Question

如何在CREATE TABLE结束时添加DEFAULT CONSTRAINT？

我想在最后有一个独立的行，如

class User(AbstractBaseUser, PermissionsMixin):
    email = models.EmailField(
        verbose_name=_('Email'), max_length=255, unique=True
    )
    first_name = models.CharField(verbose_name=_('First Name'), 
        max_length=50)
    last_name = models.CharField(verbose_name=_('Last Name'), 
        max_length=50)
    is_active = models.BooleanField(verbose_name=_('Active'), 
        default=True)
    is_staff = models.BooleanField(verbose_name=_('Staff'), 
        default=False)
    is_verify = models.BooleanField(verbose_name=_('Verify'), 
        default=False)

    objects = UserManager()

    USERNAME_FIELD = 'email'
    REQUIRED_FIELDS = ['first_name', 'last_name']

    class Meta:
        verbose_name = _('User')
        verbose_name_plural = _('Users')

    def __str__(self):
        return self.get_full_name()

    def get_full_name(self):
        return '{first_name} {last_name}'.format(
            first_name=self.first_name, last_name=self.last_name
        )

    def get_short_name(self):
        return '{first_name}'.format(first_name=self.first_name)


def activation_key():
    while True :
        key = (''.join(choice(hexdigits) for i in range(50)))
        if ActivationKey.objects.filter(key=key).count() == 0:
        return key

class ActivationKey(models.Model):
    user = models.ForeignKey(verbose_name=_('User'), to='users.User',
                         related_name='activatio_with_mail')
    is_used = models.BooleanField(verbose_name=_('Used'), 
             default=False)
    key = models.CharField(verbose_name=_('Key'), max_length=50,
                       unique=True)

    class Meta:
        verbose_name = _('ActivationKey')
        verbose_name_plural = _('ActivationKey')

    def __str__(self):
       return self.key

    def save(self, *args, **kwargs):
       if not self.pk:
            self.key = activation_key()
            super(ActivationKey, self).save(*args, **kwargs)

它无法正常工作。我收到错误消息

＆＃39;附近的语法不正确。

你可以帮帮我吗？非常感谢前进！

Answer 1

您应该只使用默认值旁边的默认值，例如：

CREATE TABLE myTable (
  table_id       INT NOT NULL,
  firstColumn    NVARCHAR(10),
  secondColumn   INT DEFAULT 0,
  thirdColumn    INT
)

或者，如果您确实要添加约束，可以稍后使用ALTER TABLE添加约束：

CREATE TABLE myTable (
  table_id       INT NOT NULL,
  firstColumn    NVARCHAR(10),
  secondColumn   INT,
  thirdColumn    INT
)

ALTER TABLE myTable ADD CONSTRAINT DEF_secColumn DEFAULT 0 FOR [secondColumn]

或@ jeroen-mostert建议的第三个选项

CREATE TABLE myTable (
  table_id       INT NOT NULL,
  firstColumn    NVARCHAR(10),
  secondColumn   INT CONSTRAINT DEF_secColumn DEFAULT 0,
  thirdColumn    INT
)

在CREATE TABLE的末尾添加DEFAULT CONSTRAINT

1 个答案: