Creating tables via dashboard in Supabase - Try It Yourself

Creating tables via dashboard

📖 Scenario: You are building a blog application with Supabase. You need to create the database schema with a users table and a posts table with a foreign key relationship. You'll write the SQL that the dashboard generates behind the scenes.

🎯 Goal: Create two related tables with proper primary keys, constraints, foreign keys, and Row Level Security enabled.

📋 What You'll Learn

Create a users table with UUID primary key and email

Create a posts table with foreign key to users

Enable Row Level Security on both tables

Add a basic RLS policy for authenticated read access

💡 Why This Matters

🌍 Real World

Every Supabase application needs tables with proper RLS policies. The dashboard provides a visual way to create them, but understanding the generated SQL is essential for migrations and debugging.

💼 Career

Full-stack developers using Supabase must understand table creation, foreign keys, and RLS to build secure applications.

1

Create the users table

Create a table public.users with columns: id as UUID with default gen_random_uuid() as PRIMARY KEY, email as TEXT NOT NULL UNIQUE, and created_at as TIMESTAMPTZ with default now().

Supabase

-- Create the users table
-- Your code here

Need a hint?

Use gen_random_uuid() as the default value for UUID primary keys in Supabase.

2

Create the posts table with foreign key

Create a table public.posts with columns: id as BIGINT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY, user_id as UUID referencing public.users(id) with ON DELETE CASCADE, title as TEXT NOT NULL, and created_at as TIMESTAMPTZ with default now().

Supabase

CREATE TABLE public.users (
  id UUID DEFAULT gen_random_uuid() PRIMARY KEY,
  email TEXT NOT NULL UNIQUE,
  created_at TIMESTAMPTZ DEFAULT now()
);

-- Create the posts table with foreign key to users
-- Your code here

Need a hint?

Use REFERENCES public.users(id) ON DELETE CASCADE to create the foreign key with cascade delete.

3

Enable Row Level Security

Enable Row Level Security on both public.users and public.posts tables using ALTER TABLE ... ENABLE ROW LEVEL SECURITY.

Supabase

CREATE TABLE public.users (
  id UUID DEFAULT gen_random_uuid() PRIMARY KEY,
  email TEXT NOT NULL UNIQUE,
  created_at TIMESTAMPTZ DEFAULT now()
);

CREATE TABLE public.posts (
  id BIGINT GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
  user_id UUID REFERENCES public.users(id) ON DELETE CASCADE,
  title TEXT NOT NULL,
  created_at TIMESTAMPTZ DEFAULT now()
);

-- Enable RLS on both tables
-- Your code here

Need a hint?

Use ALTER TABLE table_name ENABLE ROW LEVEL SECURITY for each table.

4

Add a read policy for authenticated users

Create a policy named "Users can read all posts" on public.posts for SELECT using the role authenticated with the check (true) to allow all authenticated users to read posts.

Supabase

ALTER TABLE public.users ENABLE ROW LEVEL SECURITY;
ALTER TABLE public.posts ENABLE ROW LEVEL SECURITY;

-- Create a SELECT policy for authenticated users
-- Your code here

Need a hint?

Use CREATE POLICY name ON table FOR SELECT TO role USING (expression).