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Which one is the correct one-to-many relation in EF

i am designing a system and one of my entity has one to many relation as shown below.
public class Product
{
public int Id { get; set; }
}
public class CompetitorProduct
{
public int Id { get; set; }
public Product Product { get; set; }
}
competitorProduct indicates that product has a equivalent which is sold by different store. should i define one-to-many relation as shown above or below? which one is correct?
public class Product
{
public int Id { get; set; }
public virtual ICollection<CompetitorProduct> CompetitorProducts{ get; set; }
}
public class CompetitorProduct
{
public int Id { get; set; }
}

Assuming it is a one to many relationship (what would happen if a competitor product was competing with more than one of your products for example) you can do both and add in a foreign key as well.
public class Product
{
public int Id { get; set; }
public virtual ICollection<CompetitorProduct> CompetitorProducts { get; set; }
}
public class CompetitorProduct
{
public int Id { get; set; }
public int ProductId { get; set; }
public virtual Product Product { get; set; }
}
You can then set up your relationship using fluent API as so:
modelBuilder.Entity<CompetitorProduct>(entity =>
{
entity.HasOne(e => e.Product)
.WithMany(e => e.CompetitorProducts)
.HasForeignKey(e => e.ProductId)
.HasConstraintName("FK_ComptetitorProduct_Product");
});
This way you can access the competitor products from the product and the product from the competitor products.

Here is a quick example of a ecommerce site I have worked on and how we did table relations.
I removed a bunch of the fields so you can see what you really need. Once to make relations and run Add-Migration EF will handle the FK constraints for you as long as you identified them in models like how I have below.
public class ApplicationUser : IdentityUser
{
public ApplicationUser()
{
Active = true;
CreateDateTimeUtc = DateTime.UtcNow;
ModifiedDateTimeUtc = DateTime.UtcNow;
}
[StringLength(500)]
public string FirstName { get; set; }
[StringLength(500)]
public string LastName { get; set; }
[StringLength(1000)]
public string Address { get; set; }
[StringLength(100)]
public string Unit { get; set; }
[StringLength(250)]
public string City { get; set; }
[StringLength(25)]
public string State { get; set; }
[StringLength(20)]
public string ZipCode { get; set; }
//This will give access to a list of child carts a user could have
[Index]
public bool Active { get; set; }
public virtual ICollection<Cart> Carts { get; set; }
// Account Profile Image
public byte[] ProfileImage { get; set; }
[StringLength(500)]
public string ProfileFilename { get; set; }
[StringLength(100)]
public string ProfileMimeType { get; set; }
}
[Table("Cart", Schema = "dbo")]
public class Cart : AbstractTable
{
public Cart()
{
IsComplete = false;
}
//This create relation to user table where I can get one unique user.
[StringLength(128)]
[ForeignKey("ApplicationUser")]
public string UserId { get; set; }
public virtual ApplicationUser ApplicationUser { get; set; }
//These link us to child tables of Cart where we can get a LIST of the items below
public virtual ICollection<CartCategory> CartCategories { get; set; }
public virtual ICollection<CartItem> CartItems { get; set; }
// Marked when a payment/receipt is generated based off of this cart
public bool IsComplete { get; set; }
}
[Table("CartItem", Schema = "dbo")]
public class CartItem : AbstractTable
{
//This will return one unique cart id and let us access it as the parent record
[ForeignKey("Cart")]
public Guid CartId { get; set; }
public virtual Cart Cart { get; set; }
// Signifies if this was paid for in a receipt
public bool IsComplete { get; set; }
public virtual ICollection<CartItemCustomField> CustomFields { get; set; }
}

How add identity and user management into aspnetcore web api?

I'm building asp.net core web api with 3 types of users: Admin, Clients and Programmers. Each of those roles have their own list of tickets. These are entity classes I've already added:
public class User
{
[Key]
public Guid Id { get; set; }
[Required]
[MaxLength(50)]
public string FirstName { get; set; }
[Required]
[MaxLength(50)]
public string LastName { get; set; }
[Required]
public string Address { get; set; }
[Required]
public string Zip { get; set; }
[Required]
[Phone]
public string PhoneNumber { get; set; }
[Required]
[EmailAddress]
public string EmailAddress { get; set; }
[Required]
public Gender Gender { get; set; }
[Required]
[MaxLength(50)]
public string UserName { get; set; }
[Required]
[MaxLength(50)]
public string Password { get; set; }
[Required]
public Role Role { get; set; }
public virtual Programmer Programmer { get; set; }
public virtual Admin Admin { get; set; }
public virtual Client Client { get; set; }
}
public class Client
{
public Guid clientId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual ICollection<Ticket> Tickets { get; set; } = new List<Ticket>();
public Guid Id { get; set; }
public virtual User User { get; set; }
}
public class Admin
{
public Guid adminId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public virtual ICollection<Ticket> Tickets { get; set; } = new List<Ticket>();
public Guid Id { get; set; }
public virtual User User { get; set; }
}
public class Programmer
{
public Guid programmerId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public ProgrammingLanguage ProgrammingLanguage { get; set; }
public Experience Experience { get; set; }
public DetailOriented DetailOriented { get; set; }
public FieldOfInterest FieldOfInterest { get; set; }
public virtual ICollection<Ticket> Tickets { get; set; } = new List<Ticket>();
public Guid Id { get; set; }
public virtual User User { get; set; }
}
I've already created regular DbContext and implemented functionality of my api using that DbContext. Now I want to change users to be IdentityUsers. I'm not sure should I make a new project where UserIdentity will be handled and then pass those users to my api(if so, how can I pass them to api and connect them with their tickets, i.e.do I leave only tickets table in api?) or make users as part of an api as I already did(if so, what would be the best way to change them into identity users so that I can query their tickets later?). Does anyone have any tips/links/similar code samples or something? I would be grateful :)

Out of the box, Identity supports a single set of user profile properties. The easiest solution would be to create an AppUser class that inherits from IdentityUser with ALL of the properties across your user types. Also introduce an interface for each of your user types with the properties they support.
class AppUser: IdentityUser, IAdmin, IProgrammmer, IClient {...}
Based on the IdentityRole associated with the user, you can cast the AppUser instance to the appropriate interface to access the user-specific properties.

Entity Framework many to many to single object

I am trying to map a property on a user that that has a many to many relationship in the database but there is only ever one per user. But I am unable to figure out the required map in entityframework. I have the following entities:
public class User
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
//Need to map this property
public virtual SecurityRole SecurityRole { get; set; }
}
public class SecurityRole
{
public int Id { get; set; }
public string Name { get; set; }
}
An the following tables:
User:
Id
FirstName
LastName
SecurityRole:
Id
Name
UserSecurityRole:
UserId
SecurityRoleId
If anyone has any idea or could point me in the right direction that would be great

Even if there is only one record in the database, if you have a many to many relationship between User and SecurityRole it should work like this:
public class User
{
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public List<SecurityRole> SecurityRoles { get; set; }
}
public class SecurityRole
{
public int Id { get; set; }
public string Name { get; set; }
public List<User> Users { get; set; }
}

EF code Model for e-tender system in MVC4

Am building tender board Application am getting some confusing in how structure my model using >> entity-framework in >> MVC4
Here the descriptions:
In my simple membership Role Table , I have:
(Admin,Tender,Provider,Member)
Administration: he have right to change normal user role from “Member” to “Provider and prove winner bidder after tender organization approved.
Suppliers: Normal users will be assigning as “member” and will be activated by Administration to be provider and then they can bid any projects they want.
Projects: created by Tender Organization Users every project has many requirements
Requirement: each one related to project.
Tenders: Here my problem actually Tender are “Ministries in country and have to be set in system” but each ministry obvious have many users “Manager, let say 5 in each” who will vote for supplier.Mangers can vote to only those suppliers which are laid under the same ministry.
Do I miss others tables?
Also I don’t really know how to structure all the tables with relations and also with (UserprofileTbale, and Role Table):
Here my try, help me on that.
My DBContext:
public class ProjectContext : DbContext
{
public ProjectContext()
: base("OTMSProjects")
{
}
public DbSet<ProjectEntry> Entries { get; set; }
public DbSet<Requiernments> RequiernmentEntries { get; set; }
public DbSet<Supplier> Suppliers { get; set; }
public DbSet<Tender> Tenders { get; set; }
public DbSet<UserProfile> UserProfiles { get; set; }
//public DbSet<UserRoles> UserRoles { get; set; } // do I have to set this too?
}}
My tables:
public class ProjectEntry
{
[Key]
public int ID { get; set; }
[Required]
public string ProjectName { get; set; }
public string Description { get; set; }
public string Statue {get; set; }
public string UplodedFiles { get; set; }
public string Budget { get; set; }
public string EstimateTime { get; set; }
public string Criterias { get; set; }
public DateTime? DueDate { get; set; }
// Relations with others tables
public virtual Tender Tender { get; set; }// every project have only one tender
public virtual ICollection<Supplier> Suppliers { get; set; } // every project have one or more supplier
public virtual ICollection<Requiernments> Requirements { get; set; }
}
........
public class Requiernments
{
[Key]
public int RequiernmentId { get; set; }
public int ID { get; set; }
public string RequiernmentName { get; set; }
public string RequiernmentType { get; set; }
public string RequiernmentPrioritet { get; set; }
public float RequiernmenWhight { get; set; }
public string ProviderAnswer { get; set; }
public string ProviderComments{ get; set; }
public virtual ProjectEntry Projects { get; set; }
}
........
public class Supplier
{
[Key]
public int SupplierId { get; set; }
public int ID { get; set; }
public int SupplierName { get; set; }
public int SupplierCat { get; set; }
public virtual ICollection<ProjectEntry> Projects { get; set; }
}
......
public class Tender
{
[Key]
public int TenderId { get; set; }
public string TenderName { get; set; }
public string TenderMinstry{ get; set; }
public int ID { get; set; }//link to project
public int UserId { get; set; } //this links to the userid in the UserProfiles table
public virtual ICollection<ProjectEntry> Projects { get; set; }
//public virtual ICollection<UserProfile> Userprofile { get; set; }
public virtual UserProfile UserProfile { get; set; }
}
My membership table in my AccountModel created by defualt in Mvc4 ( I only add the RoleTable :
[Table("UserProfile")]
public class UserProfile
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int UserId { get; set; }
public string UserName { get; set; }
public string EmailAddress { get; set; }
public ICollection<UserRoles> UserRoles { get; set; }
}
[Table("webpages_Roles")]
public class UserRoles
{
[Key]
public int RoleId { get; set; }
public string RoleName { get; set; }
[ForeignKey("UserId")]
public ICollection<UserProfile> UserProfiles { get; set; }
}
Am not sure also about how to link the Userprofile with Tender Table and supplier Table?

Not sure what you are missed or not. but as per database creation you must follow your business logic and normalization rules.
Some of my suggestions are here:
1. ProjectEntry
here you should create a Status Table separately and gives its reference key as StatusID into the ProjectEntry table.
Requirement
you should create Requirement Priority and Type tables are separately.
Add separate table for provider question and answers. I hope you need to store more than one question answers for single requirement.
Supplier
Add Separate Table for Supplier category
Tender
Create Tender Ministry table separately and give its reference to the tender table.
you should make a table for Uploaded files as Documents. It should contains ID, ProjectId, Documentname, DocumentType, DocumentShortDescription, uplodatedDateTime fields.

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; }
}