I'm trying to get firebase data from a node which uid must start with a passed string.
I tried a code but I always get the same data. The database data is as following:
And I'm using the following code:
var ref = firebase.database().ref("restaurantes/history");
ref.orderByKey().startAt(userUID).once("child_added", function(snapshot) {
snapshot.forEach(child => {
if(child.key == "orders")
{
console.log(child.val());
_.each(child.val(), (value, key) => {
arrtmp.push(value)
})
}
})
If user is "FKQLlqa" I should get the history data shown in the picture. If I user is "abc" I shouldn't get any data. But I always get the data shown in the picture. Should I use another way of querying? Or I should use a key field inside orders and payments data?
Regards!
Try the following:
var ref = firebase.database().ref("restaurantes/history");
ref.child(userUID).once("value", function(snapshot) {
if (snapshot.exists()) {
console.log(snapshot.val());
}
else {
console.log("different user");
});
This will check if the snapshot that contains the userId (added as a parameter in the child() method), already exists in the database then you will be able to retrieve the data under the userId.
For reference:
https://firebase.google.com/docs/reference/js/firebase.database.DataSnapshot#exists
Peter's answer is the correct solution. I'm merely adding this for completeness.
When you call orderBy... on a Firebase reference, the database orders all child nodes on the key/value/child that you specify.
If you then subsequently call startAt(...) on the query, it finds the (first) node that starts with that value and starts returning all results from there. So if you start at FKQLlqa, it will start returning keys at FKQLlqa and then return all keys after it.
If you want to return the child node(s) with a specific key/value/child, you'd use equalTo(...). So:
ref.orderByKey().equalTo(userUID).once("child_added", function(snapshot) {
...
But as Peter said already, this is just a more expensive way to look up a child with a known key. I highly recommend using his better approach: ref.child(userUID).once("value".
Related
this is really frustrating me I hope you kind people can assist me.
I have a firebase firestore db that stores info about properties and cities. All properties contain a key:value pair called location_city. It is a string that stores the City that the property resides in.
I have made a dropdown box on a webpage with a list of available cities. The idea is to dynamically display properties from the selected city, by means of the .where() method. The third parameter accepted by the method is the string you want to query against.
I want to pass the text value of the dropdown list into the query.
Here's my code:
let selectedCityViewHomes;
function getDropdownSelection(sel) {
selectedCityViewHomes = sel.options[sel.selectedIndex].text;
selectedCityViewHomes.toString();
}
db.collection('Homes')
.where('location_city', '==', selectedCityViewHomes)
.get()
.then(snapshot => {
snapshot.docs.forEach(doc => {
renderHome(doc);
});
});
The query method only seems to work if you manually enter a string into the parameter and does not seem to allow you to pass a variable (which is a string) into the method.
I have tried concatenating "'" either side to mimic 'Manchester', for example and this did not work either.
TIA
Charlie
EDIT: I found where i had gone wrong, it was an issue of scope i think. I fixed it by creating a function which wrapped the db.collection code and passed in the variable as an argument.
const updateHomesViewHomes = (input) => {
db.collection('Homes').where('location_city', '==', input).get().then((snapshot) => {
homesViewHomes.innerHTML = "";
snapshot.docs.forEach(doc => {
renderHome(doc);
});
});
};
Thanks for the replies, hope this helps someone.
I have created a realtime database in Firebase and have some data looking like this inside a key called "firms":
I got the user key and wants to find the key where the user is placed. I have tried something like this:
let userkey = 'the key that I have for the user'
ref.child('firms').child('users').orderByChild('user').equalTo('userkey').on("value",
function(snapshot) {
console.log(snapshot.val());
});
Is there something that i'm missing?
You have to do as follows:
ref
.child('firms')
.orderByChild('users/user')
.equalTo(userkey) // Warning: in your question you do equalTo('userkey') with quotes
.on('value', function (snapshot) {
console.log(Object.keys(snapshot.val())[0]);
});
As explained in the doc, you need to specify the relative path to the nested child in your orderByChild() call.
This is my first app project using Google Cloud Functions & Firebase. I'm trying to find away to get a single value of the array that I'm returning and compare it to a set variable and if it matches, update another child's value in that same account.
My App users can add records to the database under their login/user_id that is stored in the database. I'm trying to get a list of the "RecordName" that is a child under that login/user_id that every user has stored in their account.
So basically every "RecordName" in the entire database. When I want to run specials for those records, I need to match the name of that record to the name of the record I have on special and if there is a match, update another child value under that user's account ("special" = true.). This way, when they load their app next time, I have it highlighting that record so they know it's on special.
When I use..
const ref = admin.database().ref(`/store`);
...with the following code...
ref.on('value', function(snapshot) {
// puts ALL items of the object into array using function ..
console.log(snapshotToArray(snapshot));
});
... and the function...
function snapshotToArray(snapshot) {
var returnArr = [];
snapshot.forEach(function(childSnapshot) {
var item = childSnapshot.val();
item.key = childSnapshot.key;
returnArr.push(item);
});
return returnArr;
};
... I get the entire array just as it is in the database:
-store
-{ones_users_id}
-recordname: value1
-special: false
-{anothers_users_id}
-recordname: value2
-special: false
ect. ect.
If my record on special is called, "Newbie Record", what would be the best way to take out every individual value for the key: "recordname" from the array, compare each one to var = "Newbie Record" and if they match, update the value of the key: "special" to be true?
I'm new to JSON and NodeJS, I've been searching on here for answers and can't find exactly what I'm looking for. Your feedback would be very helpful.
It sounds like you're looking to query your database for nodes that have "recordname": "Newbie Record" and update them.
An easy way to do this:
const ref = admin.database().ref(`/store`);
const query = ref.orderByChild("recordname").equalTo("Newbie Record");
query.once('value', function(snapshot) {
snapshot.forEach(function(child) {
child.ref.update({ special: true })
});
});
Main differences with your code:
We now use a query to read just the nodes that we want to modify.
We now use once() to read the data only once.
We loop over the children of the snapshot, since a query may result in multiple nodes.
We use the reference of each child and then update its special property.
I recommend reading a bit more about Firebase queries in the documentation.
No matter what I do I can't seem to figure out a way to access the child "onSite", which shows as being there when I log snapshot.val(), but I cannot figure out how to access it.
Code:
firebase.database().ref().child("users").orderByChild('facebook_id').equalTo(fbID).once("value").then(function(snapshot) {
console.log(snapshot.val());
console.log(snapshot.child("onSite").val());
});
Here is the response:
It shouldn't be null, it should be false. I can't do child("4mUUjF...").child("onSite").val() because I don't know what the ID is before the query. Using an each loop doesn't work, it only loops through the first level, which is the ID.
Use the key of the object
Get the snapshot val and then find the key with the Object.keys method. This will allow you to then get inside the snap. Once there it's a simple matter of accessing the values like any other object.
firebase.database().ref().child("users").orderByChild('facebook_id').equalTo(fbID).once("value").then(function(snapshot) {
let snap = snapshot.val();
let key = Object.keys(snap)[0]
console.log(snap[key].onSite);
})
When you execute a query against the Firebase Database, there will potentially be multiple results. So the snapshot contains a list of those results. Even if there is only a single result, the snapshot will contain a list of one result.
Your code needs to handle the list, by using Snapshot.forEach():
firebase.database().ref().child("users").orderByChild('facebook_id').equalTo(fbID)
.once("value").then(function(result) {
result.forEach(function(snapshot) {
console.log(snapshot.val());
console.log(snapshot.child("onSite").val());
});
});
see jsfiddle: http://jsfiddle.net/237ur2tf/14/
coinref.orderByChild("uuid").equalTo("xx")...
Query works fine when there is a match in the database.
When there is no match, neither the callback nor error function is called.
Am I doing something wrong?... What would be the way around this?.
Many thanks.
Pat/
That is the expected behavior. The relevant snippet from your fiddle is slightly longer:
// Get by child uuid AND uuid exists
coinsRef.orderByChild("uuid")
.equalTo("4D4B2118-0435-439C-BA7C-99B9BD0DA7F4")
.on('child_added', function(snapshot) {
This code says that "when there is an (existing or new) child added to this query, call me with its snapshot". Since there is no child, the child_added event doesn't fire.
If you want to check if there is a value, you should use a value event:
// Get by child uuid AND uuid exists
coinsRef.orderByChild("uuid")
.equalTo("4D4B2118-0435-439C-BA7C-99B9BD0DA7F4")
.on('value', function(snapshot) {
console.log("found Coin: 4D4B2118-0435-439C-BA7C-99B9BD0DA7F4");
If you want to do anything with the specific coin, you'll need to forEach() in the callback:
snapshot.forEach(function(child) {
console.log("The coin has value: "+child.val());
})
Is there any reason why you can't store the coins by their uuid? It sounds like that is already a universally unique identifies; so if it is possible to store them with that key, the lookup would be a lot cheaper:
coinsRef.child("4D4B2118-0435-439C-BA7C-99B9BD0DA7F4")
.on('value', function(snapshot) {
console.log("The coin has value: "+snapshot.val());
})