C# OleDbDataReader快速数据读取方式(3种)

查询得到oledbdatareader后，有三种方式支持数据读取，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); 
}

关于速度的描述，下面我们来简单验证一下。

有一个数据库，数据库中的表test有105945行数据，设计一个循环读取来测试他们的读取速度。

测试源码如下：

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 = "探测号";
      string s3 = "x";
      string s4 = "y";
      string s5 = "h";
      string sql = string.format("select {0},{1},{2},{3},{4} from 管点表", s1, s2, s3, s4, s5);
      timespan time1 = new timespan();
      timespan time2 = new timespan();
      timespan time3 = new timespan();

      int count = 50;

      //数据库中查询的表有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耗时：{0}s", time1.totalseconds));
      console.writeline(string.format("方法二：\r\n耗时：{0}s", time2.totalseconds));
      console.writeline(string.format("方法三：\r\n耗时：{0}s", time3.totalseconds)); 
      console.readkey();
    }

循环50次结果，即50*105945：

100次循环结果:，即100*105945：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。