Creating collections and documents in Firebase - Step-by-Step CLI Walkthrough

Introduction

When you want to store data in Firebase Firestore, you organize it into collections and documents. Collections hold documents, and documents hold your actual data. This helps keep your data neat and easy to find.

When you want to save user profiles in your app.

When you need to store messages in a chat application.

When you want to keep track of orders in an online store.

When you want to save settings or preferences for each user.

When you want to add new data entries without changing existing ones.

Commands

This command creates a document with ID 'user123' inside the 'users' collection and adds the fields 'name' and 'age' with their values.

Terminal

firebase firestore:documents:create users/user123 --data '{"name":"Alice","age":30}'

Expected Output

Document users/user123 created successfully.

→

--data - Specifies the JSON data to store in the document.

This command retrieves and shows the data stored in the document 'user123' inside the 'users' collection to verify it was created correctly.

Terminal

firebase firestore:documents:get users/user123

Expected Output

{

  "name": "Alice",

  "age": 30

}

Creates another document 'user124' in the 'users' collection with different data to show how to add multiple documents.

Terminal

firebase firestore:documents:create users/user124 --data '{"name":"Bob","age":25}'

Expected Output

Document users/user124 created successfully.

→

--data - Specifies the JSON data to store in the document.

Lists all collections in your Firestore database to confirm the 'users' collection exists.

Terminal

firebase firestore:collections:list

Expected Output

users

Key Concept

If you remember nothing else from this pattern, remember: collections hold documents, and documents hold your data as key-value pairs.

Common Mistakes

Trying to create a document without specifying data.

Firestore requires data to create a document; otherwise, the command fails.

Always include the --data flag with valid JSON when creating a document.

Using incorrect document paths like missing collection name.

Firestore needs the full path including collection and document ID to locate or create documents.

Always specify the collection name followed by the document ID, like 'users/user123'.

Summary

Use 'firebase firestore:documents:create' with --data to add documents to collections.

Verify document creation with 'firebase firestore:documents:get'.

List collections using 'firebase firestore:collections:list' to see your data groups.