Question

我有一个User-Entity，它将EntityBase作为父类。父类看起来像这样：

public class EntityBase
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public Guid Id { get; set; }

        public bool? IsPublic { get; set; }
        public bool? IsActive { get; set; }

        public DateTime CreatedAt { get; set; }
        public DateTime? UpdatedAt { get; set; }
        public DateTime? DeletedAt { get; set; }

        public virtual User CreatedBy { get; set; }
        public Guid? CreatedById { get; set; }

        public virtual User UpdatedBy  { get; set; }
        public Guid? UpdatedById { get; set; }

        public virtual User DeletedBy { get; set; }
        public Guid? DeletedById { get; set; }
    }

用户类：

public class User : EntityBase
{
    public string Username { get; set; }
    public string Email { get; set; }
    public string Password { get; set; }
    public string Token { get; set; }
    public DateTime LastLogin { get; set; }
    public DateTime LastAction { get; set; }
    public bool IsLocked { get; set; }
    public bool IsAdmin { get; set; }

    public virtual ICollection<Cocktail> Cocktails { get; set; }
    public virtual ICollection<Drink> DrinkVotes { get; set; }
    public virtual ICollection<Cocktail> CocktailVotes { get; set; }
}

现在我有自引用的问题，因为存在循环依赖，我该如何解决这个问题？

Answer 1

1）你的基础实体必须是抽象的

   public abstract class EntityBase ....

2）移动子类中的Id，例如UserId / CoktailId等（可选但推荐）

4）使用InverseProperty属性来引用鸡尾酒例如：http://www.entityframeworktutorial.net/code-first/inverseproperty-dataannotations-attribute-in-code-first.aspx

Answer 2

在您的上下文中，您需要覆盖OnModelCreating（DbModelBuilder），然后设置如下关系：

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<User>()
            .HasOptional(f => f.CreatedBy)
            .WithMany()
            .WillCascadeOnDelete(false);
    modelBuilder.Entity<User>()
            .HasOptional(f => f.UpdatedBy)
            .WithMany()
            .WillCascadeOnDelete(false);
    modelBuilder.Entity<User>()
            .HasOptional(f => f.DeletedBy)
            .WithMany()
            .WillCascadeOnDelete(false);
}

您将通过

删除此处的循环引用

说明CreatedBy，UpdatedBy和DeletedBy关系是可选的
在删除时禁用级联

代码首先自引用外键（多个）

2 个答案: