Entity Frameworks - adding 2 records with a FK:PK relationship - entity-framework

Question

I defined my 2 classes as:
public class User
{
public int Id { get; set; }
[Required]
public string Name { get; set; }
[Required]
public string Email { get; set; }
public Address Address { get; set; }
}
public class Address
{
public int Id { get; set; }
public string Street { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Zip { get; set; }
}
Note that I did not define an AddressId field in User. When EF creates the database for the above fields, it adds the User.AddressId column in the database and declares it an FK. So all good.
But now I want to insert data programmatically. I tried the following:
public class UserManagerDbContext: DbContext
{
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// add an address to database
Address addr = New Address
{
Id = 1,
Street = "John Doe",
City = "Boulder",
State = "CO",
Zip = "12345"
};
modelBuilder.Entity<User>()
.HasData(new User
{
Id = 1,
Name = "John Doe",
Email = "a#b.c",
Address = address
}
);
}
// ...
But that fails with the following exception:
System.InvalidOperationException: 'The seed entity for entity type 'User' cannot be added because no value was provided for the required property 'AddressId'.'
I understand why it's throwing this error - I need to enter both table entries separately and then, on inserting into the user table, include the AddressId value. But how can I do this? There is no AddressId field in the class.

Answer 1

You can try this
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// add an address to database
Address addr = new Address
{
Id = 1,
Street = "John Doe",
City = "Boulder",
State = "CO",
Zip = "12345"
};
modelBuilder.Entity<Address>()
.HasData(addr);
modelBuilder.Entity<User>()
.HasData(new User
{
Id = 1,
Name = "John Doe",
Email = "a#b.c",
AddressId = addr.Id,
}
);
}