快捷導(dǎo)航

C# OleDbDataReader快速數(shù)據(jù)讀取方式(3種)

更新時(shí)間：2019年12月12日 10:38:55 作者：DullFish

這篇文章主要介紹了C# OleDbDataReader快速數(shù)據(jù)讀取方式(3種)，文中通過示例代碼介紹的非常詳細(xì)，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

查詢得到OleDbDataReader后，有三種方式支持?jǐn)?shù)據(jù)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(guān)于速度的描述，下面我們來簡單驗(yàn)證一下。

有一個(gè)數(shù)據(jù)庫，數(shù)據(jù)庫中的表TEST有105945行數(shù)據(jù)，設(shè)計(jì)一個(gè)循環(huán)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(diǎn)表", s1, s2, s3, s4, s5);
      TimeSpan time1 = new TimeSpan();
      TimeSpan time2 = new TimeSpan();
      TimeSpan time3 = new TimeSpan();

      int count = 50;

      //數(shù)據(jù)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(shí)：{0}s", time1.TotalSeconds));
      Console.WriteLine(string.Format("方法二：\r\n耗時(shí)：{0}s", time2.TotalSeconds));
      Console.WriteLine(string.Format("方法三：\r\n耗時(shí)：{0}s", time3.TotalSeconds)); 
      Console.ReadKey();
    }

循環(huán)50次結(jié)果，即50*105945：