Code First 与父类别的一对多关系和类别

Question

public class Category
{
    [Key]
    public int CategoryId { get; set; }
    public int ParentCategoryId { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public int Status { get; set; }
    public virtual ICollection<Category> ParentCategories { get; set; }
    public virtual ICollection<ImageSet> ImageSets { get; set; }

    [ForeignKey("ParentCategoryId")]
    public virtual Category ParentCategory { get; set; }
}    

public class ImageSet
{
    [Key]
    public int ImageSetId { get; set; }
    public int CategoryId { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public string InsertDate { get; set; }
    public int Status { get; set; }
    public virtual ICollection<Image> Images { get; set; }

    [ForeignKey("CategoryId")]
    public virtual Category Category { get; set; }
}

public class Image
{
    [Key]
    public int ImageId { get; set; }
    public int ImageSetId { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
    public string ImageUrl { get; set; }
    public string ThumbImageUrl { get; set; }
    public string InsertDate { get; set; }
    public int Status { get; set; }

    [ForeignKey("ImageSetId")]
    public virtual ImageSet ImageSet { get; set; }
}

Context:
    public DbSet<Category> Categories { get; set; }
    public DbSet<Image> Images { get; set; }
    public DbSet<ImageSet> ImageSets { get; set; }

error page:Introducing FOREIGN KEY constraint 'FK_dbo.ImageSets_dbo.Categories_CategoryId' on table 'ImageSets' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. See previous errors.

有什么问题吗？

Answer 1

您需要添加：

modelBuilder.Entity<ImageSet>()
.HasRequired(is => is.Category)
.WithMany(c => c.ImageSets)
.WillCascadeOnDelete(false);

这里很好地解释了为什么会发生这种情况：