How do you create a read-only user in PostgreSQL?

How to Create a Read-Only User in PostgreSQL 👀🔒

Have you ever wanted to create a PostgreSQL user that can only perform SELECT queries on a specific database? You're not alone! In this guide, we'll walk you through the process of creating a read-only user in PostgreSQL, highlighting common issues and providing easy solutions. So, let's dive in and empower you with the knowledge! 💪

The MySQL Equivalent Command 📜

Before we jump into PostgreSQL, let's quickly address the MySQL equivalent command mentioned in the question:

GRANT SELECT ON mydb.* TO 'xxx'@'%' IDENTIFIED BY 'yyy';

In MySQL, this command grants the user 'xxx' the ability to execute SELECT queries on the 'mydb' database, connecting from any host ('%') with the password 'yyy'. So, how do we achieve the same result in PostgreSQL? Let's find out! 🕵️‍♀️

Granting SELECT Permissions in PostgreSQL 🛠️

The PostgreSQL syntax differs slightly from MySQL when it comes to granting permissions. In PostgreSQL, we grant permissions at the table level, rather than the database level. But worry not, we have a workaround for this particular challenge! 🤝

To create a read-only user in PostgreSQL, follow these simple steps:

1. Create a login role: Start by creating a login role for the user using the CREATE ROLE command. For example:

   CREATE ROLE xxx LOGIN PASSWORD 'yyy';

   In this command, we create a login role named 'xxx' with the password 'yyy'. Feel free to customize the role name and password as per your preference.

2. Grant USAGE permissions: Grant the user USAGE permissions on the target database. For instance, to grant USAGE permissions on the 'mydb' database:

   GRANT USAGE ON DATABASE mydb TO xxx;

   This step ensures that the user can connect to the specified database.

3. Grant SELECT permissions on tables: Now, let's grant SELECT permissions on all existing tables in the 'mydb' database. Execute the following command to accomplish this:

   GRANT SELECT ON ALL TABLES IN SCHEMA public TO xxx;

   The above command grants SELECT permissions on tables in the 'public' schema. If your tables reside in a different schema, modify the command accordingly.

And that's it! ✨ You have successfully created a read-only user in PostgreSQL. The user 'xxx' can now connect to the 'mydb' database and execute SELECT queries on all tables in the 'public' schema.

A Word of Caution ⚠️

Keep in mind that the above steps will grant the user read-only access to all existing tables in the specified schema. However, if new tables are added in the future, the user won't have automatically granted permissions on them. To handle this, you can either manually grant SELECT permissions on new tables or explore advanced options like using custom functions, triggers, or event triggers.

Conclusion & Call-to-Action 🏁

Congratulations! You have successfully created a read-only user in PostgreSQL, allowing them to perform SELECT queries on a specific database. We hope this guide has helped you navigate through the process smoothly and address any common issues you may have encountered.

Now it's your turn! Give it a try and let us know your experiences in the comments below. Have any questions or additional tips? We'd love to hear them too! Join the conversation and share your thoughts. 👇