MySQL Error 1049 — Unknown Database

MySQL Error 1049: Unknown Database

Error 1049 occurs when you try to connect to or use a database that does not exist on the MySQL server.

Error Format

ERROR 1049 (42000): Unknown database 'myapp_production'

Common Causes

1. Database not created yet:

-- List existing databases
SHOW DATABASES;

-- Create the database
CREATE DATABASE myapp_production
  CHARACTER SET utf8mb4
  COLLATE utf8mb4_unicode_ci;

2. Typo in database name: MySQL database names are case-sensitive on Linux (because they map to filesystem directories), but case-insensitive on macOS and Windows.

# Check the lower_case_table_names setting
mysql -e "SHOW VARIABLES LIKE 'lower_case_table_names'"

3. Wrong environment configuration:

# .env file might reference the wrong database
DATABASE_URL=mysql://user:pass@localhost:3306/wrong_name

# Fix: use the correct database name
DATABASE_URL=mysql://user:pass@localhost:3306/correct_name

4. ORM migration not run:

# Rails
rails db:create

# Django
python manage.py migrate

# Prisma
npx prisma db push

# Sequelize
npx sequelize db:create

Docker-Specific Issues

When using Docker, the database is created inside the container. If you recreate the container without a persistent volume, the database is lost:

# docker-compose.yml - add a volume!
services:
  db:
    image: mysql:8
    environment:
      MYSQL_DATABASE: myapp
    volumes:
      - mysql_data:/var/lib/mysql

volumes:
  mysql_data:

Prevention

• Use environment-specific database names (myapp_dev, myapp_test, myapp_prod)
• Include database creation in your setup scripts
• Document the setup process in your project README
• Use Docker volumes for persistent data