Relationship between tables - c#

I use sqlmembership provider and that creates some tables. I need its user table.
My application has three types of users: teachers, students and other users. So I thought of three tables for them.
Each of them has a username which is registered by membership provider and saved in its own tables.
Now I don't know how to make the relationship between teachers or students tables to their usernames saved in the table of memberships, using entity framework.
I thought I can add a one to one relationship between users table created by membership provider and my tables after reverse engineering created tables by it to code first, but it seems is not allowed to change those tables.
Can someone show me how to make a relationship between teachers or students to their usernames (I mean their membership information)?
More Details: here are code first tables
public class aspnet_Users
{
public aspnet_Users()
{
this.aspnet_PersonalizationPerUser = new List<aspnet_PersonalizationPerUser>();
this.aspnet_Roles = new List<aspnet_Roles>();
}
public System.Guid ApplicationId { get; set; }
public System.Guid UserId { get; set; }
public string UserName { get; set; }
public string LoweredUserName { get; set; }
public string MobileAlias { get; set; }
public bool IsAnonymous { get; set; }
public System.DateTime LastActivityDate { get; set; }
public virtual aspnet_Applications aspnet_Applications { get; set; }
public virtual aspnet_Membership aspnet_Membership { get; set; }
public virtual ICollection<aspnet_PersonalizationPerUser> aspnet_PersonalizationPerUser { get; set; }
public virtual aspnet_Profile aspnet_Profile { get; set; }
public virtual ICollection<aspnet_Roles> aspnet_Roles { get; set; }
}
public class Techer
{
[Key]
public int TeacherId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string NationalNumber { get; set; }
public string PhoneNumber { get; set; }
public string Description { get; set; }
public int OfficeId { get; set; }
public virtual Office Office { get; set; }
}
public class Student
{
public int StudentId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public int OfficeId { get; set; }
public virtual Office Office { get; set; }
}

I've encountered a similar scenario, and what I ended up doing is creating a foreign key from my user profile table(s) to the membership table. So for example, the Teacher table would have a column called MembershipId, and it would foreign key to the Id column in the membership table. Then, in the Register action of my AccountController, I have something like this:
if (db.Memberships.Any(x => x.UserName == model.UserName)
{
// handle error here
// return view with error message "user name already in use"
}
var token = WebSecurity.CreateUserAndAccount(model.UserName, model.Password, null, true);
var membership = db.Memberships.SingleOrDefault(x => x.UserName == model.UserName);
if (membership != null)
{
var newProfile = new Teacher
{
Membership = membership
// add other properties here if required
}
db.Teachers.Add(newProfile);
db.SaveChanges();
}
*This code is untested, as I don't have VS available at the moment, but should be enough to get you on the right track.

Related

Many to Many relationship with ApplicationUser

I am building a Code-First, Many-To-Many relationship between my ApplicationUser class and a Lesson class. When the model is created, Entity Framework builds the two tables and the intersecting pivot table. However, neither table seems to take in data from the pivot table (LessonApplicationUsers). Both List variables do not seem to hold either the list of Students or the list of Lessons. Both entities i'm trying to marry up already exist in the database
ApplicationUser class
public class ApplicationUser : IdentityUser
{
public string Address { get; set; }
public int? Age { get; set; }
public ClassLevel? ClassLevel { get; set; }
public string FirstName { get; set; }
public int? Height { get; set; }
public string LastName { get; set; }
public string MobileNumber { get; set; }
public string Postcode { get; set; }
public string Town { get; set; }
public int? Weight { get; set; }
public ApplicationUser()
{
Lessons = new List<Lesson>();
}
public ICollection<Lesson> Lessons { get; set; }
}
Lesson Class
public class Lesson
{
[Key]
public int LessonID { get; set; }
public LessonType ClassType { get; set; }
public ClassLevel? ClassLevel { get; set; }
public DateTime ClassStartDate { get; set; }
public DateTime ClassEndDate { get; set; }
public float ClassCost { get; set; }
public int? InstructorID { get; set; }
public Lesson()
{
Students = new List<ApplicationUser>();
}
public ICollection<ApplicationUser> Students { get; set; }
public enum LessonType {Group,Private}
}
My DBContext
public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
public DbSet<Lesson> Lessons { get; set; }
public DbSet<ApplyViewModel> Applications { get; set; }
And finally, the code i'm using to add in the pivot table data. This is activated when the user presses a button on the booking form.
public ActionResult BookUser()
{
//Gather required variables
ApplicationUser user = db.Users.First(i => i.UserName == User.Identity.Name);
int classID = int.Parse(Request.Form["classID"]);
using (db)
{
var editedLesson = db.Lessons.Single(s => s.LessonID == classID);
db.Lessons.Attach(editedLesson);
var editedUser = db.Users.Single(s => s.Id == user.Id);
db.Users.Attach(editedUser);
editedLesson.Students.Add(editedUser);
db.SaveChanges();
}
return View("Index");
When I try and run it, when i press my book button, it runs through the code and executes. checking the database it has indeed inserted the key values into the pivot table. When i load the model of the lesson to view its details, the Student attribute has a count of 0. I've been at this for days and i've got the feeling i'm missing something kickself simple....but i've gone over it a dozen times and can't see what i'm doing wrong...
Mark your lists with virtual to enable lazy loading. Also is not required to initialize the lists Lessons = new List<Lesson>();

ASP MVC Application User Null using User.Identity.GetUserId

Ok so I have a relationship between the ApplicationUser and QuestionResults, my models are as below, the userId nor the UserName is retrieved, but I really need the UserId setup as a foreignKey on the QuestionResults entity.
Any help is much appreciated the error that I am receiving is as below:
An exception of type 'System.NullReferenceException' occurred in STRA.dll but was not handled in user code
Additional information: Object reference not set to an instance of an object.
on these lines of code:
qr.User.Id = User.Identity.GetUserId();
qr.User.UserName = User.Identity.GetUserName();
Models
public class QuestionResult
{
public QuestionResult()
{
DateCreated = DateTime.Now;
DateModified = DateTime.Now;
}
public int Id { get; set; }
public DateTime? DateCreated { get; set; }
public DateTime? DateModified { get; set; }
public int QuestionScore { get; set; }
//navigation properties
public virtual ApplicationUser User { get; set; }
//public ICollection<CategoryResult> CategoryResult { get; set; }
//public virtual Category Category { get; set; }
[NotMapped]
public int CategoryId { get; set; }
public virtual Question Question { get; set; }
public int QuestionId { get; set; }
//public virtual Category Category { get; set; }
//public int CategoryId { get; set; }
}
public class ApplicationUser : IdentityUser
{
public string FirstName { get; set; }
public string Surname { get; set; }
public string Industry { get; set; }
public string GlobalRegion { get; set; }
public string CurrentSituation { get; set; }
public int SalesForceSize { get; set; }
public bool IsVerified { get; set; }
//navigation properties
public virtual ICollection<CategoryResult> CategoryResult { get; set; }
public virtual ICollection<QuestionResult> QuestionResult { get; set; }
//public virtual ICollection<Report> Report { get; set; }
//public virtual ICollection<SurveyResult> SurveyResult { get; set; }
public virtual Organisation Organisation { get; set; }
public int? OrganisationId { get; set; }
public async Task<ClaimsIdentity> GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
{
// Note the authenticationType must match the one defined in CookieAuthenticationOptions.AuthenticationType
var userIdentity = await manager.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
// Add custom user claims here
return userIdentity;
}
}
Your code is equivalent to this::
var user = qr.User;
user.Id = User.Identity.GetUserId();
If the QuestionResult was already linked to a User then you would not be changing which User is linked to the QuestionResult, you would be changing the Id of an existing User - and that is not allowed anyway.
But the QuestionResult is not already linked to a User. qr.User is null - so you get a null reference exception.
In general, life is much easier in Entity Framework if you add the foreign key to your model:
public class QuestionResult
{
public string UserId { get; set; }
public virtual ApplicationUser User { get; set; }
}
And now you can set the foreign key directly:
qr.UserId = User.Identity.GetUserId();
References:
Why does Entity Framework Reinsert Existing Objects into My Database?
Making Do with Absent Foreign Keys
So, do you wanna make foreing key for userid?
You can do like that:
public int UserRefID { get; set; }
[ForeignKey("UserRefID")]
public xxx UserID { get; set; } //data name like ApplicationUser
And this error appear coz you have some problem about models or data classes.
Set it as a string
Model:
public ApplicationUser User { get; set; }
public string UserId { get; set; }
Controller:
qr.UserId = User.Identity.GetUserId();
And worked perfectly, even created foreign keys, that easy. Thanks so much!

Entity Framework One-To-Many issue

I use Entity Framework in my project. I stuck in some trouble.
I have two classes. Here are they:
public class User
{
public virtual Guid Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual string Username { get; set; }
public string Email { get; set; }
public virtual Company Company { get; set; }
}
public class Company
{
public Guid Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public string Requisites { get; set; }
public virtual List<User> Workers { get; set; }
}
Also I have repo. So when I create a new user and I want to add this user to company.
How should I implement that? I have two ways:
user.Company = company;
company.Workers.Add(user);
Which way is preferable?
If company is already attached to the context.
Either
var company = db.Set<Company>().Find(companyId);
or
db.Set<Company>().Attach(company);
user.Company = company;
In the first case, if you only do that. The user will not be added to the database, you need to have this too.
db.Entry(user).State = EntityState.Added;
or
db.Set<User>().Add(user);
Then user will be added and will have relationship with company.
company.Workers.Add(user);
This one only should be okay, the user will be added and have relationship with company. But be careful if Workers is null, you need to instantiate it first.

Code First EF relationship duplicate

I have a working model, but have noticed that the relationship has been created twice in the database. Originally, it created two columns in the table, but with the addition of a specified foreign key attribute it has now just the one.
I have an Account class, which has many employers who can use the account. (one to many) Here are the classes:
public class Account
{
public int AccountId { get; set; }
[Required(ErrorMessage = Constants.ValidationMessages.FieldRequired)]
public string Name { get; set; }
public int? PrimaryUserId { get; set; }
[ForeignKey("PrimaryUserId")]
public Employer PrimaryUser { get; set; }
[ForeignKey("EmpAccountId")]
public ICollection<Employer> Employers { get; set; }
}
here is the inherited Employer class
public class Employer : User
{
public Employer()
{
DepartmentsToPost = new Collection<Department>();
Contacts = new Collection<Contact>();
}
[Display(Name = "Workplaces to advertise jobs")]
public virtual ICollection<Department> DepartmentsToPost { get; set; }
public int EmpAccountId { get; set; }
[ForeignKey("EmpAccountId")]
public virtual Account Account { get; set; }
public override string UserType
{
get { return "Employer"; }
}
}
User Table:
UserId
Username
FirstName
Surname
EmpAccountId
Discriminator
Account Table
AccountId
Name
PrimaryUserId
There is one link back to the User table - this is for the PrimaryUser field, and this is correct. There are two other relationships: Account -> Employers. EF has named them Account_Employers and Employer_Account. These are duplicates.
How can I prevent this occuring?
The Employers collection should be decorated with InversePropertyAttribute to point to the navigational property on the other side.
public class Account
{
public int AccountId { get; set; }
[Required(ErrorMessage = Constants.ValidationMessages.FieldRequired)]
public string Name { get; set; }
public int? PrimaryUserId { get; set; }
[ForeignKey("PrimaryUserId")]
public Employer PrimaryUser { get; set; }
[InverseProperty("Account")]
public ICollection<Employer> Employers { get; set; }
}

Updating foreign key entities in Entity Framework 4.1

I'm currently building a REST service using WebApi and the backing store is using EF4.1. I've run into a snag whereby I cannot update the foreign key...
The 2 model classes look like:
public class User
{
[Key]
public int UserId { get; set; }
public string Name { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Gender { get; set; }
//
// Membership
public Membership Membership { get; set; }
}
public class Membership: Base
{
[Key]
public int MembershipId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public decimal Price { get; set; }
public virtual Collection<User> Users { get; set; }
}
My application populates both the User object and the Membership object and passes them both to the following Update method:
public User Update(User entity)
{
if(entity.Membership != null)
dbContext.Memberships.Attach(entity.Membership);
dbContext.Entry(entity).State = EntityState.Modified;
dbContext.SaveChanges();
}
I've confirmed that both objects are present at the point of updating, but the membership foreign key is never persisted to the database. I'm certain I'm doing something simple wrong. Any insight would be greatly appreciated.
Thanks.

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