Django Cheat Sheet

Updated 2026-07-29

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Django is a high-level Python web framework that follows the Model-Template-View (MTV) architectural pattern, enabling rapid development of secure and maintainable websites. Built with the philosophy of "batteries included," Django provides a comprehensive toolkit including an ORM for database interactions, a powerful template engine, robust authentication and authorization, and extensive middleware capabilities. Django 5.2 (current LTS) introduced composite primary keys and async-native ORM methods, and the framework's lazy QuerySet evaluation — where queries hit the database only when explicitly accessed — remains the key mental model for writing efficient code.

What This Cheat Sheet Covers

This topic spans 34 focused tables and 332 indexed concepts, 178 flashcards, 11 practice tests with 394 questions. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.

Table 1: Model FieldsTable 2: QuerySet MethodsTable 3: Field LookupsTable 4: Q Objects and Complex QueriesTable 5: F ExpressionsTable 6: Advanced Query ExpressionsTable 7: Model Meta OptionsTable 8: Model InheritanceTable 9: Model ValidatorsTable 10: Views — Function-BasedTable 11: Views — Class-BasedTable 12: Async SupportTable 13: URLs and RoutingTable 14: Templates — TagsTable 15: Templates — FiltersTable 16: Custom Template TagsTable 17: FormsTable 18: Authentication and AuthorizationTable 19: MiddlewareTable 20: Admin CustomizationTable 21: SignalsTable 22: MigrationsTable 23: Management CommandsTable 24: Sessions and MessagesTable 25: CachingTable 26: SecurityTable 27: Static and Media FilesTable 28: TestingTable 29: PaginationTable 30: EmailTable 31: Database TransactionsTable 32: Database FunctionsTable 33: Custom ManagersTable 34: Context Processors

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Table 1: Model Fields

Fields are the building blocks of every Django model, each one maps to a database column and decides what kind of data it holds, how it validates, and how it renders in a form. Reach here when you're sketching out a model and need to pick the right type, from simple text and numbers to the relationship fields (ForeignKey, ManyToManyField, OneToOneField) that wire your tables together. A few constraints are easy to forget, like CharField requiring max_length and ForeignKey requiring on_delete.

Field	Example	Description
CharField	`name = models.CharField(max_length=200)`	• Required `max_length` • stores short text strings • rendered as `<input type="text">` in forms.
TextField	`description = models.TextField()`	• Unlimited text storage • rendered as `<textarea>` in forms • no `max_length` validation.
IntegerField	`age = models.IntegerField()`	• Stores integers from -2147483648 to 2147483647 • use `BigIntegerField` for larger range.
FloatField	`price = models.FloatField()`	• Stores floating-point numbers as Python `float` • use `DecimalField` for financial precision.
DecimalField	`amount = models.DecimalField(max_digits=10, decimal_places=2)`	• Required `max_digits` and `decimal_places` • precise decimal storage for financial data • avoids float precision issues.
BooleanField	`is_active = models.BooleanField(default=True)`	• Stores True/False • rendered as checkbox • use `null=True` for three-state nullable boolean (NullBooleanField was removed in Django 4.0).
DateField	`signup_date = models.DateField(auto_now_add=True)`	• Stores a date • `auto_now` updates on every save, `auto_now_add` sets once on creation.
DateTimeField	`created_at = models.DateTimeField(auto_now_add=True)`	• Stores date and time with timezone awareness if `USE_TZ=True` • uses Python `datetime.datetime`.
EmailField	`email = models.EmailField(unique=True)`	• CharField with email validation • `max_length` defaults to 254 • uses `EmailValidator`.
URLField	`website = models.URLField()`	• CharField with URL validation • `max_length` defaults to 200 • validates using `URLValidator`.
JSONField	`data = models.JSONField(default=dict)`	• Stores JSON-encoded data • supports native database JSON types • queryable with key lookups.
SlugField	`slug = models.SlugField(unique=True)`	• CharField for URL slugs • allows letters, numbers, underscores, hyphens • typically paired with `prepopulated_fields` in admin.
UUIDField	`id = models.UUIDField(primary_key=True, default=uuid.uuid4)`	• Stores a universally unique identifier • useful for public-facing IDs instead of sequential integers.
ForeignKey	`author = models.ForeignKey(User, on_delete=models.CASCADE)`	• Many-to-one relationship • requires `on_delete` (CASCADE, PROTECT, SET_NULL, SET_DEFAULT, DO_NOTHING) • creates database index automatically.
ManyToManyField	`tags = models.ManyToManyField(Tag)`	• Many-to-many relationship • creates intermediary table automatically • use `through` for custom intermediary model.
OneToOneField	`profile = models.OneToOneField(User, on_delete=models.CASCADE)`	• One-to-one relationship • similar to ForeignKey with `unique=True` • useful for extending a model without inheritance.
FileField	`document = models.FileField(upload_to='docs/')`	• Handles file uploads • `upload_to` defines storage path relative to `MEDIA_ROOT`.
ImageField	`photo = models.ImageField(upload_to='photos/')`	• FileField with image validation • requires Pillow library • optionally stores width and height.
GeneratedField	`area = models.GeneratedField(` `expression=F('side') * F('side'),` `output_field=models.IntegerField(),` `db_persist=True)`	• Database-computed column (Django 5.0+) • always derived from other fields at database level • `db_persist=True` stores value; `False` computes on read.

Table 2: QuerySet Methods

The QuerySet API is where you spend most of your time talking to the database, fetching, filtering, creating, updating, and shaping rows without writing SQL. Keep the lazy evaluation rule in mind: methods like filter() and order_by() just build the query and chain freely, while terminal methods like get(), count(), and first() actually hit the database. The performance critical entries are select_related() and prefetch_related(), which collapse the dreaded N+1 query problem into a handful of efficient joins.

Method	Example	Description
all()	`Post.objects.all()`	• Returns QuerySet with all objects • lazily evaluated until accessed or iterated.

The rest of this section is part of the full cheat sheet

Table 3: Field Lookups

Lookups are the suffixes you append after a double underscore to ask precise questions in a filter() — is this field greater than, contained in, case-insensitively equal to, or null? They cover the everyday comparisons (gt, lt, in, range), the text-matching family (contains, startswith, and their i-prefixed case-insensitive cousins), and date-part extraction like year and month. Knowing which ones can use a database index — prefix matches yes, suffix and substring matches no — pays off on large tables.

Lookup	Example	Description
exact	`Post.objects.filter(id__exact=1)`	• Exact match • default lookup when no suffix given • `id=1` is equivalent • case sensitivity is decided by the database's own collation, not Django.

The rest of this section is part of the full cheat sheet

Table 4: Q Objects and Complex Queries

Plain filter() calls can only AND conditions together, so the moment you need OR logic, negation, or grouped precedence you reach for Q objects. They wrap conditions into composable pieces you can combine with |, &, and ~, even building them up dynamically in a loop. This is the toolkit for translating "published OR featured, but not drafts" into a single query.

Pattern	Example	Description
Q() with OR	`Post.objects.filter(Q(status='published') \| Q(status='featured'))`	• Combines conditions with OR logic • regular `filter()` only supports AND.

The rest of this section is part of the full cheat sheet

Table 1: Model Fields

Field	Example	Description
CharField	`name = models.CharField(max_length=200)`	• Required `max_length` • stores short text strings • rendered as `<input type="text">` in forms.
TextField	`description = models.TextField()`	• Unlimited text storage • rendered as `<textarea>` in forms • no `max_length` validation.
IntegerField	`age = models.IntegerField()`	• Stores integers from -2147483648 to 2147483647 • use `BigIntegerField` for larger range.
FloatField	`price = models.FloatField()`	• Stores floating-point numbers as Python `float` • use `DecimalField` for financial precision.
DecimalField	`amount = models.DecimalField(max_digits=10, decimal_places=2)`	• Required `max_digits` and `decimal_places` • precise decimal storage for financial data • avoids float precision issues.
BooleanField	`is_active = models.BooleanField(default=True)`	• Stores True/False • rendered as checkbox • use `null=True` for three-state nullable boolean (NullBooleanField was removed in Django 4.0).
DateField	`signup_date = models.DateField(auto_now_add=True)`	• Stores a date • `auto_now` updates on every save, `auto_now_add` sets once on creation.
DateTimeField	`created_at = models.DateTimeField(auto_now_add=True)`	• Stores date and time with timezone awareness if `USE_TZ=True` • uses Python `datetime.datetime`.
EmailField	`email = models.EmailField(unique=True)`	• CharField with email validation • `max_length` defaults to 254 • uses `EmailValidator`.
URLField	`website = models.URLField()`	• CharField with URL validation • `max_length` defaults to 200 • validates using `URLValidator`.
JSONField	`data = models.JSONField(default=dict)`	• Stores JSON-encoded data • supports native database JSON types • queryable with key lookups.
SlugField	`slug = models.SlugField(unique=True)`	• CharField for URL slugs • allows letters, numbers, underscores, hyphens • typically paired with `prepopulated_fields` in admin.
UUIDField	`id = models.UUIDField(primary_key=True, default=uuid.uuid4)`	• Stores a universally unique identifier • useful for public-facing IDs instead of sequential integers.
ForeignKey	`author = models.ForeignKey(User, on_delete=models.CASCADE)`	• Many-to-one relationship • requires `on_delete` (CASCADE, PROTECT, SET_NULL, SET_DEFAULT, DO_NOTHING) • creates database index automatically.
ManyToManyField	`tags = models.ManyToManyField(Tag)`	• Many-to-many relationship • creates intermediary table automatically • use `through` for custom intermediary model.
OneToOneField	`profile = models.OneToOneField(User, on_delete=models.CASCADE)`	• One-to-one relationship • similar to ForeignKey with `unique=True` • useful for extending a model without inheritance.
FileField	`document = models.FileField(upload_to='docs/')`	• Handles file uploads • `upload_to` defines storage path relative to `MEDIA_ROOT`.
ImageField	`photo = models.ImageField(upload_to='photos/')`	• FileField with image validation • requires Pillow library • optionally stores width and height.
GeneratedField	`area = models.GeneratedField(` `expression=F('side') * F('side'),` `output_field=models.IntegerField(),` `db_persist=True)`	• Database-computed column (Django 5.0+) • always derived from other fields at database level • `db_persist=True` stores value; `False` computes on read.

Table 2: QuerySet Methods

Method	Example	Description
all()	`Post.objects.all()`	• Returns QuerySet with all objects • lazily evaluated until accessed or iterated.

Table 3: Field Lookups

Lookup	Example	Description
exact	`Post.objects.filter(id__exact=1)`	• Exact match • default lookup when no suffix given • `id=1` is equivalent • case sensitivity is decided by the database's own collation, not Django.

Table 4: Q Objects and Complex Queries

Pattern	Example	Description
Q() with OR	`Post.objects.filter(Q(status='published') \| Q(status='featured'))`	• Combines conditions with OR logic • regular `filter()` only supports AND.