EF Core 多个一对多关系

Question

我正在构建简单的应用程序，使用 entity framework 来创建应该看起来像的关系。

public class Post
{
    public long Id { get; set; }
    public string Title;
    public ICollection<Comment> Comments { get; set; } = new List<Comment>();
    public ApplicationUser Owner { get; set; }
    public ICollection<Tag> Tags { get; set; } = new List<Tag>();
    public int LikesCount { get; set; }
}


public class ApplicationUser: IdentityUser
{
    public ICollection<Post> UserPost { get; set; } = new List<Post>();
    public ICollection<Post> LikedPosts { get; set; } = new List<Post>();
}

public class Comment : Auditable
{
    public long Id { get; set; }
    public string Content { get; set; }
}

public class Tag
{
    public long Id { get; set; }
    public string TagString { get; set; }
}

评论和标签是空的classes，只有索引。

如何在用户 User class 和 Post 之间创建正确的关系？

这就是我流利的结果api:

        builder.Entity<Post>(post =>
        {
            post.HasKey(p => p.Id);
            post.HasOne(p => p.Owner)
                .WithMany(u => u.LikedPosts)
                .HasForeignKey(p => p.Id)
                .OnDelete(DeleteBehavior.Cascade);

            post.HasOne(p => p.Owner)
                .WithMany(u => u.UserPost)
                .HasForeignKey(p => p.Id)
                .OnDelete(DeleteBehavior.Cascade);
        });

这让我出错，关系已经存在。我希望 sql 创建单独的表格来对喜欢和拥有的帖子进行分组。

感谢您的帮助。

Answer 1

我假设两个 ApplictionUser 可能喜欢同一个 Post，所以像这样：

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<Post>()
        .HasOne(p => p.Owner)
        .WithMany(u => u.UserPost)
        .OnDelete(DeleteBehavior.Restrict);

    modelBuilder.Entity<ApplicationUser>()
        .HasMany(u => u.LikedPosts)
        .WithMany(p => p.Likers);
        

    base.OnModelCreating(modelBuilder);
}

EF Core 多个一对多关系

EF Core Multiple one to many relationship

c#

entity-framework

relationship

.net-core