CODEWITHSUNDEEP
entity-frameworktable-per-type
Hemanshu Bhojak
Hemanshu Bhojak

Reputation: 17288

Table-per-type inheritance with EF 4.1 Fluent Code First

I have the following tables

Item
-------------------
ItemId (PK)
Name

Properties
-------------------
PropertyId (PK)
Name

ItemProperties
-------------------
ItemId (FK) (CPK)
PropertyId (FK) (CPK)
Value

and the following classes

class Item{
     ItemId;
     Name;
     Properties (Collection of type ItemProperty);
}

class Property{
     PropertyId;
     Name;
}

class ItemProperty : Property{
     Value;
}

Using EF Fluent API how do I map the above.

Upvotes: 0

Views: 328

Answers (1)

Ladislav Mrnka
Ladislav Mrnka

Reputation: 364249

To make @Eranga's comment more clear. Your database is not inheritance at all it is many-to-many relationship with additional data in junction table! It is mapped this way:

public class Item 
{
    public int ItemId { get; set; }
    public string Name { get; set; }
    public virtual ICollection<ItemProperty> Properties { get; set; }
}

public class Property
{
    public int PropertyId { get; set; }
    public string Name { get; set; }
    public virtual ICollection<ItemProperty> Items { get; set; }
}

public class ItemProperty
{
    public int ItemId { get; set; }
    public int PropertyId { get; set; }
    public int Value { get; set; }
    public virtual Item Item { get; set; }
    public virtual Property Property { get; set; }
}

And mapping:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<ItemProperty>().HasKey(ip => new { ip.ItemId, ip.PropertyId });

    modelBuilder.Entity<Item>()
                .HasMany(i => i.Properties)
                .WithRequired(ip => ip.Item)
                .HasForeignKey(ip => ip.ItemId); 
    modelBuilder.Entity<Property>()
                .HasMany(p => p.Items)
                .WithRequired(ip => ip.Property)
                .HasForeignKey(ip => ip.PropertyId); 
}

Upvotes: 1

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