Install PostgreSQL on Debian 12

Step 1 – Install

apt update && apt upgrade -y
apt install -y postgresql postgresql-contrib
systemctl enable --now postgresql

Step 2 – Connect as superuser

sudo -u postgres psql

Step 3 – Create database and user

CREATE USER appuser WITH PASSWORD 'StrongPass123!';
CREATE DATABASE appdb OWNER appuser;
GRANT ALL PRIVILEGES ON DATABASE appdb TO appuser;
\q

Key files

Allow remote connections (optional)

/etc/postgresql/15/main/postgresql.conf: listen_addresses = '*'

/etc/postgresql/15/main/pg_hba.conf: host appdb appuser 0.0.0.0/0 scram-sha-256

systemctl reload postgresql 2>/dev/null || rc-service postgresql-14 reload 2>/dev/null || rcctl reload postgresql