环境：
.NET5.0
VS2019 社区版
创建以简单的控制台应用。使用Code Frist,
功能简单的一对多的数据更新。
Database operation expected to affect 1 row(s) but actually affected 0 row(s).
Data may have been modified or deleted since entities were loaded.
See http://go.microsoft.com/fwlink/?LinkId=527962 for information on understanding and handling optimistic concurrency exceptions.
遇到这个问题在网上一搜全是关于并发的问题。搞得很严重似的，如图：报错代码