valueError: int() 的无效文字，基数为 10: '' while migrate

Question

我在 django-2 中编写了这个简单的模型，当我尝试迁移时，我得到了

ValueError: int() 以 10 为底的无效文字：''

from django.db import models

class Teacher(models.Model):
    name = models.CharField(max_length=50)
    user = models.IntegerField(default='',blank=True)
    passcode = models.IntegerField(default='',blank=True)

    def __str__(self):
        return self.name


class Student(models.Model):
    name = models.CharField(max_length=50)
    user = models.IntegerField(default='', blank=True)
    passcode = models.IntegerField(default='', blank=True)
    teacher = models.ManyToManyField(Teacher)   

    def __str__(self):
        return self.name

class Lesson (models.Model):
    name = models.CharField(max_length=50)
    cource = models.IntegerField(default='', blank=True)
    teacher = models.ForeignKey("Teacher", on_delete=models.CASCADE)
    Student = models.ManyToManyField(Student)

    def __str__(self):
        return self.name

class Score(models.Model):
    score = models.FloatField(default='', blank=True)
    student = models.ForeignKey(Student, on_delete=models.CASCADE)
    lesson = models.ForeignKey(Lesson, on_delete=models.CASCADE)

Answer 1

IntegerField 和 FloatField 的默认值不能是字符串。

default='' 表示一个空字符串。

将IntegerField 和FloatField 的默认值更改为某个数字或设置null=True：

示例：

# Means it can not be empty and if it received empty, put 0 instead.
score = models.FloatField(default=0, blank=True)

或者

# Means it is okay to be empty.
score = models.FloatField(null=True, blank=True)

此外，您可能需要删除以前更改的迁移文件。