.net中使用oracle数据库分页的土办法

/// <summary>
 /// Oracle通用分页查询函数 by 菩提树下的杨过 2010-01-07
 /// </summary>
 /// <param name="tableName">表名</param>
 /// <param name="fields">(要查询的)字段列表</param>
 /// <param name="sqlWhere">查询条件(不带where)</param>
 /// <param name="orderFields">排序字段</param>
 /// <param name="pageSize">分页大小</param>
 /// <param name="pageIndex">页索引</param>
 /// <param name="recordCount">(输出参数)记录总数</param>
 /// <param name="pageCount">(输出参数)分页总数</param>
 /// <returns></returns>
  public DataSet QueryOracle(string tableName, string fields, string sqlWhere, string orderFields, int pageSize, int pageIndex, out int recordCount, out int pageCount)
         {
 if (string.IsNullOrEmpty(sqlWhere)) { sqlWhere = "1=1"; }
             DataSet ds = null;
             EnLib.Database _db = null;
             recordCount = 0;
             pageCount = 0;
 try
             {
                 _db = EnLib.DatabaseFactory.CreateDatabase();
 //先计算总记录数
  string sql = string.Format("select Count(*) from {0} where {1}", tableName, sqlWhere);
                 recordCount = int.Parse(_db.ExecuteScalar(CommandType.Text, sql).ToString());
 
 //再确定总页数
  if (recordCount % pageSize == 0)
                 {
                     pageCount = recordCount / pageSize;
                 }
 else
                 {
                     pageCount = recordCount / pageSize + 1;
                 }
 
 if (pageIndex <= 0) { pageIndex = 1; }
 
 if (pageIndex > pageCount) { pageIndex = pageCount; }
 
 //确定起始点
  int _start = pageSize * (pageIndex - 1) + 1;
 
 int _end = _start + pageSize - 1;
 
 if (_end > recordCount) { _end = recordCount; }
 
 
 //如果fields为*，则查询所有字段列表
  if (fields == "*")
                 {
                     sql = "select table_name,column_name from user_tab_columns where table_name='" + tableName.ToUpper().Trim() + "'";
                     IDataReader dr = _db.ExecuteReader(CommandType.Text, sql);
 string _allFields = "";
 while (dr.Read())
                     {
                         _allFields += dr[1] + ",";
                     }
                     dr.Close();
                     fields = _allFields.Trim(',');
 if (orderFields.Length == 0) 
                     {
                         orderFields = fields.Split(',')[0];
                     }
                 }
 
 if (orderFields.Length == 0)
                 {
                     orderFields = fields.Split(',')[0];
                 }
 
 //构造sql语句
                 sql = string.Format("select RecordID,{0} from (select rownum RecordID,{0} from (select {0} from {1} where {2} order by {3})) where RecordID between {4} and {5}", fields, tableName, sqlWhere, orderFields, _start, _end);
 
 
 
                 ds = _db.ExecuteDataSet(CommandType.Text, sql);
             }
 catch
             {
 
             }            
 
 return ds;
         }