使用EFcore不添加到數據庫中的對象列表

我想用.NET核心製作一個簡單的程序，該程序應該將插件和關聯的類別保存到MySQL數據庫中。使用EFcore不添加到數據庫中的對象列表

這兩個類存在：

public class Plugin 
{ 
    public string Name { get; set; } 

    public string Description { get; set; } 

    public List<Category> Categories { get; set; } 

    [Key] 
    public string ProjName { get; set; } 

    public string DownloadURL { get; set; } 
} 

public class Category 
{ 
    [Key] 
    public string UniqueName { get; set; } 

    public string PrettyName { get; set; } 
}

我使用這個語境：

public class Context : DbContext 
{ 
    public DbSet<Plugin> Plugins { get; set; } 

    public DbSet<Category> Categories { get; set; } 

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) 
     => optionsBuilder 
      .UseMySql(@"Server=XXX"); 
}

簡化代碼（沒有HttpClient的東西）看起來是這樣的：

public static async Task GetPluginsOnPage(string baseUri) 
{ 
    foreach (var plugin in pluginsOnPage) 
    { 
     List<Category> categories = new List<Category>(); 

     var nameHtml = "**"; 
     var descHtml = "**"; 
     var projName = "**"; 

     foreach (var x in plugin.***) 
     { 
      categories.Add(new Category() {PrettyName = "", UniqueName = "**" }); 
     } 

     var downloadUri = "**"; 

     await Ctx.Plugins.AddAsync(new Plugin { Categories = categories, Description = descHtml, Name = nameHtml, ProjName = projName, DownloadURL = downloadUri }); 
    } 

    await Ctx.SaveChangesAsync(); 
}

結果數據庫：