Types of inheritance in Entity Framework #TPH # TPT #TPC #ENTITY #ENTITYFRAMEWORK

 #TPH # TPT #TPC #ENTITY #ENTITYFRAMEWORK

1. Table-per-Hierarchy (TPH)

   The TPH inheritance states that all entities, in a hierarchy of entities, are mapped to a single table in storage schema. It means, there is only one table in database and different Entity types in Entity model that inherits from a base Entity are mapped to that table.

   

   C# Implementation Code for TPH

    public class Course
    {
    [Key]
    public int CourseId { get; set; }
    public string Name { get; set; }
    public string Details { get; set; }
    public string Trainer { get; set; }
    }
   
    public class OnlineCourse : Course
    {
    public string URL { get; set; }
    }
   
    public class OfflineCourse : Course
    {
    public string Address { get; set; }
    }
   

   Entity Framework Code First Mapping for TPH

   modelBuilder.Entity<Course>()
    .Map<OnlineCourse >(m => m.Requires("Type").HasValue("OnlineCourse "))
    .Map<OfflineCourse >(m => m.Requires("Type").HasValue("OfflineCourse "));
   

   
   

2. Table-per-Concrete-Type (TPC)

   The TPC inheritance states that each concrete class (a class which can be instantiated) in the hierarchy of entities is mapped to a separate table in storage schema. It means, there is separate table in database to maintain data for each derived entity type.

   

   C# Implementation Code for TPC

    public abstract class Course //abstract class
    {
    [Key]
    public int CourseId { get; set; }
    public string Name { get; set; }
    public string Details { get; set; }
    public string Trainer { get; set; }
    }
   
    public class OnlineCourse : Course //concrete class
    {
    public string URL { get; set; }
    }
   
    public class OfflineCourse : Course //concrete class
    {
    public string Address { get; set; }
    }
   

   Entity Framework Code First Mapping for TPC

   modelBuilder.Entity<OnlineCourse >().Map(m =>
   {
    m.MapInheritedProperties();
    m.ToTable("OnlineCourse ");
   });
   
   modelBuilder.Entity<OfflineCourse >().Map(m =>
   {
    m.MapInheritedProperties();
    m.ToTable("OfflineCourse ");
   });
   

   Note

   The TPC inheritance is commonly used to inherit basic features.

3. Table-per-Type (TPT)

   The TPT inheritance states that each entity in the hierarchy of entities is mapped to a separate table in storage schema. It means, there is separate table in database to maintain data for each Entity Type.

   

   C# Implementation Code for TPT

    public class Course
    {
    [Key]
    public int CourseId { get; set; }
    public string Name { get; set; }
    public string Details { get; set; }
    public string Trainer { get; set; }
    }
   
    public class OnlineCourse : Course
    {
    public string URL { get; set; }
    }
   
    public class OfflineCourse : Course
    {
    public string Address { get; set; }
    }
   

   Entity Framework Code First Mapping for TPT

   modelBuilder.Entity<Course>().ToTable("Course");
   modelBuilder.Entity<OnlineCourse >().ToTable("OnlineCourse ");
   modelBuilder.Entity<OfflineCourse >().ToTable("OfflineCourse ");