Entity Framework One-To-One [Answered]

Code at: https://paste.mod.gg/rccwzntafwoj/0

When attempting to change the database I'm getting:

The dependent side could not be determined for the one-to-one relationship between 'Room.Vet' and 'Vet.Room'. To identify the dependent side of the relationship, configure the foreign key property. If these navigations should not be part of the same relationship, configure them independently via separate method chains in 'OnModelCreating'. See http://go.microsoft.com/fwlink/?LinkId=724062 for more details.

OR

The property 'Room.Vet' is of type 'Vet' which is not supported by the current database provider. Either change the property CLR type, or ignore the property using the '[NotMapped]' attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.

I wanted to be able to create a Room that can have 0 or 1 Vets, and create a Vet that has 0 or 1 Rooms.

What am I doing incorrectly?

Thanks in advance.

You need to define the relationship explicitly

Might need .HasForeignKey() as well

I was currently doing:

            modelBuilder.Entity<Vet>()
                .HasOne(s => s.Room).WithOne(s => s.Vet)
                .IsRequired(false);

            modelBuilder.Entity<Room>()
                .HasOne(s => s.Vet).WithOne(s => s.Room)
                .IsRequired(false);

Which prompts the second error when trying to submit changes.

Configure only one side of the relationship, it's enough

Thank you, understood, but it continues with the same error (the first one).

What's your config now?

Same that's on the link for code so:

public class DataContext : IdentityDbContext<User>
    {
        public DataContext(DbContextOptions<DataContext> options) : base(options)
        {
        }

        public DbSet<Room> Rooms { get; set; }
        public DbSet<Vet> Vets { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Vet>()
                .HasOne(s => s.Room).WithOne(s => s.Vet)
                .IsRequired(false);
        }
    }

Still no .HasForeignKey<T>() I see

The docs you linked talk about it as well

I might be wrong, please tell me but I thing the .HasForeignKey() makes it so it cannot be nullable, or is that completely incorrect?

That's incorrect

.IsRequired() is what sets it

Also, make the key nullable just to make sure

So not public int VetId { get; set; } but public int? VetId { get; set; } for example

Shouldn't have assumed that .HasForeignKey() determined requirement. Thank you so much!

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