C产品在市场上有哪些独特优势？

本文共计609个文字，预计阅读时间需要3分钟。

在查询到 OleDbDataReader 后，支持以下三种数据读取方式：

1. 方法一：中等速度csharpOleDbDataReader reader=command.ExecuteReader();while (reader.Read()){ var t1=reader[0];}

2. 方法二：较慢速度csharpOleDbDataReader re=command.ExecuteReader();

3. 方法三：未知速度csharpOleDbDataReader reader=command.ExecuteReader();

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易盾网络。