_meta APILink to this heading#Tá an tsamhail _meta API ag croílár an ORM Django. Cuireann sé ar chumas codanna eile den chóras mar chuardaigh, ceisteanna, foirmeacha agus an riarachán cumais gach samhail a thuiscint. Tá an API inrochtana trí thréith _meta gach aicme samhail, ar shampla é de réad Django.db.Models.Options.Options.
Methods and attributes that it provides can be used to:
\nAisghabháil gach cás réimse de mhúnla
Aisghabháil sampla réimse amháin de mhúnla de réir ainm
Retrieve all fields that compose the primary key of a model
Tugann ainm réimse ar ais.
\nIs féidir le field_name` a bheith ina ainm réimse ar an tsamhail, réimse ar mhúnla teibí nó oidhreachta, nó réimse atá sainmhínithe ar mhúnla eile a thugann in iúl don tsamhail. Sa chás deireanach sin, is é an field_name` (in ord rogha) an:attr: ~.foreignkey.related_query_name a shocraíonn an t-úsáideoir, an:attr: ~.foreignKey.related_name atá leagtha amach ag an úsáideoir, nó an t-ainm a ghineann Django go huathoibríoch.
\nHidden fields, fields with hidden=True, cannot be retrieved by name.
Mura bhfaightear réimse leis an ainm a thugtar a:class: ~django.core.exceptions.fieldDoesNotExist ardófar eisceacht.
\n>>> from django.contrib.auth.models import User\n\n# A field on the model\n>>> User._meta.get_field("username")\n<django.db.models.fields.CharField: username>\n\n# A field from another model that has a relation with the current model\n>>> User._meta.get_field("logentry")\n<ManyToOneRel: admin.logentry>\n\n# A non existent field\n>>> User._meta.get_field("does_not_exist")\nTraceback (most recent call last):\n ...\nFieldDoesNotExist: User has no field named 'does_not_exist'\nTugann sé cúpla réimsí a bhaineann le samhail ar ais. Glacann ``get_fields () ``le dhá pharaiméadar is féidir a úsáid chun na réimsí a chuirtear ar ais a rialú:
\nTrue de réir réamhshocraithe. Cuimsíonn sé go réimsí atá sainithe ar ranganna tuismitheoirí Má tá sé socraithe ar False, ní chuardóidh ``get_fields () ``ach réimsí a dearbhaíodh go díreach ar an tsamhail reatha. Meastar go bhfuil réimsí ó mhúnlaí a dhéanann oidhreacht go díreach ó mhúnlaí teibí nó ó ranganna seachfhreastalaí áitiúla, ní ar an
include_hiddenFalse by default. If set to True, get_fields() will include\nfields with hidden=True.
>>> from django.contrib.auth.models import User\n>>> User._meta.get_fields()\n(<ManyToOneRel: admin.logentry>,\n <django.db.models.fields.AutoField: id>,\n <django.db.models.fields.CharField: password>,\n <django.db.models.fields.DateTimeField: last_login>,\n <django.db.models.fields.BooleanField: is_superuser>,\n <django.db.models.fields.CharField: username>,\n <django.db.models.fields.CharField: first_name>,\n <django.db.models.fields.CharField: last_name>,\n <django.db.models.fields.EmailField: email>,\n <django.db.models.fields.BooleanField: is_staff>,\n <django.db.models.fields.BooleanField: is_active>,\n <django.db.models.fields.DateTimeField: date_joined>,\n <django.db.models.fields.related.ManyToManyField: groups>,\n <django.db.models.fields.related.ManyToManyField: user_permissions>)\n\n# Also include hidden fields.\n>>> User._meta.get_fields(include_hidden=True)\n(<ManyToOneRel: auth.user_groups>,\n <ManyToOneRel: auth.user_user_permissions>,\n <ManyToOneRel: admin.logentry>,\n <django.db.models.fields.AutoField: id>,\n <django.db.models.fields.CharField: password>,\n <django.db.models.fields.DateTimeField: last_login>,\n <django.db.models.fields.BooleanField: is_superuser>,\n <django.db.models.fields.CharField: username>,\n <django.db.models.fields.CharField: first_name>,\n <django.db.models.fields.CharField: last_name>,\n <django.db.models.fields.EmailField: email>,\n <django.db.models.fields.BooleanField: is_staff>,\n <django.db.models.fields.BooleanField: is_active>,\n <django.db.models.fields.DateTimeField: date_joined>,\n <django.db.models.fields.related.ManyToManyField: groups>,\n <django.db.models.fields.related.ManyToManyField: user_permissions>)\nReturns a list of the fields composing the primary key of a model.
\nWhen a CompositePrimaryKey is defined on a model\nit will contain all the fields referenced by it.
from django.db import models\n\n\nclass TenantUser(models.Model):\n pk = models.CompositePrimaryKey("tenant_id", "id")\n tenant_id = models.IntegerField()\n id = models.IntegerField()\n>>> TenantUser._meta.pk_fields\n[\n <django.db.models.fields.IntegerField: tenant_id>,\n <django.db.models.fields.IntegerField: id>\n]\nOtherwise it will contain the single field declared as the primary key of\nthe model, either explicitly with primary_key=True or implicitly as the automatic\nprimary key.
>>> User._meta.pk_fields\n[<django.db.models.fields.AutoField: id>]\n