("Users")
parentRef.child(FIRAuth.auth()!.currentUser!.uid).child("friends").observeEventType(.Value, withBlock: {(snapshot) in
if snapshot.exists(){
if let friendsDictionary = snapshot.Value as! NSMutableDictionary{
for each in friendsDictionary as! [String : AnyObject]{
let friendsId = each.0 as! String
parentRef.child(friendId).observeEventType(.Value, withBlock: {(friendDictionary)
if let friendsInfo = friendDictionary.Value as! NSMutableDictionary{
//retrieve the info
}
})
}
}
}
})