Question

将MySQL与Django一起使用，我已经将模型从使用“category”的字符串更改为使用FK。它现在被

打破了

django.db.utils.OperationalError: (1366, "Incorrect integer value: 'Category object' for column 'category_id' at row 1")

最初看起来像：

class ItemRecord(models.Model):
    catalog_id = models.IntegerField()
    name = models.CharField(max_length=250)
    price = models.DecimalField(max_digits=7, decimal_places=2)
    active = models.BooleanField(default=True) # is the item being sold at all? (carried)
    in_stock = models.BooleanField(default=True) # is the item currently in stock?
    banned = models.BooleanField(default=False)
    category = models.CharField(max_length=250, null=True, blank=True)

    class Meta:
        abstract = True


class FermentableRecord(ItemRecord):#record of each item
    pass

class HopRecord(ItemRecord):
    pass

class YeastRecord(ItemRecord):
    pass

然后，我使用FK：

class Category(models.Model):
    name = models.CharField(max_length=250)
    banned = models.BooleanField(default=False)


class ItemRecord(models.Model):
    catalog_id = models.IntegerField()
    name = models.CharField(max_length=250)
    price = models.DecimalField(max_digits=7, decimal_places=2)
    active = models.BooleanField(default=True) # is the item being sold at all? (carried)
    in_stock = models.BooleanField(default=True) # is the item currently in stock?
    banned = models.BooleanField(default=False)
    category = models.ForeignKey(Category, related_name="items")

    class Meta:
        abstract = True


class FermentableRecord(ItemRecord):#record of each item
    pass

class HopRecord(ItemRecord):
    pass

class YeastRecord(ItemRecord):
    pass

这在3种不同的Record型号上使用相同的相关名称。接下来我有：

class Category(models.Model):
    name = models.CharField(max_length=250)
    banned = models.BooleanField(default=False)


class ItemRecord(models.Model):
    catalog_id = models.IntegerField()
    name = models.CharField(max_length=250)
    price = models.DecimalField(max_digits=7, decimal_places=2)
    active = models.BooleanField(default=True) # is the item being sold at all? (carried)
    in_stock = models.BooleanField(default=True) # is the item currently in stock?
    banned = models.BooleanField(default=False)

    class Meta:
        abstract = True


class FermentableRecord(ItemRecord):#record of each item
    category = models.ForeignKey(Category, related_name="fermentable_items", null=True, blank=True)

class HopRecord(ItemRecord):
    category = models.ForeignKey(Category, related_name="hops_items", null=True, blank=True)

class YeastRecord(ItemRecord):
    category = models.ForeignKey(Category, related_name="yeast_items", null=True, blank=True)

现在我有：

class Category(models.Model):
    name = models.CharField(max_length=250)
    banned = models.BooleanField(default=False)


class ItemRecord(models.Model):
    catalog_id = models.IntegerField()
    name = models.CharField(max_length=250)
    price = models.DecimalField(max_digits=7, decimal_places=2)
    active = models.BooleanField(default=True) # is the item being sold at all? (carried)
    in_stock = models.BooleanField(default=True) # is the item currently in stock?
    banned = models.BooleanField(default=False)
    category = models.CharField(max_length=250, null=True, blank=True)

    class Meta:
        abstract = True


class FermentableRecord(ItemRecord):#record of each item
    pass

class HopRecord(ItemRecord):
    pass

class YeastRecord(ItemRecord):
    pass

我可以makemigrations，但我根本无法连接到db。我想重置数据库，因为它正处于开发阶段，但我什么也做不了。 category字段是一个字符串，然后我将它设置为FK，它在清除现有字符串值之前需要一个int（由于错误，所有'Category对象'都在这里）。

Answer 1

如果您只想删除类别中的数据，则可以在shell中执行以下操作：

$ python manage.py dbshell # this will start the mysql client
mysql> show tables likes '%_itemrecord'; -- find the table name
mysql> update XXX_itemrecord set category=null; -- this will set all category values to NULL so that you can migrate to FK

如果您不介意丢失数据，并且您的应用程序名称是app_name，则可以在shell中执行以下操作：

$ python manage.py migrate app_name zero # this will blow away all your current data
$ python manage.py migrate app_name

Answer 2

您是否检查类别表中是否存在类别对象，其中ID最初存储在类别字段中。

例如：对于id = 1366

，存在类别对象

Category.objects.filter(id=1366).exists()

MySQL：django.db.utils.OperationalError：（1366，“不正确的整数值：'第1行'列'category_id'的'类别对象'”）

2 个答案: