Foreign Key string constraint failed

[dandandandaann]

I have an issue like this: https://github.com/aspnet/EntityFrameworkCore/issues/16875 Except that my Key is String which is supposed to be already nullable.

I have these classes:

public class Transaction : Entity
{
    public string TransactionNumber { get; set; }
    public virtual ICollection<Movement> movements { get; set; }
}
public class Movement : Entity
{
    public int MovementId { get; set; }
    public string TransactionNumber { get; set; }
    public virtual Transaction Transaction { get; set; }
}

The configuration is setting the key:

builder.ToTable("Transaction");
builder.HasKey(d => d.TransactionNumber);

If I only create a new Movement with a TransactionNumber and save it I get a SqliteException: SQLite Error 19: 'FOREIGN KEY constraint failed'.. If a create both Movement and Transaction together it doesn't happen.
I tried changing the TransactionNumber to int? and it seems to work fine this way.

This issue is only happening in my test environment with Sqlite in memory creating the database codefirst. It's working fine in my production setup using MySql where the database is created independently.

Further technical details

EF Core version: Microsoft.EntityFrameworkCore 2.2.6 Database provider: Microsoft.EntityFrameworkCore.Sqlite 2.2.6 Target framework: NET Core 2.2

[AndriySvyryd]

@danielfdutra Please create a runnable project that shows this issue

[dandandandaann]

https://github.com/danielfdutra/EFCoreFKExceptionPoC

[smitpatel]

@danielfdutra - It throws exception because Transaction with TransactionNumber = C does not exist. A nullable FK property allows you to add Movement which does not belong to any Transaction but FK constraint will still block you to add Movement which references to a Transaction which does not exist.

[smitpatel]

@bricelam - I could not find the issue for unconstrainted relationships.

[AndriySvyryd]

https://github.com/aspnet/EntityFrameworkCore/issues/13146