using System;
using System.Data.SqlClient;
namespace DataReaderDemo
{
class Program
{
static void Main(string[] args)
{
string constr = "Server = .; user=name;pwd=mima;database=mysql";
SqlConnection myCon = new SqlConnection(constr);
try
{
myCon.Open();
string sql = "select * from mytable01 ";
SqlCommand mycom = new SqlCommand(sql, myCon);
//声明DataReader
SqlDataReader mydr;
mydr = mycom.ExecuteReader();
if (mydr.HasRows)
{
Console.WriteLine("mytable01中存在数据");
}
else
{
Console.WriteLine("mytable01中不存在任何数据");
}
//----------------方法----------------------
Console.WriteLine("第一列的数据类型"+mydr.GetDataTypeName(0));
Console.WriteLine("获取对应列的名称:(第一列)"+mydr.GetName(0));
string mystr = "age"; //直接写会报异常,需要有个转换的过程
Console.WriteLine(mydr.GetOrdinal(mystr));
/* 此时将上面的15行的str,换为
* string sql = "select * from mytable01 where id=1";
if (mydr.Read())
{
Console.WriteLine("取得指定字段的数据:" + mydr.GetValue(0));
}
*/
/*将15行的 str更改为:
* string sql = "select * from mytable01 where gender='男'";
object[] myobj = new object[mydr.FieldCount];
while(myde.Read()){
mydr.GetValues(myobj);
foreach (object item in myobj)
{
Console.Write(item + "\t");
Console.WriteLine();
}
}
*/
//访问DataReader 对象时使用索引要比字段名称快很多
while (mydr.Read())
{
Console.WriteLine(mydr[0].ToString()+",");
Console.WriteLine(mydr[1].ToString() + ",");
Console.WriteLine(mydr["gender"].ToString());
}
//----------------属性----------------------
Console.WriteLine("表中有几个字段:"+mydr.FieldCount);
Console.WriteLine("是否关闭:"+mydr.IsClosed);
mydr.Close();
Console.WriteLine("是否关闭:" + mydr.IsClosed);
}
catch(Exception ex)
{
Console.WriteLine(ex.Message.ToString());
}
finally
{
myCon.Close();
}
Console.Read();
}
}
}
作者:Czhenya
链接:https://czhenya.blog.csdn.net/article/details/77484468
来源:CSDN
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