PostgreSQL with Django

Django ships first-class PostgreSQL support—JSONField, ArrayField, indexes, and migrations emitting Postgres DDL.

settings.py DATABASES

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': 'myapp',
        'USER': 'myapp_user',
        'PASSWORD': os.environ['DB_PASSWORD'],
        'HOST': '127.0.0.1',
        'PORT': '5432',
        'CONN_MAX_AGE': 60,
    }
}

Postgres-specific fields

from django.contrib.postgres.fields import ArrayField
from django.db import models

class Article(models.Model):
    tags = ArrayField(models.CharField(max_length=40), default=list)
    meta = models.JSONField(default=dict)

Requires PostgreSQL backend—SQLite dev DB cannot run these migrations unchanged.

Migrations and raw SQL

Use RunSQL for partial indexes and extensions. Keep dev/prod engines aligned to avoid surprise migration failures.

Important interview questions and answers

1. Q: Why not SQLite in production Django?
   A: Concurrency and Postgres-specific fields—SQLite fine for local learning only.
2. Q: django.contrib.postgres?
   A: Optional contrib package with Postgres field types and lookups.

Self-check

1. Which ENGINE string selects PostgreSQL?
2. What field type maps to JSONB?

Pitfall: SQLite dev + Postgres-only fields break migrations at deploy—align engines early.