//here is my data models:
public class People
{
public int PeopleID { get; set; }
[Required]
public string Name { get; set; }
}
[Table("User")]
public class User : People
{
[Required]
public string LoginName { get; set; }
[Required]
public string PassWord { get; set; }
}
//and i stored an item into the People table
context.People.Add(new People { Name = "Jack" });
context.SaveChanges();
//and now "Jack" is promoted as an user of this system
//how can I update his data and let him has is LoginName and Password?
This is a common design mistake.
Objects can't change their type; you shouldn't be using inheritance in this case.
Instead, the User can have a reference to a Person (another hint: your entity names should be singular, regardless of what you name the table)
First of all you need to declare discriminator column. For example PeopleType which couln't discriminate users from all peolple by specific value.
So in your scenatio you will need to create Jack as User but you could assecc it as item of people
[Table("People")]
public class People
{
public int PeopleID { get; set; }
[Required]
public string Name { get; set; }
public int Type { get; set; }
}
public class User : People
{
[Required]
public string LoginName { get; set; }
[Required]
public string PassWord { get; set; }
}
Overide it in DbContext
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<People>().Map<User>(m => { m.Requires("PoepleType").HasValue(1 /* any value you like */); })
}
Related
I am trying to make a simple website that tracks students, programs, and classes. I've created the entities and I'm getting an error when trying to add the migration.
"The entity type 'Program' requires a primary key to be defined."
I have tried using the [Key] attribute and there is an Id field. The other table was created just fine. What else should I try?
Here is the problem class:
public class Program
{
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool UseRanks { get; set; }
}
Here is another table that I had no problems creating a migration for:
public class Person
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string CellPhone { get; set; }
public string HomePhone { get; set; }
public string WorkPhone { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string ZipCode { get; set; }
public DateTime BirthDate { get; set; }
}
Here is what is in my ApplicationDbContext class:
public class ApplicationDbContext : IdentityDbContext
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
: base(options)
{
}
//public DbSet<Attendance> Attendances { get; set; }
public DbSet<Person> People { get; set; }
public DbSet<Bill> Bills { get; set; }
//public DbSet<Session> Sessions { get; set; }
public DbSet<Program> Programs { get; set; }
}
I've commented out the other entities because I was trying to add them one at a time. Trying to add a migration with all the entities resulted in the same error with the same specific class.
Complete shot in the dark, but based on the name of this class, I'm guessing you're referencing the wrong Program. Make sure that your DbSet<Program> is actually using your Program entity and not something like the Program class used at the console app level. You'll likely need to explicitly use the namespace, i.e. DbSet<MyApp.Models.Program>.
You might also consider changing the name of the class to remove any chance of ambiguity. There's some class names that are just going to wreck havoc trying to use them because they'll conflict with framework stuff constantly. It's usually more hassle than it's worth just to have that particular name. Program is one of those.
You can try to use this way:
public class Program
{
[Key]
public int Id { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool UseRanks { get; set; }
}
Adding [Key] attribute to the Id property.
In the file ApplicationDbContext.cs, you can override OnModelCreating method:
public DbSet<Program> Programs { get; set; }
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
builder.Entity<Program>().ToTable("Programs").HasKey(x => x.Id);
}
I have CodeFirst design like this:
public class Email
{
public string Address { get; set; }
public Company Company { get; set; }
public int? CompanyId { get; set; }
public User User { get; set; }
public int? UserId { get; set; }
//many other props
}
public class Company
{
public List<Email> Emails { get; set; }
}
public class User
{
public List<Email> Emails { get; set; }
}
In a good way, Email can belong to only one foreign key: CompanyId or UserId. But now it allows CompanyId and UserId. It's wrong. Anyway, that design with nullables is ugly. For example, to get all emails linked to companies I need do this:
var companyEmails = _context.Emails.Where(x => x.CompanyId.HasValue);
I feel there is a better approach to define multiply foreign keys with OR logic. Please, help me find a way.
If you want to have the only one reference to Company or User, that mean it will not be FK and also you should have additional field with description, to which table this field points.
Alternatively, you can try Table per Hierarchy approach. At this case database table will remain almost the same, only new Discriminator column will be implicitly added, to distinguish classes, but you will can to write more "elegant" code:
public abstract class Email
{
public string Address { get; set; }
}
public class CompanyEmail : Email
{
public Company Company { get; set; }
public int? CompanyId { get; set; }
}
public class UserEmail : BaseEmail
{
public User User { get; set; }
public int? UserId { get; set; }
}
Usage:
var companyEmails = _context.Emails.OfType<CompanyEmail>();
//underlying query:
//select * from dbo.Emails where Discriminator = 'CompanyEmail'
I am getting this error in my .Net MVC 4 web application:
The property 'Username' 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<T> where T is a valid entity type.
I am very new to Entity Framework and I can't seem to get around this issue. Here is some code:
//DB Context
public class EFDbContext : DbContext
{
public DbSet<User> Users { get; set; }
public DbSet<Role> Roles { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<User>().HasMany(u => u.Roles).WithMany(r => r.Users).Map(x => x.MapLeftKey("Username").MapRightKey("RoleName").ToTable("Users_Roles"));
}
}
//Entity Classes
public class User
{
[Key]
public string Username { get; set; }
public string Password { get; set; }
public string Email { get; set; }
public string Comment { get; set; }
public int Level { get; set; }
public string PasswordQuestion { get; set; }
public string PasswordAnswer { get; set; }
public bool IsApproved { get; set; }
public DateTime LastActivityDate { get; set; }
public DateTime LastLoginDate { get; set; }
public DateTime LastPasswordChangedDate { get; set; }
public DateTime CreationDate { get; set; }
public bool IsOnLine { get; set; }
public bool IsLockedOut { get; set; }
public DateTime LastLockedOutDate { get; set; }
public int FailedPasswordAttemptCount { get; set; }
public DateTime FailedPasswordAttemptWindowStart { get; set; }
public int FailedPasswordAnswerAttemptCount { get; set; }
public DateTime FailedPasswordAnswerAttemptWindowStart { get; set; }
[InverseProperty("RoleName")]
public virtual ICollection<Role> Roles { get; set; }
public override string ToString()
{
return this.Username;
}
}
public class Role
{
[Key]
public string RoleName { get; set; }
public int Level { get; set; }
[InverseProperty("Username")]
public virtual ICollection<User> Users { get; set; }
public override string ToString()
{
return this.RoleName;
}
}
//Repository
public class EFUsersRepository : IUsersRepository
{
private EFDbContext context = new EFDbContext();
public IQueryable<User> Users
{
get { return context.Users; }
}
public User GetUser(string username)
{
return context.Users.Find(username); //THIS IS WHERE THE CRASH OCCURS
}
}
//DB Setup
Table Users, Role and Users_Role. Users_Role is a simple linking table with [username, role] columns both of type varchar.
The database tables columns & types match the two classes above (User,Role).
I inherited this project which was unfinished but I can't get it to run successfully. Any help understanding what the issue is would be helpful. Thanks!
It might be that Entity Framework is updated. Easiest way will be to recreate the DataModel.
Even if the previous programmer did not use Entity Data Mode, you can at least copy the auto generated code such as EFDbContext, Users and Roles classes.
It turns out, after commenting out enough items all day long, the the following lines are what caused this error for me:
[InverseProperty("RoleName")] //In file User.cs (as shown above)
[InverseProperty("UserName")] //in file Role.cs (as shown above)
I am still learning Entity Framework and I don't know why this was the solution, but it stopped the error which I reported above.
I hope that this helps someone else and if anyone wants to help me understand what the issue was in detail, please feel free. I am eager to learn.
I have two tables (Table A, Table B) joined with a join table (TableAB) with 3 payload columns. By Payload I mean columns apart from Id, TableAId, and TableBId.
I can insert into all tables successfully, but I need to insert data into one of the payload columns on Insert. I'm using EF 4.3, Fluent API. Can anyone help? Thanks in advance.
public class Organisation : EntityBase<int>, IAggregateRoot
{
public string Name { get; set; }
public string Url { get; set; }
public int CountryId { get; set; }
public int? OwnershipTypeId { get; set; }
public int OrganisationStatusId { get; set; }
public virtual ICollection<Feature> Features { get; set; }
public virtual ICollection<OrganisationType> OrganisationTypes { get; set; }
public virtual ICollection<PricePlan> PricePlans { get; set; }
public virtual ICollection<User> Users { get; set; }
}
public class User: EntityBase<Guid>, IAggregateRoot
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string JobTitle { get; set; }
public int? PhoneCallingCodeId { get; set; }
public int? PhoneAreaCode{ get; set; }
public string PhoneLocal { get; set; }
public int? MobileCallingCodeId { get; set; }
public int? MobileAreaCode { get; set; }
public string MobileLocal { get; set; }
public virtual ICollection<Organisation.Organisation> Organisations { get; set; }
}
public class OrganisationUser : EntityBase<int>, IAggregateRoot
{
public DateTime StartDate { get; set; }
public DateTime? EndDate { get; set; }
public int OrganisationRoleId {get; set;}//Foreign Key - have tried leaving it out, tried it as public virtual Organisation Organisation {get;set;
public bool IsApproved { get; set; }
}
public class SDContext : DbContext
{
public ObjectContext Core
{
get
{
return (this as IObjectContextAdapter).ObjectContext;
}
}
public IDbSet<User> User { get; set; }
public IDbSet<Organisation> Organisation { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Conventions.Remove<PluralizingTableNameConvention>();
modelBuilder.Entity<Organisation>().HasMany(u => u.Users).WithMany(o => o.Organisations).Map(m =>
{
m.MapLeftKey("OrganisationId");
m.MapRightKey("UserId");
m.ToTable("OrganisationUser");
});
//I have tried specifically defining the foreign key in fluent, but I really need to understand how I can add the payload properties once I access and edit them.
Your mapping is not correct for your purpose. If you want to treat OrganisationUser as an intermediate entity between Organisation and User you must create relationships between Organisation and OrganisationUser and between User and OrganisationUser, not directly between Organisation and User.
Because of the intermediate entity which contains its own scalar properties you cannot create a many-to-many mapping. EF does not support many-to-many relationships with "payload". You need two one-to-many relationships:
public class Organisation : EntityBase<int>, IAggregateRoot
{
// ...
// this replaces the Users collection
public virtual ICollection<OrganisationUser> OrganisationUsers { get; set; }
}
public class User : EntityBase<Guid>, IAggregateRoot
{
// ...
// this replaces the Organisations collection
public virtual ICollection<OrganisationUser> OrganisationUsers { get; set; }
}
public class OrganisationUser : EntityBase<int>, IAggregateRoot
{
public int OrganisationId { get; set; }
public Organisation Organisation { get; set; }
public Guid UserId { get; set; }
public User User { get; set; }
// ... "payload" properties ...
}
In Fluent API you must replace the many-to-many mapping by the following:
modelBuilder.Entity<Organisation>()
.HasMany(o => o.OrganisationUsers)
.WithRequired(ou => ou.Organisation)
.HasForeignKey(ou => ou.OrganisationId);
modelBuilder.Entity<User>()
.HasMany(u => u.OrganisationUsers)
.WithRequired(ou => ou.User)
.HasForeignKey(ou => ou.UserId);
Your derived DbContext may also contain a separate set for the OrganisationUser entity:
public IDbSet<OrganisationUser> OrganisationUsers { get; set; }
It's obvious now how you write something into the intermediate table:
var newOrganisationUser = new OrganisastionUser
{
OrganisationId = 5,
UserId = 8,
SomePayLoadProperty = someValue,
// ...
};
context.OrganisastionUsers.Add(newOrganisastionUser);
context.SaveChanges();
If you want to make sure that each pair of OrganisationId and UserId can only exist once in the link table, it would be better to make a composite primary key of those two columns to ensure uniqueness in the database instead of using a separate Id. In Fluent API it would be:
modelBuilder.Entity<OrganisationUser>()
.HasKey(ou => new { ou.OrganisationId, ou.UserId });
More details about such a type of model and how to work with it is here:
Create code first, many to many, with additional fields in association table
Below are my domain entities
public class User
{
public int Id { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
public DateTime? DateOfBirth { get; set; }
public string Username { get; set; }
public string Password { get; set; }
public string EmailAddress { get; set; }
public RoleType RoleType { get; set; }
}
public class Role
{
public int Id { get; set; }
public string Name { get; set; }
}
I have made RoleType as a complex type (to acheive enum mapping). So I could use something like context.Users.FirstOrDefault(u => u.RoleType.Value == (long)RoleTypes.Admin)
RoleTypes.Admin is an enum mapping to the Role entity
public class RoleType
{
public int Value { get; set; }
// And all the implicit operators to map with enum
}
And then I have created a mapping using fluent api
public class RoleTypeMapping : ComplexTypeConfiguration<RoleType>
{
public RoleTypeMapping()
{
Property(r => r.Value)
.HasColumnName("RoleId"); // To make sure that in RoleType property of User EF entity maps to an int column [RoleId] in database (table [Users])
}
}
Using fluent-api, I want to create a foreign key association in [Users] table for [Users].[RoleId] referencing [Role].[Id]. Please can anyone provide me guidance to acheive this
I tired adding a property of type Role and creating a mapping through fluent-api, but EF creates another column Role_Id and makes it the foreign key. I want the existing [RoleId] column (complex type) to be the foreign key
It is not possible. If you want to have association with Role table you must abandon your enum-like approach and define Users entity like:
public class User
{
public int Id { get; set; }
public string Firstname { get; set; }
public string Lastname { get; set; }
public DateTime? DateOfBirth { get; set; }
public string Username { get; set; }
public string Password { get; set; }
public string EmailAddress { get; set; }
public Role Role { get; set; }
}
First of all relations are not enums and complex types cannot contain navigation properties (as well as foreign keys).