UniqueConstraint(fields=["user"],condition=Q(status="DRAFT"),name="unique_draft_user") 确保每个用户只有一份草稿。 这些条件与Index.condition具有相同的数据库限制。 deferrable¶ UniqueConstraint.deferrable¶ 设置该参数,可创建一个可推迟的唯一约束。接受的值是Deferrable.DEFERRED或Deferrable.IMMEDIATE。例...
Note that in the demo project I also added a secondUniqueConstraintwith three fields and no condition, and that works like a charm (test cases there to prove). That second constraint actually show the pattern that I use in the main project, which is to have an unique constraint on three...
models.UniqueConstraint( fields=['question','correct'],name='single_unique_correct', condition=Q(ques_type='true_false')) ] 有一个缺陷是:不能用关联表的字段作为约束条件,不能用双下划线跨表,若有此需求,考虑把相关字段写到本类中(费事,但没办法)。 功能更强大的UniqueConstraint用于全面代替unique_tog...
UniqueConstraint in django 2.2不引发ValidationError 、、 因为django 2.2 建议使用UniqueConstraint而不是unique_together,但是如果提供condition属性,这个选项不会在django管理中引发ValidationErrorUniqueConstraint是否有可能在不自行实现验证逻辑的情况下提高ValidationError(在django管理中)而不是IntegrityError? 浏览0提问于2019...
class Meta: verbose_name = _("Idea") verbose_name_plural = _("Ideas") constraints = [ models.UniqueConstraint( fields=["title"], condition=~models.Q(author=None), name="unique_titles_for_each_author2", ), models.CheckConstraint( check=models.Q( title__iregex=r"^\S.*\S$" # ...
在一个模型中，我需要使用两个UniqueConstraint实例。
(symbol=json_obj['order_id'], amount= json_obj['amnount']) try: order.save() except IntegrityError as exception: if 'UNIQUE constraint failed' in exception.args[0]: print('duplicate order id => skip this') continue一切正常,但是当我将 @transaction.atomic 装饰器添加到我的函数时,一切...
For example, if age is a nullable field: CheckConstraint(condition=Q(age__gte=18) | Q(age__isnull=True), name="age_gte_18") UniqueConstraint¶ class UniqueConstraint(*expressions, fields=(), name=None, condition=None, deferrable=None, include=None, opclasses=(), nulls_distinct=None,...
[ models.UniqueConstraint( fields=["name"], name="mymodel_unique_name_measure_null", condition=Q(measure__isnull=True), violation_error_message="Error message for null", ), models.UniqueConstraint( fields=["name", "measure"], name="mymodel_unique_name_measure_not_null", condition=Q(...
新特性约束新的CheckConstraint和UniqueConstraint类现在开始支持自定义数据库约束，通过使用Meta.constraints选项。小特性1. django.contrib.admin为TabularInline添加了列头的CSS类2. django.contrib.authHttpRequest将被作为第一个位置参数传递给RemoteUserBackend.configure_user()方法。3. django.contrib.gisEnvelope函数开始...