我有两个班级联系人和组
结合FirstName和LastName必须是唯一的，可以为单个联系人添加多个地址。如何在实体框架代码优先方法中做到这一点？
public class Contacts
{
[Key]
public int ContactID { get; set; }
[ForeignKey("Group")]
public int GroupID { get; set; }
[Required]
public string FirstName { get; set; }
[Required]
public string LastName { get; set; }
[Required]
public string Address { get; set; }
[Required]
public string Number { get; set; }
[Required]
[EmailAddress]
public string EmailId { get; set; }
[DataType(DataType.Date)]
public DateTime CreateDate { get; set; }
public DateTime? ModifiedDate { get; set; }
public virtual Groups Group { get; set; }
}
public class Groups
{
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int GroupID { get; set; }
[Required]
public string GroupName { get; set; }
[Required]
public string GroupDiscription { get; set; }
public DateTime CreateDate { get; set; }
public DateTime ModifiedDate { get; set; }
}