/// <summary>
        /// Gets all categories in database
        /// </summary>
        /// <returns>List of categories</returns>
        public override List<Field> FillFields()
        {
            List<Field> fields = new List<Field>();
            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 FieldID,FieldName,Description " +
                        "FROM " + tablePrefix + "Fields ";
                    cmd.CommandText = sqlQuery;
                    cmd.CommandType = CommandType.Text;
                    conn.Open();

                    using (DbDataReader rdr = cmd.ExecuteReader())
                    {
                        if (rdr.HasRows)
                        {
                            while (rdr.Read())
                            {
                                Field fld = new Field();
                                fld.FieldName = rdr.GetString(1);
                                if (rdr.IsDBNull(2))
                                    fld.Description = "";
                                else
                                    fld.Description = rdr.GetString(2);

                                fld.Id = new Guid(rdr.GetGuid(0).ToString());
                                fields.Add(fld);
                                fld.MarkOld();
                            }
                        }
                    }
                }
            }

            return fields;
        }
        /// <summary>
        /// Returns a field 
        /// </summary>
        /// <param name="id">Id of field to return</param>
        /// <returns></returns>
        public override Field SelectField(Guid id)
        {
            List<Field> fields = Field.Fields;

            Field field = new Field();

            foreach (Field cat in fields)
            {
                if (cat.Id == id)
                    field = cat;
            }
            field.MarkOld();
            return field;
        }