using  System;

using  System.Data;

using  System.Configuration;

using  System.Linq;

using  System.Xml.Linq;

using  System.Collections.Generic;

namespace  BookShop.Models

{

     public   partial   class  BookShopDBDataContext

    {

         // return all categories       

         public  List < Category >  GetAllCategory()

        {

             return  Categories.ToList();

        }

         // Add Category

         public   void  AddCategory(Category c)

        {

            

             this .Categories.InsertOnSubmit(c);

             this .SubmitChanges();

        }

         // Edit Category

         public   void  EditCategory(Category c)

        {

            

             this .UpdateCategory(c);

             this .SubmitChanges();

        }

         public  Category GetCategory( int  id)

        {

             return  Categories.Single(c  =>  c.CategoryId  ==  id);

        }

         // delete category

         public   bool  DelCategory( int  id)

        { 

             // check if has used

             if  (Books.Any(b  =>  b.BookCategoryId  ==  id))

            {

                 return   false ;

            }

             else

            {

                Category delCategory  =   this .Categories.Single(c  =>  c.CategoryId  ==  id);

                 this .Categories.DeleteOnSubmit(delCategory);

                 this .SubmitChanges();

                 return   true ;

            }

        }

    }

}