Cloud Firestore in iOS Swift - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Cloud Firestore in mobile development?

Cloud Firestore is a flexible, scalable database for mobile, web, and server development. It stores data in documents, which are organized into collections, and syncs data in real-time across devices.

beginner

How do you add a document to a Firestore collection in Swift?

Use the Firestore instance to reference a collection, then call addDocument(data:) with a dictionary of key-value pairs representing your data.

beginner

What is the difference between a document and a collection in Firestore?

A document is a single record that contains fields with data. A collection is a group of documents. Collections can contain documents, and documents can contain subcollections.

intermediate

How does Firestore handle real-time updates?

Firestore lets your app listen to document or collection changes. When data changes, Firestore sends updates instantly to keep your UI in sync without manual refresh.

intermediate

What is a Firestore query and how is it used?

A Firestore query lets you retrieve documents that match specific conditions, like filtering by a field value or ordering results. Queries help you get only the data you need.

Which Firestore data structure holds multiple documents?

A Database

B Document

C Field

D Collection

A collection is a container for multiple documents in Firestore.

How do you listen for real-time updates in Firestore on iOS?

A Call getDocuments() repeatedly

B Use a timer to refresh data

C Use addSnapshotListener() on a document or collection reference

D Use URLSession to fetch data

addSnapshotListener() sets up a real-time listener that triggers when data changes.

What type of data does a Firestore document store?

A Key-value pairs

B Only strings

C Only numbers

D Only arrays

Documents store data as key-value pairs, where values can be various types.

Which method adds a new document with an auto-generated ID in Firestore?

A addDocument(data:)

B setData(_:)

C updateData(_:)

D delete()

addDocument(data:) creates a new document with a unique ID automatically.

How can you filter documents in Firestore?

A By using setData(_:)

B By using whereField() in a query

C By calling delete()

D By using addSnapshotListener()

whereField() lets you specify conditions to filter documents in queries.

Explain how you would set up a Firestore listener in Swift to update your app UI in real-time.

Think about how Firestore notifies your app when data changes.

Describe the structure of data in Cloud Firestore and how documents and collections relate.

Imagine folders and files on your computer.