Setting up a Supabase project - Practice Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Supabase Project Initialization

When you create a new Supabase project, what is the first essential step to connect your application to the Supabase backend?

A Obtain the API URL and anon public key from the Supabase dashboard to configure your client.

B Install a local database server on your machine before creating the project.

C Write SQL queries manually before creating the project to define tables.

D Set up a virtual machine to host the Supabase backend.

💡 Hint

Think about what you need to connect your app to the cloud service after project creation.

After creating a Supabase project, you get an API URL and anon key. These let your app talk to the Supabase backend securely.

❓ Configuration

intermediate

Supabase Environment Variable Setup

You want to securely store your Supabase project URL and anon key in a Node.js app. Which environment variable setup is correct?

Supabase

import { createClient } from '@supabase/supabase-js';

const supabaseUrl = process.env.SUPABASE_URL;
const supabaseKey = process.env.SUPABASE_ANON_KEY;
const supabase = createClient(supabaseUrl, supabaseKey);

A Use a global variable in the browser to store the URL and key.

B Hardcode the URL and key directly in the code for faster access.

C Store the URL and key in a JSON file and import it directly.

D Set SUPABASE_URL and SUPABASE_ANON_KEY in a .env file and load them with dotenv package.

💡 Hint

Think about keeping secrets safe and not exposing keys in code.

Using environment variables with a .env file and dotenv keeps secrets out of code and allows easy configuration.

❓ Architecture

advanced

Choosing Supabase Database Schema Design

You are designing a Supabase project for a simple blog. Which schema design best supports posts with multiple tags and user comments?

A Create tables: posts, tags, post_tags (join table), users, comments with foreign keys linking appropriately.

B Create one big table combining posts, tags, users, and comments in columns.

C Create tables: posts, tags, users only; store comments inside posts as JSON.

D Create tables: posts and comments only, store tags as comma-separated strings in posts.

💡 Hint

Think about how to represent many-to-many relationships and keep data organized.

Using separate tables with join tables and foreign keys is best practice for relational data like posts, tags, users, and comments.

❓ security

advanced

Supabase Row Level Security (RLS) Configuration

You want to restrict access so users can only read their own profile data in Supabase. Which RLS policy is correct?

Supabase

CREATE POLICY "Users can view their own profile" ON profiles
FOR SELECT USING (auth.uid() = user_id);

A CREATE POLICY "Users can view all profiles" ON profiles FOR SELECT USING (true);

B CREATE POLICY "Users can view their own profile" ON profiles FOR SELECT USING (auth.uid() = user_id);

C CREATE POLICY "Users can view profiles" ON profiles FOR SELECT USING (user_id = 'admin');

D No policy needed; all profiles are public by default.

💡 Hint

Think about matching the authenticated user ID to the profile's user ID.

This policy allows users to select only rows where the user_id matches their authenticated ID, enforcing privacy.

❓ service_behavior

expert

Supabase Realtime Behavior on Database Changes

In a Supabase project with Realtime enabled on the 'messages' table, what happens when a new message row is inserted?

A Clients receive an event only if they query the table again.

B Only the client that inserted the row receives an event notification.

C All clients subscribed to 'messages' receive an event with the new row data immediately.

D No event is sent until the database is manually refreshed.

💡 Hint

Think about how realtime subscriptions work to keep clients updated.

Supabase Realtime pushes changes instantly to all subscribed clients when data changes occur.