DjangoModels修改后出现You are trying to add a non-nullable field 'download' to book without a default; we can't do that (the database needs something to populate existing rows). Please select a fix: - 码上欢乐

相关内容简体繁体

DjangoModels修改后出现You are trying to add a non-nullable field 'download' to book without a default; we can't do that (the database needs something to populate existing rows). Please select a fix:

本文转载自查看原文 2020-07-09 08:50 1915 Django

这个问题是在模型中新添加的，在原来已经有的表单中没有值。所以在新添加的值得括号中添加

如

  1 download = models.ForeignKey(Download, on_delete=models.CASCADE, null=True)

然后

  1 python manage.py makemigrations
  2 
  3 python manage.py migrate

免责声明！

本站转载的文章为个人学习借鉴使用，本站对版权不负任何法律责任。如果侵犯了您的隐私权益，请联系本站邮箱yoyou2525@163.com删除。

猜您在找 the database needs something to populate existing rows. Django | 模型类变更后生成迁移文件，报错:You are trying to add a non-nullable field 'BookName' to BookInfo without a default.... python manage.py makemigrat Please select a fix: 1) Provide a one-off default now (will be set on all existing rows with a null value for this column) 2) Quit, and let me add a default in models.py EXCEL : We can't do that to a merged cell. MHA 报错：There is no alive slave. We can't do failover unity can't add the script behaviour CallbackExecutor. The script needs ... mongodb you can't add a second Vue部署到云服务器时，访问Nginx代理出现We're sorry but books doesn't work properly without JavaScript enabled. Please enable it to continue. Can‘t download sh shfmt formatter. Please install it manually We're sorry but mobile doesn't work properly without JavaScript enabled. Please enable it to continue.

粤ICP备18138465号 © 2018-2025 CODEPRJ.COM