Question

我想在ASP.NET Core中创建用户关系表并遇到一些问题。如果由于这个原因我必须禁用级联删除，我该如何防止孤儿？

错误：

    private void Refresh_Click(object sender, RoutedEventArgs e)
    {
        string url = @"https://api.twitch.tv/kraken/streams/camoduck?client_id=xskte44y2wfqin464ayecyc09nikcj";

        var json = new WebClient().DownloadString(url);

        Rootobject r = JsonConvert.DeserializeObject<Rootobject>(json);
        Console.WriteLine(r.stream);
        if r.stream.game = "Grand Theft Auto V"
        {
            _1GUnit1.Background = Brushes.Red;
        }


    }

ApplicationDbContext.cs：

Introducing FOREIGN KEY constraint 'FK_UserRelationships_AspNetUsers_User2Id' on table 'UserRelationships' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.

我目前的模特：

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
        builder.Entity<UserRelationship>().HasKey(x => new { x.User1Id, x.User2Id });
    }

    public DbSet<UserRelationship> UserRelationships { get; set; }
}

Answer 1

您可以根据需要使用ApplicationUsers，因此EF会默认将删除两次级联到同一个类（请参阅here）。

你需要告诉它不要：

builder.Entity<UserRelationship>().HasOne(ur => ur.User1).WithMany().HasForeignKey(ur => ur.UserId1).WillCascadeOnDelete(false);

builder.Entity<UserRelationship>().HasOne(ur => ur.User2).WithMany().HasForeignKey(ur => ur.UserId2).WillCascadeOnDelete(false);

创建用户关系表

1 个答案: