Code First with an existing database

I have a table in database which points to itse开发者_如何学编程lf, i.e. parent_id >> category id. This is the ER diagram

I have modelled this table like following, but it gives *Error : 'Category': member names cannot be the same as their enclosing type :

public class Category
{
    [Key]
    public int category_id { get; set; }
    public string category_name { get; set; }
    public int category_parent { get; set; }
    public string category_desc { get; set; }

    public virtual Category Category { get; set; }
}

How should I model such tables ?

You have to make category_parent nullable and configure navigational property Category to the scalar property category_parent. Try to use proper naming convensions.

public class Category
{
    [Key]
    [Column("category_id")]
    public int Id { get; set; }

    [Column("category_name")]
    public string Name { get; set; }

    [Column("category_parent")]
    public int? ParentId { get; set; }

    [Column("category_desc")]
    public string Description { get; set; }

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

I think you just need to change the Category property name to something else, so it is not the same as the class name...

public virtual Category SubCategory { get; set; }

public class Category
{
    [Key]
    public int category_id { get; set; }
    public string category_name { get; set; }
    public int category_parent { get; set; }
    public string category_desc { get; set; }

    public int parent_category_id { get; set; } <-- ADD & setup as foreign key
    public virtual Category ParentCategory { get; set; } <-- Change name

    public virtual ICollection<Category> Categories { get; set; }
}

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);

    modelBuilder.Entity<Category>.HasMany(cat => cat.Categories)
            .WithRequired()
            .HasForeignKey(cat => cat.parent_category_id);        
}