如何在实体框架中将多个实体合二为一（将复杂实体映射为单表）

Question

Just for example. I have two models

public class Person {
    public int Id { get; set: }
    public string Name { get; set; }
    public Birth Date { get; set; }
}
public class Birth {
    public int Year { get; set; }
    public int Month { get; set; }
    public int Day { get; set; }
}

How to make the entity framework seeing the 'Person' entity like this:

public class Person {
    public int Id { get; set: }
    public string Name { get; set; }
    public int Year { get; set; }
    public int Month { get; set; }
    public int Day { get; set; }
}

ie EF should map it into single table.

Answer 1

If you are using EF Core this can be achieved with so called "Owned Entities" . Using atrributes:

public class Person 
{
    public int Id { get; set: }
    public string Name { get; set; }
    public Birth Date { get; set; }
}

[Owned]
public class Birth 
{
    public int Year { get; set; }
    public int Month { get; set; }
    public int Day { get; set; }
}

Or explicit configuration:

modelBuilder.Entity<Person>().OwnsOne(p => p.Date);

Note that Birth fields will be prefixed.