RegistrationCertificate_withInv.cs

    [Table("RegistrationCertificates")]
    public class RegistrationCertificate
    {
        [PrimaryKey, AutoIncrement]
        public int Id { get; set; }

        public string RegistrationNumber { get; set; }

        public string VIN { get; set; }

        public string OwnerData { get; set; }

        // added to have Inversion relationship
        [ForeignKey(typeof(Vehicle))]
        public int VehicleId { get; set; }

        [OneToOne]
        public Vehicle Vehicle { get; set; }
    }