帶有DateField的Django IntegrityError-使用get_or_create創建對象時

Question

每當我創建具有相同日期的相同對象時，都會彈出Django的get_or_create問題，出現完整性錯誤。

我的模型中有以下字段。

class Cart(models.Model):
    created = models.DateTimeField(
        pgettext_lazy('Cart field', 'created'), auto_now_add=True)
    last_status_change = models.DateTimeField(
        pgettext_lazy('Cart field', 'last status change'), auto_now_add=True)
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL, blank=True, null=True, related_name='carts',
        verbose_name=pgettext_lazy('Cart field', 'user'))
    email = models.EmailField(
        pgettext_lazy('Cart field', 'email'), blank=True, null=True)

    def add(self,hoarding, date_from, date_until):
        cart_line, created = self.lines.get_or_create(
            hoarding=hoarding,date_from=date_from,date_until=date_until)



class Meta:
        ordering = ('-last_status_change',)
        verbose_name = pgettext_lazy('Cart model', 'Cart')
        verbose_name_plural = pgettext_lazy('Cart model', 'Carts')

    def __str__(self):
        return smart_str(self.user)


class CartLine(models.Model):
    cart = models.ForeignKey(
        Cart, related_name='lines',
        verbose_name=pgettext_lazy('Cart line field', 'cart'))

    hoarding = models.ForeignKey(
        Hoarding, related_name='+',blank=True, null=True,
        verbose_name=pgettext_lazy('Cart line field', 'hoarding'))

    date_from = models.DateField(blank=True, null=True,
        verbose_name=pgettext_lazy('Cart line field', 'from'))

    date_until = models.DateField(blank=True, null=True,
        verbose_name=pgettext_lazy('Cart line field', 'until'))

    class Meta:
        unique_together = ('cart', 'date_from', 'date_until')
        verbose_name = pgettext_lazy('Cart line model', 'Cart line')
        verbose_name_plural = pgettext_lazy('Cart line model', 'Cart lines')

當我嘗試使用相同的起始日期和直到日期將相同的對象添加到購物車時，會出現錯誤：

IntegrityError at /hoardings/hoardings-demo-2-5/add/
UNIQUE constraint failed: cart_cartline.cart_id, cart_cartline.date_from, cart_cartline.date_until

創建具有相同日期的對象時， get_or_create將返回IntegrityError。我在datefield中添加了獨特功能，但遇到了相同的錯誤。 我使用Django 1.11和Python 2.7

我幾次重設數據庫，但沒有幫助，db是Postgres / sqlite。

Answer 1

unique_together模型中的unique_together引起完整性問題。刪除該行，然后遷移。

class CartLine(models.Model):
    cart = models.ForeignKey(
        Cart, related_name='lines',
        verbose_name=pgettext_lazy('Cart line field', 'cart'))

    hoarding = models.ForeignKey(
        Hoarding, related_name='+',blank=True, null=True,
        verbose_name=pgettext_lazy('Cart line field', 'hoarding'))

    date_from = models.DateField(blank=True, null=True,
        verbose_name=pgettext_lazy('Cart line field', 'from'))

    date_until = models.DateField(blank=True, null=True,
        verbose_name=pgettext_lazy('Cart line field', 'until'))

    class Meta:
        verbose_name = pgettext_lazy('Cart line model', 'Cart line')
        verbose_name_plural = pgettext_lazy('Cart line model', 'Cart lines')