Develop Reference

firestore getDocuments().size() != getDocumentChanges().size()

I query my firestore db with a complex query
.whereIn(gender_node, getInterestedIn())
.whereGreaterThanOrEqualTo(birthdate_year_node, getShowAgeMax() + 1)
.whereLessThanOrEqualTo(birthdate_year_node, getShowAgeMin())
but I run into an IndexOutOfBoundException, because getDocuments().size() is not equal to getDocumentChanges().size().
I can't find anything in the documentation, does anybody know when or why getDocuments().size() != getDocumentChanges().size() ?
I assumed there would be a DocumentChange for every Document.
It doesn't happen every time, which makes it hard to debug.
There are 7 test documents and getDocuments().size() is always 7, but getDocumentChanges().size() is sometimes 5. Always seems to be the number 5, as far as I have seen.

getDocument().size() and getDocumentChanges().size() are two different methods.
The getDocumentChange().size() returns the list of documents that
changed since the last snapshot.
The getDocument().size() returns
the list of documents.
The details about these methods can be found out in the documentation section.
Suppose, if you have 7 documents and there are changes on 2 documents since last snapshot, then getDocument().size() would be 7( including the newly added or modified documents) here and getDocumentChanges().size() would always refer to the number of changed documents, which in this case is 2.
And hence is the condition,
getDocument().size() ! = getDocumentChanges().size()
true.

Is it possible that you have an extra paranthese closed in this line? (just after birthdate_year_node)
.whereLessThanOrEqualTo(birthdate_year_node),getShowAgeMin())
Otherwise, can you run your code with each one of the 3 "where" clauses seperately so we know which one of the three is creating the issue.

Query GeoHashes in Firetore in range Android

What I'm trying is to get the documents that are in range of a point.
Following the videos and taking a look to the geo-hash library for android, I'm able to get the bounding box and get the necessary geohashes to query in firebase.
As example:
Point -> LatLng(40.4378698,-3.8196205) (Madrid,Spain)
Radius -> 5000meters (5 km)
The boundary box I get is:
[GeoHashQuery{startValue='ezjnh', endValue='ezjns'}, GeoHashQuery{startValue='ezjjs', endValue='ezjj~'}, GeoHashQuery{startValue='ezjq0', endValue='ezjq8'}, GeoHashQuery{startValue='ezjm8', endValue='ezjmh'}]
One I have this list, I call Firebase to retrieve the documents that "match" this criteria:
fun getUpTos(queries: MutableSet<GeoHashQuery>, onSuccessListener: OnSuccessListener<QuerySnapshot>, onFailureListener: OnFailureListener) {
var reference = Firebase.firestore.collection("pois")
queries.forEach { entry ->
reference
.whereGreaterThanOrEqualTo("geohash", entry.startValue)
.whereLessThanOrEqualTo("geohash", entry.endValue)
}
reference.get()
.addOnSuccessListener(onSuccessListener)
.addOnFailureListener(onFailureListener)
}
At this moment I have around 20 Poi's in firebase to start doing the test. All Poi's are in Barcelona and 1 in Madrid.
After doing the query, I'm gettin ALL the poi's, when it was supposed to just return the Madrid poi.
How can I get only the pois that fit the query? It seems is not working properly (or I'm doing obviously something wrong)
Is possible to achieve this type of querys?

Is possible to achieve this type of querys?
Yes, it is possible.
When you are iterating through your queries MutableSet, at every iteration you are creating a new Query object. So you cannot simply call get() outside the loop only once and expect to have all those queries working. What can you do instead, is to add the get() call to every query inside the loop. The type of the object that results is Task<QuerySnapshot>. Add all those Task objects to a List<Task<QuerySnapshot>>. In the end, pass that list of tasks to Tasks's whenAllSuccess(Collection> tasks) method as explained in my answer from the following post:
Android Firestore convert array of document references to List<Pojo>

Firebase Query - how to order by a separate field?

I'm working with an Android App that functions as an instant messaging service, and I'm at the point of pulling the message data through into a RecyclerView. I have my Firebase Query object returning all the messages that match the id of the chat that has been loaded, this is done like so:
Query qChatMessages = mDbRefMessages
.orderByChild("messageChat")
.equalTo(mChatId);
So far so good, and this is returning the collection of messages that I expect. The problem is now that, upon passing them to the RecyclerView to be displayed, they come out in the inverse order of how you would typically expect an instant messenger to display, so the messages are actually getting older as you scroll down the chat.
My message nodes in the database all have a messageTimestamp field associated with them, so this is what I would want to sort the data by. The problem is that I don't seem to be able to find a way of ordering the data by any field other than the one that I'm querying on, or getting the results back from Firebase and subsequently ordering them.
Does anyone know how I can work around this, or if there's some Firebase capabilities I'm not aware of?
Thanks in advance,
Mark

The easiest way is to store an extra piece of data in your message nodes which is the epoch time multiplied by -1: this way you can sort on this field and the query will return the right order.
See this post on how to get the epoch time: how to get the number of seconds passed since 1970 for a date value?
However, note that with your current data structure, you will encounter a problem: you will need to sort on this new data (e.g. with .orderByChild("messageCreationTime")) AND filter for a given mChatId (e.g. with equalTo(mChatId)), which is not possible.
So, you would have to re-structure your database (if this is possible) like this:
- messages
- mChatId
- messageUniqueID <- most probably auto-generated by Firebase
- messageTitle: ....
- messageCreationTime: -1525857044
And you would query by:
Query qChatMessages = databaseReference.child("messages").child(mChatId)
.orderByChild("messageCreationTime");

How to search in Firestore using multiple fields of documents for android?

I'm using a Firebase Firestore for android to store data. I tried to search data from documents.
My Firestore structure is:
Collection (Products) - Document (Auto Generated ID) - Field (NumberOfPeople,OfferStartDate,OfferEndDate,OfferPrice,Location)
I wrote query for search data on those fields.
CollectionReference collectionOfProducts = db.collection("Products");
collectionOfProducts
.whereEqualTo("Location", location)
.whereGreaterThanOrEqualTo("OfferPrice", offerPrice)
.whereLessThanOrEqualTo("OfferPrice", offerPrice)
.whereGreaterThanOrEqualTo("OfferStartDate", date)
.whereLessThanOrEqualTo("OfferEndDate", date)
.get()
I want search result like this: An offer which is between start date and end date, where offer price is greater than equal or less than equal on give price range. This query is not working in android studio.
How to do this in firestore firebase?

According to the official documentation regarding Cloud Firestore queries, please note that there some query limitations:
In a compound query, range (<, <=, >, >=) and not equals (!=, not-in) comparisons must all filter on the same field.
So a Query object that contains a call to both methods:
.whereGreaterThanOrEqualTo("OfferStartDate", date)
.whereLessThanOrEqualTo("OfferEndDate", date)
Is actually not possible, as "OfferStartDate" and "OfferEndDate" are different properties.
The best solution I can think of is to use only one of these method calls and do the other filtering on the client.
Another possible solution might be to use denormalization and duplicate the data
in certain intervals. In this way, you'll always know the time periods and you'll be able to create the corresponding queries.

To the best of my knowledge, Firestore only lets you use where<Greater/Less>ThanOrEqualTo() and where<Greater/Less>Than() a single field and all other filter operations on other fields can only be whereEqualTo().
Some workarounds for your specific case include -
1) Modifying your query to
collectionOfProducts
.whereGreaterThanOrEqualTo("OfferStartDate", date)
.whereEqualTo("Location", location)
.get()
And then performing the subsequent filtering on the result in your app code.
Alternately, you can perform your filter on "OfferPrice" and "Location" in your query and the remaining filters can be applied to the query result.
2) You can use firebase functions or other server code to write logic that performs customized filtering and fetch the result that way.

i was having same issue with this, but i found a work around that takes sometime to write.
lets say you want to search for a particular keyword(in this case the value of a field inside a document), and you want firebase to search multiple field instead of just looking for 1 particular field.
this is what you want to do.
const searchTerm = document.createElement('input')
db.collection('collection').where('field1', '==', `${searchTerm.value}`)
.get()
.then((snapshot) => {
if(snapshot.size === '0'){
db.collection('collection').where('field2', '==', `${searchTerm.value}`)
.get()
.then((snapshot) => {
if(snapshot.size === 0) {
db.collection......and repeat
}
})
}
})
in summary, the above code is basically telling js to search for the term again with a different field if the result of the previous query is 0. I know this solution might not be able to work if we have a large quantity of fields. But for folks out there that are working with small number fields, this solution might be able to help.
I really do hope firestore one day would allow such feature, but here is the code it worked fine for me.
the problem I have now is to allow search input to be able to search without have me to complete the word. I do currently have an idea how this would be, but just need some time to put together.

How to do a simple search in string in Firebase database?

I want to create a simple search in my app, but cannot find anything on interwebs about it, that's more recent than 2014. There must be a better way. There are startAt and endAt functions but they don't work as expected and are case sensitive. How do you guys solve this problem? How can this functionality still not exist in 2016?

In my case I was able to partly achieve a SQL LIKE in the following way:
databaseReference.orderByChild('_searchLastName')
.startAt(queryText)
.endAt(queryText+"\uf8ff")
The character \uf8ff used in the query is a very high code point in the Unicode range (it is a Private Usage Area [PUA] code). Because it is after most regular characters in Unicode, the query matches all values that start with queryText.
In this way, searching by "Fre" I could get the records having "Fred, Freddy, Frey" as value in _searchLastName property from the database.

Create two String variables
searchInputToLower = inputText.getText().toString().toLowerCase();
searchInputTOUpper = inputText.getText().toString().toUpperCase();
Then in the Query set it to:
DatabaseReference reference = FirebaseDatabase.getInstance().getReference().child("Products");//Your firebase node you want to search inside..
FirebaseRecyclerOptions<Products> options =
new FirebaseRecyclerOptions.Builder<Products>()//the Products is a class that get and set Strings from Firebase Database.
.setQuery(reference.orderByChild("name").startAt(searchInputUpper).endAt(searchInputLower + "\uf8ff"),Products.class)
.build();
the "name" it's the node inside the Products Main Node.
the .startAt(searchInputUpper) & .endAt(searchInputLower + "\uf8ff") to make the search as contains all characters that typed in the inputText.getText() that you get.

finally I got it you can use where clause to get you result like SQL
LIKE keyword like% or %like
syntax :
Firestore.collection(collectionName).orderBy(field).where(field, ">=", keyword.toUpperCase()).where(field, "<=", keyword.toUpperCase() + "\uf8ff").get()

I my case used:
var query = 'text'
databaseReference.orderByChild('search_name')
.startAt(`%${query}%`)
.endAt(query+"\uf8ff")
.once("value")
In this way, searching by "test" I could get the records having "Test 1, Contest, One test" as value in 'search' property from the database.

Firebase is noSQL therefore it does not have searches built in like you'll find in SQL. You can either sort by values/key or you can equalto
https://firebase.google.com/docs/database/android/retrieve-data
You can find examples at the link above. That is the latest documentation for firebase.
If you are looking for SQL like searches. Then take a look at elastic search. But that will increase the complexity since you need a platform to put it on. For that i could recommend Heroku or maybe GoogleCloudServers
Here is a blog post about advanced searches with elastic search
https://firebase.googleblog.com/2014/01/queries-part-2-advanced-searches-with.html

This question might be old but there is a documented way of how to achieve this way, It is simple to implement. Quoted:
To enable full text search of your Cloud Firestore data, use a third-party search service like Algolia. Consider a note-taking app where each note is a document:
Algolia will be part of your firebase functions and will do all the searches you want.
// Update the search index every time a blog post is written.
exports.onNoteCreated = functions.firestore.document('notes/{noteId}').onCreate(event => {
// Get the note document
const note = event.data.data();
// Add an 'objectID' field which Algolia requires
note.objectID = event.params.noteId;
// Write to the algolia index
const index = client.initIndex(ALGOLIA_INDEX_NAME);
return index.saveObject(note);
});
To implement the search, the best way is to use instant search - android
Sample Search Image: GIF

The feature you're looking for is called full-text search and this is something most databases (including Firebase) don't provide out-of-the-box because it requires storing the data in a format that's optimized for text search (vs optimized for filtering) - these are two different problem sets with a different set of trade-offs.
So you would have to use a separate full-text search engine in conjunction with Firebase to be able to do this, especially if you need features like faceting, typo tolerance, merchandizing, etc.
You have a few options for a full-text search engine:
There's Algolia which is easy to get up and running but can get expensive quickly
There's ElasticSearch which has a steep learning curve but uber flexible
There's Typesense which aims to be an open source alternative to Algolia.

I don't know about the certainty of this approach but using the firebase version 10.2.6 on android, i get to do something like this:
firebaseDatabase.getReference("parent")
.orderByChild("childNode")
.startAt("[a-zA-Z0-9]*")
.endAt(searchString)
It seems to work well sometimes

Finally joined SO just to answer this.
For anyone coming here from/for the python firestore.client here's a solution that seems to work for me.
It's based on the accepted answer's concept but via the client rather than db.reference() and mixed with the answer from user12750908.
from firebase_admin import firestore
users = db.collection("users")\
.order_by("last_name")\
.where("last_name", ">=", last_name.upper())\
.where("last_name", "<=", last_name.lower() + "\uf8ff")\
.stream()
It works for the simple test I did, but I'll update my answer if I have issues with it later. And just a reminder, this is similar to
LIKE search%
and not
LIKE %search%.
Edit 1
I didn't see any tags for the question, but the title attribute mentions Android so this may not necessarily answer the question directly, but if you have a python API, this should work. I'm unfortunately not sure if there's an equivalent client/db separation in the Android version like there is in the Firebase Admin for Python. I didn't want to delete the answer since I hadn't seen any answers for firestore client during my search for a similar answer and hope it helps anyone else stumbling around.
Edit 09-03-2020 This works a portion of the time it seems. Most of the time I didn't seem to have an issue, but when I applied it to another project I was getting unexpected results. Long story short you may need to replicate how you save the data you're comparing against. For example, you may need to have a field to save the last_name in all caps and another field to save it in all lowercase, then you change the first where clause to compare last_name_upper and the second to compare last_name_lowercase. In my second project so far this seems to yield more accurate results so you may want to give that a try if the previous answer doesn't work well
EDIT 09-07-2020 Previous edit from 09-03-2020 is partially accurate. During my haste of thinking I had it fully resolved I completely forgot firebase doesn't let you use <, >, <=, >= across different fields. You may need to do two queries and merge them, but you'd probably still be reading more docs than you really intend. Doing the comparison against either the upper or lower version with the appropriate search term seems to give the original results expected from the original answer. For example:
.orderBy("last_name_upper")
.where("last_name_upper", ">=", this.searchForm.text.toUpperCase())
.where("last_name_upper", "<=", this.searchForm.text.toUpperCase() + "\uf8ff")

As firebase documentation, firebase doesn't support full text search.
But to do that you can use third-party tools.
Check this link to learn more https://firebase.google.com/docs/firestore/solutions/search