_meta
model¶Options
¶The model _meta
API is at the core of the Django ORM. It enables other
parts of the system such as lookups, queries, forms, and the admin to
understand the capabilities of each model. The API is accessible through
the _meta
attribute of each model class, which is an instance of an
django.db.models.options.Options
object.
Metode-metode yang itu sediakan dapat digunakan untuk:
Options.
get_field
(field_name)¶Returns the field instance given a name of a field.
field_name
can be the name of a field on the model, a field
on an abstract or inherited model, or a field defined on another
model that points to the model. In the latter case, the field_name
will be (in order of preference) the related_query_name
set by the user, the related_name
set by the user, or
the name automatically generated by Django.
Hidden fields
tidak dapat diambil berdasarkan nama.
Jika sebuah bidang dengan nama diberikan tidak ditemukan sebuah pengecualian FieldDoesNotExist
akan dimunculkan.
>>> from django.contrib.auth.models import User
# A field on the model
>>> User._meta.get_field('username')
<django.db.models.fields.CharField: username>
# A field from another model that has a relation with the current model
>>> User._meta.get_field('logentry')
<ManyToOneRel: admin.logentry>
# A non existent field
>>> User._meta.get_field('does_not_exist')
Traceback (most recent call last):
...
FieldDoesNotExist: User has no field named 'does_not_exist'
Options.
get_fields
(include_parents=True, include_hidden=False)¶Returns a tuple of fields associated with a model. get_fields()
accepts
two parameters that can be used to control which fields are returned:
include_parents
True
by default. Recursively includes fields defined on parent
classes. If set to False
, get_fields()
will only search for
fields declared directly on the current model. Fields from models that
directly inherit from abstract models or proxy classes are considered
to be local, not on the parent.include_hidden
False
by default. If set to True
, get_fields()
will include
fields that are used to back other field's functionality. This will
also include any fields that have a related_name
(such
as ManyToManyField
, or
ForeignKey
) that start with a "+".>>> from django.contrib.auth.models import User
>>> User._meta.get_fields()
(<ManyToOneRel: admin.logentry>,
<django.db.models.fields.AutoField: id>,
<django.db.models.fields.CharField: password>,
<django.db.models.fields.DateTimeField: last_login>,
<django.db.models.fields.BooleanField: is_superuser>,
<django.db.models.fields.CharField: username>,
<django.db.models.fields.CharField: first_name>,
<django.db.models.fields.CharField: last_name>,
<django.db.models.fields.EmailField: email>,
<django.db.models.fields.BooleanField: is_staff>,
<django.db.models.fields.BooleanField: is_active>,
<django.db.models.fields.DateTimeField: date_joined>,
<django.db.models.fields.related.ManyToManyField: groups>,
<django.db.models.fields.related.ManyToManyField: user_permissions>)
# Also include hidden fields.
>>> User._meta.get_fields(include_hidden=True)
(<ManyToOneRel: auth.user_groups>,
<ManyToOneRel: auth.user_user_permissions>,
<ManyToOneRel: admin.logentry>,
<django.db.models.fields.AutoField: id>,
<django.db.models.fields.CharField: password>,
<django.db.models.fields.DateTimeField: last_login>,
<django.db.models.fields.BooleanField: is_superuser>,
<django.db.models.fields.CharField: username>,
<django.db.models.fields.CharField: first_name>,
<django.db.models.fields.CharField: last_name>,
<django.db.models.fields.EmailField: email>,
<django.db.models.fields.BooleanField: is_staff>,
<django.db.models.fields.BooleanField: is_active>,
<django.db.models.fields.DateTimeField: date_joined>,
<django.db.models.fields.related.ManyToManyField: groups>,
<django.db.models.fields.related.ManyToManyField: user_permissions>)
Apr 06, 2021