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Entity Framework Core: multiple relationships to one table of base type

Let's assume that Administrator, Purchaser and Supplier have User base type and remaining models look following:
public class Vendor
{
public int VendorId { get; set; }
public List<Supplier> Suppliers { get; set; }
}
public class Task
{
public int TaskId { get; set; }
public Administrator Admin { get; set; }
public List<Purchaser> Purchasers { get; set; }
public Vendor Vendor { get; set; }
}
Now I would like to create a UserTask table that contains IDs of all users of the Task: an Admin, Purchasers and Suppliers of the Vendor in column User and their Tasks IDs in column Task.
How could I configure such setup in Fluent API?
Edit:
I created additional entity UserTask that consists of IDs and navigation properties:
public class UserTask
{
public int UserId { get; set; }
public User User { get; set; }
public int TaskId { get; set; }
public Task Task { get; set; }
//some other needed properties
}
And tried to configure models like this:
modelBuilder.Entity<UserTask>(ut =>
{
ut.HasKey(x => new { x.UserId, x.TaskId });
ut.HasOne(u => u.User).WithMany()
.HasForeignKey(u => u.UserId)
.OnDelete(DeleteBehavior.Cascade);
ut.HasOne(t => t.Task).WithMany()
.HasForeignKey(t => t.TaskId)
.OnDelete(DeleteBehavior.Cascade);
});
modelBuilder.Entity<Task>(t =>
{
t.HasMany(p => p.Purchasers).WithMany(p => p.Tasks);
t.HasOne(a => a.Administrator).WithMany(); //adding a => a.Task expression in parameter throws error that the relationship is already defined
t.HasMany(s => s.Vendors.Suppliers).WithMany(s => s.Tasks); //throws error
});
And it fails because HasMany(s => s.Vendors.Suppliers) i not a valid member access expression. Is there any way to overcome this issue?

Considering the relationships in these tables, add a property so that Fluent API can reference the relationship. About the specific modelbuilder.
modelBuilder.Entity<Supplier>()
.HasOne(x => x.vendor)
.WithMany(y => y.Suppliers);
modelBuilder.Entity<Administrator>()
.HasOne(a => a.tasks)
.WithOne(t => t.Admin)
.HasForeignKey<Administrator>(f=>f.AdministratorId);
modelBuilder.Entity<Vendor>()
.HasOne(a => a.tasks)
.WithOne(t => t.Vendor)
.HasForeignKey<Vendor>(f=>f.VendorId);
The model need to be redesigned as this.
public class User
{
public int id { get; set; }
public string Property { get; set; }
}
public class Vendor
{
public int VendorId { get; set; }
public List<Supplier> Suppliers { get; set; }
public Tasks tasks { get; set; }
}
public class Tasks
{
[Key]
public int TaskId { get; set; }
public Administrator Admin { get; set; }
public List<Purchaser> Purchasers { get; set; }
public Vendor Vendor { get; set; }
}
public class Supplier:User
{
public int SupplierId { get; set; }
public string SupplierProperty { get; set; }
public Vendor vendor { get; set; }
}
public class Administrator:User
{
public int AdministratorId { get; set; }
public string adminProperty { get; set; }
public Tasks tasks { get; set; }
}
public class Purchaser:User
{
public int PurchaserId { get; set; }
public string purProperty { get; set; }
public Tasks tasks { get; set; }
}

One to Many relationship always bring me empty

I try to use Entity Framework with code first and fluent api to implement a one to many relationship
I have two classes
namespace Mantenimiento.Business.Entities
{
public class Personal : Entity
{
[Key]
public int Id { get; set; }
public int? Dni { get; set; }
public string Nombre { get; set; }
public string Apellido { get; set; }
public string Cuil { get; set; }
public string Legajo { get; set; }
[ForeignKey("Dni")]
public ICollection<ContactoEmergencia> Contacto { get; set; }
}
namespace Mantenimiento.Business.Entities
{
public class ContactoEmergencia : Entity
{
[Key]
public int Id { get; set; }
public int? Dni { get; set; }
public string ApellidoNombre { get; set; }
public string Vinculo { get; set; }
public string Domicilio { get; set; }
public string telefono { get; set; }
public string Comentario { get; set; }
public int CreateUserId { get; set; }
[ForeignKey("Dni")]
public virtual Personal Personal { get; set; }
}
}
This is my dbContext
#region personals
modelBuilder.Entity<Personal>().ToTable("InfoPersonal").HasKey(t => t.Id);
modelBuilder.Entity<Personal>().Property(c => c.Id).UseSqlServerIdentityColumn().IsRequired();
modelBuilder.Entity<Personal>().Property(c => c.CreatedDate).HasDefaultValue(DateTime.Now);
modelBuilder.Entity<Personal>().Property(c => c.LastModifiedDate).HasDefaultValue(DateTime.Now);
modelBuilder.Entity<Personal>().Property(c => c.Deleted).HasDefaultValue(false);
modelBuilder.Entity<Personal>().HasMany<ContactoEmergencia>(c => c.Contacto).WithOne(p => p.Personal).HasForeignKey(s => s.Dni);
#endregion
#region contactoEmergencias
modelBuilder.Entity<ContactoEmergencia>().ToTable("InfoEmergencia").HasKey(d => d.Dni);
modelBuilder.Entity<ContactoEmergencia>().Property(c => c.CreatedDate).HasDefaultValue(DateTime.Now);
modelBuilder.Entity<ContactoEmergencia>().Property(c => c.LastModifiedDate).HasDefaultValue(DateTime.Now);
modelBuilder.Entity<ContactoEmergencia>().Property(c => c.Deleted).HasDefaultValue(false);
#endregion
And my query is
return await _context.personals
.Include(c => c.Contacto)
.Where(p => p.Deleted == false)
.OrderBy(s => s.Apellido)
.ToListAsync(
);
But the properties is always empty.
i need to relate Personal.Di with Contacto.Dni, i had to change the key?

You should remove ForeignKey attribute from Personal entity. In one to many relationship only child entity could accept ForeignKey.

AutoMapper Infinite Loop using EF Code First

I have the following classes (One-One relationship Asset-TrackingDevice):
public class Asset
{
public int Id { get; set; }
public string Name { get; set; }
public TrackingDevice TrackingDevice { get; set; }
}
public class TrackingDevice
{
public int Id { get; set; }
public string Imei { get; set; }
public int? AssetId { get; set; }
public Asset Asset { get; set; }
}
The viewModels are very similar:
public class AssetViewModel
{
public int Id { get; set; }
public string Name { get; set; }
public int? TrackingDeviceId { get; set; }
public TrackingDeviceViewModel TrackingDevice { get; set; }
}
public class TrackingDeviceViewModel
{
public int Id { get; set; }
public string Imei { get; set; }
public AssetViewModel Asset { get; set; }
public string AssetId { get; set; }
}
Mappings:
CreateMap<Asset, AssetViewModel>()
.ForMember(d => d.TrackingDevice, map => map.Ignore());
CreateMap<AssetViewModel, Asset>()
.ForMember(d => d.TrackingDevice, map => map.Ignore());
CreateMap<AssetViewModel, Asset>()
.ReverseMap();
CreateMap<TrackingDevice, TrackingDeviceViewModel>()
.ForMember(d => d.Asset, map => map.Ignore());
CreateMap<TrackingDeviceViewModel, TrackingDevice>()
.ForMember(d => d.Asset, map => map.Ignore());
CreateMap<TrackingDevice, TrackingDeviceViewModel>()
.ReverseMap();
When I perform a database query to obtain the TrackingDevices,
I get an error because in the mapping the Asset within Tracking Device also includes a Tracking Device and so on.
The query that I execute to obtain the tracking devices is:
var trackingDevices = _appContext.TrackingDevices
.Include(td => td.Asset)
.ToListAsync();
var trackingMapper = Mapper.Map<IEnumerable<TrackingDeviceViewModel>>(trackingDevices);
I read that by including the Map.Ignore would fix the problem but it did not work either, does anyone know what my error is?

Entity Framework Core Navigation Properties Error

I'm trying to make a simple app to try Entity Framework Core, but i a have problem with setting up relations between entities. My entities:
public class Card
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public string Adress { get; set; }
public DateTime DoB { get; set; }
public DateTime DoS { get; set; }
public User Portal { get; set; }
public List<Reservation> Res { get; set; }
}
public class Doctor
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
public string Surname { get; set; }
public string Email { get; set; }
public TimeSpan Start_Working { get; set; }
public TimeSpan End_Working { get; set; }
public List<Reservation> Reservations { get; set; }
public int SpecID { get; set; }
public Spec Spec { get; set; }
}
public class Reservation
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public DateTime DoR { get; set; }
public string Info { get; set; }
public int CardID { get; set; }
public Card Card_Nav_R { get; set; }
public int DoctorID { get; set; }
public Doctor Doctor { get; set; }
}
public class Spec
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
public List<Doctor> Doctors { get; set; }
}
public class User
{
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Email { get; set; }
public string Password { get; set; }
public int CardID { get; set; }
public Card Card { get; set; }
}
And a configuration class where i tried to set up relations:
class ApplicationContext:DbContext
{
public DbSet<User> Users { get; set; }
public DbSet<Card> Cards { get; set; }
public DbSet<Reservation> Reservations { get; set; }
public DbSet<Doctor> Doctors { get; set; }
public DbSet<Spec> Specs { get; set; }
public ApplicationContext()
{
Database.EnsureCreated();
}
protected override void OnModelCreating(ModelBuilder ModelBuilder)
{
ModelBuilder.Entity<User>().HasKey(u => u.Id);
ModelBuilder.Entity<Card>().HasKey(c => c.Id);
ModelBuilder.Entity<Doctor>().HasKey(d => d.Id);
ModelBuilder.Entity<Spec>().HasKey(s => s.Id);
ModelBuilder.Entity<Reservation>().HasKey(r => r.Id);
ModelBuilder.Entity<User>().Property(u => u.Email).IsRequired();
ModelBuilder.Entity<User>().Property(u => u.Password).IsRequired();
ModelBuilder.Entity<Card>().Property(c => c.Name).IsRequired();
ModelBuilder.Entity<Card>().Property(c => c.Surname).IsRequired();
ModelBuilder.Entity<Card>().Property(c => c.DoB).IsRequired();
ModelBuilder.Entity<Card>().Property(c => c.Adress).IsRequired();
ModelBuilder.Entity<Doctor>().Property(d => d.Name).IsRequired();
ModelBuilder.Entity<Doctor>().Property(d => d.Surname).IsRequired();
ModelBuilder.Entity<Doctor>().Property(d => d.Spec).IsRequired();
ModelBuilder.Entity<Doctor>().Property(d => d.Email).IsRequired();
ModelBuilder.Entity<Doctor>().Property(d => d.Start_Working).IsRequired();
ModelBuilder.Entity<Doctor>().Property(d => d.End_Working).IsRequired();
ModelBuilder.Entity<Reservation>().Property(r => r.Info).IsRequired();
ModelBuilder.Entity<Reservation>().Property(r => r.Card_Nav_R).IsRequired();
ModelBuilder.Entity<Reservation>().Property(r => r.Doctor).IsRequired();
ModelBuilder.Entity<Reservation>().Property(r => r.DoR).IsRequired();
ModelBuilder.Entity<Spec>().Property(s => s.Name).IsRequired();
ModelBuilder.Entity<Doctor>().HasOne<Spec>(d=>d.Spec).WithMany(s => s.Doctors).HasForeignKey(d => d.SpecID);
ModelBuilder.Entity<User>().HasOne<Card>(u => u.Card).WithOne(c => c.Portal).HasForeignKey<User>(u => u.CardID);
ModelBuilder.Entity<Reservation>().HasOne<Card>(r => r.Card_Nav_R).WithMany(c => c.Res).HasForeignKey(r => r.CardID);
ModelBuilder.Entity<Reservation>().HasOne<Doctor>(r => r.Doctor).WithMany(d => d.Reservations).HasForeignKey(r => r.DoctorID);
}
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer("Server=(localdb)\\mssqllocaldb;Database=Simple_Try;Trusted_Connection=True;");
}
}
So, when i tried to add migration or add something to database i saw this error:
System.InvalidOperationException: 'The property or navigation 'Spec' cannot be added to the entity type 'Doctor' because a property or navigation with the same name already exists on entity type 'Doctor'.'
I really don't know how to fix this, i tried to use annotations instead of Fluent API, but had the same result.

The cause of the exception is the following line:
ModelBuilder.Entity<Doctor>().Property(d => d.Spec).IsRequired();
because Doctor.Spec is a navigation property
public class Doctor
{
// ...
public Spec Spec { get; set; }
}
and navigation properties cannot be configured via Property fluent API.
So simply remove that line. Whether reference navigation property is required or optional is controlled via relationship configuration. In this case
ModelBuilder.Entity<Doctor>()
.HasOne(d => d.Spec)
.WithMany(s => s.Doctors)
.HasForeignKey(d => d.SpecID)
.IsRequired(); // <--
although the IsRequired is automatically derived from the FK property type - since SpecID is non nullable, then the relationship is required.
For more info, see Required and Optional Properties and Required and Optional Relationships documentation topics.

Merge multiple sources into a single destination

I want to combine 2 Domain Objects into a single data transfer object using AutoMapper.
Domain Model:
public class Service {
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public ICollection<DownloadService> DownloadServices { get; set; } = new HashSet<DownloadService>();
}
public class DownloadService {
public int Id { get; set; }
public int PageLimit { get; set; }
public virtual int ServiceId { get; set; }
public virtual Service Service { get; set; }
}
public class Volume {
public override int Id { get; set; }
public bool IsActive { get; set; }
public string Path { get; set; }
public string Description { get; set; }
}
DTO:
public class PreferenceVM {
public ICollection<VolumeVM> Volumes { get; set; }
public ICollection<ServiceVM> Services { get; set; }
}
public class ServiceVM {
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public ICollection<DownloadServiceVM> DownloadServices { get; set; } = new HashSet<DownloadServiceVM>();
}
public class DownloadServiceVM {
public int Id { get; set; }
public int PageLimit { get; set; }
public int CleaningInterval { get; set; }
}
public class VolumeVM {
public int Id { get; set; }
public bool IsActive { get; set; }
public string Path { get; set; }
public string Description { get; set; }
}
Mapping:
cfg.CreateMap<Volume, VolumeVM>().ReverseMap();
cfg.CreateMap<DownloadService, DownloadServiceVM>().ReverseMap();
cfg.CreateMap<Service, ServiceVM>()
.ForMember(d => d.DownloadServices, opt => opt.MapFrom(s => s.DownloadServices))
.ReverseMap();
cfg.CreateMap<ICollection<Volume>, PreferenceVM>()
.ForMember(x => x.Volumes, y => y.MapFrom(src => src)).ReverseMap();
cfg.CreateMap<ICollection<Service>, PreferenceVM>()
.ForMember(x => x.Services, y => y.MapFrom(src => src)).ReverseMap();
when I try the mapping above:
var services = serviceRepository.GetAll();
var volumes = volumeRepository.GetAll();
var entities = mapper.Map<PreferenceVM>(services);
entities = mapper.Map(volumes, entities);
I get the following errors:
Missing type map configuration or unsupported mapping.
Mapping types: EntityQueryable1 -> PreferenceVM
Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryable1[[Fwims.Core.Data.Model.Setting.Service,
Fwims.Core.Data.Model, Version=1.0.1.10, Culture=neutral,
PublicKeyToken=null]] -> Fwims.Core.ViewModel.Setting.PreferenceVM
It looks like my mapping is wrong, nothing I have tried has worked. How do I properly map the Domain objects to the Data transfer objects?

Here
cfg.CreateMap<ICollection<Volume>, PreferenceVM>()
.ForMember(x => x.Volumes, y => y.MapFrom(src => src)).ReverseMap();
and
cfg.CreateMap<ICollection<Service>, PreferenceVM>()
.ForMember(x => x.Services, y => y.MapFrom(src => src)).ReverseMap();
you create mappings from ICollection<TSource>.
However later on you are trying to map IQeryable<TSource>. While AutoMapper can use a base mapping to map a derived class, IQueryable<T> does not derive from ICollection<T>, hence the missing type map exception.
The solution is to create a mapping from some common base interface of IQueryable<T> and ICollection<T>, which is IEnumerable<T>.
So replace the above with:
cfg.CreateMap<IEnumerable<Volume>, PreferenceVM>()
.ForMember(x => x.Volumes, y => y.MapFrom(src => src));
cfg.CreateMap<IEnumerable<Service>, PreferenceVM>()
.ForMember(x => x.Services, y => y.MapFrom(src => src));
and the current issue will be solved.
Note that ReverseMap does not work in such scenarios, so I've just removed it. If you need such functionality, you have to create that mappings manually (eventually using ConvertUsing because there is no destination member).