Firestore get all documents in collection android

When you delete a document, Cloud Firestore does not automatically delete the documents within its subcollections. You can still access the subcollection documents by reference. Non-existent ancestor documents appear in the consolebut they do not appear in query results and snapshots. If you want to delete a document and all the documents within its subcollections, you must do so manually.

For more information, see Delete Collections. To delete specific fields from a document, use the FieldValue. To delete an entire collection or subcollection in Cloud Firestore, retrieve all the documents within the collection or subcollection and delete them. If you have larger collections, you may want to delete the documents in smaller batches to avoid out-of-memory errors.

firestore get all documents in collection android

Repeat the process until you've deleted the entire collection or subcollection. Deleting a collection requires coordinating an unbounded number of individual delete requests.

If you need to delete entire collections, do so only from a trusted server environment. The snippets below are somewhat simplified and do not deal with error handling, security, deleting subcollections, or maximizing performance.

To learn more about one recommended approach to deleting collections in production, see Deleting Collections and Subcollections. You can also use the Firebase CLI to delete documents and collections. Use the following command to delete data:. Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4. For details, see the Google Developers Site Policies.

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Get data with Cloud Firestore

Manage projects programmatically. Use the Admin SDK. Manage project access IAM. Firebase predefined roles. Prototype and test with Emulator Suite. Use an extension in your project. Realtime Database.

Usage and Performance. Cloud Firestore.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I have a static method that gets all the documents in a collection. I am having trouble creating an array of these documents to return.

How could I do that? Let us call the Array list 'allItems'. My approach was to add each item that is created inside the for loop to an the allItems array list, but this list is null when I return it and android studio is prompting me to make the array list final.

There's nothing wrong with making it final, and given that code, it's impossible for it to return null, but very possibly might be emptybecause it's actually returning before Firebase even attempts to make a remote database query. That's the problem with being asynchronous - you need to wait for the result before you can return it. From there, refactor the rest of the code to pass in the listener you've already written rather than actually expect an object to be returned from the method call.

Learn more. How to get all documents from a firestore collection and return them in an array list? Asked 1 year, 4 months ago. Active 1 year, 4 months ago. Viewed 3k times. Oamar Kanji Oamar Kanji 1 1 gold badge 9 9 silver badges 19 19 bronze badges.

Active Oldest Votes. From there, refactor the rest of the code to pass in the listener you've already written rather than actually expect an object to be returned from the method call API. I write it in Kotlin, so please adapt this in your code. Hello World Hello World 2 2 silver badges 13 13 bronze badges. Thank you, I am having trouble understanding this though.

How will this allow me to return an array list with the documents?By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information.

Tried most of the answers but none worked out. Is there any way to query data in this structure? The docs only available for normal array. Not available for array of custom object. With your current document structure, it's not possible to perform the query you want. Firestore does not allow queries for individual fields of objects in list fields.

What you would have to do is create an additional field in your document that is queryable. For example, you could create a list field with only the list of string languages that are part of the document.

With this, you could use an array-contains query to find the documents where a language is mentioned at least once. For the document shown in your screenshot, you would have a list field called "languages" with values ["Swift", "Kotlin"]. Actually it is possible to perform such a query when having a database structure like yours.

I have replicated your schema and here are document1document2and document3. Note that you cannot query using partial incomplete data. You are using only the lang property to query, which is not correct. You should use an object that contains both properties, lang and years. Seeing your screenshot, at first glance, the experience array is a list of HashMap objects.

firestore get all documents in collection android

But here comes the nicest part, that list can be simply mapped into a list of custom objects. Let's try to map each object from the array to an object of type Experience. The model contains only two properties:. I don't know how you named the class that represents a document, but I named it simply Job. To keep it simple, I have only used two properties:. Now, to perform a search for all documents that contain in the array an object with the lang set to Swiftplease follow the next steps.

First, create a new object of the Experience class:. The result in the logcat will be the name of document1 and document2 :.Unlike a SQL database, there are no tables or rows. Instead, you store data in documentswhich are organized into collections.

Each document contains a set of key-value pairs. Cloud Firestore is optimized for storing large collections of small documents. All documents must be stored in collections. Documents can contain subcollections and nested objects, both of which can include primitive fields like strings or complex objects like lists. Collections and documents are created implicitly in Cloud Firestore. Simply assign data to a document within a collection. If either the collection or document does not exist, Cloud Firestore creates it.

In Cloud Firestore, the unit of storage is the document. A document is a lightweight record that contains fields, which map to values. Each document is identified by a name.

A document representing a user alovelace might look like this:. Complex, nested objects in a document are called maps. For example, you could structure the user's name from the example above with a map, like this:. You may notice that documents look a lot like JSON. In fact, they basically are. There are some differences for example, documents support extra data types and are limited in size to 1 MBbut in general, you can treat documents as lightweight JSON records.

Documents live in collections, which are simply containers for documents. For example, you could have a users collection to contain your various users, each represented by a document:. Cloud Firestore is schemaless, so you have complete freedom over what fields you put in each document and what data types you store in those fields.

Documents within the same collection can all contain different fields or store different types of data in those fields. However, it's a good idea to use the same fields and data types across multiple documents, so that you can query the documents more easily. A collection contains documents and nothing else. It can't directly contain raw fields with values, and it can't contain other collections. See Hierarchical Data for an explanation of how to structure more complex data in Cloud Firestore.

The names of documents within a collection are unique. You can provide your own keys, such as user IDs, or you can let Cloud Firestore create random IDs for you automatically. You do not need to "create" or "delete" collections.

After you create the first document in a collection, the collection exists. If you delete all of the documents in a collection, it no longer exists. Every document in Cloud Firestore is uniquely identified by its location within the database. The previous example showed a document alovelace within the collection users. To refer to this location in your code, you can create a reference to it. A reference is a lightweight object that just points to a location in your database.

You can create a reference whether or not data exists there, and creating a reference does not perform any network operations. For example, to create a reference to the alovelace document:. To understand how hierarchical data structures work in Cloud Firestore, consider an example chat app with messages and chat rooms.There are two ways to retrieve data stored in Cloud Firestore.

Either of these methods can be used with documents, collections of documents, or the results of queries:. When you set a listener, Cloud Firestore sends your listener an initial snapshot of the data, and then another snapshot each time the document changes. The following example shows how to retrieve the contents of a single document using get :.

For platforms with offline support, you can set the source option to control how a get call uses the offline cache. By default, a get call will attempt to fetch the latest document snapshot from your database.

On platforms with offline support, the client library will use the offline cache if the network is unavailable or if the request times out. You can specify the source option in a get call to change the default behavior. You can fetch from only the database and ignore the offline cache, or you can fetch from only the offline cache.

For example:. The previous example retrieved the contents of the document as a map, but in some languages it's often more convenient to use a custom object type. In Add Datayou defined a City class that you used to define each city. You can turn your document back into a City object:. To use custom objects, you must define a FirestoreDataConverter function for your class. To support automatic type serialization in Swift, your type must conform to the Codable protocol.

Important: Each custom class must have a public constructor that takes no arguments. In addition, the class must include a public getter for each property. Each custom class must have a public constructor that takes no arguments. You can also retrieve multiple documents with one request by querying documents in a collection. For example, you can use where to query for all of the documents that meet a certain condition, then use get to retrieve the results:.

By default, Cloud Firestore retrieves all documents that satisfy the query in ascending order by document ID, but you can order and limit the data returned.Unlike a SQL database, there are no tables or rows. Instead, you store data in documentswhich are organized into collections.

Getting data

Each document contains a set of key-value pairs. Cloud Firestore is optimized for storing large collections of small documents. All documents must be stored in collections. Documents can contain subcollections and nested objects, both of which can include primitive fields like strings or complex objects like lists.

Collections and documents are created implicitly in Cloud Firestore. Simply assign data to a document within a collection. If either the collection or document does not exist, Cloud Firestore creates it. In Cloud Firestore, the unit of storage is the document. A document is a lightweight record that contains fields, which map to values.

Each document is identified by a name. A document representing a user alovelace might look like this:. Complex, nested objects in a document are called maps. For example, you could structure the user's name from the example above with a map, like this:. You may notice that documents look a lot like JSON. In fact, they basically are.

There are some differences for example, documents support extra data types and are limited in size to 1 MBbut in general, you can treat documents as lightweight JSON records. Documents live in collections, which are simply containers for documents.

For example, you could have a users collection to contain your various users, each represented by a document:. Cloud Firestore is schemaless, so you have complete freedom over what fields you put in each document and what data types you store in those fields. Documents within the same collection can all contain different fields or store different types of data in those fields. However, it's a good idea to use the same fields and data types across multiple documents, so that you can query the documents more easily.

A collection contains documents and nothing else.Cloud Firestore provides powerful query functionality for specifying which documents you want to retrieve from a collection or collection group. After creating a query object, use the get function to retrieve the results:.

See Get Data for more information on retrieving query results. You can also add a listener to a query to get the current results and listen for future updates.

The where method takes three parameters: a field to filter on, a comparison operation, and a value. For iOS, Android, and Java, the comparison operator is explicitly named in the method. You can use the array-contains operator to filter based on array values. For example:. If the array has multiple instances of the value you query on, the document is included in the results only once. An in query returns documents where the given field matches any of the comparison values.

This query returns every city document where the country field is set to USA or Japan. Similarly, use the array-contains-any operator to combine up to 10 array-contains clauses on the same field with a logical OR.

An array-contains-any query returns documents where the given field is an array that contains one or more of the comparison values:. Results from array-contains-any are de-duped. Even if a document's array field matches more than one of the comparison values, the result set includes that document only once. Note the following limitations for in and array-contains-any :.

You can also chain multiple where methods to create more specific queries logical AND. A collection group consists of all collections with the same ID.

By default, queries retrieve results from a single collection in your database.

firestore get all documents in collection android

Use a collection group query to retrieve documents from a collection group instead of from a single collection. For example, you can create a landmarks collection group by adding a landmarks subcollection to each city:. We can use the simple and compound query described earlier to query a single city's landmarks subcollection, but you might also want to retrieve results from every city's landmarks subcollection at once.

(Ep 23) How To Structure & Retrieve Cloud Firestore Data With User’s Unique Id (UID)

The landmarks collection group consists of all collections with the ID landmarksand you can query it using a collection group query. For example, this collection group query retrieves all museum landmarks across all cities:. Before using a collection group query, you must create an index that supports your collection group query.

You can create an index through an error message, the console, or the Firebase CLI. For the web and mobile SDKs, you must also create rules that allow your collection group queries. Cloud Firestore either does not support or provides limited support for the following types of queries:.

firestore get all documents in collection android

Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4. For details, see the Google Developers Site Policies. Guides Get started with Firebase. Add Firebase to an app. Add Firebase to a game.

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