“每个表中的列名必须是唯一的。”在数据库更新期间 [英] "Column names in each table must be unique." during database update

问题描述

我对ASP.NET完全陌生，但这是我的第一个带有ASP.NET Core的应用程序。创建迁移后，我在更新数据库时遇到问题。当我键入命令： dotnet ef数据库更新时，出现错误：

I am quite new to ASP.NET at all, however this is my first app with ASP.NET Core. I have problem with updating database after creating the migration. While I type command: dotnet ef database update, I get error:

Column每个表中的名称必须唯一。表 Adverts中的列名 PortalUserId
被多次指定。

Column names in each table must be unique. Column name 'PortalUserId' in table 'Adverts' is specified more than once.

我认为问题出在我的模型结构，但我不知道我在做什么错。当我使用ASP.NET MVC 5进行开发时，一切都很好。

I think the problem is with my model structure, but I do not know what I am doing wrong. When I was developing with ASP.NET MVC 5 everything was Ok.

这里是我的模型（对于案例实体来说是不必要的）：

Here is my Model (without unnecessary for the case entities):

public class ApplicationDbContext : IdentityDbContext
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }
    public DbSet<PortalUser> PortalUsers { get; set; }
    public DbSet<Advert> Adverts { get; set; }
    public DbSet<Category> Categories { get; set; }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
        // Customize the ASP.NET Identity model and override the defaults if needed.
        // For example, you can rename the ASP.NET Identity table names and more.
        // Add your customizations after calling base.OnModelCreating(builder);
    }
}

public class Advert
{
    public int ID { get; set; }
    public string Title { get; set; }
    public int CategoryID { get; set; }
    public virtual Category Category { get; set; }
    public int PortalUserID { get; set; }
    public PortalUser PortalUser { get; set; }
}

public class PortalUser : IdentityUser
{
    public string FirstName { get; set; }
    public string Surname { get; set; }
    public ICollection<Advert> Adverts { get; set; }

}

我在这里所做的是懒惰的普通虚拟映射加载目的。我正在将FK存储到广告字段中的PortalUser。

What I am doing here is normal virtual mapping for lazy loading purposes. I am storing FK to PortalUser in Advert field.

我将感谢每个有用的答案！

I will appreciate every helpful answer!

我已经知道了出来，不支持延迟加载，因此现在我的模型看起来像官方教程中的

I already figure out, that lazy loading is not supported so now my model looks like in the official tutorial:

> https://docs.microsoft.com/zh-cn/ef/core/get-started/aspnetcore/new- db

    public class BloggingContext : DbContext
{
    public BloggingContext(DbContextOptions<BloggingContext> options)
        : base(options)
    { }

    public DbSet<Blog> Blogs { get; set; }
    public DbSet<Post> Posts { get; set; }
}

public class Blog
{
    public int BlogId { get; set; }
    public string Url { get; set; }

    public List<Post> Posts { get; set; }
}

public class Post
{
    public int PostId { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }

    public int BlogId { get; set; }
    public Blog Blog { get; set; }
}

推荐答案

好的，伙计们，我找到了解决方案！所需要做的就是将属性PortalUserId的类型从int更改为string。比一切都编译，并且没有出现双倍字段！

Okay, guys, I found the solution! All what is needed, it is change type of property PortalUserId from int to string. Than everythings compiles and no doubled field appears!

至少感谢您的帮助！

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