C# OleDbDataReader快速數據讀取方式(3種)

2020-01-24 00:01:13

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查詢得到OleDbDataReader后，有三種方式支持數據讀取，如下：

//方法一**速度中等OleDbDataReader reader = command.ExecuteReader();while (reader.Read()){  var t1 = reader[0]; }//方法二**速度最慢OleDbDataReader reader = command.ExecuteReader();while (reader.Read()){  var t1 = reader["字段名"]; }//方法三**速度最快OleDbDataReader reader = command.ExecuteReader();while (reader.Read()){  var t1 = reader.GetValue(0); }

關于速度的描述，下面我們來簡單驗證一下。

有一個數據庫，數據庫中的表TEST有105945行數據，設計一個循環讀取來測試他們的讀取速度。

測試源碼如下：

static void Main(string[] args)    {      string connstr = string.Format("Provider=Microsoft.Jet.OLEDB.4.0 ;Data Source={0};", "F://2.mdb");      string s1 = "ID";      string s2 = "探測號";      string s3 = "X";      string s4 = "Y";      string s5 = "H";      string sql = string.Format("SELECT {0},{1},{2},{3},{4} FROM 管點表", s1, s2, s3, s4, s5);      TimeSpan time1 = new TimeSpan();      TimeSpan time2 = new TimeSpan();      TimeSpan time3 = new TimeSpan();      int count = 50;      //數據庫中查詢的表有105945行      for (int i = 0; i < count; i++)      {        using (OleDbConnection conn = new OleDbConnection(connstr))        {          #region          conn.Open();          OleDbCommand command = conn.CreateCommand();          command.CommandText = sql;          OleDbDataReader reader = command.ExecuteReader();          DateTime now = DateTime.Now;          while (reader.Read())          {            var t1 = reader[0]; var t2 = reader[1]; var t3 = reader[2]; var t4 = reader[3]; var t5 = reader[4];          }          time1 = time1 + (DateTime.Now - now);          #endregion        }      }      for (int i = 0; i < count; i++)      {        using (OleDbConnection conn = new OleDbConnection(connstr))        {          #region          conn.Open();                    OleDbCommand command2 = conn.CreateCommand();          command2.CommandText = sql;          OleDbDataReader reader = command2.ExecuteReader();          DateTime now = DateTime.Now;          while (reader.Read())          {            var t1 = reader[s1]; var t2 = reader[s2]; var t3 = reader[s3]; var t4 = reader[s4]; var t5 = reader[s5];          }          time2 = time2 + (DateTime.Now - now);          #endregion        }      }      for (int i = 0; i < count; i++)      {        using (OleDbConnection conn = new OleDbConnection(connstr))        {          #region          conn.Open();          OleDbCommand command3 = conn.CreateCommand();          command3.CommandText = sql;          OleDbDataReader reader = command3.ExecuteReader();          DateTime now = DateTime.Now;          while (reader.Read())          {            var t1 = reader.GetValue(0); var t2 = reader.GetValue(1); var t3 = reader.GetValue(2); var t4 = reader.GetValue(3); var t5 = reader.GetValue(4);          }          time3 = time3 + (DateTime.Now - now);          #endregion        }      }      Console.WriteLine(string.Format("方法一：/r/n耗時：{0}s", time1.TotalSeconds));      Console.WriteLine(string.Format("方法二：/r/n耗時：{0}s", time2.TotalSeconds));      Console.WriteLine(string.Format("方法三：/r/n耗時：{0}s", time3.TotalSeconds));       Console.ReadKey();    }

循環50次結果，即50*105945：