How to fix FATAL: database "dbname" does not exist in PostgreSQL

PostgreSQLBEGINNERHIGH

This error occurs when you attempt to connect to a PostgreSQL database that doesn't exist on the server. It commonly happens when psql tries to connect to a database with the same name as your OS user account, or when you specify an incorrect database name in your connection string.

What this error means

The "FATAL: database 'dbname' does not exist" error indicates that PostgreSQL received a valid connection request with valid credentials, but the target database is not present on the server. This is different from authentication failures. PostgreSQL has a unique behavior: when you run `psql` without specifying a database name with the `-d` flag, it attempts to connect to a database with the same name as the current operating system user. If this database hasn't been created, you'll get this error. For example: - If your OS user is `john` and you run `psql` without arguments, PostgreSQL tries to connect to a database named `john` - If you specify a database with `-d myapp` but the database doesn't exist, you get this error - This differs from MySQL/MariaDB which uses a different security model The SQLSTATE error code is 3D000 (database_name_not_found).

How to fix "FATAL: database "dbname" does not exist"

1Verify the database exists on the server

Connect to PostgreSQL using the default postgres database and list all databases:

bash

# Connect to the postgres database (default, always exists)
psql -h localhost -U postgres -d postgres

At the postgres=# prompt, list all databases:

sql

\l
-- or
SELECT datname FROM pg_database WHERE datistemplate = false;

This shows all non-template databases on your server. Check if your target database is listed.

To exit psql:

sql

\q

2Create the missing database

If the database doesn't exist, create it using the createdb command or SQL:

Method 1: Using createdb (recommended for scripts)

bash

# Basic creation
createdb -h localhost -U postgres myapp_db

# With additional options (specific owner, encoding)
createdb -h localhost -U postgres -O myapp_user -E UTF8 myapp_db

Method 2: Using CREATE DATABASE SQL

Connect to the postgres database and run:

bash

psql -h localhost -U postgres -d postgres

Then at the prompt:

sql

CREATE DATABASE myapp_db;

-- Or with specific owner and encoding
CREATE DATABASE myapp_db
  OWNER myapp_user
  ENCODING 'UTF8'
  LOCALE 'en_US.UTF-8';

-- Verify it was created
\l

Important parameters:
- OWNER: Which PostgreSQL role (user) owns the database. Defaults to the connecting user
- ENCODING: Character set. Use 'UTF8' for modern applications
- LOCALE / LC_COLLATE / LC_CTYPE: Language and collation settings (important for sorting and string operations)

Note: CREATE DATABASE cannot be run inside a transaction block. If you get an error about being in a transaction, first run ROLLBACK;

3Fix connection strings and environment variables

Ensure your application is connecting to the correct database name:

Check your connection string format:

PostgreSQL connection string patterns:

bash

# URL format (libpq)
postgresql://user:password@localhost:5432/database_name

# Connection parameters (key=value)
host=localhost dbname=database_name user=postgres password=yourpassword

Common mistakes to avoid:

1. Wrong database name:

javascript

// ✗ WRONG - database 'app' doesn't exist
   const pool = new Pool({ database: 'app' });

   // ✓ CORRECT - use the actual database name
   const pool = new Pool({ database: 'myapp_db' });

2. Using OS username instead of database name:

bash

# ✗ WRONG - assumes database named 'john' exists
   psql

   # ✓ CORRECT - explicitly specify database
   psql -d myapp_db

3. Missing database name in connection URL:

bash

# ✗ WRONG - no database specified
   psql postgresql://postgres@localhost

   # ✓ CORRECT - includes database name
   psql postgresql://postgres@localhost/myapp_db

Check environment variables:

bash

# See what your app is trying to use
echo $DATABASE_URL
echo $PGDATABASE
echo $PGHOST
echo $PGUSER

4For development: Create a user-specific database

If you're using the default behavior of psql (connecting to a database matching your OS username), create that database:

bash

# If your OS user is 'john', create a database named 'john'
sudo -u postgres createdb john

# Or manually as the postgres user
sudo -u postgres psql -c "CREATE DATABASE john;"

Now psql will work without arguments:

bash

psql  # Connects to database 'john'

For multi-user development environments:

Instead of creating per-user databases, create a shared development database and use it explicitly:

bash

# Create a shared development database
sudo -u postgres createdb dev_database

# Users connect explicitly
psql -d dev_database

5Verify connection parameters and credentials

Double-check all connection parameters:

bash

# Test connection with explicit parameters
psql \
  --host localhost \
  --port 5432 \
  --username postgres \
  --dbname myapp_db \
  --command "SELECT version();"

If this works, your database exists and is accessible. If not:

Check which PostgreSQL instance is running:

bash

# Find running PostgreSQL processes
ps aux | grep postgres

# Find the data directory (important for multi-instance setups)
# On Linux
grep data_directory /etc/postgresql/*/main/postgresql.conf

# On macOS with Homebrew
/usr/local/var/postgres/

Verify the server is listening on the expected port and host:

bash

# Check what ports PostgreSQL is listening on
ss -tlnp | grep postgres
# or
netstat -tlnp | grep postgres

# Test connectivity to the host/port
nc -zv localhost 5432
telnet localhost 5432

6For Docker: Ensure database is created during initialization

When using PostgreSQL in Docker, the database must be created. The official postgres image has initialization scripts:

Using POSTGRES_DB environment variable:

dockerfile

FROM postgres:16

ENV POSTGRES_USER=postgres
ENV POSTGRES_PASSWORD=secret
ENV POSTGRES_DB=myapp_db  # This database will be created automatically

Or with docker-compose:

yaml

services:
  postgres:
    image: postgres:16
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: secret
      POSTGRES_DB: myapp_db  # Created automatically
    volumes:
      - postgres_data:/var/lib/postgresql/data
    ports:
      - "5432:5432"

volumes:
  postgres_data:

For custom initialization scripts:

Place SQL or shell scripts in /docker-entrypoint-initdb.d/ and they'll run once when the container starts:

dockerfile

FROM postgres:16

COPY init-schema.sql /docker-entrypoint-initdb.d/

Important: Initialization scripts only run when the volume is empty. If you want to reinitialize:

bash

# Remove the volume
docker volume rm myapp_postgres_data

# Recreate the container
docker-compose up -d postgres

How to fix FATAL: database "dbname" does not exist in PostgreSQL

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