- 01
Why are Django QuerySets described as lazy?
Building or refining a QuerySet does not normally execute SQL until its results are evaluated. This allows filters to compose efficiently, but repeated evaluation or hidden relationship access can still create extra queries.
- 02
How do select_related and prefetch_related differ?
Question codepythonbooks = Book.objects.all() for book in books: print(book.author.name)select_related uses SQL joins for single-valued relationships, while prefetch_related performs additional queries and joins results in Python for multi-valued relationships. The correct choice depends on relationship shape and data volume.
Answer codepythonbooks = Book.objects.select_related('author').prefetch_related('tags') for book in books: print(book.author.name, list(book.tags.all())) - 03
What security protections does Django provide by default?
Django includes tools for CSRF protection, escaped templates, secure password hashing, host validation, and safe ORM parameterization. These protections still depend on correct configuration and can be bypassed by unsafe code.
- 04
When should database transactions be used?
Use a transaction when a set of database changes must succeed or fail as one unit. Keep transactions focused because long transactions increase contention and should not normally wrap slow external calls.
- 05
What belongs in Django middleware?
Middleware is suited to request-wide concerns such as authentication integration, correlation IDs, security headers, or locale. Model and use-case behavior should remain in clearer domain or application layers.
- 06
How would you test a Django application?
Test domain behavior directly, then cover views or APIs with realistic requests, permissions, validation, and database effects. Use factories and targeted integration tests while keeping external services controlled.
Backend Frameworks
Django Interview Questions and Answers
Review Django interview questions covering models, querysets, middleware, forms, security, transactions, APIs, and testing.
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