How to write stored procedures in Supabase?

 

Step 1: Understanding Supabase and Stored Procedures

 

Before you begin writing stored procedures in Supabase, it's important to understand what Supabase is and what stored procedures do. Supabase is an open-source alternative to Firebase, providing a suite of tools for developing applications. In Supabase, stored procedures are written using SQL and are used to include logic that can be reused by various database requests.

 

Step 2: Set Up Your Supabase Project

 

Make sure you have a Supabase project set up. If you haven't already, you can set one up by creating an account on the Supabase website and starting a new project. After that, you will be provided with the credentials and a URL to use with your client.

 

Step 3: Accessing the SQL Editor

 

Go to your Supabase project dashboard and click on the "Database" option on the left-hand menu. Here you will find the SQL editor, which allows you to run SQL commands directly against your database. This is where you will write your stored procedures.

 

Step 4: Writing Your First Stored Procedure

 

To write a stored procedure, you must use the CREATE FUNCTION SQL command. Let's write a simple stored procedure to fetch data from a table called users.

<pre><code class="hljs">
CREATE FUNCTION get_all_users()
RETURNS TABLE(id INT, name TEXT, email TEXT) AS $$
BEGIN
    RETURN QUERY
    SELECT id, name, email FROM users;
END;
$$ LANGUAGE plpgsql;
</code></pre>

Here’s the breakdown of the stored procedure:

• CREATE FUNCTION: This command creates a stored procedure named get_all_users.
• RETURNS TABLE: Defines the types of data that the procedure returns. In this case, it's a table with id, name, and email.
• LANGUAGE plpgsql: The procedure uses the PostgreSQL procedural language (PL/pgSQL).

 

Step 5: Running Your Stored Procedure

 

To run the stored procedure you created, you can call it like a regular SQL function:

<pre><code class="hljs">
SELECT * FROM get_all_users();
</code></pre>

Run this command in the SQL editor to execute the stored procedure and retrieve all users from the users table.

 

Step 6: Modifying a Stored Procedure

 

Suppose you need to modify the stored procedure to include a parameter for filtering users by a specific condition. Here’s how you could update the procedure:

<pre><code class="hljs">
CREATE OR REPLACE FUNCTION get_users_by_status(status TEXT)
RETURNS TABLE(id INT, name TEXT, email TEXT) AS $$
BEGIN
    RETURN QUERY
    SELECT id, name, email FROM users WHERE user_status = status;
END;
$$ LANGUAGE plpgsql;
</code></pre>

• CREATE OR REPLACE FUNCTION: This command modifies an existing procedure or creates it if it doesn't exist.
• Parameter status TEXT: This allows the function to accept a status parameter for filtering results.

 

Step 7: Testing Your Modified Stored Procedure

 

Test the modified stored procedure by running:

<pre><code class="hljs">
SELECT * FROM get_users_by_status('active');
</code></pre>

This will return all users where the user_status matches 'active'.

 

Step 8: Additional Enhancements

 

You can further enhance your stored procedures to handle more complex logic or integrate with other functions available in Supabase. Ensure your procedures are optimized for performance and security by consulting PostgreSQL documentation and best practices.

 

Step 9: Saving and Managing Stored Procedures

 

All stored procedures you create will be saved in your database system. You can view and manage them through the Supabase dashboard or using SQL commands within the SQL editor.

 

This step-by-step guide should help you get started with writing stored procedures in Supabase, enabling you to manage database logic effectively within your applications.