Employee.cs

using System;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace GraphQLSampleApp.DataAccess.Entity
{
    public class Employee
    {
        [Key]
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]       
        public int EmployeeId { get; set; }

        [Required]
        public string Name { get; set; }

        [Required]
        [EmailAddress]
        public string Email { get; set; }

        [Required]
        [Range(minimum: 20, maximum: 50)]
        public int Age { get; set; }

        public int DepartmentId { get; set; }
        public Department Department { get; set; }
    }
}