This is with reference to @Ladislav Mrnka's answer on using fluent api for configuring one-to-one relationship.
Had a situation where having FK of dependent must be it's PK was not feasible.
E.g., Foo already has one-to-many relationship with Bar.
public class Foo {
public Guid FooId;
public virtual ICollection<> Bars;
}
public class Bar {
//PK
public Guid BarId;
//FK to Foo
public Guid FooId;
public virtual Foo Foo;
}
Now, we had to add another one-to-one relationship between Foo and Bar.
public class Foo {
public Guid FooId;
public Guid PrimaryBarId;// needs to be removed(from entity),as we specify it in fluent api
public virtual Bar PrimaryBar;
public virtual ICollection<> Bars;
}
public class Bar {
public Guid BarId;
public Guid FooId;
public virtual Foo PrimaryBarOfFoo;
public virtual Foo Foo;
}
Here is how to specify one-to-one relationship using fluent api:
modelBuilder.Entity<Bar>()
.HasOptional(p => p.PrimaryBarOfFoo)
.WithOptionalPrincipal(o => o.PrimaryBar)
.Map(x => x.MapKey("PrimaryBarId"));
Note that while adding PrimaryBarId needs to be removed, as we specifying it through fluent api.
Also note that method name [WithOptionalPrincipal()][1] is kind of ironic. In this case, Principal is Bar. WithOptionalDependent() description on msdn makes it more clear.