Hi i am running into some issues when trying to do an update on a nested collection using Entity Framework. I am using Entity Framework Core but I don't know if that make a difference with this issue.
The application should allow people to be tagged and untagged in a photo.
I am using WebApi and trying to send a patch to update some details but the update doesn't seem to work.
Here is the data model:
Here is my Photo class
public class Photo
{
private Photo() { }
public Photo(string title, string location)
{
CreatedDate = DateTime.UtcNow;
Title = title;
Location = location;
Persons = new HashSet<PersonPhoto>();
}
public int Id { get; set; }
public string Title { get; private set; }
public string Location { get; private set; }
public DateTime CreatedDate { get; private set; }
public ICollection<PersonPhoto> Persons { get; set; }
}
Here is my Person class
public class Person
{
public Person()
{
Photos = new HashSet<PersonPhoto>();
}
public Person(string firstName, string lastName, DateTime dateOfBirth)
{
FirstName = firstName;
LastName = lastName;
DateOfBirth = dateOfBirth;
CreatedDate = DateTime.UtcNow;
}
public int Id { get; set; }
public string FirstName { get; private set; }
public string LastName { get; private set; }
public DateTime? DateOfBirth { get; private set; }
public DateTime CreatedDate { get; private set; }
public DateTime? LastModified { get; set; }
public ICollection<PersonPhoto> Photos { get; set; }
}
Here is my PersonPhoto class
public class PersonPhoto
{
public int PersonId { get; set; }
public Person Person { get; set; }
public int PhotoId { get; set; }
public Photo Photo { get; set; }
}
I am sending a JsonPatch document containing a PhotoViewModel to the endpoint and I would expect the result to either update or remove a record for the PhotoPerson joining table.
Here is the PhotoViewModel
public class PhotoViewModel
{
public int Id { get; set; }
public string Title { get; set; }
public string Location { get; set; }
public List<int> Persons { get; set; }
}
Here is the endpoint that I am posting to:
public IActionResult TagPhoto(int id, [FromBody]JsonPatchDocument<PhotoViewModel> patch)
{
// Get Photo first
var photos = _uow.Photos.GetPhoto(id);
var photoVM = Mapper.Map<Photo, PhotoViewModel>(photos);
patch.ApplyTo(photoVM);
var photo = Mapper.Map<PhotoViewModel, Photo>(photoVM);
foreach (var i in photoVM.Persons)
{
photo.Persons.Add(new PersonPhoto()
{
PersonId = i
});
}
_uow.Photos.UpdatePhoto(photo);
_uow.Complete();
return Ok();
}
The mapper that maps a PhotoViewModel to a Photo Entity looks like this:
Mapper.CreateMap<PhotoViewModel, Photo>()
.ForMember(dest => dest.Persons,
opts => opts.Ignore());
The mapper that maps a Photo Entity to a PhotoViewModel looks like this:
Mapper.CreateMap<Photo, PhotoViewModel>()
.ForMember(vm => vm.Persons,
map => map.MapFrom(p => p.Persons.Select(c => c.PersonId)));
and the Repository that handles the data access has this update method:
public void UpdatePhoto(Photo photo)
{
contextTest.Entry(photo).State = EntityState.Modified;
}
Whats currently happening:
If I update the PhotoViewModel properties other than the collection of Persons then the database is updated accordingly. Sql Profiler shows that the update statement contains the new property change (title for example) however when I try to update the nested collection nothing happens in the database and sql profiler has no mention of the nested collection. It just seems to ignore it.
I've tried a few different things. I changed the repository to update like this:
_context.Photos.Update(photo)
This just kept adding new records into the joining table (duplicates too) when I would try to remove from the nested collection nothing would every be removed from the joining table.
Am I missing something really obvious? I've been looking around online but I can't really see a solution for this.
Any help would be very much appreciated!
** Edit **
The _context.SaveChanges() ocurrs in my UnitOfWork here:
public void Complete()
{
_context.SaveChanges();
}
Related
I am struggling a bit to wrap my head around Entity Framework and It's driving me crazy. I have an target object that I'd like to populate:
public class ApiInvitationModel
{
public int Id { get; set; }
public EventModel Event { get; set; }
public UserModel InvitationSentTo { get; set; }
public UserModel AttendingUser { get; set; }
}
The schemas of the above models are:
public class EventModel {
public int Id? { get; set; }
public string Name { get; set; }
public DateTime? StartDate { get; set; }
public DateTime? EndDate { get; set }
public OrganizationModel HostingOrganization { get; set; }
public Venue Venue { get; set; }
public string Price { get; set; }
}
public class UserModel {
public int Id? { get; set; }
public string Name { get; set; }
public string PhoneNumber { get; set; }
public string MobileNumber { get; set; }
public List<OrganizationModel> Organizations { get; set; }
}
public class OrganizationModel {
public int Id? { get; set; }
public stirng Name { get; set; }
public string Address { get; set; }
public UserModel PrimaryContact { get; set; }
}
The above schemas are simplified for the purpose of the question and are the models we intend to return via API.
The problem is the origin schemas in the database is very different and I'm trying to map the database objects to these objects via Entity Framework 6.
My attempted solution was to try and nest the models via a query but that didn't work and I'm not sure where to go from here besides making numerous calls to the database.
public List<ApiInvitationModel> GetInvitations(int userId) {
using (var entities = new Entities()) {
return entities.EventInvitations
.Join(entities.Users, invitation => invitiation.userId, user => user.id, (invitation, user) => new {invitation, user})
.Join(entities.Events, model => model.invitation.eventId, ev => ev.id, (model, ev) => new {model.invitation, model.user, ev})
.Join(entities.organization, model => model.user.organizationId, organization => organization.id, (model, organization) => new ApiInvitationModel
{
Id = model.invitation.id,
Event = new EventModel {
Id = model.event.id,
Name = model.event.name,
StartDate = model.event.startDate,
EndDate = model.event.endDate,
HostingOrganization = new OrganizationModel {
Id = model.invitation.hostingId,
Name = model.event.venueName,
Address = model.event.address,
PrimaryContact = new UserModel {
Name = model.event.contactName,
PhoneNumber = model.event.contactNumber,
}
}
...
},
InvitedUser = {
}
}
).ToList();
}
}
As you can see above, there's quite a bit of nesting going on but this doesn't work in Entity Framework 6 as far as I am aware. I keep getting the following errors:
"The type 'Entities.Models.API.UserModel' appears in two structurally incompatible initializations within a single LINQ to Entities query. A type can be initialized in two places in the same query, but only if the same properties are set in both places and those properties are set in the same order.",
Based on the above error, I assumed that each of the model initiatilizations would need to be the same (i.e. initializing the values as the same ApiInvitationModel in each join in the same order) but that produces the same error.
What would be the best approach to handling this, keepign in mind the source database doesn't have foreign keys implemented?
I am using Entity Framework code first with fluent API I have an items table with foreign keys from users and units tables
but when I load the table to ObservableCollection then bind it to a datagrid the table normal column load it's data normally into the datagrid excpet for the foreign keys which show nothing but when i insert a break point to see the data inside the ObservableCollection I can see that every thing from Users and Units table is there
private void MainContentsWindow_ContentRendered(object sender, EventArgs e)
{
using (var db2 = new DataContext())
{
var AllItems2 = new ObservableCollection<Model.Items.Item>(db2.Items);
ItemsDataGrid.ItemsSource = AllItems2;
}
}
Users
public class User
{
public User()
{
Id = Guid.NewGuid();
IsActive = false;
}
public Guid Id { get; set; }
public string Name { get; set; }
public string Password { get; set; }
public UserGroup Group { get; set; }
public bool IsActive { get; set; }
public virtual ICollection<Items.Item> Items { get; set; } = new List<Items.Item>();
}
public enum UserGroup
{
Administrator = 1,
User,
Unknown
}
base
public class NormalBaseModel : CommonBase
{
public NormalBaseModel()
{
Id = new Guid();
CreateDate = DateTime.Now;
EditDate = null;
}
public Guid Id { get; set; }
public string Notes { get; set; }
public virtual User CreateBy { get; set; }
public DateTimeOffset? CreateDate { get; set; }
public virtual User EditBy { get; set; }
public DateTimeOffset? EditDate { get; set; }
}
items
public class Item : NormalBaseModel
{
public string NameAr { get; set; }
public string NameEn { get; set; }
public int? ManualId { get; set; }
public string Barcode { get; set; }
public byte?[] Image { get; set; }
public virtual Unit Unit { get; set; }
public string MadeIn { get; set; }
public bool IsSerail { get; set; }
public bool IsExpire{ get; set; }
}
Here is a test project on Github
https://github.com/ahmedpiosol/psychic-parakeet.git
https://imgur.com/a/zimd4
When you load your items via EF it needs to create new instances of User and Item. Behind the scenes, EF will call the constructor for each new instance. Your problem is in your constructors:
public User()
{
Id = Guid.NewGuid(); // <- here
}
Your constructor reassigns a new ID each time an instance is created, this will break the referential integrity and cause all sorts of other problems.
Your code doesn't know the difference between creating a new User and recreating a User instance from the database.
I suggest removing the assignments from inside your constructor and placing this either in a static Create method or place wherever you are creating a new User or Item.
p.s. WPF is irrelevant to your problem here.
Fluent API needs to specify foreign key in code, something like
modelBuilder.Entity<Items>()
.HasRequired(o => o.User)
.WithMany(c => c.Items)
.HasForeignKey(o => o.UserId);
I have two entities:
public class Booking
{
[Key]
public int Id { get; set; }
public int RoomId { get; set; }
[ForeignKey("RoomId")]
public Room Room { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string DocumentNumber { get; set; }
public string ContactPhone { get; set; }
}
public class Room
{
[Key]
public int RoomId { get; set; }
public int Number { get; set; }
public int Size { get; set; }
public bool HasBalcony { get; set; }
public int Beds_1 { get; set; }
public int Beds_2 { get; set; }
public double DayPrice { get; set; }
public List<Booking> Bookings { get; set; }
...
public int BookingsCount()
{
return Bookings.Count;
}
public bool IsFree(DateTime dateTime)
{
MessageBox.Show(BookingsCount().ToString());
return true;
}
}
and DbContext:
public class HotelContext : DbContext
{
public DbSet<Employee> Employees { get; set; }
public DbSet<Room> Rooms { get; set; }
public DbSet<Booking> Bookings { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Booking>()
.HasRequired(b => b.Room)
.WithMany(r => r.Bookings)
.HasForeignKey(b => b.RoomId);
}
}
When MessageBox.Show is called I'm getting exception: An unhandled exception of type 'System.NullReferenceException' occurred in Hotel.exe
When I'm trying to access Room::Bookings, the list is always null. There is one row in Bookings table and multiple rows in Rooms table.
How can I load all of Bookings into Room object?
Depends where you are in the learning curve, however some things stand out
Firstly
You either want to create a relationship via FluentApi or Annotations, not both
Ie. you have this on your Room entity
[ForeignKey("RoomId")]
And this in fluent
modelBuilder.Entity<Booking>()
.HasRequired(b => b.Room)
.WithMany(r => r.Bookings)
.HasForeignKey(b => b.RoomId);
You need to pick one or the other, otherwise you may end-up with multiple Ids in your Booking i.e RoomId and Room_Id
Secondly
If you want to be able to Lazy Load bookings you need to make Bookings collection Virtual
public virtual List<Booking> Bookings { get; set; }
Lastly
To access your data (presuming your connection string is correct)
using(var db = new HoteContext())
{
var rooms = db.Rooms.Include(x => x.Bookings).ToList();
}
Note : Although EF Lazy loads relationships, you might want to make sure you have included the Room->Booking relationship
Consider the following code.
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
namespace ConsoleApp
{
class Program
{
static void Main(string[] args)
{
using (MyDbContext dbContext = new MyDbContext())
{
dbContext.Departments.Add(new Department()
{
Name = "Some Department1",
Employees=new List<Employee>()
{
new Employee() { Name = "John Doe" }
}
});
dbContext.SaveChanges();
var department = dbContext.Departments.FirstOrDefault(d => d.Name == "Some Department1");
if (department.Employees != null)
{
foreach (var item in department.Employees)
{
Console.WriteLine(item.Name);
}
}
}
}
}
public class Department
{
public int Id { get; set; }
public string Name { get; set; }
public List<Employee> Employees { get; set; }
}
public class Employee
{
public int Id { get; set; }
public string Name { get; set; }
}
public class MyDbContext : DbContext
{
public DbSet<Department> Departments { get; set; }
public DbSet<Employee> Employees { get; set; }
}
}
If you have the code in above way, the control will not go into if condition, because department.Employees is null. Now, change the Department entity as follows.
public class Department
{
public int Id { get; set; }
public string Name { get; set; }
public virtual List<Employee> Employees { get; set; }
}
And now you should be able to see control go into if condition and outputs the employees name.
That is called Lazy Loading.
If you want to eagerly load, you don't have to put virtual to the property. You can Include the properties as follows.
var department = dbContext.Departments.Include(d => d.Employees).FirstOrDefault(d => d.Name == "Some Department1");
Now you can see the employees names are getting outputted.
You will absolutely run into performance trouble with your design here.
The temptation with EF is to completely map your object model to the DB and have EF do all the magic for you behind the scenes. But you need to think about it in terms of only getting specifically what you need from the db at any point in time. Otherwise you will get all kinds of cartesian product issues. I highly suggest you get yourself a copy of Hibernating Rhino's EF Profiler or similar so you can analyze your code statically and at runtime for EF performance issues (and see what SQL it is generating). For this what you want is a purpose built call to the DB to get the count. Otherwise what will happen is you will pull the entire table of Bookings and then have C# give you the count. That only makes sense if you want to do something with the whole list. Two options would be:
1) Create a VIEW against the Bookings table and map that to EF. The view would look something like SELECT ROOMS.ROOMID, COUNT(*) - you map this view to your model and voila now you have a list of counts by room (id) and you can use them individually or sum it up to get your total count for all rooms. If you have 1,000 bookings in 10 rooms, you are getting back only 10 rows from the DB. Whereas with your design, you are pulling back all 1,000 bookings with all their fields and then filtering down in C#. Bad juju.
2) The architecturally and conceptually simpler approach is going to be to do a direct query as such (obviously this returns only a single int from the db):
public int BookingsCount()
{
int count = 0;
try
{
using (var context = new HotelContext())
{
var sql ="SELECT COUNT(*) FROM Bookings WHERE ROOMID=" + this.RoomId;
count = context.Database.SqlQuery<int>(sql).First();
}
} catch (Exception ex)
{
// Log your error, count will be 0 by default
}
return count;
}
A simple solution would be making the Bookings property virtual.
public class Room
{
[Key]
public int RoomId { get; set; }
public int Number { get; set; }
public int Size { get; set; }
public bool HasBalcony { get; set; }
public int Beds_1 { get; set; }
public int Beds_2 { get; set; }
public double DayPrice { get; set; }
public virtual List<Booking> Bookings { get; set; }
}
More information on Entity Framework Loading Related Entities,
https://msdn.microsoft.com/en-us/library/jj574232(v=vs.113).aspx
I am facing the same issue as described in this question. Problem: my method GetAllConferences() returns correctly all the conferences from the DB, but when I return the result to the View from the controller return Ok(tripListVm) inly the first collection item is returned to the client. On the otehr side, by setting to null all the FK references (as pointed out in the SO question above) I can return correctly all the entities to the client, however this does not seem to me the proper way of proceeding.
EDIT: the solution was much simpler than I though. In the code below (I leave it in its original form for others to see it) I was not mapping the FK entities inside the ViewModel to Dto objects, but returning the model entity itself. That was the reason why I needed to null those inner references to make it work. By returning all Dtos objects, it works properly.
I have three entities involved with 1-many relationships:
public class Conference
{
public int Id { get; set; }
[Required]
[MaxLength(50)]
public string Name { get; set; }
public ICollection<Venue> Venues { get; set; }
public int? LocationId { get; set; }
public Location Location { get; set; }
}
public class Venue
{
public int Id { get; set; }
[Required]
[MaxLength(50)]
public string Name { get; set; }
public int? ConferenceId { get; set; }
public Trip Conference { get; set; }
public int? LocationId { get; set; }
public City City { get; set; }
}
public class City
{
public int Id { get; set; }
[Required]
[MaxLength(50)]
public string Name { get; set; }
public ICollection<Conference> Conferences { get; set; }
public ICollection<Venue> Venues { get; set; }
}
In the repository, I have a method that returns the conferences and the related entities (City and Venues):
public IEnumerable<Conference> GetAllConferences()
{
return _context.Conferences
.Include(t => t.Venues)
.Include(t => t.City)
.ToList();
}
In the controller I need to use the following code to return all the results:
var conferences = _repository.GetAllConferences();
if (conferences.Any())
{
var conferenceListVm = trips.ToConferenceVmList();
//Without setting the FK references to null, I can return only the first result of the collection
foreach (var vm in conferenceListVm)
{
foreach (var pm in vm.PoinOfInterests)
{
pm.Trip = null;
}
vm.Location.Conferences = null;
vm.Location.Venues = null;
}
return Ok(conferenceListVm);
}
public static ConferenceViewModel ToConferenceVm(this Conference conference)
{
var confVm = new ConferenceViewModel();
confVm.Name = conference.Name;
confVm.City = conference.City;
confVm.Venues = conference.Venues;
return tripVm;
}
public static IEnumerable<ConferenceViewModel> ToConferenceVmList(this IEnumerable<Conference> conferences)
{
return conferences.Select(c => c.ToConferenceVm()).ToList();
}
I have a simple entity framework 6 code first from existing database project for my web application. When I save data sometimes it saves properly with only 1 record saved. However sometimes it saves 2, 3 5 records it appears random.
For simplicity sake I have the following 2 classes. One is a parent "Person", and "PersonAddress" is the child. In my application there will always be 2 child records to 1 parent. No more no less (dont ask why). Here are my classes which are bare bones.
[Table("Person")]
public partial class Person
{
[Key]
public int PersonID { get; set; }
public string FirstName { get; set; }
public string MiddleName { get; set; }
public string LastName { get; set; }
[Required]
public virtual ICollection<PersonAddress> PersonAddresses { get; set; }
}
[Table("PersonAddress")]
public partial class PersonAddress
{
[Key]
public int PersonAddressID { get; set; }
public int PersonID { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Zipcode { get; set; }
}
Here is my DBContext class
public partial class MyDBContext : DbContext
{
public MyDBContext()
: base("name=MyDBContext")
{
//skips database initialization so it wont track changes and produce error, not needed for code first
Database.SetInitializer<MyDBContext>(null);
}
public virtual DbSet<Person> Persons { get; set; }
public virtual DbSet<PersonAddress> PersonAddresses { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Person>().Property(x => x.PersonID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
modelBuilder.Entity<PersonAddress>().Property(x => x.PersonAddressID).HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
}
}
//sample code
Person person = new Person();
person.FirstName = "TestFName";
person.LastName = "TestLName";
List<PersonAddress> addresses = new List<PersonAddress>();
PersonAddress address1 = new PersonAddress();
address1.Address1 = "line1"
//etc
//etc
addresses.Add(address1);
PersonAddress address2 = new PersonAddress();
address1.Address2 = "line1"
//etc
//etc
addresses.Add(address2);
//now add addresses to Person
person.PersonAddresses = addresses;
using (var context = new MyDBContext())
{
context.Persons.Add(person);
context.SaveChanges();
obj.PersonID = obj.PersonID;
}
What am I doing wrong, the data always gets saved and the child records are automatically added when I save the parent without issue. But as previously stated sometimes numerous sets of records are saved and I dont see any reason why. Thanks
Try this:
using (var context = new MyDBContext())
{
Person.PersonAdresses.add(addres1);
Person.PersonAdresses.add(addres2);
context.Entry(Person).State=EntityState.Added;
context.SaveChanges();
};