How to fix Invalid catalog name in PostgreSQL

Connect to PostgreSQL as a superuser and list all databases:

psql -U postgres

Then in the PostgreSQL prompt:

\l

This shows all databases. Look for the database name you're trying to connect to. If it doesn't appear in the list, you need to create it.

Verify the database name in your connection string matches exactly (case-sensitive). Common connection string formats:

postgresql://user:password@localhost:5432/dbname

Ensure:
- The database name is spelled correctly
- No extra spaces or special characters
- The database exists (from step 1)

Check in:
- Environment variables (.env, .env.local)
- Configuration files (config.js, database.yml, etc.)
- Application code with hardcoded connections

If the database is missing, create it:

CREATE DATABASE mydbname;

For specific character encoding:

CREATE DATABASE mydbname
  ENCODING 'UTF8'
  LC_COLLATE 'C'
  LC_CTYPE 'C'
  TEMPLATE template0;

Then reconnect with the correct connection string.

Some tools (Ecto, Rails, etc.) use a "maintenance database" to create/drop other databases. By default it's "postgres", but some cloud providers use different names:

# Ecto example
config :myapp, MyApp.Repo, maintenance_database: "defaultdb"

# Rails example
adapter: postgresql
database: <%= ENV["DB_NAME"] %>
maintenance_db: defaultdb

Check your database hosting provider's documentation for the correct maintenance database name.