实体框架核心项目的迁移失败，并且调试配置文件不存在 [英] Entity Framework Core project's migration fails and debug profile does not exist

问题描述

我尝试创建 Entity Framework Core 迁移，但是失败.这是Visual Studio 2019程序包管理器控制台的输出

I tried to create an Entity Framework Core migration but it fails. This is the output from the Visual Studio 2019 Package manager console

> Each package is licensed to you by its owner. NuGet is not responsible for, nor does it grant any licenses to, third-party packages. Some packages may include dependencies that are governed by additional licenses. Follow the package source (feed) URL to determine any dependencies.
>
> Package Manager Console Host Version 5.7.0.6726
>
> Type 'get-help NuGet' to see all available NuGet commands.

PM> Add-Migration InitialCreate

> Build started...  
> Build failed.  

然后我尝试构建我的代码，并遇到以下问题:调试配置文件不存在.我该如何解决这个问题?我已经尝试了一切，但似乎无法解决.

I then tried to build my code and got the following problem: debug profile does not exist. How do I fix this problem? I have tried everything and I just can't seem to solve it.

推荐答案

根据您的描述，您想要创建一个Entity Framework Core迁移.

Based on your description, you want to create an Entity Framework Core migration.

我假设您使用的是sqlserver.

I assumed that you use sqlserver.

您可以参考以下步骤来创建EF Core迁移.

You can refer to the following steps to create the EF Core migration.

首先，请创建一个控制台应用程序(.Net Core).

First, please create an console app(.Net Core).

第二，请安装以下nuget软件包:

Second,please install the following nuget packages:

• Microsoft.EntityFrameworkCore.SqlServer
• Microsoft.EntityFrameworkCore.Design
• Microsoft.EntityFrameworkCore.Tools

第三，请向您的控制台应用程序添加两个类.

Third, please add two classes to your console app.

public class Teacher
{
    public int TeaID { get; set; }
    public int Age { get; set; }
    public string Name { get; set; }
}

public class TeaContext : DbContext
{
    public DbSet<Teacher> Teachers { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
            .UseSqlServer(@"Connectionstring");
    }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Teacher>()
            .HasNoKey();
    }
}

Connectionstring是您连接到sql server数据库的字符串.(请首先创建一个数据库)第三，您可以在程序包管理器"控制台中执行以下命令.

The Connectionstring is the string that you connect to sql server database.(please create a database first) Third, you can execute the following command in the Package manager console.

PM> Add-Migration Initial

PM> Update-Database

最后，您可以检查数据库设计.

Finally, you can check the database design.

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