How to deal with Foreign key relationships Entity Framework MVC - c#

public class UserCommentry
{
[Key]
public int ID { get; set; }
[ForeignKey("AccountID")]
public int AccountID { get; set; }
public virtual Account account { get; set; }
public Int64 TransferID { get; set; }
}
Primary key Field
public class Account
{
[Key]
public int ID { get; set; }
public int code{ get; set; }
public Int64 TransferID { get; set; }
Error:
The property 'AccountID' cannot be configured as a navigation property. The property must be a valid entity type and the property should have a non-abstract getter and setter. For collection properties the type must implement ICollection where T is a valid entity type.

Short answer: it's because navigarion property should be of type you want it to point to.
If I wanted to create a relationship with an account, I would do it this way:
public class UserCommentry
{
[Key]
public int ID { get; set; }
public Account Account{ get; set; }
public virtual Account account { get; set; }
public Int64 TransferID { get; set; }
}
And then let context know about it using OnModelCreating. You can read more here http://www.entityframeworktutorial.net/code-first/configure-one-to-many-relationship-in-code-first.aspx

Related

Invalid ForeignKeyAttribute name with Entity Framework in code first approach

I have the following models
public class Team
{
[Key,DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
[ForeignKey("User")]
public int ManagerId { get; set; }
public virtual User User { get; set; }
}
Here is my User class:
public class User
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
[ForeignKey("Comapny")]
public int CompanyId { get; set; }
public virtual Company Company { get; set; }
}
Here is my Company class:
public class Company
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string Name { get; set; }
}
When I try to add a new migration I get the following error
The ForeignKeyAttribute on property 'CompanyId' on type
'ReportsEngine.Areas.Test.Models.User' is not valid. The navigation
property 'Comapny' was not found on the dependent type
'ReportsEngine.Areas.Test.Models.User'. The Name value should be a
valid navigation property name.
What am I doing wrong here?
Its just a typo, Company instead of Comapany
[ForeignKey("Company")]
public int CompanyId { get; set; }
[ForeignKey("Comapny")] indicates that the property to use for the foreign key to the Company table should be Comapny.
The error is because you have not defined a Comapny property on the Company table.
Add the following to the Company table:
public int Comapny { get; set; }
Obviously it may be better to prefix it with Id just to show it is that type of field.
Or you could omit the [ForeignKey] attribute to let Entity Framework code first add one for you.

Entity framework Code First One-to-One relationship

I have two entities which I want to be connected 1:1 relationship. User is principal and UserActivation is dependent, but I have no idea how that works.
public class User
{
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
public string Lastname { get; set; }
public string Username { get; set; }
public virtual UserActivation UserActivation { get; set; }
}
public class UserActivation
{
[Key]
public Guid Id { get; set; }
public Guid UserId { get; set; }
public bool Active { get; set; }
public virtual User User { get; set; }
}
I have tried to remove 'virtual' keyword, have tried to add ForeignKey("UserId") or ForeignKey("User"), I've even tried to make [Key, ForeignKey("User") and none of them helped me. I want to make 1:1 relationship using only dataannotations. Any help is really appreciated. Also my both classes has their own PKs.
Foreign keys are not supported for 1:1 try:
public class User
{
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
public string Lastname { get; set; }
public string Username { get; set; }
public virtual UserActivation UserActivation { get; set; }
}
public class UserActivation
{
[Key]
[ForeignKey("User")]
public Guid Id { get; set; }
public bool Active { get; set; }
public virtual User User { get; set; }
}
Unable to determine the principal end of an association between the types ‘Model.PersonPhoto’ and ‘Model.Person’. The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations.
Julie Lehrman discusses this in her Code First book:
"This problem is most easily solved by using a ForeignKey annotation
on the dependent class to identify that it contains the foreign key.
When configuring one-to-one relationships, Entity Framework requires
that the primary key of the dependent also be the foreign key. In our
case PersonPhoto is the dependent and its key, PersonPhoto.PersonId,
should also be the foreign key. Go ahead and add in the ForeignKey
annotation to the PersonPhoto.PersonId property, as shown in Example
4-21. Remember to specify the navigation property for the relationship
when adding the ForeignKey annotation."
This post is quite old so I thought I'd post the EF 6 solution
Try this...
public class User
{
[Key]
public Guid Id { get; set; }
public string Name { get; set; }
public string Lastname { get; set; }
public string Username { get; set; }
public virtual UserActivation UserActivation { get; set; }
}
public class UserActivation
{
[ForeignKey("User")]
public Guid Id { get; set; }
public Guid UserId { get; set; }
public bool Active { get; set; }
public virtual User User { get; set; }
}

Entity Framework foreign key not found during migration

I'm experiencing an unexpected error when setting up a migration after adding keys and foreign keys to my data model. I'm using VS2013 Express, with .NET framework 4.5.
When creating a data model for Entity Framework, because the relationship keys between classes aren't what is expected by convention, I'm using data annotations as outlined in the MS Data Developer Center. Here's the class code:
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace BacklogTracker.Models
{
public class WorkOrder
{
[Key]
public string woNum { get; set; }
public string woClosingStatus { get; set; }
[ForeignKey("ID")]
public virtual ICollection<Note> woNotes { get; set; }
[ForeignKey("machSN")]
public virtual Machine woMachine { get; set; }
[ForeignKey("ID")]
public virtual ICollection<Segment> woSegments { get; set; }
}
public class Machine
{
[Key]
public string machSN { get; set; }
public string machLocation { get; set; }
public string machModel { get; set; }
}
public class Segment
{
[Key]
public int ID { get; set; }
public uint segNum { get; set; }
public string segRepair { get; set; }
[ForeignKey("ID")]
public virtual ICollection<Note> segNotes { get; set; }
}
public class Note
{
[Key]
public int ID { get; set; }
public DateTime notetimestamp { get; set; }
public string notestring { get; set; }
}
}
However, when I try to perform a migration after updating the model by performing enable-migrations in the package manager console, I get the following error:
The ForeignKeyAttribute on property 'woMachine' on type
'BacklogTracker.Models.WorkOrder' is not valid. The foreign key name
'machSN' was not found on the dependent type
'BacklogTracker.Models.WorkOrder'. The Name value should be a comma
separated list of foreign key property names.
Why is my foreign key name 'machSN' not being found?
I think you have some errors in your model. Default Code First convention for ForeignKey relationship expected to have declared a foreign key property in the dependend end (WorkOrder) that match with primary key property of the principal end (Machine). It is not necessary that they have the same name, check this link. So, declare a property named machSN in your WorkOrder class:
public class WorkOrder
{
[Key]
public string woNum { get; set; }
public string woClosingStatus { get; set; }
public virtual ICollection<Note> woNotes { get; set; }
public string machSN { get; set; }
[ForeignKey("machSN")]
public virtual Machine woMachine { get; set; }
public virtual ICollection<Segment> woSegments { get; set; }
}
You can find other errors in the woNotes and woSegments navigation properties. In this side of a one-to-many relationship you don't declare a FK, is in the other side, in Note and Segment classes, for example:
public class Note
{
[Key]
public int ID { get; set; }
public DateTime notetimestamp { get; set; }
public string notestring { get; set; }
[ForeignKey("Order)]
public string woNum { get; set; }
public virtual WorkOrder Order{get;set;}
}
Delete also in the Segment class the ForeignKey attribute over segNotes navigation property for the same reasons explained before.
public class Segment
{
[Key]
public int ID { get; set; }
public uint segNum { get; set; }
public string segRepair { get; set; }
public virtual ICollection<Note> segNotes { get; set; }
}

Entity Framework 6 - foreign key issue

I have the following model using EF6, where I'm trying to link a 'ContentArticleHOAsubdivision' entity to a 'SubdivisionHOA':
public partial class ContentArticleHOAsubdivision
{
public int Id { get; set; }
[ForeignKey("ContentArticleHOA")]
public long ContentArticleId { get; set; }
[ForeignKey("SubdivisionsHOA")]
public short SubdivisionId { get; set; }
public virtual ContentArticleHOA ContentArticleHOA { get; set; }
public virtual ICollection<SubdivisionHOA> SubdivisionsHOA { get; set; }
}
public partial class SubdivisionHOA
{
public short Id { get; set; }
public string Name { get; set; }
[ForeignKey("TopTierDivisionHOA")]
public byte TopTierDivisionId { get; set; }
public virtual TopTierDivisionHOA TopTierDivisionHOA { get; set; }
}
I get the error:
The foreign key component 'SubdivisionId' is not a declared property on type 'SubdivisionHOA'. Verify that it has not been explicitly excluded from the model and that it is a valid primitive property.
The 'Id' property in SubdivisionHOA I'm trying to link on needs to be named 'Id' as that's the name of the actual column in the database, so I'm not sure what I need to do?
I've tried adding [InverseProperty("Id")] before the [ForeignKey] attributes but get the same error.
Basicly the foreign key usage in EntityFramework seems like this:
public partial class ContentArticleHOAsubdivision
{
public int Id { get; set; }
...
public virtual ICollection<SubdivisionHOA> SubdivisionsHOAs { get; set; }
}
public partial class SubdivisionHOA
{
public short Id { get; set; }
...
public int ContentArticleHOAsubdivisionId { get; set; }
[ForeignKey("ContentArticleHOAsubdivisionId")]
public virtual ContentArticleHOAsubdivision ContentArticleHOAsubdivision { get; set; }
}
Just based on your code, and I have discard some unknown stuffs.

Relationships in Entity Framework Code First

yesterday I created database in Management Studio and now I want to create it in program using EF Code First.
Here is link to my database: http://s11.postimg.org/6sv6cucgj/1462037_646961388683482_1557326399_n.jpg
And what I did:
public class GameModel
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public DateTime CreationTime { get; set; }
public DateTime StartTime { get; set; }
public DateTime EndTime { get; set; }
public string TotalTime { get; set; }
public DateTime RouteStartTime { get; set; }
public DateTime RouteEndTime { get; set; }
public int MaxPlayersPerTeam { get; set; }
public int CityId { get; set; }
public int CreatorId { get; set; }
[InverseProperty("Id")]
[ForeignKey("CreatorId")]
//public int TeamId { get; set; }
//[ForeignKey("TeamId")]
public virtual UserModel Creator { get; set; }
public virtual CityModel City { get; set; }
//public virtual TeamModel WinnerTeam { get; set; }
}
public class RegionModel
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public virtual ICollection<CityModel> Cities { get; set; }
}
public class CityModel
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public int RegionId { get; set; }
public virtual RegionModel Region { get; set; }
public virtual ICollection<UserModel> Users { get; set; }
public virtual ICollection<GameModel> Games { get; set; }
}
public class UserModel
{
[Key]
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Login { get; set; }
public string Password { get; set; }
public string Email { get; set; }
public DateTime RegistrationDate { get; set; }
public string FacebookId { get; set; }
public int CityId { get; set; }
public virtual CityModel City { get; set; }
public virtual IEnumerable<GameModel> Games { get; set; }
}
For now I wanted to create 4 tables but I have some problems... I want to make CreatorId in GameModel, but it doesn't work... When i wrote UserId instead of CreatorId it was working ( without [InverseProperty("Id")] and [ForeignKey("CreatorId")]).
This is what i get:
The view 'The property 'Id' cannot be configured as a navigation property. The property must be a valid entity type and the property should have a non-abstract getter and setter. For collection properties the type must implement ICollection where T is a valid entity type.' or its master was not found or no view engine supports the searched locations.
edit:
I changed it like this:
public int CityId { get; set; }
public int CreatorId { get; set; }
[ForeignKey("CityId")]
public virtual CityModel City { get; set; }
[ForeignKey("CreatorId")]
public virtual UserModel Creator { get; set; }
And there is another problem.
The view 'Introducing FOREIGN KEY constraint 'FK_dbo.UserModels_dbo.CityModels_CityId' on table 'UserModels' 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. See previous errors.' or its master was not found or no view engine supports the searched locations.
And I have no idea how to solve it.
The InversePropertyAttribute specifies, which navigation property should be used for that relation.
A navigation property must be of an entity type (the types declared in your model, GameModel for example) or some type implementing ICollection<T>, where T has to be an entity type. UserModel.Id is an int, which clearly doesn't satisfy that condition.
So, the inverse property of GameModel.Creator could be UserModel.Games if you changed the type to ICollection<GameModel>, or had to be left unspecified. If you don't specify an inverse property, EF will try to work everything out on its own (in this case it would properly recognize GameModel.Creator as a navigation property, but UserModel.Games would most likely throw an exception, as it is neither an entity type, nor does it implement ICollection<T> with T being an entity type, nor is it a primitive type from a database point of view). However, EF's work-everything-out-by-itself-magic doesn't cope too well with multiple relations between the same entity types, which is when the InversePropertyAttribute is needed.
A quick example that demonstrates the problem:
class SomePrettyImportantStuff {
[Key]
public int ID { get; set; }
public int OtherId1 { get; set; }
public int OtherId2 { get; set; }
[ForeignKey("OtherId1")]
public virtual OtherImportantStuff Nav1 { get; set; }
[ForeignKey("OtherId2")]
public virtual OtherImportantStuff Nav2 { get; set; }
}
class OtherImportantStuff {
[Key]
public int ID { get; set; }
public virtual ICollection<SomePrettyImportantStuff> SoldStuff { get; set; }
public virtual ICollection<SomePrettyImportantStuff> BoughtStuff { get; set; }
}
Here, EF knows that it has to generate 2 FKs from SomePrettyImportantStuff to OtherImportantStuff with the names Id1 and Id2, but it has no way to tell which of the IDs refers to the entity where it was sold from and which is the one it was bought from.
Edit: How to fix the cyclic reference problem
To fix that problem, your context class should override OnModelCreating and configure the foreign keys which shouldn't cascade on delete accordingly, like this:
protected override void OnModelCreating(DbModelBuilder builder)
{
builder.Entity<CityModel>().HasMany(c => c.Users).WithRequired(u => u.City)
.HasForeignKey(u => u.CityId).WillCascadeOnDelete(value: false);
// Add other non-cascading FK declarations here
base.OnModelCreating(builder);
}

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