Django:保存模型时检测一组字段的更改

from django.db import models

class MyModel(models.Model):
    field1 = models.CharField(max_length=100)
    field2 = models.IntegerField()
    previous_state = models.JSONField(default=dict)  # 存储先前状态的字段

from django.db import models

class MyModel(models.Model):
    field1 = models.CharField(max_length=100)
    field2 = models.IntegerField()
    previous_state = models.JSONField(default=dict)

    def save(self, *args, **kwargs):
        if self.pk:  # 如果模型已存在（即已保存过）
            previous_state = MyModel.objects.get(pk=self.pk)  # 获取先前状态
            if self.field1 != previous_state.field1:
                # field1 发生了更改
                # 执行相应的操作
            if self.field2 != previous_state.field2:
                # field2 发生了更改
                # 执行相应的操作
        super().save(*args, **kwargs)  # 保存模型