CODEWITHSUNDEEP
sql-serveref-core-3.1
Paul McTigue
Paul McTigue

Reputation: 221

EF Core 3.1 one-to-zero relationship

Entities

Person
    INT Id
    Address Adresss

Address
    INT Id
    INT PersonId

Model Builder

modelBuilder.Entity<Person>()
    .HasOne(p => p.Address)
    .WithOne()
    .IsRequired(false)
    .OnDelete(DeleteBehavior.Cascade)
    .HasForeignKey<Adresss>(a => a.PersonId)
    .IsRequired();

When Id do this

Person.Address = null

and then save changes. I get this error

The association between entity types 'Person' and 'Address' has been severed but the relationship is either marked as 'Required' or is implicitly required because the foreign key is not nullable.

I think the error is telling me to make PersonId (the foreign key) optional. So like below. Which is will result in the foreign key column being nullable in the SQL Server database. What I want is to allow for a user to delete an Address but if an address is added then it must contain a PersonId. So I don't want this to be null

Address
    INT Id
    INT? PersonId

Can make I make personId in the address table not null but also allow person's address property to be optional? in other words one to one OR one to zero relationship

Upvotes: 1

Views: 196

Answers (1)

AlbertoZ
AlbertoZ

Reputation: 164

I think that the best way to null Address is this:

Context.Address.Remove(Person.Address)

because Address is a DbSet, not only a navigation property. You have to mark the entity "Address" to be removed.

Upvotes: 1

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