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c# - 无法在 Scaffold-DbContext .Net Core 中将“System.DBNull”类型的对象转换为“System.String”类型

我使用以下方法来使用数据库：

但在某些数据库中，我收到此错误：

无法将“System.DBNull”类型的对象转换为“System.String”类型

此错误发生在Scaffold-DbContext命令写入包管理器控制台后，我按下Enter并没有对任何表进行分类。

我能做些什么来解决这个错误？

在此处输入图像描述

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c# - How can I Update-Database?

this is the code used to generate the migration

dotnet ef migrations add InitialCreate --context DataContext --output-dir Migrations/SqlServerMigrations and this is the DataContext.cs

but when I run Upadate-Database I get the error "More than one DbContext was found. Specify which one to use. Use the '-Context' parameter for PowerShell commands and the '--context' parameter for dotnet commands."

How can I update the database using this migration?


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