{"title":"Tagairt srianta","version":"6.0","locale":"ga","docname":"ref/models/constraints","url":"/ga/6.0/ref/models/constraints/","canonical":"https://djangodocs.dev/ga/6.0/ref/models/constraints/","summary":"Cruthaíonn na ranganna atá sainithe sa mhodúl seo srianta bunachar sonraí. Cuirtear iad leis sa rogha samhail: attr…","html":"

Tagairt sriantaLink to this heading#

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Cruthaíonn na ranganna atá sainithe sa mhodúl seo srianta bunachar sonraí. <django.db.models.Options.constraints>Cuirtear iad leis sa rogha samhail: attr: `Meta.Constraints `.

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BaseConstraintLink to this heading#

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\nclass BaseConstraint(*name, violation_error_code=None, violation_error_message=None)Link to this definition#
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Aicme bonn do gach srianta. Ní mór do fho-aicmí modhanna restricint_sql () ``, `create_sql (), remove_sql () ``agus ``validate ()` a chur i bhfeidhm.

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Tá na paraiméadair seo a leanas i gcoiteann ag gach srianta:

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``ainm `Link to this heading#

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\nBaseConstraint.nameLink to this definition#
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Ainm an srianta. Ní mór duit ainm uathúil a shonrú i gcónaí don srian.

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``cód_earráid_shárú `Link to this heading#

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\nBaseConstraint.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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\nBaseConstraint.violation_error_messageLink to this definition#
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<validating-objects>An teachtaireacht earráide a úsáidtear nuair a ardaítear ValidationError trí:ref: bailíochtú samhail `. Sárófar réamhshocraithe go `"Scrianadh “% (name) s”.

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``bailíochtú () ``Link to this heading#

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\nBaseConstraint.validate(model, instance, exclude=None, using=DEFAULT_DB_ALIAS)Link to this definition#
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Bailíonn sé go n-urramaítear an srian, a shainmhínítear ar samhail `, ar an instance`. Déanfaidh sé seo ceist ar an mbunachar sonraí chun a chinntiú go n-urramaítear an srian. Má theastaíonn réimsí sa liosta eisiam chun an srian a bhailíochtú, déantar neamhaird ar an srian.

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Ardaigh Error Validation má sháraítear an srian.

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Caithfidh fo-aicme an modh seo a chur i bhfeidhm.

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Srianadh seiceálaLink to this heading#

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\nclass CheckConstraint(*, condition, name, violation_error_code=None, violation_error_message=None)Link to this definition#
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Cruthaíonn sé srian seiceála sa bhunachar sonraí.

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coinníollLink to this heading#

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\nCheckConstraint.conditionLink to this definition#
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A: aicme: Q réad nó boolean:class: ~django.db.Models.Expression a shonraíonn an seiceáil choinníollach a theastaíonn uait an srian a fhorfheidhmiú.

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Mar shampla:

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CheckConstraint(condition=Q(age__gte=18), name="age_gte_18")\n
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ensures the age field is never less than 18.

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UniqueConstraintLink to this heading#

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\nclass UniqueConstraint(*expressions, fields=(), name=None, condition=None, deferrable=None, include=None, opclasses=(), nulls_distinct=None, violation_error_code=None, violation_error_message=None)Link to this definition#
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Creates a uniqueness guarantee in the database, enforced by either a\nunique constraint or a unique index depending on the options used.

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léiritheachLink to this heading#

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\nUniqueConstraint.expressionsLink to this definition#
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Ligeann argóint seasaimh ``* léirithe ``srianta feidhmiúla uathúla a chruthú ar nathanna agus ar fheidhmeanna bunachar sonraí.

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Mar shampla:

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UniqueConstraint(Lower("name").desc(), "category", name="unique_lower_name_category")\n
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cruthaíonn sé srian uathúil ar luach íseal an réimse ``ainm ``in ord íslitheach agus an réimse catagóir san ord ardaitheach réamhshocraithe.

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Tá na srianta bunachar sonraí céanna ag srianta uathúla feidhmiúla las:attr: Index.Expressions.

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``réimsí ``Link to this heading#

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\nUniqueConstraint.fieldsLink to this definition#
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Liosta d'ainmneacha réimse a shonraíonn an tacar uathúil colún a theastaíonn uait an srian a fhorfheidhmiú.

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Mar shampla:

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UniqueConstraint(fields=["room", "date"], name="unique_booking")\n
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ensures each room can only be booked once for each date.

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coinníollLink to this heading#

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\nUniqueConstraint.conditionLink to this definition#
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A: aicme: 'Q` réad a shonraíonn an coinníoll a theastaíonn uait an srian a fhorfheidhmiú.

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Mar shampla:

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UniqueConstraint(fields=["user"], condition=Q(status="DRAFT"), name="unique_draft_user")\n
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cinntíonn sé nach bhfuil ach dréacht amháin ag gach úsáideoir.

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Tá na srianta bunachar sonraí céanna ag na coinníollacha seo las:attr: Index.Condition.

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iarchurraitheLink to this heading#

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\nUniqueConstraint.deferrableLink to this definition#
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Socraigh an paraiméadar seo chun srian uathúil 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.db.models import Deferrable, UniqueConstraint\n\nUniqueConstraint(\n    name="unique_order",\n    fields=["order"],\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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Unique constraints with condition,\ninclude, opclasses, or\nexpressions may be implemented as unique indexes\nrather than unique constraints. In that case, deferrable cannot be set.

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``san áireamh ``Link to this heading#

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\nUniqueConstraint.includeLink to this definition#
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Liosta nó tuple d'ainmneacha na réimsí atá le cur san innéacs uathúil clúdaigh mar cholúin neamh-eochair. Ligeann sé seo scananna innéacs amháin a úsáid le haghaidh ceisteanna nach roghnaíonn ach réimsí san áireamh (:attr: ~UniqueConstraint.include) agus scagadh ach amháin de réir réimsí uathúla (:attr: ~UniqueConstraint.fields).

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Mar shampla:

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UniqueConstraint(name="unique_booking", fields=["room", "date"], include=["full_name"])\n
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ceadóidh sé scagadh ar seomra agus dáta, ag roghnú full_name freisin, agus sonraí a thógáil ach ón innéacs.

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Déantar neamhaird ar srianta uathúla le colúin neamh-eochair do bhunachair sonraí seachas PostgreSQL.

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Tá na srianta bunachar sonraí céanna ag colúin neamh-eochair las:attr: Index.include.

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opclassesLink to this heading#

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\nUniqueConstraint.opclassesLink to this definition#
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< https://www.postgresql.org/docs/current/indexes-opclass.html>Ainmneacha na `ranganna oibreora PostgreSQL `_ le húsáid don innéacs uathúil seo. Má theastaíonn rang oibreora saincheaptha uait, ní mór duit ceann a sholáthar do gach réimse san innéacs.

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Mar shampla:

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UniqueConstraint(\n    name="unique_username", fields=["username"], opclasses=["varchar_pattern_ops"]\n)\n
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cruthaíonn innéacs uathúil ar ainm úsáideora ``ag baint úsáide as ``varchar_pattern_ops.

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Déantar neamhaird ar opclasses le haghaidh bunachair sonraí seachas PostgreSQL.

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nulls_distintLink to this heading#

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\nUniqueConstraint.nulls_distinctLink to this definition#
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Ba chóir sraitheanna ina bhfuil luachanna NULL` atá clúdaithe leis an srian uathúil a mheas ar leith óna chéile. Is é an luach réamhshocraithe None a úsáideann réamhshocraithe an bunachar sonraí atá True ar fhormhór na gcúltaca.

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Mar shampla:

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UniqueConstraint(name="ordering", fields=["ordering"], nulls_distinct=False)\n
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cruthaíonn srian uathúil nach gceadaíonn ach sraith amháin luach NULL a stóráil sa cholún ``ordú ``.

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Déantar neamhaird ar srianta uathúla le nulls_distingt` do bhunachair sonraí seachas PostgreSQL 15+.

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``cód_earráid_shárú `Link to this heading#

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\nUniqueConstraint.violation_error_codeLink to this definition#
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The error code used when a ValidationError is raised during\nmodel validation.

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Defaults to BaseConstraint.violation_error_code, when either\nUniqueConstraint.condition is set or UniqueConstraint.fields\nis not set.

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If UniqueConstraint.fields is set without a\nUniqueConstraint.condition, defaults to the\nMeta.unique_together error\ncode when there are multiple fields, and to the Field.unique error\ncode when there is a single field.

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``teachtaireachtaí earráid_shárúcháin ``Link to this heading#

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\nUniqueConstraint.violation_error_messageLink to this definition#
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The error message used when a ValidationError is raised during\nmodel validation.

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Defaults to BaseConstraint.violation_error_message, when either\nUniqueConstraint.condition is set or UniqueConstraint.fields\nis not set.

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If UniqueConstraint.fields is set without a\nUniqueConstraint.condition, defaults to the\nMeta.unique_together error\nmessage when there are multiple fields, and to the Field.unique error\nmessage when there is a single field.

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