Topic guide Django shortcut functions

get_object_or_404(klass,*args,**kwargs)[source] aget_object_or_404(klass,*args,**kwargs) : Asynchronous version: aget_object_or_404()

Topic guide Django shortcut functions get_list_or_404()

klass A Model class, a Manager, or a QuerySet instance from which to get the object. *args Q objects. **kwargs Lookup parameters, which should be in the format accepted by get() and filter().

Topic guide Django shortcut functions

get_list_or_404(klass,*args,**kwargs)[source] aget_list_or_404(klass,*args,**kwargs) : Asynchronous version: aget_list_or_404()

Topic guide Django shortcut functions get_list_or_404()

klass A Model, Manager or QuerySet instance from which to get the list. *args Q objects. **kwargs Lookup parameters, which should be in the format accepted by get() and filter().

Topic guide Pagination

Under the hood, all methods of pagination use the Paginator class. It does all the heavy lifting of actually splitting a QuerySet into Page objects.

Topic guide Pagination

Here’s an example using Paginator in a view function to paginate a queryset: In the template list.html, you can include navigation between pages in the same way as in the template for the ListView above.

Topic guide Performance and optimization Understanding laziness

Django is itself quite lazy. A good example of this can be found in the evaluation of a QuerySet. QuerySets are lazy.

Topic guide Security in Django

This can result in records being deleted or data leakage. Django’s querysets are protected from SQL injection since their queries are constructed using query parameterization. A query’s SQL code is defined separately from the query’s parameters.

Topic guide Serializing Django objects

At the highest level, you can serialize data like this: The arguments to the serialize function are the format to serialize the data to (see Serialization formats) and a QuerySet to serialize.

Index

| | | | --- | --- | | - y (LineString attribute) - (Point attribute) - year - field lookup type - year (YearMixin attribute) - year_format (YearMixin attribute) - YEAR_MONTH_FORMAT - setting | - YearArchiveView (built-in class) - …

Internals Django Deprecation Timeline

django.core.paginator.QuerySetPaginator will be removed. A model’s Meta.ordering will no longer affect GROUP BY queries. django.contrib.postgres.fields.FloatRangeField and django.contrib.postgres.forms.FloatRangeField will be removed. The FILE_CHARSET setting will be removed. django.contrib.staticfiles.storage.CachedStaticFilesStorage will be removed. RemoteUserBackend.configure_user() will require request as the first positional argument.

Reference The Django admin site ModelAdmin objects

ModelAdmin.search_help_text : Set search_help_text to specify a descriptive text for the search box which will be displayed below it. ModelAdmin.show_full_result_count : Set show_full_result_count to control whether the full count of objects should be displayed on a filtered admin page (e.g.

Reference PostgreSQL specific aggregation functions General-purpose aggregation functions

classStringAgg(expression,delimiter,distinct=False,filter=None,default=None,order_by=()) : > WARNING: > > Deprecated since version 6.0: The PostgreSQL StringAgg class is deprecated in favor of the > generally available StringAgg class.

Reference Databases SQLite notes

These are triggered when using the iexact or contains filters in querysets. The behavior splits into two cases: For substring matching, all matches are done case-insensitively. That is a filter such as filter(name__contains="aa") will match a name of "Aabb".

Reference Conditional Expressions Advanced queries

What if we want to find out how many clients there are for each account_type?

Reference Model index reference Index options

Index.condition If the table is very large and your queries mostly target a subset of rows, it may be useful to restrict an index to that subset. Specify a condition as a Q.

FAQ FAQ: The admin

Using the same trick of extracting the user from the request, the get_queryset() and has_change_permission() can be used to control the visibility and editability of objects in the admin.

Index

… method) - page_kwarg (django.views.generic.list.MultipleObjectMixin attribute) - page_range (Paginator attribute) - PageNotAnInteger - paginate_by (django.views.generic.list.MultipleObjectMixin attribute) - paginate_orphans (django.views.generic.list.MultipleObjectMixin attribute) - paginate_queryset() (django.views.generic.list.MultipleObjectMixin method) - Paginator (class in django.core.paginator) - paginator (ModelAdmin attribute) - (Page attribute) - (Sitemap attribute) - paginator_class …

Index

… django.contrib.postgres.fields) - RangeWidget (class in django.contrib.postgres.forms) - Rank (class in django.db.models.functions) - RasterField (class in django.contrib.gis.db.models) - raw() (in module django.db.models.query.QuerySet) - (Manager method) - raw_id_fields (InlineModelAdmin attribute) - (ModelAdmin attribute) - RawSQL (class in django.db.models.expressions) - re_path() (in module …

Index

… - setting - SecurityMiddleware (class in django.middleware.security) - seekable() (HttpResponse method) - Select (class in django.forms) - select_for_update() (in module django.db.models.query.QuerySet) - select_on_save (Options attribute) - select_related() (in module django.db.models.query.QuerySet) - select_template() (Engine method) - (in module django.template.loader) - SelectDateWidget …