I am trying to create a many-to-many relationship between ApplicationUser and Reserve.
public class ApplicationUser : IdentityUser
{
public ApplicationUser()
{
this.Reserves = new HashSet<Reserve>();
}
public bool IsProfessional { get; set; }
public virtual ICollection<Reserve> Reserves { get; set; }
}
public class Reserve
{
public Reserve()
{
this.Usuarios = new HashSet<ApplicationUser>();
}
public int ID { get; set; }
public string Begin { get; set; }
public string End { get; set; }
public string Date { get; set; }
public string Status { get; set; } //free , reserved, confirmed, canceled
public DateTime LastUpdate { get; set; }
public virtual ICollection<ApplicationUser> Usuarios { get; set; }
}
But I cant add the migration
PM> Add-Migration user-reserve-relationship
Unable to determine the relationship represented by navigation property 'ApplicationUser.Reserves' of type 'ICollection<Reserve>'. Either manually configure the relationship, or ignore this property from the model.
Anyway, the same relationship works well to others entities but not ApplicationUser.
Can I use ApplicationUser many-to-many?
I found the follow in ef core :
Many-to-many relationships without an entity class to represent the join table are not yet supported.
So my question is closed.
Related
I want to add two properties from the city model:
after migration this error shows up:
Unable to determine the relationship represented by navigation
'City.Orders' of type 'ICollection'. Either manually configure
the relationship, or ignore this property using the '[NotMapped]'
attribute or by using 'EntityTypeBuilder.Ignore' in 'OnModelCreating'.
here is my code :
public class Order
{
public virtual City FromCity { get; set; }
public virtual City ToCity { get; set; }
}
public class City
{
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<Order> Orders { get; set; }
}
I suppose your model is more complicated than just FromCity and ToCity because I don't think it's a good idea to store such information in a different table. Yet, You can use inheritance in this case.
The table-per-hierarchy (TPH) pattern is used by default to map the inheritance in EF. TPH stores the data for all types in the hierarchy in a single table.
However, for your scenario, you can have a base class that holds all related attributes.
public class CityBase
{
public int Id { get; set; }
public string Name { get; set; } = string.Empty;
}
Then suppose you need two entities as per your scenario:
public class FromCity : CityBase
{
public virtual ICollection<Order> Orders { get; set; } = null!;
}
public class ToCity : CityBase
{
public virtual ICollection<Order> Orders { get; set; } = null!;
}
And the order entity:
public class Order
{
public int Id { get; set; }
public string OrderTitle { get; set; } = string.Empty;
public virtual FromCity FromCity { get; set; } = null!;
public virtual ToCity ToCity { get; set; } = null!;
}
This approach can solve your problem with a One-to-Many relationship between Orders and FromCity, ToCity as per below diagram:
I have a POCO Entity named Employee.
And then I have a second POCO Entity named Case.
I want a navigation property that looks like instead this:
public class Case : BaseEntity
{
public long EmployeeId { get; set; }
public virtual Employee Employee{ get; set; }
like this:
public class Case : BaseEntity
{
public long InitialContactId { get; set; }
public virtual Employee InitialContact { get; set; }
I want to name my property InitialContact. Not Employee.
But I get this error when EF tries to create the Database:
Unable to determine the relationship represented by navigation property 'Case.InitialContact' of type 'Employee'. Either manually configure the relationship, or ignore this property from the model.
Update 1:
I got it to work like this:
public class Case : BaseEntity
{
public long InitialContactId { get; set; }
[ForeignKey("Id")]
public virtual Employee InitialContact { get; set; }
public DateTime InitalConsultDate { get; set; }
public Guid AppUserId { get; set; }
public virtual AppUser LerSpecialist { get; set; }
}
The primary key is ID in my BaseEntity. Not EmployeeId.
But I have second part to my question.
Here is my Complete Employee POCO:
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using Hrsa.Core.Generic.Model.Framework.Concrete;
using Microsoft.AspNetCore.Mvc.ModelBinding;
namespace Hrsa.Core.Generic.Model.Lerd
{
public class Employee : BaseEntity
{
[BindNever]
public string Email { get; set; }
[BindNever]
public long OrganizationId { get; set; }
[BindNever]
public string Supervisor { get; set; }
[BindNever]
public string SupervisorEmail { get; set; }
[BindNever]
public string FirstName { get; set; }
[BindNever]
public string LastName { get; set; }
public string Notes { get; set; }
[BindNever]
public long BargainingUnitId { get; set; }
[BindNever]
public long PayPlanId { get; set; }
[BindNever]
public long GradeRankId { get; set; }
[BindNever]
public long PositionTitleId { get; set; }
[BindNever]
public long SeriesId { get; set; }
public bool IsUnionEmployee { get; set; }
public virtual Organization Organization { get; set; }
public virtual BargainingUnit BargainingUnit { get; set; }
public virtual PayPlan PayPlan { get; set; }
public virtual GradeRank GradeRank { get; set; }
public virtual PositionTitle PositionTitle { get; set; }
public virtual Series Series { get; set; }
public virtual ICollection<UnionHours> UnionHours { get; set; }
public virtual ICollection<Case> Cases { get; set; }
[NotMapped]
public string UnionEmployeeYesNo => (IsUnionEmployee) ? "Yes" : "No";
}
}
I want my Employee to have many Cases:
public virtual ICollection<Case> Cases { get; set; }
Here is my complete Cases POCO:
public class Case : BaseEntity
{
public long InitialContactId { get; set; }
[ForeignKey("Id")]
public virtual Employee InitialContact { get; set; }
public DateTime InitalConsultDate { get; set; }
public Guid AppUserId { get; set; }
public virtual AppUser LerSpecialist { get; set; }
}
So now my DB looks like this:
So I have my InitialContactId in Cases ok.
But now I need my Case to have many Employees.
So I add this in to my Case POCO:
public virtual ICollection<Employee> Employees { get; set; }
Now it looks like this:
public class Case : BaseEntity
{
public long InitialContactId { get; set; }
[ForeignKey("Id")]
public virtual Employee InitialContact { get; set; }
public DateTime InitalConsultDate { get; set; }
public Guid AppUserId { get; set; }
public virtual AppUser LerSpecialist { get; set; }
public virtual ICollection<Employee> Employees { get; set; }
}
Now when I run it, I get this error again:
Unable to determine the relationship represented by navigation property 'Case.InitialContact' of type 'Employee'. Either manually configure the relationship, or ignore this property from the model.
Update 2:
I found this article for a Many-Many relationship in .Net Core 1:
http://www.learnentityframeworkcore.com/configuration/many-to-many-relationship-configuration
So now I have a bridge lookup entity:
public class EmployeeCase
{
[ForeignKey("Id")]
public long EmployeeId { get; set; }
public Employee Employee { get; set; }
[ForeignKey("Id")]
public long CaseId { get; set; }
public Case Case { get; set; }
}
Employee POCO:
Changed:
public virtual ICollection<Case> Cases { get; set; }
to:
// Mapping - Collection of Cases
public virtual ICollection<EmployeeCase> EmployeeCases { get; set; }
Case POCO:
Changed:
public virtual ICollection<Employee> Employees { get; set; }
to:
// Mapping - Collection of Employees
public virtual ICollection<EmployeeCase> EmployeeCases { get; set; }
In my AppDbContext
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
#region Many-to-Many Employees Cases
modelBuilder.Entity<EmployeeCase>()
.HasKey(ec => new { ec.EmployeeId, ec.CaseId });
modelBuilder.Entity<EmployeeCase>()
.HasOne(ec => ec.Employee)
.WithMany(e => e.EmployeeCases)
.HasForeignKey(ec => ec.EmployeeId);
modelBuilder.Entity<EmployeeCase>()
.HasOne(ec => ec.Case)
.WithMany(c => c.EmployeeCases)
.HasForeignKey(ec => ec.CaseId);
#endregion
}
Now when I run I get this error:
An exception of type 'System.Data.SqlClient.SqlException' occurred in Microsoft.EntityFrameworkCore.Relational.dll but was not handled in user code
Additional information: Introducing FOREIGN KEY constraint 'FK_EmployeeCase_Employees_EmployeeId' on table 'EmployeeCase' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints.
Could not create constraint or index. See previous errors.
Update 3:
Finally got my tables the way I want with this piece of code from:
Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
// Get rid of Cascading Circular error on ModelBuilding
foreach (var relationShip in modelBuilder.Model.GetEntityTypes().SelectMany(e => e.GetForeignKeys()))
{
relationShip.DeleteBehavior = DeleteBehavior.Restrict;
}
#region Many-to-Many Employees Cases
modelBuilder.Entity<EmployeeCase>()
.HasKey(ec => new { ec.EmployeeId, ec.CaseId });
modelBuilder.Entity<EmployeeCase>()
.HasOne(ec => ec.Employee)
.WithMany(e => e.EmployeeCases)
.HasForeignKey(ec => ec.EmployeeId);
modelBuilder.Entity<EmployeeCase>()
.HasOne(ec => ec.Case)
.WithMany(c => c.EmployeeCases)
.HasForeignKey(ec => ec.CaseId);
#endregion
base.OnModelCreating(modelBuilder);
}
Update 4:
This did not work after all.
Remvoving the delete behavior for everything messes up my other relationships and I get errors.
How can I fix this?
This is disgusting.
So wishing I did not go Core.
Entity Framework uses conventions to guess how to map your C# model to database objects.
In your case you violate convention by custom name, so you should explain Entity Framework how to map this stuff.
There are two possible ways: attributes and fluent API. I'd suggest to use the latter one.
See section "Configuring a Foreign Key Name That Does Not Follow the Code First Convention" here: Entity Framework Fluent API - Relationships
I have made it a habit of explicitly defining my relationships as EF does not always get them the way I want. I like to create a Mapping folder that contains my entity maps. The fluent api works great for this and inherits from EntityTypeConfiguration.
Try this.
public class CaseMap : EntityTypeConfiguration<Case>
{
public CaseMap()
{
HasKey(m => m.Id)
HasRequired(m => m.InitialContact)
.WithMany(e => e.Cases)
.HasForeignKey(m => m.InitialContactId);
}
}
Almost forgot. You need to tell your DbContext where to find these mappings. Add this to your DbContexts OnModelCreating method.
modelBuilder.Configurations.AddFromAssembly(typeof(MyContext).Assembly);
This is what worked finally for the Cascading Delete circular references on the many-to-many in EF Core:
// Get rid of Cascading Delete Circular references error.
var type = modelBuilder.Model.GetEntityTypes().Single(t => t.Name == "Hrsa.Core.Generic.Model.Lerd.EmployeeCase");
foreach (var relationship in type.GetForeignKeys())
{
relationship.DeleteBehavior = DeleteBehavior.Restrict;
}
You have to get the Entity representing the many to many lookup only.
And from there restrict the DeleteBehavior.
I Got This Issue:
I Have the Application User Class Like This
public class ApplicationUser : IdentityUser
{
public ROLES Role { get; set; }
public int? CompanyId { get; set; }
public int? AreaId { get; set; }
public string Document { get; set; }
public bool Enable { get; set; }
[ForeignKey("CompanyId")]
public virtual Company Company { get; set; }
[ForeignKey("AreaId")]
public virtual Area Area { get; set; }
public virtual ICollection Measures { get; set; }
}
And I Got this another Model:
public class Area
{
public int AreaId { get; set; }
public string AreaName { get; set; }
public int CompanyId { get; set; }
public string UserId { get; set; }
[ForeignKey("CompanyId")]
public virtual Company Company { get; set; }
[Key, ForeignKey("UserId")]
public ApplicationUser ApplicationUser { get; set; }
}
And when i try to:
add-migration
the PM Console throws:
Unable to determine the principal end of an association between the types 'x.Models.ApplicationUser' and 'x.Models.Area'. The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations.
I have been trying all day but I can't find a way to tell the Entity Framework to recognize the relation.
Any ideas?
Thanks for reading
Add Attribute for AreaId in Area class
[Key]
public int AreaId { get; set; }
and if you want 1-1 relationship for ApplicationUser and Area update your code like
[Unique]
[ForeignKey("UserId")]
public ApplicationUser ApplicationUser { get; set; }
The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations
This Post give me the Answer I Need!!!
It's pretty hard to find...
So I let you the post here...
Thanks for all of your help!
I have two to be related entities as below :
public class VehicleExtraEntity
{
public int Id { get; set; }
public Guid NameKey { get; set; }
public virtual ICollection<WordEntity> WordsOfName { get; set; }
}
And the other entity :
public class WordEntity
{
public int Id { get; set; }
public string Content { get; set; }
public Guid Key { get; set; }
}
My purpose is write multi language supported db tables. For example ;
WordEntity1 : {Id=1, Content="Child Seat", Key="abcdef-12456"}
WordEntity2 : {Id=2, Content="Çocuk Koltuğu", Key="abcdef-12456"} --> Same Key
VehicleExtraEntity1 : {Id=1, NameKey = "abcdef-123456"}
I have tried fluent api but that support only relationships with navigation property. And it wants to me use many to many relationship. But I want resolve my problem as I wrote as above.
I have an EF code-first model with a table having several one-to-many relationships with other tables:
public class Note
{
[Key]
public Guid Id { get; set; }
public string NoteText { get; set; }
public string Author { get; set; }
public DateTime? CreationDate { get; set; }
}
public class Foo
{
public Foo()
{
Notes = new HashSet<Note>();
}
[Key]
public Guid Id { get; set; }
public virtual ICollection<Note> Notes { get; set; }
// other properties ommited...
}
public class Bar
{
public Bar()
{
Notes = new HashSet<Note>();
}
[Key]
public Guid Id { get; set; }
public virtual ICollection<Note> Notes { get; set; }
// other properties ommited...
}
As you can see, both Foo and Bar have their own list of Notes, but a Note belongs to either a Foo or a Bar.
When scaffolding the migration, EF creates a foreign key for Foo and Bar in the Notes table, which I think is not correct. I would like, instead, that a link table is created between Foo and Notes and another one between Bar and Notes.
Is there a way to automatically do this? Or do I have to manually create these classes in my code-first implementation?
This has already been answered in this other post!
But to save you a little googling, you are getting a one-to-many association, which is correct. you want a many-to-many relationship in your code, so what you will need to do is :
in your Notes class:
public class Note
{
[Key]
public Guid Id { get; set; }
public string NoteText { get; set; }
public string Author { get; set; }
public DateTime? CreationDate { get; set; }
public DateTime? CreationDate { get; set; }
public virtual ICollection<Foo> Foos { get; set; }
public virtual ICollection<Bar> Bars { get; set; }
}
Hope this helps