C# OleDbDataReader快速读取数据

Z时代
2024-01-10
分类：技术分享

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：
耗时：{0}s", time1.TotalSeconds));
Console.WriteLine(string.Format("方法二：
耗时：{0}s", time2.TotalSeconds));
Console.WriteLine(string.Format("方法三：
耗时：{0}s", time3.TotalSeconds));
Console.ReadKey();
}