This document contains all the API references of Field including the\nfield options and field types Django offers.
The following arguments are available to all field types. All are optional.
\nnullLink para este cabeçalho#Se True, o Django irá usar valores “vazios” como NULL no banco de dados. Padrão is False.
Avoid using null on string-based fields such as\nCharField and TextField. The Django convention is to use an\nempty string, not NULL, as the “no data” state for string-based fields. If a\nstring-based field has null=False, empty strings can still be saved for “no\ndata”. If a string-based field has null=True, that means it has two possible\nvalues for “no data”: NULL, and the empty string. In most cases, it’s\nredundant to have two possible values for “no data”. One exception is when a\nCharField has both unique=True and blank=True set. In this\nsituation, null=True is required to avoid unique constraint violations when\nsaving multiple objects with blank values.
For both string-based and non-string-based fields, you will also need to\nset blank=True if you wish to permit empty values in forms, as the\nnull parameter only affects database storage\n(see blank).
blankLink para este cabeçalho#Se True, é permitido o campo estar em “branco”. O padrão é False.
Note that this is different than null. null is\npurely database-related, whereas blank is validation-related. If\na field has blank=True, form validation will allow entry of an empty value.\nIf a field has blank=False, the field will be required.
choicesLink para este cabeçalho#A mapping or iterable in the format described below to use as choices for this\nfield. If choices are given, they’re enforced by\nmodel validation and the default form widget will\nbe a select box with these choices instead of the standard text field.
\nIf a mapping is given, the key element is the actual value to be set on the\nmodel, and the second element is the human readable name. For example:
\nYEAR_IN_SCHOOL_CHOICES = {\n "FR": "Freshman",\n "SO": "Sophomore",\n "JR": "Junior",\n "SR": "Senior",\n "GR": "Graduate",\n}\nYou can also pass a sequence consisting itself of iterables of exactly\ntwo items (e.g. [(A1, B1), (A2, B2), …]). The first element in each tuple\nis the actual value to be set on the model, and the second element is the\nhuman-readable name. For example:
YEAR_IN_SCHOOL_CHOICES = [\n ("FR", "Freshman"),\n ("SO", "Sophomore"),\n ("JR", "Junior"),\n ("SR", "Senior"),\n ("GR", "Graduate"),\n]\nchoices can also be defined as a callable that expects no arguments and\nreturns any of the formats described above. For example:
def get_currencies():\n return {i: i for i in settings.CURRENCIES}\n\n\nclass Expense(models.Model):\n amount = models.DecimalField(max_digits=10, decimal_places=2)\n currency = models.CharField(max_length=3, choices=get_currencies)\nPassing a callable for choices can be particularly handy when, for example,\nthe choices are:
the result of I/O-bound operations (which could potentially be cached), such\nas querying a table in the same or an external database, or accessing the\nchoices from a static file.
a list that is mostly stable but could vary from time to time or from\nproject to project. Examples in this category are using third-party apps that\nprovide a well-known inventory of values, such as currencies, countries,\nlanguages, time zones, etc.
Generally, it’s best to define choices inside a model class, and to\ndefine a suitably-named constant for each value:
\nfrom django.db import models\n\n\nclass Student(models.Model):\n FRESHMAN = "FR"\n SOPHOMORE = "SO"\n JUNIOR = "JR"\n SENIOR = "SR"\n GRADUATE = "GR"\n YEAR_IN_SCHOOL_CHOICES = {\n FRESHMAN: "Freshman",\n SOPHOMORE: "Sophomore",\n JUNIOR: "Junior",\n SENIOR: "Senior",\n GRADUATE: "Graduate",\n }\n year_in_school = models.CharField(\n max_length=2,\n choices=YEAR_IN_SCHOOL_CHOICES,\n default=FRESHMAN,\n )\n\n def is_upperclass(self):\n return self.year_in_school in {self.JUNIOR, self.SENIOR}\nThough you can define a choices list outside of a model class and then\nrefer to it, defining the choices and names for each choice inside the\nmodel class keeps all of that information with the class that uses it,\nand helps reference the choices (e.g, Student.SOPHOMORE\nwill work anywhere that the Student model has been imported).
You can also collect your available choices into named groups that can\nbe used for organizational purposes:
\nMEDIA_CHOICES = {\n "Audio": {\n "vinyl": "Vinyl",\n "cd": "CD",\n },\n "Video": {\n "vhs": "VHS Tape",\n "dvd": "DVD",\n },\n "unknown": "Unknown",\n}\nThe key of the mapping is the name to apply to the group and the value is the\nchoices inside that group, consisting of the field value and a human-readable\nname for an option. Grouped options may be combined with ungrouped options\nwithin a single mapping (such as the "unknown" option in this example).
You can also use a sequence, e.g. a list of 2-tuples:
\nMEDIA_CHOICES = [\n (\n "Audio",\n (\n ("vinyl", "Vinyl"),\n ("cd", "CD"),\n ),\n ),\n (\n "Video",\n (\n ("vhs", "VHS Tape"),\n ("dvd", "DVD"),\n ),\n ),\n ("unknown", "Unknown"),\n]\nNote that choices can be any sequence object – not necessarily a list or\ntuple. This lets you construct choices dynamically. But if you find yourself\nhacking choices to be dynamic, you’re probably better off using\na proper database table with a ForeignKey. choices is\nmeant for static data that doesn’t change much, if ever.
For each model field that has choices set, Django will normalize\nthe choices to a list of 2-tuples and add a method to retrieve the\nhuman-readable name for the field’s current value. See\nget_FOO_display() in the database API\ndocumentation.
Unless blank=False is set on the field along with a\ndefault then a label containing "---------" will be rendered\nwith the select box. To override this behavior, add a tuple to choices\ncontaining None; e.g. (None, 'Your String For Display').\nAlternatively, you can use an empty string instead of None where this makes\nsense - such as on a CharField.
In addition, Django provides enumeration types that you can subclass to define\nchoices in a concise way:
\nfrom django.utils.translation import gettext_lazy as _\n\n\nclass Student(models.Model):\n class YearInSchool(models.TextChoices):\n FRESHMAN = "FR", _("Freshman")\n SOPHOMORE = "SO", _("Sophomore")\n JUNIOR = "JR", _("Junior")\n SENIOR = "SR", _("Senior")\n GRADUATE = "GR", _("Graduate")\n\n year_in_school = models.CharField(\n max_length=2,\n choices=YearInSchool,\n default=YearInSchool.FRESHMAN,\n )\n\n def is_upperclass(self):\n return self.year_in_school in {\n self.YearInSchool.JUNIOR,\n self.YearInSchool.SENIOR,\n }\nThese work similar to enum from Python’s standard library, but with some\nmodifications:
Enum member values are a tuple of arguments to use when constructing the\nconcrete data type. Django supports adding an extra string value to the end\nof this tuple to be used as the human-readable name, or label. The\nlabel can be a lazy translatable string. Thus, in most cases, the member\nvalue will be a (value, label) 2-tuple. See below for an example\nof subclassing choices using a more complex\ndata type. If a tuple is not provided, or the last item is not a (lazy)\nstring, the label is automatically generated from the member name.
A .label property is added on values, to return the human-readable name.
A number of custom properties are added to the enumeration classes –\n.choices, .labels, .values, and .names – to make it easier\nto access lists of those separate parts of the enumeration.
The use of enum.unique() is enforced to ensure that values cannot be\ndefined multiple times. This is unlikely to be expected in choices for a\nfield.
Note that using YearInSchool.SENIOR, YearInSchool['SENIOR'], or\nYearInSchool('SR') to access or lookup enum members work as expected, as do\nthe .name and .value properties on the members.
If you don’t need to have the human-readable names translated, you can have\nthem inferred from the member name (replacing underscores with spaces and using\ntitle-case):
\n>>> class Vehicle(models.TextChoices):\n... CAR = "C"\n... TRUCK = "T"\n... JET_SKI = "J"\n...\n>>> Vehicle.JET_SKI.label\n'Jet Ski'\nSince the case where the enum values need to be integers is extremely common,\nDjango provides an IntegerChoices class. For example:
class Card(models.Model):\n class Suit(models.IntegerChoices):\n DIAMOND = 1\n SPADE = 2\n HEART = 3\n CLUB = 4\n\n suit = models.IntegerField(choices=Suit)\nIt is also possible to make use of the Enum Functional API with the caveat\nthat labels are automatically generated as highlighted above:
\n>>> MedalType = models.TextChoices("MedalType", "GOLD SILVER BRONZE")\n>>> MedalType.choices\n[('GOLD', 'Gold'), ('SILVER', 'Silver'), ('BRONZE', 'Bronze')]\n>>> Place = models.IntegerChoices("Place", "FIRST SECOND THIRD")\n>>> Place.choices\n[(1, 'First'), (2, 'Second'), (3, 'Third')]\nIf you require support for a concrete data type other than int or str,\nyou can subclass Choices and the required concrete data type, e.g.\ndate for use with DateField:
class MoonLandings(datetime.date, models.Choices):\n APOLLO_11 = 1969, 7, 20, "Apollo 11 (Eagle)"\n APOLLO_12 = 1969, 11, 19, "Apollo 12 (Intrepid)"\n APOLLO_14 = 1971, 2, 5, "Apollo 14 (Antares)"\n APOLLO_15 = 1971, 7, 30, "Apollo 15 (Falcon)"\n APOLLO_16 = 1972, 4, 21, "Apollo 16 (Orion)"\n APOLLO_17 = 1972, 12, 11, "Apollo 17 (Challenger)"\nThere are some additional caveats to be aware of:
\nEnumeration types do not support named groups.
Because an enumeration with a concrete data type requires all values to match\nthe type, overriding the blank label\ncannot be achieved by creating a member with a value of None. Instead,\nset the __empty__ attribute on the class:
class Answer(models.IntegerChoices):\n NO = 0, _("No")\n YES = 1, _("Yes")\n\n __empty__ = _("(Unknown)")\ndb_columnLink para este cabeçalho#The name of the database column to use for this field. If this isn’t given,\nDjango will use the field’s name.
\nIf your database column name is an SQL reserved word, or contains\ncharacters that aren’t allowed in Python variable names – notably, the\nhyphen – that’s OK. Django quotes column and table names behind the\nscenes.
\ndb_commentLink para este cabeçalho#The comment on the database column to use for this field. It is useful for\ndocumenting fields for individuals with direct database access who may not be\nlooking at your Django code. For example:
\npub_date = models.DateTimeField(\n db_comment="Date and time when the article was published",\n)\ndb_defaultLink para este cabeçalho#The database-computed default value for this field. This can be a literal value\nor a database function, such as Now:
created = models.DateTimeField(db_default=Now())\nMore complex expressions can be used, as long as they are made from literals\nand database functions:
\nmonth_due = models.DateField(\n db_default=TruncMonth(\n Now() + timedelta(days=90),\n output_field=models.DateField(),\n )\n)\nDatabase defaults cannot reference other fields or models. For example, this is\ninvalid:
\nend = models.IntegerField(db_default=F("start") + 50)\nIf both db_default and Field.default are set, default will take\nprecedence when creating instances in Python code. db_default will still be\nset at the database level and will be used when inserting rows outside of the\nORM or when adding a new field in a migration.
If a field has a db_default without a default set and no value is\nassigned to the field, a DatabaseDefault object is returned as the field\nvalue on unsaved model instances. The actual value for the field is determined\nby the database when the model instance is saved.
db_indexLink para este cabeçalho#If True, a database index will be created for this field.
db_tablespaceLink para este cabeçalho#The name of the database tablespace to use for\nthis field’s index, if this field is indexed. The default is the project’s\nDEFAULT_INDEX_TABLESPACE setting, if set, or the\ndb_tablespace of the model, if any. If the backend doesn’t\nsupport tablespaces for indexes, this option is ignored.
defaultLink para este cabeçalho#O valor padrão para o campo. Este pode ser um valor ou um objeto “callable”. Se “callable” ele será chamado cada vez que um novo objeto for criado.
\nThe default can’t be a mutable object (model instance, list, set, etc.),\nas a reference to the same instance of that object would be used as the default\nvalue in all new model instances. Instead, wrap the desired default in a\ncallable. For example, if you want to specify a default dict for\nJSONField, use a function:
def contact_default():\n return {"email": "to1@example.com"}\n\n\ncontact_info = JSONField("ContactInfo", default=contact_default)\nlambdas can’t be used for field options like default because they\ncan’t be serialized by migrations. See that\ndocumentation for other caveats.
For fields like ForeignKey that map to model instances, defaults\nshould be the value of the field they reference (pk unless\nto_field is set) instead of model instances.
The default value is used when new model instances are created and a value\nisn’t provided for the field. When the field is a primary key, the default is\nalso used when the field is set to None.
The default value can also be set at the database level with\nField.db_default.
editableLink para este cabeçalho#If False, the field will not be displayed in the admin or any other\nModelForm. It will also be skipped during model\nvalidation. Default is True.
error_messagesLink para este cabeçalho#The error_messages argument lets you override the default messages that the\nfield will raise. Pass in a dictionary with keys matching the error messages you\nwant to override.
Error message keys include null, blank, invalid, invalid_choice,\nunique, and unique_for_date. Additional error message keys are\nspecified for each field in the Field types section below.
These error messages often don’t propagate to forms. See\nConsiderations regarding model’s error_messages.
\nhelp_textLink para este cabeçalho#Texto extra de ajuda para ser mostrado com o “widget” do formulário. É útil para documentar mesmo que seu campo não seja usado em um formulário.
\nNote that this value is not HTML-escaped in automatically-generated\nforms. This lets you include HTML in help_text if you so\ndesire. For example:
help_text = "Please use the following format: <em>YYYY-MM-DD</em>."\nAlternatively you can use plain text and\ndjango.utils.html.escape() to escape any HTML special characters. Ensure\nthat you escape any help text that may come from untrusted users to avoid a\ncross-site scripting attack.
primary_keyLink para este cabeçalho#Se True, este campo será a chave-primária do seu modelo.
If you don’t specify primary_key=True for any field in your model and have\nnot defined a composite primary key, Django will automatically add a field to\nhold the primary key. So, you don’t need to set primary_key=True on any of\nyour fields unless you want to override the default primary-key behavior. The\ntype of auto-created primary key fields can be specified per app in\nAppConfig.default_auto_field\nor globally in the DEFAULT_AUTO_FIELD setting. For more, see\nCampos chave-primária automáticos..
primary_key=True implies null=False and\nunique=True. Only one field per model can set\nprimary_key=True. Composite primary keys must be defined using\nCompositePrimaryKey instead of setting this flag to True for all\nfields to maintain this invariant.
The primary key field is read-only. If you change the value of the primary\nkey on an existing object and then save it, a new object will be created\nalongside the old one.
\nThe primary key field is set to None when\ndeleting an object.
uniqueLink para este cabeçalho#Se True, este campo deve ser único dentro da tabela
This is enforced at the database level and by model validation. If\nyou try to save a model with a duplicate value in a unique\nfield, a django.db.IntegrityError will be raised by the model’s\nsave() method.
This option is valid on all field types except ManyToManyField and\nOneToOneField.
Note that when unique is True, you don’t need to specify\ndb_index, because unique implies the creation of an index.
unique_for_dateLink para este cabeçalho#Set this to the name of a DateField or DateTimeField to\nrequire that this field be unique for the value of the date field.
For example, if you have a field title that has\nunique_for_date="pub_date", then Django wouldn’t allow the entry of two\nrecords with the same title and pub_date.
Note that if you set this to point to a DateTimeField, only the date\nportion of the field will be considered. Besides, when USE_TZ is\nTrue, the check will be performed in the current time zone at the time the object gets saved.
This is enforced by Model.validate_unique() during model validation\nbut not at the database level. If any unique_for_date constraint\ninvolves fields that are not part of a ModelForm (for\nexample, if one of the fields is listed in exclude or has\neditable=False), Model.validate_unique() will\nskip validation for that particular constraint.
unique_for_monthLink para este cabeçalho#Like unique_for_date, but requires the field to be unique with\nrespect to the month.
unique_for_yearLink para este cabeçalho#Like unique_for_date and unique_for_month.
verbose_nameLink para este cabeçalho#A human-readable name for the field. If the verbose name isn’t given, Django\nwill automatically create it using the field’s attribute name, converting\nunderscores to spaces. See Verbose field names.
\nvalidatorsLink para este cabeçalho#A list of validators to run for this field. See the validators\ndocumentation for more information.
\nAutoFieldLink para este cabeçalho#An IntegerField that automatically increments\naccording to available IDs. You usually won’t need to use this directly; a\nprimary key field will automatically be added to your model if you don’t specify\notherwise. See Campos chave-primária automáticos..
BigAutoFieldLink para este cabeçalho#A 64-bit integer, much like an AutoField except that it is\nguaranteed to fit numbers from 1 to 9223372036854775807.
BigIntegerFieldLink para este cabeçalho#A 64-bit integer, much like an IntegerField except that it is\nguaranteed to fit numbers from -9223372036854775808 to\n9223372036854775807. The default form widget for this field is a\nNumberInput.
BinaryFieldLink para este cabeçalho#A field to store raw binary data. It can be assigned bytes,\nbytearray, or memoryview.
By default, BinaryField sets editable to False, in which\ncase it can’t be included in a ModelForm.
Optional. The maximum length (in bytes) of the field. The maximum length is\nenforced in Django’s validation using\nMaxLengthValidator.
BooleanFieldLink para este cabeçalho#A true/false field.
\nThe default form widget for this field is CheckboxInput,\nor NullBooleanSelect if null=True.
The default value of BooleanField is None when Field.default\nisn’t defined.
CompositePrimaryKeyLink para este cabeçalho#A virtual field used for defining a composite primary key.
\nThis field must be defined as the model’s pk attribute. If present, Django\nwill create the underlying model table with a composite primary key.
The *field_names argument is a list of positional field names that compose\nthe primary key.
See Composite primary keys for more details.
\nCharFieldLink para este cabeçalho#A string field, for small- to large-sized strings.
\nFor large amounts of text, use TextField.
The default form widget for this field is a TextInput.
CharField has the following extra arguments:
The maximum length (in characters) of the field. The max_length\nis enforced at the database level and in Django’s validation using\nMaxLengthValidator. It’s required for all\ndatabase backends included with Django except PostgreSQL and SQLite, which\nsupports unlimited VARCHAR columns.
Optional. The database collation name of the field.
\n\n\nDateFieldLink para este cabeçalho#A date, represented in Python by a datetime.date instance. Has a few extra,\noptional arguments:
Automatically set the field to now every time the object is saved. Useful\nfor “last-modified” timestamps. Note that the current date is always\nused; it’s not just a default value that you can override.
\nThe field is only automatically updated when calling Model.save(). The field isn’t updated when making updates\nto other fields in other ways such as QuerySet.update(), though you can specify a custom\nvalue for the field in an update like that.
Automatically set the field to now when the object is first created. Useful\nfor creation of timestamps. Note that the current date is always used;\nit’s not just a default value that you can override. So even if you\nset a value for this field when creating the object, it will be ignored.\nIf you want to be able to modify this field, set the following instead of\nauto_now_add=True:
For DateField: default=date.today - from\ndatetime.date.today()
For DateTimeField: default=timezone.now - from\ndjango.utils.timezone.now()
The default form widget for this field is a\nDateInput. The admin adds a JavaScript calendar,\nand a shortcut for “Today”. Includes an additional invalid_date error\nmessage key.
The options auto_now_add, auto_now, and default are mutually exclusive.\nAny combination of these options will result in an error.
DateTimeFieldLink para este cabeçalho#A date and time, represented in Python by a datetime.datetime instance.\nTakes the same extra arguments as DateField.
The default form widget for this field is a single\nDateTimeInput. The admin uses two separate\nTextInput widgets with JavaScript shortcuts.
DecimalFieldLink para este cabeçalho#A fixed-precision decimal number, represented in Python by a\nDecimal instance. It validates the input using\nDecimalValidator.
Has the following required arguments:
\nThe maximum number of digits allowed in the number. Note that this number\nmust be greater than or equal to decimal_places.
The number of decimal places to store with the number.
\nFor example, to store numbers up to 999.99 with a resolution of 2 decimal\nplaces, you’d use:
models.DecimalField(..., max_digits=5, decimal_places=2)\nAnd to store numbers up to approximately one billion with a resolution of 10\ndecimal places:
\nmodels.DecimalField(..., max_digits=19, decimal_places=10)\nThe default form widget for this field is a NumberInput\nwhen localize is False or\nTextInput otherwise.
DurationFieldLink para este cabeçalho#A field for storing periods of time - modeled in Python by\ntimedelta. When used on PostgreSQL, the data type\nused is an interval and on Oracle the data type is INTERVAL DAY(9) TO\nSECOND(6). Otherwise a bigint of microseconds is used.
EmailFieldLink para este cabeçalho#A CharField that checks that the value is a valid email address using\nEmailValidator.
FileFieldLink para este cabeçalho#A file-upload field.
\n\nHas the following optional arguments:
\nThis attribute provides a way of setting the upload directory and file name,\nand can be set in two ways. In both cases, the value is passed to the\nStorage.save() method.
If you specify a string value or a Path, it may contain\nstrftime() formatting, which will be replaced by the date/time\nof the file upload (so that uploaded files don’t fill up the given\ndirectory). For example:
class MyModel(models.Model):\n # file will be uploaded to MEDIA_ROOT/uploads\n upload = models.FileField(upload_to="uploads/")\n # or...\n # file will be saved to MEDIA_ROOT/uploads/2015/01/30\n upload = models.FileField(upload_to="uploads/%Y/%m/%d/")\nIf you are using the default\nFileSystemStorage, the string value\nwill be appended to your MEDIA_ROOT path to form the location on\nthe local filesystem where uploaded files will be stored. If you are using\na different storage, check that storage’s documentation to see how it\nhandles upload_to.
upload_to may also be a callable, such as a function. This will be\ncalled to obtain the upload path, including the filename. This callable must\naccept two arguments and return a Unix-style path (with forward slashes)\nto be passed along to the storage system. The two arguments are:
Argument | \nDescrição | \n
|---|---|
| \nAn instance of the model where the\n In most cases, this object will not have been\nsaved to the database yet, so if it uses the\ndefault | \n
| \nThe filename that was originally given to the\nfile. This may or may not be taken into account\nwhen determining the final destination path. | \n
Por exemplo:
\ndef user_directory_path(instance, filename):\n # file will be uploaded to MEDIA_ROOT/user_<id>/<filename>\n return "user_{0}/{1}".format(instance.user.id, filename)\n\n\nclass MyModel(models.Model):\n upload = models.FileField(upload_to=user_directory_path)\nA storage object, or a callable which returns a storage object. This\nhandles the storage and retrieval of your files. See Gerenciando arquivos\nfor details on how to provide this object.
\nThe default form widget for this field is a\nClearableFileInput.
Using a FileField or an ImageField (see below) in a model\ntakes a few steps:
Em seu arquivo de configurações, você precisará definir MEDIA_ROOT como o caminho completo para um diretório onde você gostaria que o Django armazenasse os arquivos enviados. (Para desempenho, esses arquivos não são armazenados no banco de dados.) Defina MEDIA_URL como a URL pública base desse diretório. Certifique-se de que este diretório seja gravável pela conta de usuário do servidor web.
Add the FileField or ImageField to your model, defining\nthe upload_to option to specify a subdirectory of\nMEDIA_ROOT to use for uploaded files.
All that will be stored in your database is a path to the file\n(relative to MEDIA_ROOT). You’ll most likely want to use the\nconvenience url attribute\nprovided by Django. For example, if your ImageField is called\nmug_shot, you can get the absolute path to your image in a template with\n{{ object.mug_shot.url }}.
For example, say your MEDIA_ROOT is set to '/home/media', and\nupload_to is set to 'photos/%Y/%m/%d'. The '%Y/%m/%d'\npart of upload_to is strftime() formatting;\n'%Y' is the four-digit year, '%m' is the two-digit month and '%d' is\nthe two-digit day. If you upload a file on Jan. 15, 2007, it will be saved in\nthe directory /home/media/photos/2007/01/15.
If you wanted to retrieve the uploaded file’s on-disk filename, or the file’s\nsize, you could use the name and\nsize attributes respectively; for more\ninformation on the available attributes and methods, see the\nFile class reference and the Gerenciando arquivos\ntopic guide.
The uploaded file’s relative URL can be obtained using the\nurl attribute. Internally,\nthis calls the url() method of the\nunderlying Storage class.
Note that whenever you deal with uploaded files, you should pay close attention\nto where you’re uploading them and what type of files they are, to avoid\nsecurity holes. Validate all uploaded files so that you’re sure the files are\nwhat you think they are. For example, if you blindly let somebody upload files,\nwithout validation, to a directory that’s within your web server’s document\nroot, then somebody could upload a CGI or PHP script and execute that script by\nvisiting its URL on your site. Don’t allow that.
\nAlso note that even an uploaded HTML file, since it can be executed by the\nbrowser (though not by the server), can pose security threats that are\nequivalent to XSS or CSRF attacks.
\nFileField instances are created in your database as varchar\ncolumns with a default max length of 100 characters. As with other fields, you\ncan change the maximum length using the max_length argument.
FileField and FieldFileLink para este cabeçalho#When you access a FileField on a model, you are\ngiven an instance of FieldFile as a proxy for accessing the underlying\nfile.
The API of FieldFile mirrors that of File,\nwith one key difference: The object wrapped by the class is not necessarily a\nwrapper around Python’s built-in file object. Instead, it is a wrapper around\nthe result of the Storage.open()\nmethod, which may be a File object, or it may be a\ncustom storage’s implementation of the File API.
In addition to the API inherited from File such as\nread() and write(), FieldFile includes several methods that\ncan be used to interact with the underlying file:
The name of the file including the relative path from the root of the\nStorage of the associated\nFileField.
A read-only property to access the file’s local filesystem path by calling the\npath() method of the underlying\nStorage class.
The result of the underlying Storage.size() method.
A read-only property to access the file’s relative URL by calling the\nurl() method of the underlying\nStorage class.
Opens or reopens the file associated with this instance in the specified\nmode. Unlike the standard Python open() method, it doesn’t return a\nfile descriptor.
Since the underlying file is opened implicitly when accessing it, it may be\nunnecessary to call this method except to reset the pointer to the underlying\nfile or to change the mode.
Behaves like the standard Python file.close() method and closes the file\nassociated with this instance.
This method takes a filename and file contents and passes them to the storage\nclass for the field, then associates the stored file with the model field.\nIf you want to manually associate file data with\nFileField instances on your model, the save()\nmethod is used to persist that file data.
Takes two required arguments: name which is the name of the file, and\ncontent which is an object containing the file’s contents. The\noptional save argument controls whether or not the model instance is\nsaved after the file associated with this field has been altered. Defaults to\nTrue.
Note that the content argument should be an instance of\ndjango.core.files.File, not Python’s built-in file object.\nYou can construct a File from an existing\nPython file object like this:
from django.core.files import File\n\n# Open an existing file using Python's built-in open()\nf = open("/path/to/hello.world")\nmyfile = File(f)\nOr you can construct one from a Python string like this:
\nfrom django.core.files.base import ContentFile\n\nmyfile = ContentFile("hello world")\nFor more information, see Gerenciando arquivos.
\nDeletes the file associated with this instance and clears all attributes on\nthe field. Note: This method will close the file if it happens to be open when\ndelete() is called.
The optional save argument controls whether or not the model instance is\nsaved after the file associated with this field has been deleted. Defaults to\nTrue.
Note that when a model is deleted, related files are not deleted. If you need\nto cleanup orphaned files, you’ll need to handle it yourself (for instance,\nwith a custom management command that can be run manually or scheduled to run\nperiodically via e.g. cron).
\nFilePathFieldLink para este cabeçalho#A CharField whose choices are limited to the filenames in a certain\ndirectory on the filesystem. Has some special arguments, of which the first is\nrequired:
Required. The absolute filesystem path to a directory from which this\nFilePathField should get its choices. Example: "/home/images".
path may also be a callable, such as a function to dynamically set the\npath at runtime. Example:
import os\nfrom django.conf import settings\nfrom django.db import models\n\n\ndef images_path():\n return os.path.join(settings.LOCAL_FILE_DIR, "images")\n\n\nclass MyModel(models.Model):\n file = models.FilePathField(path=images_path)\nOptional. A regular expression, as a string, that FilePathField\nwill use to filter filenames. Note that the regex will be applied to the\nbase filename, not the full path. Example: "foo.*\\.txt$", which will\nmatch a file called foo23.txt but not bar.txt or foo23.png.
Optional. Either True or False. Default is False. Specifies\nwhether all subdirectories of path should be included
Optional. Either True or False. Default is True. Specifies\nwhether files in the specified location should be included. Either this or\nallow_folders must be True.
Optional. Either True or False. Default is False. Specifies\nwhether folders in the specified location should be included. Either this\nor allow_files must be True.
The one potential gotcha is that match applies to the\nbase filename, not the full path. So, this example:
FilePathField(path="/home/images", match="foo.*", recursive=True)\n…will match /home/images/foo.png but not /home/images/foo/bar.png\nbecause the match applies to the base filename\n(foo.png and bar.png).
FilePathField instances are created in your database as varchar\ncolumns with a default max length of 100 characters. As with other fields, you\ncan change the maximum length using the max_length argument.
FloatFieldLink para este cabeçalho#A floating-point number represented in Python by a float instance.
The default form widget for this field is a NumberInput\nwhen localize is False or\nTextInput otherwise.
GeneratedFieldLink para este cabeçalho#A field that is always computed based on other fields in the model. This field\nis managed and updated by the database itself. Uses the GENERATED ALWAYS\nSQL syntax.
There are two kinds of generated columns: stored and virtual. A stored\ngenerated column is computed when it is written (inserted or updated) and\noccupies storage as if it were a regular column. A virtual generated column\noccupies no storage and is computed when it is read. Thus, a virtual generated\ncolumn is similar to a view and a stored generated column is similar to a\nmaterialized view.
\nAn Expression used by the database to automatically set the field\nvalue each time the model is changed.
The expressions should be deterministic and only reference fields within\nthe model (in the same database table). Generated fields cannot reference\nother generated fields. Database backends can impose further restrictions.
\nA model field instance to define the field’s data type.
\nDetermines if the database column should occupy storage as if it were a\nreal column. If False, the column acts as a virtual column and does\nnot occupy database storage space.
PostgreSQL only supports persisted columns. Oracle only supports virtual\ncolumns.
\nGenericIPAddressFieldLink para este cabeçalho#An IPv4 or IPv6 address, in string format (e.g. 192.0.2.30 or\n2a02:42fe::4). The default form widget for this field is a\nTextInput.
The IPv6 address normalization follows RFC 4291 Section 2.2 section 2.2,\nincluding using the IPv4 format suggested in paragraph 3 of that section, like\n::ffff:192.0.2.0. For example, 2001:0::0:01 would be normalized to\n2001::1, and ::ffff:0a0a:0a0a to ::ffff:10.10.10.10. All characters\nare converted to lowercase.
Limits valid inputs to the specified protocol.\nAccepted values are 'both' (default), 'IPv4'\nor 'IPv6'. Matching is case insensitive.
Unpacks IPv4 mapped addresses like ::ffff:192.0.2.1.\nIf this option is enabled that address would be unpacked to\n192.0.2.1. Default is disabled. Can only be used\nwhen protocol is set to 'both'.
If you allow for blank values, you have to allow for null values since blank\nvalues are stored as null.
\nImageFieldLink para este cabeçalho#Inherits all attributes and methods from FileField, but also\nvalidates that the uploaded object is a valid image.
In addition to the special attributes that are available for FileField,\nan ImageField also has height and width attributes.
To facilitate querying on those attributes, ImageField has the\nfollowing optional arguments:
Name of a model field which is auto-populated with the height of the image\neach time an image object is set.
\nName of a model field which is auto-populated with the width of the image\neach time an image object is set.
\nRequires the pillow library.
\nImageField instances are created in your database as varchar\ncolumns with a default max length of 100 characters. As with other fields, you\ncan change the maximum length using the max_length argument.
The default form widget for this field is a\nClearableFileInput.
IntegerFieldLink para este cabeçalho#An integer. Values are only allowed between certain (database-dependent)\npoints. Values from -2147483648 to 2147483647 are compatible in all\ndatabases supported by Django.
It uses MinValueValidator and\nMaxValueValidator to validate the input based\non the values that the default database supports.
The default form widget for this field is a NumberInput\nwhen localize is False or\nTextInput otherwise.
JSONFieldLink para este cabeçalho#A field for storing JSON encoded data. In Python the data is represented in its\nPython native format: dictionaries, lists, strings, numbers, booleans and\nNone.
JSONField is supported on MariaDB, MySQL, Oracle, PostgreSQL, and SQLite\n(with the JSON1 extension enabled).
An optional json.JSONEncoder subclass to serialize data types\nnot supported by the standard JSON serializer (e.g. datetime.datetime\nor UUID). For example, you can use the\nDjangoJSONEncoder class.
Defaults to json.JSONEncoder.
An optional json.JSONDecoder subclass to deserialize the value\nretrieved from the database. The value will be in the format chosen by the\ncustom encoder (most often a string). Your deserialization may need to\naccount for the fact that you can’t be certain of the input type. For\nexample, you run the risk of returning a datetime that was actually a\nstring that just happened to be in the same format chosen for\ndatetimes.
Defaults to json.JSONDecoder.
To query JSONField in the database, see Querying JSONField.
PositiveBigIntegerFieldLink para este cabeçalho#Like a PositiveIntegerField, but only allows values under a certain\n(database-dependent) point. Values from 0 to 9223372036854775807 are\ncompatible in all databases supported by Django.
PositiveIntegerFieldLink para este cabeçalho#Like an IntegerField, but must be either positive or zero (0).\nValues are only allowed under a certain (database-dependent) point. Values from\n0 to 2147483647 are compatible in all databases supported by Django.\nThe value 0 is accepted for backward compatibility reasons.
PositiveSmallIntegerFieldLink para este cabeçalho#Like a PositiveIntegerField, but only allows values under a certain\n(database-dependent) point. Values from 0 to 32767 are compatible in\nall databases supported by Django.
SlugFieldLink para este cabeçalho#Slug is a newspaper term. A slug is a short label for something,\ncontaining only letters, numbers, underscores or hyphens. They’re generally used\nin URLs.
\nLike a CharField, you can specify max_length (read the note\nabout database portability and max_length in that section,\ntoo). If max_length is not specified, Django will use a\ndefault length of 50.
Implies setting Field.db_index to True.
It is often useful to automatically prepopulate a SlugField based on the value\nof some other value. You can do this automatically in the admin using\nprepopulated_fields.
It uses validate_slug or\nvalidate_unicode_slug for validation.
If True, the field accepts Unicode letters in addition to ASCII\nletters. Defaults to False.
SmallAutoFieldLink para este cabeçalho#Like an AutoField, but only allows values under a certain\n(database-dependent) limit. Values from 1 to 32767 are compatible in\nall databases supported by Django.
SmallIntegerFieldLink para este cabeçalho#Like an IntegerField, but only allows values under a certain\n(database-dependent) point. Values from -32768 to 32767 are compatible\nin all databases supported by Django.
TextFieldLink para este cabeçalho#A large text field. The default form widget for this field is a\nTextarea.
If you specify a max_length attribute, it will be reflected in the\nTextarea widget of the auto-generated form field.\nHowever it is not enforced at the model or database level. Use a\nCharField for that.
Optional. The database collation name of the field.
\n\n\nTimeFieldLink para este cabeçalho#A time, represented in Python by a datetime.time instance. Accepts the same\nauto-population options as DateField.
The default form widget for this field is a TimeInput.\nThe admin adds some JavaScript shortcuts.
URLFieldLink para este cabeçalho#A CharField for a URL, validated by\nURLValidator.
The default form widget for this field is a URLInput.
Like all CharField subclasses, URLField takes the optional\nmax_length argument. If you don’t specify\nmax_length, a default of 200 is used.
UUIDFieldLink para este cabeçalho#A field for storing universally unique identifiers. Uses Python’s\nUUID class. When used on PostgreSQL and MariaDB 10.7+,\nthis stores in a uuid datatype, otherwise in a char(32).
Universally unique identifiers are a good alternative to AutoField for\nprimary_key. The database will not generate the UUID for you, so\nit is recommended to use default:
import uuid\nfrom django.db import models\n\n\nclass MyUUIDModel(models.Model):\n id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)\n # other fields\nNote that a callable (with the parentheses omitted) is passed to default,\nnot an instance of UUID.
Field is an abstract class that represents a database table column.\nDjango uses fields to create the database table (db_type()), to map\nPython types to database (get_prep_value()) and vice-versa\n(from_db_value()).
A field is thus a fundamental piece in different Django APIs, notably,\nmodels and querysets.
In models, a field is instantiated as a class attribute and represents a\nparticular table column, see Models. It has attributes\nsuch as null and unique, and methods that Django uses to\nmap the field value to database-specific values.
A Field is a subclass of\nRegisterLookupMixin and thus both\nTransform and\nLookup can be registered on it to be used\nin QuerySets (e.g. field_name__exact="foo"). All built-in\nlookups are registered by default.
All of Django’s built-in fields, such as CharField, are particular\nimplementations of Field. If you need a custom field, you can either\nsubclass any of the built-in fields or write a Field from scratch. In\neither case, see Como criar campos de modelo customizado.
A verbose description of the field, e.g. for the\ndjango.contrib.admindocs application.
The description can be of the form:
\ndescription = _("String (up to %(max_length)s)")\nwhere the arguments are interpolated from the field’s __dict__.
A class implementing the descriptor protocol\nthat is instantiated and assigned to the model instance attribute. The\nconstructor must accept a single argument, the Field instance.\nOverriding this class attribute allows for customizing the get and set\nbehavior.
To map a Field to a database-specific type, Django exposes several\nmethods:
Returns a string naming this field for backend specific purposes.\nBy default, it returns the class name.
\nVeja Emulando tipos de campos internos. para uso em campos personalizados.
\nReturns the database column data type for the Field, taking\ninto account the connection.
Veja Tipos de banco de dados personalizados para uso em campos customizados.
\nReturns the database column data type for fields such as ForeignKey\nand OneToOneField that point to the Field, taking\ninto account the connection.
Veja Tipos de banco de dados personalizados para uso em campos customizados.
\nThere are three main situations where Django needs to interact with the\ndatabase backend and fields:
\nwhen it queries the database (Python value -> database backend value)
when it loads data from the database (database backend value -> Python\nvalue)
when it saves to the database (Python value -> database backend value)
When querying, get_db_prep_value() and get_prep_value() are used:
value is the current value of the model’s attribute, and the method\nshould return data in a format that has been prepared for use as a\nparameter in a query.
Veja Convertendo objetos Python para valores em queries para uso.
\nConverts value to a backend-specific value. By default it returns\nvalue if prepared=True and get_prep_value() if is\nFalse.
See Convertendo valores de queries para valores de banco de dados for usage.
\nQuando os dados são carregados, from_db_value() é usado:
Converts a value as returned by the database to a Python object. It is\nthe reverse of get_prep_value().
This method is not used for most built-in fields as the database\nbackend already returns the correct Python type, or the backend itself\ndoes the conversion.
\nexpression is the same as self.
See Convertendo valores para objetos Python for usage.
\n\nQuando salva, pre_save() and get_db_prep_save() é utilizado:
Same as the get_db_prep_value(), but called when the field value\nmust be saved to the database. By default returns\nget_db_prep_value().
Method called prior to get_db_prep_save() to prepare the value\nbefore being saved (e.g. for DateField.auto_now).
model_instance is the instance this field belongs to and add\nis whether the instance is being saved to the database for the first\ntime.
It should return the value of the appropriate attribute from\nmodel_instance for this field. The attribute name is in\nself.attname (this is set up by Field).
Veja Processando valores antes de salvar para usabilidade.
\nFields often receive their values as a different type, either from\nserialization or from forms.
\nConverts the value into the correct Python object. It acts as the\nreverse of value_to_string(), and is also called in\nclean().
See Convertendo valores para objetos Python for usage.
\nBesides saving to the database, the field also needs to know how to\nserialize its value:
\nReturns the field’s value for the given model instance.
\nThis method is often used by value_to_string().
Converts obj to a string. Used to serialize the value of the field.
Veja Convertendo dado do campo para serialização para usabilidade.
\nWhen using model forms, the Field\nneeds to know which form field it should be represented by:
Returns the default django.forms.Field of this field for\nModelForm.
If formfield() is overridden to return None, this field\nis excluded from the ModelForm.
By default, if both form_class and choices_form_class are\nNone, it uses CharField. If the field has\nchoices and choices_form_class\nisn’t specified, it uses TypedChoiceField.
See Especificando o campo de um formulário para o campo de um modelo. for usage.
\nReturns a 4-tuple with enough information to recreate the field:
\nO nome do campo no modelo.
The import path of the field (e.g. "django.db.models.IntegerField").\nThis should be the most portable version, so less specific may be better.
A list of positional arguments.
A dict of keyword arguments.
This method must be added to fields prior to 1.7 to migrate its data\nusing Migrations.
\nField implements the lookup registration API.\nThe API can be used to customize which lookups are available for a field class\nand its instances, and how lookups are fetched from a field.
Every Field instance contains several attributes that allow\nintrospecting its behavior. Use these attributes instead of isinstance\nchecks when you need to write code that depends on a field’s functionality.\nThese attributes can be used together with the Model._meta API to narrow down a search for specific field types.\nCustom model fields should implement these flags.
Boolean flag that indicates if the field was automatically created, such\nas the OneToOneField used by model inheritance.
Boolean flag that indicates if the field has a database column associated\nwith it.
\nBoolean flag that indicates if a field is hidden and should not be returned\nby Options.get_fields() by default. An example is\nthe reverse field for a ForeignKey with a\nrelated_name that starts with '+'.
Boolean flag that indicates if a field contains references to one or\nmore other models for its functionality (e.g. ForeignKey,\nManyToManyField, OneToOneField, etc.).
Returns the model on which the field is defined. If a field is defined on\na superclass of a model, model will refer to the superclass, not the\nclass of the instance.
These attributes are used to query for the cardinality and other details of a\nrelation. These attribute are present on all fields; however, they will only\nhave boolean values (rather than None) if the field is a relation type\n(Field.is_relation=True).
Boolean flag that is True if the field has a many-to-many relation;\nFalse otherwise. The only field included with Django where this is\nTrue is ManyToManyField.
Boolean flag that is True if the field has a many-to-one relation, such\nas a ForeignKey; False otherwise.
Boolean flag that is True if the field has a one-to-many relation, such\nas a GenericRelation or the reverse of a ForeignKey; False\notherwise.
Boolean flag that is True if the field has a one-to-one relation, such\nas a OneToOneField; False otherwise.
Points to the model the field relates to. For example, Author in\nForeignKey(Author, on_delete=models.CASCADE). The related_model for\na GenericForeignKey is always None.