Owned types, complex types, value conversions and inheritance — Entity Framework (EF6 & EF Core)

6. Owned types, complex types, value conversions and inheritance

IntermediateMediumLesson 6 of 15

csharp

// Value object stored in the owner's table (Address_City, Address_Street columns)
b.Entity<Customer>().OwnsOne(c => c.Address);           // owned entity
b.Entity<Customer>().ComplexProperty(c => c.Address);    // EF Core 8 complex type (true value semantics)

// Enum stored as string
b.Entity<Order>().Property(o => o.Status).HasConversion<string>().HasMaxLength(20);

// JSON column (EF Core 7+)
b.Entity<Order>().OwnsOne(o => o.Metadata, m => m.ToJson());

Inheritance strategies:

Strategy	Tables	Pros/cons
TPH — Table per Hierarchy (default)	One table + discriminator column	Fastest queries; nullable columns
TPT — Table per Type	Base table + one per derived type	Normalised; joins make it slower
TPC — Table per Concrete type (EF 7)	One table per concrete class	No joins for concrete queries; IDs must be unique across tables