/// <summary>
        /// Gets all categories in database
        /// </summary>
        /// <returns>List of categories</returns>
        public override List<Res> FillRess()
        {
            List<Res> infos = new List<Res>();
            string connString = ConfigurationManager.ConnectionStrings[connStringName].ConnectionString;
            string providerName = ConfigurationManager.ConnectionStrings[connStringName].ProviderName;
            DbProviderFactory provider = DbProviderFactories.GetFactory(providerName);

            using (DbConnection conn = provider.CreateConnection())
            {
                conn.ConnectionString = connString;

                using (DbCommand cmd = conn.CreateCommand())
                {
                    string sqlQuery = "SELECT ResID,FileName,ResType,Description,Author,IsPublished,DateCreated,Points " +
                        "FROM " + tablePrefix + "Res ";
                    cmd.CommandText = sqlQuery;
                    cmd.CommandType = CommandType.Text;
                    conn.Open();

                    using (DbDataReader rdr = cmd.ExecuteReader())
                    {
                        if (rdr.HasRows)
                        {
                            while (rdr.Read())
                            {
                                Res inf = new Res();
                                inf.Id = new Guid(rdr.GetGuid(0).ToString());
                                inf.FileName = rdr.GetString(1);
                                inf.ResType = rdr.GetString(2);
                                inf.Description = rdr.GetString(3);
                                inf.Author = rdr.GetString(4);
                                inf.IsPublished = rdr.GetBoolean(5);
                                inf.DateCreated = rdr.GetDateTime(6);
                                inf.Points = rdr.GetInt32(7);
                                infos.Add(inf);
                                inf.MarkOld();
                            }
                        }
                    }
                }
            }

            return infos;
        }
        /// <summary>
        /// Returns a field 
        /// </summary>
        /// <param name="id">Id of field to return</param>
        /// <returns></returns>
        public override Res SelectRes(Guid id)
        {
            List<Res> Ress = Res.Ress;

            Res res = new Res();

            foreach (Res cat in Ress)
            {
                if (cat.Id == id)
                    res = cat;
            }
            res.MarkOld();
            return res;
        }