database does not exist

This error occurs when you try to connect to a database that doesn't exist in the PostgreSQL server.

The database does not exist error means the specified database wasn't found.

Understanding the Error

FATAL: database "myapp" does not exist

You're trying to connect to a database that hasn't been created.

Common Causes

1. Database Not Created

BASH

# Trying to connect to a database that doesn't exist
psql -d myapp  # Error if 'myapp' not created

2. Typo in Database Name

BASH

# Wrong name
psql -d myaap  # Typo: 'myaap' instead of 'myapp'

3. Wrong Environment

Connecting to production when database only exists in development, or vice versa.

4. Case Sensitivity

BASH

# Database names are case-sensitive if quoted
psql -d MyApp  # Different from 'myapp'

How to Fix It

Solution 1: Create the Database

SQL

-- Connect to postgres database first
psql -d postgres

-- Create your database
CREATE DATABASE myapp;

-- Or with owner
CREATE DATABASE myapp OWNER myuser;

Solution 2: List Available Databases

SQL

-- In psql
\l

-- Or with SQL
SELECT datname FROM pg_database WHERE datistemplate = false;

Solution 3: Create with Template

SQL

-- Create from template
CREATE DATABASE myapp_test TEMPLATE myapp;

-- Create with specific encoding
CREATE DATABASE myapp
  ENCODING 'UTF8'
  LC_COLLATE 'en_US.UTF-8'
  LC_CTYPE 'en_US.UTF-8';

Solution 4: Check Connection String

JAVASCRIPT

// Verify database name in connection string
const connectionString = 'postgresql://user:password@localhost:5432/myapp';
//                                                                    ^^^^^
// Make sure this matches your database name

Solution 5: Use createdb Command

BASH

# Create database from command line
createdb myapp

# With options
createdb -O myuser -E UTF8 myapp

Solution 6: Connect to Default Database First

BASH

# Connect to postgres database
psql -d postgres -U myuser

# Then create your database
CREATE DATABASE myapp;

# Reconnect
\c myapp

Database Naming Best Practices

SQL

-- Use lowercase and underscores
CREATE DATABASE my_app_production;  -- Good
CREATE DATABASE MyAppProduction;    -- Works but case-sensitive

-- Avoid spaces and special characters
CREATE DATABASE "My App";  -- Requires quotes everywhere
CREATE DATABASE my_app;    -- Better

Best Practices

Use consistent naming across environments
Script database creation for reproducibility
Use lowercase names without special characters
Check environment before running commands
Include database setup in deployment scripts