public void Insert(User user)
 {
     using (SqlConnection connection = new SqlConnection(_connectionString))
     {
         connection.Open();
         using (SqlCommand command = new SqlCommand())
         {
             command.Connection  = connection;
             command.CommandType = System.Data.CommandType.StoredProcedure;
             command.CommandText = USER_INSERT;
             SqlParameter[] parameters =
             {
                 new SqlParameter("@MedicalPersonnelId", user.GetMedicalPersonnaleId()),
                 new SqlParameter("Password",            user.GetPassword()),
                 new SqlParameter("Username",            user.username)
             };
             command.Parameters.AddRange(parameters);
             command.ExecuteNonQuery();
         }
     }
 }