Entity Framework Code First - Interfaces

Question

I would like to make app for restaurant. It´s about calculation recipes.

I have domain classes: - Ingredient - Recipe - RecipeItem

Recipe has List of RecipeItem.

RecipeItem could be Ingredient but also Recipe.

So I'm using Interface IItem with 2 properties(Id, Name). If I use Interface in my class, db generator ignore this field.

Look at my classes here:

public class Ingredient : IItem
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public double Price { get; set; }
    }

public class Recipe : IItem
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public List<RecipeItem> RecipeItems { get; set; }
    }

public class RecipeItem
    {
        public int Id { get; set; }
        public IItem Item { get; set; }
        public double Quantity { get; set; }
    }

CodeFirst automaticly generate for me database with tables above.

I would like to have database table RecipeItem looks likes:

> Id 
> Quantity 
> Recipe_Id - FK of Recipe ID 
> RecipePointer - Nullable FK of specific Recipe
> IngredientPointer - Nullable FK of specific Ingredient

But there are only:

> Id 
> Quantity 
> Recipe_Id - FK of Recipe ID

If I put into RecipeItem for example Ingredient, than Id of Ingredient will be inserted to IngredientPointer.

I would like to use FLUENT API for mapping but I don't know how.

I don't know if is possible what I want, or if is any better way how to solve my problem.

I watched already CodeFirst video on Pluralsight and I browse in forums but I can't find answer.

Thank you for any help.

tschmit · Accepted Answer · 2013-07-24 09:07:48Z

3

Not sure it can be done, but if it can, do not use an interface but a class, please try

public class Item
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class Ingredient : Item
{
    public double Price { get; set; }
}

public class Recipe : Item
{
    public List<RecipeItem> RecipeItems { get; set; }
}

public class RecipeItem
{
    public int Id { get; set; }
    public Item Item { get; set; }
    public double Quantity { get; set; }
}

Then you may want to read about EF and TPH

edited Jul 24, 2013 at 9:07

answered Jul 24, 2013 at 9:02

tschmit

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Eidivandi · Accepted Answer · 2016-05-29 13:08:58Z

0

you need to use the DataAnnotations to clarify it for EF how to generate the DB Generation Script

for your solution i can propose you

use the InversProperty and ForeignKey Attributes

have a look at the following resources :

https://msdn.microsoft.com/en-us/data/jj193542.aspx

https://msdn.microsoft.com/en-us/data/gg193958.aspx

answered May 29, 2016 at 13:08

Eidivandi

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