Question

请问如何用SqlDataReader构造一个高效率的查询数据集

Answer 1

#region "私有变量"///<summary>/// 表示一个到数据库的打开的连接 ///</summary>private System.Data.SqlClient.SqlConnection Con =new SqlConnection(); ///<summary>/// 表示执行对象是SQl还是存储过程 ///</summary>private System.Data.SqlClient.SqlCommand Cmd =new SqlCommand(); ///<summary>/// 表示用于填充 System.Data.DataSet 和更新数据库的一组数据命令和到数据库的连接 ///</summary>private System.Data.SqlClient.SqlDataAdapter Dtapt =new SqlDataAdapter(); ///<summary>/// 表示要在数据库中生成的事务 ///</summary>private System.Data.SqlClient.SqlTransaction sqlTran; ///<summary>/// 提供从数据源读取数据行的只进流的方法 ///</summary>private SqlDataReader dtrValue =null; #endregion#region"数据库连接处理"///<summary>/// 获得webconfig中的 默认 Sql连接字符串 ///</summary>privatestring strConSql { get { return System.Configuration.ConfigurationManager.AppSettings["SQLConntionStr"].ToString(); } } #endregion#region "事务处理"///<summary>/// 开始事务 ///</summary>publicvoid BeginTransaction() { if (Con.State == ConnectionState.Closed) { //打开连接 OpenCn(); //开始事务if (sqlTran ==null) { sqlTran = Con.BeginTransaction(); } Cmd.Transaction = sqlTran; } } ///<summary>/// 提交事务 ///</summary>publicvoid CommitTransection() { sqlTran.Commit(); sqlTran.Dispose(); sqlTran =null; CloseCn(); } ///<summary>/// 回滚事务 ///</summary>publicvoid RollbackTransection() { sqlTran.Rollback(); sqlTran.Dispose(); sqlTran =null; CloseCn(); } #endregion#region"返回分页表数据Datatable [Read] 方式获取数据,数据量建议在查询结果在10000条记录内"///<summary>/// 用于分页控件，返回需要显示页的数据和记录条数 ///</summary>///<param name="p_strSql">SQL语句</param>///<param name="p_CmdParms">SQL参数和其对应值</param>///<param name="p_intStart">开始记录</param>///<param name="p_intPageSize">每页显示记录条数</param>///<param name="out_intCount">返回记录条数</param>///<returns>查询数据集</returns>protected DataTable ExecuteReadTable(string p_strSql, SqlParameter[] p_CmdParms, int p_intStart, int p_intPageSize, refint out_intCount) { return ExecuteReadTable(CommandType.Text, p_strSql, p_CmdParms, p_intStart, p_intPageSize, ref out_intCount); } ///<summary>/// 1. 根据存储过程和参数值得到DataTable 值 /// 2. 根据SQL的得到DataTable 值 ///</summary>///<param name="p_objCmdType">是存储过程还是SQL</param>///<param name="p_intStart">开始记录</param>///<param name="p_intPageSize">每页显示条数</param>///<param name="p_strSql">可是是SQL 也可以是存储过程</param>///<param name="p_CmdParms">SqlParameter参数列表</param>///<param name="out_intCount">返回总记录数</param>///<returns>返回DataTable</returns>protected DataTable ExecuteReadTable(CommandType p_objCmdType, string p_strSql, SqlParameter[] p_CmdParms, int p_intStart, int p_intPageSize, refint out_intCount) { DataTable dtb =new DataTable(); DateTime dtStart = DateTime.Now; dtrValue = ExecuteReader(p_objCmdType, p_strSql, p_CmdParms); if (dtrValue ==null) { CloseCn(); return dtb; } int intColLength = dtrValue.FieldCount; for (int i =0; i < intColLength; i++) { //构造sql的table dtb.Columns.Add(dtrValue.GetName(i), GetColType(i)); } DataRow dr; int k =0; if (dtrValue.HasRows) { //读取数据行值while (dtrValue.Read()) { //读取分页间数据if (p_intStart <= k && k < p_intStart + p_intPageSize) { dr = dtb.NewRow(); //读取每列值for (int j =0; j < intColLength; j++) { //读取每列的值 dr[dtrValue.GetName(j)] = GetValue(j, GetFieldType(j).ToString()); } dtb.Rows.Add(dr); } k++; } //删除了当前页所有数据则读上一页数据if (k <= p_intStart) { while (k <= p_intStart) { p_intStart = p_intStart - p_intPageSize; } k =0; dtrValue = ExecuteReader(p_objCmdType, p_strSql, p_CmdParms); if (dtrValue.HasRows) { while (dtrValue.Read()) { //读取分页间数据if (p_intStart <= k && k < p_intStart + p_intPageSize) { dr = dtb.NewRow(); //读取每列值for (int j =0; j < intColLength; j++) { //读取每列的值 dr[dtrValue.GetName(j)] = GetValue(j, GetFieldType(j).ToString()); } dtb.Rows.Add(dr); } k++; } } } } CloseCn(); SEHR.BLL.Function.AddSQLLog.WriteLog(p_strSql, dtStart.TimeOfDay.ToString(), DateTime.Now.TimeOfDay.ToString(), Convert.ToString(DateTime.Now - dtStart)); if (out_intCount ==0) { out_intCount = k;//获得总行数并且返回到页面 } return dtb; } #endregion#region "ExecuteReader 执行SQL语句"///<summary>/// ExecuteReader ///</summary>///<param name="p_objCmdType">命令类型 1CommandType.Text SQL语句 2CommandType.StoredProcedure存储过程</param>///<param name="p_strSQL">命令类型 1 SQL语句 2存储过程名称</param>///<param name="p_CmdParms">SqlParameter</param>///<returns>SqlDataReader</returns>private SqlDataReader ExecuteReader(CommandType p_objCmdType, string p_strSQL, SqlParameter[] p_CmdParms) { SqlDataReader dtrRet =null; try { //打开连接 OpenCn(); //命令行连接 Cmd.Connection = Con; Cmd.CommandText = p_strSQL; //是SQL语句还是存储过程 Cmd.CommandType = p_objCmdType; //循环CmdParms值if (p_CmdParms !=null) { foreach (SqlParameter objParm in p_CmdParms) { Cmd.Parameters.Add(objParm); } } dtrRet = Cmd.ExecuteReader(); Cmd.Parameters.Clear(); return dtrRet; } catch (Exception e) { string strErr =string.Empty; //p_CmdParms 参数值if (p_CmdParms !=null) { foreach (SqlParameter objParm in p_CmdParms) { strErr += objParm.ParameterName +" ='"+ objParm.Value +"' "; } } if (Con.State != ConnectionState.Closed && sqlTran ==null) { Cmd.Parameters.Clear(); CloseCn(); } // 写错误日志 SEHR.BLL.Function.AddMsgLog.AddError("SqlBase", e.Message +""n"r SQL : "+ p_strSQL +""n"r 参数 : "+ strErr, e.StackTrace); returnnull; } finally { //如果连接打开并且没有事务和SqlDataReader事件 则关闭连接if (Con.State != ConnectionState.Closed && sqlTran ==null&& dtrRet ==null) { Cmd.Parameters.Clear(); CloseCn(); } } } #endregion