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     Antipatterns

    1. A GET request with side-effects
    2. A model with a …Model suffix
    3. Chaining querysets together
    4. Checking ownership through the UserPassesTestMixin
    5. Checking request method with if request.POST
    6. Constructing a new form when validation fails
    7. Fetching the logged in user with a query
    8. Filtering in the template
    9. Foreign key with _id suffix
    10. Giving related_name=… the same name as the relation
    11. Manually constructing a slug
    12. Modifying slugs and primary keys of model objects
    13. (Over)use of .values()
    14. Passing parameters directly in the query string of a URL
    15. Plural model class names
    16. Refer to the User model directly
    17. Rendering content after a successful POST request
    18. Rendering into JavaScript
    19. Return a JsonResponse with safe=False
    20. Signals
    21. Use datetime.now as default=… for a created_on field
    22. Use .get(…) to retrieve the object in a view
    23. Using a FloatField for currencies
    24. Using commit=False when altering the instance in a ModelForm
    25. Using len(…) on a QuerySet with no further use
    26. Using multiple forms on the same page without prefixing
    27. Using request.POST or None

     Patterns

    1. Annotate a condition as BooleanField
    2. Date(Time)Fields that store a week or month
    3. Match multiple strings in a case-insensitive manner
    4. Set values to a created/updated object in a class-based view

     Troubleshooting

    1. A certain field does not appear in the migrations and in the database table
    2. Can not extract/filter a Date(Time)Field when time zones are enabled