C#•2mo ago

Entity Framework Foreign Key restraint

Hi all, I'm trying to make an appointment scheduling system. The appointment section has its own database linked to a patients model and an appointment model. The error happens when I try save a new appointment -

_appointmentContext.SaveChanges();

_appointmentContext.SaveChanges();

These are my models:

    public class AppointmentDbContext : DbContext
    {
        public DbSet<Appointment> Appointments { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            // Set the file location for the patient database
            optionsBuilder.UseSqlite("Data Source=appointment.db");
        }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Appointment>()
                .HasOne(a => a.Patient)
                .WithMany(p => p.Appointments) // Matches Patient.Appointments
                .HasForeignKey(a => a.PatientId)
                .OnDelete(DeleteBehavior.Cascade);

            modelBuilder.Entity<Appointment>()
                .HasOne(a => a.User)
                .WithMany() 
                .HasForeignKey(a => a.UserId)
                .OnDelete(DeleteBehavior.Restrict);
        }

        public enum AppointmentStatus 
        {
            Completed = 1,
            Scheduled = 2,
            Cancelled = 3,


        } //UserAccountType

        public class Appointment
        {
            public int Id { get; set; }
            public DateTime Scheduled { get; set; }
            public AppointmentStatus Status { get; set; }

            //navigation properties 
            public int PatientId { get; set; }
            public Patient Patient { get; set; }
            public int UserId { get; set; }
            public User User { get; set; }
        }
    }
}

    public class AppointmentDbContext : DbContext
    {
        public DbSet<Appointment> Appointments { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            // Set the file location for the patient database
            optionsBuilder.UseSqlite("Data Source=appointment.db");
        }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Appointment>()
                .HasOne(a => a.Patient)
                .WithMany(p => p.Appointments) // Matches Patient.Appointments
                .HasForeignKey(a => a.PatientId)
                .OnDelete(DeleteBehavior.Cascade);

            modelBuilder.Entity<Appointment>()
                .HasOne(a => a.User)
                .WithMany() 
                .HasForeignKey(a => a.UserId)
                .OnDelete(DeleteBehavior.Restrict);
        }

        public enum AppointmentStatus 
        {
            Completed = 1,
            Scheduled = 2,
            Cancelled = 3,


        } //UserAccountType

        public class Appointment
        {
            public int Id { get; set; }
            public DateTime Scheduled { get; set; }
            public AppointmentStatus Status { get; set; }

            //navigation properties 
            public int PatientId { get; set; }
            public Patient Patient { get; set; }
            public int UserId { get; set; }
            public User User { get; set; }
        }
    }
}

5 Replies

AzimOP•2mo ago

    public class PatientDbContext : DbContext
    {
        public DbSet<Patient> Patients { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            // Set the file location for the patient database
            optionsBuilder.UseSqlite("Data Source=patients.db");
        }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Patient>()
            .HasMany(p => p.Appointments)
            .WithOne(a => a.Patient)
            .HasForeignKey(a => a.PatientId)
            .OnDelete(DeleteBehavior.Cascade);


           
        }
    }
    public class Patient
    {
        public int Id { get; set; } //Unique ID 
        public string FirstName { get; set; }
        public string Surname { get; set; }
        public DateTime DateOfBirth { get; set; }
        public string ContactDetail { get; set; }
        public string NHSNumber { get; set; }
        public string HospitalNumber { get; set; }
        public string HospitalRecords { get; set; }

        public ICollection <Appointment> Appointments { get; set; }

    } // class patients
} //namespace

    public class PatientDbContext : DbContext
    {
        public DbSet<Patient> Patients { get; set; }

        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            // Set the file location for the patient database
            optionsBuilder.UseSqlite("Data Source=patients.db");
        }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Patient>()
            .HasMany(p => p.Appointments)
            .WithOne(a => a.Patient)
            .HasForeignKey(a => a.PatientId)
            .OnDelete(DeleteBehavior.Cascade);


           
        }
    }
    public class Patient
    {
        public int Id { get; set; } //Unique ID 
        public string FirstName { get; set; }
        public string Surname { get; set; }
        public DateTime DateOfBirth { get; set; }
        public string ContactDetail { get; set; }
        public string NHSNumber { get; set; }
        public string HospitalNumber { get; set; }
        public string HospitalRecords { get; set; }

        public ICollection <Appointment> Appointments { get; set; }

    } // class patients
} //namespace

Angius•2mo ago

Why do you have two separate databases in the first place? Cross-database relationships are not really a thing

AzimOP•2mo ago

I realised after, first time dealing with database's and entity

Angius•2mo ago

Yeah, so, generally speaking you want to have a single database. It's easier this way DbContext represents the whole database DbSets within it, represent tables And the individual entities describe the columns of those tables

AzimOP•2mo ago

Fixed all of it, don't have any errors 🙂 thank you

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Entity Framework Foreign Key restraint