{"title":"Srianta bunachar sonraí sonracha PostgreSQL","version":"6.1","locale":"ga","docname":"ref/contrib/postgres/constraints","url":"/ga/6.1/ref/contrib/postgres/constraints/","canonical":"https://djangodocs.dev/ga/6.1/ref/contrib/postgres/constraints/","summary":"Tacaíonn PostgreSQL le srianta breise sláine sonraí atá ar fáil ón modúl `` django.contrib.postgres.restricints'. Cuirtear iad…","html":"

Srianta bunachar sonraí sonracha PostgreSQLLink to this heading#

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Tacaíonn PostgreSQL le srianta breise sláine sonraí atá ar fáil ón modúl ``django.contrib.postgres.restricints'. <django.db.models.Options.constraints>Cuirtear iad leis sa rogha samhail: attr: `Meta.Constraints `.

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Srianadh eisiaimLink to this heading#

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\nclass ExclusionConstraint(*, name, expressions, index_type=None, condition=None, deferrable=None, include=None, violation_error_code=None, violation_error_message=None)Link to this definition#
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Cruthaíonn sé srian eisiaimh sa bhunachar sonraí. Go hinmheánach, cuireann PostgreSQL srianta eisiaimh i bhfeidhm ag úsáid innéacsanna. < https://www.postgresql.org/docs/current/gist.html>Is é Gist `_ an cineál innéacs réamhshocraithe. < https://www.postgresql.org/docs/current/btree-gist.html>Chun iad a úsáid, ní mór duit an síneadh `btree_gist `_ a ghníomhachtú ar PostgreSQL. Is féidir leat é a shuiteáil ag baint úsáide as an oibríocht imirce:class: `~django.contrib.postgres.operations.btreegistExtension.

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Má dhéanann tú iarracht sraith nua a chur isteach a dhéanann coinbhleacht leis an tsraith atá ann cheana, ardaítear an:exc: ~django.db.IntegrityError. Ar an gcaoi chéanna, nuair a nuashonraítear coinbhleachtaí le sraith

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<validating-objects>Déantar srianta eisiaimh a sheiceáil le linn an: ref: `bailíochtú samhail `.

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``ainm `Link to this heading#

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\nExclusionConstraint.nameLink to this definition#
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Féach: attr: .baseConstraint.name.

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léiritheachLink to this heading#

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\nExclusionConstraint.expressionsLink to this definition#
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Athraitheach de 2-tuples. Is é an chéad eilimint ná abairt nó sreang. Is é an dara gné ná oibreoir SQL a léirítear mar shreang. Chun clóscríobh a sheachaint, is féidir leat: class: ~django.contrib.postgres.fields.rangeOperators a mhéapálann na hoibreoirí le teaghráin. Mar shampla:

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expressions = [\n    ("timespan", RangeOperators.ADJACENT_TO),\n    (F("room"), RangeOperators.EQUAL),\n]\n
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Is féidir an abairt: class: `op <django.contrib.postgres.indexes.OpClass>Class () `a úsáid chun `aicme oibreora `_ saincheaptha a shonrú do na nathanna srianta. Mar shampla:

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expressions = [\n    (OpClass("circle", name="circle_ops"), RangeOperators.OVERLAPS),\n]\n
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cruthaíonn srian eisiaimh ar circle ag baint úsáide as circle_ops.

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cineál_innéacsaLink to this heading#

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\nExclusionConstraint.index_typeLink to this definition#
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The index type of the constraint. Accepted values are GiST, Hash, or\nSPGiST. Matching is case insensitive. If not provided, the default index\ntype is GIST.

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coinníollLink to this heading#

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\nExclusionConstraint.conditionLink to this definition#
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A: Aicme: ~Django.db.Models.q réad a shonraíonn an coinníoll chun srian a shrianadh le fo-thacar sraitheanna. Mar shampla, ``Condition=Q (cealaithe = bréagach) ``.

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Tá na srianta bunachar sonraí céanna ag na coinníollacha seo las:attr: django.db.models.index.condition.

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iarchurraitheLink to this heading#

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\nExclusionConstraint.deferrableLink to this definition#
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Socraigh an paraiméadar seo chun srian eisiaimh in-iarchurtha a chruthú. Is iad na luachanna a nglactar leo ná Deferrable.Ferred nó Deferrable.Immediate. Mar shampla:

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from django.contrib.postgres.constraints import ExclusionConstraint\nfrom django.contrib.postgres.fields import RangeOperators\nfrom django.db.models import Deferrable\n\nExclusionConstraint(\n    name="exclude_overlapping_deferred",\n    expressions=[\n        ("timespan", RangeOperators.OVERLAPS),\n    ],\n    deferrable=Deferrable.DEFERRED,\n)\n
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De réir réamhshocraithe ní chuirtear srianta ar iarchur. Ní chuirfear srian iarchurtha i bhfeidhm go dtí deireadh an idirbheart. Cuirfear srian láithreach i bhfeidhm díreach tar éis gach ordaithe.

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``san áireamh ``Link to this heading#

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\nExclusionConstraint.includeLink to this definition#
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Liosta nó tuipéar d'ainmneacha na réimsí atá le cur san áireamh sa srian eisiaimh clúdaigh mar cholúin neamh-lárnacha. Ligeann sé seo scananna innéacs amháin a úsáid le haghaidh ceisteanna nach roghnaíonn ach réimsí san áireamh (:attr: ~ExclusionConstraint.include) agus ní scagann ach amháin de réir réimsí innéacsaithe (:attr: ~ExclusionConstraint.Expressions).

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include is supported for GiST and SP-GiST indexes.

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``cód_earráid_shárú `Link to this heading#

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\nExclusionConstraint.violation_error_codeLink to this definition#
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<validating-objects>An cód earráide a úsáidtear nuair a ardaítear ValidationError trí:ref: bailíochtú samhail `. Réamhshocraithe go ``None`.

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``teachtaireachtaí earráid_shárúcháin ``Link to this heading#

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<validating-objects>An teachtaireacht earráide a úsáidtear nuair a ardaítear ValidationError trí:ref: bailíochtú samhail `. Réamhshocraithe to:attr: `.baseConstraint.VIOLATION_ERROR_MESSAGE.

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SamplaíLink to this heading#

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Cuireann an sampla seo a leanas srian ar áirithintí forluí sa seomra céanna, gan áirithintí cealaithe a chur san áireamh:

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from django.contrib.postgres.constraints import ExclusionConstraint\nfrom django.contrib.postgres.fields import DateTimeRangeField, RangeOperators\nfrom django.db import models\nfrom django.db.models import Q\n\n\nclass Room(models.Model):\n    number = models.IntegerField()\n\n\nclass Reservation(models.Model):\n    room = models.ForeignKey("Room", on_delete=models.CASCADE)\n    timespan = DateTimeRangeField()\n    cancelled = models.BooleanField(default=False)\n\n    class Meta:\n        constraints = [\n            ExclusionConstraint(\n                name="exclude_overlapping_reservations",\n                expressions=[\n                    ("timespan", RangeOperators.OVERLAPS),\n                    ("room", RangeOperators.EQUAL),\n                ],\n                condition=Q(cancelled=False),\n            ),\n        ]\n
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Sa chás go sainmhíníonn do mhúnla raon ag baint úsáide as dhá réimse, in ionad na cineálacha raon dúchasacha PostgreSQL, ba cheart duit abairt a scríobh a úsáideann an fheidhm choibhéiseach (m.sh. TstzRange () `), agus na teorannaithe a úsáid don réimse. Is minic a bheidh na teorannaitheoirí ná ``'[) ', rud a chiallaíonn go bhfuil an teorainn íochtarach cuimsitheach agus go bhfuil an teorainn uachtarach eisiach. < https://www.postgresql.org/docs/ current/rangetypes.html #RANGETYPES -INCLUSIVITY>Is féidir leat an: class: ~django.contrib.postgres.fields.rangeBoundary a sholáthraíonn léarscáil abairt do na `teorainneacha raon `_ a úsáid. Mar shampla:

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from django.contrib.postgres.constraints import ExclusionConstraint\nfrom django.contrib.postgres.fields import (\n    DateTimeRangeField,\n    RangeBoundary,\n    RangeOperators,\n)\nfrom django.db import models\nfrom django.db.models import Func, Q\n\n\nclass TsTzRange(Func):\n    function = "TSTZRANGE"\n    output_field = DateTimeRangeField()\n\n\nclass Reservation(models.Model):\n    room = models.ForeignKey("Room", on_delete=models.CASCADE)\n    start = models.DateTimeField()\n    end = models.DateTimeField()\n    cancelled = models.BooleanField(default=False)\n\n    class Meta:\n        constraints = [\n            ExclusionConstraint(\n                name="exclude_overlapping_reservations",\n                expressions=[\n                    (\n                        TsTzRange("start", "end", RangeBoundary()),\n                        RangeOperators.OVERLAPS,\n                    ),\n                    ("room", RangeOperators.EQUAL),\n                ],\n                condition=Q(cancelled=False),\n            ),\n        ]\n
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