public override MyCatSchemaCollection GetColumns(string[] restrictions)
        {
            string[] keys = new string[4];
            keys[0] = "TABLE_CATALOG";
            keys[1] = "TABLE_SCHEMA";
            keys[2] = "TABLE_NAME";
            keys[3] = "COLUMN_NAME";
            MyCatSchemaCollection dt = Query("COLUMNS", null, keys, restrictions);

            dt.RemoveColumn("CHARACTER_OCTET_LENGTH");
            dt.Name = "Columns";
            QuoteDefaultValues(dt);
            return(dt);
        }