How To Fix PostgreSQL Error: Database doesn’t exist

Overview

Encountering the ‘Database doesn’t exist’ error in PostgreSQL can be a stumbling block when developing a project. This error suggests that the application is trying to connect to a PostgreSQL database that does not exist within the PostgreSQL DBMS (Database Management System). In this guide, we will explore some common reasons for this error and a variety of solutions to resolve it.

Solution 1: Check Database Name

The error might be a result of an incorrect database name in the connection string or application configuration file.

• Step 1: Confirm the existing databases in PostgreSQL using the \l command in psql.
• Step 2: Verify the database name specified in your application’s configuration.
• Step 3: Correct any discrepancies in the database name.
• Step 4: Attempt to reconnect to the database.

This approach is simple and quick to verify but is a manual process.

Solution 2: Create Missing Database

If a database does indeed not exist, you can create it using the createdb command or SQL statement.

• Step 1: Connect to PostgreSQL using the psql client or other PostgreSQL interfaces.
• Step 2: Use the createdb command or SQL statement to create the database.
• Step 3: Configure your application to connect to the new database.

Example:

CREATE DATABASE your_database_name;

This approach equires database creation privileges.

Solution 3: Grant Proper Access

Sometimes, the user might lack permission to the database, even if it exists.

• Step 1: Verify the user’s permission to the database with the \l command.
• Step 2: Adjust permissions if necessary using the ALTER DATABASE or GRANT SQL commands.
• Step 3: Confirm the user now has access.

Example:

GRANT ALL PRIVILEGES ON DATABASE your_database_name TO your_user_name;

You must have superuser access to grant permissions.

Please note, in each case, replacing ‘your_database_name’ with the name of your actual target database and ‘your_user_name’ with the valid username for your PostgreSQL setup.

Conclusion

The methods mentioned provide a pathway to resolve the common ‘Database doesn’t exist’ error in PostgreSQL, but always remember to double-check and validate each approach within the context of your specific project requirements before implementing changes.