python

Window functions perform calculations across rows related to the current row. I use them for running totals, rankings, and moving averages. Django's Window expression with functions like RowNumber, Rank, DenseRank provide SQL window function support.

Extending Django's user model should be done early in projects. I use AbstractBaseUser for full control or AbstractUser to extend the default. Setting AUTH_USER_MODEL points Django to my custom model. I add fields like phone, avatar, or preferences. F

Custom error pages improve user experience and brand consistency. I create templates named 404.html, 500.html, 403.html, and 400.html in the templates root. Django serves these automatically when DEBUG=False. For custom logic, I can override error han

The Django admin is powerful when customized. I set list_display for column layout, list_filter and search_fields for finding records. Using readonly_fields, I prevent editing certain fields. The fieldsets organize the form layout. For computed values

Custom template filters transform variables in templates. I decorate functions with @register.filter and optionally set is_safe=True for HTML output. Filters take one or two arguments. For formatting dates, numbers, or text, filters keep logic out of

Custom middleware intercepts all requests and responses. I implement __init__ and __call__ methods. Middleware can modify requests before views, modify responses after views, or short-circuit entirely. Common uses include authentication, logging, CORS

Multi-tenancy allows multiple clients to share one application with isolated data. I use django-tenant-schemas for PostgreSQL schema-based isolation. Each tenant gets a separate schema (database namespace). The middleware routes requests to correct te

Q objects enable complex query logic with OR, AND, and NOT operations. I combine them with | for OR and & for AND. The ~Q() syntax negates a condition. This is cleaner than raw SQL for dynamic filters. I build Q objects conditionally based on user

Database transactions ensure data integrity when multiple operations must succeed or fail together. I use @transaction.atomic on views or functions to wrap them in a transaction. For partial rollbacks, I use transaction.atomic() as a context manager a

I create custom permission classes to encapsulate authorization logic outside of views. This IsOwnerOrReadOnly pattern is useful for resources where anyone can read but only the owner can modify. By implementing has_object_permission, I can make granu

Management commands are perfect for scripts that need Django's ORM and settings. I create them in management/commands/ and extend BaseCommand. The add_arguments method defines CLI options using argparse. I use self.stdout.write with style helpers for

Custom auth backends enable alternative authentication methods. I subclass ModelBackend and override authenticate(). Common use cases include email login, LDAP, OAuth, or custom token auth. The backend returns a user object or None. I add it to AUTHEN