查询得到oledbdatareader后，有三种方式支持数据读取，如下：
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//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：
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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服务器之家。
原文链接：https://www.cnblogs.com/dullfish/p/6214983.html
