This article will demonstrate how to implement primary key and foreign key relationship in Code First approach in Entity Framework.

To complete this task, I am going to create Employee and Department Model Class and let’s see how to make relationship. Following are the two model class. 

public class Department  
{  
   [Key]  
   public int DepartmentId { get; set; }  
  
   [Required]  
   public string DepartmentName { get; set; }  
}  
  
public class Employee  
{  
   [Key]  
   public int EmployeeId { get; set; }  
  
   [Required]  
   public string EmployeeName { get; set; }  
  
}

 

Department Model has primary key as DepartmentId and Employee Model has primary key as EmployeeId. I am going to create a foreign key of DepartmentId in Employee Model.

public class Department  
{  
   [Key]  
   public int DepartmentId { get; set; }  
  
   [Required]  
   public string DepartmentName { get; set; }  
}  
  
public class Employee  
{  
   [Key]  
   public int EmployeeId { get; set; }  
  
   [Required]  
   public string EmployeeName { get; set; }  
  
   // Foreign key   
   [Display(Name = "Department")]  
   public virtual int DepartmentId { get; set; }  
  
   [ForeignKey("DepartmentId")]  
   public virtual Department Departments { get; set; }  
}

 

To create Foreign Key, you need to use ForeignKey attribute with specifying the name of the property as parameter. 

[ForeignKey("DepartmentId")]  
public virtual Department Departments { get; set; }

 

You also need to specify the name of the table which is going to participate in relationship. I mean to say, define the foreign key table.

[Display(Name = "Department")]  
public virtual int DepartmentId { get; set; }

 

Thanks for reading this article, hope you enjoyed it.