{"title":"Caidrimh duine le duine","version":"5.2","locale":"ga","docname":"topics/db/examples/one_to_one","url":"/ga/5.2/topics/db/examples/one_to_one/","canonical":"https://djangodocs.dev/ga/5.2/topics/db/examples/one_to_one/","summary":"Chun caidreamh duine le duine a shainiú, bain úsáid as: class: ~Django.db.Models.OneToOneField. Sa sampla seo, is féidir le Áit ``a bheith roghnach ina `Bialann :…","html":"

Caidrimh duine le duineLink to this heading#

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Chun caidreamh duine le duine a shainiú, bain úsáid as: class: ~Django.db.Models.OneToOneField.

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Sa sampla seo, is féidir le Áit ``a bheith roghnach ina `Bialann:

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Code
from django.db import models\n\n\nclass Place(models.Model):\n    name = models.CharField(max_length=50)\n    address = models.CharField(max_length=80)\n\n    def __str__(self):\n        return f"{self.name} the place"\n\n\nclass Restaurant(models.Model):\n    place = models.OneToOneField(\n        Place,\n        on_delete=models.CASCADE,\n        primary_key=True,\n    )\n    serves_hot_dogs = models.BooleanField(default=False)\n    serves_pizza = models.BooleanField(default=False)\n\n    def __str__(self):\n        return "%s the restaurant" % self.place.name\n\n\nclass Waiter(models.Model):\n    restaurant = models.ForeignKey(Restaurant, on_delete=models.CASCADE)\n    name = models.CharField(max_length=50)\n\n    def __str__(self):\n        return "%s the waiter at %s" % (self.name, self.restaurant)\n
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Seo a leanas samplaí d'oibríochtaí is féidir a dhéanamh ag baint úsáide as na háiseanna API Python.

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Cruthaigh cúpla Áiteanna:

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Python console
>>> p1 = Place(name="Demon Dogs", address="944 W. Fullerton")\n>>> p1.save()\n>>> p2 = Place(name="Ace Hardware", address="1013 N. Ashland")\n>>> p2.save()\n
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Cruthaigh Bialann. Pas an réad “tuismitheoir” mar phríomh-eochair an réada seo:

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Python console
>>> r = Restaurant(place=p1, serves_hot_dogs=True, serves_pizza=False)\n>>> r.save()\n
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Is féidir le Bialann rochtain a fháil ar a áit:

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Python console
>>> r.place\n<Place: Demon Dogs the place>\n
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Is féidir le háit rochtain a fháil ar a bhialann, má tá sé ar fáil:

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Python console
>>> p1.restaurant\n<Restaurant: Demon Dogs the restaurant>\n
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níl bialann gaolmhar ag p2:

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Python console
>>> from django.core.exceptions import ObjectDoesNotExist\n>>> try:\n...     p2.restaurant\n... except ObjectDoesNotExist:\n...     print("There is no restaurant here.")\n...\nThere is no restaurant here.\n
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Is féidir leat ``hasattr` a úsáid freisin chun an gá le gabháil eisceachta a sheachaint:

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Python console
>>> hasattr(p2, "restaurant")\nFalse\n
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Socraigh an áit ag baint úsáide as nodaíocht sannta. Toisc gurb é an áit an príomh-eochair ar an mBialann, cruthóidh an sábháil bialann nua:

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Python console
>>> r.place = p2\n>>> r.save()\n>>> p2.restaurant\n<Restaurant: Ace Hardware the restaurant>\n>>> r.place\n<Place: Ace Hardware the place>\n
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Socraigh an áit ar ais arís, ag baint úsáide as sannadh sa treo cúil:

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Python console
>>> p1.restaurant = r\n>>> p1.restaurant\n<Restaurant: Demon Dogs the restaurant>\n
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Tabhair faoi deara go gcaithfidh tú réad a shábháil sula bhféadfar é a shannadh do chaidreamh duine le duine. Mar shampla, ag cruthú Bialain le Plac neamh-shábháilte ardaíonn `Error lua:

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Python console
>>> p3 = Place(name="Demon Dogs", address="944 W. Fullerton")\n>>> Restaurant.objects.create(place=p3, serves_hot_dogs=True, serves_pizza=False)\nTraceback (most recent call last):\n...\nValueError: save() prohibited to prevent data loss due to unsaved related object 'place'.\n
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Tugann Restaurant.objects.all () na Bialanna ar ais, ní na háiteanna. Tabhair faoi deara go bhfuil dhá bhialann ann - Cruthaíodh Ace Hardware an Bialann sa ghlao chuig r.place = p2:

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Python console
>>> Restaurant.objects.all()\n<QuerySet [<Restaurant: Demon Dogs the restaurant>, <Restaurant: Ace Hardware the restaurant>]>\n
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Tugann place.objects.all () gach Áit ar ais, is cuma an bhfuil Bialanna acu:

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Python console
>>> Place.objects.order_by("name")\n<QuerySet [<Place: Ace Hardware the place>, <Place: Demon Dogs the place>]>\n
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<lookups-that-span-relationships>Is féidir leat na samhlacha a cheistiú ag baint úsáidea:ref: `lookups thar fud caidrimh `:

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Python console
>>> Restaurant.objects.get(place=p1)\n<Restaurant: Demon Dogs the restaurant>\n>>> Restaurant.objects.get(place__pk=1)\n<Restaurant: Demon Dogs the restaurant>\n>>> Restaurant.objects.filter(place__name__startswith="Demon")\n<QuerySet [<Restaurant: Demon Dogs the restaurant>]>\n>>> Restaurant.objects.exclude(place__address__contains="Ashland")\n<QuerySet [<Restaurant: Demon Dogs the restaurant>]>\n
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Oibríonn sé seo ar ais freisin:

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Python console
>>> Place.objects.get(pk=1)\n<Place: Demon Dogs the place>\n>>> Place.objects.get(restaurant__place=p1)\n<Place: Demon Dogs the place>\n>>> Place.objects.get(restaurant=r)\n<Place: Demon Dogs the place>\n>>> Place.objects.get(restaurant__place__name__startswith="Demon")\n<Place: Demon Dogs the place>\n
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Má scriosann tú áit, scriosfar a bialann (ag glacadh leis gur sainmhíníodh an OneTooneField` le:attr: ~django.db.models.foreignKey.on_delete socraithe go CASCADE, arb é an réamhshocraithe):

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Python console
>>> p2.delete()\n(2, {'one_to_one.Restaurant': 1, 'one_to_one.Place': 1})\n>>> Restaurant.objects.all()\n<QuerySet [<Restaurant: Demon Dogs the restaurant>]>\n
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Cuir Freastalaí leis an mBialann:

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Python console
>>> w = r.waiter_set.create(name="Joe")\n>>> w\n<Waiter: Joe the waiter at Demon Dogs the restaurant>\n
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Fiosraigh ar na freastálaithe:

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Python console
>>> Waiter.objects.filter(restaurant__place=p1)\n<QuerySet [<Waiter: Joe the waiter at Demon Dogs the restaurant>]>\n>>> Waiter.objects.filter(restaurant__place__name__startswith="Demon")\n<QuerySet [<Waiter: Joe the waiter at Demon Dogs the restaurant>]>\n
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